Polyesters & Polyamides

What is a condensation polymer?

A polymer formed when monomers join together with the elimination of a small molecule, usually water

What type of molecule is removed during condensation polymerisation?

Water (H₂O)

Which two main types of condensation polymers are studied?

Polyesters and polyamides

What functional linkage is found in polyesters?

Ester linkage (–COO–)

How are polyesters formed?

By condensation between a dicarboxylic acid and a diol

What type of reaction forms polyesters?

Condensation reaction

What small molecule is released when forming a polyester?

Water

What is the name of the polymer formed from ethane-1,2-diol and benzene-1,4-dicarboxylic acid?

Terylene (PET)

Why are polyesters biodegradable?

They can be broken down by hydrolysis due to polar ester linkages

Why can water break down polyester chains?

Ester linkages are polar and react with water

What happens to polyesters in landfill over time?

They gradually hydrolyse and break down

What functional linkage is found in polyamides?

Amide linkage (–CONH–)

How are polyamides formed?

By condensation between a dicarboxylic acid and a diamine

What small molecule is released when forming a polyamide?

Water

What type of bond links monomers in a polyamide?

Amide bond

What is nylon-6,6?

A polyamide formed from hexanedioic acid and 1,6-diaminohexane

What monomers are used to make nylon-6,6?

Hexanedioic acid and 1,6-diaminohexane

What is Kevlar?

A strong polyamide polymer

What monomers are used to make Kevlar?

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

Why are polyamides strong materials?

They have strong intermolecular forces between amide groups

What process breaks down condensation polymers?

Hydrolysis

Which linkages can be broken by hydrolysis?

Ester and amide linkages

Why can ester and amide linkages be hydrolysed?

They are polar and react with water

What is ester hydrolysis?

The reverse of esterification

What products form when ester linkages are hydrolysed?

Alcohols and carboxylic acids

What happens when a polyester is hydrolysed?

It breaks back into a diol and a dicarboxylic acid

What conditions are used for acidic hydrolysis of esters?

Hot aqueous acid

What are the products of acidic ester hydrolysis in polymers?

Alcohols (or diols) and carboxylic acids

What conditions are used for alkaline hydrolysis of esters?

Hot aqueous alkali

What are the products of alkaline ester hydrolysis?

A carboxylate salt and an alcohol

Why does alkaline hydrolysis form a salt instead of an acid?

The carboxylic acid reacts further with the base

Can polyamides undergo hydrolysis?

Yes

What happens when polyamides are hydrolysed?

They break back into a diamine and a dicarboxylic acid

Do polyamides undergo both acid and base hydrolysis?

Yes