Problems with polymers

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.

Waste at landfill sites is eventually covered with soil
Waste at landfill sites is eventually covered with soil
Question

Describe what 'biodegradable' means.

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:

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.

Separating items at a recycling centre is just the first stage in sorting polymers
Separating items at a recycling centre is just the first stage in sorting polymers