Breve Historia de los Aerogeles de SíliceUn gran número de personas da por sentado que los aerogeles son productos recientes de la tecnología moderna. En realidad, los primeros aerogeles se prepararon en 1931. Por aquel entonces, Steven. S. Kistler del College of the Pacific de Stockton (California) consiguió demostrar que un «gel» contenía una red sólida y continua del mismo tamaño y forma que un gel húmedo.La forma más lógica de demostrar esta hipótesis consistía en extraer el líquido del gel húmedo sin dañar el componente sólido.Como suele ocurrir, esa forma lógica incluía muchos obstáculos. Si dejamos que un gel se seque por sí solo, éste encogería, a menudo hasta alcanzar una fracción de su tamaño original. Esta reducción de tamaño normalmente iba acompañada de un fuerte craquelado del gel. Kistler supuso, correctamente, que el componente sólido del gel era microporoso, y que el punto de contacto entre el líquido y el vapor del líquido en evaporación empleaba grandes fuerzas de tensión superficial que colapsaban la estructura del poro. Kistler entonces descubrió el aspecto fundamental de la producción del aerogel: [«Obviamente, para producir un aerogel [Kistler acuñó este término], hay que reemplazar de algún modo el líquido por aire sin permitir que la superficie del líquido se pierda por el interior del gel. Si mantenemos el líquido bajo una presión siempre superior a la presión del vapor y aumentamos la temperatura, dicho líquido se convertirá, al alcanzar la temperatura crítica, en un gas sin que se den dos fases de manera simultánea» (S.S. Kistler, J. Phys. Chem. 34, 52, 1932).]Los primeros geles que estudió Kistler eran geles de sílice preparados mediante la condensación ácida de silicato de sodio acuoso. Sin embargo, los intentos de preparar aerogeles mediante la conversión del agua de estos geles en un fluido supercrítico no tuvieron éxito. En vez de formarse un aerogel de sílice, el agua supercrítica redisolvió la sílice, que después precipitó mientras se evaporaba el agua. Entonces se sabía que el agua de los geles acuosos se podía sustituir con líquidos orgánicos miscibles. Kistler lo intentó de nuevo, lavando bien los geles de sílice con agua (para retirar las sales del gel) y sustituyendo el agua por alcohol. Al convertir el alcohol en un fluido supercrítico y permitir su evaporación, se formaron los primeros verdaderos aerogeles. Los aerogeles de Kistler eran muy similares a los aerogeles de sílice que se preparan en la actualidad. Eran materiales transparentes, de baja densidad y muy porosos que despertaban un gran interés académico.Durante los años siguientes, Kistler caracterizó completamente los aerogeles de sílice y preparó aerogeles con muchos otros materiales, incluyendo alúmina, óxido de tungsteno, óxido de hierro, óxido de estaño, tartrato de níquel, celulosa, nitrato de celulosa, gelatina, agar-agar, albúmina de huevo y caucho.Algunos años después Kistler abandonó el College of the Pacific y consiguió un puesto en la empresa Monsanto Corp.Monsanto comenzó a comercializar un producto conocido simplemente como «aerogel». El Aerogel de Monsanto era un material de sílice granular. Poco se sabe sobre las condiciones de procesamiento que se utilizaron para este material, pero se asume que su producción seguía los métodos de Kistler. El Aerogel de Monsanto fue utilizado como agente aditivo o tixotrópico en cosméticos y

dentífricos. Durante las tres décadas siguientes se avanzó poco en el campo de los aerogeles. Al cabo del tiempo, en los años sesenta, el desarrollo de la económica sílice «ahumada» debilitó el comercio del aerogel, por lo que Monsanto dejó de producirlo.Los aerogeles ya habían pasado a la historia cuando, a finales de los años setenta, el gobierno francés mantuvo contactos conStanislaus Teichner de la Université Claude Bernard (Lyon) buscando un método para almacenar oxígeno y carburante de misiles dentro de materiales porosos. Hay una leyenda transmitida entre los investigadores pertenecientes a la comunidad de los aerogeles sobre lo que sucedió después. Teichner le confirió a uno de sus pupilos licenciados el trabajo de preparar y estudiar los aerogeles con el objetivo mencionado anteriormente. Sin embargo, siguiendo el método de Kistler, que incluía dos laboriosos y prolongados pasos de intercambio de solvente, se necesitaron varias semanas para preparar el primer aerogel.Teichner le comunicó a su pupilo que necesitaría un gran número de muestras de aerogel para completar su trabajo. Al comprobar que para llevar a cabo tal tarea, necesitaría muchos, muchos años, el estudiante abandonó el laboratorio deTeichner sufriendo un ataque de nervios. Cuando regresó al laboratorio después de un descanso tenía una gran motivación por descubrir un mejor proceso sintético. El resultado fue uno de los mayores avances dentro de la ciencia del aerogel, concretamente en cuanto a la aplicación de la química sol-gel en la preparación del aerogel de sílice. Este proceso reemplazó el silicato de sodio que utilizaba Kistler por un alcoxilo (tetrametilortosilicato, TMOS). Al hidrolizar TMOS en una solución de metanol se producía un gel en sólo un paso (denominado «alcogel»). Con ello se eliminaron dos de los inconvenientes del método de Kistler, más concretamente, el paso del intercambio de agua por alcohol y la presencia de sales inorgánicas en el gel. Al secar los alcogeles bajo unas condiciones de alcohol supercrítico se produjeron aerogeles de sílice de calidad óptima.Durante los años siguientes, el grupo de trabajo de Teichner y otros investigadores utilizaron este método para preparar otros aerogeles de gran variedad con óxidos metalicos.Tras este descubrimiento los avances dentro del campo de los aerogeles se sucedieron de forma rápida a medida que aumentaba el número de investigadores en la materia. Algunos de los logros notables son:Durante la primera mitad de los años ochenta los investigadores de física de partículas se dieron cuenta de que los aerogeles de sílice serían un medio ideal para la producción y la detección de la radiación de Cherenkov. Para realizar estos experimentos se necesitaban grandes losas transparentes de aerogel de sílice. Utilizando el método del TMOS, se fabricaron dos detectores de gran tamaño. Uno utilizaba 1700 litros de aerogel de sílice en el detector TASSO de laDeutsches Elektronen Synchrotron (DESY) de Hamburgo y otro en CERN utilizaba 1000 litros de aerogel de sílice preparado en la Universidad de Lund de Suecia.La primera planta piloto para la producción de bloques de aerogel de sílice que utilizaba el método del TMOS fue establecida por miembros del grupo Lund de Sjobo (Suecia). Dicha planta incluía una autoclave diseñada para soportar las altas presiones y temperaturas que se dan con el metanol supercrítico (240ºC y 80 atmósferas). No obstante, en 1984 la autoclave desarrolló un escape durante una

secuencia de producción. La habitación donde se encontraba el recipiente se llenó rápidamente de vapores de metanol y posteriormente explotó. Afortunadamente no hubo que lamentar víctimas mortales, aunque las instalaciones quedaron totalmente destrozadas. La planta se volvió a construir y aún hoy en día produce aerogeles de sílice utilizando el proceso del TMOS. La planta es controlada en la actualidad por Airglass Corp.En 1983 Arlon Hunt y el Microstructured Materials Group del Laboratorio de Berkeley (California) descubrieron que el compuesto TMOS, muy tóxico, podría sustituirse con tetraetilortosilicato (TEOS), que es un reactivo mucho más seguro.La calidad de producción de los aerogeles no disminuyó.Al mismo tiempo el Microstructured Materials Group del Laboratorio de Berkeley descubrió que el alcohol del interior del gel podría reemplazarse por dióxido de carbono líquido antes de llevarse a cabo el secado supercrítico sin dañar el aerogel. Este hecho significaba un avance importante en cuanto a la seguridad, ya que el punto crítico del CO2 (31ºC y 1050psi) tiene lugar bajo unas condiciones mucho menos agudas que el punto crítico del metanol (240ºC y 1600psi).Además, a diferencia del alcohol, el dióxido de carbono no representa ningún peligro de explosión. Este proceso se utilizó por primera vez para producir placas de aerogel de sílice transparente a partir de TEOS.La empresa alemana BASF desarrolló simultáneamente métodos de sustitución de CO2 para la preparación de perlas de aerogel a partir de silicato de sodio. Este material se ha estado produciendo hasta 1996 con el nombre comercial de«BASOGEL».En 1985 el Catedrático Jochen Fricke organizó el primer Simposio Internacional sobre Aerogeles (ISA) en Würzburg (Alemania). En esta conferencia científicos de todo el mundo presentaron hasta un total de 25 ponencias. Se celebraron posteriores ISAs en los años 1988 en Montpellier (Francia), 1991 en Würzburg, y 1994 en Berkeley (California). La cuarta ISA estableció un récord de asistencia con 151 participantes, 10 ponencias invitadas, 51 ponencias de contribución y 35 exposiciones de cartel. La quinta ISA se celebró recientemente en Montpellier y contó con casi 200 asistentes.A finales de los años ochenta científicos del Laboratorio Internacional de Lawrence Livermore (LLNL) dirigidos por Larry Hrubesh prepararon el aerogel de sílice de menor densidad del mundo (y el material sólido de menor densidad). Dicho aerogel tenía una densidad de 0,003g/cm3, sólo tres veces mayor que la del aire.Poco después, Rick Pekala, miembro también del LLNL, siguiendo las técnicas utilizadas para preparar aherrójeles inorgánicos, preparó aerogeles de polímeros orgánicos. Entre éstos estaban los aerogeles de resorcinol-formaldehido y de melamina-formaldehido. Los aerogeles de resorcinol-formaldehido se podían pirolizar para producir aerogeles de carbón puro. Este hecho abrió nuevas expectativas dentro de la investigación del aerogel.Thermalux, L.P. fue fundada en 1989 por Arlon Hunt, y por otros colaboradores, en Richmond (California). Thermalux operaba una autoclave de 300 litros para la producción de bloques de aerogel de sílice a partir de TEOS utilizando el proceso de sustitución del dióxido de carbono. Thermalux preparó una gran cantidad de aerogeles, pero, desafortunadamente, dejó de funcionar en 1992.

El aerogel de sílice, preparado en el Jet Propulsion Laboratory (Laboratorio de Propulsión a Chorro), ha ido a bordo del Space Shuttle en varias misiones. En estos vuelos se utiliza el aerogel de muy baja densidad para recoger y traer a la tierra muestras de polvo cósmico de alta velocidad.Investigadores de la University of New Mexico, dirigidos por C. Jeff Brinker y por Doug Smith, y de otras instituciones cada vez están más cerca de eliminar el paso de secado supercrítico utilizado en la producción de aerogel mediante la modificación química de la superficie del gel previa al secado. Esta investigación tuvo como consecuencia la fundación de Nanopore para comercializar aerogeles de bajo coste.En 1992, Hoechst Corp. también inició en Francfort un programa de aerogeles granulares de bajo coste.En 1994, la Aerojet Corp. inició en Sacramento (California) un proyecto cooperativo con el Laboratorio de Berkeley, el LLNL y otros para comercializar los aerogeles utilizando el proceso de sustitución del dióxido de carbono. Aerojet consiguió la autoclave de 300 litros antiguamente controlada por Thermalux, produciendo así varias formas de aerogeles de sílice de resorcinol-formaldehido y de carbono. Sin embargo, abandonaron el programa en 1996.Cada vez es mayor el número de investigaciones y desarrollos, por lo que, en un futuro muy cercano, seguramente habrá muchas más aplicaciones y avances en la tecnología de los aerogeles.

Cómo se Preparan los Aerogeles de Sílice(Translation from English by "mailto:chicken17@arrakis.es" , University of Granada, Spain)La discusión posterior se basa en los siguientes términos:Hidrólisis: Reacción de un alcoxilo metálico (M-OR) con el agua, formándose un hidróxido metálico (M-OH).Condensación:Una reacción de condensación tiene lugar cuando dos hidróxidos metálicos (M-OH + HO-M) se combinan para producir una especie de óxido metálico (M-O-M). Esta reacción forma una molécula de agua.Sol:Solución de varios reactivos que sufren reacciones de hidrólisis y de condensación. El peso molecular del tipo de óxido que se produce no deja de aumentar. A medida que crecen, estas especies suelen empezar a unirse unas a otras formando una red tridimensional.Punto de gel:Momento en que la red de partículas de óxido unidas abarca el contenedor donde se encuentra el sol. Cuando se alcanza el punto de gel, el sol se convierte en Alcogel.Alcogel (gel húmedo):Cuando se alcanza el punto de gel, la mezcla forma una sustancia rígida denominada alcogel. El alcogel puede extraerse del contenedor original donde se encuentra, y mantenerse fuera de éste. Un alcogel consta de dos partes, una sólida y otra líquida. La parte sólida es la red tridimensional de partículas de óxido

unidas. La parte líquida (el solvente original del sol) rellena el espacio libre que queda alrededor de la parte sólida. Aparentemente ambas partes de un alcogel ocupan el mismo volumen.Fluido supercrítico:Sustancia que se encuentra por encima de su presión y temperatura críticas. Un fluido supercrítico cuenta con algunas propiedades en común con los líquidos (densidad y conductividad térmica) y otras con los gases (abarca el volumen del contenedor donde se encuentra y no tiene tensión superficial).Aerogel:Sobrante de un alcogel cuando se le extrae la parte líquida sin dañar la parte sólida (esto se consigue normalmente mediante la extracción supercrítica). Si se hace correctamente, el aerogel conserva la forma original del alcogel y como mínimo un 50% (normalmente>85%) del volumen del alcogel.Xerogel:Remanente cuando se extrae la parte líquida de un alcogel mediante evaporación o mediante métodos similares. Los xerogeles pueden conservar su forma original, aunque a menudo se agrietan. Normalmente, en el caso de los xerogeles, la reducción de tamaño que se produce durante el secado es extrema (-90%).

Química sol-gelPor lo general, la formación de aerogeles comprende dos pasos principales: la formación de un gel húmedo y el secado del gel húmedo para formar un aerogel. En un principio, los geles húmedos se preparaban mediante la condensación acuosa del silicato de sodio o de un material similar. A pesar del buen funcionamiento de este proceso, la reacción formaba sales dentro del gel que sólo se podían extraer lavándo el gel una y otra vez (procedimiento largo y laborioso). Gracias al rápido desarrollo de la química sol-gel durante las últimas décadas, la gran mayoría de los aerogeles de sílice que se preparan en la actualidad utiliza precursores de alcoxilo de silicona. Los más utilizados son el tetrametil ortosilicato (TMOS, Si(OCH3)4) y el ortosilicato tetraetilo (TEOS, Si(OCH2CH3)4). Sin embargo, se pueden utilizar muchos otros alcoxilos que contengan varios grupos funcionales orgánicos para que el gel adquiera propiedades diferentes. La química sol-gel basada en alcoxilos evita la formación de los poco deseados productos derivados de la sal, además de posibilitar un control mucho mayor sobre el producto final. La ecuación química equilibrada para la formación de un gel de sílice a partir de TEOS es:

Si(OCH2CH3)4 (líquido) = SiO2 (sólido) + 4HOCH2CH3 (líquido)

Esta reacción normalmente se lleva a cabo en etanol; la densidad final del aerogel depende de la concentración de los monómeros de alcoxilo de silicona que hay en la solución. Cabe destacar que la estoiquiometría de la reacción precisa dos moles de agua por cada mol de TEOS. En la práctica, esta cantidad de agua tiene como consecuencia una reacción incompleta y unos aerogeles débiles y empañados. La mayoría de las fórmulas para preparar aerogeles utiliza por tanto un mayor porcentaje de agua del que aconseja la ecuación equilibrada (entre 4 y 30 equivalentes).

CatalizadoresLa cinética de la reacción anterior es poco práctica por su lentitud a temperatura ambiente, por lo que a menudo se necesitan varios días para llevarla a cabo totalmente. Para acortar el proceso se añaden catalizadores ácidos o básicos a la fórmula. Las propiedades microestructurales, físicas y ópticas del producto de aerogel final dependerán de la cantidad y el tipo de catalizador que se emplee.Los catalizadores ácidos pueden consistir en un ácido prótido cualquiera, como el HCl. Los catalizadores básicos por lo general utilizan amoníaco o amoníaco amortiguado con fluoruro amónico. Los aerogeles preparados con catalizadores ácidos normalmente encogen más durante el secado supercrítico y pueden ser menos transparentes que los aerogeles preparados con un catalizador básico. La descripción precisa de los efectos microestructurales de varios catalizadores es bastante compleja, ya que la subestructura de las partículas primarias de los aerogeles puede ser difícil de distinguir con un microscopio electrónico.Todos contienen unas partículas pequeñas (2-5nm de diámetro), normalmente esféricas o con forma de huevo. Por el contrario, en el caso de los catalizadores ácidos, estas partículas pueden resultar «menos sólidas» (con la apariencia de una bola de cuerda) que las obtenidas en los geles preparados con catalizadores básicos.A medida que progresan las reacciones de condensación, el sol se convertirá en un gel rígido. Es en este punto cuando normalmente se extrae el gel del molde, aunque hay que mantener cubierto el gel con alcohol para evitar que evapore el líquido contenido dentro de los poros del gel. La evaporación puede dañar seriamente el gel y disminuir la calidad del aerogel resultante.

Aerogeles de un paso frente a aerogeles de dos pasosLos geles normales preparados a partir de TEOS con catalizadores ácidos o con catalizadores básicos suelen encuadrarse dentro de los geles «de un paso» (para la reacción sólo se necesita «un recipiente»). Un método desarrollado recientemente emplea TEOS pre-polimerizado como fuente de sílice. El TEOS pre-polimerizado se prepara calentando una solución de etanol de TEOS con una cantidad sub-estoiquiométrica de agua y un catalizador ácido. El solvente se extrae mediante destilación, quedando un fluido viscoso que contiene óxido-alcoxilo de silicona de un peso molecular superior. Este material se redisuelve en etanol y reacciona con el agua restante bajo condiciones básicas hasta que se produce la gelatinación. Los geles que se preparan siguiendo este método se denominan geles catalizados ácidos/ básicos «de dos pasos». El TEOS pre-polimerizado se encuentra disponible en los EEUU y es comercializado por Silbond Corp. (Silbond H-5).Estas condiciones de procesamiento ligeramente distintas provocan unos pequeños pero importantes cambios en el producto final de aerogel. Normalmente, los aerogeles preparados mediante un catalizador básico de un paso son mecánicamente más fuertes, aunque también más quebradizos, que los aerogeles de dos pasos. Sin embargo, los aerogeles de dos pasos tienen una distribución del tamaño de los poros más pequeña y estrecha, además de ser normalmente más transparentes óptimamente que los aerogeles de un solo paso.

Maduración y remojo

Las reacciones de hidrólisis y de condensación del reactivo alcoxilo de silicona a menudo se consideran completas cuando el sol alcanza el punto de gel, aunque no suele ser este el caso. El punto de gel no es más que el momento en que las especies de sílice que se encuentran bajo el proceso de polimerización abarcan el volumen del contenedor donde está el sol. En ese momento la columna de sílice del gel contiene una importante cantidad de grupos alcoxilos sin reaccionar. De hecho, aún puede darse hidrólisis y condensación hasta que se complete la gelatinación. Uno de los errores más comunes en la preparación de aerogeles de sílice se comete al no tener en cuenta ese aspecto. La solución es fácil, hay que tener paciencia. La red de sílice será más fuerte si se le da el tiempo suficiente. Este proceso puede tener un mejor resultado controlando el pH y el contenido de agua de la solución que cubre el aerogel. Uno de los procedimientos que se suelen utilizar para la maduración de los geles catalizados básicos consiste en remojar el gel en una mezcla de alcohol y agua proporcional al sol original bajo un pH de 8-9 (amoníaco). Es recomendable dejar reposar los geles en esta solución hasta un máximo de 48 horas.Este paso, así como los posteriores pasos de procesamiento, es controlado mediante difusión. O sea que la introducción o extracción de material dentro o fuera del gel no se ve afectada por convección o mezcla (debido a la solidez de la red de sílice).Sin embargo, la difusión sí se ve afectada por el grosor del gel. En breve, el tiempo necesario para cada paso de procesamiento aumenta de forma radical a medida que aumenta el grosor del gel. Este hecho limita la producción práctica de los aerogeles a piezas de 1 a 2 centímetros de grosor.Una vez haya madurado el gel y antes de proceder al secado, se debe extraer todo el agua que queda dentro de los poros. Para ello, se debe remojar el gel varias veces en alcohol puro hasta que no quede nada de agua. Una vez más, el tiempo que se necesita para este proceso depende del grosor del gel. Si se deja agua dentro del gel, ésta no podrá ser extraída mediante el secado supercrítico, por lo que el resultado será un aerogel opaco, blanco y muy denso.

Secado supercríticoEl último proceso y el más importante a la hora de preparar aerogeles de sílice es el secado supercrítico. Durante este proceso se extrae el líquido remanente dentro del gel, dejando sólo la red de sílice entrelazada. El proceso se puede llevar a cabo mediante la evaporación de etanol por encima de su punto crítico (altas temperaturas, o sea muy peligroso) o mediante un intercambio del solvente con CO2 seguido de una evaporación supercrítica (bajas temperaturas, o sea menos peligroso). Este proceso se debe llevar a cabo en una autoclave especialmente diseñada para este fin (en el caso del secado de CO2 se pueden utilizar las autoclaves de poco tamaño que emplean los usuarios de microscopios electrónicos para preparar muestras biológicas). El proceso consiste en los pasos siguientes: los alcogeles se colocan en la autoclave (previamente rellenada con etanol). Después se presuriza el sistema a una presión de al menos 750-850psi con CO2 y se enfría hasta alcanzar los 5-10ºC.Se introduce CO2 líquido dentro del recipiente hasta que se haya extraído todo el etanol de dicho recipiente y del interior de los geles. Cuando ya no quede etanol

en los geles, se calienta el recipiente hasta una temperatura superior a la temperatura crítica del CO2 (31ºC). A medida que se calienta el recipiente, aumenta la presión del sistema. Se suelta el CO2 con cuidado para mantener una presión ligeramente superior a la presión crítica del CO2 (1050psi). El sistema debe mantenerse bajo estas condiciones durante un corto periodo de tiempo. A continuación se suelta de forma lenta y controlada el CO2 a temperatura ambiente. Como en los pasos anteriores, el tiempo que se necesita para llevar a cabo este proceso depende del grosor de los geles. El proceso puede durar entre 12 horas y 6 días. Tras este proceso se puede abrir el recipiente y admirar así la belleza intrínseca de los aerogeles.La gráfica siguiente muestra las condiciones del proceso de sustitución/ secado con dióxido de carbono y las del proceso de secado con alcohol.

Fórmulas generalesAerogel de sílice catalizado básico de un pasoPara preparar un aerogel con una densidad aproximada de 0,08g/cm3, el tiempo de gel debería estar entre los 60 y los 120 minutos, dependiendo de la temperatura.1. Mezclar dos soluciones:1. Solución de sílice con 50mL de TEOS y 40mL de etanol.2. Solución catalizadora con 35mL de etanol, 70mL de agua, 0,275mL de amoníaco 30% acuoso y 1,21mL de fluoruro amónico de 0,5M.2. Añadir lentamente la solución catalizadora a la solución de sílice mientras se remueve.3. Verter la mezcla dentro de un molde apropiado y esperar a que se produzca la gelatinación.4. Proceder siguiendo los pasos descritos en los apartados anteriores.

Aerogel de sílice catalizado básico de dos pasosPara preparar un aerogel con una densidad aproximada de 0,08g/cm3, el tiempo de gel debería estar entre los 30 y los 90 minutos, dependiendo de la temperatura.1. Mezclar dos soluciones:1. Solución de sílice con 50mL de sílice precondensada (Silbond H-5, o un equivalente) y 50mL de etanol.2. Solución catalizadora con 35mL de etanol, 75mL de agua y 0,35mL de amoníaco 30% acuoso.2. Añadir lentamente la solución catalizadora a la solución de sílice mientras se remueve.3. Verter la mezcla dentro de un molde apropiado y esperar a que se produzca la gelatinación.4. Proceder siguiendo los pasos descritos en los apartados anteriores."http://www.lbl.gov/http://www.lbl.gov"

Cómo Manejar los Aerogeles de Sílice sin RomperlosLo primero que hace la mayoría de la gente cuando toca aerogeles de sílice por primera vez es romperlos en un millón de trozos. En la radio y televisión de vez en cuando se oyen cosas como: «Un nuevo material de la Era Espacial que aguanta hasta 1000 veces su propio peso…». Esto quizás sea verdad, pero no hay que

olvidar que, para un material de tan baja densidad, «1000 veces su propio peso» no es en absoluto mucho peso. Además, también es importante destacar que el aerogel de sílice no es más que otro tipo de cristal. Si el aerogel no se maneja con cuidado, se romperá, aunque, si se tiene cuidado, este material se puede manejar y se le puede dar forma de manera muy eficaz. Algunas sugerencias son:No se deben levantar piezas grandes de aerogel por las esquinas. Pasar una plancha fina de metal o de otro material consistente por debajo del aerogel para desplazarlo.El aerogel de sílice dura mucho más si se encuentra bajo compresión. Para ponerlo bajo compresión, se puede simplemente sellar al vacío el aerogel dentro de una bolsa de plástico (un envasador de alimentos al vacío funciona bien). Este método es muy útil cuando se quieren enviar muestras por correo.La mejor herramienta para cortar un aerogel de sílice es una sierra con filo de diamante, similar a la que se utiliza para cortar gemas y piedras. Lo más difícil es mantener inmóvil el material. Una herramienta de succión es muy útil.La mayor parte del aerogel de sílice se destruye al entrar en contacto con líquidos, aunque se puede proteger con agua Los cambios momentáneos de presión ambiental pueden provocar que el aerogel se rompa debido a la posible salida o entrada de gases en la estructura porosa. Hay que tener cuidado si se pone el aerogel a altas presiones.Un gran número de personas se pregunta si existen peligros tóxicos asociados con el manejo del aerogel de sílice. Manejar un aerogel con las manos al descubierto podría dañar la piel. Esto se debe a la absorción de humedad y aceites de la piel que ejercen los poros del aerogel. Es más una molestia que un problema tóxico, y puede evitarse con un par de guantes. Al cortar y darle forma a un aerogel se suele producir una nube de polvo fino. Las partículas del aerogel que hay en el polvo son homogéneas y redondas, por lo que no suponen un daño de laceración (a diferencia de los asbestos, por ejemplo). No obstante, sería recomendable trabajar con ropa aislante o con un buen respirador para no inhalar el polvo de aerogel.

Silica Aerogels for Absorbing Kinetic EnergyWhen someone who has never seen a piece of silica aerogel holds some for the first time, the following chain of events usually results. The observer first notices the transparency and light weight of the aerogel and makes some sort of remark about these properties. Then the piece is held between two fingers and gently squeezed. The aerogel gives a little, and springs back. Then a little more force is applied and...pffttt, the piece shatters into a thousand pieces, most of which find a home deep in the carpeting, never to be seen again. Not surprisingly, researchers who have spent the time and effort required to make silica aerogels are usually very reluctant to hand them out to just anyone. Because of this, an application of silica aerogels that has been largely overlooked is their use as an absorber of kinetic energy (impacts) in safety and protective devices.

