Key words

Polymer A very large molecule formed from many monomer molecules
Monomer Small molecules that join together to form one large polymer molecule
Addition polymerisation A reaction where the C=C double bonds of a monomer are split up to form a larger molecule
Condensation polymerisation A reaction where the polymer forms when a molecule of water is lost in order to join the two monomers.
Macromolecule A very large molecule made up of repeating units of atoms or molecules

Addition polymerisation

Alkenes can take part in addition reactions.

Formation of an addition polymer

  1. The carbon-carbon double bond changes to a single bond.
  2. They join with other alkenes whose double bonds have broken to a single bond.
  3. They form an addition polymer.

How to deduce the structure of a monomer from an addition polymer

  1. Draw the structure of a single repeating unit from the polymer
  2. Add a double bond between the carbon atoms.
  3. Remove the two lines at from each side

How to deduce the structure of an addition polymer from a monomer

  1. Reduce the double bond to single bond (like that of an alkane)
  2. Add two single bonds at each end of the monomer.
  3. Add two brackets on both sides (make sure the brackets cut the line you drew in step 2.)
  4. Add an ’n’ to the bottom right corner of the diagram (outside the brackets)