Synthetic Fibres and Plastics
Chapter-3
Activity - 1
Objective
To compare the water absorption capacity of fabrics made from
syntheticfibres and natural fibres.
Required material : Cotton cloth and nylon cloth of same size, two buckets, water,
measuring cylinder etc.
Process : 1. Take two buckets and fill them with equal amount of water.
2. Soak cotton cloth and nylon cloth in these buckets separately for 10
minutes.
3. Take the clothes out of buckets.
4. Take the water that remains in buckets in a measuring cylinder one by
one and measure watervolume.
5. Observe which fabric absorbs more amount of water.
Deepak Printers & Pubillah, Haldwani
Observation Table
teacher
S.No.
Bucket
Type of cloth
Water remaining in
the bucket (ml)
OM
Bucket A
Cotton
bacteria
2.
Bucket B
Nylon
Answers
Explanation:
Question 1:
Which of these is a natural fibre?
(a) rayon
(b) cotton
(c) nylon
(d) polyester
ANSWER:
(b) cotton
Natural fibres are greatly elongated hair-like substances obtained from plants or animals. They can be spun into filaments, threads or ropes. Cotton fibre is almost pure cellulose that grows in a protective capsule around the seeds of cotton plants.
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Question 2:
Which of these is a fibre derived from chemicals?
(a) rayon
(b) cotton
(c) nylon
(d) silk
ANSWER:
(c) nylon
Fibres derived from chemicals are polymers. They do not occur naturally but are produced entirely in chemical plants or laboratories. Nylons are man-made polymer fibres.
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Question 3:
Which of these fibres is made from a raw material obtained from plants?
(a) rayon
(b) nylon
(c) terylene
(d) polyester
ANSWER:
(a) rayon
Rayon is a manufactured regenerated cellulose fibre that is made from purified cellulose, primarily from wood pulp.
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Question 4:
Which of these is a thermosetting plastic?
(a) polystyrene
(b) bakelite
(c) polythene
(d) polyvinyl chloride
ANSWER:
(b) bakelite
Thermosetting plastics are rigid and heavily cross-linked polymers. They cannot be remoulded once they set. Bakelite is a thermosetting phenol formaldehyde resin.
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Question 5:
Which of these plastics is a polymer?
(a) bakelite
(b) polystyrene
(c) polythene
(d) all of these
ANSWER:
(d) all of these
A polymer is a macromolecule composed of many repeated subunits, known as monomers. Bakelite is a phenol formaldehyde resin. Polystyrene is a synthetic aromatic polymer made from the styrene monomer. Polythene is a thermoplastic polymer consisting of long hydrocarbon chains.
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Question 6:
Which of these plastics can be repeatedly heated and moulded into any desired shape?
(a) bakelite
(b) polythene
(c) formica
(d) melamine
ANSWER:
(b) polythene
Polythene is a thermoplastic polymer consisting of long hydrocarbon chains. Thermoplastic polymers can be repeatedly heated and moulded into any desired shape.
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Question 7:
Which of these can you use as a substitute for glass in windows?
(a) polythene
(b) PVC
(c) perspex
(d) teflon
ANSWER:
(c) perspex
Perspex is a thermoplastic. It is transparent like glass but it is much stronger. It is used as a substitute for glass in windows.
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Question 8:
Which of these is not a property of plastics?
(a) bad conductor of heat
(b) bad conductor of electricity
(c) inflammable
(d) soluble in water
ANSWER:
(d) soluble in water
Plastics are insoluble in water. That is why plastic buckets are used to store water and plastic glasses are used to drink water.