Synthetic Fibres and Plastics
Fibre is a type of thread that is strong enough to make clothes, nets, wires, etc. It is obtained from natural and man-made sources. Natural fibres are obtained from plants and animals. Synthetic fibres are obtained from petrochemicals which are raw materials of petroleum origin. A synthetic fibre is a chain of small units called monomers. These monomers combine to form large single unit called polymer.
Depending upon the chemicals used for preparing synthetic fibres the synthetic fibres are of different types.
Rayon is made of cellulose, which is obtained from wood pulp. Due to silky texture, it is also called as artificial silk. It is cheaper than silk and is used as its cheap substitute.
Nylon was the first synthetic fibre. It was prepared from coal, water and air. Nylon fibre is strong, elastic, light, lustrous and easy to wash. Polyester is made from petroleum products. Polyester fibres are strong and absorb very little water.PET (Polyethylene terephthalate), which is a form of polyester, is used for making bottles, vessels, wires etc. Acrylic fibre is used as substitute for wool.
Synthetic fibers are durable, absorb little water and easy to maintain. They are less expensive as compared to natural fibres and are readily available.Clothes made from synthetic fibres shrink and stick to the skin on burning.
Plastics are the synthetic polymers that can be moulded or set into any desired shape when soft and then hardened to make durable articles. Plastics can be formed by linear arrangement of monomers or by cross-linked arrangement of monomers. Thermoplastics and thermosetting are the two types of plastics. Thermoplastics get deformed easily on heating and can be bent into desired shapes on heating again and again.
Thermosetting plastics are those plastics which cannot be remoulded on heating e.g. melamine, bakelite etc. Melamine is fire resistant and is used to make kitchenware, fire proof fabrics etc. Bakelite is used to make electrical switches, handles etc.
Substances that can be decomposed by the natural processes, such as the action of bacteria are known as biodegradable substances. Non-biodegradable are the substances that are not easily decomposed by the natural processes. Plastics produce poisonous gases on burning.They are non-biodegradable, i.e., they are not decomposed by micro-organisms. Hence, they are not environment friendly.
Use of plastics should be minimised and we must follow the four ‘R’ Principle.
The four ‘R’ means Reduce, Reuse, Recycle and Recover.