7.7 - Uses of Metals & Polymers

Why a polymer suits its job

Plastics are materials made up of polymer molecules, with shared properties that make them widely useful.

Properties polymers share

• Usually cheaper than metals and ceramics.
• Generally strong.
• Low density compared to most metals and ceramics.
• Many are flexible and almost all can be moulded into shape.
• Thermal and electrical insulators.
• Resist corrosion and don't rot.

Individual polymers and their uses

• Poly(ethene) (polythene) - low density, flexible, easy to mould, unreactive, waterproof, and an electrical insulator. Used for carrier bags, bottles, and electrical wire insulation.
• Poly(propene) - Low density, rigid, tough, and easy to mould. Used for packing crates, moulded furniture, and ropes.
• Poly(chloroethene) (PVC) - rigid, hard, strong, unreactive, and fire resistant. Used for drainpipes, water pipes, and window frames.
• Poly(tetrafluoroethene) (PTFE) - tough, strong, high melting point for a polymer, unreactive, and extremely non-stick. Used for non-stick pan coatings, and for waterproof and stain-resistant clothing because water and stains do not stick to it.