8.- What are the properties of cellophane, PVC and “Teflon"? How many uses can you think of for each one? Cellophane PROPERTIES USES Transparent Packaging Flexible Wrapping Resistant Shiny Adhesive PVC PROPERTIES USES Strong Tubes and pipes Waterproof Shoe soles Durable Gloves Waterproof clothing Hosepipes Teflon PROPERTIES USES Non-stick Kitchen utensils High heat resistance Paints Durable Aircraft and rocket exterior 9.- What's the difference between hard and expanded polystyrene? What's another name for expanded polystyrene? Hard polystyrene is transparent and can be coloured. It is used to make • CDcases • coat hangers • dairy products containers • egg boxes Expanded polystyrene is porous and soft. It is used in • packaging • thermal and acoustic insulation Expanded polystyrene is also called Porexpan. 10.- In your exercise book, list the uses of each of these thermostable plastics: melamine, polyurethane, Bakelite and polyester resins. Melamine small electrical objects thermal and acoustic insulation kitchen surfaces plates and food containers Polyurethane foam rubber for cushions sponges thermal and acoustic insulation glues and varnishes Bakelite kitchen utensil handles covers for electrical appliances electric plugs and switches Polyester resins crash helmets bodywork for cars and boats fishing rods 11.- Which plastics would you recommend to a business executive who wanted to manufacture the following? a) a container for storing and transporting food Polypropylene, Melamine b) CD cases Polystyrene c) tyres for vehicles Natural rubber or synthetic rubber d) mattresses Synthetic rubber or natural rubber 12.- Which thermostable plastics do we use for acoustic insulators? Polyurethane & Melamine 13.- Name a plastic used in each of the following sectors: medicine, transport, construction and the textile industry. Medicine PVC (gloves) Nylon (toothbrushes) Transport Polyester resins (bodyworks) Natural or Synthetic rubber (tyres) Construction PVC (tubes and pipes), Polyurethane & Melamine (insulators) Textile industry Nylon (fabrics), PVC (waterproof clothing) 14.- What are the characteristics and uses of neoprene? Neoprene is harder and more resistant than synthetic rubber and waterproof. It is used in making diving suits, hosepipes and gloves. 15.- Choose the correct answer to the following questions and write each one in your exercise book. Which of the following plastics become soft when heated and can be reshaped? a) Bakelite b) Thermoplastics c) Thermostable plastics d) Natural rubber and neoprene Transparent film used for wrapping food is made from: a) PVC b) Polythene c) Melamine d) Polystyrene Covers for electrical appliances are made from: a) Polyurethane b) Bakelite c) PVC d) Melamine.