Energy Absorbing MaterialsIn very simplified terms, materials absorb kinetic energy by plastic deformation, elastic deformation, brittle fracture, or by the fluid dynamics of gases or liquids within the material. Materials used today for absorbing impacts are commonly

organic foams, such as expanded polystyrene, polyurethanes, polyethers, or polyethylene. These typically show elastomeric or plastic behavior. Silica aerogels, being an inorganic solid, are inherently brittle. A brittle material would, at first, seem to be a poor choice for a cushioning material. However, as silica aerogels are usually very low density materials, the collapse of the solid network occurs gradually, spreading the force of impact out over a longer time. Additionally, as silica aerogels are an open-pored material, the gas contained within the bulk of the solid in forced outwards as the material collapses. In doing so, the gas must pass through the "http://eande.lbl.gov/ECS/aerogels/sapore.htm" of the aerogel. The frictional forces caused as a gas passes through a restricted opening are indirectly proportional to the square of the pore diameter. As silica aerogels have very narrow pores (~20-50 nm), gases rapidly passing through the material will absorb a considerable amount of energy. Therefore, the energy of an object impacting a silica aerogel is taken up by the aerogel by the collapse of its solid structure and the release of gas from within the material.An effective material for use in safety devices will serve to minimize the force felt by the object (or person) to be protected. This is usually done by spreading the deceleration of the impacting object over a longer period of time. The graphic below shows load versus time for a silica aerogels sample, and two other materials. The samples were cubes 5 cm on a side and were crushed by an 8 lb. weight traveling at 11 ft/sec. The red curve represents a silica aerogel with a density of 0.1g/cm3, the yellow curve is expanded polystyrene, and the green is an elastomeric polypropylene foam. The plots show that both the aerogel and the polystyrene foam reduce the maximum load produced to a very low level. It may, therefore, seem that readily available polystyrene foam may be a more appropriate material than the more unusual silica aerogel.The situation is not as straightforward as this. Many organic foams produce a significant amount of rebound when they are impacted. This transfers a portion of the energy absorbed by the material back into the object that impacted it (such as a human head). This rebound effect can often do further damage to the object being protected. The plot of deflection (distance moved by the impacting object) vs. time for silica aerogel and polystyrene shown below demonstrates the differences of these materials(Note: Deflection data are derived from measured load values and are for comparison purposes only). The polystyrene (yellow), which behaves elastically and plastically, is crushed by the impacting weight (positive deflection) but then springs back to a considerable fraction of its original volume. Conversely, the weight that impacts the silica aerogel (red) travels a certain distance into the material and then comes to a complete stop without bouncing. This is an important phenomenon to consider when developing materials for safety and protective devices.These data were collected using a Dynatup Drop-Weight System with the kind assistance of "http://www.grci.com/grcinst" ,Santa Barbara, CA, a division of "http://www.grci.com/" .Environmental ConcernsThe production and use of silica aerogels is environmentally benign. No significantly hazardous wastes are produced during their production. The disposal

of silica aerogels is perfectly natural. In the environment, they quickly crush into a fine powder that is essentially identical to one of the most common substances on Earth, namely, sand. Additionally, silica aerogels are completely non-toxic and non-flammable. If they eventually find their way into widespread use as protective materials, they could eliminate a very large amount of unwanted plastic materials.Potential UsesThe attractive energy absorbing properties of silica aerogels may lead to their use in various applications. These may include personal protection in motor vehicles, protection of sensitive equipment such as aircraft flight data recorders, and protection of electronic equipment such as laptop computer hard drives.The Surface Chemistry of Silica AerogelsSilica aerogels contain primary particles of 2-5 nm in diameter. Silica particles of such a small size have an extraordinarily large surface-to-volume ratio (~2 x 109 m-1) and a corresponding high specific surface area (~900 m2/g). It is not surprising, therefore, that the chemistry of the interior surface of an aerogel plays a dominant role in its chemical and physical behavior. It is this property that makes aerogels attractive materials for use as catalysts, catalyst substrates, and adsorbents.The nature of the surface groups of a silica aerogel are strongly dependent on the conditions used in its preparation. For example, if an aerogel is prepared using the supercritical alcohol drying process, its surface may consist primarily of alkoxy-(-OR) groups. On the other hand, with the carbon dioxide drying process the surface is almost exclusively covered with hydroxyl (-OH) groups. The extent of hydroxyl- coverage is ~5 -OH/nm2, a value consistent with other forms of silica. This value, combined with their high specific surface area, means that silica aerogels present an extremely large number of accessible hydroxyl groups. Silica aerogels are therefore a somewhat acidic material. A more striking effect of the hydroxyl surface is seen the physical behavior of silica aerogels. As with most hydroxyl surfaces, the surface of silica aerogels can show strong hydrogen-bonding effects. Because of this, silica aerogels with hydroxyl surface are extremely hygroscopic. Dry silica aerogels will absorb water directly from moist air, with mass increases of up to 20%. This absorption has no visible effect on the aerogel, and is completely reversible. Simply heating the material to 100-120 degrees C will completely dry the material in about an hour (or longer, depending on thickness). As the sample cools, water will reabsorb quickly (mass increases can be seen almost immediately).While the adsorption of water vapor does not harm silica aerogels, contact with liquid water has disastrous results. The strong attractiveforces that the hydroxyl surface exerts on water vapor also attracts liquid water. However, when liquid water enters a nanometer-scale pore, the surface tension of water exerts capillary forces strong enough to fracture the solid silica backbone.The net effect is a complete collapse of the aerogel monolith. The material changes from a transparent solid with a definite shape to a fine white powder. The powder has the same mass and total surface area as the original aerogel, but has lost its solid integrity. Silica aerogels with fully hydroxylated surfaces are, therefore, classified as "hydrophilic".

This would appear to pose a significant problem to using silica aerogels in exposed environments. Fortunately, this problem can be easily circumvented by converting the surface hydroxyl (-OH) groups to a non-polar (-OR) group. This is effective when R is one of many possible aliphatic groups, although trimethylsilyl- groups are the most common. The derivitization can be performed before (on the wet gel) or after (on the aerogel) supercritical drying. This completely protects the aerogel from damage by liquid water by eliminating the attractive forces between water and the silica surface. In fact, silica aerogels treated in this way can notbe wet by water, and will float on its surface indefinitely. Silica aerogels that have been derivitized in this way are classified as "hydrophobic".The illustrations below demonstrate the interaction of water with the pore structure and solid backbone of silica aerogels.

The Pore Structure of Silica AerogelThe pore structure of silica aerogels is difficult to describe in words. Unfortunately, the available methods of characterizing porosity do only a slightly better job. The International Union of Pure and Applied Chemistry has recommended a classification for porous materials where pores of less than 2 nm in diameter are termed "micropores", those with diameters between 2 and 50 nm are termed "mesopores", and those greater than 50 nm in diameter are termed "macropores". Silica aerogels possess pores of all three sizes. However, the majority of the pores fall in the mesopore regime, with relatively few micropores. The pore size distribution of a single-step silica aerogel is shown below:It is very important when interpreting porosity data to indicate the method used to determine the data. Various measurement techniques can give differing results for the same sample. The entire range of characterization methods has been applied to silica aerogels, including:

Gas/Vapor adsorption This is the most widely available and utilized method for determining aerogel porosity. In this technique a gas, usually nitrogen, at its boiling point, is adsorbed on the solid sample. The amount of gas adsorbed depends of the size of the pores within the sample and on the partial pressure of the gas relative to its saturation pressure. By measuring the volume of gas adsorbed at a particular partial pressure, the Brunauer, Emmit and Teller (BET) equation gives the specific surface area of the material. At high partial pressures the hysteresis in the adsorption/desorption curves (called "isotherms"), the Kelvin equation gives the pore size distribution of the sample. The pore size distribution shown above was determined using a 40-point nitrogen adsorption/desorption analysis. Gas adsorption methods are generally applicable to pore in the mesopore range. However, microporosity information can be inferred through mathematical analyses such as t-plots or the Dubinin-Radushevich method.Gas adsorption can not effectively determine macropores. For a detailed description of this procedure, see the IUPAC guidelines for "Reporting Physisorption Data for Gas/Solid Systems" in Pure and Applied Chemistry, volume 57, page 603, (1985).

Mercury Porosimetry: This technique is generally not effective for aerogels. The high compressive forces encountered in forcing mercury into the pores of an aerogel cause its structure to collapse.

Scattering Methods (x-ray, neutron and visible light): Scattering methods involve the angle dependent deflection of radiationby features within the sample. These features can be solid particles or pores. Scattering efficiency is greatest when the wavelength of the radiation used is comparable to the features being studied. X-ray and neutron scattering are particularly well suited for determining the fractal geometry of the aerogel pore network. See the section on "file:///C|/Mis documentos/saoptic.htm" for a discussion of visible light scattering.

Other methods: Gas/solid NMR, electron microscopy of replicants, and atomic force microscopy have also been used to characterize the pore network of silica aerogels with limited success.Because of the limitations of these methods, a major problem in aerogel science remains unresolved. If the mass, density, and total pore volume of an aerogel are measured, it is apparent that there is a substantial amount of porosity that is not accounted for. This obviously results from the drawbacks of using gas adsorption to determine the pore volume. It is assumed that the "missing porosity" lies in the micro- or macropore regimes, areas not measured effectively by this method.One final important aspect of the aerogel pore network is its "open" nature and interconnectedness. Pores in various materials are either open or closed depending on whether the pore walls are solid or themselves porous (or at least "holey"). A macroscopic example of a open-pored material is a common sponge, while "bubble wrap" packaging is an example of a closed-pore material. In a closed-pore material, gases or liquids can not enter the pore without breaking the pore walls. This is not the case with an open-pore structure. In this instance, gases or liquids can flow from pore to pore, with limited restriction, and eventually through the entire material. It is this property that makes silica aerogels effective materials for gas phase catalysts, microfiltration membranes, adsorbents, and substrates for chemical vapor infiltration.

Physical Properties of Silica AerogelsNote: Most of the properties listed here are significantly affected by the conditions used to prepare the aerogel and any subsequent post-processing.Physical properties of silica aerogelsProperty Value CommentsApparent Density 0.003-0.35 g/cm3Most common density is ~0.1g/cm3Internal Surface Area 600-1000 m2/g As determined by nitrogen adsorption/desorption% Solids 0.13-15% Typically 5% (95% free space)Mean Pore Diameter ~20 nm As determined by nitrogen adsorption/desorption (varies with density)Primary Particle Diameter 2-5 nm Determined by electron microscopyIndex of Refraction 1.0-1.05 Very low for a solid material

Thermal Tolerance to 500 C Shrinkage begins slowly at 500 C, increases with inc. temperature. Melting point is >1200 CCoefficient of Thermal Expansion 2.0-4.0 x 10-6 Determined using ultrasonic methods Poisson's Ratio 0.2 Independent of density. Similar to dense silica.Young's Modulus 106-107 N/m2 Very small (<104x) compared to dense silicaTensile Strength 16 kPa For density = 0.1 g/cm3.Fracture Toughness ~0.8 kPa*m1/2 For density = 0.1 g/cm3. Determined by 3-point bendingDielectric Constant ~1.1 For density = 0.1 g/cm3. Very low for a solid materialSound Velocity Through the Medium100 m/sec For density = 0.07 g/cm3. One of the lowest velocities for a solid material

Optical Properties of Silica AerogelsThe optical properties of silica aerogels are best described by the phrase "silica aerogels are transparent". This may seem obvious, as silica aerogels are made of the same material as glass. However, the situation is not as simple as that comparison.While distant objects can be viewed through several centimeters of silica aerogel, the material displays a slight bluish haze when an illuminated piece is viewed against a dark background and slightly reddens transmitted light. These effects are a result of Rayleigh scattering effects. The various aspects of optical transmission through silica aerogel are discussed below.

Rayleigh ScatteringThe vast majority of the light that we see when we look at objects is scattered light (light that reaches our eyes in an indirect way). The phenomenon of scattering leads to several well known natural effects, such as blue skies, red sunsets, the white (or gray) color of clouds, and poor visibility on foggy days. Scattering results from the interaction of light with inhomogeneities in solid, liquid, or gaseous materials. The actual entity that causes scattering, called the scattering center, can be as small as a single large molecule (with an inherent inhomogeneity) or clusters of small molecules arranged in a non-uniform way. However, scattering becomes more effective when the size of the scattering center is similar to the wavelength of the incident light. This occurs in small particles (~400-700 nm in diameter for visible light) that are separated from on another, or by larger, macroscopic, particles with inherent irregularities. When scattering centers are smaller in size than the wavelength of the incident light, scattering is much less effective. In silica aerogels, the primary particles have a diameter of ~2-5 nm, and do not contribute significantly to the observed scattering. However, scattering does not necessarily arise from solid structures. There is in silica aerogels, a network of pores which can act, themselves, as scattering centers. The majority of these are much smaller (~20 nm) than the wavelength of visible light. There are, however, invariably a certain number of larger pores that scatter visible light. Control of the number an size of these larger pores is, to a certain degree, possible by modifying the sol-gel chemistry used to prepare the aerogel. As scattering efficiency is dependent on the size of the scattering center, different wavelengths will scatter with varying

magnitudes. This causes the reddening of transmitted light (red light has a longer wavelength, and is scattered less by the fine structure of aerogels) and the blue appearance of the reflected light off silica aerogels.A simple method can be used to quantitatively measure the relative contributions of Rayleigh scattering and the wavelength-independent transmission factor (due to surface damage and imperfections) for silica aerogels prepared with different recipes and/or drying procedures. Briefly, the transmission spectrum of an aerogel slab of known thickness is measured and the transmission is plotted against the inverse fourth power of the wavelength. These data are fit to the equation: where T = transmittance, A = wavelength independent transmission factor, C = intensity of Rayleigh scattering, t = sample thickness, and Lambda = wavelength. From this plot A and C can be determined. Aerogels with a high value of A and a low value of C will be the most transparent. Scattering may also be accompanied by absorbance which will further attenuate the transmitted light.

Visible Transmission SpectrumThe intrinsic absorbance of silica is low in the visible region. Therefore the tranmittance in this region is primarily attenuated by scattering effects. As wavelengths become progressively shorter, scattering increased, eventually cutting off transmission near 300 nm. Weak absorbances begin to appear in the near infrared, and again cuts off transmission around 2700-3200 nm.There is then a "visible window" of transmission through silica aerogel that is an attractive feature of this material for daylighting applications.

Infrared SpectrumAs the spectrum moves into the infrared, scattering becomes less important, and standard molecular vibrations account for the spectral structure. A strong, broad absorbance band is usually observed at 3500 cm-1, due to O-H stretching vibrations. A weaker O-H bending vibration band is seen at 1600 cm-1. Both adsorbed water and surface -OH groups contribute to these bands. Thoroughly drying the sample before analysis will eliminate vibrations due to water, while surface -OH groups can be significantly eliminated by firing the aerogel at 500 degrees C. The Si-O-Si fundamental vibration gives the strong band at ~1100 cm-1. There is a region of high infrared transparency between 3300 and 2000 cm-1. This allows a certain amount of thermal radiation to pass through silica aerogel and lower its thermal insulative performance. Addition of additives that absorb radiation in this region can remedy this problem.

Thermal Properties of Silica AerogelsAfter preparing the first silica aerogels, Kistler proceeded to characterize them as thoroughly as possible. One of the extraordinary properties that he discovered was their very low thermal conductivity. Kistler also found that the thermal conductivity decreased even further under vacuum. However, in the 1930's thermal insulation was a low priority and applications of aerogels in insulation systems was not pursued. The renaissance of aerogel technology around 1980 coincided with an increased concern for energy efficiency and the environmental effects of chlorofluorocarbons (CFC's). It was then readily apparent that silica aerogels were an attractive alternative to traditional insulation due to their high insulating value and environment-friendly production methods. Unfortunately, the production costs

of the material were prohibitive to cost-sensitive industries such as housing. A significant research effort was undertaken, and is continuing, at several institutions worldwide (including Berkeley Lab) to circumvent this problem by increasing the insulative performance and lowering the production costs of silica aerogels.The passage of thermal energy through an insulating material occurs through three mechanisms; solid conductivity, gaseous conductivity, and radiative (infrared) transmission. The sum of these three components gives the total thermal conductivity of the material. Solid conductivity is an intrinsic property of a specific material. For dense silica, solid conductivity is relatively high (a single-pane window transmits a large amount of thermal energy). However, silica aerogels possess a very small (~1-10%) fraction of solid silica. Additionally, the solids that are present consist of very small particles linked in a three-dimensional network (with many "dead-ends"). Therefore, thermal transport through the solid portion of silica aerogel occurs through a very tortuous path and is not particularly effective.The space not occupied by solids in an aerogel is normally filled with air (or another gas) unless the material is sealed under vacuum. These gases can also transport thermal energy through the aerogel. The pores of silica aerogel are open and allow the passage of gas (albeit with difficulty) through the material. The final mode of thermal transport through silica aerogels involves infrared radiation. A advantage of silica aerogels for insulation applications is their visible transparency (which will allow their use in windows and skylights). However, they are also reasonably transparent in the infrared (especially between 3-5 microns). At low temperatures, the radiative component of thermal transport is low, and not a significant problem. At higher temperatures, radiative transport becomes the dominant mode of thermal conduction, and must be dealt with. The infrared spectrum of silica.Attempting to calculate the total thermal conductivity arising from the sum of these three modes can be difficult, as they modes are coupled (changing the infrared absorbency of the aerogel also changes the solid conductivity, etc.). It is generally easier to measure the total thermal conductivity directly rather than predict the effect of changing one component. To achieve this, the Microstructured Materials Group at Berkeley Lab designed and built an economical, but accurate instrument for measuring the thermal conductivity of large aerogel panels. The Vacuum Insulation Conductivity Tester (On Rollers) -VICTOR, is a thin-film heater based device that can measure the thermal conductivity of panels up to 26 cm on edge, with pressures of various gases down to 0.01 Torr.

Minimizing the solid component of thermal conductivityThere is little that can be done to reduce thermal transport through the solid structure of silica aerogels. Lower density aerogels can be prepared (as low as 0.003 g/cm3), which reduces the amount of solid present, but this leads to aerogels that are mechanically weaker. Additionally, as the amount of solids decreases the mean pore diameter increases (with an increase in the gaseous component of the conductivity). These are, therefore, generally not suitable for insulation applications. However, as noted above, the tortuous solid structure of silica aerogels leads to a intrinsically low thermal transport. Granular aerogels have an

extremely low solid conductivity component. This is due to the small point of contact between granules in an aerogel bed.However, in granular aerogel, the inter-granule voids increase the overall porosity of the material thereby requiring a higher vacuum to achieve the maximum performance (see below).

Minimizing the gaseous component of thermal conductivity.A typical silica aerogel has a total thermal conductivity of ~0.017 W/mK (~R10/inch). A major portion of this energy transport results from the gases contained within the aerogel. This is the transport mode that is most easily controllable. As a consequence of their fine pore structure, the mean pore diameter of an aerogel is similar in magnitude to the mean free path of nitrogen (and oxygen) molecules at standard temperatures and pressures. If the mean free path of a particular gas were longer than the pore diameter of an aerogel, the gas molecules would collide more frequently with the pore walls than with each other. If this were the case, the thermal energy of the gas would be transferred to the solid portion of the aerogel (with its low intrinsic conductivity).Lengthening the mean free path relative to the mean pore diameter can be accomplished in three ways; by filling the aerogel with a gas with a lower molecular mass (and a longer mean free path) than air, by reducing the pore diameter of the aerogel, and by lowering the gas pressure within the aerogel.The first of these methods is generally not practical, as light gases are relatively expensive and would eventually escape the system. The mean pore diameter can be reduced by increasing the density of the aerogel. However, any benefit from a lower gaseous conductivity component is counteracted by an increase in the solid conductivity component. The pore diameter can be reduced somewhat (while keeping the aerogel's density constant) by using the two-step process to prepare the aerogel. The greatest improvement is found by reducing the gas pressure. Vacuum insulations are commonplace in various products (such as Thermos bottles). These systems generally require a high vacuum to be maintained indefinitely to achieve the desired performance. In the case of aerogels, however, it is only necessary to reduce the pressure enough to lengthen the mean free path of the gas relative to the mean pore diameter. This occurs for most aerogels at a pressure of about 50 Torr. This is a very modest vacuum that can be easily obtained and maintained (by sealing the aerogel in a light plastic bag).The graphic below shows Thermal Conductivity vs. Pressure curves obtained on VICTOR for single-step and two-step silica aerogels. The minimum value of ~0.008 W/mK corresponds to ~R20/inch.Minimizing the radiative component of thermal conductivityAs noted above, radiative component of thermal conductivity becomes more important as temperatures increase. If silica aerogels are to be used at temperatures above 200 degree C, this mode of energy transport must be suppressed. This can be accomplished by adding an additional component to the aerogel, either before or after supercritical drying. The second component must either absorb or scatter infrared radiation. A major challenge for this process is to add a component that does not interfere with the mechanical integrity of the

aerogel or increase its solid conductivity. One of the most promising additives is elemental carbon. Carbon is an effective absorber of infrared radiation and, in some cases, actually increases the mechanical strength of the aerogel.The graphic below shows Thermal Conductivity vs. Pressure curves obtained on VICTOR for pure single-step silica aerogel and single-step silica aerogel with 9% (wt/wt) carbon black. At ambient pressure the addition of carbon lowers the thermal conductivity from 0.017 to 0.0135 W/mK. The minimum value for the carbon composite of ~0.0042 W/mK corresponds to ~R30/inch.

Silica Aerogel Nanocomposite MaterialsIt was readily apparent to early researchers working on aerogels that they were ideal for use in composite materials. However, with much fundamental research needed into the preparation and properties of aerogels, this area has only recently been explored. In this discussion "composite" is used in the broadest sense of the term, where the final product consists of a "substrate" (the silica aerogel) and one or more additional phases (of any composition or scale). As all the materials considered here have a silica aerogel substrate, there is always at least one phase with physical structures with dimensions on the order of nanometers (the particles and pores of the aerogel). The additional phases may also have nanoscale dimensions, or may be larger (up to centimeters). Because of this the materials can legitimately be classified as "nanocomposites". There are generally three routes to aerogel nanocomposites: addition of the second component during the sol-gel processing of the material (before supercritical drying), addition of the second component through the vapor phase (after supercritical drying), and chemical modification of the aerogel backbone through reactive gas treatment.

Aerogel nanocomposites through Sol-Gel processingThis approach is the logical first route to aerogel nanocomposites and can produce many varieties of composites. There are, however, limitations to these procedures. Simply stated, a non-silica material is added to the silica sol before gelation. This added material may be a soluble organic or inorganic compound, insoluble powders, polymers, biomaterials, bulk fibers, woven cloths, or porous preforms. In all cases, the additional components must withstand the subsequent process steps used to form the aerogel (alcohol soaking, and supercritical drying). The conditions encountered in the CO2 drying process are milder than the alcohol drying process and are more amenable to forming composites. If the added components are bulk, insoluble materials (such as carbon fibers or mineral powders), steps must be taken to prevent the settling of the insoluble phase before gelation.This can often be accomplished by gently agitating the mixture until gelation is imminent. The silica aerogel with the best results from the addition of a small amount of carbon black to the sol using this technique.The addition of soluble inorganic or organic compounds to the sol provides a virtually unlimited number of possible composites.There are two criteria that must be met to prepare a composite by this route. First, the added component must not interfere with the gelation chemistry of the silica precursor. This is difficult to predict in advance, but rarely a problem if the added component is reasonably inert. The second problem encountered in this process is the leaching out of the added phases during the alcohol soak or supercritical drying

steps. This can be a significant impediment if a high loading of the second phase is desired in the final composite. When the addend component is a metal complex, it is often useful to use a binding agent, such as (CH3O)3SiCH2CH2NHCH2CH2NH2. This can bind with the silica backbone through the hydrolysis of its methoxysilane groups and chelate the metal complex with its dangling diamine. This general approach has been used by several research groups to prepare nanocomposites of silica aerogels or xerogels. After the gel has been dried, the resulting composite consists of a silica aerogel with metal ions atomically dispersed throughout the material. Thermal post-processing induces thermal diffusion and reduction of the metal ions, forming nanometer-scale metal particles within the aerogel matrix. These composites are being extensively studies for use a catalysts for gas-phase reactions. There is a photograph of composites prepared in this way in Aerogel nanocomposites through Chemical Vapor InfiltrationThe open of silica aerogels allows for easy transport of vapors throughout the entire volume of the material. This provides another route to an aerogel nanocomposite. Virtually any compound with at least a slight vapor pressure can be deposited throughout a silica aerogel. In fact, silica aerogels should be stored in a clean environment to prevent the unwanted absorption of volatile pollutants. To prevent subsequent desorption of the added phase, it is useful to convert the adsorbed material into a non-volatile phase by thermal or chemical decomposition. This can be done during, or after the initial deposition. The Microstructured Materials Group has prepared a wide variety of aerogel nanocomposites using this process, including:

Silica aerogel-Carbon composites These have been prepared through the decomposition of various hydrocarbon gases at high temperatures. However, due to the fine structure of silica aerogels, the decomposition take place at a much lower temperature (200-450 degrees C) than the corresponding decomposition in the absence of the aerogel. Carbon loadings ranging from 1-800% have been observed. Surprisingly, at lower loadings, the carbon deposition is relatively uniform throughout the volume of monolithic aerogel slabs. At higher loadings, the carbon begins to localize at the exterior surface of the composite monolith. Interesting aspects of these composites include electrical conductivity at higher loadings, and mechanical strengthening of the composite relative to the original aerogel.

Silica aerogel-Silicon compositesThe thermal decomposition of various organosilanes on a silica aerogel forms deposits of elemental silicon. In this case the rapid decomposition of the silane precursor leads to deposits localized near the exterior surface of the aerogel substrate. Thermal annealing of the composite induces crystallization of the silicon. The resulting composite, with 20-30 nm diameter silicon particles, exhibits strong visible photoluminescence at 600 nm.

Silica aerogel-Transition Metal composites Organo-transition metal complexes are idea precursors for this type of composite.

Even the least volatile of these possess a sufficient vapor pressure to be deposited within an aerogel. Under controlled conditions, these deposit uniformly throughout the entire volume of the aerogel monolith. Typically, the metal compounds are then thermally degraded to their base metals. These intermediate composites are generally highly reactive, due to the disperse nature of the metallic phase, and can be easily converted to metal oxides, sulfides, or halides. This process can be repeated several times to increase the loading of the metallic phase. Typically composites prepared in this way possess crystals of the desired metal compound on the order of 5-100 nm in diameter.The graphic below displays the magnetization/demagnetization curve for a silica aerogel/Fe3O4 composite prepared by this process. The curve shows that the composite is a "soft" ferromagnetic material. The magnetite crystals in this composite are 20-60 nm in diameter. Many appear to be single domain, as observed by electron microscopy.The Microstructured MaterialsGroup has a patent pending on various aspects of this process.

