polymer synthesis chem 421 polymer parameters chemical structure –chemical composition and...

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