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Chapter 3 : Synthetic Fibres And Plastics
The clothes which we wear are made of fabrics. Fabrics are made from fibres obtained from natural or artificial sources. Can you name some natural fibres? Fibres are also used for making a large variety of household articles. Make a list of some common articles made from fibres. Try to separate them into those made from natural fibres and those made from artificial fibres.
3.1 What Are Synthetic Fibres?
Try to recall the uniform pattern found in a necklace of beads joined with the help of a thread [Fig. 3.1(a)]. Or, try to join a number of paper clips together to make a long chain, as in Fig. 3.1 (b). Is there any similarity between the two?
3.2 Types Of Synthetic Fibres
A. Rayon
You have read in Class VII that silk fibre
obtained from silkworm was discovered
in China and was kept as a closely
guarded secret for a long time. Fabric
obtained from silk fibre was very costly.
But its beautiful texture fascinated
everybody. Attempts were made to make
silk artificially. Towards the end of the
nineteenth century, scientists were
successful in obtaining a fibre having
properties similar to that of silk. Such a
fibre was obtained by chemical
treatment of wood pulp. This fibre was
called rayon or artificial silk. Although
rayon is obtained from a natural source,
wood pulp, yet it is a man-made fibre. It
is cheaper than silk and can be woven
like silk fibres. It can also be dyed in a
wide variety of colours. Rayon is mixed
with cotton to make bed sheets or mixed
with wool to make carpets.
3.3 Characteristics Of Synthetic Fibres
Imagine that it is a rainy day. What kind of umbrella would you use and why? Synthetic fibres possess unique characteristics which make them popular dress materials. They dry up quickly, are durable, less expensive, readily available and easy to maintain. Perform the following activity and learn for yourself.
3.4 Plastics
You must be familiar with many plastic
articles used everyday. Make a list of
such items and their uses.
Plastic is also a polymer like the
synthetic fibre. All plastics do not
have the same type of arrangement of
units. In some it is linear, whereas in
others it is cross-linked.
3.5 Plastics As Materials Of Choice
Today if we think of storing a food item, water, milk, pickles, dry food, etc., plastic containers seem most convenient. This is because of their light weight, lower price, good strength and easy handling. Being lighter as compared to metals, plastics are used in cars, aircrafts and spacecrafts, too. The list is endless if we start counting articles like slippers, furniture and decoration pieces, etc.
3.7 Plastics And The Environment
When we go to the market, we get usually things wrapped in plastic or packed in polythene bags. That is one reason why plastic waste keeps getting accumulated in our homes. Ultimately, plastic finds its way in the garbage. Disposal of plastic is a major problem. Why?
