During condensation polymerisation, what else forms other than the polymer?

In condensation polymerization, two or more monomers join together to form a polymer, and in the process, they typically release a small molecule as a byproduct. This is a key characteristic of condensation reactions. Common byproducts include water (H₂O) or hydrogen chloride (HCl), depending on the nature of the monomers involved.

For instance, when an amine reacts with a carboxylic acid to form a polyamide, water is liberated during the formation of the amide bond. This release of a small molecule is vital to the definition of condensation polymerization, distinguishing it from addition polymerization, where no such byproduct is formed. Thus, the formation of a small molecule like H₂O or HCl is a fundamental part of the process and is accurate in describing what occurs alongside the production of the polymer itself.