Chapter 3 Synthetic Fibres and Plastics
* Short answer type questions:
Q.1. It is suggested not to burn plasties and Synthetic fibres. Why?
Ans Burning a plastics and synthetic fibres produces poisonous gases which are harmful and causes environmental pollution. So it is suggested not to burn plastics and synthetic fibres.
Q. 2. What is thermoplastic ? Explain with examples .
Ans – The plastics which get moulded easily on heating and which can be bent is called Thermoplastic. They can be bent to make different new items. For example – PVC, polythene, polystyrene etc.
Q. 3. Terycot are made by mixing two types of fibres. Write the name of these fibres.
Ans Terycot are made by mixing two fibres – synthetic and natural fibre j.e. teryleně and cotton.
Q. 4. What is biodegradable substances ?
Ans The substances which dissociate into simpler, harmless substances in the environment are known as biodegradable substances. For example – paper, clothes, fruits and vegetable peels, cardboards etc.
Q. 5. What is polymerisation ?
Ans Poly means ‘mamy’ and mer means ‘part’. Synthetic fibre is a chain small units join together and each small unit is a chemical substance. Many such small units combined to form a large single unit called polymer. This process is called polymerisation. For example — polythene, PVC, cellulose etc.
* Long answer type questions:
Q. 1. Write the use of synthetic fibre in our daily life.
Ans Synthetic fibre are made by human – beings through artificial methods
1. Rayon is mixed with cotton to make bedsheets or mixed with wool to make beautiful carpets.
2. Nylon is used in making ropes which are used in rock climbing and parachutes .
3. Stocking, seatbelts, ropes, tents, toothbrushes, sleeping bag, curtains etc. are made up of nylon
4. Polyester is used for making clothes.
5. Synthetic fibres are more shiny and soft.
6. Synthetic fibres soak less water and dry up easily.
Q. 2. ”Avoid the use of plastics as far as possible.” Comment on this advice.
Ans. Despite of being very useful, plastic is not environmental friendly. It does not get completely burn and not easily decompose by micro – organisms polybags of chips or biscuits, other eatables thrown on the road or in parkswhich are responsible for clogging the drains. These plastic bags when swallowed by animals, it chokes the respiratory system of animals and form Mining in their stómach which causes death of animals, So to avoid these problems, use of cotton and jute bags are preferable.
Q. 3. How is synthetic fibre nylon prepared ? Write various properties of nylon.
Ans. Nylon is made by mixing adipic acid and hexamethy lene diamine. It is completely synthetic fibre.
It has following properties:-
1. Nylon is strong elastic in nature and light in weight.
2. It is lustrous and can be cleaned easily .
3. The clothes made from nylon does not get wrinkled easily and stable for long time.
4. Nylon is durable.
5. It soak less water and dry up easily.
6. Clothes of nylon does not have thread of cloth worn.
7. They do not need extra care.