Synthetic Fibres And Plastics

Fabrics are made of fibres which are obtained from natural and artificial sources. Wool, silk, and cotton are a few examples of natural fibres and fibres like polyesters and terylene are a few examples of synthetic fibres.

Natural Fibre

The naturally occurring fibres that humans derive from plants or animals are known as natural fibres. Eg: cotton, wool, silk, etc.

· Basic component of animal fibres is Protein

Synthetic Fibre

Fibres that are made or created by humans are known as synthetic or man-made fibres.
Humans have been able to make a variety of synthetic fibres. Eg: rayon, nylon etc.
Synthetic fibres may be synthesised by two ways:

· By regenerating them from natural fibres, like in rayon.

· By using entirely chemicals and chemical reactions, like in nylon.

Synthetic fibres have many advantages as compared to natural fibres. Some of them are as follows:

They are very strong and durable.
They are cheaper in cost as compared to natural fibres.
They absorb less water and are quick to dry.
They do not shrink.
They are very useful for saving our trees and animals as they are made up of chemicals.
They are moth and insect resistant.

Some common synthetic fibers

Rayon

Rayon made from natural sources such as wood pulp (cellulose) and then chemically converted into a soluble compound so considered as a man-made fiber.
Rayon looks like silk so it is also known as artificial silk.
it is inexpensive than silk but can be woven like silk fibres.

Properties of rayon are:

· Rayon is a versatile fibre.

· It can be dyed in different colours.

· It is silky in touch but stronger than silk.

Uses of rayon are:

· It is used to make apparels like shirts, blouses, etc.

· It is used to make furnishings and upholstery.

Nylon 66:

Nylon is the strongest amongst all the synthetic fibres. It is fully synthetic polymer which is prepared from coal, water and air. It is a polymer of amides. It was made in 1931 for the first time. It was used as a supplement of silk when silk got deficient during World War II for many military applications.

Uses of Nylon

· Nylon is used in toothbrushes, combs, etc.

· It is used to make parachutes, tents, ropes, etc.

· It is used to make socks and stockings as it is elastic.

· It is widely used for making clothes, carpets, etc.

Properties of Nylon

· It melts on heating.

· It absorbs less water.

· It is resistant to moths and fungi.

· It has high tensile strength.

· It is durable.

Polyester

Polyester could be blended with natural fibres to enhance its properties.
Polyester is made of repeating units of a chemical called an ester.
Ester is sweet-smelling compound.
It is best suited for the making of dress materials as it is crisp and is easy to wash.

The common varieties of polyester are:

PET (Polyethylene terephthalate)
Terrycot: It is made by blending polyester and cotton.
Terrysilk: It is made by blending polyester iaiid silk.
Terrywool: It is made by blending polyester and wool.

Acrylic Fibre

Acrylic is a synthetic fibre that resembles wool so also known as artificial wool.
The wool obtained from natural sources is quite expensive, whereas clothes made from acrylic are relatively cheap.
Synthetic fibres are more durable and affordable which makes them more popular than natural fibres.

Polymers

Polymers are compounds that are made up of same, small repeating units calles monomers, joined together through bonds in a linear pattern. There is two type of arrangement in linking monomers:

(a) linear arrangement of units in plastic.
(b) cross-linked arrangement of units in plastic.

Cellulose is a natural polymer made up of large number of glucose units.

Plastic

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.
Plastic can be recycled, reused, coloured, melted, rolled into sheets or made into wires. That is why it finds such a variety of uses.
Plastics are those substances which are mostly synthetic in nature, obtained mainly from petrochemical sources and can be moulded into different shapes.

Properties of plastics are:

Plastics are non-corrosive in nature, i.e., they do not react easily with air and water. They are unaffected by most of the chemicals in normal conditions.
Plastics are the bad conductor of heat. They do not get heated up like metals.
Plastics are non-biodegradable, i.e., they do not get decomposed by microorganisms.

· They are light in weight and durable.

Plasticity is the property of materials by which they can be moulded into any shape.

polythene: it is a kind of plastic and polymer of ethene molecule.

polymerisation: process of joining monomers of same or different kind is called polymerisation.

Types of plastic:

Thermoplastics: Plastic, which gets deformed easily on heating and can be bent easily are known as thermoplastics. Eg: polythene and PVC

Thermosetting Plastics: Plastics, which when moulded once, can not be softened by heating. Eg: bakelite and melamine.

Thermoplastic plastics	Thermosetting plastics
1. Thermoplastic can be easily bent.	1. Thermosetting plastics cannot be easily bent. If forced to bend, they will break.
2. Softens on heating	2. Do not soften on heating
3. Can be moulded and reshaped	3. Cannot be moulded and reshaped.
4. Expensive	4. Cheaper
5. Recyclable	5. Not recyclable
6. Soft and weak	6. Hard and strong
7. It is used in making toys,combs and various containers.	7. It is used in making handles of cooking utensils.
8. Example: Polythene and PVC	8. Example: bakelite and melamine

Biodegradable and Non-Biodegradable Materials

A material that decomposes through natural process is biodegradable and materials that are not easily decomposed by natural processes is termed as non-biodegradable.
Eg: Biodegradable – fruits, paper
Non Biodegradable – plastic, tin

Biodegradable Substances	Non-biodegradable Substances
They are considered safe for the environment	They are considered harmful to the environment
Biodegradable substances are natural wastes	Non-biodegradable substances are synthetic wastes
Biodegradable substances do not cause pollution	Non-biodegradable substances cause pollution
These substances decompose naturally in the environment	These substances do not decompose naturally in the environment
Biodegradable substances have a high rate of decomposition	Non-biodegradable substances have a slow rate of decomposition
Examples of Biodegradable Substances are vegetable wastes, dead plants, dry leaves, flowers, straws, animal excreta, etc.	Examples of Non-biodegradable Substances are rubber, chemicals, paint, plastic, polythene, metals, etc.

Plastics are hazard to environment: plastic is used to make versatile materials but are very dangerous to the environment.

Plastic takes several years to decompose, it is not environmental friendly.
It causes pollution.
The burning process in the synthetic material is quite slow and it does not get completely burnt easily.
It releases lots of poisonous fumes into the atmosphere causing air pollution in the process.
If the plastics are disposed in drains, they choke the drains causing waterlogging.
If these plastics are swallowed by the innocent animals along with their food, they harm their di-gestive system which leads to their death.
They are manufactured by the consumption of a large amount of petroleum.

Strategies for plastic waste management are:

· We should use paper bags and jute bags instead of using plastic bags.

· The government should ban the use of plastic bags.

· Plastics should be recycled to make other useful products which do not harm the environment.

· We should use a special garbage bins to dispose plastic wastes.

· We should not throw plastic wastes in water bodies.

· Practicing 4R’s principle, i.e., Reuse, Recycle, Reduce and Recover should be encouraged.

Is using plastics for storing food safe?

Though storing and carrying food in plastic container is more efficient. But chemicals used for manu-facturing plastics leeches out into the food and contaminates it. Though it is in very small amount but continuous use of it is exposing our body to harmful and poisonous chemicals.

Teflon: it is a kind of plastic used in kitchen ware and makes them non stick.

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