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Cellulose Nanofibers from Wheat StrawNDSU

Bernie SteeleOctober 12, 2007

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Cellulose Nanofibers Cellulose Nanofibers from Wheat Straw from Wheat Straw

for Highfor High--value Green value Green Nanocomposite Materials Nanocomposite Materials

ApplicationsApplications

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Outline

• Why cellulose nanofibers?

•Expected benefits

• Prior work

• Major tasks ahead

• State of the project and budget

• Summary

• Questions

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• Raw materials are abundant, cheap, and renewable

• Biodegradable

• High aspect ratio. Diameter: from 3 to 20 nmand lengths can reach up to a few micrometers

• Large surface area

• High modulus, high strength and low density

Why Cellulose Nanofibers (CNF)?

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Overall expected benefit:

“A composite that provides twice the mechanical stability with 1/3 less weight when compared to similar composites made using E glass fibers”

Cellulose Nanofibers (CNF)

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Cellulose Nanofibers (CNF)

Specific Fiber Density (g/cm3)

Tensile strength (GPa)

Young’s Modulus (GPa)

E glass fiber 2.54 - 2.62

~3.4 at 21 °C ~72.4 at 21 °C

Jute fiber 1.3 - 1.45 0.39 - 0.77 13 - 26 Cellulose

Nanofibers 1.5 ~10 ~150

[1] A .B. Strong,Fundamentals of Composites Manufacturing: Materials, Methods and Applications, Society of Manufacturing Engineers, 1989[2] A. K. Mohanty, M. Misra, and G. Hinrichsen, Macromolecular Materials and Engineering, 2000, 276/277, 1-24[3] A. Kelly and N. H. Macmillan, Strong Solids, 3rd edition, Oxford University Press, New York, 1986 [4] W. Helbert, J. Y. Cavaille, A. Dufresne, Polymer Composites, 1996, 17, 4, 604-611

• Improved tensile strength compared to jute fiber and E-glass fiber.

• Superior performance (Young’s, “stretch and break”) when compared to the jute and E glass fibers.

• 40% less density than E-glass fiber

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CNF From Wheat Straw

TEM micrograph showing the cellulose whiskers extracted from wheat straw (Scale 200 nm)

Cellulose nanowhiskers were successfully extracted from wheat straw using a combined chemical and mechanical extraction

Drzal, MSU Composite Materials and Structures Center

USDA-MBI Agreement 2006-34189-17124

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CNF Biocomposites from Wheat Straw

• Cellulose nanofiber/polyvinyl alcohol (PVOH) composite films were prepared by solution film casting. The films containing up to 5 wt% cellulose whiskers were transparent, indicating good dispersion of the fillers.

• The tensile modulus of the composite films was studied with Dynamic Mechanical Analyzer (DMA).

• The reinforcement effect of the cellulose nanofibers was more significant at high temperatures. – At 25°C, the reinforced films showed a slight increase in storage

moduli compared to the neat PVOH films.– At 80°C, there was a 36% increase in the storage moduli with

only 3wt% cellulose nanofibers • The modulus of polymer matrix drops to very low values

at high temperatures, which makes the high modulus of the cellulose whiskers more revealing

Drzal, MSU Composite Materials and Structures Center

USDA-MBI Agreement 2006-34189-17124

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CNF Biocomposites from Wheat Straw

Comparison of the storage moduli at 80 °C

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20

40

60

80

100

120

140

160

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Neat PVOH film 1wt% WS-CNW/PVOH

3wt% WS-CNW/PVOH

Stor

age

mod

ulus

(MPa

)

The comparison of the storage moduli of the PVOH films with and without cellulose nanowhiskers reinforcement

Drzal, MSU Composite Materials and Structures Center

USDA-MBI Agreement 2006-34189-17124

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MBI Biorefinery Concept

Wheat Straw

Milling AFEX EnzymeTreatment

EthanolFermentation

Cellulose NanofibersSizingChemical

Treatment

Xylitol

Succinic Acid

Butanetriol

Hemicellulose,Lignin By-Products

Free-Standing Cellulose Nanofibers Production ProcessIntegrated Cellulose Nanofibers Production Plant with an Ethanol Biorefinery Plant

tFermentation

Residue

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• Using current enzymes, not all wheat straw cellulose is hydrolyzed in enzymatic hydrolysis.

• The unhydrolyzed portion is likely the crystalline portion of the cellulose

MBI Concept

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Wheat Straw CNF

Cellulose nanofibers from wheat straw hydrolysate using an alkaline pulping process

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• Composites with CNF made from the alkaline pulping of fermentation residues have not been consistent enough for testing

• Further assay work on the hydrolysate and fermentation residues is needed to establish the mixture of compounds present with the CNF and whether these compounds may be causing the lack of success with casting the composite samples.

CNF Biocomposites from Wheat Straw

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Cellulose Nanofibers – Major Tasks

• Prepare and evaluate cellulose nanofiber samples from wheat straw hydrolysate and fermentation residues

• Analyze hydrolysate and fermentation residue samples to determine composition

• Prepare and evaluate composite materials reinforced with CNF

• Work toward a commercially viable technology package

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Cellulose Nanofiber Project

Demonstration of CNF from recycled paperDemonstration of CNF from corn stover & wheat strawDefinition of product specificationsEstablished preliminaryprocess economicsEvaluate integration withethanol plant

Project Costs = $500,000

Pre-Pilot process design and engineeringPreparation and evaluationof CNF samplesPreparation and evaluation of composite materialsRefine process definition,design, engineering and capital and operating costsPilot plant design andengineering

Project Costs = $1,000,000

Pilot plant constructionPreparation and evaluation of large scale CNF samplesPreparation and evaluation of large scale composite materialsRefine process definition, design, engineering and capital and operating costsValidation feedstock assumptionsand integration feasibility with an ethanol plant

Project Costs = $2,500,000

DetailedInvestigation

PreliminaryInvestigation Development Commercial

LaunchValidation

Ideas

4321 5

Business Partner: TBD

ProductConcept

ValueProposition

BusinessPlan

MarketingPlan

Michigan State UniversityMBI International

Tech/Com.Feasibility?

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Cellulose Nanofibers – Summary

• CNF can be found in wheat straw hydrolysate and fermentation residues

• CNF from wheat straw do reinforce PVOH films

• Alkaline pulping may be less expensive than acid pulping methods– Further work needed on this approach

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Acknowledgements

• Professor Larry Drzal and the staff at the Composite Materials and Structures Center, Michigan State University

•Darold McCalla, MBI

•Janette Moore, MBI

•Chris Saffron, MBI

•This work was supported in part by:

•USDA CSREES Grant No. 2006-34524-17132

•USDA CSREES Grant No. 2006-34189-17124

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Thank You!

Questions?