Synthetic polymers

Addition polymerisation

When polymers are made by linking together large number of smaller molecules

Requirements for poymerisation

• High pressures

• A catalyst

Difference between synthetic and natural polymers

Synthetic polymers are man-made (e.g. plastics, resins), while natural polymers are produced by nature (e.g. proteins, DNA)

Bond required for monomers to undergo addition polymerisation

A carbon-carbon double bond (C=C).

What happens to the C=C bond during polymerisation

One bond of the double bond breaks, forming single covalent bonds with adjacent monomers

4 Polymers in order

Poly(ethene), poly(propene), poly(chloroethene), poly(tetrafluoroethene)

Why is it hard do biodegrade addition polymers

The are inert and not easily broken down by microorganisms

What is the environmental problem with disposing of addition polymers in landfills

Addition polymers are non-biodegradable, so they cannot be decomposed by microorganisms, leading to landfills filling up quickly and wasting valuable land

What is a disadvantage of incinerating addition polymers

Incineration releases carbon dioxide, a greenhouse gas, and potentially toxic gases like hydrogen chloride (from chlorine-containing polymers) and carbon monoxide, which can harm the environment and human health

Condensation polymerisation

Two monomers are linked with the removal of a small molecule (usually water),

How are polyesters formed in condensation polymerisation

Polyesters are formed when a dicarboxylic acid (with -COOH groups) and a diol (with -OH groups) react, forming ester linkages and releasing water

Hydrolysis

The process of adding water to break down a polyester back into its original monomers.

Biopolyesters

Biopolyesters are biodegradable polymers made from sugars and plant oils using microorganisms, consisting of ester, amide, and ether functional groups