CHAPTER 3: SYNTHETIC FIBRES AND PLASTICS

( FIG 1.1 )

IMPORTANT NOTES:


1. A fabric is the material used for making clothes.


2. Fabrics are made from fibers obtained from a natural or artificial source.


3. Besides clothes, fibers are also used for making carpets, a sail of boats, parachutes, upholstery, and many more items.


4. Fibers can be natural or artificial. Fibers such as cotton, wool, jute, and silk are natural fibers whereas rayon, nylon, and polyester are artificial fibers.


5. The man-made fibers produced from chemical substances are called synthetic fibers.


6. Synthetic fibers are also known as man-made fibers or artificial fibers.


7. Depending upon the types of chemicals used for manufacturing the synthetic fibers they are called rayon, nylon, polyester, and acrylic.


8. Rayon or artificial silk is made from cellulose obtained from wood pulp.


9. It can be dyed in a wide variety of colours.


10. Nylon was the first synthetic fiber produced by man in 1931.


11. Nylon fibers are strong, elastic, light, lustrous, and easy to wash.


12. It is used to make many items like socks, ropes, tents, toothbrushes, car seat belts, curtains, etc.


13. Terylene and Dacron are polyester fibers.


14. It is made from two monomers, terephthalic acid, and ethylene glycol.


15. It is used for making PET bottles, jars, floppy discs, shirts, hats, etc.


16. Acrylic is the synthetic fibre that resembles wool in its texture and properties.


17. It is used to make sweaters, shawls, socks, etc.


18. They dry up soon, are durable, less expensive, readily available, and easy to maintain.


19. A plastic is a synthetic material that can be set into the desired shape when soft and then hardened to produce a durable article.


20. Some plastic polymers have a linear arrangement of units, whereas in others it is a cross-linked arrangement.


21. Thermoplastic is a plastic that gets deformed easily on heating and can be bent easily, e.g., polythene and PVC. These are used for manufacturing toys, combs, containers, etc.


22. Thermosetting plastics are plastic which when moulded once cannot be softened by heating, e.g., Bakelite and melamine.


23. Bakelite is used for making electrical switcheshandles of various utensils, etc.


24. Melamine is used for making floor tiles, kitchenware, etc.


25. Plastic is a non-biodegradable substance. So, the articles made of plastics do not rot when they are thrown away after use. This pollutes the environment.


26. When plastic waste materials are burnt, they produce poisonous gases which pollute the air. The 5R principleReduceReuseRecycleRecover, and Refuse should be our basic mantra to minimize the hazards associated with the disposal of plastic wastes.


27. We must think twice before using plastic items.


( FIG: 1.2 )


IMPORTANT TERMS:


Acrylic: The synthetic fibre that resembles wool in its texture and properties is called acrylic.


Artificial silk: A man-made fibre obtained from the chemical treatment of wood pulp that has properties similar to that of silk is called artificial silk.


Nylon: A fully synthetic polymer that is prepared from coal, water, and the air is called nylon.


Plastic: Those substances which are mostly synthetic, obtained mainly from petrochemical sources, and can be moulded into different shapes are called plastics.


Polyester: The synthetic fibre which is used for making PET bottles, home furnishings, etc., and is blended with natural fibres to enhance its properties is called polyester.


Polymer: The compound that is made up of small repeating units, joined together through bonds in a linear pattern is called a polymer.


Polythene: The compound obtained from ethylene under high temperature, high pressure, and in the presence of a catalyst is called polythene.


Rayon: A man-made fibre that is produced by the chemical processing of wood pulp, which is a natural substance is called rayon.


Synthetic fibres: The fibres which are made by human beings with the help of chemical substances are called synthetic fibres.


Terylene: A common variety of polyester which can be drawn into very fine fibres is called terylene.


Thermoplastics: Those plastics which soften on heating and harden on cooling are called thermoplastics.


Thermosetting plastics: Those plastics, which when moulded once, cannot be softened again and lose their plasticity is called thermosetting plastics.


ONE LINER QUESTION & ANSWER: 

Q1. Name a natural fibre.
Answer: Cotton

Q2. Name the basic component of animal fibres.
Answer: Protein

Q3. Name some artificial fibres.
Answer: Nylon, terylene, PET, acrylic, Teflon, etc.

Q4. Which fibre is known as artificial silk?
Answer: Rayon

Q5. In which country was rayon the first time synthesized?
Answer: England

Q6. Name the first fully synthetic fibre.
Answer: Nylon

Q7. Name the largest producer unit of rayon in the world.
Answer: Grasim India

Q8. Name a common variety of polyester.
Answer: Terylene

Q9. What is an ester?
Answer: Ester is a sweet-smelling compound.

Q10. Name some objects made of plastics.
Answer: Containers, buckets, bottles, chairs, baskets, etc.

Q11. What is polythene?
Answer: Polythene is a polymer of ethene.

Q12. Give some examples of thermoplastics.
Answer: Polythene and polyvinyl chloride.

Q13. Give some examples of thermosetting plastics.
Answer: Bakelite and melamine.

Q14. What is the full form of PVC?
Answer: Polyvinyl Chloride

Q15. What are 5Rs?
Answer: 5R stands for Reduce, Reuse, Recycle, Recover, and Refuse.

Q16. Whether cotton cloth biodegradable or non-biodegradable?
Answer: Biodegradable

Q17. Name the form of polyester which is replacing materials like glass and used for making bottles and jars.
Answer: PET (Polyethylene Terephthalate)

Q18. Which of two is thermosetting plastic—PVC or bakelite?
Answer: Bakelite

Q19. Name a synthetic fibre that is polyamide.
Answer: Nylon

Q20. Give the name of a plastic used for making fibres.

Answer: Nylon