Chemistry – Organic chemistry - Polymers | e-Consult
Organic chemistry - Polymers (1 questions)
The key difference between addition and condensation polymerisation lies in the monomers involved and the byproducts formed.
Addition Polymerisation: Monomers with unsaturated bonds (double or triple bonds) add directly to each other to form a polymer. No small molecules are lost. A catalyst is typically required to speed up the reaction.
Example: Poly(ethene) (polythene) is made by the addition polymerisation of ethene.
Condensation Polymerisation: Monomers react with each other, and a small molecule (e.g., water, hydrogen chloride) is lost as a byproduct. This means fewer monomers are needed to make a polymer of a given molar mass.
Example: Polyester (e.g., Polyethylene terephthalate - PET) is made by the condensation polymerisation of a diol and a dicarboxylic acid, with water as a byproduct. Polyamide (e.g., Nylon) is another example, formed from a diamine and a dicarboxylic acid, with water as a byproduct.
| Addition Polymerisation | Condensation Polymerisation |
| Monomers: Unsaturated (double/triple bonds) | Monomers: Often containing functional groups (e.g., -OH, -COOH) |
| Byproduct: None | Small molecule (e.g., water) |
| Catalyst: Usually required | Not usually required |
| Example: Poly(ethene) | Example: Polyester, Polyamide |