281. Filler is used in plastics to
A.Completely fill up the voids created during manufacturing
B.Improve plasticity, strength and toughness
C.Provide colour, strength, impact and resistance and reduce cost
D.To accelerate the condensation and polymerisation
282. Which of the following moulding methods is generally not used for thermoplastic materials
A.Extrusion
B.Injection
C.Casting
D.Calendering
283. Hypo-eutectoid steels for hardening purposes are heated by 30-50°C
A.Above lower critical temperature
B.Below lower critical temperature
C.Below upper critical temperature
D.Above upper critical temperature
284. The moulding process employed for thermoplastic material is
A.Injection and extrusion methods
B.Compression and transfer moulding methods
C.Similar to thermosetting plastics except that higher temperature is used
D.Similar to thermosetting plastics except that a lower temperature is used
285. Pigments are fine, solid particles used in preparation of
A.Varnishes
B.Plastics
C.Chemicals
D.Paints
286. One of the main disadvantage of thermosetting and thermoplastic plastics is that
A.They deform under heat and pressure
B.They are resistant to water upto 100°C only
C.They do not possess a high mechanical strength
D.Their shape cannot be changed without application of heat
287. Polyesters belong to the group of
A.Thermoplastic plastics
B.Thermosetting plastics
C.Phenolics
D.PVC
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