Condensation Polymerisation

Condensation polymerisation occurs when two different molecules react, and a water molecule is eliminated.
So water is a by-product.
Hence the term "condensation".

Since water has to be eliminated, the monomers themselves must have hydroxyl OH and carboxylic groups .i.e. OH and COOH groups from which the H2O can be eliminated.

So alcohols (with 2 -OH groups) and carboxylic acids (with 2 -COOH groups))are used.

This condensation polymerisation reaction will use an alcohol and an acid, which will create an ester.
Hence this polymer is called a polyester.


Example of alcohol used
a diol (alcohol with 2 OH groups)
Name: ethan-1,2-diol



Example of acid used
a dicarboxylic acid (acid with two COOH groups)
Name: dipropanoic acid




Step 1
The H from the alcohol combines with the OH from the acid, and water is produced (eliminated from the organic system of molecules)




Step 2
The alcohol and acid then join at that point.




Step 3
Notice that the alcohol and acid are repeating in the molecule.




Step 4
The polymer, which is a polyester.


polyester

Water would be the by-product.






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