4. Give examples, which indicate that nylon fibres are very strong
5. Name the plastic whose sheets are used for packing liquids.
6. How is artificial silk made?
7. Why nylon is used for making parachutes?
8. Can bacteria break down plastics?
9. Write any tree important properties and uses of nylon.
10. Give the characteristic properties and important uses of the following (i). Polythene (ii). Polystyrene (iii). Teflon
Answers
Answer:
4.As nylon is a very strong fibre, it is used for making parachutes, rock climbing ropes, fishing nets, seat belts. A nylon thread is actually stronger than steel wire.
5.polyethylene terephthalate
6.Artificial silk, or rayon, is made from cellulose, obtained from cotton or wood pulp. The cellulose is dissolved in a substance called alkaline carbon disulphide to make a thick liquid. This is squirted through tiny holes into a bath of acid. It reforms as fibres, which can be spun into yarn.
7.Nylon - Nylon replaced silk during the WW2 when supply of silk diminished. Nylon has since become a popular choice, as it has excellent wind resistance, good elasticity, mildew resistance, and is comparatively cheaper. The material is also lightweight and dries quickly. It is resistant to abrasion and chemicals
8.Scientists have discovered bacteria that are able to biodegrade plastics from polymers back into