Aerogel nanocomposites through Energized Gas TreatmentThe Microstructured Materials Group has recently discovered a simple process that can alter the chemical structure of the silica(or other oxide) backbone of an aerogel. This process utilizes an energized reducing (or other) gas to form thin films of new material on the interior surface of the aerogel. The techniques used in this case are similar to standard plasma methods.However, the nanoscale pore structure of silica aerogels prohibit the formation of a plasma within an aerogel.Nevertheless, the centers of thick monoliths are affected by this process. In the simplest case, silica aerogel monoliths are partially reduced by energized hydrogen. The resulting composite consists of a silica aerogel with a thin layer of oxygen-deficient silica (SiOx) on the interior surface. As with other reduced silica materials, this material exhibits strong visible photoluminescence at 490-500 nm when excited by ultraviolet (330 nm) light. However, the process used in this case is relatively gentle, and does not alter the physical shape or optical transparency of the original aerogel. This composite is the basis for the aerogel.There is a photograph of this composite.The Microstructured Materials Group has a patent pending on this process ".As noted above, several aerogel nanocomposites exhibit strong visible photoluminescence. The spectra shown below are for the silicon nanoparticles/silica aerogel (red emitter) and gas-treated reduced silica aerogel composite (blue-green emitter)

Optical Oxygen Sensor Based on Silica AerogelSilica aerogels are ideal materials for active and passive components in optical sensors. Their visible transparency, high surface area, facile transport of gases through the material, thermal and chemical stability, and ability to be filled with additional active phases are the key properties that aerogels bring to sensor applications. The Microstructured Materials Group has recently discovered a new process that induces a permanent, visible photoluminescence in silica aerogels (see the section on aerogel composite materials). Shortly after these materials were prepared, it was observed that the intensity of the photoluminescence was

indirectly proportional to the amount of gaseous oxygen within the aerogel. The quenching of photoluminescence by oxygen is a phenomenon that is frequently observed in many luminescent materials.In simple terms, photoluminescence occurs when a material absorbs a photon of sufficient energy. The entity that absorbs the photon may be a discrete molecule, or a defect center in a solid-state material, and if often referred to a "carrier". When the photon has been absorbed, the carrier is moved into a high energy, "excited" state. The carrier will then relax back to its ground state after certain length of time. This "lifetime" of the excited state is usually on the order of nanoseconds to microseconds. The mechanism by which the carrier relaxes determines whether the photoluminescence is termed "fluorescence" or "photoluminescence". If an oxygen molecule collides with a carrier while it is in its excited state, the oxygen molecule will absorb the excess energy of the carrier and quench the photoluminescence. The oxygen molecule absorbs the energy and undergoes a triplet-to-singlet transition, while the carrier undergoes a non-radiative relaxation. The efficiency of the photoluminescence quenching is , therefore, determined by the number of collisions between the material containing the carrier, and oxygen molecules. As the collision frequency of gases is determined by the number of molecules present, the pressure (P), and temperature (T), at a given P and T, the quenching efficiency, and, consequently, the photoluminescence intensity will be determined by the concentration of oxygen in the atmosphere surrounding the material.Oxygen sensors based on this principle have been extensively studied. The most common sensor elements studied are those based on an organic or inorganic compound suspended in a thin silicone membrane. Advantages of using an aerogel-based sensor element over these systems include a more rapid response time (due to rapid diffusion of gases through the aerogel pore network), and improved resistance to photo-bleaching (as the photoluminescence is caused by stable defect centers in SiO2).The Microstructured Materials Group has built a prototype oxygen sensor based on this technology. The sensor is intended to perform as low cost, moderate sensitivity device operating most effectively in the concentration range of 0-30% oxygen. The sensor operates independently of the nature of the other gases present in the feed gas and of the feed gas flow rate. The prototype sensor has been sensor has been successfully operated over a temperature range of -25 to +85 degrees C (this range is based on other experimental limitations of the system, the actual usable range is larger). The highest sensitivity is observed at lower temperatures.The prototype sensor uses a Hg-arc lamp for excitation (330 nm), and a Si photodiode for detection of the emission (500nm). The prototype design can be easily miniaturized, and a device can be designed with built-in pressure and temperature compensation.This sensor is available for technology-transfer. The graphic below plots the measured photoluminescence intensity (irradiance) vs oxygen pressure (concentration gives a similar plot) at two temperatures using the prototype sensor.Silica Aerogels: Technology-Transfer Opportunities/Commercial AvailabilityTechnology Transfer

As an institution funded by the U. S. Government, Berkeley Lab actively seeks technology-transfer arrangements that will be mutually beneficial to Berkeley Lab and commercial entities. The following technologies developed by the Microstructured Materials Group are available for direct transfer:Methods of producing aerogel-based via chemical vapor infiltration methods.Methods of producing and other aerogels with altered chemical compositions.based on photoluminescent silica aerogel.For details on how to begin a partnership with Berkeley Lab, visit thehttp://www.lbl.gov/Tech-Transfer

Commercial AvailabilityIn 1994, the Microstructured Materials Group entered into a Cooperative Research And Development Agreement with http://www.aerojet.com/ .of Sacramento, California, USA and several other partners. This agreement was supported by anARPA-TRP grant and focused on development of a pilot-scale aerogel production plant. At the completion of the project in 1995, Aerojet idled this facility and has no current plans to continue in this area.Other potential U.S. sources of aerogels are http://www.nanopore.com , in Albuquerque, N.M. which focuses on lower-cost granular aerogels and http://www.aspensystems.com/ , in Marlboro, MA which produces flexible aerogel-based insulation for cryogenic systems.A new venture, Ocellus, in the San Fransisco area, is currently selling small quantities of R-F, carbon and silica aerogels. They are available through http://www.mkt-intl.com/aerogels/index.html In Europe, http://www.airglass.se/ in Lund, Sweden has made batch quantities of aerogels for many years, focusing on serving the needs of the high energy physics community."http://www.cabot-corp.com/cabot will soon introduce commercial-scale quantities of granular, ambient-pressure dried aerogel products.The http://www.taasi.com/ company in Ohio is developing various oxide materials for uses such as air purification and catalysis.Note: The Microstructured Materials Group has a limited, and ever decreasing, stock of silica aerogel monoliths of various sizes.In the past we have provided demonstration samples to interested parties. Regrettably, we can no longer continue this practice.We may provide samples to organizations interested in collaborative research with Berkeley Lab, or to assist in development of applications of aerogels with realistic commercial potential. We are sorry that we will not be able to help artists, designers, high schools, etc. unless there are extraordinary circumstances. To contact Microstructured Materials Group members go to the

A Partial Bibliography for Silica AerogelsNote: There are well over one thousand scholarly papers dealing with aerogels. The partial list below gives representative examples and an indication of the breadth of this field.THE INTERNATIONAL SYMPOSIA ON AEROGELS (ISA)1st ISA: Wurzburg, Germany September 23-25 1985 Proceedings: "Aerogels" Ed. J. Fricke Springer Proceedings in Physics 6, Springer-Verlag (Berlin) 19862nd ISA: Montpellier, France September 21-23, 1988

Proceedings: Colloque de Physique (Supplement au Journal de Physique, FASC. 4), C4-19893rd ISA: Wurzburg, Germany September 30 - October 2, 1991Proceedings: http://www.elsevier.com/locate/jnoncrysol vol. 145, 19924th ISA: Berkeley, California, USA. September 19-21, 1994Proceedings: http://www.elsevier.com/locate/jnoncrysol vol. 185-6, 19955th ISA: Montpellier, France September 8-10, 1997Proceedings:http://www.elsevier.com/locate/jnoncrysol vol. 225, 19986th ISA: Albuquerque, N.M., USA October 8-11, 2000Proceedings:http://www.elsevier.com/locate/jnoncrysol vol. 285, 2001PAPERS BY MICROSTRUCTURED MATERIALS GROUP MEMBERSAyers, M.R. and Hunt. A.J.2001 Observation of the Aggregation Behavior of Silica Sols Using Laser Speckle Contrast Measurements.Journal of Non-Crystalline Solids, 290:122-128Ayers, M.R. and Hunt. A.J.2001 Synthesis and Properties of Chitosan-Silica Hybrid Aerogels. Journal of Non-Crystalline Solids, 285:123-127Hunt. A.J., and Ayers, M.R.2001 Investigations of Silica Alcogel Using Coherent Light. Journal of Non-Crystalline Solids, 285:162-166.Hunt. A.J.1998 Light Scattering for Aerogel Characterization Journal of Non-Crystalline Solids, 225:303-306Ayers, M.R. and Hunt. A.J.1998 Molecular Oxygen Sensor Based on Photoluminescent Silica Aerogel. Journal of Non-Crystalline Solids,225:343-347Ayers, M.R. and Hunt. A.J.1998 Light Scattering Studies of UV-Catalyzed Gel and Aerogel Structure, Journal of Non-crystalline Solids , 225:325-329Ayers, M. R. and Hunt A.J.1998 Titanium Oxide Aerogels Prepared from Titanium Metal and Hydrogen Peroxide. Materials Letters, 34:290-293Ayers, M. R. and Hunt A.J.1998 Visibly Photoluminescent Silica Aerogels. Journal of Non-Crystalline Solids, 217:229-235Ayers, M. R. Song, X. Y., and Hunt A. J.1996 Preparation of Nanocomposite Materials Containing WS2, d-WN, Fe3O4, or Fe9S10 in a Silica Aerogel Host. Journal of Materials Science 31:6251-6257.Zeng, S. Q., A. Hunt, and R. Greif1995 Theoretical Modeling of Carbon Content to Minimize Heat Transfer In Silica Aerogel. Journal of Non-Crystalline Solids, 186: 271-277.Song, X. Y., W. Q. Cao, M. R. Ayers, and A. J. Hunt1995 Carbon Nanostructures In Silica Aerogel Composites. Journal of Materials Research 10: 251-254.Zeng, S. Q., A. Hunt, and R. Greif

1995 Transport Properties of Gas In Silica Aerogel. Journal of Non-Crystalline Solids 186: 264-270.Hunt, A. J., M. R. Ayers, and W. Q. Cao1995 Aerogel Composites Using Chemical Vapor Infiltration. Journal of Non-Crystalline Solids 185: 227-232.Lee, D., P. C. Stevens, S. Q. Zeng, and A. J. Hunt1995 Thermal Characterization of Carbon-Opacified Silica Aerogels. Journal of Non-Crystalline Solids 186: 285-290.Cao, W. Q., and A. J. Hunt1994 Photoluminescence of Chemically Vapor Deposited Si On Silica Aerogels. Applied Physics Letters 64: 2376-2378.Song, X. Y., W. Cao, and A. J. Hunt1994 AEM and HREM evaluation of carbon nanostructures in silica aerogels, Spring meeting of the Materials Research Society; pp. (6 p). San Francisco, CA (United States): Lawrence Berkeley Lab., California (United States)Cao, W. Q., and A. J. Hunt1994 Improving the Visible Transparency of Silica Aerogels. Journal of Non-Crystalline Solids 176: 18-25.Cao, W. Q., and A. J. Hunt1994 Thermal Annealing of Photoluminescent Si Deposited On Silica Aerogels. Solid State Communications 91: 645-648.Zeng, S. Q., A. J. Hunt, W. Cao, and R. Greif1994 Pore size distribution and apparent gas thermal conductivity of silica aerogel. Journal of Heat Transfer 116: 756-759.Hunt, A. J., C. A. Jantzen, W. Cao, R. S. Graves, and D. C. Wysocki1991 Aerogel. Gatlinburg, TN (United States): Philadelphia, PA (United States) ASTM (Symposium on insulation materials: testing and applications,Hunt, A., K. Lofftus, W. H. Bloss, and F. Pfisterer1988 Silica aerogel, a transparent high performance insulator. Hamburg, F.R. Germany: Pergamon Press,Oxford, GB (International Solar Energy Society biennial congress on advances in solar energy technology,Tewari, P. H., A. J. Hunt, K. D. Lofftus, J. G. Lieber, C. J. Brinker, D. E. Clark, and D. R. Ulrich1986 Microstructural studies of transparent silica gels and aerogels. Palo Alto, CA, USA: Materials Research Society,Pittsburgh, PA (Materials Research Society spring meetingTewari, P. H., K. D. Lofftus, and A. J. Hunt1985 Structure and chemistry of sol-gel derived transparent silica aerogel, 2. international conference on ultrastructure processing of ceramics, glasses and composites; pp. 17. Daytona Beach, Florida, USA: Lawrence Berkeley Lab., California (USA)Hunt, A. J., R. E. Russo, P. H. Tewari, and K. D. Lofftus1985 Aerogel: a transparent insulator for solar applications, INTERSOL '85 - Solar energy--the diverse solution; pp. 8. Montreal, Canada: Lawrence Berkeley Lab., California (USA)Hunt, A., P. Berdahl, K. Lofftus, R. Russo, and P. Tewari

1985 Advances in transparent insulating aerogels for windows, Solar buildings: realities for today - trends for tomorrow; pp. 138-141. Washington, DC, USA: Lawrence Berkeley Lab., California, MCC Associates, Inc., Silver Spring, MD (USA)Hunt, A., R. Russo, P. Tewari, K. Lofftus, E. Bilgen, and K. G. T. Hollands1985 Aerogel: A transparent insulator for solar applications. Montreal, Canada: Pergamon Books Inc.,Elmsford,NY (INTERSOL '85 - Solar energy--the diverse solution,Selkowitz, S. E., A. Hunt, C. M. Lampert, and M. D. Rubin1984 Advanced optical and thermal technologies for aperture control, Passive and hybrid solar energy update;pp. 10-19. Washington, DC, USA: Lawrence Berkeley Lab., Californialifornia, U.S. Department of Energy Assistant Secretary for Conservation and Renewable Energy, Washington, DC. Passive and Hybrid SolarEnergy DivisionHunt, A. J., and P. Berdahl1984 Structure data form light scattering studies of aerogel. Mater. Res. Soc. Symp. Proc. : 275-280.Hunt, A., P. Berdahl, K. Lofftus, R. Russo, and P. Terwari1984 Advances in transparent insulating aerogels for windows,Passive and hybrid solar energy update; pp.47-50. Washington, DC, USA: Lawrence Berkeley Lab., Californialifornia, U.S. Department of Energy Assistant Secretary for Conservation and Renewable Energy, Washington, DC. Passive and Hybrid Solar EnergyDivisionHunt, A. J.1983 Light-scattering studies of silica aerogels, International conference on ultrastructure processing of ceramics, glasses and composites; pp. 15. Gainesville, FL, USA: Lawrence Berkeley Lab., California (USA)

THERMAL PROPERTIESRettelbach, R., J. Sauberlich, S. Korder, and J. Fricke1995 Thermal Conductivity of Ir-Opacified Silica Aerogel Powders Between 10 K and 275 K. Journal of PhysicsD-Applied Physics 28: 581-587.Rettelbach, T., J. Sauberlich, S. Korder, and J. Fricke1995 Thermal Conductivity of Silica Aerogel Powders At Temperatures From 10 to 275 K. Journal ofNon-Crystalline Solids 186: 278-284.Hrubesh, L. W., and J. F. Poco1995 Thin Aerogel Films For Optical, Thermal, Acoustic and Electronic Applications. Journal of Non-Crystalline Solids 188: 46-53.Hrubesh, L. W., and R. W. Pekala1994 Thermal properties of organic and inorganic aerogels. Journal of Materials Research 9: 731-738.Zeng, S. Q., A. J. Hunt, W. Cao, and R. Greif1994 Pore size distribution and apparent gas thermal conductivity of silica aerogel. Journal of Heat Transfer 116: 756-759.Reiss, H.

1992 Heat transfer in thermal insulations. Physikalische Blaetter 48: 617-622.Bernasconi, A., T. Sleator, D. Posselt, J. K. Kjems, and H. R. Ott1992 Low-Temperature Specific Heat and Thermal Conductivity of Silica Aerogels. Journal of Non-Crystalline Solids 145: 202-206.Scheuerpflug, P., M. Hauck, and J. Fricke1992 Thermal Properties of Silica Aerogels Between 1.4-K and 330-K. Journal of Non-Crystalline Solids 145: 196-201.Bernasconi, A., T. Sleator, D. Posselt, J. K. Kjems, and H. R. Ott1992 Dynamic Properties of Silica Aerogels As Deduced From Specific-Heat and Thermal-ConductivityMeasurements. Physical Review B-Condensed Matter 45: 10363-10376.Posselt, D., J. K. Kjems, A. Bernasconi, T. Sleator, and H. R. Ott1991 The Thermal Conductivity of Silica Aerogel In the Phonon, the Fracton and the Particle-Mode Regime. Europhysics Letters 16: 59-65.Scheuerpflug, P., H. J. Morper, G. Neubert, and J. Fricke1991 Low-Temperature Thermal Transport In Silica Aerogels. Journal of Physics D-Applied Physics 24: 1395-1403.Xianping, Lu, Wang Peng, D. Buettner, U. Heinemann, O. Nilsson, J. Kuhn, and J. Fricke1991 Thermal transport in opacified monolithic silica aerogels. High Temperatures High Pressures 23: 431-436.Sleator, T., A. Bernasconi, D. Posselt, J. K. Kjems, and H. R. Ott1991 Low-Temperature Specific Heat and Thermal Conductivity of Silica Aerogels. Physical Review Letters 66: 1070-1073.Caps, R., G. Doll, J. Fricke, U. Heinemann, and J. Hetfleisch1989 Thermal Transport In Monolithic Silica Aerogel. Journal De Physique 50: C4113-C4118.Fricke, J.1989 Thermal insulation without CFC. Physik in Unserer Zeit 20: 189-191.Fricke, J., E. Hummer, H. J. Morper, and P. Scheuerpflug1989 Thermal Properties of Silica Aerogels. Journal De Physique 50: C487-C497.Buettner, D., R. Caps, U. Heinemann, E. Huemmer, A. Kadur, and J. Fricke1988 Thermal loss coefficients of low-density silica aerogel tiles. Sol. Energy 40: 13-15.Fricke, J., R. Caps, D. Buettner, U. Heinemann, E. Huemmer, and A. Kadur1987 Thermal loss coefficients of monolithic and granular aerogel systems. Sol. Energy Mater. 16: 267-274.OPTICAL PHENOMENAHrubesh, L. W., and J. F. Poco1995 Thin Aerogel Films For Optical, Thermal, Acoustic and Electronic Applications. Journal of Non-Crystalline Solids 188: 46-53.Zhu, L., Y. F. Li, J. Wang, and J. Shen1995 Structural and Optical Characteristics of Fullerenes Incorporated Inside Porous Silica Aerogel. Chemical Physics Letters 239: 393-398.Emmerling, A., R. Petricevic, A. Beck, P. Wang, H. Scheller, and J. Fricke1995 Relationship Between Optical Transparency and Nanostructural Features of Silica Aerogels. Journal of

Non-Crystalline Solids 185: 240-248.Beck, A., W. Koerner, and J. Fricke1994 Optical investigations of granular aerogel fills. Journal of Physics. D, Applied Physics 27: 13-18.Hotaling, S. P.1993 Ultra-Low Density Aerogel Optical Applications. Journal of Materials Research 8: 352-355.Emmerling, A., P. Wang, G. Popp, A. Beck, and J. Fricke1993 Nanostructure and Optical Transparency of Silica Aerogels. Journal De Physique Iv 3: 357-360.Platzer, W. J., and M. Bergkvist1993 Bulk and surface light scattering from transparent silica aerogel. Solar Energy Materials and Solar Cells 31: 243-251.Wang, P., W. Korner, A. Emmerling, A. Beck, J. Kuhn, and J. Fricke1992 Optical Investigations of Silica Aerogels. Journal of Non-Crystalline Solids 145: 141-145.Beck, A., O. Gelsen, P. Wang, and J. Fricke1989 Light Scattering For Structural Investigations of Silica Aerogels and Alcogels. Journal De Physique 50: C4203-C4208.Lampert, C. M.1987 Advanced optical materials for energy efficiency and solar conversion. Sol. Wind Technol. 4: 347-379.Hunt, A. J., and P. Berdahl1984 Structure data form light scattering studies of aerogel. Mater. Res. Soc. Symp. Proc. : 275-280.Lampert, C. N.1983 Solar optical materials for innovative window design. Int. J. Energy Res. 7: 359-374.

MECHANICAL PROPERTIESHunt. A.J., and Ayers, M.R.2001 Investigations of Silica Alcogel Using Coherent Light. Journal of Non-Crystalline Solids, 285:162-166.Woignier, T., J. Phalippou, H. Hdach, G. Larnac, F. Pernot, and G. W. Scherer1992 Evolution of Mechanical Properties During the Alcogel Aerogel Glass Process. Journal of Non-Crystalline Solids 147: 672-680.Armand, A. C., and D. Guyomar1992 Acoustic and Mechanical Characterization of Silica Aerogels. Journal De Physique Iii 2: 759-762.Hdach, H., T. Woignier, J. Phalippou, and G. W. Scherer1990 Effect of Aging and pH On the Modulus of Aerogels. Journal of Non-Crystalline Solids 121: 202-205.Woignier, T., and J. Phalippou1989 Scaling Law Variation of the Mechanical Properties of Silica Aerogels. Journal De Physique 50:C4179-C4184.

Phalippou, J., T. Woignier, and R. Rogier1989 Fracture Toughness of Silica Aerogels. Journal De Physique 50: C4191-C4196.Cross, J., R. Goswin, R. Gerlach, and J. Fricke1989 Mechanical Properties of SiO2 - Aerogels. Journal De Physique 50: C4185-C4190.

CHERENKOV RADIATION COUNTER APPLICATIONSAdachi, I., T. Sumiyoshi, K. Hayashi, N. Iida, R. Enomoto, K. Tsukada, R. Suda, S. Matsumoto, K. Natori, M. Yokoyama, and H. Yokogawa1995 Study of a threshold Cherenkov counter based on silica aerogels with low refractive indices. Nuclear Instruments and Methods in Physics Research, Section A 355: 390-398.Ganezer, K. S., W. E. Keig, and A. F. Shor1994 A simple high efficiency Cherenkov counter. IEEE Transactions on Nuclear Science 41: 336-342.Hasegawa, T., O. Hashimoto, T. Nagae, and M. Sekimoto1994 A large silica aerogel Cherenkov counter for SKS. Nuclear Instruments and Methods in Physics Research, Section A 342: 383-388.Brajnik, D., S. Korpar, G. Medin, M. Staric, and A. Stanovnik1994 Measurement of Sr-90 Activity With Cherenkov Radiation In a Silica Aerogel. Nuclear Instruments &Methods In Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment353: 217-221.Fields, D. E., H. Vanhecke, J. Boissevain, B. V. Jacak, W. E. Sondheim, J. P. Sullivan, W. J. Willis, K.Wolf, E. Noteboom, P. M. Peters, and R. Burke1994 Use of Aerogel For Imaging Cherenkov Counters. Nuclear Instruments & Methods In Physics Research Section a-Accelerators Spectrometers Detectors and Associated Equipment 349: 431-437.Adachi, Ichiro1994 R and D on Cherenkov counter based on silica aerogel with low refractive index. Hoshasen 20: 21-30.Lippert, C., R. Siebert, J. P. Didelez, J. Ernst, R. Frascaria, J. Y. Martel, and R. Skowron1993 Particle discrimination in medium energy physics with an aerogel Cherenkov detector. Nuclear Instruments and Methods in Physics Research, Section A 333: 413-421.Onuchin, A., A. Shamov, Yu Skovpen, A. Vorobiov, A. Danilyuk, T. Gorodetskaya, and V. Kuznetsov1992 The aerogel Cherenkov counters with wavelength shifters and phototubes. Nuclear Instruments and Methods in Physics Research, Section A 315: 517-520.Miskowiec, D., W. Ahner, E. Grosse, P. Senger, and W. Walus1990 Aerogel Cherenkov detectors for the Kaon spectrometer. Verhandlungen der Deutschen Physikalischen Gesellschaft 25: 1520.Vincent, P., R. Debbe, A. Pfoh, and M. Abreu

1988 E802 aerogel Cherenkov detector. Nucl. Instrum. Methods Phys. Res. 272: 660-668.Carlson, P.1986 Aerogel Cherenkov counters: Construction principles and applications. Nucl. Instrum. Methods Phys. Res. 248: 110-117.Poelz, G.1986 Aerogel Cherenkov counters at DESY. Nucl. Instrum. Methods Phys. Res., Sect. A. 248: 118-129.Kawai, H., J. Haba, T. Homma, M. Kobayashi, K. Miyake, T. S. Nakamura, N. Sasao, Y. Sugimoto, M. Yoshioka, and M. Daigo1985 Tests of a silica aerogel Cherenkov counter. Nucl. Instrum. Methods Phys. Res., Sect. A 228: 314-322.Maurer, K., G. Koebschall, K. Roehrich, C. Schmitt, and V. H. Walther1984 Silica aerogel threshold Cherenkov counters for use at intermediate energies. Nucl. Instrum. MethodsPhys. Res., Sect. A 224: 110-111.Fernandez, C., K. E. Johansson, M. Schouten, S. Tavernier, P. Ladron de Guevara, P. Herquet, J.Kesteman, and O. Pingot1984 Performance of the silica aerogel Cherenkov detector used in the European Hybrid Spectrometer. Nucl. Instrum. Methods Phys. Res., Sect. A 225: 313-318.Yasumi, Shinjiro, and Hideyuki Kawai1983 Silica aerogel Cherenkov counter. Nippon Butsuri Gakkaishi 38: 671-676.Poelz, G., and R. Riethmueller1982 Preparation of silica aerogel for Cherenkov counters. Nucl. Instrum. Methods Phys. Res. 195: 491-503.Carlson, P. J., K. E. Johansson, J. Norrby, J. Kesteman, O. Pingot, S. Tavernier, and L. van Lancker1982 Tests of an 18 module silica aerogel Cherenkov detector to be used in the European hybrid spectrometer. Nucl. Instrum. Methods Phys. Res. 192: 209-216.Burkhardt, H., P. Koehler, R. Riethmueller, B. H. Wiik, R. Fohrmann, J. Franzke, H. Krasemann, R. Maschuw, G. Poelz, and J. Reichardt1981 TASSO gas and aerogel Cherenkov counters. Nucl. Instrum. Methods 184: 319-331.Trachsel, C., D. Perrin, and R. Schwarz1981 Study of an aerogel Cherenkov detector with indirect light collection. Helv. Phys. Acta 53: 655-661.de Brion, J. P., A. Caillet, J. B. Cheze, J. Derre, G. Marel, E. Pauli, and C. Pigot1981 Silica aerogel Cherenkov counter in a missing-mass experiment K/sup -/d ..-- >.. K/sup +/ + X at 1.4 GeV/c. Nucl. Instrum. Methods 179: 61-65.Carlson, P. J., K. E. Johansson, J. Kesteman, O. Pingot, J. Norrby, S. Tavernier, F. van den Bogaert, andL. van Lancker1979 Increased photoelectron collection efficiency of a photomultiplier in an aerogel Cherenkov counter. Nucl. Instrum. Methods 160: 407-410.Bourdinaud, M., J. B. Cheze, and J. C. Thevenin

1976 Use of silica aerogel for Cherenkov radiation counter. Nucl. Instrum. Methods 136: 99-103.

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ZERO-GRAVITY AEROGEL FORMATION:The Effects of Reduced Gravity on the Clarity and Pore Structure of Aerogels Produced by a Rapid Gelation Two-Step Catalysis

Test Equipment Data PackageStephen SteinerPrincipal InvestigatorZero-G Aerogel TeamProject ID: 2002-073University of Wisconsin–MadisonChemistry Department1101 University Ave.Madison, WI 53706-1396March 6, 2002Quick Reference SheetPrinciple Investigator: Stephen SteinerContact Information:Mailing Address 1001 W. Brentwood Lane Glendale, WI 53217Phone (414) 732-5261 (Mobile)Email mailto:ssteiner@zerogaerogel.comExperiment Title: Zero-Gravity Aerogel Formation: The Effects of Reduced Gravity on the Clarity and Pore Structures of Aerogels Produced Through a Rapid Gelation Two- Step CatalysisFlight Dates: Tuesday, April 23rd and Wednesday, April 24th 2002Overall Assembly Weight: 190 lbs.Assembly Dimensions (L x W x H): 22" x 21" x 51"Proposed Floor Mounting Strategy: StrapsGas Cylinder Requests: NoneOverboard Vent Requests: NoPower Requirements: 115 VAC, 9.4 Amps maxFlyer Names for Each Proposed Flight Day: Tuesday WednesdayStephen Steiner David MeisterLucas Heinkel Nicholas KhoTable of ContentsQuick Reference Sheet 14. Flight Manifest 45. Experiment Background 55.1 Introduction 55.2 Preparation of Alcogels 65.3 Supercritical Extraction Process 75.4 Rayleigh Scattering in Silica Aerogels 85.5 Effects of Gravity on the Formation of Aerogel 85.6 Other Reduced Gravity Experiments 95.7 Uses of Aerogel 105.8 Experimental Objectives 105.9 Description of Follow-up Flight 116. Experiment Description 126.1 Expectations of Experiment 126.2 Expectations of Corresponding Ground Experiments 137. Equipment Description 147.1 Introduction 14

7.2 Containment Unit 147.3 Glassware 167.4 Glassware Controls and Sensors 167.5 Computer Controls 197.6 Molds 207.7 Liquid Containment and Delivery 208. Structural Analysis 228.1 Overview 228.2 Centers of Gravity 228.3 Summary 288.4 Structural Integrity 289. Electrical Analysis 309.1 Electrical Schematic 309.2 Load Analysis 319.3 Emergency Shutdown Procedures 3110. Pressure Vessel Certification 3210.1 Schematic 3310.2 MAWP Table 3411. Laser Certification 3512. Parabola Details and Crew Assistance 3613. Free Float Requirements 3714. Institutional Review Board 3815. Hazard Analysis Report 3916. Tool Requirements 5217. Photo Requirements 5318. Aircraft Loading 5419. Ground Support Requirements 5520. Hazardous Materials 5621. Material Safety Data Sheets 5722. Procedures 8022.1 Shipping Equipment to Ellington Field 8022.2 Ground Operations 8022.3 Loading 8022.4 Pre-Flight 8022.5 In-Flight 8022.6 Post-Flight 8123. Bibliography 82Figure 5-1: Silica Aerogel on a Hand 5Figure 5-2: Silica Aerogel on a Penny 5Figure 5-3: Steel Supercritical Drying Vessel 7Figure 7-1: Containment Unit Inner and Outer Boxes 15Figure 7-2: Glassware and Pipetting Apparatus 15Figure 7-3: Syringe-Molds 17Figure 7-4: Laser Diode Photocell Assembly Across Zypette 18Figure 7-5: Motor and Gear Assembly for Moving Microstopcock 18Figure 7-6: Contacts on Microstopcocks 19Figure 7-7: Liquid Delivery and Containment (not shown with sensors) 21

