AQA - A Level: Product Design - Paper 1 Exam

3 Types of plastic - ansThermoplastics- can be reheated and reshaped as they have loose monomer chains, can be recycled and coloured pigments can be added to make it more aesthetically pleasing. Thermosets - undergo a chemical change so permanently rigid, cannot be reheated or reshaped as it forms rigid cross links, e.g. spoons. Elastomers - can be distorted under pressure but will return to their original shape. Properties of plastics - ans-Electrical and thermal insulators. -Good strength to weight ratio. -Good atmospheric and chemical corrosion resistance. -They are lightweight. -Fairly low melting points (thermoplastics). -They can be self-coloured, opaque, translucent or transparent. ABS - ansHigh impact strength, giving good toughness and strength, scratch- resistant, lightweight, durable. Kitchen products, mobile phone cases, safety helmets, toys, car parts Injection moulded. PC - ansGood chemical resistance, expensive, very tough, high melting point. Protective shields, safety hats and glasses, hairdryer bodies, telephones. Injection moulded. PP 5 - ansLightweight, food safe, good impact and chemical resistance. Food containers, medical equipment, string and rope. Injection moulded. HIPS - ansGood impact resistance, good strength and stiffness, lightweight. Toys and refrigerator linings. Vacuum formed. PMMA 7 - ansAcrylic. Food safe, tough, hard, durable, easily machined. Light units, illuminated signs, lenses for car lights. Hand/CAM cut. HDPE 2 - ansGood stiffness, good chemical resistance. Crates, bottles, buckets, bowls.