Chapter =>3 (Synthetic Fibres And Plastics) Definitions

These are Definitions of Chapter => 3 (Synthetic Fibres And Plastics ) Of Class 8,

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Definitions:

1. Plastics => Plastics is also a polymer like the     synthetic fibre. Plastics articles are available       in all possible shapes and sizes. In some             plastics it is linear, whereas in others it is          cross-linked.

2. Fibres => Fibre is a natural or synthetic substance that is significantly longer than it is wide.              Fibres are used for making a large variety of household articles.

3. Synthetic => Natural fibres like cotton, wool, silk, etc., are obtained from plants or animal. The         synthetic fibre , on the hand, are made by human beings. That is why these are called synthetic or       man-made fibres.

4. Synthetic Fibre => A synthetic fibre is a chain of small units joined together. Each small unit is         actually a chemical substance. They are more durable and affordable which makes them more             popular than natural fibre.

5. Fabrics => Fabrics are made from fibres obtained from natural or artificial sources. Fabric                 obtained from silk fibre was very costly

6. Natural Fibres => Natural fibers are those that come from a plant, animal or mineral source.             Cotton and linen are examples of plant fibers, while silk and wool come from animal sources.             Asbestos is a natural mineral fiber.

7. Artificial Fibres => An artificial fiber is a threadlike material invented by human researchers. Such     fibers do not exist naturally. Some examples of artificial fibers include nylon, rayon, Dacron, and       Orlon.

8. Polymer => Many such small units combine to form a large single unit is called a polymer. The         word ‘polymer’ comes from two Greek words; poly meaning many and mer meaning part/unit. So,     a polymer is made of many repeating units. Polymer occur in nature also.

9. Cellulose => Cotton, for example, is a polymer called cellulose. Cellulose is made up of a large        number of glucose units.

10. Rayon => Fibre was obtained by chemical treatment of wood pulp. This fibre was called rayon or    artificial silk. Although rayon is obtained from a natural source, wood pulp, yet it is a man-made         fibre. It is cheaper than silk and can be woven like silk fibres. It can also be dyed in a wide variety     of colours. Rayon is mixed with cotton to make bed sheets or mixed with wool to make carpets.

11. Nylon => Nylon is another mad-made fibre. It was prepared from coal, water and air. It was the        first fully synthetic fibre. Nylon fibre was strong, elastic and light. It was lustrous and easy to            wash.

12. Polyester => Polyester is another synthetic fibre. Fabric made from this fibre does not get              wrinkled easily. It is actually made up of ester.

13. Ester => Esters are the chemicals which give fruit their smell. Polyester (poly+ester) is actually       made up of the repeating units of a chemical called an ester.

14. Polycot => Polycot is a mixture of polyester and cotton.

15. Polywool => It is a mixture of polyester and wool.

16. P.E.T => It is a very familiar form of polyester. It is used for making bottles, utensils, films,          wires and many other useful products.

17. Terylene => It is a popular polyester. It can be drawn into very fine fibres that can be woven like       any other yarn.

18. Acrylic => We wear sweaters, shawls and blankets in the winters. Many of these are actually not      made from natural wool, though they appear to resemble wool. These are preared from another type    of synthetic fibre called acrylic.

19. Petrochemicals => All the synthetic fibres are prepared by a number of processes using raw               materials of petroleum origin, called petrochemicals.

20. Polythene => Polythene (poly-ethene) is an example of a plastic. It is used for making commonly     used polythene bags.

21. Thermoplastics Plastics => Plastics which an deformed easily on heating and can be bent easily       are known as thermoplastic. Polythene and P.V.C are some of the examples of thermoplastics.

22. Thermosetting Plastics => Plastics which when moulded once, cannot be softened by heating. These are called thermosetting plastics. Examples are bakelite and melamine.

23. Biodegradable => A material which gets decomposed through natural processes, such as action by bacteria, is called   biodegradable.

24. Non-Biodegradable => A material which is not easily decomposed by natural processes is termed non-biodegradable.