Addition polymerisation

Addition polymerisation is a process in which monomers join together to form polymers without producing by-products. In contrast to condensation polymerisation, in which by-products such as water, alcohol or other small molecules are split off, addition polymerisation involves a direct linking of the monomers through the formation of covalent bonds.

Typically, addition polymerisation proceeds in a chain reaction in which the monomers are added step by step to a growing polymer chain. This occurs through the reaction of the double or triple bonds in the monomer, creating new single bonds.

A well-known example of addition polymerisation is the polymerisation of ethylene to polyethylene, in which the double bond in the ethylene molecule is broken in order to form a long chain of ethylene molecules that are linked to one another by single bonds.