POLYMERS PROFESSIONAL ENGLISH IN USE FOR ENGINEERING

 

PROFESSIONAL ENGLISH IN USE FOR ENGINEERING UNIT 14. POLYMERS

 

A Natural and synthetic polymers The web page below, from a website for engineering students, provides an introduction to polymers. With names such as polytetrafluoroethyline and polyethyleneteraphthalate, it’s not surprising that polymers are usually called by their common name, plastic. But what, exactly, is a polymer or a plastic. B Thermoplastics and thermosetting plastics The page goes on to look at types of polymer. Synthetic polymers can be divided into two main categories: Thermoplastics can be melted by heat, and formed in shaped containers called moulds. After the liquid plastic has cooled, it sets to form a solid material. A thermoplastic is a type of plastic that can be heated and moulded numerous times. Examples of thermoplastics that are common in engineering include: ·       ABS (acrylonitrile butadiene styrene) – stiff and light, used in vehicle bodywork. ·       Polycarbonate – used to make strong, transparent panels and vehicle lights.     EXERCISES 14.1 Circle the correct words to complete the text. Look at A opposite to help you. A lot of rubber is made from latex, a (1) natural/ synthetic polymer which comes from rubber trees. However, not all rubber comes from trees. Synthetic rubber is a (2) manmade/ natural 14.2 Read the extract describing a plastic panel manufacturing process. Then decide whether the sentences below are true or false sentences. Look at B opposite to help you. By this stage of the process, the plastic is solid, and has fully cooled. Selected panels can now undergo quality – control testing, to check they are strong enough to cope with the tough conditions they will be exposed to in use. 1. The plastic was heated earlier in the process. 2. The plastic has now set. 14.3 Complete the word puzzle and find the word going across the page. Look at A and B opposite to help you. 1. shorter name for polyvinylchloride 2. used for forming melted plastic 3. a group of atoms 4. a long chain of atoms

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