Related Questions

Melt spinning of polymers involves the forcing of polymer melt through spinnerettes (fine holes) into an atmosphere kept at a temperature lower than the melting point of the polymer, which causes the fine diameter polymer melt to harden into filaments. Melt spinning is not used in case of the __________ fibres.
A Acrylic
B Polyester
C Nylon 6:6
D Polypropylene
In a cross linked polymer, the monomeric units are linked together to constitute a three dimensional network. Which of the following is a cross-linked polymer?
A Bakelite (phenol formaldehyde)
B Polyester
C Polythene
D Nylon-6
In case of dry spinning of polymers, the polymer solution in a volatile solvent is forced through the spinnerates into a warm air chamber, where the solvent evaporates leaving behind the polymer in the filament form. Dry spinning is used for __________ fibres.
A Polythene
B PVC
C Rayon
D Polyvinyl acetate
Which of the following is an example of thermosetting plastic?
A Bakelite
B PVC
C Polyethylene
D No option is correct.
Thermosetting resins are those polymers, which
A Do not increase in plasticity with rise in temperature
B Allow slip to occur between molecules
C Do not take on a permanent set
D None of these
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
__________ is a thermosetting plastic.
A Polyvinyl chloride
B Polythene
C Bakelite
D Teflon
Thermosetting materials
A Are cross-linked molecules
B Soften on application of heat
C Are solvent soluble
D None of these
__________ moulding is used for shaping of thermosetting plastics exclusively.
A Compression
B Injection
C Transfer
D Extrusion
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

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