Open Book Paper
Addition polymerisation is the reaction that forms many of the polymers (a long molecule made up from lots of small molecules called monomers). Usually there is a C=C double bond as there is in alkenes. Addition polymers were found by accident and are know as A-A polymers because all the monomer molecules are the same.
Polymerisation is a three-stage process. Below shows the polymerisation of ethane to low density poly(ethene) (ldpe)
Stage 1 : INITIATION This is when there is a creation of a radical from a catalyst
Stage 2 : PROPAGATION A radical now combines with one of the electrons from the double bond in the alkene:
New radical then reacts with more alkene: