Chemistry - 3.3.12: Polymers

3 examples of condensation reactions that form polymers

1. Dicarboxylic acids and diols

2. Dicarboxylic acids and diamines

3. Amino acids

Give an example of a polyester

Terylene

Give 2 examples of polyamides

Nylon 6,6 and Kevlar

Condensation reaction

A reaction where two molecules react together and a small molecule is eliminated

Give 2 examples of condensation polymers

Polyesters and polyamides

What linkage is in polyesters?

The ester linkage, -COO-

How do you make a polyester?

Condensation reaction between diols and dicarboxylic acids

Draw the structure of Terylene

What linkage is in polyamides?

-CONH-

How do you make a polyamide?

Condensation reaction between diamines and dicarboxylic acids OR between amino acids

Draw the structure of Nylon 6,6

Draw the structure of Kevlar

Why is Kevlar strong? (2)

Its rigid chains + the planar aromatic rings, which can pack together and are held by strong intermolecular forces

Are addition polymers biodegradeable and why?

No - they are chemically inert since they only have strong, non-polar C-C and C-H bonds

How are addition polymers disposed of? (3)

In landfills, by incineration or by being melted down and remoulded (recycling)

Are polyesters and polyamides biodegradable?

Yes - they can be broken down by hydrolysis reactions

Advantages and disadvantages of recycling (2v1)

ADVANTAGES:

1. Preserves non-renewable resources

2. Prevents them from filling landfill sites

DISADVANTAGES:

1. Plastics need to be collected, transported and sorted - time-consuming, expensive

Condensation polymer hydrolysis (reagent + conditions)

Concentrated aqueous NaOH + Heat under reflux

Why are condensation polymers biodegradable but not addition polymers? (2)

1. Condensation polymers have polar bonds (C=O), while addition polymers have non-polar bonds

2. This means that condensation polymers can be attacked by nucleophiles and/or hydrolysed

Which of the polymers that need to be memorised have hydrogen bonding between the polymer chains?

Kevlar

Nylon 6,6 monomers

Hexane-1,6-diamine and butanedioic acid

Hydrolysis reaction

A reaction with water used to break down a compound

Kevlar monomers

1,4-diaminobenzene and benzene-1,4-dicarboxylic acid

What is Kevlar used for? (2)

Bullet-proof clothing