Polymers and Chemistry in Everyday Life
Polymers and Chemistry in Everyday Life covers polymer classification, important commercial polymers, biodegradable polymers, drugs and food additives. Learn monomers and linkage types.
Polymer types
Addition polymers form without elimination: polyethylene, PVC, polypropylene, polystyrene and Teflon. Condensation polymers eliminate a small molecule: nylon-6,6 from adipic acid and hexamethylenediamine (amide linkage), terylene from terephthalic acid and ethylene glycol (ester linkage), and bakelite from phenol and formaldehyde. Natural rubber is cis-polyisoprene; vulcanisation with sulfur creates cross-links. Buna-S is a copolymer of butadiene and styrene.
Everyday chemistry
Analgesics relieve pain; antibiotics treat infection; antacids neutralise stomach acid; antihistamines block histamine. Food preservatives include sodium benzoate and salts of propanoic acid. Soaps are salts of fatty acids and form micelles; detergents work in hard water because their calcium salts are soluble.
Worked example
Nylon-6,6 is made from adipic acid, HOOC-(CH2)4-COOH, and hexamethylenediamine, H2N-(CH2)6-NH2. Each acid reacts with an amine to form an amide bond and release water. Because each monomer has two functional groups, the chain grows in both directions, giving a condensation polymer. The 6,6 refers to six carbons in each monomer.
Traps
Classifying nylon as an addition polymer, confusing terylene's ester linkage with an amide, and saying soaps work well in hard water are common errors.