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Polymer SynthesisCHEM 421
Polymer Parameters
• Chemical structure– Chemical composition and distribution
– Sequence length and distribution
• Molecular weight and distribution
• Chain isomerism
• Morphology
• Topology
• Additives
• Cost
Polymer SynthesisCHEM 421
Amorphous Morphology
• - 80 °C
• - 20 °C
• 105 °C
• 290 °C
CH2 CH
n
CH2 CH
CH3n
CH2 CH2
n
CH2 C
n
CH3
Glass Transition Temperature
Polymer SynthesisCHEM 421
Structure-Property Relationships
CH3 CH2 OH
CH3 O CH3
CH3 CH2 CH3
4
CF3 CF2 CF3
4
Boiling Point
Boiling Point
• 46 g/mol
• 46 g/mol
Formula Weight
• 86 g/mol
• 188 g/mol
Formula Weight
Polymer SynthesisCHEM 421
Structure-Property Relationships
CH2 CH2
n
CF2 CF2
n
Tm (°C)
ΔG = ΔH — T ΔS
Polymer SynthesisCHEM 421
PE vs PTFE
Polymer SynthesisCHEM 421
Structure-Property Relationships
CH2 CH2
n
CH2 CH
nCH3
vs.
Tg (°C)
O CH2 CH2 O
n
vs.
C
O
C
O
O CH2 CH2 O
n
C
O
CH2CH2CH2CH2 C
O
Tm (°C)
Tm (°C)
Polymer SynthesisCHEM 421
Polymer Parameters
• Chemical structure– Chemical composition and distribution
– Sequence length and distribution
• Molecular weight and distribution
• Chain isomerism
• Morphology
• Topology
• Additives
• Cost
Polymer SynthesisCHEM 421
Topology
• Soluble and melt processable
–Linear
–Branched
» Long chain
» Short chain
Polymer SynthesisCHEM 421
Topology
Polymer SynthesisCHEM 421
Topology
• Network
– Insoluble
– Intractable» No flow with heat and
pressure
• aka
– Gel, cured, vulcanizate, thermoset, crosslinked
• Examples
– Rubber, epoxy glue, etc
Polymer SynthesisCHEM 421
Mechanical Properties
Polymer SynthesisCHEM 421
Effect of Branching on Melting Transitions of PEs
Polymer SynthesisCHEM 421
Polymer Parameters
• Chemical structure– Chemical composition and distribution
– Sequence length and distribution
• Molecular weight and distribution
• Chain isomerism
• Topology
• Morphology
• Additives
• Cost
Polymer SynthesisCHEM 421
Additives
C
C
O
O
O
O
CH2CH2CH2CH2CH2CH2CH2CH3
CH2CH2CH2CH2CH2CH2CH2CH3
• Plasticizers– PVC
» Tg ≈ 80 °C» Tg ≈ ? °C w/ 2% DOP
• Stabilizers– Processing temperature– Operating temperature– Properties
» MW» Brittleness» Discoloration» Cross-linking
CMe3Me3C
CH3
OH
Polymer SynthesisCHEM 421
Additives
• Anti-oxidants
• Flame retardants
• Colorants
• Dyes
• Fillers– Carbon black: UV screen, enhance modulus
– Fibrous reinforcers: glass, carbon, polymeric, ceramics
– Economic performance fillers: Saw dust, dirt, etc!
• Blowing agents
• Lubricants
Polymer SynthesisCHEM 421
Polymer Parameters
• Chemical structure– Chemical composition and distribution
– Sequence length and distribution
• Molecular weight and distribution
• Chain isomerism
• Topology
• Morphology
• Additives
• Cost
Polymer SynthesisCHEM 421
Cost
• Application dependent• Feedstock dependence
– Raw materials cost– Recycle vs new
• GDP independence?• Process improvements
– COO– Environmental issues– Catalysts– Automation/sensors
