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8/6/2019 Lec#3 Polymers I-2
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PolymersPolymersPolymerization, PolymerPolymerization, Polymer
Structure, MorphologyStructure, Morphology
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Objectives
1. Explain the basic steps in polymerization.
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Objectives
1. Explain the basic steps in polymerization.
2. Explain the epoxy/amine reaction mechanism.
8/6/2019 Lec#3 Polymers I-2
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Objectives
1. Explain the basic steps in polymerization.
2. Explain the epoxy/amine reaction mechanism.
3. Identify the grafting/copolymer structures and/or name them.
8/6/2019 Lec#3 Polymers I-2
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Objectives
1. Explain the basic steps in polymerization.
2. Explain the epoxy/amine reaction mechanism.
3. Identify the grafting/copolymer structures and/or name them.
4. Identify or sketch the various isomeric structures possible with a vinyl polymer.
8/6/2019 Lec#3 Polymers I-2
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Objectives
1. Explain the basic steps in polymerization.2. Explain the epoxy/amine reaction mechanism.
3. Sketch/identify the four basic vinyl molecules4. Identify the grafting/copolymer structures and/or
name them.5. Identify or sketch the various isomeric structures
possible with a vinyl polymer.6. Explain the basis for polymer crystallinity.
8/6/2019 Lec#3 Polymers I-2
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Polymer Building BlocksPolymer Building Blocks
H ydrogenH ydrogenCarbon (key)Carbon (key)
OxygenOxygenNitrogenNitrogenFluorineFluorineSiliconSiliconSulfurSulfurChlorineChlorine
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Polymerization ProcessesPolymerization Processes
A ddition PolymerizationA ddition PolymerizationNo ByproductsNo Byproducts
Usually heat drivenUsually heat driven
Condensation PolymerizationCondensation PolymerizationByproducts producedByproducts producedRemoval of byproduct controls rateRemoval of byproduct controls rate
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L inear A dditionL inear A ddition
Begin with ethylene (gas)Begin with ethylene (gas)Monomer or ³mer´ Monomer or ³mer´ Each bond is a sharedEach bond is a sharedelectron pair.electron pair.
A polymer is formed byA polymer is formed bycatalyzing the formation of catalyzing the formation of a free radical:a free radical:
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A ddition Polymerization
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C ondensation ReactionC ondensation Reaction
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Eff ects o f Polymerization SchemeEff ects o f Polymerization Scheme
Polymer may contain residualPolymer may contain residualbyproduct.byproduct.
A ddition polymerization done inA ddition polymerization done insolvent may have residual solventsolvent may have residual solventCleanest polymers are gas phase orCleanest polymers are gas phase oraqueous solution polymersaqueous solution polymers
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Basic Steps in PolymerizationBasic Steps in Polymerization
Initiation:Initiation: Formation of Formation of free radicalfree radical
Propagation:Propagation: Combining of Combining of mers to formmers to formchainschains
Termination:Termination: Elimination of Elimination of free radicalsfree radicals
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Polymerization Step Eff ectsPolymerization Step Eff ects
The actual method of initiation,The actual method of initiation,propagation, termination will affectpropagation, termination will affectfinal properties.final properties.
You cannot easily switch suppliers orYou cannot easily switch suppliers orresin once a particular material andresin once a particular material andfactory have been qualified.factory have been qualified.
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PropertiesProperties
Behavior determined by aBehavior determined by acombination of primary backbonecombination of primary backbonebonds and secondary bonds.bonds and secondary bonds.
Different monomers will haveDifferent monomers will havedifferent secondary bond strengths.different secondary bond strengths.
