Class 8 Science

Synthetic Fibres

Types of Fibres

Natural Fibre: Fibres which are obtained from plants and animals are called natural fibres, e.g. cotton, wool, silk, jute, etc.

Synthetic Fibre: Fibres which are man-made are called synthetic fibres, e.g. nylon, acrylic, etc. A synthetic fibre is made of multiple units of a chemical substance. The units in a fibre are joined together like a chain.

Petrochemicals: Almost all synthetic fibres are made using raw materials from petroleum. Such raw materials which come from petroleum are called petrochemicals.

Polymer: A chain of a particular chemical substance is called a polymer. The individual unit in a polymer is called the monomer. Thus, a polymer is made up of many monomers. All synthetic fibres are polymers. Even cotton is a polymer.

Types of Synthetic Fibre

Rayon: Rayon was discovered towards the end of the nineteenth century. It was made by chemical treatment of wood pulp and was the first synthetic fibre.

  • Rayon is similar to silk but is cheaper than silk. Hence, rayon is also called ‘poor man’s silk’.
  • Rayon can be dyed in various colours.
  • Rayon is usually mixed with cotton to make bedsheet and dress materials.

Nylon: Nylon was made in 1931. The term ‘nylon’ has been derived from letters of ‘New York’ and ‘London’. No ingredient from plant or animal source was used in making nylon, as it is made from coal, water and air. Hence, nylon is called the first truly synthetic fibre.

  • Nylon is strong, light and elastic.
  • It is lustrous and easy to wash.
  • Nylon is used in many articles; like socks, bags, toothbrush, rope, sneakers, parachute, etc.
  • For the same thickness, a nylon thread is stronger than a steel wire.

Polyester: Polyester is made of repeating units of a chemical called ester.

  • Terylene is a popular polyester which is used in dress materials.
  • PET (Poly Ethylene Terephthalate) is another example of polyester. It is used for making bottles, utensils, films, wires and many other items.
  • Polyester fabrics do not wrinkle easily and are easy to wash.

Acrylic: Acrylic resembled wool and hence is also called synthetic wool. It is cheaper and more durable than wool, and is easier to wash and maintain.

Characteristics of Synthetic Fibres:

  • They are less expensive.
  • They are readily available.
  • They can be easily washed.
  • They are easy to maintain.