Polymers

Polymers are made by chemical reactions that join lots of small molecules together to make long molecules. For example, a molecule of poly(ethene) is made by joining thousands of ethene molecules together. Long molecules like these give polymers their properties.

Ethene molecules make long polyethene molecules.Ethene molecules join together to make long molecules of poly(ethene)

Polymer properties

Polymers often have these properties in common. They are:

  • chemically unreactive
  • solids at room temperature
  • plastic – they can be moulded into shape
  • electrical insulators
  • strong and hard-wearing

The table shows some polymers, their typical uses and the properties that make them suitable for these uses:

Polymer nameTypical useProperties
Poly(ethene) or polythenePlastic bagsStrong and hard-wearing
PVCWater pipesStrong, hard-wearing, chemically unreactive
PVCOuter layer of electric wiresElectrical insulator, hard-wearing
NylonClothingCan be made into fibres, strong and flexible
LycraSports clothingCan be made into fibres, very elastic and tough
Electrical socket
Some polymers are hard and rigid, like the polymer used to make this electrical socket

Polymer problems

Polymers are usually chemically unreactive. This is a useful property because it means that plastic bottles will not react with their contents. Unfortunately, it makes polymers difficult to dispose of. They do not rot away very quickly and they can cause litter problems.