SYNTHETIC FIBRES AND PLASTICS
Introduction
The clothes which we wear are made of fabrics. Fabrics are made from fibres obtained from natural or artificial sources.
EX- natural fibres- Obtained from plants:Wool, silk, cotton,synthetic fibres-made by human beings: polyesters,terylene
What are Synthetic Fibres?
- A synthetic fibre is a chain of small units joined together.
- Each small unit is actually a chemical substance.
- Many such small units combine to form a large single unit called a
RAYON (also called artificial silk )
- It is cheaper than silk and can be woven like silk fibres.
- It is made from cellulose obtained from wood pulp.
- It can also be dyed in a wide variety of colours.
- It is used to make carpets , bed sheets
Nylon
- It is prepared from coal, water and air.
- It was the first fully synthetic fibre.
- Nylon fibre is strong, elastic and light.
- It is lustrous and easy to wash.
- It is used to make socks, ropes, tents, toothbrushes, car seat belts, sleeping bags, curtains, parachutes and ropes for rock climbing .
POLYSTER
- A versatile man-made fabric.
- It has an outstanding characteristic of resisting wrinkle.
- It is strong and soft.
- Ex: Terylene
- It is used in dresses, suits, rainwear
- PET (polyethylene terephthalate) is a very familiar form of polyester.
- It is used for making bottles, utensils, films, wires and many other useful products.
ACRYLIC
- A fibre similar to that of wool and is used to make sweater, blankets, shawls, etc.
- It is lightweight, soft and warm.
- It is cheaper than natural wool.
- It is resistant to chemicals, moths and sunlight.
Characteristics of Synthetic Fibres
- They are durable
- They dry up quickly
- They are less expensive
- They are readily available
- They are easy to maintain.
Plastics
- Like synthetic fibres, 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.
- Plastic is easily mouldable i.e. can be shaped in any form.
- Plastic can be recycled, reused, coloured, melted, rolled into sheets or made into wires.
Thermoplastics
plastic which gets deformed easily on heating and can be bent easily.
Ex:Polythene and PVC
Uses: manufacturing toys, combs and various types of containers
Fig: Thermoplastic
Thermosetting plastics
plastics which when moulded once, can not be softened by heating.
Ex:bakelite and melamine.
Bakelite is a poor conductor of heat and electricity.
- It is used for making electrical switches, handles of various utensils, etc.
- Melamine is a versatile material.
- It resists fire and can tolerate heat better than other plastics
- It is used for making floor tiles, kitchenware and fabrics which resist fire
