__________ moulding is used for shaping of thermosetting plastics exclusively.

__________ moulding process can not be used for thermoplastic plastics.

A

Compression

B

Extrusion

C

Injection

D

None of these

__________ is a thermosetting plastic.

A

Polyvinyl chloride

B

Polythene

C

Bakelite

D

Teflon

Most of the plastics are safe to be used upto a maximum temperature of __________ °C.

A

100

B

150

C

350

D

450

Which of the following is a thermosetting polymer?

A

PVC

B

PTFE

C

Nylon

D

Polyesters

Which of the following is an example of thermosetting plastic?

A

Bakelite

B

PVC

C

Polyethylene

D

No option is correct.

The thermosetting plastic

A

Becomes rigid when moulded at suitable pressure and temperature

B

At 127°C to 177°C permanently set and further application of heat does not soften it

C

Chars at 343°C

D

All the above

Thermosetting materials

A

Are cross-linked molecules

B

Soften on application of heat

C

Are solvent soluble

D

None of these

Polymers are classified into four categories namely thermosetting, thermoplastic, elastomer and fibre depending upon their

A

Molecular sizes

B

Magnitude of intermolecular forces

C

Resistance to heat

D

Polymerisation mechanism

Thermosetting resins/polymers as compared to thermoplastic ones are

A

Soluble in all organic solvents

B

More brittle

C

Formed by addition polymerisation only

D

Easily reshaped & reused

Thermosetting polymers as compared to thermoplastic polymers

A

Are formed by addition polymerisation

B

Have three dimensional structure

C

Have linear structure

D

None of these

__________ moulding is used for shaping of thermosetting plastics exclusively.

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