Predicting the type of polymerisation
Predicting the type of polymerisation
- There are two kinds of polymerisation.
- A couple of clues tell them apart.
- It comes down to the monomer and what (if anything) is lost.
The clues
| Clue | Type |
|---|---|
| monomer has a C=C and nothing is lost | addition polymerisation |
| each monomer has two functional groups, a small molecule is lost, the chain has ester/amide links | condensation polymerisation |
Practice
A monomer with a C=C double bond, where nothing else is lost, undergoes:
Addition polymerisation opens the C=C and joins monomers with no other product.
Practice
Monomers with two functional groups that lose a small molecule give:
Two-group monomers join with loss of a small molecule, forming ester/amide links — condensation.
Practice
A polymer chain that contains ester or amide links was made by:
Ester/amide links are the signature of condensation polymers (addition polymers have a plain C–C backbone).
You've got it
Key idea
- addition: a C=C monomer opens up, nothing else is lost
- condensation: two-group monomers join, a small molecule is lost, leaving ester/amide links