3.4.9 Polymers - Condensation polymers
Students should:
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Condensation
This is otherwise known as addition - elimination, in other words a reaction that starts with addition of one molecule to another, followed by elimination of a small molecule, such as water, ammonia or a hydrogen halide.
Condensation reactions occur:
With amines
- Amines and acid chlorides
- Amines and acid anhydrides
- Amines and carboxylic acids
These all form amide (peptide) linkages between the two original molecular units
With alcohols
- Alcohols and acid chlorides
- Alcohols and acid anhydrides
- Alcohols and carboxylic acids
These all produce ester linkages between the original molecular units.
Condensation polymerisation
This can occur when each of the reacting molecules has two functional groups able to condense.
For example:
A diamine (A) and a dioyl chloride (B)
The molecules can then link together in a chain A-B-A-B-A-B- etc