Condensation polymerisation is a process used to form polymers, but unlike addition polymerisation, it involves monomers with different functional groups. This type of polymerisation typically occurs between a di-alcohol (a molecule with two alcohol functional groups) and a di-acid (a molecule with two carboxylic acid functional groups).

How It Works: Monomers with Different Functional Groups: In condensation polymerisation, the monomers each have different functional groups, such as an alcohol group (-OH) and a carboxylic acid group (-COOH).

Formation of Polymer Chain: When these monomers react, they form a large polymer chain. For each new bond formed between the monomers, a small molecule, usually water, is also produced.