Figure 8-1: Showing center of gravity of entire system (outer case, inner case, internal components). 24Figure 8-2: Total Structure from Side 24Figure 8-3: Total Structure Under G-Load Conditions (Front) 25Figure 8-4: Inner Box Under G-Load Conditions (Side) 25Figure 8-5: Inner Box Under G-Load Conditions (Front) 26Table 8-1: Summary of calculated factors of safety for fastening of the equipment under all g-load specifications 28Table 8-2: Induced G-Loads and Factors of Safety 29Figure 9-1: Electrical Schematic 30Table 9-1: Load Table 31Table 18-1: Weight Table 544. Flight ManifestStephen SteinerFlight Date: Tuesday, April 23rdPrevious Flights: July 2001Lucas HeinkelFlight Date: Tuesday, April 23rdPrevious Flights: NoneDavid MeisterFlight Date: Wednesday, April 24thPrevious Flights: NoneNicholas KhoFlight Date: Wednesday, April 24thPrevious Flights: NoneAlternateMichael FidlerFlight Date: As NeededPrevious Flights: None5. Experiment Background5.1 INTRODUCTIONAerogel is a low-density, nanoporous, polymer solid that is typically 50-99% air. It is formed by extracting the liquid solvent from a gel in such a way that the gel's solid component is left behind without collapsing due to capillary action. The remaining solid component retains most or all of the gel's original volume. This solid material is aerogel.A gel is a colloidal system in which a network of interconnected solid particles spans the volume of a liquid medium. If the liquid solvent in a gel is evaporated, the gel's solid particle matrix will collapse by capillary forces and form a dense glass-like polymer. It is possible, however, to extract the liquid from a gel without causing the matrix to collapse. This is typically done by supercritically extracting the liquid from the gel. The result is a low-density solid polymer in the shape of the original precursor gel. This solid is aerogel.Figure 5-1: Silica Aerogel on a Hand Figure 5-2: Silica Aerogel on a PennyThe most heavily researched type of aerogel is silica aerogel. Silica aerogels are typically transparent with a distinct bluish tint. Their densities range from 0.1 g/cc to 0.001 g/cc and, as previously mentioned, are 50-99% air. Although aerogels are

extremely low in density, they can withstand 500 to 4,000 times their weights in applied force. In addition, silica aerogels have very high internal surface areas, ranging from 250 m2/g to 4,000 m2/g.Because of their low densities and high surface areas, aerogels also have unusual thermal, electrical, and insulative properties. Silica aerogel is the best thermally insulating material that has ever been produced, and because of this, has been used by NASA as lightweight insulation for spacecraft. Aerogel could potentially be used as superinsulating window inserts for industry, commercial, and aerospace applications. Although silica aerogel is transparent, its noticeable blue color prevents it from being used in such applications. In addition to its lengthy processing times and high cost of production, aerogel is not currently commercially practical.5.2 Preparation of AlcogelsThe physical and chemical properties of aerogel are determined during the formation of the aerogel precursor gel, called alcogel. Alcogel is typically formed by the sol-gel process. In this process, a solution of monomer molecules begins to react to form oligomeric species (prepolymer particles) by a chemical reaction. This solution of oligomeric species is called a sol. As the chemical reaction continues, these oligomeric particles become larger and eventually interconnect. The polymerization of these particles results in the formation of a solid particle matrix in the solvent and eventually forms a gel. The manner in which these oligomeric species interconnect defines the pore structure of the derivative aerogel.Moreover, the amount of solvent present in the solution will determine the density of the derivative aerogel.The overall reaction by which the formation of the gel occurs is shown below (1,2). Silica alcogel is typically formed by hydrolyzing a silicon alkoxide with water and polymerizing the partially hydrolyzed species by condensation reactions.

nMe(OR)4 + 4nH2O nMe(OH)4 + 4nROH Hydrolysis (1)

nMe(OH4) nMeO2 + 2nH2O Condensation (2)R=alkyl group (like C2H5), Me=metal (like silicon)The sol-gel polymerization has three steps--hydrolysis, alcohol condensation, and water condensation. These three reactions form siloxane bonds from hydrolyzed alkoxide molecules, eventually forming a polymer across the liquid medium.MeOR + HOH MeOH + ROH Hydrolysis (3)MeOR + HOMe MeOMe+ ROH Alcohol Condensation (4)MeOH + HOSi MeOMe+ HOH Water Condensation (5)

5.3 Supercritical Extraction ProcessOnce an alcogel has been formed, it is usually soaked in a pure organic solvent to remove any excess reagents and catalyst from the gel. This solvent must be miscible with polar and non-polar solvents, since both are present in the alcogel. After an alcogel has been adequately diffused with the pure organic solvent, it is placed inside a high-pressure vessel and soaked several more times in liquid carbon dioxide. Most organic solvents (like ethanol) have high critical points and

are extremely flammable at those conditions. Instead, a solvent exchange with liquid CO2 can be utilized.The CO2 solvent exchange reduces the risk of explosion associated with the high critical points of organic solvents. Carbon dioxide has the benefits of being non-flammable, miscible with organics, and having a low critical point of 31.1°C at 75 atmospheres. For the solvent exchange to succeed, the alcogel must be soaked in liquid CO2 long enough for the CO2 to completely diffuse through the gel and take the place of the organic solvent. At that point, the CO2 can be brought to supercritical temperatures and pressures for solvent extraction.After the gel has been Figure 5-3: Steel Supercritical Drying Vessel completely diffused with CO2, (A Manuclave) it can be supercritically dried. This process is done by heating the gel past its solvent's critical pointthe temperature and pressure beyond which a substance cannot be condensed into a liquid by increasing pressure. For CO2, this is done by heating the alcogel past 31.1°C and 1,050 psi.Supercritical fluids are semi-liquids/semi-gases that possess some properties similar to those of gases (such as expansion) and other properties like liquids (such as viscosity). By heating the gel to its solvent's critical point, the solvent can be extracted from the gel as a supercritical fluid without causing the gel's solid particle matrix to collapse. Once the solvent has diffused out of the gel, the vessel is depressurized, the gaseous solvent vented off, and the newly formed aerogels can be taken out.5.4 Rayleigh Scattering in Silica AerogelsIt has been proposed that formation of aerogel in microgravity could allow for the production of non-blue aerogels. The blue color aerogels show is a result of Rayleigh scattering of white light as it passes through the aerogel's nanopores. These nanopores, sized from 5 to 15 nm across, are much smaller than the wavelengths of visible light, yet large enough to act as particles for Rayleigh scattering. The larger of these pores scatter light more easily, and are thus responsible for the blue color in the aerogel. Shorter wavelengths are diffracted more than longer wavelengths, and therefore blue and violet light are diffracted the most. Although both blue and violet light are diffracted by these nanopores, only a blue color is seen. This is because the human eye is more sensitive to blue light than any other color, and so the violet light scattered by the aerogel is perceived to be mostly blue.5.5 Effects of Gravity on the Formation of AerogelThe effect of gravity is usually negligible in systems affected only by Brownian motion; however, as a solution begins to polymerize, oligomeric species with considerable mass are formed, and can be affected by the force of gravity through buoyancy.The polymerization process in the formation of a sol is random, and thus the weights of the oligomeric species (which will later polymerize to form the gel) can vary considerably. Heavier oligomers have lower buoyancies, and thus, are affected by gravity more than lighter species. This does not mean that heavier oligomers sink to the bottom of the gel, but rather that they are not affected solely by Brownian motion. The influence of gravity on the buoyancies of oligomeric species in the sol prevents uniform interconnection during gelation. This non-

uniform polymerization in the gel causes the formation of larger nanopores throughout the gel due to a downward bias of gravity on the heavier oligomeric species.The downward push of gravity on the forming gel also causes a "Venetian blind" effect, observed by the fact that alcogels are more opaque through the side (looking at the Venetian blinds) then through the top (looking down through them).Previous studies of the effects of microgravity on the formation of silica alcogels have been inconclusive. Lawrence Berkeley under the direction of Arlon Hunt reported that aerogels formed in microgravity show higher surface areas and different pore structures than aerogels formed in 1 G of gravity, but not necessarily more or less blue in color.5.6 Other Reduced Gravity ExperimentsExperiments aboard the space shuttle utilized a slow gelation process to form alcogels in zero-gravity, which were then brought to Earth and analyzed. The first mission produced inconclusive results because of human and experimental error. The second mission did not produce any aerogels, but silica Stober particles (microscale alcogels) for pore structure analysis. The long gel times required to produce silica alcogel mean that testing the effects of microgravity on its formation require an environment where zero-gravity is sustainable for several hours.Arlon Hunt did an experiment aboard the KC-135A analyzing the species in a silica sol by X-ray scattering techniques. He found a difference in the formation of pre-gel silica clusters that led him to do an experiment forming alcogel aboard a Saturn V rocket a year later. The results showed that the lack of gravity affected the formation of aerogel in such a way that it may be possible to make it completely transparent if grown in zero-gravity. The Saturn V and KC-135A experiments were limited to short amounts of time--too short for the formation of a substantial alcogel sample, only long enough to produce pre-gel sols. These sols showed different light scattering properties than those produced in 1 G of gravity, and so microgravity would most likely also influence the formation of gels in similar settings.The formation of silica alcogel on a Saturn V rocket or the KC-135A was not practical, however, since an extremely rapid gel time would be required.5.7 Uses of AerogelAerogel is currently only commercially available on a limited scale. Although it has many potential applications including superinsulating window inserts, its noticeable bluish tint and high cost of production prevent it from being commercially viable. Aerogel has been used by NASA on various spacecraft including Stardust and several Mars probes to collect high-velocity micrometeorites in outer space.In order for aerogel to become a commercially viable product, several issues must be addressed.First, there must be a way to reduce the Rayleigh scattering in silica aerogel so that it can be made optically transparent.Second, there must be an inexpensive way to make it transparent. Currently, there is no completely effective way of making clear silica aerogels.5.8 Experimental ObjectivesThe objective of the experiment is to test if the absence of gravitational pull on forming alcogels will have an influence on the pore structure of the resulting

aerogels. For silica aerogels, a more uniform pore structure may improve the clarity of the derivative aerogel, possibly to the point where most of the Rayleigh scattering in the aerogel could be eliminated.The experiment is testing if reduced gravity can allow for an increase in surface area in the resulting aerogels, and if so, by how much.In addition to these objectives, we will be testing the effectiveness of microgravity as a dispersion technique for embedding solid materials into aerogel matrices, for the production of composite silica aerogels. We will be embedding iron, palladium, and buckminsterfullerenes into several alcogels and will evaluate their uniformity in comparison with composite aerogels formed by other techniques.5.9 Description of Follow-up FlightThis experiment is our second attempt at forming aerogels in reduced gravity on board the KC-135A. We have made numerous modifications and several complete redesigns to our previous experiment, which was flown in July 2001.6. Experiment DescriptionThe experiment is testing the effects of reduced gravity on the formation of the silica matrix of silica alcogels. This is done by mixing two liquids in reduced gravity that form a gel upon being mixed. The liquids will be set to gel within 15 to 20 seconds after being mixed and, once the gel has solidified, the gel will remain unaffected by reduced or induced gravity for the rest of the flight.The two liquids required to form the alcogels are a base solution of tetramethoxysilane, ethanol, and water and a catalyst solution of ethanol and ammonium hydroxide. The volume of ammonium hydroxide in the catalyst solution may vary from 50 to 100%, and will be added in 15 M concentration.For each flight, 18 gels will be produced. The gels will then be taken back to the ground and stored under ethanol in a sealed plastic container for shipment back to the University of Wisconsin. The gels will then be supercritically dried and analyzed. Analysis will be done using spectrophotometry, surface area measurements, density measurements, tensile strength analysis, and compressive modulus analysis.In some of the gels for both flights, the molds will contain a small amount of a fluorescent dye, palladium metal, iron metal, or buckminsterfullerenes. This is to form composite alcogel materials by using microgravity to disperse solid particles throughout the alcogel precursor liquid, allowing it to be trapped and evenly dispersed throughout the alcogel when it forms. Doing so will illustrate the dispersion process of liquids and solids in our gel apparatus and trap the dispersion in a gel. In addition, a number of composite aerogel materials will be produced.6.1 Expectations of ExperimentThe expectations of the experiment are that aerogels produced in microgravity will show reduced scattering the blue-violet region of the spectrum compared with aerogels produced in 1 G. We believe that between 30 and 36 alcogels of various types will be safely and effectively formed in reduced gravity. It is also believed that these gels will form within 5 to 15 seconds, which will be 5 seconds faster than the target gel times that will be observed in 1 G.The main objective of the experiment is to test to see if the pore structures of such gels will be different than similar gels produced in 1 G. It is believed that analysis of

these gels will show them to be of significantly higher surface area than aerogels produced in 1 G, as well as being more transparent (less blue) than silica aerogels produced in 1 G.These differences are expected to result in aerogels with surface areas between 1,000 m2/g to 2,000 m2/g higher, with more even nanoporosities and narrower distributions of pore sizes, focused mainly between 5 to 15 nm.More even nanoporosity in the silica alcogels may result in a reduction in the visible effects of Rayleigh scattering in the resulting aerogels. It is believed that aerogels produced in reduced gravity will have densities similar to aerogels produced on the ground.In addition to these expectations, it is also believed that composite alcogels of silica and other materials can be formed with a microscopically even dispersal of material throughout the gel.6.2 Expectations of Corresponding Ground ExperimentsAerogels produced on the ground in the same manner are expected to have surface areas of 500 m2/g to 2,500 m2/g, with nanoporosities typical of normal aerogels and a broad distribution of pore sizes, from 5 to 65 nm.7. Equipment Description7.1 IntroductionThe equipment in the experiment is used to pipette specific amounts of catalyst solution into cylindrical glass molds that have been pre-filled (before the zero-g flight) with base solution. The catalyst and base react in zero-g to form a gel in the mold. The apparatus is designed to prevent and eliminate air bubbles in the gels by using syringes, collapsible bags, and rubber o-ring sealed molds to handle the liquids, allowing for liquid-tight reactions. The apparatus is computer controlled to minimize human error and to minimize risk in breaking equipment due to mishandling in zero-g.Figure 7-1: Containment Unit Inner and Outer Boxes7.2 Containment UnitThe equipment used in the experiment is housed in a glove box made of aluminum frame and polycarbonate windows. The box consists of an inner glove box nested in a larger glove box (see Figure 7-1) giving two solid, global layers of protection around our apparatus. The glassware is our first layer of protection.Figure 7-2: Glassware and Pipetting ApparatusThe inner aluminum-polycarbonate box is vibrationally isolated from the outer box by 1.5 to 2.5 inches of damping foam on the bottom of the outer box and on all corners. This foam protects the gelation reaction from low frequency vibrations caused by the KC-135A and by the environment around the boxes.The boxes are equipped with gloves to allow for manipulation of objects (such as molds) in the box. The inner box is equipped with butyl dry-box gloves, which are chemically resistant to all chemicals being used in the system. The outer box gloves, which fit into the inner box gloves, are made of neoprene and lined with cotton.The inner box top is lined with two layers of 1/8" rubber and locked shut with Nylon buckles. The outer box is also lined with rubber and locked shut with steel latches on the front of the box. The lids are not airtight but can contain a liquid spill or glass break.

7.3 GlasswareThe apparatus housed by the boxes consists of a modified gas-tight borosilicate syringe, called a zypette (a zero-gravity syringe-pipette, see Figure 7-2). The zypette is used to measure out specific amounts of liquid for dispensing catalyst into the molds. The zypette is connected to a borosilicate 4-way connection called a "micro-t," to allow for three-way direction of the liquid flow. The micro-t is encased in epoxy for structural support. Both the zypette and micro-t were professionally manufactured.The micro-t has three microstopcocks that branch from it, each connected to a Luer lock to allow for attachment of needles to the zypette. On one connection of the micro-t is connected a Mylar bag filled with catalyst. On another connection, an empty Mylar bag is connected for dumping and flushing of waste. The third connection is an open Luer lock to allow for a mold equipped with a Luer needle (see Figure 7-3) to be attached to the apparatus.7.4 Glassware Controls and SensorsThe zypette is operated by a 25-lb. actuator that pushes and pulls the zypette piston up and down to aspirate and dispense liquid as instructed. The amount of liquid in the zypette is monitored by a set of 3 laser diode/photocell assemblies, placed at the 0 mL, 2.5 mL, and 5 mL positions on the zypette (see Figure 7-4). The assemblies are connected to a computer which interprets the status of the photocells (exposed to light or blocked by the piston) to determine the height of the piston and the volume of the liquid in the zypette. The laser/photocell assemblies are made ofFigure 7-3: Syringe-Molds polycarbonate and shielded by opaque plastic to prevent laser light from shining outside of the assembly.The microstopcocks are opened and shut by 12VDC motors, turning the handles of the microstopcocks by a gear mechanism (see Figure 7-5). The motors are controlled by the computer. Two aluminum contacts placed on the handles and bases of the microstopcocks connect when the microstopcocks are open, instructing the computer the stopcock is open. When the contacts do not touch, the stopcock is closed and the circuit is broken (see Figure 7-6).The actuator is operated by two circuits that are controlled by the computer, a push circuit that supplies positive voltage to the actuator and aFigure 7-4: Laser Diode Photocell Assembly Across ZypetteFigure 7-5: Motor and Gear Assembly for Moving Microstopcock pull circuit that supplies negative voltage to the actuator (see Electrical Analysis).7.5 Computer ControlsThe glassware is operated by three motors and an actuator that are controlled by optically isolated relay circuits interfaced with the parallel port of the computer. The computer runs a program called ZGel, written by our team, that has subroutines designed to operate the glassware with composite functions. For example, the computer can be instructed to inject liquid into a Figure 7-6: Contacts on Microstopcocks mold by aspirating 5 mL, waiting 2 seconds, and dispensing it in small bursts, which involves several separate mechanical steps, like opening stopcocks and pulling the actuator. The program has built-in safety controls, for example, preventing the actuator from operating when all microstopcocks are closed, to prevent pressure build-up or strain (see Figure 7-6). If the computer

malfunctions, the system can be switched to manual mode, which relies on a panel of switches located inside the inner box connected in parallel to the optical relays that power the devices. These switches perform individual functions such as opening motors and moving the actuator arm, but not composite functions.If power fails to the system, the experiment is not operated.7.6 MoldsThe gelation reaction is carried out by injecting 2.5 or 5.0 mL of catalyst into molds pre-filled with base (prior to the flight). The molds are glass cylinders clamped shut with glass plates and sealed by rubber gaskets, equipped with Nylon syringes that expand when liquid is injected, to accommodate for the volume of liquid. The molds are housed in a plastic shelving unit that contains 18 boxes, fitted with foam cutouts for the molds to rest in. The drawers are snapped into place with a magnetic snap.7.7 Liquid Containment and DeliveryLiquid reagents used for the experiment are kept in 30 mil, 500 mL Mylar bags with special septum seals. The septum seal is comprised of a Nylon gasket epoxied to the inside of the Mylar bags, sandwiched against a second Nylon gasket epoxied to the outside of the Mylar bag (see Figure 7-7). Through the gaskets is epoxied and sealed a 0.25"-diameter 3"-long PTFE tube. To the top of the tube is a rubber septum sealed in place. The liquid reagent is introduced and extracted from the Mylar bag by injection with a syringe needle.Liquid is pulled out of the bags by steel needles connected to the micro-t, by the slight pressure differential caused by the actuator pulling the zypette piston upwards. Liquid is injected into the bags by the actuator pushing down. Two bags are used for the experiment–a catalyst source bag and a waste bag. The bags are secured in aluminum boxes and strapped in place with Velcro straps. Two straps that strap over the top of the bag, two straps secure it to a side of the aluminum box, and one strap secures it to the bottom.Figure 7-7: Liquid Delivery and Containment (not shown with sensors)8. Structural AnalysisStructural analysis of all components involved revealed that the apparatus is sufficiently designed to withstand all g-load specifications required by NASA. First, calculations of g-loads of the entire system are discussed showing that the apparatus is securely fastened to the fuselage of the KC-135A. Next, calculations are presented showing that all internal components will be isolated from the cabin of the aircraft via the outer case. Free-body diagrams (FBDs) are included for each calculation. Factors of safety for all critical components show that the equipment built for this experiment is safe for all persons and aircraft components.8.1 OverviewTwo cases, one outer and one inner separated by a layer of energy-absorbing foam, are used to provide containment for chemicals in the experiment. Internal glass, Mylar, and cell (mold) components provide the third layer of containment. The frames for the outer and inner case are made of aluminum L-beams ("angles"). The L-beams are 1/8" thick, 90o bend, with 1½" legs. Sides of each case are made of ¼" polycarbonate sheets bolted to the aluminum L-beams with ¼" steel bolts. The upper lids of each case are made of 1/8" polycarbonate sheets with hinges attached by 5/16" steel bolts. The bottoms of each case consist of ¼"

aluminum sheets. The outer case is attached to the fuselage of the aircraft with two 2"-wide cargo straps and 3/8" steel bolts.8.2 Centers of GravityThe entire system has left-right and front-back symmetry. All calculations for the centers of gravity use a 3-D right-handed coordinate system with the "origin" located at the bottom-left-rear corner of the outer case. To calculate the centers of gravity (CG), we used individual component weights and positions relative to the origin. For the structural analysis, we calculated two CGs: one for the inner case containing all inner components and one for the entire system.The total weight (at 1g) of the inner box with internal components is 80 lbs. The total weight of the internal components is less than 10 lbs. We will assume this weight to be concentrated at the CG of the inner box due to relatively symmetrical weight distribution among the internal components. The outside edges of the inner case have dimensions 19" x 49" x 17" (x, y, z l, h, w). After considering left-right and front-back symmetry and the 1½" foam layer between the inner and outer cases, we can see that the CGx and CGz of the inner case with all internal components are located at 11 (19/2 + 1.5) and 10 (17/2 + 1.5) inches, respectively. CGy is a slightly more complicated calculation. The inner case has an aluminum sheet 1" from the bottom as well as an aluminum sheet 10" from the bottom that serves as a shelf for the internal components of the experiment. Each aluminum sheet weighs 8 lbs. CG in the vertical direction is calculated as follows:CGy = [24.5*64 + 10*8 + 1*8] / 80 + 1.5 (foam) = 22.2"Hence, the CG of the inner case with all internal components is (11, 22.2, 10).The center of gravity of the entire apparatus is required for calculations to show that the equipment will be securely fastened to the aircraft under all g-load specifications. The weight of the outer case including foam is 81 lbs.CGx for the outer case alone is 22.75/2 = 11.4 inches. CGz for the outer case is 21/2 = 10.5 inches. CGy for the outer case, with an 8-lb bottom aluminum plate is [25.5(81-8) + 1(8)] / 81 = 23 inches. Below are the calculations of the CG for the entire system (i.e., outer box + inner box + internal components):CGx = [11*80 + 11.4*81] / 161 = 11.2"CGy = [22.2*80 + 23*81] / 161 = 22.6"CGz = [10*80 + 10.5*81] / 161 = 10.3"Here we can see that the center of gravity for the entire system is located at (11.2, 22.6, 10.3). The weight of the equipment will be assumed to be concentrated at the center of mass for all moment and factor of safety calculations.Figure 8-1: Showing center of gravity of entire system (outer case, inner case, internal components).Figure 8-2: Total Structure from Side (Note: Straps extend behind handle over box)Figure 8-3: Total Structure with Center of Gravity (Front)Figure 8-4Figure 8-59-g's ForwardUnder an induced gravity of 9-g's forward, the entire system will experience a weight of 1449 lbs.

(161*9). The reaction force to this weight in the horizontal direction will be provided by the two-2" wide cargo straps attached to the handle of the outer case (bolted to the aircraft via 3/8" steel bolts). Summing the forces in the x-direction we can see that the straps will each need to provide a reaction force of 725 lbs in the negative x-direction. Each strap is capable of supplying 5000*cos(58o) = 2650 lbs. This results in a factor of safety of 3.66 for the entire apparatus in 9-g's forward in the horizontal direction. Taking the moments about the point (0, 0, 10.3) we can see that the reaction moment for each strap will need to be 1449*22.6 / 2 = 16400 lb-in. The straps are each capable of providing a moment of 5000*sin(58) * 18.5 = 78400 lb-in. This results in a factor of safety of 4.78. We can see that the equipment will remain static under 9-g's forward.3-g's AftUnder an induced gravity of 3-g's aft, the entire system will experience a weight of 483 lbs.(161*3). The reaction force to this weight will be provided by the two-2" wide cargo straps attached to the handle of the outer case (bolted to the aircraft via 3/8" steel bolts). Summing the forces in the x-direction we can see that the straps will each need to provide a reaction force of 242 lbs in the positive x-direction. Each strap is capable of supplying 5000*cos(58o) = 2650 lbs.This results in a factor of safety of 11.0 in the horizontal direction for the entire apparatus in 3-g's aft. Taking moments about the position (22.75, 0, 10.3) we can see that each strap will need to provide a reaction moment of 483*22.6 / 2 = 5460 in-lbs.. Each strap is capable of supplying a 5000*sin(58)*18.5 = 78400 in-lbs.. This results in a factor of safety of 14.3.6-g's DownWhile experiencing an induced gravity of 6-g's down, the equipment will experience an induced weight of 966 lbs. The area of the bottom of the equipment is 3.32 ft^2. This results in a stress of 291 lbs/ft^2.This exceeds the acceptable in-flight floor loading specification of 200 lbs/ft^2. Hence our experiment will need to be provided floor shoring of at least 5 square feet to satisfy the g-load specifications in the 6'g's down situation.2-g's LateralThe equipment will experience an induced weight of 322 lbs. in the lateral direction. To avoid translational motion in the z-direction, the outer case will need to be ratcheted down with enough force so that the frictional force generated against the foam is significantly greater than the 322 lbs. of induced force. If the case were to rotate, the cargo straps would need to counter the moment induced about the position (11.4, 0, 0). The moment that needs to be countered would be 322*22.6 = 7,300 lb.-in. The tether strap going over the top of the outer case would need to provide a force of 7,300 / 21 = 350 lbs. Since the strap is capable of providing a force of up to 5,000 lbs., the factor of safety for 2'g's in the lateral direction would be 14.3.2-g's UpUnder an induced gravity of 2'g's, the weight of the equipment would be 322 lbs. This weight will be countered by reaction forces provided by the straps over the top of the outer case. Each strap is capable of providing up to 5000 lbs. of reaction force when in tension.This results in a factor of safety of 5000*2 / 322 = 31.

