Different polymers have different properties. This means that different polymers have different uses.
The table gives examples of polymers, their common names, and their typical properties and uses.
| Polymer | Properties | Uses |
| Poly(ethene) ‘polythene’ | Flexible, cheap, can be made into thin films | Carrier bags, shampoo bottles, food wrap |
| Poly(propene) ‘polypropylene’ | Flexible, strong, resists shattering | Buckets, bowls, crates, ropes, carpets |
| Poly(chloroethene) ‘PVC’ | Tough, electrical insulator, can be made hard or flexible | Insulation for electrical wires, windows, gutters, pipes |
| Poly(tetrafluoroethene) ‘PFTE’ | Slippery, chemically unreactive | Non-stick coatings for pans, containers for laboratory substances |
One of the useful properties of polymers is that they are unreactive. This means they are suitable for storing food and other substances safely. Unfortunately, this property makes it difficult to dispose of polymers.
Not biodegradable
Most polymers, including poly(ethene) and poly(propene) are not biodegradable. This means that microorganisms cannot break them down, so they:
- cause a litter problem if disposed of carelessly
- last for many years in landfill sites
Suitable places for landfill sites are difficult to find. Space in landfill sites is wasted if it is filled with non-biodegradable polymers.
Question
Describe what ‘biodegradable’ means.
answer
If something is biodegradable, it can be broken down or decomposed by microorganisms.
Combustion
Waste polymers can be incinerated. This involves combustion at very high temperatures. Incineration releases a lot of energy which can be used to heat homes or to generate electricity.
There are problems with incineration:
- carbon dioxide is produced, a greenhouse gas which contributes to global warming
- toxic gases are produced which need removing before they leave the chimney
Recycling
The use of landfill and incineration wastes valuable resources. Crude oil is the raw material for making most polymers, and it is a finite resource. Recycling reduces the problems of disposal, and also reduces the volume of crude oil used.
Recycling involves:
- melting the waste polymer
- forming the polymer into a new product
However, different polymers must be separated from each other first. This can be difficult and expensive to do.
