Plastics

Origins of Plastics

crude oil, not much use, mixture of hydrocarbons, separated in oil refinery by fractional distillation

4% of oil is used to make plastis

Making Plastics

simple hydrocarbons separated into monomers

monomers react together to form a chain called polymers

Properties of plastic

cheap to make, durable and molded easily

polythene

high density hard and rigid, plastic crates and dustbins

low density soft and flexible used to make plastic bags and bottles

polysterene

yoghurt pots, expanded by blowing gas into it during molding, gives polymer low density and excellent insulation

easily dyed and are good insulators of heat and electricity

low densities, used because they are light

examples

Environmental impact of plastics

don;t break down form water, air or bacteria

have additives added to breakdown

fire risks, poisonous fumes are created,

PVC (Polyvinylchloride) releases hydrogen chloride as it burns

heating

two categories melt when heated and do not melt when heated

polythene

bags, fertiliser sacks, squeezy bottles, lunch boxes

strong, cheap flexible

rigid PVC

pipes, gutters, window frame, floor tiles, curtain rails

strong, long lasting, weather resistant

flexible PVC

insulation electrical wires, hospipes, shower curtains

strong, long lasting, flexible insulator

Polystyrene

food containers, yoghurt pots, electrical components

strong, brittle, rigid, electrical insulator

Nylon

tights, carpets, ropes, combs, brushes, gear wheels

spun into fibres, hard wearings, slippery

Expanded plysterene

packaging, wall insulation, disposable coffee cups

low density, good heat insulators