Q.What is Condensation Polymer ? Give two examples.

Condensation polymers are built up by successive condensation reactions between two different multifunctional monomers, each step releasing a small molecule such as water — nylon-6,6 (from a diamine and a diacid) and terylene (from a diol and a diacid) are the classic textbook examples.

A condensation polymer is formed by repeated condensation reactions between two different bifunctional (or polyfunctional) monomer molecules, in which each successive step involves the elimination of a small molecule such as water, an alcohol, ammonia, or hydrogen chloride. Because a small molecule is lost at each linking step, the molecular formula of the repeating unit in the polymer is not simply the sum of the monomer formulae (unlike addition polymers).

Example 1 — Nylon-6,6: formed by the condensation polymerisation of hexamethylenediamine and adipic acid, with loss of water at each amide-bond-forming step: $n\,H_2N(CH_2)_6NH_2 + n\,HOOC(CH_2)_4COOH \rightarrow [-NH(CH_2)_6NHCO(CH_2)_4CO-]_n + 2n\,H_2O$

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