8.3 SummaryAll of the calculations for the entire system used in the formation of aerogel will remain in static equilibrium for all g-load specifications. The use of two cargo straps will provide sufficient reaction forces to secure the apparatus to the fuselage of the KC-135A.Table 8-1: Summary of calculated factors of safety for fastening of the equipment under all g-load specifications.Forces and moments shown are the reactions that need to be provided by one cargo strap.Case Force (lbs.) Force FS Moment (lb-in.) Moment FS9 g's forward 725 3.66 16400 4.783 g's aft 242 11 5460 14.36 g's down 966 on aircraft floor see text N/A N/A2 g's lateral Need more info see text 7300 14.32 g's up 161 31 N/A N/A8.4 Structural IntegrityUnder an induced acceleration, the outer box will contain all components within it and not come apart or deform. We intentionally over-engineered the outer box so that it could safely contain everything within it. The shear strength for polycarbonate is 7,000 psi. The area being stressed is 0.196 in2. If the entire mass of the inner box applies a force on any vertical face of the outer box, it force will be evenly applied over 18 bolts.That gives the box's faces a strength of 24,000 lbs. each at minimum. In the up direction there are 2 latches and 2 hinges, with 2 bolts connecting each latch and 5 bolts connecting each hinge. The reaction forces of the bolts will counter the induced force on the lid. The weakest component of the lid is the hinges, and each are rated at 5,000 lbs. each in shear. The loads and factors of safety are shown in the following table.Table 8-2: Induced G-Loads and Factors of SafetyG-Load Direction Induced Force Structural Strength of Box Factor of Safety9g's Forward 720 lbs. 24,000 lbs. 33.33g's Aft 240 lbs. 24,000 lbs. 1006g's Down 480 lbs. 16,488 lbs. 34.42g's Lateral Left (Back of box)160 lbs. 24,000 lbs. 1502g's Lateral Right (Front of box)160 lbs. 24,000 lbs. 1502g's Up 160 lbs. 10,000 lbs. 62.59. Electrical Analysis9.1 Electrical SchematicFigure 9-1: Electrical SchematicThe system shows the block arrangement for the relays, sensors, and computer used in the system. The relays, in addition to being optically activated, can be activated by pushing a button parallel with the optical sensors.The power supply provides +5VDC, +12VDC, and +24VDC power to the relays and the system. The computer is a Gateway Solo laptop, 1.0 GHz, Pentium 4 processor, 128 MB RAM, running an MS-DOS based program called ZGel that controls the system.9.2 Load Analysis

The electronic sensors on the microstopcocks, LEDs, and the photocells on the zypette do not use any substantial current and are powered off of the computer's parallel port. The relays power the laser diodes, motors, and actuator.Table 9-1: Load TableWire Gauge Current DrawnMax Current Voltage Devices Current1 Power Strip Cord14 9.4 Amps Max 20 Amps 115 VAC @ 60HzLaser control module and laser x 3250 mA x 3 =750 mAMotor control module and motor x 31.2 A x 3 = 3.6AActuator control module x 2250 mA x 2 = 500 mAComputer 2.5 A Actuator 2.0 ATotal 9.4 A9.3 Emergency Shutdown ProceduresEmergency shutdown can be performed by pressing the power switch on the main power strip. This switch will deactivate all electronics in the system, and cut power to the computer. The computer will then go into battery mode, so our data will be saved. The electronics can be repaired if necessary during a portion of 1-g or zero-g, and can be reinitiated.10. Pressure Vessel CertificationThe system uses glassware that utilizes slight pressure differentials to draw liquids into the apparatus and dispense them into the molds. All reagent bags and molds are volume expandable and collapsible, so no pressure can build up during nominal operationThe system is comprised of standard steel needles, Luer locks, a modified borosilicate syringe, and a modified set of microstopcocks. The system has been classified as Category E by JSC Personnel.10.1 SchematicConsult the Equipment Description for more detailed description of the glassware apparatus.The apparatus is comprised of a borosilicate syringe, modified with a standard ground-glass connection for a tip and a pipette-fit head. The piston in the syringe has been cut short and is fitted with a stainless steel rod secured by a threaded set screw that screws into the piston. The piston is pulled up and down by an actuator to which the steel rod is screwed.The modified zero-gravity syringe-pipette, or zypette, is fit into a four-way micro-t connection by a standard ground glass joint and sealed with silicone grease. The zypette is clipped to the joint with a Keck clip. The four-way joint, or micro-t, has three Luer lock connections for attaching syringe needles to. The micro-t has three microstopcocks to control where the liquid goes.One Luer lock is connected to a liquid-filled Mylar bag for pulling catalyst. A second Luer lock is connected to an empty Mylar bag for dumping waste.

To attach molds to the apparatus, the molds, equipped with Luer needles (connector side is exposed and cannot be removed), can be snapped onto the third lock. Molds are volume expandable by Nylon syringes.10.2 MAWP TableComponent MAWP are provided by their manufacturers, with the exception of the Mylar bags which were tested with a nitrogen tank to determine burst pressure along the edges, and divided by 2.Component MAWPZypette, borosilicate glass 200 psiMicro-T, borosilicate glass 200 psiSyringe needles 2,000 psiMylar bags 50 psiNylon syringes 100 psiMAWP for entire system: 125 psi–calculated by dividing the 25 lbs. of force the actuator can exert by the surface area of the zypette piston.This is only reached when all stopcocks are closed and actuator is pushing down. This case has been prevented by safety controls, and would not affect the Mylar bags or Nylon syringes because they are expandable. The Mylar bags have a volume of 500 mL, 100 times greater than the volume of the zypette and more than 95 greater than the entire system. Any high pressure in the system would be resolved by volume expansion into the Mylar bags, as long as it did not occur more than 20 times. This is not the normal function of the system, and will not occur. The syringe pistons would pop out if 125 psi was attained, which cannot occur when the microstopcock to the syringe is open.11. Laser CertificationThree shielded laser diodes will be used to monitor the level of the piston in the zypette during the experiment.a) Lasers are Class II, red laser diodes (similar to those used in laser pointers), 6 mm dot @ 3 meters, <1 mW optical power, 60 mA maximum current, made by National Semiconductor for the Tandy Corporation.b) Lasers are used to shine light through the zypette (across the diameter of the zypette, not across the length of it) onto photocells to electronically monitor the position of the piston.c) Lasers will be active during the entire flight.d) Lasers are shielded in opaque plastic casings and can be deactivated by a switch in the box or by the master kill switch on the power strip outside of the box.12. Parabola Details and Crew AssistanceThe experiment will try to produce 18 gels over the 30 parabolas of zero-gravity during each flight.The first two parabolas will be used to get accustomed to the zero-gravity environment and to ensure all equipment is operating within normal parameters. The last 10 parabolas will be used in case of a malfunction or to retry forming gels that did not form, and to do outreach for our video and the National Geographic Channel. No crew assistance is requested.13. Free Float RequirementsThe experiment has no free float requirements.14. Institutional Review Board

The experiment has no IRB requirements.15. Hazard Analysis ReportThe experiment uses a number of hazardous chemicals and one toxic chemical that need to be specially contained. The equipment used to form aerogels in microgravity has been designed to minimize hazards involving the release or leakage of these chemicals. The supercritical drying process mentioned in the Experiment Background is not being done in microgravity. The supercritical drying process is being done after the flight outside of NASA's facilities.DETAILED HAZARD DESCRIPTIONSHazard Number 1: Flammable/combustible material, fluid (liquid, vapor, or gas).Description: Base solution for silica alcogels is composed of flammable liquids (ethanol and tetramethoxysilane/tetraethoxysilane); danger with eye/skin contact, inhalation, ingestion.Causes: Liquid escapes from syringe or cell (mold), ignites from spark or fire.Controls: All liquids are triple-contained. Even if liquid escapes from a cell or the connected syringe, it will be contained by the inner and outer case. No sparking electrical equipment is being used (all wires are thoroughly insulated), and all apparati are bolted firmly inside to the case. All cells are firmly stored in their respective dense foam containers. No ignition sources will be used in the experiment.Hazard Number 2: Toxic/noxious/corrosive/hot/cold material, fluid (liquid, vapor, or gas).Description: Tetramethoxysilane is toxic, ammonium hydroxide is corrosive. Noncontained liquids pose health hazards/danger to equipment, danger of contact with eyes/skin, inhalation.Ingestion.Causes: Liquid escapes from Mylar bags, case breaks/leaks, glass components crack and leak.Controls: All liquids are triple contained. Even if liquid escapes from a Mylar bag or any glass components, it will be contained by the inner and outer case. However, toxic chemicals will be used in extremely small/dilute quantities. Applicable temperature range for polycarbonate thermal applications: 0 – 200oF. Polycarbonate is resistant to all chemical components used in this project.Hazard Number 3: Flammable/combustible material, fluid ignition source (i.e,short circuit;under-sized wiring/fuse/circuit breaker).Description: Base solution for silica alcogels is composed of flammable liquids (ethanol and tetramethoxysilane/tetraethoxysilane), spark ignites noncontained liquid; burns, suffocation.Causes: Structural failure of experimental case, linear actuator may spark from overload in power supply. Wiring insulation degradation.Controls: Liquids are triple-contained. Power supply is limited to maximum of 12 Volts.Power supply significant distance from experimental case and chemical solutions. Wiring insulation is resistant to chemicals used in this experiment.Hazard Number 4: Glass apparatus comes unclamped from case / steel ring stand.Description: Glassware becomes unclamped from case, free floats.

Causes: Excessive structural loads, team members hands knock these clamps loose.Controls: Clamps will be tightened and thoroughly inspected prior to each flight. Each glass component is relatively short and thick, unlikely to crack. Pipetting glass components are not directly in user's range of motion.Hazard Number 5: Mylar bags become unattached to the micro-T, or a Mylar bag is cut.Description: Steel connection to the Mylar bag becomes loose.Threat of exposure to toxic liquids. Thin steel rod may puncture other materials, including gloves.Causes:User's hands accidentally disrupts steel-Mylar bag connection. Micro-T breaks/shatters, resulting in sharp glass particles that may puncture bag.Controls: Steel-Mylar bag connection is tightened by rubber o-ring. Micro-T is manufactured to minimize possibility of breaking, designed as short, thick glass. All other components inside of inner case have blunt edges. User must be aware of this potential hazard.Hazard Number 6: Syringe pistons on cells come out of syringe chassis.Description: The piston of the syringe is somehow removed and hazardous liquids can leak out. Danger of contact with eyes/skin, inhalation, ingestion.Causes: The syringe is pushed too far, comes out of the shell, and allows hazardous fluids to leak out.Controls: Syringe piston is cut-off so that external forces may not introduce torque. Maximum volumedisplacement from the cell will is 5 ml (actuator is fully extended at displacing 5ml of liquid). Syringe is built to allow 7 ml of liquid. Cover slip is bolted at end of syringe so that piston cannot be removed.Hazard Number 7: Syringe connection to the aerogel cell comes loose.Description: Hazardous liquids leak out of apparatus. Presents danger of eye/skin contact, inhalation, ingestion.Causes: Connection badly assembled, damaged.Controls: Cells are securely fastened to syringes with Luer locks. Liquids are triple-contained and cannot leak out into the air.Hazard Number 8: Steel tubing fractures, liquid leaks out of assembly.Description: Hazardous liquids leak out of apparatus. Presents danger of eye/skin contact, inhalation, ingestion.Causes: Damaged steel tubing.Controls: Steel tubing is built to withstand 70000 psi.Highly unlikely for the steel tubing to break. Hazard Number 9: Aerogel cell is not adequately attached to micro-T.Description: Glass tubing/ Luer lock is inadequately attached to aerogel mold, assembly leaks. Presents danger of liquids leaking out of apparatus, danger of contact with eyes/skin, inhalation, ingestion.Causes: Glass tubing not properly secured onto aerogel mold, Luer lock is not set.

Controls: User will have to be sure to firmly connect the cell to the micro-T. Luer lock has to be securely fastened. All chemicals are contained within double-walled polycarbonate box.Hazard Number 10: Outer case cracks/becomes unbolted.Description: Outer case bolt connections become loose, structural failure.Cause: Extremely high-velocity impact to container chests, poor construction.Controls: Structural analysis predicts all fastened components to the outer case to withstand all g-load specifications. Inner case is initial barrier to experimental apparatus, inner case would have to fail first.Hazard Number 11: Inner case cracks/becomes unbolted.Description: Inner case bolt connections become loose, structural failure.Cause: Extremely high-velocity impact to container chests, poor construction.Controls: Structural analysis predicts all fastened components to the outer case to withstand all g-load specifications. Outer case is designed to provide back-up to the inner case.Hazard Number 12: Inner or outer case lid comes open.Description: Aluminum/polycarbonate lid becomes loose and opens.Cause: Lid insufficiently locked shut or hinges come unloose, rubber o-rings do not adhere.Controls: Hinges and clips are securely fastened to withstand all g-load specifications. Lids will be securely fastened and tested directly prior to flight. If lids need to be opened during flight, user needs to be absolutely sure to refasten clips. Inner and outer cases complement each other so if one opens, the other should remain closed.Hazard Number 13: Computer, sensor interface, accelerometer, or power strip shorts out/sparks/breaks.Description: Malfunction in power supply or computer causes a spark, power to computer is lost. Poses risk of electric fire.Cause: Power surge from aircraft power supply, damage to one of the components causes it to malfunction.Controls: A surge protector, equipped with a master kill switch, is used in the event of electrical problems. If the computer or sensor interface shorted out, it would merely shut off and would pose no real health hazard.No software-controlled devices or procedures are utilized during the experiment and so power failure does not pose a health risk to the researchers or the crew. Sparks pose a risk of fire since flammable liquids are used in the formation of the silica alcogels, but those liquids are triple-contained in sealed plastic containers and are placed a sufficient distance from the power supply that risk of ignition of the liquids is extremely improbable. In addition, the power strip is UL listed and is unlikely to spark or malfunction.Hazard Number 14:Glass micro-T breaks.

Description: Glass micro-T fractures in one or more places, resulting in sharp pieces of glass inside the inner case.May cut user's hands.Cause: Excessive structural load, team member mishandles equipment, clamping mechanism comes unloose.Controls: Micro-T is designed to withstand all g-loads specified in structural analysis. User must be aware to avoid any actions that may compromise integrity of micro-T. Prior to flight, all clamping mechanisms will be thoroughly tested and locked to avoid structural failure. PODs will be securely fastened in their holding compartments and the POD in use will be secured to either the Luer lock and the micro-T or the passive damping system (PDS). Elastic binding to the PDS will ensure that the PDS will not contact the micro-T (indicated in structural analysis). Two sets of gloves from the inner and outer case protect user's hands.Hazard Number 15: Linear actuator failure.Description: Actuator comes loose inside inner case, breakage of other components, fire.Cause: Clamping mechanism on actuator fails, free-floating actuator fractures glass or steel components inside inner case, short-circuit or exposed wires may cause sparks or even fire inside inner case.Controls: Clamping mechanism is thoroughly inspected prior to each flight. Actuator is calculated to withstand all g-load specifications. All wires are insulated to avoid possible sparks. Polycarbonate is electrically (17 ohm-cm) and fire (flammability = V-2) resistant on inner and outer case to avoid electrical complications from the actuator.Double containment of linear actuator.Hazard Number 16: Cell casing comes apart.Description: Toxic chemicals are released inside the inner case.Cause: Clamps loosen,excessive pressure build-up. Cell edges leak noxious liquid components.Controls: Clamps are securely fastened and tightened prior to each flight. Edges of each cell will be attached to the clamping mechanism via a rubber gasket material. Attachments are designed to withstand all g-load specifications. Syringe attached to cell dissipates majority of any pressure build-up from catalyst injection.Hazard Number 17: Catalyst does not flow well through the micro-T.Description: Leakage of toxic chemicals into inner case.Cause: Build-up of excessive fluids may increase micro-T pressure and cause leakage. Poor flow, tubing too small. Undesired mixing of catalyst and base if base leaks from cell into micro-T.Controls: Second steel tube running from micro-T to another Mylar bag can allow excess fluids through and release pressure build-up. Positive pressure from linear actuator ensures that there will be very minimal leakage of base from cell into the micro-T. Any base that does enter the micro-T can be flushed into the Mylar bag. Also, manipulation of micro-stopcocks will not allow base to come into micro-T. Micro-T has been designed and tested to allow catalyst to flow smoothly without any turbulence or clotting.Hazard Number 18: Laptop failure.Description: Loss of automated experimental capabilities.

Cause: Low battery, computer virus, straps loosen and laptop begins to free float and connection to apparatus is lost.Controls: We will bring a back-up battery on each flight and use anti-virus software. Straps will be securely fastened and tested prior to each flight. Connection to apparatus has several points of attachment, ensuring that connection will remain under all g-load specifications. Experiment may still operate under a manual mode.Hazard Number 19: Optoelectronics failure.Description: Loss of automated experimental capabilities, excessive heating of toxic/flammable chemicals.Cause: Lasers may become loose, inoperable Controls: Lasers are certified for use and emit low energy. Lasers are securely fastened to the zypettte and connections are calculated to withstand all g-load specifications. Low energy dissipated from both lasers makes the likelihood of igniting a fire extremely unlikely.Hazard Number 20: Glove openings from case to inside of apparatus ruptures.Description: Exposure of user to potentially dangerous chemicals, broken glass, sharp thin steel rods.Cause: Glove material tears with excessive loading by user. Laceration of material by sharp pieces from inside the inner case or outside of the outer case. Any excessive puncturing force may rupture glove material.Controls: Two sets of gloves are used; one set attached to the outer case, one set attached to the inner case. No sharp objects will be allowed near the experiment. Gloves are made of durable, chemically inert rubber. Attachments of gloves to their respective cases can withstand all g-load specifications.Hazard Number 21: Steel-clamping rod (ring stand) dislodges from inner case.Description: Equipment damage, broken glass and exposed sharp steel rods.Cause: Bolts loosen, become unattached so that apparatus may free-float inside of the inner case.Controls: Connections of steel clamping rod to the inner case are designed to withstand all g-load specifications. Inner and outer casing ensures that no parts of apparatus will become exposed to cabin of the KC-135A. Bolted and epoxied in place with 4 heavy bolts and ceramic-metal epoxy.Hazard Number 22: Connection between inner and outer casing fails.Description: Inner case becomes a free-floating object, increasing likelihood of toxic chemical exposure to cabin of KC-135A.Cause: Bolts connecting the inner case to the outer case fail.Controls: Bolt connections are designed to withstand all g-load specifications. Outer case is structurally sound to withstand all possible external forces applied by the inner case.Hazard Number 23: Outer case becomes loose.Description: Outer case becomes a free-floating object in the KC-135A cabin. Possible physical injury to team members orany personnel in the vicinity of the experiment.

Cause: Failure of fastening devices and/or tether straps.Controls: A thorough pre-flight test analysis will be conducted to ensure casing is firmly fastened to the inside of the airplane. Structural analysis shows that fastening mechanism is designed to withstand all g-loadspecifications.Hazard Number 24:Stopcock jams, unable to move.Description: Inability to move stopcock may result in poor aerogel yields, back flow of base into the micro-T, excessive pressure build-up, leakage of toxic chemicals into inner case.Cause: Back flow of base into micro-T, solidifying connection of micro-T to the stopcock. Dry glass-glass connection,no lubricant.Excessively cold temperatures.Controls: All stopcocks will easily be accessible to team members for manual adjustments. Glass-glass connections will be lubricated prior to use to minimize chances of jamming. Temperatures will not drop below 32oF. Back flow of base into micro-T will be minimized by careful user experimental technique; excessive amounts may be flushed out of micro-T by the linear actuator and the Mylar waste bag.Hazard Number 25: Aerogel foam shelving units become detached, cracked Description: Free-floating PODs (protective outer devices) in the inner case, leakage of toxic chemicals.Cause: Velcro straps holding the PODs in place may lose their adhesiveness, bolts attaching foam to inner case may become loose, foam degrades or is pulled apart from bolts/inner case.Controls: Velcro straps are new and thoroughly tested to withstand all g-load specifications. Pre-flight analysis will ensure POD shelving units are ready for use. Bolt/epoxy attachment of foam to the inner case is designed to withstand all g-load specifications. Foam is relatively dense, highly unlikely to degrade or come apart from all connections. Inner and outer case ensures no toxic chemical exposure to team members or any other personnel in the KC-135A.Hazard Number 26: Explosion in micro-T or zypette.Description: Toxic chemicals released into the environment, loss of aerogel molds.Cause: Temperatures exceeding boiling points of liquids used, gases causing increased pressure in apparatus. Excessive liquid pressure build-up.Controls: Temperatures will be well below the boiling points of our chemical liquids. The syringe in the cell or the 2nd Mylar bag may dissipate any liquid pressure build-up. Extremely unlikely that an explosion could occur, since chemicals being used are in dilute solutions, and no off-gassing takes place.Hazard Number 27: Laser damages retina of team members.Description: Temporary or permanent eye damage (i.e., retinal damage) to team members.Cause: Clamping mechanism failure, excessive structural loading, and high-powered laser.Controls: Power and intensity of lasers is much less than dangerous levels. Laser clamping mechanisms can withstand all g-load specifications. Lasers are certified for safety. Lasers are contained in opaque clamps and are not visible unless

clamps are taken apart. If a laser did come loose, it would detach from the electrical connection before it would come out of the casing.Hazard Number 28: Velcro on Mylar bags becomes loose.Description: Free-floating Mylar bags, collision with object in box, may release toxic chemicals to the inside of the inner case.Cause: Poor Velcro, worn out, dirty, bumped on accident.Controls: New Velcro will be used, replaced if necessary. Back-up Velcro will be carried onboard in case of failure. Plastic containers containing the Mylar bags are securely fastened to the inner case and can withstand all g-load specifications. Bags are secured by 5 Velcro straps, unlikely to all fail. Bags still held in place by needles penetrating them.Hazard Number 29: Epoxy attachments become loose.Description: Potential for toxic chemicals to become exposed to inside of KC-135A cabin.Cause: Epoxy attachments between polycarbonate and aluminum L-beams or plates become loose or degrade.Controls: All epoxy adhesive attachment sites use a thorough amount of epoxy. Connections are strong enough to withstand all g-load specifications. No connection is solely dependent on an epoxy bond, but a combination of bolts, rubber seals and gaskets, and friction fits.Hazard Number 32: Linear actuator connection to the zypette breaks, comes off.Description: Potential break on zypette, loss of automated dispensing.Cause: Linear actuator spins, possibly causing excessive torque on the steel rod connecting to the piston inside the zypette. Bolts on the actuator come loose, clamping mechanism holding the bolts come loose.Controls: Bolts and clamping mechanism are securely fastened and tested prior to flight. Clamping mechanism is designed to withstand all g-load specifications and torque introduced by the linear actuator.Epoxy connection to the steel rod connected to the actuator is very strong, held in place by threaded connection to the piston inside the zypette.Hazard Number 33: Luer locking mechanisms fail.Description: Toxic chemicals released into inner case.Cause: Luer locking mechanisms fail, poorly fastened, user mishandles apparatus.Controls: Luer locking mechanisms connecting the zypette and Mylar bags to the micro-T will be securely fastened and tested prior to flight. Luer locking mechanisms between the micro-T and the individual cells have to be carefully handled by a team member. Team member must be aware of always fastening the Luer locking mechanism before initiating catalyst injection into the cell. Apparatus is triple-contained so that even if liquid were released into the box, it would be contained.Hazard Number 34: Electrical or computer failure causes uncontrolled mechanical stressDescription: Fire, breakages.

Cause: Unknown, possibly loose electrical connection, static discharge shorts out circuitry, Microsoft product present on computer.Controls: Master Kill Switch located on the outside of the outer case. Cuts power to all systems, including computer and electronics.Hazard Number 35: Wire connection from laptop to apparatus becomes severed or exposed to environment.Description: Exposed electrical wires with active voltage source, toxic chemical exposure to cabin of aircraft.Cause: Epoxy covering holes for wire feeds comes loose, possibly from excessive structural loads, disconnection of inner and outer case.Controls: Power to all electronic equipment will be shut down if there are exposed wires until the problem is remedied. Inner and outer cases are firmly bolted to each other, ensuring wire connections will be maintained under all g-load specifications.Hazard Number 38: Opening of lid during flight may expose toxic chemicals to cabin environment.Description: Exposure of toxic chemicals to the cabin of the aircraft.Cause: Intentional opening of inner and outer case lids to fix problems that can't be resolved with only gloves.Controls: Permission will be asked before opening, lids will not be opened during periods of reduced gravity, only during periods of 1-2 g's.Hazard Number 39: Handle on inner lid comes unloose.Description: Free-floating handle in cabin poses risk of injury.Cause: Poor lid handle attachment, excessive structural load applied by g-forces or team member or other persons operating the equipment.Controls: All bolts connecting handles to the inner and outer case lids can withstand all g-load specifications and are reinforced by four other bolts.Hazard Number 40: Protective outer device (POD) for each cell may structurally fail.Description: Release of breakable glass components / toxic chemicals into the inside of the inner box.Cause: Aluminum or Velcro or foam failure of the POD design from excessive structural loads, user mishandling, abuse, external loading.Controls: Four sides of a POD consist of aluminum that can resist considerable amounts of structural loading. All Velcro components are new, with maximum adhesive qualities. Foam maintains soft intermediate between fragile glass components of the cell and any external pieces. User will be careful when handling individual PODs. Only one POD will be handled at a time.Hazard Number 41: Clamping mechanism to the zypette fails, comes loose.Description: Fragile glass components may free-float in inner case, potential for shattering, and danger for user.Cause: Loosening of clamping mechanism from external forces, possible by a team member. Excessive loading. Excessive torque applied by the linear actuator. Clamping mechanism itself may crush the zypette.

Controls: Zypette is securely fastened to two ring stands in two places. Clamping mechanism is designed to withstand all g-load specifications. Clamping mechanism may need to use cloth or double-sided sticky adhesive between the clamp and the zypette to reduce the possibility of inwards crushing.Hazard Number 42: Clamping mechanism to the micro-T may fail.Description: Fragile glass components may free-float in inner case, potential for shattering, and danger for user.Cause: Loosening of clamping mechanism from external forces, possible by a team member.Excessive loading. Excessive torque applied by the linear actuator. Clamping mechanism itself may crush the micro-T.Controls: Clamps are strong enough to dissipate possible torque created by the linear actuator, but not strong enough to crush the micro-T. All clamping of glassware will be carefully constructed and tested prior to each flight.Hazard Number 43: Laceration of team member with sharp object.Description: Team member needs medical attention, bleeding, etc.Cause: Excessive structural loading, broken apparatus inside inner case, cuts through gloves and team member's skin.Controls: All materials inside inner case are designed to withstand all g-load specifications without breaking, two layers of gloves are used, first-aid medical kit is present onboard for any necessary medical attention.Hazard Number 44: Edges of outer case injure team members.Description: Bruising, external/internal bleeding, broken bones.Cause: Person cuts or falls onto the outer case. Edges may cut or bruise person who is not careful and is near the outer case when the KC-135A enters 2-g from reduced gravity.Controls: Outer edges of outer case have foam duct-taped to each edge, eliminating exposure to any sharp corners. First-aid kit is readily available for anyone who needs medical attention.16. Tool RequirementsAll tools used will be for ground maintenance and will be contained in a composite tool kit with Styrofoam cutouts for ease of inventory evaluation. All tools will be marked with the initials UW for identification. This should provide a quick means of discovering missing tools and minimize the risk of tools causing foreign object damage (FOD) to aircraft. In addition, all aluminum foil, paper, and plastic sheet products will be closely tracked to prevent any FOD to aircraft. The following tools will be brought.1. Standard flathead and Phillips screwdriver2. (1) roll duct tape3. (1) roll of resin core solder4. Soldering iron5. Needle nose pliers6. (2) packs of epoxy7. (2) tubes of gasket compound8. Crescent wrench

9. Electric screwdriver/drill kit10. Spare bolts, washers, and nuts for equipment

The following materials and equipment are part of the experiment apparatus.1. 1/4" Drilled polycarbonate sheets2. (2) Micro-T connectors (manufactured by UW Chemistry Department Glass Shop)3. (2) 5mL zypettes (zero-gravity syringe-pipettes, manufactured UW Chemistry Department Glass Shop)4. (2) 25-lb. 24VDC Actuators5. (4) Steel Luer-lock needles (1/16" diameter)6. (36) Alcogel syringe-molds (including glass plates, rubber O-rings, and syringes)7. (20) 1/4" Drilled aluminum L-beams8. (2) Pairs of drybox gloves, butyl and neoprene9. (4) 6.0V 40mW Laser diodes10. (4) Hinges for inner and outer casing lids11. (2) Drilled ring stands12. Laptop computer13. Electronic interface for computer and apparatus14. 24VDC power supply15. 17. Photo RequirementsWe will be using a journalist to take photographs and videotape of the experiment. We will not require the usage of S-band downlink. Our journalist will use a MiniDV camcorder to record video for the National Geographic Channel. We will be using a Panasonic MiniDV camcorder to record our experiment. We will require camera-mounting poles for the camcorder. In addition to bringing a MiniDV camcorder to record our experiment, we will also bring our own 35mm camera.18. Aircraft LoadingWe will be using a forklift to carry the inner and outer casing and all equipment up to the KC. After the forklift reaches the level of the entrance to the aircraft, two people will be needed to carry the inner and outer casings and equipment aboard the aircraft.There will be 2 handles on either side of the two boxes so that the 4 people can lift the boxes and equipment aboard the KC. The inner casing, outer casing, and equipment in the boxes weigh less than 200 pounds. Shoring for the floor is requested for the apparatus The boxes will contain the equipment that will be brought aboard the KC for the experiment.Note: See Procedures for detailed information about the loading process.Table 18-1: Weight TableItem Weight of ItemsLaser Diodes and Electronics 0.5 lbs.Glassware (not including molds) 0.5 lbs.Actuator 1 lb. Camcorders (2) 6 lbs.Ring Stands 4 lbs.Spare Parts 1 lb.Laptop Computer 5 lbs.Inner Encasement 80 lbs.

