* Activity - 1(ch-3) Synthetic fibres of plastic
(characteristics of diferent
Syntetic fibres
from daily life
1. Find out the characteristic of different
Synthetic fibres used in daily life
Categories them according to their properties
Procedure:
1- Collect at least lo different types of
Synthetic fibres used in household work
in day to day life.
1. Find out their physical characteristics
and entist them in tabular form.
3. on the basis of their properties categories
Them and try to find out the type of
Synthetic fibre
4. Write their use in daily life.
Answers
Answer:
A synthetic fibre is also 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 polymer. The
word ‘polymer’ comes from two Greek
words; poly meaning many and mer
meaning part/unit. So, a polymer is made
of many repeating units.
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Polymers occur in nature also. Cotton,
for example, is a polymer called
cellulose. Cellulose is made up of a
large number of glucose units.
3.2 Types of Synthetic Fibres
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. (Fig. 3.2.)
Nylon
Nylon is another man-made fibre. In
1931, it was made without using any
natural raw material (from plant or
animal). It was prepared from coal, water
and air. It was the first fully synthetic
fibre.
Nylon fibre was strong, elastic and
light. It was lustrous and easy to wash.
So, it became very popular for making
clothes.
We use many articles made from
nylon, such as socks, ropes, tents,
toothbrushes, car seat belts, sleeping
bags, curtains, etc. (Fig. 3.3). Nylon is
SYNTHETIC FIBRES AND PLASTICS 33
Fig. 3.2 : Articles made of rayon
Fig. 3.3: Various articles made from nylon
Is nylon fibre
really so strong
that we can make
nylon parachutes
and ropes for rock
climbing?
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Explanation: