Chemistry- Polymers

Teflon Natural rubber Neoprene Polystyrene

Heavily branched cross linked polymers, Linear slightly branched long chain molecules. Become infusible on moulding so cannot be reused. Soften on heating and harden on cooling, can be reused.

Dacron Buna-S Neoprene Novolac

Tough ✘ Hard ✘ Poor conductor of electricity ✘ Highly branched structure ✔

Amide ✘ Ester ✘ Diene ✘ Nitrile ✔

High water absorption, resistant to oxidation and good elasticity ✘ High water absorption, susceptible to oxidation and no elasticity ✘ High water absorption, susceptible to oxidation and good elasticity ✘ Low water absorption, resistance to oxidation and good elasticity. ✔

Teflon ✘ Glyptal ✘ Nylon-6 ✘ Buna-S ✔

Terylene ✘ Polyethylene ✘ Polypropylene ✘ Nylon-6 ✔

Phenol and formaldehyde ✘ Urea and formaldehyde ✘ Adipic acid and hexamethylene diamine ✘ Ethylene glycol and pthalic acid ✔

Cellulose ✘ Polyethene ✘ PVC ✘ Nylon-6 ✔