Polymers

How are condensation polymers formed

Formed from the removal of water molecules

What monomers form polyamides, polyesters, polypeptides

Dicarboxylic acids + diols → polyester (ester linkages)

Dicarboxylic acids + diamines → polyamides (amide links)

Multiple amino acids→ presence of both NH and OH forms (-CONH- peptide links)

How are polymers broken down?

Condensation polymerisation can be reversed by hydrolysis- addition of water to break links

• hydrolysis with water too slow → acid/ base

How are polyamides broken down

Polyamides hydrolyse more easily with an acid than a base

Polyamide + water + acid → dicarboxylic acid + diamine

How are polyesters broken down

Polyesters hydrolyse more easily with a base to form a salt of the carboxylic acid

Polyester + base → dicarboxylic acid salt + diol

Why are polymers formed from condensation stronger than polymers formed from addition reactions

• H-bonding + dipole dipole forces present in condensation polymers

• Addition polymers only have VDW forces

Some uses of condensation polymers

• bulletproof vests

• Heat protective materials

How are addition polymers disposed of

Addition polymers are very inert + non-polar bonds so not easily broken down → non-biodegradable

• Saves money on transport, can be incinerated locally

• Prevents unsightly landfill sites

• Green house gases released +CO + SO2 (acid rain)

• Still produces waste

• More expensive than landfill

How are condensation polymers disposed of And what are advantages and disadvantages of that method

Hydrolysis due to polarity → biodegradable

landfill so they gradually break down

• cost-effective

• Wastes land

• Leach compounds into the soil

• Eyesores

• Release methane (greenhouse gas)