This set of Applied Chemistry Question Bank focuses on “Compounding of Plastics – 2”.
1. In compression moulding, the cavity is filled with ________ plastic.
d) May be solid or liquid
Explanation: The top and bottom moulds are capable of moving relatively. When heat and pressure is applied according to the specification, the fluidized plastic is filled in the cavity.
2. Curing means the time given to the polymer for setting.
Explanation: Curing means the time given to the polymer for setting in the mould. It is done either by heating in case of thermo plastic resins.
3. The cost of production for the injection moulding is ___________
d) Very high
Explanation: Th cost of the production for the injection moulding is low. It has high speed production. Loss of the materials will be less.
4. Which of the following is the part of the injection moulding device?
b) Guide pins
c) Top mould
d) Bottom mould
Explanation: The regulator I used in the injection moulding device. The guide pins, top mould and bottom moulds are used in the compressing moulding of plastics.
5. In transfer moulding the powdered compounded plastic is in the chamber which is applied __________ temperature and ________ pressure.
a) High, low
b) Low, high
c) Minimum, high
d) Maximum, high
Explanation: In transfer moulding the powdered compounded plastic is in the chamber which is applied minimum temperature and high pressure.
6. The soft and semi solid plastic is injected into mould by _________
Explanation: Plunger is used to inject the soft and semi solid plastic to work at high pressure due to the high friction at nozzle.
7. Very delicate and intricate shapes can be produced in transfer moulding due to ___________
a) Plasticized mix flows very fast into mould
b) Plasticized mix flows very slow into the mould
c) High pressure
d) Minimum temperature
Explanation: Very delicate and intricate shapes can be produced in transfer moulding due to plasticized mix flows very slow into the mould. The mould is heating up to the curing temperature and allowed to set.
8. A hot, softened thermo plastic tube is called as _____________
a) Extruded tube
Explanation: A hot, softened thermo plastic tube is called parison is placed inside a two piece hollow tube in the mould. It is used in the blowing technique.
9. The article in the transfer moulding are __________
a) Cured very fast
b) Cured incompletely
c) Cured uniformly
d) Cured moderately
Explanation: The article in the transfer moulding are cured uniformly. They are cured slowly and completely. The articles are free from flow marks and thick pieces.
10. Extrusion moulding is for __________
a) Thermo plastic resins
b) Thermo setting resins
c) Both thermo plastic and thermo setting resins
d) Neither thermo plastic nor thermo setting resins
Explanation: Extrusion moulding is the method that is applied to the thermo plastic resins to make articles of uniform cross section like tubes, rods, sheets etc.
11. Blowing otherwise called as _________
a) Air blow technique
c) Bubble casting
d) Bubble blowing
Explanation: Blowing otherwise called as the bubble casting. It is used for the fabricating hollow plastic articles like soft drink bottles etc.
12. Thermo forming technique is used for fabricating __________
a) Hollow plastic articles
b) Plastic tubes
c) Plastic wires
d) Three dimensional articles
Explanation: Thermo forming technique is used for fabricating the three dimensional articles. The tubes and wires are fabricated by the extrusion moulding and hollow plastic articles by thermo forming.
13. Thermo forming method is a combination of __________ and __________
a) Blowing, extrusion moulding
b) Blowing, compression moulding
c) Extrusion moulding, compression moulding
d) Transfer moulding, blowing
Explanation: The thermoforming method is a combination of the extrusion moulding and compression moulding.
14. Blistering is almost eliminated in the __________
a) Transfer moulding
c) Extrusion moulding
d) Injection moulding
Explanation: Blistering is almost eliminated in the transfer moulding. It is one of the advantages of the transfer moulding.
15. Which of the following is not the part of the transfer moulding device?
Explanation: The hinge, plunger and orifice are present in the transfer moulding. The soft plastic is injected by plunger, ejected from orifice and spreader is present in the injection moulding.
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