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Addition polymerization



Addition polymerisation, also called polyaddition or chain growth polymerization, is a polymerisation technique where unsaturated monomer molecules add on to a growing polymer chain one at a time. It can be represented with the chemical equation:
nM (monomer) --> -(-M-)n- (polymer)

Characteristics

The main characteristics are:

  • polymerisation process takes place in three distinct steps:
  1. chain initiation, usually by means of an initiator which starts the chemical process. Typical initiators include any organic compound with a labile group: e.g. azo (-N=N-), disulphide (-S-S-), or peroxide (-O-O-). Two examples are benzoyl peroxide and AIBN.
  2. chain propagation
  3. chain termination, which occurs either by combination or disproportionation. Termination, in radical polymerisation, is when the free radicals combine and is the end of the polymerisation process.
  • some side reactions may occur, such as: chain transfer to monomer, chain transfer to solvent, and chain transfer to polymer.

Examples

 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Addition_polymerization". A list of authors is available in Wikipedia.
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