Outer Encasement 80 lbs.Molds (filled) 4 lbs.Tool Kit 5 lbs.Total Weight: 187 lbs.Note: See Equipment Description section for pictures of the items described in the weight table above.19. Ground Support RequirementsPower Requirements:Standard 120 VAC 60 Hz power is required for testing pipetting apparatus, computer and sensor interfaces.Hazardous Substance Requirements:Storage for 15.1 M ammonium hydroxide, denatured ethanol, tetramethoxysilane, and tetraethoxysilane is needed. Space to mix the chemicals is required, but no ventilation is needed. Beakers, stirring rods, and bottles for storing the solutions in will be brought by the researchers.Access to Building 993 During Non-business Hours:Access to Building 993 is not requested during non-business hours.Pressurized Gas Requirements:No pressurized gas requirements. Our project will not require the use of any pressurized gas.General Tool Requests:No general tool requests.20. Hazardous MaterialsThe experiment uses two liquids that both contain hazardous materials. The liquids are both triple-contained within the equipment, and all materials used to build the equipment are chemical resistant.Catalyst SolutionContains: water, ethanol, 15.1 M ammonium hydroxide Hazard: toxic, corrosive, releases pungent odor Containment: Stored in Mylar bags, handled within double-walled polycarbonate box, used in dilute solution, only used in liquid-tight systemBase SolutionContains: water, ethanol, tetramethoxysilane or tetraethoxysilane, 15.1 M ammonium hydroxideHazard: toxic, lachrymator, targets organs, lungs, blood, kidneysContainment: Stored in sealed glass molds in double-walled polycarbonate box, becomes safe once gel is formed21. Material Safety Data SheetsMaterial Safety Data Sheet for 15.1 M Aqueous Ammonium Hydroxide SolutionValid 05/2001 - 07/2001Riedel-de Haen3050 Spruce St. St. Louis, MO 63178 USA Tel: 314-289-6000M A T E R I A L S A F E T Y D A T A S H E E TSECTION 1. - - - - - - - - - CHEMICAL IDENTIFICATION- - - - - - - - - -CATALOG #: 05002NAME: AMMONIA SOLUTION MAX. 33% NH3, EXTRA PURE

SECTION 2. - - - - - COMPOSITION/INFORMATION ON INGREDIENTS - - - - - -CAS #: 1336-21-6EC NO: 215-647-6SYNONYMSAMMONIA AQUEOUS * AMMONIA WATER 29% * AQUA AMMONIA *SECTION 3. - - - - - - - - - - HAZARDS IDENTIFICATION - - - - - - - - -LABEL PRECAUTIONARY STATEMENTS CORROSIVE DANGEROUS FOR THE ENVIRONMENT TOXIC IF SWALLOWED. LACHRYMATOR.IN CASE OF ACCIDENT OR IF YOU FEEL UNWELL, SEEK MEDICAL ADVICEIMMEDIATELY (SHOW THE LABEL WHERE POSSIBLE).IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.WEAR SUITABLE PROTECTIVE CLOTHING, GLOVES AND EYE/FACEPROTECTION.AVOID RELEASE TO THE ENVIRONMENT. REFER TO SPECIAL INSTRUCTIONS/SAFETY DATA SHEETS.SECTION 4. - - - - - - - - - - FIRST-AID MEASURES- - - - - - - - - - -IF SWALLOWED, WASH OUT MOUTH WITH WATER PROVIDED PERSON IS CONSCIOUS.CALL A PHYSICIAN.DO NOT INDUCE VOMITING.IF INHALED, REMOVE TO FRESH AIR. IF NOT BREATHING GIVE ARTIFICIALRESPIRATION. IF BREATHING IS DIFFICULT, GIVE OXYGEN.IN CASE OF SKIN CONTACT, FLUSH WITH COPIOUS AMOUNTS OF WATERFOR AT LEAST 15 MINUTES. REMOVE CONTAMINATED CLOTHING ANDSHOES. CALL A PHYSICIAN.IN CASE OF CONTACT WITH EYES, FLUSH WITH COPIOUS AMOUNTS OF WATER FOR AT LEAST 15 MINUTES. ASSURE ADEQUATE FLUSHING BY SEPARATINGTHE EYELIDS WITH FINGERS. CALL A PHYSICIAN.SECTION 5. - - - - - - - - - FIRE FIGHTING MEASURES - - - - - - - - - -EXTINGUISHING MEDIA NONCOMBUSTIBLE. USE EXTINGUISHING MEDIA APPROPRIATE TO SURROUNDING FIRE CONDITIONS.SPECIAL FIREFIGHTING PROCEDURES WEAR SELF-CONTAINED BREATHING APPARATUS AND PROTECTIVE CLOTHING TOPREVENT CONTACT WITH SKIN AND EYES.UNUSUAL FIRE AND EXPLOSIONS HAZARDS EMITS TOXIC FUMES UNDER FIRE CONDITIONS.SECTION 6. - - - - - - - - ACCIDENTAL RELEASE MEASURES- - - - - - - - -WEAR SELF-CONTAINED BREATHING APPARATUS, RUBBER BOOTS AND HEAVY RUBBER GLOVES.COVER WITH DRY LIME OR SODA ASH, PICK UP, KEEP IN A CLOSED CONTAINER AND HOLD FOR WASTE DISPOSAL.VENTILATE AREA AND WASH SPILL SITE AFTER MATERIAL PICKUP IS COMPLETE.EVACUATE AREA.

SECTION 7. - - - - - - - - - - HANDLING AND STORAGE- - - - - - - - - - -REFER TO SECTION 8.SECTION 8. - - - - - - EXPOSURE CONTROLS/PERSONAL PROTECTION- - - - - SAFETY SHOWER AND EYE BATH.USE ONLY IN A CHEMICAL FUME HOOD.WASH CONTAMINATED CLOTHING BEFORE REUSE.DISCARD CONTAMINATED SHOES.WASH THOROUGHLY AFTER HANDLING.DO NOT BREATHE VAPOR.DO NOT GET IN EYES, ON SKIN, ON CLOTHING.AVOID PROLONGED OR REPEATED EXPOSURE.NIOSH/MSHA-APPROVED RESPIRATOR.COMPATIBLE CHEMICAL-RESISTANT GLOVES.CHEMICAL SAFETY GOGGLES.FACESHIELD (8-INCH MINIMUM).KEEP TIGHTLY CLOSED.STORE IN A COOL DRY PLACE.REFRIGERATE BEFORE OPENING.SECTION 9. - - - - - - - PHYSICAL AND CHEMICAL PROPERTIES - - - - - - -PHYSICAL PROPERTIESMELTING POINT: -77 CEXPLOSION LIMITS IN AIR:UPPER 27 %LOWER 16 %VAPOR PRESSURE: 115 MMHGSPECIFIC GRAVITY: 0.9 GVAPOR DENSITY: 1.2 G/LSECTION 10. - - - - - - - - -STABILITY AND REACTIVITY - - - - - - - - -STABILITYSTABLE.INCOMPATIBILITIESCOPPER, COPPER ALLOYSGALVANIZED IRONZINCHAZARDOUS COMBUSTION OR DECOMPOSITION PRODUCTSAMMONIAHAZARDOUS POLYMERIZATIONWILL NOT OCCUR.SECTION 11. - - - - - - - - - TOXICOLOGICAL INFORMATION - - - - - - - -ACUTE EFFECTSMATERIAL IS EXTREMELY DESTRUCTIVE TO TISSUE OF THE MUCOUS MEMBRANESAND UPPER RESPIRATORY TRACT, EYES AND SKIN.INHALATION MAY RESULT IN SPASM, INFLAMMATION AND EDEMA OF THELARYNX AND BRONCHI, CHEMICAL PNEUMONITIS AND PULMONARY EDEMA.

SYMPTOMS OF EXPOSURE MAY INCLUDE BURNING SENSATION, COUGHING,WHEEZING, LARYNGITIS, SHORTNESS OF BREATH, HEADACHE, NAUSEA AND VOMITING.CAUSES BURNS.MAY BE HARMFUL IF ABSORBED THROUGH THE SKIN.LACHRYMATOR.MAY BE HARMFUL IF INHALED.MATERIAL IS EXTREMELY DESTRUCTIVE TO THE TISSUE OF THE MUCOUS MEMBRANESAND UPPER RESPIRATORY TRACT.HARMFUL IF SWALLOWED.RTECS #: BQ9625000AMMONIUM HYDROXIDEIRRITATION DATAEYE-RBT 250 UG SEV AJOPAA 29,1363,1946EYE-RBT 44 UG SEV AROPAW 25,839,1941EYE-RBT 1 MG/30S RINSE SEV TXCYAC 23,281,1982TOXICITY DATAORL-HMN LDLO:43 MG/KG 34ZIAG -,95,1969IHL-HMN LCLO:5000 PPM 34ZIAG -,95,1969ORL-RAT LD50:350 MG/KG JIHTAB 23,259,1941IVN-MUS LD50:91 MG/KG JCINAO 37,497,1958TARGET ORGAN DATABEHAVIORAL (CONVULSIONS OR EFFECT ON SEIZURE THRESHOLD)BEHAVIORAL (COMA)LUNGS, THORAX OR RESPIRATION (FIBROSIS, FOCAL)LUNGS, THORAX OR RESPIRATION (ACUTE PULMONARY EDEMA)LUNGS, THORAX OR RESPIRATION (RESPIRATORY STIMULATION)GASTROINTESTINAL (OTHER CHANGES)LIVER (OTHER CHANGES)KIDNEY, URETER, BLADDER (OTHER CHANGES)ONLY SELECTED REGISTRY OF TOXIC EFFECTS OF CHEMICAL SUBSTANCES(RTECS) DATA IS PRESENTED HERE. SEE ACTUAL ENTRY IN RTECS FORCOMPLETE INFORMATION.SECTION 12. - - - - - - - - - ECOLOGICAL INFORMATION - - - - - - - - - -DATA NOT YET AVAILABLE.SECTION 13. - - - - - - - - - DISPOSAL CONSIDERATIONS - - - - - - - - -CONTACT A LICENSED PROFESSIONAL WASTE DISPOSAL SERVICE TO DISPOSE OF THIS MATERIAL.DISSOLVE OR MIX THE MATERIAL WITH A COMBUSTIBLE SOLVENT AND BURN IN ACHEMICAL INCINERATOR EQUIPPED WITH AN AFTERBURNER AND SCRUBBER.OBSERVE ALL FEDERAL, STATE AND LOCAL ENVIRONMENTAL REGULATIONS.

SECTION 14. - - - - - - - - - - TRANSPORT INFORMATION - - - - - - - - -CONTACT SIGMA CHEMICAL COMPANY FOR TRANSPORTATION INFORMATION.SECTION 15. - - - - - - - - - REGULATORY INFORMATION - - - - - - - - - -EUROPEAN INFORMATIONEC INDEX NO: 007-001-01-2CORROSIVE DANGEROUS FOR THE ENVIRONMENTR 34CAUSES BURNS.R 50VERY TOXIC TO AQUATIC ORGANISMS.S 26IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.S 36/37/39WEAR SUITABLE PROTECTIVE CLOTHING, GLOVES AND EYE/FACEPROTECTION.S 45IN CASE OF ACCIDENT OR IF YOU FEEL UNWELL, SEEK MEDICAL ADVICEIMMEDIATELY (SHOW THE LABEL WHERE POSSIBLE).S 61AVOID RELEASE TO THE ENVIRONMENT. REFER TO SPECIAL INSTRUCTIONS/SAFETY DATA SHEETS.REVIEWS, STANDARDS, AND REGULATIONSOEL=MAKNOHS 1974: HZD 06145; NIS 297; TNF 85664; NOS 161; TNE 735671NOES 1983: HZD 06145; NIS 326; TNF 66188; NOS 188; TNE 1022551; TFE379643EPA TSCA SECTION 8(B) CHEMICAL INVENTORYEPA TSCA SECTION 8(D) UNPUBLISHED HEALTH/SAFETY STUDIESEPA TSCA TEST SUBMISSION (TSCATS) DATA BASE, JANUARY 2001SECTION 16. - - - - - - - - - - OTHER INFORMATION- - - - - - - - - - - -THE ABOVE INFORMATION IS BELIEVED TO BE CORRECT BUT DOES NOT PURPORT TOBE ALL INCLUSIVE AND SHALL BE USED ONLY AS A GUIDE. SIGMA, ALDRICH,FLUKA SHALL NOT BE HELD LIABLE FOR ANY DAMAGE RESULTING FROM HANDLING OR FROM CONTACT WITH THE ABOVE PRODUCT. SEE REVERSE SIDE OF INVOICE OR PACKING SLIP FOR ADDITIONAL TERMS AND CONDITIONS OF SALE.COPYRIGHT 2001 SIGMA-ALDRICH CO.LICENSE GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLYMaterial Safety Data Sheet for Ethanol, Denatured with 4.8% IPAValid 05/2001 - 07/2001Fluka Chemical Corp. 1001 West St. Paul Milwaukee, WI 53233 USA

Tel: 414-273-3850M A T E R I A L S A F E T Y D A T A S H E E TSECTION 1. - - - - - - - CHEMICAL IDENTIFICATION- - - - - CATALOG #: 02853NAME: ETHANOL, DENAT. WITH 4.8% ISOPROPANOL, 'F25 IPA'SECTION 2. - - - - - COMPOSITION/INFORMATION ON INGREDIENTS - - - - - -CAS #: 64-17-5EC NO: 200-578-6HAZARDOUS INGREDIENTSCONTAINS 2-PROPANOL (ISOPROPYL ALCOHOL), CHEMICAL ABSTRACTS REGISTRY NUMBER 67-63-0.SYNONYMSABSOLUTE ETHANOL * AETHANOL (GERMAN) * AETHYLALKOHOL (GERMAN) *ALCOHOL * ALCOHOL, ANHYDROUS * ALCOHOL DEHYDRATED * ALCOOL ETHYLIQUE(FRENCH) * ALCOOL ETILICO (ITALIAN) * ALGRAIN * ALKOHOL (GERMAN) *ALKOHOLU ETYLOWEGO (POLISH) * ANHYDROL * COLOGNE SPIRIT * ETANOLO(ITALIAN) * ETHANOL (ACGIH:OSHA) * ETHYL ALCOHOL (DOT:OSHA) * ETHYLALCOHOL ANHYDROUS * ETHYL HYDRATE * ETHYL HYDROXIDE * ETYLOWY ALKOHOL(POLISH) * FERMENTATION ALCOHOL * GRAIN ALCOHOL * JAYSOL * JAYSOL S *METHYLCARBINOL * MOLASSES ALCOHOL * NCI-C03134 * POTATO ALCOHOL * SDALCOHOL 23-HYDROGEN * SPIRITS OF WINE * SPIRT * TECSOL *SECTION 3. - - - - - - - - HAZARDS IDENTIFICATION - - - - - - - LABEL PRECAUTIONARY STATEMENTSFLAMMABLE (USA)HIGHLY FLAMMABLE (EU)IRRITANTIRRITATING TO EYES, RESPIRATORY SYSTEM AND SKIN.RISK OF SERIOUS DAMAGE TO EYES.TARGET ORGAN(S):NERVESLIVERKEEP AWAY FROM SOURCES OF IGNITION - NO SMOKING.IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.WEAR SUITABLE PROTECTIVE CLOTHING.SECTION 4. - - - - - - - - - - FIRST-AID MEASURES- - - - - - - - - - -IF INHALED, REMOVE TO FRESH AIR. IF BREATHING BECOMES DIFFICULT,CALL A PHYSICIAN.IN CASE OF CONTACT WITH EYES, FLUSH WITH COPIOUS AMOUNTS OF WATER FOR AT LEAST 15 MINUTES. ASSURE ADEQUATE FLUSHING BY SEPARATING THE EYELIDS WITH FINGERS. CALL

A PHYSICIAN.IF SWALLOWED, WASH OUT MOUTH WITH WATER PROVIDED PERSON IS CONSCIOUS.CALL A PHYSICIAN IMMEDIATELY.IN CASE OF SKIN CONTACT, FLUSH WITH COPIOUS AMOUNTS OF WATERFOR AT LEAST 15 MINUTES. REMOVE CONTAMINATED CLOTHING ANDSHOES. CALL A PHYSICIAN.WASH CONTAMINATED CLOTHING BEFORE REUSE.SECTION 5. - - - - - - - - - FIRE FIGHTING MEASURES - - - - - - - - - -EXTINGUISHING MEDIA CARBON DIOXIDE, DRY CHEMICAL POWDER OR APPROPRIATE FOAM.SPECIAL FIREFIGHTING PROCEDURESWEAR SELF-CONTAINED BREATHING APPARATUS AND PROTECTIVE CLOTHING TOPREVENT CONTACT WITH SKIN AND EYES.USE WATER SPRAY TO COOL FIRE-EXPOSED CONTAINERS.FLAMMABLE LIQUID.UNUSUAL FIRE AND EXPLOSIONS HAZARDSVAPOR MAY TRAVEL CONSIDERABLE DISTANCE TO SOURCE OF IGNITION ANDFLASH BACK.SECTION 6. - - - - - - - - ACCIDENTAL RELEASE MEASURES- - - - - - - - -EVACUATE AREA.SHUT OFF ALL SOURCES OF IGNITION.WEAR SELF-CONTAINED BREATHING APPARATUS, RUBBER BOOTS AND HEAVY RUBBER GLOVES.COVER WITH DRY-LIME, SAND, OR SODA ASH. PLACE IN COVERED CONTAINERS USING NON-SPARKING TOOLS AND TRANSPORT OUTDOORS.VENTILATE AREA AND WASH SPILL SITE AFTER MATERIAL PICKUP IS COMPLETE.SECTION 7. - - - - - - - - - - HANDLING AND STORAGE- - - - - - - - - - -REFER TO SECTION 8.SECTION 8. - - - - - - EXPOSURE CONTROLS/PERSONAL PROTECTION- - - - - -WEAR APPROPRIATE NIOSH/MSHA-APPROVED RESPIRATOR, CHEMICAL-RESISTANT GLOVES, SAFETY GOGGLES, OTHER PROTECTIVE CLOTHING.USE ONLY IN A CHEMICAL FUME HOOD.SAFETY SHOWER AND EYE BATH.DO NOT BREATHE VAPOR.DO NOT GET IN EYES, ON SKIN, ON CLOTHING.AVOID PROLONGED OR REPEATED EXPOSURE.WASH THOROUGHLY AFTER HANDLING.KEEP TIGHTLY CLOSED.KEEP AWAY FROM HEAT, SPARKS, AND OPEN FLAME.STORE IN A COOL DRY PLACE.SECTION 9. - - - - - - - PHYSICAL AND CHEMICAL PROPERTIES - - - - - - -APPEARANCE AND ODORCLEAR, COLORLESS LIQUID

SECTION 10. - - - - - - - - -STABILITY AND REACTIVITY - - - - - - - - -STABILITYSTABLE.INCOMPATIBILITIESOXIDIZING AGENTSPEROXIDESACIDSACID CHLORIDESACID ANHYDRIDESALKALI METALSAMMONIAPROTECT FROM MOISTURE.HAZARDOUS COMBUSTION OR DECOMPOSITION PRODUCTSTOXIC FUMES OF:CARBON MONOXIDE, CARBON DIOXIDEHAZARDOUS POLYMERIZATIONWILL NOT OCCUR.SECTION 11. - - - - - - - - - TOXICOLOGICAL INFORMATION - - - - - - - -ACUTE EFFECTSMAY BE HARMFUL BY INHALATION, INGESTION, OR SKIN ABSORPTION.CAUSES SEVERE EYE IRRITATION.VAPOR OR MIST IS IRRITATING TO THE EYES, MUCOUS MEMBRANES AND UPPERRESPIRATORY TRACT.CAUSES SKIN IRRITATION.CAN CAUSE CNS DEPRESSION.EXPOSURE CAN CAUSE:NAUSEA, HEADACHE AND VOMITINGNARCOTIC EFFECTDAMAGE TO THE HEARTTARGET ORGAN(S):NERVESLIVERKIDNEYSCARDIOVASCULAR SYSTEMG.I. SYSTEMRTECS #: KQ6300000ETHYL ALCOHOLIRRITATION DATASKN-RBT 400 MG OPEN MLD UCDS** 7/22/1970SKN-RBT 20 MG/24H MOD 85JCAE -,189,1986EYE-RBT 500 MG SEV AJOPAA 29,1363,1946EYE-RBT 500 MG/24H MLD 85JCAE -,189,1986EYE-RBT 100 MG/4S RINSE MOD FCTOD7 20,573,1982TOXICITY DATAORL-CHD LDLO:2 GM/KG ATXKA8 17,183,1958ORL-HMN LDLO:1400 MG/KG NPIRI* 1,44,1974

SCU-INF LDLO:19440 MG/KG AJCPAI 5,466,1935ORL-RAT LD50:7060 MG/KG TXAPA9 16,718,1970IHL-RAT LC50:20000 PPM/10H NPIRI* 1,44,1974IPR-RAT LD50:3600 UG/KG PHMGBN 2,27,1969IVN-RAT LD50:1440 MG/KG TXAPA9 18,60,1971IAT-RAT LD50:11 MG/KG TXAPA9 18,60,1971ORL-MUS LD50:3450 MG/KG GISAAA 32(3),31,1967IHL-MUS LC50:39 GM/M3/4H GTPZAB 26(8),53,1982IPR-MUS LD50:528 MG/KG STRAAA 127,245,1965SCU-MUS LD50:8285 MG/KG FAONAU 48A,99,1970IVN-MUS LD50:1973 MG/KG HBTXAC 1,128,1955ORL-RBT LD50:6300 MG/KG HBTXAC 1,130,1955IPR-RBT LD50:963 MG/KG EVHPAZ 61,321,1985IVN-RBT LD50:2374 MG/KG EVHPAZ 61,321,1985ORL-GPG LD50:5560 MG/KG JIHTAB 23,259,1941IPR-GPG LD50:3414 MG/KG EVHPAZ 61,321,1985IPR-HAM LD50:5068 MG/KG EVHPAZ 61,321,1985IPR-MAM LD50:4300 MG/KG TXAPA9 13,358,1968TARGET ORGAN DATABEHAVIORAL (SLEEP)BEHAVIORAL (CHANGE IN MOTOR ACTIVITY)BEHAVIORAL (ATAXIA)BEHAVIORAL (ANTIPSYCHOTIC)BEHAVIORAL (HEADACHE)BEHAVIORAL (CHANGE IN PSYCHOPHYSIOLOGICAL TESTS)LUNGS, THORAX OR RESPIRATION (CHRONIC PULMONARY EDEMA OR CONGESTION)LUNGS, THORAX OR RESPIRATION (DYSPNAE)LUNGS, THORAX OR RESPIRATION (OTHER CHANGES)GASTROINTESTINAL (ALTERATION IN GASTRIC SECRETION)GASTROINTESTINAL (HYPERMOTILITY, DIARRHEA)GASTROINTESTINAL (NAUSEA OR VOMITING)GASTROINTESTINAL (OTHER CHANGES)LIVER (FATTY LIVER DEGENERATION)LIVER (TUMORS)ENDOCRINE (CHANGE IN GONADOTROPINS)ENDOCRINE (OTHER CHANGES)BLOOD (OTHER CHANGES)BLOOD (LYMPHOMA INCLUDING HODGKIN'S DISEASE)PATERNAL EFFECTS (TESTES, EPIDIDYMIS, SPERM DUCT)EFFECTS ON FERTILITY (FEMALE FERTILITY INDEX)EFFECTS ON FERTILITY (MALE FERTILITY INDEX)EFFECTS ON FERTILITY (POST-IMPLANTATION MORTALITY)EFFECTS ON FERTILITY (OTHER MEASURES OF FERTILITY)EFFECTS ON EMBRYO OR FETUS (EXTRA EMBRYONIC STRUCTURES)EFFECTS ON EMBRYO OR FETUS (CYTOLOGICAL CHANGES)EFFECTS ON EMBRYO OR FETUS (FETOTOXICITY)

EFFECTS ON EMBRYO OR FETUS (FETAL DEATH)EFFECTS ON EMBRYO OR FETUS (OTHER EFFECTS TO EMBYRO OR FETUS)SPECIFIC DEVELOPMENTAL ABNORMALITIES (EYE, EAR)SPECIFIC DEVELOPMENTAL ABNORMALITIES (CRANIOFACIAL)SPECIFIC DEVELOPMENTAL ABNORMALITIES (MUSCULOSKELETAL SYSTEM)SPECIFIC DEVELOPMENTAL ABNORMALITIES (RESPIRATORY SYSTEM)EFFECTS ON NEWBORN (GROWTH STATISTICS)TUMORIGENIC (EQUIVOCAL TUMORIGENIC AGENT BY RTECS CRITERIA)ONLY SELECTED REGISTRY OF TOXIC EFFECTS OF CHEMICAL SUBSTANCES(RTECS) DATA IS PRESENTED HERE. SEE ACTUAL ENTRY IN RTECS FORCOMPLETE INFORMATION.SECTION 12. - - - - - - - - - ECOLOGICAL INFORMATION - - - - - - - - - -DATA NOT YET AVAILABLE.SECTION 13. - - - - - - - - - DISPOSAL CONSIDERATIONS - - - - - - - - -BURN IN A CHEMICAL INCINERATOR EQUIPPED WITH AN AFTERBURNER ANDSCRUBBER BUT EXERT EXTRA CARE IN IGNITING AS THIS MATERIAL IS HIGHLYFLAMMABLE.OBSERVE ALL FEDERAL, STATE AND LOCAL ENVIRONMENTAL REGULATIONS.SECTION 14. - - - - - - - - - - TRANSPORT INFORMATION - - - - - - - - -CONTACT FLUKA CHEMICAL COMPANY FOR TRANSPORTATION INFORMATION.SECTION 15. - - - - - - - - - REGULATORY INFORMATION - - - - - - - - - -EUROPEAN INFORMATIONEC INDEX NO: 603-002-00-5HIGHLY FLAMMABLEIRRITANTR 1HIGHLY FLAMMABLER 36/37/38IRRITATING TO EYES, RESPIRATORY SYSTEM AND SKIN.R 41RISK OF SERIOUS DAMAGE TO EYES.S 16KEEP AWAY FROM SOURCES OF IGNITION - NO SMOKING.S 26IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.S 36WEAR SUITABLE PROTECTIVE CLOTHING.TLV AND SOURCEFOR 2-PROPANOL (ISOPROPYL ALCOHOL):

