Synthetic Fibres & Plastics

Synthetic fibres and plastics is chapter 3 in NCERT Class 8 Science books. Synthetic fibres and plastics are beneficial things in our daily lives, they are made up of long chains of repeating units referred to as polymers. There are two types of fibres which are natural and synthetic. Cotton, wool, and silk are natural fibres and they are directly extracted from plants and animals, while nylon, rayon, etc., are synthetic fibres. In this article, let’s learn everything about Synthetic Fibres in detail.

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Synthetic Fibre: Details

Synthetic fibres are man-made fibres with several repeating units manufactured in laboratories or factories by various chemical processes using petroleum products, also known as petrochemicals as raw materials. Different types of synthetic fibres are nylon, rayon, acrylic, and polyester. Nowadays, synthetic fibres are used in considerable amounts in manufacturing various materials such as ropes, fabrics, seat belts, and many more due to their low production cost, durability, and easy maintenance. 

Synthetic Fibres: Definition

Synthetic fibres are made artificially by joining monomers, forming a polymer by this process known as polymerisation. They are made by chemical synthesis by using various reagents and chemicals. Synthetic fibres can be divided into two major categories:

1. Synthetic fibres – Fibres that are fully made using chemicals and reagents are synthetic fibres such as Nylon and Acrylic fibres.
2. Semi-Synthetic fibres– Fibres that are made by using natural raw materials and are slightly modified by using some chemicals are known as semi-synthetic fibres. For example, rayon is made up of cellulose.

Synthetic Fibres: Types

Synthetic fibres are synthesised from a raw material called Petrochemicals. Some examples of synthetic fibres used in the textile are elastane, aramid, nylon, acrylic, polyester and  Polyurethane leather. Different types of synthetic fibres are:

1. Rayon

Rayon is a synthetic fibre made artificially by humans using natural sources as raw material, i.e., cellulose extracted from wood pulp and other agricultural products. Thus, rayon is a synthetic fibre, but it is derived from natural fibre.

1. Rayon is also called artificial silk due to its thin fibres and lightweight.
2. It is used in manufacturing clothes, carpets, curtains, blankets, etc.

2. Nylon

Nylon is a synthetic fibre also known as polyamides. It is completely made up of polymerisation of chemical compounds adipic acid and hexamethylenediamine as monomers.

1. Nylon is made from coal, air, and water.
2. It is strong, elastic, lustrous, and easy to wash.
3. Due to its strength and durability, it is used for making ropes used in rock climbing, fishing nets, carpets, and clothing materials.

3. Polyester

 Polyester is a polymer derived from petroleum. It contains repeated units of ester groups to form polymers.

1. It is popularly used as synthetic fabrics that do not wrinkle. They remain crisp and are easy to wash.
2. Polyester is used in making ropes, jackets, pillows, yarns, etc.
3. Polyester is mixed with cotton to form poly cot fabrics; wool is combined to form poly wool.
4. PET ((polyethylene terephthalate) is another form of polyester used for making bottles, utensils, and many other substances.

4. Acrylic

1. Acrylic may also be called a cheaper version of wool. It means they are not actually wool, but they are Polyacrylonitrile.
2. As they are artificially synthesised, they are cheaper than natural wool.
3. Acrylic is used for making sweaters, blankets, etc.

Synthetic Fibres: Advantages

Advantages associated with using synthetic fibres are listed as follows:

1. Most synthetic fibres have good elasticity.
2. They do not wrinkle easily and remain crisp.
3. They are easily washable.
4. Since these fibres are man made so are available in a variety of colours.
5. They are very strong and durable. Thus can withstand heavy weight without breaking.
6. Synthetic fibres are cheaper than natural fibres.

Synthetic Fibres: Disadvatages

Disadvantages related to using synthetic fibres are listed as follows:

1. While ironing synthetic clothes, one should be very attentive as they tend to melt away easily.
2. Synthetic clothes are not comfortable to wear during summers as they do not absorb sweat.
3. They can easily catch fire. This is the reason why cotton clothes are recommended to wear while cooking.
4. Synthetic fibres are non-biodegradable and hence cause pollution.

