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Synthetic Fibres and Plastics Notes for Class 8, CBSE Notes based on NCERT

Important topics covered:

  • Introduction to fibres and plastics
  • What is synthetic fibre?
  • Types of synthetic fibres
  • Characteristics of Synthetic Fibres
  • Plastics
  • Plastics and the Environment

Introduction to synthetic fibres and plastics class 8:

  • In modern days fabrics are of great use.
  • We use it in clothing, medical, agriculture etc. sector.

Classification of fibres:

Fabrics are classified into two categories. They are:

natural and synthetic fibres

What is Natural fibre?

  • Those fibres which are obtained from natural sources are said to be natural fibres.
  • Silk, cotton, wool are some examples of natural fibres.

What is Synthetic fibre?

  • Those fibres which are man-made are said to be synthetic or artificial fibres.
  • Small units of chemicals, when joined together in the form of a large chain, forms synthetic fibre.
  • The chain so formed is said to be polymer.
  • Rayon, nylon, polyester are some examples of synthetic fibres.



  • Polymer is a Greek word in which ‘poly’ means many and ‘mer’ means unit. Polymer is formed of many repeated units. Each unit is called a monomer.
  • There are natural polymer too i.e. cotton is a polymer of cellulose.
  • All synthetic fibres, like Rayon and Nylon, are polymers.
  • When small monomer units are linked together to form polymers, then this process is said to be Polymerization.

Types of synthetic fibres:

There are mainly four types of synthetic fibres. They are:


rayon fibre

  • Rayon fibre is obtained by chemical treatment of wood pulp.
  • It is also known to be artificial silk.
  • It is much cheaper than silk.
  • It absorbs moisture easily hence comfortable for wear.

Uses of rayon:

  • Rayon can easily be dyed in different colours.
  • Also, it can easily be woven like natural silk.
  • It is mixed with wool to make carpets and blankets.
  • Rayon is used in making bedsheets by mixing it with cotton. Also, shirts and sarees are made from it.
  • Because of its strength, it is used to make automobile tyre cords.


nylon fibre

  • Nylon is entirely synthetic fibre as it is prepared without using any natural raw materials.
  • It is elastic, light weighted and strong fibre.
  • Shows characteristics of lustrous or semi-lustrous.
  • It is easy to wash and is of high tencity fibre with good elasticity.
  • It is weather and water resistant.
  • Dries quickly.

Use of nylon fibres:

  • It is used in making ropes.
  • Used in making seatbelts, sleeping bags, toothbrushes, tents etc.
  • Parachutes as well as ropes for rock climbing are made with nylon.
  • Also, used in making clothes.


polyester fibre

  • It is one of the most popular man-made fibres.
  • Polyester (poly + ester) is made of repeating unit (monomer) of a chemical called ester.
  • Ester is the chemical which provides smell to the fruits.
  • It doesn’t wrinkle easily thus, easy to wash.

Uses of Polyester:

  • A polyester named Terylene is used in dress material.
  • Used in making films, magnetic recording tapes, etc.
  • Sailboats are prepared from polyesters.
  • Firefighters make water horses with it.
  • PET (Poly Ethylene Terephthalate), used for making bottles, utensils, films, wires and many other items.


acrylic fibre

  • It is a strong, lightweight and warm synthetic fibre.
  • Its characteristics resemble with wool.
  • It is available in number of colours.
  • It is more durable and affordable than natural wool.
  • Acrylic fibre, fabric, plastic or paint are made from acrylic acid.

Uses of acrylic fibres:

  • Used in making sweaters.
  • Used in equipping fabrics and carpets.
  • Industries make fake fur used for making toys and fur accessories.
  • Make garments for babies.

Characteristics of synthetic fibres:

Synthetic fibres possess the following characteristics:

  • Synthetic fibres are manufactured from petrochemicals.
  • Durable and inexpensive.
  • Colour resistant.
  • It doesn’t shrink when washed.
  • Lightweight, smooth and soft than any other fibre.
  • Easy to maintain as compared to natural fibres.
  • Easily washed and dried.
  • Wrinkle-free makes them more demanding in the clothing industry.
  • Their tenacity is appreciable thus used in many industries.

Why synthetic clothes should not be worn in the kitchen?

Synthetic clothes have a tendency to melt easily on heating. With any cause, if clothes catch fire, the synthetic fabric will melt and stick to one’s body. It can cause major damage to one’s body. Hence it is recommended to not wear synthetic clothes in the kitchen.



  • The word ‘plastic’ is derived from the Greek word ‘plastikos’ meaning ‘that can be moulded or shaped’.
  • It is like synthetic fibre which can be moulded in different shapes.
  • The linking of monomers of plastics are in varied way.
  • In some plastics, monomers are linked in a linear fashion while in other cases they are cross-linked.
  • We can recycle and reuse it.
  • It can also be melted, made into wires, rolled into sheets, and coloured.
  • They possess high resistance towards corrosion and chemicals.
  • Also, they have low-slung thermal and electrical conductivity.
  • Possess a high ratio between strength and weight.
  • Have resistance for shock and water.
  • Plastic’s availability in vivid colours, inexpensiveness and low toxicity make it find good use in the market.

Uses of plastics:

  • In making toys, chairs, bags, brush, disposable cups, tables, headliners, bottles, pen drives, cabinets, electrical connectors, suitcases,  and many other innumerable stuffs.
  • Cookware is made from plastics which we use in microwave ovens.
  • Melamine is a polymer used to make fireproof uniforms for firefighters.

Plastics and environment:

environmental effect of plastics

  • Plastic is a non-biodegradable material.
  • It doesn’t decompose or takes many years to get decomposed.
  • Plastic has become a major threat to our environment.
  • If we feel around us, life seems impossible without the use of plastics. Inside our home to outside almost all the things either in one way or the other use plastics.
  • Due to its non-biodegradable property, it gets accumulated in the environment.
  • When it is burnt, releases a lot of poisonous gas in our air, thus causes air pollution.

Biodegradable and non-biodegradable material:

  • Biodegradable material: Those materials which decompose easily by natural processes like bacterial action are called biodegradable material. Tree leaves, food wastes etc. are some examples of biodegradable material.
  • Non-biodegradable material: That material which cannot be easily decomposed by natural processes is called Non-biodegradable. Plastics, detergents are some examples of a non-biodegradable material.

4R’s to save our environment:

4R's to save environment

  • Refuse: We should avoid usage of unnecessary materials like refuse plastics given by shopkeeper by carrying your own bag every time.
  • Reduce: We should reduce/ minimize the use of non-biodegradable material like plastics.
  • Reuse: Reuse the material which can be used like the empty bourn-vita jar that can be used to store pickle.
  • Recycle: In our home, we come across many things which can be recycled in industry like old newspaper, plastics, metals, batteries etc.
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