Editing Condensation polymer (section)

==Polyamides==
One important class of condensation polymers are [[polyamide]]s.<ref>{{cite encyclopedia |author=B. Herzog |author2=M. I. Kohan |author3=S. A. Mestemacher |author4=R. U. Pagilagan |author5=K. Redmond|title=Polyamides|encyclopedia=Ullmann's Encyclopedia of Industrial Chemistry|year=2013|publisher=Wiley-VCH|place=Weinheim|doi=10.1002/14356007.a21_179.pub3|isbn=978-3-527-30673-2 |s2cid=241272519 }}</ref> They arise from the reaction of [[carboxylic acid]] and an amine.  Examples include [[nylon]]s and [[protein]]s. When prepared from amino-carboxylic acids, e.g. amino acids, the stoichiometry of the polymerization includes co-formation of water:
:n H<sub>2</sub>N-X-CO<sub>2</sub>H  →  [HN-X-C(O)]<sub>n</sub>  +  (n-1) H<sub>2</sub>O

When prepared from [[diamine]]s and [[dicarboxylic acid]]s, e.g. the production of [[nylon 66]], the polymerization produces two molecules of water per repeat unit:
:n H<sub>2</sub>N-X-NH<sub>2</sub> + n HO<sub>2</sub>C-Y-CO<sub>2</sub>H  →  [HN-X-NHC(O)-Y-C(O)]<sub>n</sub>  +  (2n-1) H<sub>2</sub>O
:[[Image:Condensation polymerization diacid diamine.svg|thumb|left|400px|General chemical structure of one type of condensation polymer]]{{clear}}