Natural and Synthetic Fibres: Differences

The difference between natural and synthetic fibres are explained below:

Synthetic Fibres and Plastics

Plastics are also polymers. Like synthetic fibres, they too have monomer units. Plastics may be linear as well as cross-linked polymers. We constantly use plastic materials in our daily life because they are easily moldable. We can make different plastic products due to this reason. They are also easy to carry and transport. Plastics are of two types:

Thermoplastics: The type of plastics that can be remoulded on heating as they melt and become soft and again become hard when cooled, are known as thermoplastics. Examples: Polythene, propylene, etc.

Thermosetting Plastics: Heavily branched plastics that cannot be remoulded as they become hard on heating are known as thermosetting plastics. Examples: Bakelite, urea-formaldehyde resins, etc.

Plastics: Characteristics

1. Plastics are non-reactive. Due to this reason, they do not corrode as they do not react with water and air.
2. Plastics are light, strong, and durable.
3. They can be moulded into various shapes.
4. Plastics are cheaper than metals. Nowadays, plastic containers are very widely used.

Apart from various advantages, plastics are having various negative aspects such as:

1. They are non-biodegradable in nature and can cause many environmental and health hazards.
2. Burning plastic causes air pollution as they release many toxic gases that are even carcinogenic.

Plastics: Uses

1. It is used in making plastic toys.
2. Plastics are widely used in packaging various products.
3. Plastics are used in making bottles.
4. Teflon is a plastic used for making non-stick pans.

Summary

Fibres are of two types based on their origin: Natural fibres and Synthetic fibres. Natural fibres are extracted from plants and animals, while synthetic fibres are manufactured from chemicals. In short, we can say that synthetic fibres are artificially made fibres in chemical laboratories that consist of many repeating units known as polymers.

Just like natural fibres, synthetic fibres can be woven into a fabric. Synthetic fibres have a wide range of uses varying from household articles like ropes, buckets, furniture, plastic containers, etc., to highly specialized uses such as ships, aircraft, spacecraft, health care, etc.

Various types of synthetic fibres are Rayon, Nylon, Polyester, and Acrylic. Synthetic fibres are much more durable, strong, and cheaper than natural fibres. Clothes made from synthetic fibres are effortless to maintain and wash.

In this manner, we can conclude that synthetic fibres have different and enhanced properties than natural fibres. However, they have certain disadvantages also like non-biodegradable and melting properties. But, when we look into their advantages and uses, they are of immense importance.

Frequently Asked Questions

Frequently asked questions related to synthetic fibres are listed as follows:

Q. Which of the following is a synthetic fibre among jute, nylon, cotton, and wool?
Ans: Among all these fibres, nylon is synthetic fibre. It is completely made up of polymerisation of chemical compounds adipic acid and hexamethylenediamine as monomers.

Q. Why are some fibres called synthetic?
Ans: Some fibres are called synthetic fibres because these are manmade fibres synthesised by using chemicals. These are made up of small units (monomers) that join together to form long chains. Some of the examples of synthetic fibres include nylon, rayon, acrylic, polyester, etc.

Q. Is nylon a synthetic fibre?
Ans: Nylon is a synthetic fibre as it is completely made up of polymerisation of chemical compounds such as adipic acid and hexamethylenediamine as monomers.

Q. What is the difference between natural and synthetic fibres?
Ans: The basic difference between natural and synthetic fibres is that natural fibres are directly extracted from natural substances like plants and animals. For example, cotton and jute are extracted from plants, while silk is extracted from silkworms, and wool is extracted from the hairs of sheep. On the other hand, synthetic fibres are completely man-made and are synthesised from petrochemicals like nylon, rayon, polyester, etc.

Q. Is rayon a synthetic fibre?
Ans: Rayon is synthesised from regenerated cellulose fibres. Cellulose is purified once they are obtained from wood pulp which is converted into the soluble compound, and then they are processed in multiple steps to form a synthetic fibre. Though rayon is obtained from natural substances they are formed by manmade techniques thus, it is a synthetic fibre.

We hope this detailed article on synthetic fibres is helpful to you. If you have any queries on synthetic fibres, ping us through the comment box below and we will get back to you as soon as possible.