Polymer Chemistry - Lesson 9

Flashcards based on Polymer Chemistry Lecture Notes

What is Copolymerisation?

One of the cheaper polymer manufacturing methods to fulfill increasingly demanding market and more specific end-use requirements involving two or more distinct monomers.

What does EVA stand for?

Ethylene vinyl acetate copolymers

What does EVOH stand for?

Ethylene vinyl alcohol copolymer

Why is Polycarbonate/Acrylonitrile Butadiene Styrene (PC/ABS) a sought-after engineering thermoplastic?

It offers excellent impact and crack resistance and is widely used for automotive parts and aerospace components

How do monomers react in copolymerisation?

Monomers in copolymerisation will react chemically and form new copolymers.

What is a Polymer Blend?

A physical mixture of two or more different polymers

Name the types of copolymers

Random (-ran-), Alternating (-alt-), Block (-block-), Graft (-graft-), and Unspecified (-co-).

What is Poly (isoprene-ran-methyl methacrylate)?

A random copolymer with isoprene and methyl methacrylate as monomers.

What is Polypropylene-block-poly(vinyl chloride)?

Initiated by polypropylene followed by the chain extension of poly(vinyl chloride).

What property does Ethylene have?

It has good flexibility.

What does incorporating VAM monomers do?

It lowers the melting point which makes the manufacturing more energy-saving and it improves the flexibility; provides good crack and puncture resistance.

What properties does EVOH copolymer have?

It offers excellent gas barrier properties and good chemical resistance.

With the presence of alcohol groups (-OH), what is EVOH sensitive to?

It is sensitive to moisture and difficult to process.

Chain growth copolymerization employs active centers such as?

Free radicals, cations, and anions

In contrast to homopolymerisation, the composition of the monomers in the copolymerisation will vary towards other monomers and it will be affected by what?

Monomer reactivity ratios, temperature, pH, and viscosity.

What is the assumption of the terminal model?

The reactivity of a propagating radical depends solely on the identity of the last monomer unit added to the chain.

List the Factors that affect the monomer reactivity ratios

Steric effect of monomers, Resonance effect of monomer, Polar effect of the monomers, Temperature, Solvent used, Order of monomer addition

What is k11?

Rate constant for the propagation of a growing polymer chain with a terminal M₁ unit and reacting with M₁.

What is k12?

Rate constant for the propagation of a growing polymer chain with a terminal M₁ unit and reacting with M₂.

What is k22?

Rate constant for the propagation of a growing polymer chain with a terminal M₂ unit and reacting with M₂.

What is k21?

Rate constant for the propagation of a growing polymer chain with a terminal M₂ unit and reacting with M₁.

When r1r2 = 0 or r1 = r2 = 0 or ≈0, what type of copolymer is formed?

the monomer 1 tends to react with monomer 2, vice versa.

Calculate the values

Monomer 1 Monomer 2 r1 r2 r1r2 Ethylene Propylene 3.2 0.62 = 1.984, Vinyl acetate 0.79 1.4 = 1.106 ,Styrene Acrylonitrile 0.29 0.02 = 0.0058, Butadiene 0.82 1.38 = 1.1316, Maleic anhydride 0.097 0.001 = 0.000097, Methyl methacrylate 0.585 0.478 = 0.27963