2.4.6 Condensation
HL OnlyPolymers formed with the release of a small molecule.
The Mechanism
Unlike addition polymerization, condensation requires monomers with two functional groups. A reaction occurs between these group ends, linking the monomers and releasing a small molecule (usually or ) for every link formed.
Atom Economy: < 100% (due to loss of small molecule).
Key Polymer Types
| Type | Reactants | Linkage | Example |
|---|---|---|---|
| Polyester | Dicarboxylic Acid + Diol | Ester () | PET (Terylene) |
| Polyamide | Dicarboxylic Acid + Diamine | Amide () | Nylon, Kevlar |
Biodegradability
Addition Polymers
Contain a strong, non-polar C-C backbone. They are chemically inert and therefore non-biodegradable.
Condensation Polymers
Contain polar linkages (Ester/Amide). These bonds are susceptible to hydrolysis (breakdown by water) in acidic or alkaline conditions, making them biodegradable.