Synthetic fibres and plastics Worksheet-2

Synthetic fibres and plastics Worksheet-2

1. Which material is used for making plugs, switches?

2. Name the plastic used for making non-stick pans.

3. Give one reason to support the use of teflon in non-stick pans.

4. Classify the given polymers into thermoset and thermoplastic.

(a) Melamine         (b) Thermocol

5. What is a polymer?

6. What are synthetic fibres?

7. Give examples which indicate that nylon fibres are very strong.

8. Name the plastic whose sheets are used for packing liquids.

9. Why is teflon used as tape for sealing purpose?

10. What are natural fabrics?

11. What are natural polymers? Give two examples.

12. How is artificial silk made?

13. Is rayon a natural fibre?

14. Name the first fully synthetic fibre.

15. Why nylon is used for making parachutes?

Answer:

1. Bakelite is a poor conductor of heat and electricity hence it is used for making electrical switches.

2. Polytetrafluoroethylene PTFE (Dupont’s Teflon) is used for making non stick pans.

3. Teflon is a special plastic in which oil and water do not stick. Food can be cooked with minimum oil in Teflon coated pans.

4. Melamine is a thermoset polymer.  Thermoset polymers can be moulded once and cannot be softened by heating.

Thermocol is a thermoplastic polymer. Thermocol is a polymer of styrene. It is solid at room temperature. It can be melted at high temperature.

5. Polymers are substances containing a large number of small molecules (called monomers) that are linked together to form long chains. Because of their large size, polymers are classified as macromolecules.

6. Manmade fibres are called synthetic fibres. For example: Nylon, orlon.

7. Nylon is used for making ropes, tents, car seat belts which shows that Nylon fibres are very strong.

8. Polyethylene terephthalate commonly abbreviated PET is used for making containers for food and other liquid substances.

9. Teflon is a special plastic on which oil and water do not stick.  Hence teflon is used a tape for sealing purpose.

10. Fabrics woven from fibres obtained from plants and animals are called natural fabrics. For example: Jute fabrics, cotton fabrics, Silk

11. Polymers found in living organisms are called natural polymers. For example Cellulose and starch are polymers of glucose, Protein is a polymer of amino acids.

12. Rayon or artificial silk is obtained by chemical treatment of wood pulp.

13. Rayon is a manmade fibre. It is obtained by chemical treatment of wood pulp.

14. Nylon is the first fully synthetic fibre. It was obtained from coal, water and air.

15. Nylon fibres are strong, elastic and light hence are used for making parachutes.