Thermoset

Q.

Which among the following is an example of thermosetting polymer?

1. Polyesters

2. Buna-S

3. Neoprene

4. Bakelite

Q.

Which of the following are characteristics of thermosetting polymers?

(a) Heavily branched cross linked polymers

(b) Linear slightly branched long chain molecules

(c) Become infusible on moulding so cannot be resused

(d) Soften on heating and harden on cooling, can be reused

Q.

Assertion (A) Network polymers are thermosetting.

Reason (R) Network polymers have high molecular mass.

(a) Assertion and Reason both are correct statement But reason does not explain Assertion.

(b) Assertion and Reason both are correct statement and Reason explains the Assertion.

(c) Both assertion and reason are wrong statements.

(d) Assertion is correct statement and Reason is wrong statement.

(e) Assertion is wrong statement and reason is correct statement.

Q. Thermosetting polymers are soluble in organic solvents

1. True
2. False

Q. _____ undergoes permanent deformation on heating.

1. Polythene
2. PVC
3. Teflon
4. Bakelite

Q. Polymers can be classified based on molecular forces.
(a) Classify the following polymers into elastomers and fibres:
Rubber, Nylon 6, 6, Buna-S, Terylene
(b) What do you mean by thermosetting polymers? Give one example.

Q. Which of the following is a thermosetting polymer?

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1. Bakelite
2. Buna-N
3. PVC
4. Nylon 6

Q. A. Bakelite is a thermosetting polymer.
R. It can be melted again and again without any change.

1. Both A and R are correct and R is the correct explanation of the A
2. A is correct but R is incorrect
3. Both A and R are correct but R is not the correct explanation of the A
4. A is incorrect but R is correct

Q. Why can't thermosetting polymers be reused after getting moulded?

1. They become soft at high temperatures and melt.
2. They form crosslinks at high temperatures which make them hard and strong
3. They become brittle at high temperatures
4. They cannot be heated as they are very good conductors of heat.

Q. Why can't thermosetting polymers be reused after getting moulded?

1. They become soft at high temperatures and melt.
2. They form crosslinks at high temperatures which make them hard and strong
3. They become brittle at high temperatures
4. They cannot be heated as they are very good conductors of heat.

Q. What are the thermosetting polymers?

Q. Thermosetting polymers are soluble in organic solvents

1. True
2. False

Q. Why is teflon used in non-stick cookwares ?
(SURFACE CHEMISTRY)

Q. Which of the following is an example of thermosetting polymer ?

1. Sealing Wax
2. Nylon - $6,6$
3. PVC
4. Bakelite

Q. Which of the following are characteristics of thermosetting polymers?

1. Heavily branched cross-linked polymers
2. Linear or slightly branched long chain molecules
3. Become infusible on moulding so cannot be reused
4. Soften on heating and harden on cooling, can be reused.

Q. Three dimensional molecules with cross links are formed in the case of a:

1. thermoplastic
2. thermosetting plastic
3. None of the above
4. both $A$ & $B$

Q. Which one of these are incorrect for thermosetting polymers?

1. They are not reusable after heating.
2. On heating undergo extensive cross linking in moulds and become infusible.
3. They are reusable.
4. They are cross linked.

Q. Assertion : Bakelite is a thermosetting polymer.
Reason : Bakelite can be melted again and again without any change.

1. If both assertion and reason are true but reason is not the correct explanation of the assertion.
2. If assertion is true but reason is false.
3. If both assertion and reason are true and the reason is the correct explanation of the assertion.
4. If assertion is false but reason is true.