Polymers

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  • Created by: Abbie
  • Created on: 21-02-11 22:07

Polymers

Polymerisation - This is the process of making long chains of plastic (polymer) molecules from lots of single unit alkene molecules (monomers).

For example, many ethene molecules can be joined together to make polyethene or 'polythene'.

An ethene monomer has four hydrogen atoms and two carbon atoms that are joined together with a double bond. After polymerisation, the monomer forms a repeating unit of polyethene which has single bonds between the carbon atoms. A chloroethene monomer has three hydrogen atoms, one chlorine atom and two carbon atoms. The carbon atoms are joined together with a double bond. After polymerisation, the monomer forms a repeating unit of polychloroethene that has single bonds between the carbon atoms (http://www.bbc.co.uk/schools/gcsebitesize/science/images/gcsechem_29.gif)

The physical properties of a polymer depends on what it's made of and the temperature and pressure of polymerisation.

For example, polyethene is made at 200oC and 2000 atmospheres pressure and it's flexible with a low density. But polyethene made at 60oC and a few atmospheres pressure with a catalyst is…

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