Synthetic Fibers and Plastics || class 8th notes|| ncert science notes

on

 Synthetic Fibers and Plastics



  • Synthetic fibers and Plastics, like natural fibers, are made of very large units called polymers. Polymers are made up of many smaller units. Polymers are made up of smaller units.
  • While natural fibers are made up of many smaller units. Polymers are made up of many smaller units.
  • While natural fibers are obtained from plants and animals, synthetic fibers are obtained by chemical processing of petrochemicals. Like natural fibers, these fibers can also be woven into fabrics.
  • synthetic fibers find uses ranging from many household articles like ropes, buckets, furniture, containers, etc. to highly specialized uses in aircrafts, ships, spacecrafts, healthcare, etc.
  • Depending upon the types of chemicals used for manufacturing synthetic fibers, they are named as Rayon, Nylon, Polyester and Acrylic.
  • The different types of fibers differ from one another in their strength, water absorbing capacity, nature of burning, cost, durability, etc.
  • Today, life without plastics cannot be imagined. be it home, or outside, plastic is everywhere.
  • The waste created by plastics is not environment friendly. One burning plastic release poisonous gas. On dumping in the ground, they may take years to regenerate. this is because of their non-biodegradable nature.
  • We need to use synthetic fibers and plastics in such a manner that we can enjoy their good qualities and at the same time minimize the environmental hazards for the living communities.

TYPES OF SYNTHETIC FIBERS:

  1. Rayon:  It is made from cellulose obtained from wood pulp. It is used to make containers, car upholstery, etc.
  2. Nylon: A polyamide made from petroleum. It is lightweight, strong and durable. The fabric allows easy evaporation and dries quickly. It is used in parachutes, flak vest, combat uniforms, tires, etc.
  3. Polyester: A versatile and important man-made fabric. It has an outstanding characteristic of resisting wrinkle and springing back into its crisp, smooth shape. It is strong and soft. It is used in dresses, suits, rainwear, etc.
  4. Acrylic: A fiber similar to that of wool and is used to make sweater, blankets, shawls, etc. It is lightweight, soft and warm. Also, it is cheaper than natural wool. It is resistant to chemicals, moths and sunlight. Therefore, they are widely in use nowadays.
  5. Plastics:  like synthetic fibers, plastic is also a polymer. Some plastics have a linear arrangement of the units, and some have a cross-linked arrangement of the units. Example: Polythene.
CHARACTERISTICS OF PLASTICS:
  • Non- reactive: Not affected by air, water, soil, etc.
  • Light, Strong and Durable: Light, strong and durable and can be molded into different shapes and sizes.
  • Poor Conductors: Do not allow heat and electricity to flow through them.
Effect of Plastics on Environment: Natural materials like wood and paper are biodegradable (bio=living; degradable= able to be broken down). In contrast, most plastics do not decay, therefore, they are non-biodegradable. The lightweight nature of plastics can also be a problem. Burning of plastics also release poisonous fumes into the atmosphere. this way plastics pollute the environment.

Comments

Post a Comment