Title CH 3_Synthetic_Fibres_and_Plastics Outdated.pdf ✅

SCIENCE Chapter 3: Cell – Synthetic Fibres and Plastics
(1) SYNTHETIC FIBRES AND PLASTICS 03 Synthetic Fibres and Plastics Introduction • The clothes which we wear are made of fabrics. • Fabrics are made of fibres obtained from natural or artificialsources. • The fibres obtained from plants and animals are called natural fibres. Cotton, jute, wool and silk are natural fibres. • The synthetic fibres are made by human beings. Rayon, nylon, polyester are synthetic fibres. Synthetic Fibres • A synthetic fibre is a long chain of small units joined together, and each small unit is actually a chemical substance. • A polymer is a very big molecule formed by the combination of a large number of small molecules. • The word polymer comes from two Greek words poly meaning many and mer meaning units. • The small molecules which join to form a polymer are called monomers. Types of Synthetic Fibres Rayon • Rayon is often regarded as artificialsilk. • It is a man-made fibre prepared from a natural raw material called cellulose by chemical treatment. • The cellulose required for making rayon is obtained from wood pulp. • So, rayon is obtained by the chemical treatment of wood pulp. Uses: ✓ In the textile industry for making sarees and dresses ✓ To make carpets ✓ In the medical field for making bandages and surgical dressings ✓ In making bedsheets, curtains and blankets
(2) SYNTHETIC FIBRES AND PLASTICS 03 Nylon Nylon is the first fully synthetic fibre made by man without using any natural rawmaterials. Properties: • It is very strong, elastic, lightweight and lustrous. • They absorb very little water, so clothes made of nylon are easy to wash and dry. • It is wrinkle resistant. Uses: • In making socks, tents, toothbrushes, car seat belts and curtains • For making parachute • In making ropes for rock climbing. Polyester • Polyester is a synthetic fibre. • Polyester (poly + ester) is made of repeating units of a chemical called an ester.
(3) SYNTHETIC FIBRES AND PLASTICS 03 • Terylene is a popular polyester fibre. • Polyester fabric is strong and wrinkle resistant. • It is easy to wash and dry. • Natural fibres (like cotton and wool) are also mixed with polyester to make blended fabrics like polycot or polywool. As the name suggests, these fabrics are made by blending two types offibres. Example: Polycot is a mixture of polyester and cotton. Similarly, polywool is a mixture of polyester and wool. Uses: • In making fabrics for sarees, dress materials and curtains • For making PET bottles, utensils, films, wires and other useful PET products Acrylic Because of its wool-like feel, acrylic fibre is often used as a substitute for wool. Properties: ✓ It is lightweight, soft and warm with a wool-like feel. ✓ It retains its shape and resists shrinkage and wrinkles. ✓ It is strong and durable. Uses: It is used for making sweaters, shawls, blankets, jackets, sportswear, socks, furnishing fabrics and carpets.