ACGIH TLV-TWA: 400 PPM (983 MG/M3); STEL: 500 PPM (1230 MG/M3).OSHA PEL: 8H TWA: 400 PPM (983 MG/M3); STEL: 500 PPM (1225 MG/M3).REVIEWS, STANDARDS, AND REGULATIONSOEL=MAKACGIH TLV-NOT CLASSIFIABLE AS A HUMAN CARCINOGEN DTLVS* TLV/BEI,1999ACGIH TLV-TWA 1000 PPM DTLVS* TLV/BEI,1999IARC CANCER REVIEW:ANIMAL INADEQUATE EVIDENCE IMEMDT 44,35,1988EPA FIFRA 1988 PESTICIDE SUBJECT TO REGISTRATION OR RE-REGISTRATIONFEREAC 54,7740,1989MSHA STANDARD-AIR:TWA 1000 PPM (1900 MG/M3)DTLVS* 3,103,1971OSHA PEL (GEN INDU):8H TWA 1000 PPM (1900 MG/M3)CFRGBR 29,1910.1000,1994OSHA PEL (CONSTRUC):8H TWA 1000 PPM (1900 MG/M3)CFRGBR 29,1926.55,1994OSHA PEL (SHIPYARD):8H TWA 1000 PPM (1900 MG/M3)CFRGBR 29,1915.1000,1993OSHA PEL (FED CONT):8H TWA 1000 PPM (1900 MG/M3)CFRGBR 41,50-204.50,1994OEL-AUSTRALIA: TWA 1000 PPM (1900 MG/M3), JAN1993OEL-AUSTRIA: MAK 1000 PPM (1900 MG/M3), JAN1999OEL-BELGIUM: TWA 1000 PPM (1880 MG/M3), JAN1993OEL-DENMARK: TWA 1000 PPM (1900 MG/M3), JAN1999OEL-FINLAND: TWA 1000 PPM (1900 MG/M3), STEL 1250 PPM (2400 MG/M3),JAN1999OEL-FRANCE: VME 1000 PPM (1900 MG/M3), VLE 5000 PPM, JAN1999OEL-GERMANY: MAK 1000 PPM (1900 MG/M3), JAN1999OEL-HUNGARY: TWA 1000 MG/M3, STEL 3000 MG/M3, JAN1993OEL-THE NETHERLANDS: MAC-TGG 500 PPM (950 MG/M3), JAN1999OEL-NORWAY: TWA 500 PPM (950 MG/M3), JAN1999OEL-THE PHILIPPINES: TWA 1000 PPM (1900 MG/M3), JAN1993OEL-POLAND: MAC(TWA) 1000 MG/M3, MAC(STEL) 3000 MG/M3, JAN1999OEL-RUSSIA: STEL 1000 MG/M3, JAN1993OEL-SWEDEN: NGV 500 PPM (1000 MG/M3), KTV 1000PPM (1900 MG/M3), JAN1999OEL-SWITZERLAND: MAK-W 1000 PPM (1900 MG/M3), JAN1999OEL-THAILAND: TWA 1000 PPM (1900 MG/M3), JAN1993OEL-TURKEY: TWA 1000 PPM (1900 MG/M3), JAN1993OEL-UNITED KINGDOM: TWA 1000 PPM (1950 MG/M3), SEP2000OEL IN ARGENTINA, BULGARIA, COLOMBIA, JORDAN, KOREA CHECK ACGIH TLV;OEL IN NEW ZEALAND, SINGAPORE, VIETNAM CHECK ACGIH TLVNIOSH REL TO ETHYL ALCOHOL-AIR:10H TWA 1000 PPMNIOSH* DHHS #92-100,1992NOHS 1974: HZD 31500; NIS 430; TNF 157709; NOS 242; TNE 2088926

NOES 1983: HZD 31500; NIS 334; TNF 86077; NOS 222; TNE 2069125; TFE1014002EPA GENETOX PROGRAM 1988, POSITIVE: RODENT DOMINANT LETHALEPA GENETOX PROGRAM 1988, NEGATIVE: ASPERGILLUS-FORWARD MUTATION;SHE-CLONAL ASSAYEPA GENETOX PROGRAM 1988, NEGATIVE: CELL TRANSFORM.-RLV F344 RAT EMBRYOEPA GENETOX PROGRAM 1988, NEGATIVE: IN VITRO CYTOGENETICS-NONHUMAN;MAMMALIAN MICRONUCLEUSEPA GENETOX PROGRAM 1988, NEGATIVE: N CRASSA-ANEUPLOIDY; HISTIDINEREVERSION-AMES TESTEPA GENETOX PROGRAM 1988, NEGATIVE: IN VITRO SCE-HUMAN LYMPHOCYTES; INVITRO SCE-HUMANEPA GENETOX PROGRAM 1988, NEGATIVE: IN VITRO SCE-NONHUMAN; SPERMMORPHOLOGY-MOUSEEPA GENETOX PROGRAM 1988, NEGATIVE/LIMITED: CARCINOGENICITY-MOUSE/RATEPA TSCA SECTION 8(B) CHEMICAL INVENTORYEPA TSCA SECTION 8(D) UNPUBLISHED HEALTH/SAFETY STUDIESEPA TSCA TEST SUBMISSION (TSCATS) DATA BASE, JANUARY 2001NIOSH ANALYTICAL METHOD, 1994: ETHANOL IN BLOOD, 8002NIOSH ANALYTICAL METHOD, 1994: ALCOHOLS I, 1400NTP CARCINOGENESIS STUDIES; ON TEST (TWO YEAR STUDIES), OCTOBER 2000SECTION 16. - - - - - - - - - - OTHER INFORMATION- - - - - - - - - - - -THE ABOVE INFORMATION IS BELIEVED TO BE CORRECT BUT DOES NOT PURPORT TOBE ALL INCLUSIVE AND SHALL BE USED ONLY AS A GUIDE. SIGMA, ALDRICH,FLUKA SHALL NOT BE HELD LIABLE FOR ANY DAMAGE RESULTING FROM HANDLINGOR FROM CONTACT WITH THE ABOVE PRODUCT. SEE REVERSE SIDE OF INVOICE ORPACKING SLIP FOR ADDITIONAL TERMS AND CONDITIONS OF SALE.COPYRIGHT 2001 SIGMA-ALDRICH CO.LICENSE GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLYEasy PDF copyright (C) 1998,2000 Visage Software - http://www.visagesoft.comThis document was created with Easy PDF unregistered versionThis stamp will be removed with registered version of Easy PDFMaterial Safety Data Sheet for Iron PowderValid 05/2001 - 07/2001

Riedel-de Haen3050 Spruce St.St. Louis, MO 63178 USATel: 314-289-6000M A T E R I A L S A F E T Y D A T A S H E E TSECTION 1. - - - - - - - - - CHEMICAL IDENTIFICATION- - - - - - - - - -CATALOG #: 12311NAME: IRONSECTION 2. - - - - - COMPOSITION/INFORMATION ON INGREDIENTS - - - - - -CAS #:NONEEC NO: 231-096-4SYNONYMSANCOR EN 80/150 * ARMCO IRON * CARBONYL IRON * COPY POWDER CS 105-175* DISEASES, IRON OVERLOAD * EFV 250/400 * EO 5A * FEROVAC E * GS 6 *IRON FULLERIDE (FEC2O) * LOHA * MICROPOWDER R 2430 * NC 100 * PZH2M *PZHO * REMKO * SUY-B 2 * 3ZHP *SECTION 3. - - - - - - - - - - HAZARDS IDENTIFICATION - - - - - - - - -LABEL PRECAUTIONARY STATEMENTSFLAMMABLE (USA)HIGHLY FLAMMABLE (EU)TOXICTOXIC IF SWALLOWED.IRRITATING TO EYES.TARGET ORGAN(S):LIVERG.I. SYSTEMKEEP AWAY FROM SOURCES OF IGNITION - NO SMOKING.IN CASE OF ACCIDENT OR IF YOU FEEL UNWELL, SEEK MEDICAL ADVICEIMMEDIATELY (SHOW THE LABEL WHERE POSSIBLE).IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.WEAR SUITABLE PROTECTIVE CLOTHING, GLOVES AND EYE/FACEPROTECTION.SECTION 4. - - - - - - - - - - FIRST-AID MEASURES- - - - - - - - - - -IF SWALLOWED, WASH OUT MOUTH WITH WATER PROVIDED PERSON IS CONSCIOUS.CALL A PHYSICIAN IMMEDIATELY.IF INHALED, REMOVE TO FRESH AIR. IF NOT BREATHING GIVE ARTIFICIALRESPIRATION. IF BREATHING IS DIFFICULT, GIVE OXYGEN.IN CASE OF SKIN CONTACT, FLUSH WITH COPIOUS AMOUNTS OF WATERFOR AT LEAST 15 MINUTES. REMOVE CONTAMINATED CLOTHING ANDSHOES. CALL A PHYSICIAN.IN CASE OF CONTACT WITH EYES, FLUSH WITH COPIOUS AMOUNTS OF WATER

FOR AT LEAST 15 MINUTES. ASSURE ADEQUATE FLUSHING BY SEPARATINGTHE EYELIDS WITH FINGERS. CALL A PHYSICIAN.SECTION 5. - - - - - - - - - FIRE FIGHTING MEASURES - - - - - - - - - -EXTINGUISHING MEDIAWATER SPRAY.CARBON DIOXIDE, DRY CHEMICAL POWDER OR APPROPRIATE FOAM.SPECIAL FIREFIGHTING PROCEDURESWEAR SELF-CONTAINED BREATHING APPARATUS AND PROTECTIVE CLOTHING TOPREVENT CONTACT WITH SKIN AND EYES.UNUSUAL FIRE AND EXPLOSIONS HAZARDSEMITS TOXIC FUMES UNDER FIRE CONDITIONS.THIS MATERIAL, LIKE MOST MATERIALS IN POWDER FORM, IS CAPABLE OFCREATING A DUST EXPLOSION.SECTION 6. - - - - - - - - ACCIDENTAL RELEASE MEASURES- - - - - - - - -WEAR SELF-CONTAINED BREATHING APPARATUS, RUBBER BOOTS AND HEAVYRUBBER GLOVES.SWEEP UP, PLACE IN A BAG AND HOLD FOR WASTE DISPOSAL.AVOID RAISING DUST.VENTILATE AREA AND WASH SPILL SITE AFTER MATERIAL PICKUP IS COMPLETE.EVACUATE AREA.USE NONSPARKING TOOLS.SHUT OFF ALL SOURCES OF IGNITION.SECTION 7. - - - - - - - - - - HANDLING AND STORAGE- - - - - - - - - - -REFER TO SECTION 8.SECTION 8. - - - - - - EXPOSURE CONTROLS/PERSONAL PROTECTION- - - - - -WASH CONTAMINATED CLOTHING BEFORE REUSE.WASH THOROUGHLY AFTER HANDLING.DO NOT BREATHE DUST.DO NOT GET IN EYES, ON SKIN, ON CLOTHING.AVOID PROLONGED OR REPEATED EXPOSURE.NIOSH/MSHA-APPROVED RESPIRATOR. COMPATIBLE CHEMICAL-RESISTANT GLOVES.CHEMICAL SAFETY GOGGLES.SAFETY SHOWER AND EYE BATH.USE NONSPARKING TOOLS.MECHANICAL EXHAUST REQUIRED.KEEP TIGHTLY CLOSED.KEEP AWAY FROM HEAT, SPARKS, AND OPEN FLAME.STORE IN A COOL DRY PLACE.STORE UNDER N2.SECTION 9. - - - - - - - PHYSICAL AND CHEMICAL PROPERTIES - - - - - - -APPEARANCE AND ODOR

SOLID.PHYSICAL PROPERTIESSPECIFIC GRAVITY: 7.86SECTION 10. - - - - - - - - -STABILITY AND REACTIVITY - - - - - - - - -STABILITYSTABLE.INCOMPATIBILITIESREACTS VIOLENTLY WITH:HALOGENSPHOSPHORUSPROTECT FROM MOISTURE.ACIDSOXYGENSTRONG OXIDIZING AGENTSHAZARDOUS COMBUSTION OR DECOMPOSITION PRODUCTSIRON OXIDESHAZARDOUS POLYMERIZATION WILL NOT OCCUR.SECTION 11 - - TOXICOLOGICAL INFORMATION - - ACUTE EFFECTSOVERDOSE OF IRON COMPOUNDS MAY HAVE A CORROSIVE EFFECT ON THE GASTROINTESTINAL MUCOSA AND BE FOLLOWED BY NECROSIS, PERFORATION AND STRICTURE FORMATION. SEVERAL HOURS MAY ELAPSE BEFORE SYMPTOMS THAT CAN INCLUDE EPIGASTRIC PAIN, DIARRHEA, VOMITING, NAUSEA AND HEMATEMESIS OCCUR. AFTER APPARENT RECOVERY A PERSON MAY EXPERIENCE METABOLIC ACIDOSIS, CONVULSIONS AND COMA HOURS OR DAYS LATER. FURTHERCOMPLICATIONS MAY DEVELOP LEADING TO ACUTE LIVER NECROSIS THAT CAN RESULT IN DEATH DUE TO HEPATIC COMA.LONG TERM INHALATION EXPOSURE TO IRON (OXIDE FUME OR DUST) CAN CAUSE SIDEROSIS. SIDEROSIS IS CONSIDERED TO BE A BENIGN PNEUMOCONIOSIS AND DOES NOT NORMALLY CAUSE SIGNIFICANT PHYSIOLOGIC IMPAIRMENT. SIDEROSIS CAN BE OBSERVED ON X-RAYS WITH THE LUNGS HAVING A MOTTLED APPEARANCE.EXPOSURE CAN CAUSE:STUPOR, SHOCK, ABDOMINAL CRAMPS, VOMITING, BURNING EPIGASTRIC DISTRESS, CENTRAL NERVOUS SYSTEM AND CARDIOVASCULAR DISTURBANCES, CYANOSIS, LEUKOCYTOSIS, HYPERGLYCEMIA, LETHARGY, AND PULMONARY EDEMA. MAY CAUSE SKIN IRRITATION.MAY BE HARMFUL IF ABSORBED THROUGH THE SKIN.CAUSES EYE IRRITATION. MAY BE HARMFUL IF INHALED.MATERIAL MAY BE IRRITATING TO MUCOUS MEMBRANES AND UPPER RESPIRATORY TRACT.TOXIC IF SWALLOWED.CHRONIC EFFECTSTARGET ORGAN(S):LIVERG.I. SYSTEM

BLOODCARDIOVASCULAR SYSTEMRTECS #: NO4565500IRONTOXICITY DATAORL-RAT LD50:30 GM/KG IJPAAO 13,240,1951ORL-GPG LD50:20 GM/KG IJPAAO 13,240,1951TARGET ORGAN DATABEHAVIORAL (IRRITABILITY)LUNGS, THORAX OR RESPIRATION (TUMORS)GASTROINTESTINAL (NAUSEA OR VOMITING)BLOOD (NORMOCYTIC ANEMIA)TUMORIGENIC (EQUIVOCAL TUMORIGENIC AGENT BY RTECS CRITERIA)ADDITIONAL INFORMATIONORL-CHD LDL0:77 MG/KGORL-HMN LDLO:70 MG/KGONLY SELECTED REGISTRY OF TOXIC EFFECTS OF CHEMICAL SUBSTANCES(RTECS) DATA IS PRESENTED HERE. SEE ACTUAL ENTRY IN RTECS FORCOMPLETE INFORMATION.SECTION 12. - - - - - - - - - ECOLOGICAL INFORMATION - - - - - - - - - -DATA NOT YET AVAILABLE.SECTION 13. - - - - - - - - - DISPOSAL CONSIDERATIONS - - - - - - - - -MATERIAL IN THE ELEMENTAL STATE SHOULD BE RECOVERED FOR REUSE ORRECYCLING.OBSERVE ALL FEDERAL, STATE AND LOCAL ENVIRONMENTAL REGULATIONS.SECTION 14. - - - - - - - - - - TRANSPORT INFORMATION - - - - - - - - -CONTACT SIGMA CHEMICAL COMPANY FOR TRANSPORTATION INFORMATION.SECTION 15. - - - - - - - - - REGULATORY INFORMATION - - - - - - - - - -EUROPEAN INFORMATIONHIGHLY FLAMMABLE TOXICR 25TOXIC IF SWALLOWED.R 36IRRITATING TO EYES.S 16KEEP AWAY FROM SOURCES OF IGNITION - NO SMOKING.S 45IN CASE OF ACCIDENT OR IF YOU FEEL UNWELL, SEEK MEDICAL ADVICEIMMEDIATELY (SHOW THE LABEL WHERE POSSIBLE).S 26IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.S 36/37/39

WEAR SUITABLE PROTECTIVE CLOTHING, GLOVES AND EYE/FACE PROTECTION.REVIEWS, STANDARDS, AND REGULATIONSOEL=MAKNOHS 1974: HZD 91095; NIS 160; TNF 13096; NOS 115; TNE 207672NOES 1983: HZD T0176; NIS 130; TNF 13865; NOS 72; TNE 204603; TFE 16574NOES 1983: HZD X3724; NIS 1; TNF 122; NOS 2; TNE 1670NOES 1983: HZD X5910; NIS 1; TNF 3; NOS 1; TNE 400; TFE 400NOES 1983: HZD X5996; NIS 1; TNF 45; NOS 1; TNE 179NOES 1983: HZD 91095; NIS 364; TNF 103949; NOS 174; TNE 1312446; TFE116899EPA TSCA SECTION 8(B) CHEMICAL INVENTORYEPA TSCA SECTION 8(D) UNPUBLISHED HEALTH/SAFETY STUDIESEPA TSCA TEST SUBMISSION (TSCATS) DATA BASE, JANUARY 2001NIOSH ANALYTICAL METHOD, 1994: METALS IN URINE, 8310NIOSH ANALYTICAL METHOD, 1994: ELEMENTS IN BLOOD OR TISSUE, 8005SECTION 16. - - - - - - - - - - OTHER INFORMATION- - - - - - - - - - - -THE ABOVE INFORMATION IS BELIEVED TO BE CORRECT BUT DOES NOT PURPORT TOBE ALL INCLUSIVE AND SHALL BE USED ONLY AS A GUIDE. SIGMA, ALDRICH, FLUKA SHALL NOT BE HELD LIABLE FOR ANY DAMAGE RESULTING FROM HANDLING OR FROM CONTACT WITH THE ABOVE PRODUCT. SEE REVERSE SIDE OF INVOICE OR PACKING SLIP FOR ADDITIONAL TERMS AND CONDITIONS OF SALE.COPYRIGHT 2001 SIGMA-ALDRICH CO.LICENSE GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLYMaterial Safety Data Sheet for Palladium PowderValid 05/2001 - 07/2001Riedel-de Haen 3050 Spruce St. St. Louis, MO 63178 USA Tel: 314-289-6000M A T E R I A L S A F E T Y D A T A S H E E TSECTION 1. - - - - - - - - - CHEMICAL IDENTIFICATION- - - - - - - - - -CATALOG #: 64149NAME: PALLADIUM (PALLADIUM BLACK) 98%SECTION 2. - - - - - COMPOSITION/INFORMATION ON INGREDIENTS - - - - - -CAS #: 7440-05-3MF: PDMEC NO: 231-115-6SYNONYMSPALLADEX 600 * PALLADIUM BLACK * PALLADIUM ELEMENT *SECTION 3. - - - - - - - - - - HAZARDS IDENTIFICATION - - - - - - - - -LABEL PRECAUTIONARY STATEMENTSPYROPHORIC (USA DEFINITION)HIGHLY FLAMMABLE (EUROPEAN DEFINITION)IRRITANTIRRITATING TO EYES, RESPIRATORY SYSTEM AND SKIN.KEEP AWAY FROM SOURCES OF IGNITION - NO SMOKING.

IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.WEAR SUITABLE PROTECTIVE CLOTHING.KEEP CONTAINER TIGHTLY CLOSED AND IN WELL-VENTILATED PLACE.SECTION 4. - - - - - - - - - - FIRST-AID MEASURES- - - - - - - - - - -IF SWALLOWED, WASH OUT MOUTH WITH WATER PROVIDED PERSON IS CONSCIOUS.CALL A PHYSICIAN.IF INHALED, REMOVE TO FRESH AIR. IF NOT BREATHING GIVE ARTIFICIAL RESPIRATION.IF BREATHING IS DIFFICULT, GIVE OXYGEN.IN CASE OF SKIN CONTACT, FLUSH WITH COPIOUS AMOUNTS OF WATERFOR AT LEAST 15 MINUTES. REMOVE CONTAMINATED CLOTHING AND SHOES. CALL A PHYSICIAN.IN CASE OF CONTACT WITH EYES, FLUSH WITH COPIOUS AMOUNTS OF WATERFOR AT LEAST 15 MINUTES. ASSURE ADEQUATE FLUSHING BY SEPARATING THE EYELIDS WITH FINGERS. CALL A PHYSICIAN.SECTION 5. - - - - - - - - - FIRE FIGHTING MEASURES - - - - - - - - - -EXTINGUISHING MEDIA WATER SPRAY.CARBON DIOXIDE, DRY CHEMICAL POWDER OR APPROPRIATE FOAM.SPECIAL FIREFIGHTING PROCEDURESWEAR SELF-CONTAINED BREATHING APPARATUS AND PROTECTIVE CLOTHING TOPREVENT CONTACT WITH SKIN AND EYES.UNUSUAL FIRE AND EXPLOSIONS HAZARDSPYROPHORIC MATERIAL.EMITS TOXIC FUMES UNDER FIRE CONDITIONS.CATCHES FIRE IF EXPOSED TO AIR.SECTION 6. - - - - - - - - ACCIDENTAL RELEASE MEASURES- - - - - - - - -WEAR SELF-CONTAINED BREATHING APPARATUS, RUBBER BOOTS AND HEAVYRUBBER GLOVES.AVOID RAISING DUST.COVER WITH DRY-LIME, SAND, OR SODA ASH. PLACE IN COVERED CONTAINERS USING NON-SPARKING TOOLS AND TRANSPORT OUTDOORS.VENTILATE AREA AND WASH SPILL SITE AFTER MATERIAL PICKUP IS COMPLETE.EVACUATE AREA.SHUT OFF ALL SOURCES OF IGNITION.USE NONSPARKING TOOLS.SECTION 7. - - - - - - - - - - HANDLING AND STORAGE- - - - - - - - - - -REFER TO SECTION 8.SECTION 8. - - - - - - EXPOSURE CONTROLS/PERSONAL PROTECTION- - - - - -SAFETY SHOWER AND EYE BATH.USE NONSPARKING TOOLS.

MECHANICAL EXHAUST REQUIRED.WASH THOROUGHLY AFTER HANDLING.AVOID CONTACT WITH EYES, SKIN AND CLOTHING.AVOID BREATHING DUST.AVOID PROLONGED OR REPEATED EXPOSURE.NIOSH/MSHA-APPROVED RESPIRATOR.COMPATIBLE CHEMICAL-RESISTANT GLOVES.CHEMICAL SAFETY GOGGLES.KEEP CONTAINER CLOSED.KEEP AWAY FROM HEAT, SPARKS, AND OPEN FLAME.HANDLE AND STORE UNDER NITROGEN.SECTION 9. - - - - - - - PHYSICAL AND CHEMICAL PROPERTIES - - - - - - -APPEARANCE AND ODORSOLID.SECTION 10. - - - - - - - - -STABILITY AND REACTIVITY - - - - - - - - -STABILITYSTABLE.INCOMPATIBILITIESCATCHES FIRE IF EXPOSED TO AIR.STRONG OXIDIZING AGENTSHAZARDOUS COMBUSTION OR DECOMPOSITION PRODUCTSCARBON MONOXIDE, CARBON DIOXIDEHAZARDOUS POLYMERIZATIONWILL NOT OCCUR.SECTION 11. - - - - - - - - - TOXICOLOGICAL INFORMATION - - - - - - - -ACUTE EFFECTSTO THE BEST OF OUR KNOWLEDGE, THE CHEMICAL, PHYSICAL, ANDTOXICOLOGICAL PROPERTIES HAVE NOT BEEN THOROUGHLY INVESTIGATED.MAY CAUSE SKIN IRRITATION.MAY BE HARMFUL IF ABSORBED THROUGH THE SKIN.MAY CAUSE EYE IRRITATION.MAY BE HARMFUL IF INHALED.MATERIAL MAY BE IRRITATING TO MUCOUS MEMBRANES AND UPPERRESPIRATORY TRACT.MAY BE HARMFUL IF SWALLOWED.RTECS #: RT3480500PALLADIUMONLY SELECTED REGISTRY OF TOXIC EFFECTS OF CHEMICAL SUBSTANCES(RTECS) DATA IS PRESENTED HERE. SEE ACTUAL ENTRY IN RTECS FORCOMPLETE INFORMATION.SECTION 12. - - - - - - - - - ECOLOGICAL INFORMATION - - - - - - - - - -DATA NOT YET AVAILABLE.SECTION 13. - - - - - - - - - DISPOSAL CONSIDERATIONS - - - - - - - - -CONTACT A LICENSED PROFESSIONAL WASTE DISPOSAL SERVICE TO DISPOSE OF

THIS MATERIAL.BURN IN A CHEMICAL INCINERATOR EQUIPPED WITH AN AFTERBURNER ANDSCRUBBER BUT EXERT EXTRA CARE IN IGNITING AS THIS MATERIAL IS HIGHLYFLAMMABLE.OBSERVE ALL FEDERAL, STATE AND LOCAL ENVIRONMENTAL REGULATIONS.SECTION 14. - - - - - - - - - - TRANSPORT INFORMATION - - - - - - - - -CONTACT SIGMA CHEMICAL COMPANY FOR TRANSPORTATION INFORMATION.SECTION 15. - - - - - - - - - REGULATORY INFORMATION - - - - - - - - - -EUROPEAN INFORMATIONHIGHLY FLAMMABLEIRRITANTR 36/37/38IRRITATING TO EYES, RESPIRATORY SYSTEM AND SKIN.S 16KEEP AWAY FROM SOURCES OF IGNITION - NO SMOKING.S 26IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.S 36WEAR SUITABLE PROTECTIVE CLOTHING.S 7/9KEEP CONTAINER TIGHTLY CLOSED AND IN WELL-VENTILATED PLACE.REVIEWS, STANDARDS, AND REGULATIONSOEL=MAKEPA TSCA SECTION 8(B) CHEMICAL INVENTORYEPA TSCA TEST SUBMISSION (TSCATS) DATA BASE, JANUARY 2001U.S. INFORMATIONTHIS PRODUCT IS SUBJECT TO SARA SECTION 313 REPORTING REQUIREMENTS.SECTION 16. - - - - - - - - - - OTHER INFORMATION- - - - - - - - - - - -THE ABOVE INFORMATION IS BELIEVED TO BE CORRECT BUT DOES NOT PURPORT TOBE ALL INCLUSIVE AND SHALL BE USED ONLY AS A GUIDE. SIGMA, ALDRICH,FLUKA SHALL NOT BE HELD LIABLE FOR ANY DAMAGE RESULTING FROM HANDLING OR FROM CONTACT WITH THE ABOVE PRODUCT. SEE REVERSE SIDE OF INVOICE OR PACKING SLIP FOR ADDITIONAL TERMS AND CONDITIONS OF SALE.COPYRIGHT 2001 SIGMA-ALDRICH CO.LICENSE GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLYMaterial Safety Data Sheet for Tetraethoxysilane (Tetraethyl Orthosilicate)Valid 05/2001 - 07/2001

Aldrich Chemical Co., Inc. 1001 West St. Paul Milwaukee, WI 53233 USA Tel: 414-273-3850M A T E R I A L S A F E T Y D A T A S H E E TSECTION 1. - - - - - - - - - CHEMICAL IDENTIFICATION- - - - - - - - - -CATALOG #: 131903NAME: TETRAETHYL ORTHOSILICATE, 98%SECTION 2. - - - - - COMPOSITION/INFORMATION ON INGREDIENTS - - - - - -CAS #: 78-10-4MF: C8H20O4SIEC NO: 201-083-8SYNONYMSETHYL ORTHOSILICATE * ETHYL SILICATE (ACGIH:OSHA) * ETYLU KRZEMIAN(POLISH) * SILANE, TETRAETHOXY- * SILICATE D'ETHYLE (FRENCH) *SILICATE TETRAETHYLIQUE (FRENCH) * TEOS * TETRAETHOXYSILANE *TETRAETHYL ORTHOSILICATE * TETRAETHYLSILIKAT (CZECH) *SECTION 3. - - - - - - - - - - HAZARDS IDENTIFICATION - - - - - - - - -LABEL PRECAUTIONARY STATEMENTSCOMBUSTIBLE (USA)FLAMMABLE (EU)HARMFULHARMFUL BY INHALATION, IN CONTACT WITH SKIN AND IF SWALLOWED.IRRITATING TO EYES, RESPIRATORY SYSTEM AND SKIN.TARGET ORGAN(S):LIVERKIDNEYSLUNGSBLOODKEEP AWAY FROM SOURCES OF IGNITION - NO SMOKING.IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.WEAR SUITABLE PROTECTIVE CLOTHING, GLOVES AND EYE/FACEPROTECTION.MOISTURE SENSITIVESTORE UNDER NITROGEN.SECTION 4. - - - - - - - - - - FIRST-AID MEASURES- - - - - - - - - - -IN CASE OF CONTACT, IMMEDIATELY FLUSH EYES WITH COPIOUS AMOUNTS OFWATER FOR AT LEAST 15 MINUTES.IN CASE OF CONTACT, IMMEDIATELY WASH SKIN WITH SOAP AND COPIOUSAMOUNTS OF WATER.IF INHALED, REMOVE TO FRESH AIR. IF NOT BREATHING GIVE ARTIFICIALRESPIRATION. IF BREATHING IS DIFFICULT, GIVE OXYGEN.IF SWALLOWED, WASH OUT MOUTH WITH WATER PROVIDED PERSON IS CONSCIOUS.CALL A PHYSICIAN.