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L evels o f Polymer ArchitectureL evels o f Polymer Architecture
Monomer TypeMonomer Type
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Families based on an ethenic backbone areFamilies based on an ethenic backbone arevinylvinyl polymers or vinylydinespolymers or vinylydines
PolyethylenePolyethylenePEPE
PolypropylenePolypropylenePPPP
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PolystyrenePolystyrenePSPS
PolyvinylchloridePolyvinylchloridePVCPVC
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L evels o f Polymer ArchitectureL evels o f Polymer Architecture
Monomer TypeMonomer TypeMolecule L engthMolecule L ength
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Molecular Weight:Molecular Weight:
Number AverageNumber Average
Weight AverageWeight Average
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L evels o f Polymer ArchitectureL evels o f Polymer Architecture
Monomer TypeMonomer TypeMolecule L engthMolecule L ength ± ± molecular weightmolecular weight
Mixture of MonomersMixture of Monomers - - copolymerscopolymers
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Types o
f C
opolymersT
ypes of C
opolymersH omopolymerH omopolymer AAAAAAAAAAAAAAAAAAAAAA
RandomRandom CC A CBB A CA BAACCA CBB A CA BAA
A lternatingA lternating A BCA BCA BCA BCA BCA BCA BCA BCBlockBlock AAAA BBBBCCCCAAAA BBBBCCCCGraftGraft
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L evels o f Polymer ArchitectureL evels o f Polymer Architecture
Monomer TypeMonomer TypeMolecule L engthMolecule L ength ± ± molecular weightmolecular weight
Mixture of MonomersMixture of Monomers ± ± copolymerscopolymersMonomer A rrangementMonomer A rrangement - - IsomersIsomers
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Isomerism/Polymer TacticityIsomerism/Polymer Tacticity
IsotacticIsotactic
SindiotacticSindiotactic
RandomRandom
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L evels o f Polymer ArchitectureL evels o f Polymer Architecture
Monomer TypeMonomer TypeMolecule L engthMolecule L ength ± ± molecular weightmolecular weight
Mixture of MonomersMixture of Monomers ± ± copolymerscopolymersMonomer A rrangementMonomer A rrangement ± ± IsomersIsomersBond/Network StructureBond/Network Structure
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Polymer CategoriesThermoplastic ± only secondary bonds between
molecules.-´Plastic´ or reshapable- Melted and formed under pressure
- Higher tooling costs
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Polymer CategoriesThermoplastic ± only secondary bonds between
molecules.-´Plastic´ or reshapable- Melted and formed under pressure
- Higher tooling costs
Thermoset ± primary and secondary bonds betweenmolecule segments.
- Cannot be reshaped- Low viscosity in processing- Cheaper tooling
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Thermoset
Frequent Cross-links Create 3-D Network
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A morphous Polymer ± Lightly Crosslinked
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Semicrystalline Thermoplastic
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L evels o f Polymer ArchitectureL evels o f Polymer Architecture
Monomer TypeMonomer TypeMolecule L engthMolecule L ength ± ± molecular weightmolecular weight
Mixture of MonomersMixture of Monomers ± ± copolymerscopolymersMonomer A rrangementMonomer A rrangement ± ± IsomersIsomersBond/Network StructureBond/Network Structure
Molecular ConformationMolecular Conformation
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A morphousA morphous
Example:Example:
PolycarbonatePolycarbonate
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Crystalline
Example: Polyethylene
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CrystalsCrystals
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L evels o f Polymer ArchitectureL evels o f Polymer Architecture
Monomer TypeMonomer TypeMolecule L engthMolecule L ength ± ± molecular weightmolecular weight
Mixture of MonomersMixture of Monomers ± ± copolymerscopolymersMonomer A rrangementMonomer A rrangement ± ± IsomersIsomersBond/Network StructureBond/Network Structure
Molecular ConformationMolecular ConformationBlends/ A lloysBlends/ A lloys
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L evels o f Polymer ArchitectureL evels o f Polymer Architecture
Monomer TypeMonomer TypeMolecule L engthMolecule L ength ± ± molecular weightmolecular weightMixture of MonomersMixture of Monomers ± ± copolymerscopolymersMonomer A rrangementMonomer A rrangement ± ± IsomersIsomersBond/Network StructureBond/Network StructureMolecular ConformationMolecular ConformationBlends/ A lloysBlends/ A lloysA dditivesA dditives
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Polymer C ategories: NetworkPolymer C ategories: Network
ThermosetThermoset vs vs ThermoplasticThermoplastic
NetworkNetwork vsvs L inearL inear
FixedFixed vsvs ReshapeableReshapeable
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Polymer C ategories: ApplicationPolymer C ategories: ApplicationPlasticsPlasticsA dhesivesA dhesivesFilmsFilmsFibersFibersElastomersElastomers
