Types of Polymers
Addition vs Condensation Polymers
| Addition | Condensation | |
|---|---|---|
| Monomer | Alkenes (C=C) | Diols + diacids, amino acids |
| By-product | None | Water (H₂O) |
| Examples | Polyethene, PVC, PTFE | Polyester, nylon, proteins |
| Atom economy | 100% | < 100% |
Structural Isomerism
Structural isomers have the same molecular formula but different structural formulas (different connectivity of atoms).
Example: C₄H₁₀
Butane
CH₃CH₂CH₂CH₃
Straight chain
Methylpropane
CH₃CH(CH₃)CH₃
Branched
Think About It
Why are condensation polymers typically biodegradable, but addition polymers are not?
Condensation polymers contain ester or amide linkages that can be hydrolysed (broken by water/enzymes). Addition polymers have only strong C−C bonds along the backbone, which are very resistant to chemical attack and biological degradation.