Most of the plastics we use today are obtained from crude oil.

There are two main groups of plastics:


Thermoplastics soften when heated and can be shaped. On cooling, they harden. This process of softening and hardening can be repeated over and over again.

Example of Thermoplastic


Properties: light, hard-wearing, strong, easily scratched or cracked; can be formed at temperatures between 160ºC – 170ºC; can be joined using special solvents such as chloroform and tensol cement; transparent, coloured; comes in the form of a sheet, rod or tube

Uses: spectacle lenses, goggles, car light units, signboards, baths,  shower trays


Properties: most common type is in the form of fibres that are woven into a fabric; tough, durable, low frictional properties, easy to machine, can withstand high temperatures

Uses: gears, nuts, bolts, hinges, zips, clothing, bags, tents, ropes, brush handles, fan blades

Polyvinyl chloride (PVC) – Plasticised PVC

Properties: plasticised PVC is soft, flexible, good electrical insulation properties

Uses: waterproof clothing, inflatable air beds, electrical cables, garden hoses

Polyvinyl chloride (PVC) – Rigid PVC

Properties: rigid PVC is light, stiff, hard, resistant to abrasion, resistant to chemicals and solvents

Uses: water pipes, liquid containers, electrical trunking

Polyethylene (polythene) – High Density

Properties: high density polyethylene is strong, stiff, tough, resistant to chemical attack

Uses: liquid containers, buckets, garbage bins, crates, gas pipes, plumbing components

Polyethylene (polythene) – Low Density

Properties: low density polyethylene is weaker, softer and more flexible

Uses: squeeze bottles, garbage and carrier bags, rainwear, drinking cups

Polystyrene – General Purpose

Properties: very brittle

Uses: packaging trays, modelling kits, tape casings, low cost disposable items such as cups and spoons

Polystyrene – High Impact

Properties: tough, flexible, can withstand rough handling

Uses: television and hi-fi casings, refrigerator linings

Polystyrene – Expanded

Properties: light, buoyant, shock-absorbant, good insulator of heat and sound

Uses: swimming float, packaging, thermal insulation, ceiling tiles, beads for bean bags

Thermosetting Plastics

Thermosetting plastics cannot be reshaped by heating once formed.

Example of Thermosetting Plastics

Polyester Resin

Properties: good electrical insulator, good heat resistance, stiff; hard and brittle alone; strong and resilient when laminated

commonly combined with glass fibre to produce glass-reinforced polyester (GRP)/fibreglass -> light, very strong, durable, weather-resistant, easily moulded, coloured

Uses: outdoor structures such as bus-stop shelters, playground equipment, waterslides, boat hulls, car body panels, garden furniture


Properties: stiff, hard, strong, heat resistant; clear material but can be coloured by adding pigments, cannot be stained or scratched easily

Uses: laminates for kitchen worktops and dining tables, non-breakable tableware such as plastics bowls, plates and cups


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