CBSE Class 8 Science Chapter 3 Revision Notes

Chapter 3: Synthetic Fibres And Plastics Revision Notes

  • All synthetic fibres are man-made fibres created through processes, including petroleum-derived raw materials known as petrochemicals.
  • Synthetic fibres are made up of numerous small chemical units called monomers that come together to form a bigger unit known as a polymer.
  • Rayon, Nylon, Polyester, and Acrylic are the terms given to synthetic fibres based on the chemicals used to manufacture them.




  • Rayon is a fabric created from wood pulp cellulose and can be woven like silk fibres.
  • Containers, car upholstery, and other items are made from it.

(ii) Nylon:

  • It is a fibre made from coal, water, and air.
  • It’s light, robust, and long-lasting.
  • The fabric dries fast and allows for simple evaporation.
  • It’s found in parachutes, ropes, military clothing, socks, and tyres, among other things.

(iii) Polyester:

  • This man-made cloth is both versatile and significant.
  • It has the remarkable ability to resist wrinkles and is easy to clean.
  • It is both hard and soft.
  • Examples are terylene and PET
  • It’s found in dresses, suits, and rainwear, among other things.

(iv) Acrylic:

  • A synthetic fibre that resembles wool and is used to produce sweaters, blankets, shawls, and other items.
  • It is soft, lightweight, and toasty.
  • It is also less expensive than real wool.
  • Chemicals, moths, and sunlight have no effect on it.
  • As a result, they are frequently used presently.


  1. Quick dry materials
  2. Durable
  3. Cost-effective
  4. Readily available and
  5. Easy to maintain


  • Plastics are a polymer, just like synthetic fibres.
  • Some plastics have a linear unit organisation, whereas others have a cross-linked unit arrangement.
  • Polythene, PVC, bakelite and melamine are examples.
  • Thermoplastics are plastics that distort quickly when heated and bend easily.
  • Some polymers, on the other hand, cannot be softened by heating after they have been formed once. Thermosetting plastics are what they’re termed.
  • Today, life would be unimaginable without plastics. Plastic is everywhere, whether indoors or outside.



(i) Non-reactive: Does not corrode or react to air, water, soil, many chemicals or other substances.

(ii) Light, strong, and long-lasting: Plastics can be moulded into a variety of shapes and sizes and used for various purposes.

(iii) Bad Conductors: They don’t let heat or electricity pass through them (wire covers and frying pan handle).


  • Plastic trash has a negative impact on the environment- it takes many years to decompose.
  • Poisonous fumes are released when plastics are burned- leading to air pollution.
  • They might take years to decompose in landfills for example. This is due to the fact that they are non-biodegradable.


  • We must employ synthetic fibres and plastics in such a way that we can enjoy their benefits while also lowering the environmental risks to living communities.
  • The 4 R principle: Reduce, Reuse, Recycle and Recover.
  • Practise segregation of biodegradable and non-biodegradable waste

Source: Chapter-3.pmd (


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