Question

Plastics that retain their plasticity on repeated heating are called
(a) thermosetting plastics
(b) thermoplastics
(c) thermal plastics
(d) none of these

Answer 1

Explanation:

Explain why some fabrics are called synthetics.

Ans. Some fabrics do not occur in the nature are hence called synthetic fibres.

2. Rayon is different from synthetic fibres because:

• It has a silk like appearance.

• It is obtained from wood pulp.

• Its fibres can also be woven like those of natural fibres.

• It is obtained from wood pulp.

Ans. It is obtained from wood pulp

3. Fill in the blanks with appropriate word:

a) Synthetic fibres are also called man-made or artificial fibres.

b) Synthetic fibres are synthesized from raw-materials called petrochemicals.

c) Like synthic fibres, plastic is also a polymer.

4. Give examples which indicate that nylon fibres are very strong.

Answer 2

option ( a)

The use of thermoset plastics has a number of advantages. Unlike thermoplastics, they retain their strength and shape even when heated. This makes thermosetting plastics well-suited to the production of permanent components and large, solid shapes