Natural fibres like cotton, wool, silk, etc., are obtained from plants or animals.
The synthetic fibres, on the other hand, are made by human beings.
That is why these are called synthetic or man-made fibres.
A synthetic fibre is also a chain of small units joined together.
Each small unit is actually a chemical substance.
Many such small units combine to form a large single unit 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.
Cotton, for example, is a polymer called cellulose. Cellulose is made up of a large number of glucose units.
Types of Synthetic
Fibres, Rayon, Nylon
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.
Nylon is another man-made fibre.
In 1931, it was made without using any natural raw material (from plant or animal).
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.
So, it became very popular for making clothes.
Nylon is also used for making parachutes and ropes for rock climbing.
A nylon thread is actually stronger than a steel wire. Polyester is another synthetic fibre.
Terylene is a popular polyester.
PET is a very familiar form of polyester. It is used for making bottles, utensils, films, wires and many other useful products.
We wear sweaters and use shawls or blankets in the winter. Many of these are actually not made from natural wool, though they appear to resemble wool.
These are prepared from another type of synthetic fibre called acrylic.
The wool obtained from natural sources is quite expensive, whereas clothes made from acrylic are relatively cheap.
All the synthetic fibres are prepared by a number of processes using raw materials of petroleum origin, called petrochemicals.
Plastic is also a polymer like the synthetic fibre.
All plastics do not have the same type of arrangement of units.
In some it is linear, whereas in others it is cross-linked.
Polythene (Poly+ethene) is an example of a plastic. plastic which gets deformed easily on heating and can be bent easily are known as thermoplastics.
Polythene and PVC are some of the examples of thermoplastics.
These are used for manufacturing toys, combs and various types of containers.
Some plastics which when moulded once cannot be softened by heating.
These are called thermo setting plastics. Two examples are bakelite and melamine.
Bakelite is a poor conductor of heat and electricity.
It is used for making electrical switches, handles of various utensils, etc.
Melamine is a versatile material.
It resists fire and can tolerate heat better than other plastics.
It is used for making floor tiles, kitchenware and fabrics which resist fire.
Plastics are poor conductors of heat and electricity.
Teflon is a special plastic on which oil and water do not stick. It is used for nonstick coating on cookwares.
A material which gets decomposed through natural processes, such as action by bacteria, is called
biodegradable.
A material which is not easily decomposed by natural processes is termed as non-biodegradable.
Plastic takes several years to decompose, it is not environment friendly.
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