Re: what name is given to the polymerisation reaction where water is added?

Hi Helen,

Thanks for the question. First, you are right about condensation polymerisation. This process is very common in biology, for instance when 2 amino acids join to form a peptide bond, with the elimination of water. Here's an example joining 2 glycine molecules.

2 H₂N-CH₂-COOH ---->H₂N-CH₂-CO- NH-CH₂-COOH + H₂O

The reverse of this process is hydrolysis, in which water is used to break a bond.

You ask about the 2 kinds of polymerisation and the kind where water is added. Off the top of my head I can't think of a polymerisation where water is added, but the second type of polymerisation is called addition polymerisation. In this process a molecule is activated, then added to the growing chain, but nothing is eliminated. If you look at this link: http: //www- class.unl.edu/chem/HTML/lecture_syllabus/polymers/polymerization.htm

you can see this process during Latex production (unfortunately their animation doesn't seem to be working).

I hope this helps your question. If you have other general chemistry questions, 2 good resources are General Chemistry Online, at http://anto ine.frostburg.edu/chem/senese/101/index.shtml and the AboutCom chemistry pages at http://chemistry.about .com/science/chemistry/

Neil Saunders