4:48 (Triple only) know that condensation polymerisation, in which a dicarboxylic acid reacts with a diol, produces a polyester and water

Condensation polymers are formed by a condensation reaction.

These polymers are formed by the combination of two different monomers, such as a dicarboxylic acid and a diol.

When these particular monomers join in an alternating pattern they form a long polymer called a polyester. Where each monomer joins to the next, a separate molecule of water is also produced.