Condensation polymerisation
| English | Chinese | Pinyin |
|---|---|---|
| condensation polymerisation | 缩合聚合 | suō hé jù hé |
| polyester | 聚酯 | jù zhǐ |
| polyamide | 聚酰胺 | jù xiān àn |
| diol | 二醇 | èr chún |
| dicarboxylic acid | 二羧酸 | èr suō suān |
Joining with loss
- In condensation polymerisation 缩合聚合, monomers join and a small molecule is lost each time.
- Each monomer needs two reactive groups, so the chain grows at both ends.
- The result is a polyester 聚酯 or a polyamide 聚酰胺.
Condensation polymer route
Watch monomers join while a small molecule leaves each time.
In condensation polymerisation:
Each new link releases a small molecule; the monomers need two reactive groups.
Polymers made by joining monomers with loss of a small molecule (e.g. water) form by ______ polymerisation.
Polyesters and polyamides form this way.
Polyesters and polyamides
- a polyester has many ester links. Make it from a diol 二醇 + a dicarboxylic acid 二羧酸 (or dioyl chloride), or from a single hydroxycarboxylic acid.
- a polyamide has many amide links. Make it from a diamine + a dicarboxylic acid, or from amino acids joining (proteins are natural polyamides).
Polyester and polyamide links form by losing a small molecule
A polyester can be made from:
A diol (two –OH) and a dicarboxylic acid (two –COOH) form ester links along the chain.
Proteins are examples of:
Amino acids join by amide (peptide) links, so proteins are polyamides.
Match each term to its meaning.
Each item links the term to its correct meaning.
Repeat units and monomers
- The repeat unit contains parts of both monomers, minus the small molecule lost.
- To find the monomers: break the chain at each ester/amide link, then add back –OH and –H (or –Cl).
Break the chain at each link and add back –OH and –H to recover the two monomers
PET drinks bottles are made of a polyester — a condensation polymer.
To find the monomers of a condensation polymer, you:
Breaking the links and restoring the lost atoms recreates the original monomers.
Condensation vs addition
- Condensation polymers lose a small molecule (water/HCl) at each link; addition polymers lose nothing.
- Polyesters and polyamides are condensation polymers.
You've got it
- condensation polymerisation: monomers join + a small molecule (e.g. water) is lost; each monomer has two groups
- polyester = ester links (diol + dicarboxylic acid); polyamide = amide links (diamine + dicarboxylic acid)
- proteins are natural polyamides; find monomers by breaking links and adding back –OH/–H