Condensation Polymers – Quick Recap
- Condensation polymerization happens when monomers join together by eliminating small molecules (like water, HCl, or methanol).
- The process is stepwise, and the polymer grows gradually.
- These polymers usually come from monomers with two functional groups (like –COOH, –OH, –NH₂).
Examples of Condensation Polymers
1. Polyesters
- Formed by condensation of a dicarboxylic acid and a diol (alcohol).
- Example:
- Terylene (PET – Polyethylene terephthalate): From terephthalic acid + ethylene glycol.
- Uses: Clothing fibers, soft drink bottles, packaging films.
2. Polyamides
- Formed by condensation of a dicarboxylic acid (or diacid chloride) and a diamine.
- Examples:
- Nylon-6,6: From adipic acid + hexamethylenediamine.
- Nylon-6: From caprolactam (ring-opening polymerization).
- Kevlar: From terephthaloyl chloride + p-phenylenediamine.
- Uses: Textiles, ropes, bulletproof vests, carpets.
3. Phenol–Formaldehyde Resins
- From condensation of phenol and formaldehyde.
- Examples:
- Bakelite: A hard, thermosetting plastic.
- Uses: Electrical switches, kitchenware handles, adhesives.
4. Urea–Formaldehyde Resins
- From urea and formaldehyde.
- Uses: Adhesives, laminates, molded household items.
5. Melamine–Formaldehyde Resins
- From melamine and formaldehyde.
- Uses: Kitchenware, laminates, fire-resistant fabrics.
6. Polycarbonates (partly condensation type)
- Formed by condensation of bisphenol A and phosgene (COCl₂).
- Uses: CDs, lenses, bulletproof glass.
In short:
Some important condensation polymers are:
- Polyesters (Terylene, PET)
- Polyamides (Nylon, Kevlar)
- Phenol–formaldehyde resin (Bakelite)
- Urea–formaldehyde resin
- Melamine–formaldehyde resin
- Polycarbonates