Thermoplastic polymers Properties Examples of use Low-density polyethylene (LDPE) Soft and flexible. Not very strong Carrier bags, detergent bottles, packaging High-density polyethylene (HDPE) Strong Bowls, buckets, milk crates Polypropylene (PP) Can be bent or flexed many times without breaking. High impact strength for a polymer Lunch boxes, plastic chairs, children’s toys High-impact polystyrene (HIPS) Light but strong Vacuum-formed packaging and casings Acrylic (polymethyl methacrylate – PMMA) It can be transparent, like glass, or coloured with pigments. Hard wearing and will not shatter on impact Plastic windows, bath tubs, display sign Polyvinyl chloride (PVC) Stiff and hard wearing Pipes, coverings for electric cables, floor and wall coverings, packaging © Nelson Thornes 2011
Thermosetting polymers Properties Examples of uses Epoxy resins Good resistance to chemicals and wear. Strong when reinforced Adhesives, printed circuit boards Melamine formald- hyde Good strength. Resistant to scratches Laminates for work surfaces, plastic plates Urea formald- hyde Good strength, but brittle – it will break rather than change shape Electrical fittings, light sockets, switches, plugs © Nelson Thornes 2011
Types of metal Metal Alloy or pure metal? Ferrous or non- ferrous Properties Typical uses Mild steel Alloy (Iron with 0.15–0.35% carbon Ferrous Strong, cheap, needs to be protected from rusting Building frames, car bodies High speed steel Alloy (Iron with 0.8-1.5% carbon) Very hard and strong Tools Stainless steel Alloy (Iron with chrome and nickel) Hard, tough, resistant to corrosion Sinks, knives and forks, dishes © Nelson Thornes 2011
Types of metal Metal Alloy or pure metal? Ferrous or non- ferrous Properties Typical uses Aluminium Pure metal Non- ferrous Lightweight, strong for its weight, easier to shape than steel Cooking pans, aircraft frames, drinks cans Copper Expensive, easier to shape than iron. Electricity flows through it really well Pipes and plumbing fittings, electrical wires Zinc Corrosion resistant. Zinc has a lower melting point than many metals, so it is easier to mould Camera bodies, handles for car doors Brass Alloy (65% copper and 35% zinc) Strong, good corrosion resistance Castings and ornaments, door knobs © Nelson Thornes 2011 5