REMOVE AND WASH CONTAMINATED CLOTHING PROMPTLY.SECTION 5. - - - - - - - - - FIRE FIGHTING MEASURES - - - - - - - - - -EXTINGUISHING MEDIACARBON DIOXIDE, DRY CHEMICAL POWDER OR APPROPRIATE FOAM.SPECIAL FIREFIGHTING PROCEDURESWEAR SELF-CONTAINED BREATHING APPARATUS AND PROTECTIVE CLOTHING TO PREVENT CONTACT WITH SKIN AND EYES.COMBUSTIBLE.UNUSUAL FIRE AND EXPLOSIONS HAZARDSVAPOR MAY TRAVEL CONSIDERABLE DISTANCE TO SOURCE OF IGNITION AND FLASH BACK.UNDER FIRE CONDITIONS, MATERIAL MAY DECOMPOSETO FORM FLAMMABLE AND/OR EXPLOSIVE MIXTURES IN AIR.EMITS TOXIC FUMES UNDER FIRE CONDITIONS.SECTION 6. - - - - - - - - ACCIDENTAL RELEASE MEASURES- - - - - - - - -EVACUATE AREA.WEAR SELF-CONTAINED BREATHING APPARATUS, RUBBER BOOTS AND HEAVYRUBBER GLOVES.ABSORB ON SAND OR VERMICULITE AND PLACE IN CLOSED CONTAINERS FORDISPOSAL.VENTILATE AREA AND WASH SPILL SITE AFTER MATERIAL PICKUP IS COMPLETE.SECTION 7. - - - - - - - - - - HANDLING AND STORAGE- - - - - - - - - - -REFER TO SECTION 8.SECTION 8. - - - - - - EXPOSURE CONTROLS/PERSONAL PROTECTION- - - - - -WEAR APPROPRIATE NIOSH/MSHA-APPROVED RESPIRATOR, CHEMICAL-RESISTANTGLOVES, SAFETY GOGGLES, OTHER PROTECTIVE CLOTHING.SAFETY SHOWER AND EYE BATH.MECHANICAL EXHAUST REQUIRED.DO NOT BREATHE VAPOR.DO NOT GET IN EYES, ON SKIN, ON CLOTHING.WASH THOROUGHLY AFTER HANDLING.HARMFUL LIQUID.IRRITANT.KEEP TIGHTLY CLOSED.MOISTURE SENSITIVEKEEP AWAY FROM HEAT AND OPEN FLAME.STORE UNDER NITROGEN.STORE IN A COOL DRY PLACE.SECTION 9. - - - - - - - PHYSICAL AND CHEMICAL PROPERTIES - - - - - - -APPEARANCE AND ODORCOLORLESS LIQUIDPHYSICAL PROPERTIES

BOILING POINT: 168 CFLASHPOINT 116F46.66CVAPOR PRESSURE: <1MM 20 CSPECIFIC GRAVITY: 0.934VAPOR DENSITY: >1SECTION 10. - - - - - - - - -STABILITY AND REACTIVITY - - - - - - - - -INCOMPATIBILITIESSTRONG OXIDIZING AGENTSSTRONG ACIDSMAY DECOMPOSE ON EXPOSURE TO MOIST AIR OR WATER.HAZARDOUS COMBUSTION OR DECOMPOSITION PRODUCTSTOXIC FUMES OF:CARBON MONOXIDE, CARBON DIOXIDESILICON OXIDESECTION 11. - - - - - - - - - TOXICOLOGICAL INFORMATION - - - - - - - -ACUTE EFFECTSHARMFUL IF SWALLOWED, INHALED, OR ABSORBED THROUGH SKIN.CAUSES SKIN IRRITATION.VAPOR OR MIST IS IRRITATING TO THE EYES, MUCOUS MEMBRANES AND UPPERRESPIRATORY TRACT.EXPOSURE CAN CAUSE:NAUSEA, HEADACHE AND VOMITINGTO THE BEST OF OUR KNOWLEDGE, THE CHEMICAL, PHYSICAL, ANDTOXICOLOGICAL PROPERTIES HAVE NOT BEEN THOROUGHLY INVESTIGATED.CHRONIC EFFECTSPROLONGED EXPOSURE CAN CAUSE:LUNG IRRITATION, CHEST PAIN AND EDEMA WHICH MAY BE FATAL.TARGET ORGAN(S):LIVERKIDNEYSLUNGSBLOODRTECS #: VV9450000SILICIC ACID, TETRAETHYL ESTERIRRITATION DATAEYE-HMN 3000 PPM JIHTAB 22,288,1940SKN-RBT 500 MG/24H MOD UCDS** 7/23/1970EYE-RBT 100 MG MLD UCDS** 7/23/1970EYE-RBT 500 MG/24H MLD 85JCAE -,1231,1986EYE-GPG 2500 PPM/2H SEV JIHTAB 22,288,1940TOXICITY DATAORL-RAT LD50:6270 MG/KG JIHTAB 31,60,1949SKN-RBT LD50:6300 UL/KG UCDS** 7/23/1970TARGET ORGAN DATA

BEHAVIORAL (GENERAL ANESTHETIC)LUNGS, THORAX OR RESPIRATION (CHANGE IN TRACHEA OR BRONCHI)LUNGS, THORAX OR RESPIRATION (ACUTE PULMONARY EDEMA)LUNGS, THORAX OR RESPIRATION (PLEURAL EFFUSION)KIDNEY, URETER, BLADDER (CHANGES IN TUBULES)KIDNEY, URETER, BLADDER (INTERSTITIAL NEPHRITIS)BLOOD (OTHER HEMOLYSIS WITH OR WITHOUT ANEMIA)BLOOD (CHANGES IN SPLEEN)NUTRITIONAL AND GROSS METABOLIC (WEIGHT LOSS OR DECREASED WEIGHT GAIN)ONLY SELECTED REGISTRY OF TOXIC EFFECTS OF CHEMICAL SUBSTANCES(RTECS) DATA IS PRESENTED HERE. SEE ACTUAL ENTRY IN RTECS FORCOMPLETE INFORMATION.SECTION 12. - - - - - - - - - ECOLOGICAL INFORMATION - - - - - - - - - -DATA NOT YET AVAILABLE.SECTION 13. - - - - - - - - - DISPOSAL CONSIDERATIONS - - - - - - - - -THIS COMBUSTIBLE MATERIAL MAY BE BURNED IN A CHEMICAL INCINERATOREQUIPPED WITH AN AFTERBURNER AND SCRUBBER.OBSERVE ALL FEDERAL, STATE AND LOCAL ENVIRONMENTAL REGULATIONS.SECTION 14. - - - - - - - - - - TRANSPORT INFORMATION - - - - - - - - -CONTACT ALDRICH CHEMICAL COMPANY FOR TRANSPORTATION INFORMATION.SECTION 15. - - - - - - - - - REGULATORY INFORMATION - - - - - - - - - -EUROPEAN INFORMATIONEC INDEX NO: 014-005-00-0FLAMMABLEHARMFULR 10FLAMMABLE.R 20HARMFUL BY INHALATION.R 36/37IRRITATING TO EYES AND RESPIRATORY SYSTEM.REVIEWS, STANDARDS, AND REGULATIONSOEL=MAKACGIH TLV-TWA 10 PPM DTLVS* TLV/BEI,1999MSHA STANDARD-AIR:TWA 100 PPM (850 MG/M3)DTLVS* 3,108,1971OSHA PEL (GEN INDU):8H TWA 100 PPM (850 MG/M3)CFRGBR 29,1910.1000,1994OSHA PEL (CONSTRUC):8H TWA 100 PPM (850 MG/M3)CFRGBR 29,1926.55,1994OSHA PEL (SHIPYARD):8H TWA 100 PPM (850 MG/M3)CFRGBR 29,1915.1000,1993

OSHA PEL (FED CONT):8H TWA 100 PPM (850 MG/M3)CFRGBR 41,50-204.50,1994OEL-AUSTRALIA: TWA 10 PPM (85 MG/M3), JAN1993OEL-AUSTRIA: MAK 20 PPM (170 MG/M3), JAN1999OEL-BELGIUM: TWA 10 PPM (85 MG/M3), JAN1993OEL-DENMARK: TWA 10 PPM (85 MG/M3), JAN1999OEL-FINLAND: TWA 10 PPM (85 MG/M3), STEL 20 PPM (170 MG/M3), JAN1999OEL-FRANCE: VME 10 PPM (85 MG/M3), JAN1999OEL-GERMANY: MAK 20 PPM (170 MG/M3), JAN1999OEL-JAPAN: OEL 10 PPM (85 MG/M3), JAN1999OEL-THE NETHERLANDS: MAC-TGG 10 PPM (85 MG/M3), JAN1999OEL-NORWAY: TWA 10 PPM (85 MG/M3), JAN1999OEL-THE PHILIPPINES: TWA 100 PPM (850 MG/M3), JAN1993OEL-POLAND: MAC(TWA) 80 MG/M3, MAC(STEL) 250 MG/M3, JAN1999OEL-RUSSIA: STEL 20 MG/M3, JAN1993OEL-SWITZERLAND: MAK-W 10 PPM (85 MG/M3), JAN1999OEL-TURKEY: TWA 100 PPM (850 MG/M3), JAN1993OEL-UNITED KINGDOM: TWA 10 PPM (87 MG/M3), STEL 30 PPM, SEP2000OEL IN ARGENTINA, BULGARIA, COLOMBIA, JORDAN, KOREA CHECK ACGIH TLV; OEL IN NEW ZEALAND, SINGAPORE, VIETNAM CHECK ACGIH TLVNIOSH REL TO ETHYL SILICATE-AIR:10H TWA 10 PPMNIOSH* DHHS #92-100,1992NOES 1983: HZD X4097; NIS 22; TNF 721; NOS 26; TNE 10422; TFE 2566EPA TSCA SECTION 8(B) CHEMICAL INVENTORYEPA TSCA TEST SUBMISSION (TSCATS) DATA BASE, JANUARY 2001SECTION 16. - - - - - - - - - - OTHER INFORMATION- - - - - - - - - - - -THE ABOVE INFORMATION IS BELIEVED TO BE CORRECT BUT DOES NOT PURPORT TOBE ALL INCLUSIVE AND SHALL BE USED ONLY AS A GUIDE. SIGMA, ALDRICH,FLUKA SHALL NOT BE HELD LIABLE FOR ANY DAMAGE RESULTING FROM HANDLING OR FROM CONTACT WITH THE ABOVE PRODUCT. SEE REVERSE SIDE OF INVOICE OR PACKING SLIP FOR ADDITIONAL TERMS AND CONDITIONS OF SALE.COPYRIGHT 2001 SIGMA-ALDRICH CO.LICENSE GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLYMaterial Safety Data Sheet for TetramethoxysilaneValid 05/2001 - 07/2001Fluka Chemical Corp.1001 West St. PaulMilwaukee, WI 53233 USATel: 414-273-3850M A T E R I A L S A F E T Y D A T A S H E E TSECTION 1. - - - - - - - - - CHEMICAL IDENTIFICATION- - - - - - - - - -CATALOG #: 87682

NAME: TETRAMETHOXYSILANESECTION 2. - - - - - COMPOSITION/INFORMATION ON INGREDIENTS - - - - - -CAS #: 681-84-5MF: C4H12O4SIEC NO: 211-656-4SYNONYMSMETHYL SILICATE (ACGIH) * SILICIC ACID, METHYL ESTER OF ORTHO- *TETRAMETHOXYSILANE * TETRAMETHYL SILICATE * TETRAMETHYLSILIKAT (CZECH)* TL 190 *SECTION 3. - - - - - - - - - - HAZARDS IDENTIFICATION - - - - - - - - -LABEL PRECAUTIONARY STATEMENTSFLAMMABLEHIGHLY TOXIC (USA)TOXIC (EU)TOXIC BY INHALATION.CAUSES BURNS.TARGET ORGAN(S):EYESKIDNEYSKEEP AWAY FROM SOURCES OF IGNITION - NO SMOKING.IN CASE OF ACCIDENT OR IF YOU FEEL UNWELL, SEEK MEDICAL ADVICEIMMEDIATELY (SHOW THE LABEL WHERE POSSIBLE).IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.WEAR SUITABLE PROTECTIVE CLOTHING, GLOVES AND EYE/FACEPROTECTION.SECTION 4. - - - - - - - - - - FIRST-AID MEASURES- - - - - - - - - - -IN CASE OF CONTACT, IMMEDIATELY FLUSH EYES OR SKIN WITH COPIOUSAMOUNTS OF WATER FOR AT LEAST 15 MINUTES WHILE REMOVING CONTAMINATEDCLOTHING AND SHOES.IF SWALLOWED, WASH OUT MOUTH WITH WATER PROVIDED PERSON IS CONSCIOUS.CALL A PHYSICIAN IMMEDIATELY.IF INHALED, REMOVE TO FRESH AIR. IF NOT BREATHING GIVE ARTIFICIALRESPIRATION. IF BREATHING IS DIFFICULT, GIVE OXYGEN.ASSURE ADEQUATE FLUSHING OF THE EYES BY SEPARATING THE EYELIDSWITH FINGERS.SECTION 5. - - - - - - - - - FIRE FIGHTING MEASURES - - - - - - - - - -EXTINGUISHING MEDIACARBON DIOXIDE, DRY CHEMICAL POWDER OR APPROPRIATE FOAM.WATER MAY BE EFFECTIVE FOR COOLING, BUT MAY NOT EFFECT EXTINGUISHMENT.SPECIAL FIREFIGHTING PROCEDURES

WEAR SELF-CONTAINED BREATHING APPARATUS AND PROTECTIVE CLOTHING TOPREVENT CONTACT WITH SKIN AND EYES.USE WATER SPRAY TO COOL FIRE-EXPOSED CONTAINERS.UNUSUAL FIRE AND EXPLOSIONS HAZARDSFLAMMABLE LIQUID.VAPOR MAY TRAVEL CONSIDERABLE DISTANCE TO SOURCE OF IGNITION ANDFLASH BACK.CONTAINER EXPLOSION MAY OCCUR UNDER FIRE CONDITIONS.FORMS EXPLOSIVE MIXTURES IN AIR.SECTION 6. - - - - - - - - ACCIDENTAL RELEASE MEASURES- - - - - - - - -EVACUATE AREA.SHUT OFF ALL SOURCES OF IGNITION.WEAR SELF-CONTAINED BREATHING APPARATUS, RUBBER BOOTS AND HEAVYRUBBER GLOVES.COVER WITH AN ACTIVATED CARBON ADSORBENT, TAKE UP AND PLACE IN CLOSEDCONTAINERS. TRANSPORT OUTDOORS.VENTILATE AREA AND WASH SPILL SITE AFTER MATERIAL PICKUP IS COMPLETE.SECTION 7. - - - - - - - - - - HANDLING AND STORAGE- - - - - - - - - - -REFER TO SECTION 8.SECTION 8. - - - - - - EXPOSURE CONTROLS/PERSONAL PROTECTION- - - - - -WEAR APPROPRIATE NIOSH/MSHA-APPROVED RESPIRATOR, CHEMICAL-RESISTANTGLOVES, SAFETY GOGGLES, OTHER PROTECTIVE CLOTHING.FACESHIELD (8-INCH MINIMUM).USE ONLY IN A CHEMICAL FUME HOOD.SAFETY SHOWER AND EYE BATH.USE NONSPARKING TOOLS.DO NOT BREATHE VAPOR.DO NOT GET IN EYES, ON SKIN, ON CLOTHING.WASH THOROUGHLY AFTER HANDLING.DISCARD CONTAMINATED CLOTHING AND SHOES.KEEP TIGHTLY CLOSED.KEEP AWAY FROM HEAT, SPARKS, AND OPEN FLAME.STORE IN A COOL DRY PLACE.SECTION 9. - - - - - - - PHYSICAL AND CHEMICAL PROPERTIES - - - - - - -PHYSICAL PROPERTIESBOILING POINT: 120 - 122 CMELTING POINT: -4 CFLASHPOINT 78.8 F26 CVAPOR PRESSURE: 274.527 MMHG

SPECIFIC GRAVITY: 1.032VAPOR DENSITY: 5.25 G/LSECTION 10. - - - - - - - - -STABILITY AND REACTIVITY - - - - - - - - -STABILITYSTABLE.CONDITIONS TO AVOIDMAY DECOMPOSE ON EXPOSURE TO MOIST AIR OR WATER.INCOMPATIBILITIESOXIDIZING AGENTSACIDSBASESHAZARDOUS COMBUSTION OR DECOMPOSITION PRODUCTSCARBON MONOXIDE, CARBON DIOXIDESILICON OXIDEMETHANOLHAZARDOUS POLYMERIZATIONWILL NOT OCCUR.SECTION 11. - - - - - - - - - TOXICOLOGICAL INFORMATION - - - - - - - -ACUTE EFFECTSWARNING: AVOID EYE CONTACT BECAUSE TETRAMETHYL ORTHOSILICATEUNDERGOES HYDROLYSIS READILY, PRODUCING METHANOL WHICH CAUSESIRREVERSIBLE BLINDNESS.CONTACT WITH MOISTURE LIBERATES METHANOL. INGESTION OF METHANOL MAYCAUSE BLINDNESS, NAUSEA, HEADACHE, VOMITING, GASTROINTESTINAL UPSET,DIZZINESS, IRREGULAR BREATHING, WEAKNESS, CONFUSION, DROWSINESS,UNCONSCIOUSNESS, AND DEATH.MATERIAL IS EXTREMELY DESTRUCTIVE TO TISSUE OF THE MUCOUS MEMBRANESAND UPPER RESPIRATORY TRACT, EYES AND SKIN.INHALATION MAY RESULT IN SPASM, INFLAMMATION AND EDEMA OF THELARYNX AND BRONCHI, CHEMICAL PNEUMONITIS AND PULMONARY EDEMA.SYMPTOMS OF EXPOSURE MAY INCLUDE BURNING SENSATION, COUGHING,WHEEZING, LARYNGITIS, SHORTNESS OF BREATH, HEADACHE, NAUSEA ANDVOMITING.TO THE BEST OF OUR KNOWLEDGE, THE CHEMICAL, PHYSICAL, ANDTOXICOLOGICAL PROPERTIES HAVE NOT BEEN THOROUGHLY INVESTIGATED.MAY BE HARMFUL IF ABSORBED THROUGH THE SKIN.CAN CAUSE BLINDNESS.

TOXIC IF INHALED.MAY BE HARMFUL IF SWALLOWED.CHRONIC EFFECTSTARGET ORGAN(S):EYESKIDNEYSLUNGSRTECS #: VV9800000SILICIC ACID, TETRAMETHYL ESTERTOXICITY DATAIPR-RAT LD50:100 MG/KG 85JCAE -,1222,1986IPR-MUS LD50:250 MG/KG CBCCT* 2,56,1950SKN-RBT LD50:17 ML/KG AMIHBC 4,119,1951ORL-MAM LD50:1 GM/KG GISAAA 39(4),86,1974TARGET ORGAN DATASENSE ORGANS AND SPECIAL SENSES (OTHER EYE EFFECTS)LUNGS, THORAX OR RESPIRATION (ACUTE PULMONARY EDEMA)KIDNEY, URETER, BLADDER (CHANGES IN TUBULES)MUSCULO-SKELETAL (OTHER CHANGES)ADDITIONAL INFORMATIONIHL-RAT LC50:0.4 MG/L/4HONLY SELECTED REGISTRY OF TOXIC EFFECTS OF CHEMICAL SUBSTANCES(RTECS) DATA IS PRESENTED HERE. SEE ACTUAL ENTRY IN RTECS FORCOMPLETE INFORMATION.SECTION 12. - - - - - - - - - ECOLOGICAL INFORMATION - - - - - - - - - -DATA NOT YET AVAILABLE.SECTION 13. - - - - - - - - - DISPOSAL CONSIDERATIONS - - - - - - - - -BURN IN A CHEMICAL INCINERATOR EQUIPPED WITH AN AFTERBURNER ANDSCRUBBER BUT EXERT EXTRA CARE IN IGNITING AS THIS MATERIAL IS HIGHLYFLAMMABLE.OBSERVE ALL FEDERAL, STATE AND LOCAL ENVIRONMENTAL REGULATIONS.SECTION 14. - - - - - - - - - - TRANSPORT INFORMATION - - - - - - - - -CONTACT FLUKA CHEMICAL COMPANY FOR TRANSPORTATION INFORMATION.SECTION 15. - - - - - - - - - REGULATORY INFORMATION - - - - - - - - - -EUROPEAN INFORMATIONFLAMMABLETOXICR 1FLAMMABLER 23TOXIC BY INHALATION.R 34

CAUSES BURNS.S 16KEEP AWAY FROM SOURCES OF IGNITION - NO SMOKING.S 45IN CASE OF ACCIDENT OR IF YOU FEEL UNWELL, SEEK MEDICAL ADVICEIMMEDIATELY (SHOW THE LABEL WHERE POSSIBLE).S 26IN CASE OF CONTACT WITH EYES, RINSE IMMEDIATELY WITH PLENTY OFWATER AND SEEK MEDICAL ADVICE.S 36/37/39WEAR SUITABLE PROTECTIVE CLOTHING, GLOVES AND EYE/FACEPROTECTION.REVIEWS, STANDARDS, AND REGULATIONSOEL=MAKACGIH TLV-TWA 1 PPM DTLVS* TLV/BEI,1999MSHA STANDARD:AIR-CL 5 PPM (30 MG/M3)DTLVS* 3,169,1971OSHA PEL (CONSTRUC):8H TWA 5 PPM (30 MG/M3)CFRGBR 29,1926.55,1994OSHA PEL (SHIPYARD):8H TWA 5 PPM (30 MG/M3)CFRGBR 29,1915.1000,1993OEL-AUSTRALIA: TWA 1 PPM (6 MG/M3), JAN1993OEL-BELGIUM: TWA 1 PPM (6 MG/M3), JAN1993OEL-DENMARK: TWA 1 PPM (6 MG/M3), JAN1999OEL-FINLAND: TWA 5 PPM (30 MG/M3), STEL 10 PPM (60 MG/M3), JAN1999OEL-FRANCE: VME 1 PPM (6 MG/M3), JAN1999OEL-JAPAN: OEL 1 PPM (6 MG/M3), JAN1999OEL-THE NETHERLANDS: MAC-TGG 1 PPM (6 MG/M3), JAN1999OEL-NORWAY: TWA 1 PPM (6 MG/M3), JAN1999OEL-SWITZERLAND: TWA 1 PPM (6 MG/M3), JAN1999OEL-UNITED KINGDOM: TWA 1 PPM (6.3 MG/M3), STEL 5 PPM (32 MG/M3),SEP2000OEL IN ARGENTINA, BULGARIA, COLOMBIA, JORDAN, KOREA CHECK ACGIH TLV;OEL IN NEW ZEALAND, SINGAPORE, VIETNAM CHECK ACGIH TLVNIOSH REL TO METHYL SILICATE-AIR:10H TWA 1 PPMNIOSH* DHHS #92-100,1992EPA TSCA SECTION 8(B) CHEMICAL INVENTORYEPA TSCA TEST SUBMISSION (TSCATS) DATA BASE, JANUARY 2001SECTION 16. - - - - - - - - - - OTHER INFORMATION- - - - - - - - - - - -THE ABOVE INFORMATION IS BELIEVED TO BE CORRECT BUT DOES NOT PURPORT TOBE ALL INCLUSIVE AND SHALL BE USED ONLY AS A GUIDE. SIGMA, ALDRICH,FLUKA SHALL NOT BE HELD LIABLE FOR ANY DAMAGE RESULTING FROM HANDLING

OR FROM CONTACT WITH THE ABOVE PRODUCT. SEE REVERSE SIDE OF INVOICE ORPACKING SLIP FOR ADDITIONAL TERMS AND CONDITIONS OF SALE.COPYRIGHT 2001 SIGMA-ALDRICH CO.LICENSE GRANTED TO MAKE UNLIMITED PAPER COPIES FOR INTERNAL USE ONLY.22. Procedures22.1 Shipping Equipment to Ellington FieldEquipment will be shipped assembled, tested, and working!! to Ellington field on April 10th, 2002,via UPS. Two packages will arrive, one containing the nested containment units, and one with miscellaneous other components.Gabe Hoffmann's team will be bringing our chemicals with them to JSC and leaving them thereuntil we arrive the next week. The chemicals will be accompanied by documentation.Equipment does not need any special storage requirements.22.2 Ground OperationsThe equipment will be set up and tested as it would be run on the KC. Reagent bags will be filledwith catalyst and molds will be filled with base. Molds will be placed into their drawers in the containment unit and tested.Access to a standard 120 VAC power source is required.22.3 LoadingThe containment units, without the molds in them, will be loaded onto a forklift to load it onto theKC. The boxes will be strapped to the floor with two straps. The glassware, molds, and computer will be brought on the planeseparately and installed.22.4 Pre-FlightThe computer will be boot, the program ZGel will be run, and the equipment will be tested.22.5 In-FlightPrior to each zero-gravity parabola, 5.0 mL of catalyst will be drawn. A mold will be taken out of itsdrawer and connected to the micro-t. In zero-g, the catalyst will be dispensed into the mold and a gel will be allowed to form.After 15 to 20 seconds, the gel will have formed and the mold will be put into a drawer.22.6 Post-FlightThe molds will be manually taken off the plane with the glassware and computer. New molds willbe loaded into the equipment and the glassware will be cleaned.22.7 OffloadingThe molds will be manually taken off the plane again, as well as the glassware and the computer.

The boxes will be taken off the plane by a forklift. The equipment will be shipped out of Ellington Field on April 25th, 2002 andsent back to Wisconsin by UPS.23. BibliographyAyers, M. How Silica Aerogels are Made. http://eande.lbl.gov/ECS/Aerogels/saprep.htm. (1998)Campbell, J. A. in Chemical Systems: Energetics, Dynamics, Structure. J. H. Freeman and Co. (1977)Hrubesh, Lawrence W.and Poco, John F.Processing and Characterization of High Porosity Aerogels. Lawrence Livermore National Laboratory Reports.(1994)Hunt, Arlon. Telephone Interview, 20 May 2001.Kong, Fung-Ming and Pekala, Richard W. A Synthetic Route to Organic Aerogels-- Mechanisms, Structure, and Properties. Lawrence Livermore National Laboratory Reports. (1988)Schaefer, Dale W. et al., "Origin of Porosity in Resorcinol-Formaldehyde Aerogels." Journal of Non-Crystalline Solids, 186, 159-167. (1995)Smith, David et al., "Effect of Microgravity on the Growth of Silica Nanostructures." Langmuir, 16, 10055-10060. (2000)Tillotson, T. M. and Hrubesh, L. Transparent Ultralow-density Silica Aerogels Prepared by a Two-Step Sol-Gel Process. Reports from Third International Symposium on Aerogels, Warzburg, Germany. (1991)Weast, Robert ed. Handbook of Chemistry & Physics, 48th Edition. Chemical Rubber Co. (1967)