Category :
8th Class
Synthetic Fibres and Plastics
Synopsis
- Natural fibres like cotton are obtained from plants, while wool and silk fibres are obtained from animals.
- The rearing of silk worms for obtaining silk is called sericulture.
- Silk fibres are made up of a protein.
- Synthetic fibres are made by human beings.
- A synthetic fibre is also a chain of small units joined together. Each small unit is called a monomer and actually a chemical substance. Many such small units combine to form a large single unit called a polymer.
- Synthetic fibres are durable, less expensive and dry up fast.
- Rayon (artificial silk) is made from wood pulp while nylon is made from coal, air and water.
- Nylon by and far is the most used synthetic fibre.
- Many articles like socks, ropes, tents, parachutes, etc., are made from nylon. A nylon thread is stronger than a steel wire.
- Polyester is made up of esters which is a mixture of acid and alcohol. Polycot, poly wool, terry cot, etc., are the products prepared by mixing two kinds of fibres, both artificial and natural.
- Plastic because of its mouldability finds versatile use. Thermoplastics like PVC and polythene can be remoulded, while thermosetting plastics (like bake lite and melamine) cannot be remoulded.
- Thermosetting plastics are used as kitchenware and also for electrical switches and handles.
- Plastic is non-reactive and does not corrode easily, hence it is suitable as containers of food, but are non-biodegradable. We should reduce the use of plastic.
- Waste created by plastics is not eco-friendly. The burning of plastic releases poisonous gases. Hence, these should not be disposed by burning.
- Polybags carelessly thrown are responsible for clogging the drains and also cause health problems for animals since cows and other stray animals sometimes swallow plastic bags and choke their respiratory systems.
- Use the 4R principle for the use of plastic-reduce, reuse, recycle and recover.
