Synthetic Fibres and Plastics

Cotton, wool and silk fibres are obtained from cotton plant, sheep and silkworm, respectively. It means that they are obtained from natural sources. But, nylon is synthesized by the use of chemicals. Hence it is not a natural fibre.

Polymers can be made in both ways. Cotton is a polymer of cellulose.

Rayon is also known as artificial silk because many of its properties are similar to that of natural silk fibre.

Rayon or artificial silk is used to make bed sheets and carpets by mixing it with other natural fibres, like cotton and wool. It can take up a variety of colours. Silk is a naturally obtained fibre and is not obtained by mixing rayon with wool.

Cotton, silk and wool are natural fibres, while polyester is a synthetic fibre. Natural fibres are costlier and need more maintenance. So, one should buy polyester.

Swimwear has nothing to do with the strength of fibre or its warmth. Swimwear should have an easy contact with water and it should also get dried up quickly. Nylon possesses dip and dry property, therefore it is used to make swimwear.

The most essential characteristic for selecting a material for making parachutes and ropes for rock climbing is its high tensile strength. Nylon fibres are stronger than even a steel wire and have very high tensile strength. Therefore, it is used for making parachutes and ropes.

The fibre used for making cloth should have certain characteristics like it should be light in weight and should not have a dull surface, i.e. should be shiny/lustrous. It should be strong/durable and should possess some elasticity. These characteristics make nylon fibre a suitable choice for making cloth.
High tensile strength, easy moulding and being a regenerated fibre are also the characteristics of nylon, but these are not the requisite properties for using it make cloth.

Polyester is a synthetic fibre which does not wrinkle easily. Teflon is a strong synthetic polymer which can be used to make nonstick cookware. Nylon is stronger than steel wire. Therefore, it is used to make parachutes. Rayon is prepared using cellulose as raw material. So, it is not a fully synthetic fibre.

Nylon, rayon, polyester are synthetic fibres, while cotton is a natural fibre. Natural fibres always soak more water than synthetic fibres.

Umbrella is used to protect oneself from rain. It means that it should soak less water and should get dried up easily. Synthetic fibres possess the characteristic properties of soaking less water and getting dried up easily. Therefore, they are used for making umbrellas.

Both thermosetting plastics and thermoplastics have almost the same tensile strength, durability and flexibility. The main difference between them is that thermosetting plastics once set cannot be moulded again, but thermoplastics can be remoulded on heating.

Electrical switches and handles of utensils made of bakelite do not allow the current and heat to pass through them. Bakelite is a poor conductor of heat and electricity. So, it is used to make switches and utensil handles.

Non-stick coating on cookware should be made of such a material that neither reacts with oil nor allows the oil to stick over it. Teflon possesses both these properties. That is why it is used for coating cookware.

Teflon is non-reactive towards oil. Polythene and polystyrene melt down if they catch fire. Melamine is resistant to fire and is therefore known as a fireproof plastic.

Electric plugs, switches, etc. should be made of such materials, which neither allow the heat nor the current to pass through. Also, they should not melt down on heating. Thermosetting plastics possess these properties. Therefore, they are used for the same purpose.

Handles of screwdrivers and testers should be made of such materials, which do not allow current to pass through them. Otherwise, we may get an electric shock. Plastics are bad conductors of electricity.