A polymer made by the combining together of small unsaturated molecules of the same compound.

Polymer formed by compounds which combine together by the rearrangement of chemical bonds. For example; polyethylene.

Addition polymers are made when monomers (simple molecules) add together across a double bond. Useful products from oil

An addition polymer is a polymer which is formed by an addition reaction, where many monomers bond together via rearrangement of bonds without the loss of any atom or molecule. This is in contrast to a condensation polymer which is formed by a condensation reaction where a molecule, usually water, is lost during the formation.