Question

0.1 Multiple choice questions:
a) Which of the following is an example of thermosetting plastics?
(i) Nylon (ii) Polythene. (iii) PVC. (iv) Bakelite
b) Which of the following synthetic fibres has a feel similar to wool?
(i) Nylon (ii) Polyester. (iii) Acrylic. (iv). Rayon
c) Which of the following is called artificial silk?
(1) Polyester. (ii) Rayon. (iii) Nylon. (iv) Acrylic
0.2 Fill in the blanks:
a)
Plastics do not soften on heating and cannot be reshaped.
b) The best way to dispose the discarded plastic is
c) The Plastic which is used as a substitute for glass is
is known as Thermocol.
0.3 Answer the following questions:
a) How many types of Plastics are there?
b) Name three types of synthetic fibres.​

Answer 1

0.1. a) polythene. b) acrylic. c)rayon

Answer 2

Answer:

0.1 a)Bakelite    b)Acrylic    c)Rayon

0.2 a)Thermoplastic   b)Recycling  c)PMMA (Polymethyl methacrylate)  

      d)Styrofoam

0.3 a)There are two main types of plastic: Thermoplastic and Thermosets

      b)Rayon, Nylon,  and Polyester are three types of synthetic fiber.

Explanation:

0.1

a)Bakelite is an example of thermosetting plastic others are belong to the class of thermoplastics.

• Since this polymer has a low electrical conductivity and high heat resistance, it is widely used in electrical switches.

b)Acrylic fiber is more prevalent than natural wool.

• The clothes prepared from acrylic fiber are cheaper and more durable.

c)Rayon, also known as artificial silk, is a synthetic fiber, made from regenerated cellulose.

0.2

a)Thermosetting plastics such as Bakelite, Melamine do not undergo softening and cannot be reshaped once it is molded.

• Thermosetting plastics are commonly used in electrical appliances.

b)Recycling is the best way to discard plastic waste.

• If they are not recycled at the proper time, then they get mixed with other chemicals and hence become more difficult to recycle and become a source of pollution.

c)Polymethyl methacrylate is a transparent thermoplastic polymer.

• It is often used as a substitute for glass.

d)Polystyrene is used to make disposal plastic-like thermocol.

• Thermocol, alternatively known as Styrofoam, is one of the widely used products that are primarily used to manufacture things such as disposable trays, packaging materials, containers, etc.

0.3 a) Plastics are divided into two types

  1. Thermoplastic-Plastics that can be deformed easily upon heating and can be bent easily.

• Examples are PVC, polythene, Nylon, Polystyrene, etc.

   2. Thermosetting - Plastics that cannot be softened again by heating once they are molded.

• Examples are Bakelite, Melamine, Urea-formaldehyde,  etc.

• b) Synthetic fibers are man-made fibers produced from chemical substances are used for making clothes and other useful things.

Synthetic fibers are of four types: Rayon, Nylon, Polyester, Acrylic.