Back to Lesson

• Fibre: String made of some material
• Natural fibre: Obtained from plants and animals. E.g. Cotton, Wool, Silk
• Synthetic fibre: Artificially made fibres through chemical treatments. E.g: Rayon, Nylon, Polyester and Acrylic. It is made up of small chemical units joined repeatedly to form polymer [poly- many, mer- units].
• Properties of synthetic fibres:
  • Durable
  • Less expensive
  • Readily available
  • Easy maintenance
  • Dry up quickly
  • On heating these fibres melts
• Types, properties and uses of synthetic fibres:
  

  	Rayon (Artificial silk)	Nylon	Polyester	Acrylic
  Made from	Wood pulp	Coal, water and air	Repeated units of chemical	Polymer made of repeated units of chemical
  Properties	Cheaper than silk Can be woven like silk fibres Colored similar to silk fibres using dye	High strength High elasticity Lighter as compared to other fibres	Do not form folds Easy to wash Can be woven like any other thread	Similar to wool Cheaper than wool Available in variety of colors
  Uses	Mixed with cotton Mixed with wool to make carpets	Articles like socks, ropes, tents, toothbrushes, curtains, seat belts in cars, parachute, etc.	Polyester: Dress material. PET: Bottles films, utensils, wires, etc.	Use to make sweaters, shawls, blankets, etc.

Click here to watch video on Types Of Synthetic Fibres

• Plastic:
  • Plastic is polymer having repeated chemical units.
  • In plastics units are joined in linear or grid fashion. Plastics are moldable, by application heat and pressure plastic are converted to variety of shapes and sizes.
  • Plastics are easy to color an can be rolled into sheets and wires
  • Reuse: Same plastic articles can be used for different purposes. E.g. Plastic bottle can be used for planting small plants.
  • Recycle: Old plastic articles are converted to new materials by the application of heat and pressure.
  • Plastics are of two types thermoplastic and thermosetting plastics.
  • Comparison between thermoplastic and thermosetting plastic

  Thermoplastic	Thermosetting plastic
  Plastic changes shape on heating	Plastic does not change shape on heating
  Polythene and PVC are thermoplastic	Bakelite and Melamine are Thermosetting plastic
  Thermoplastic can be moulded again and again by application of heat and pressure.	Cannot be moulded again and again
  Used for making toys, combs, containers, etc.	Used for making kitchen wares, electrical switches, fabrics, etc

• Properties of plastics:
  • Plastic is non reactive: Plastic is non reactive hence, it used to store chemicals and various material
  • Plastic is light, strong, durable: Plastic is lighter than metals, not so strong but is efficient for use, has longer duration.
  • Plastic is poor conductor of heat and electricity: Do not conduct heat and electricity, hence is used in handles for kitchen wares, screwdrivers, etc.
• Environment and plastic:
  • Biodegradable waste: Waste that are decomposed in small time interval is called biodegradable waste. E.g. Fruits and vegetables leftover, paper, wood, cotton cloth, etc.
  • Non biodegradable waste: Waste which takes long time to decompose is called non biodegradable waste. E.g. Metallic waste and Plastic bags.
  • Effect of plastic on environment: Plastics pollute environment. Plastics when burnt produces poisonous gas which is again harmful for living organisms.
  • Reduction of pollution from plastic:
    • Use of jute bags or paper bags instead of plastic bags.
    • Proper disposal method of plastics
    • Recycling and reusing plastic materials.