Corrosion Engineering Multiple Choice Questions on “Materials – Thermosetters”.
1. What is meant by thermosetting plastic?
a) It softens on heating and returns to original hardness on cooling
b) It hardens on heating and retains hardness on cooling
c) It hardens on heating and returns to original hardness on cooling
d) It softens on heating and retains hardness on cooling
Answer: b
Clarification: Plastics are readily divided into two types based on their thermal behavior. One is thermoplastic and another one is thermosetting. Thermosetting polymers are the polymers that harden on heating and retains hardness on cooling.
2. Which of the following is/are the example of thermosetting polymers?
a) Epoxies
b) Polyesters
c) Phenolics
d) Epoxies, polyesters, and phenolics
Answer: d
Clarification: Thermosetting polymers is one of the classifications of polymers based on the thermal behavior of polymers. Epoxies, polyesters, and phenolics are examples of thermosetting polymers.
3. Which of the following is/are the raw materials of Bakelite?
a) Phenol
b) Formaldehyde
c) Both phenol and formaldehyde
d) Neither phenol nor formaldehyde
Answer: c
Clarification: Bakelite is one of the most widely used thermosetting plastics for various domestic and industrial applications. Phenol or carbolic acid and formaldehyde are the raw materials of Bakelite.
4. Which of the following polyester is used in the space mirror satellite?
a) Mylar
b) Dacron
c) Vibrin
d) Dypol
Answer: a
Clarification: Thermosetting polymers such as Mylar, Dacron, Vibrin, and Dypol are categorize under polyester. The satellite was made of thin, reflective Mylar film.
5. Silicones are used for molding compounds, laminating resins, and insulation for electric motors and electronic equipment.
a) True
b) False
Answer: a
Clarification: Silicones are used for the molding compounds, laminating resins, and insulating for electric motors and electronic equipment because of its outstanding heat resistance. It can be demonstrated by Si–O–Si bond with alkyl groups on either side of the silicon atom.
6. What is the chemical name of the compound that is depicted in the given figure?
a) Formaldehyde
b) Bakelite
c) Urea
d) Vinyl chloride
Answer: c
Clarification: The compound that is depicted in the given figure is urea. It is one of the monomers of bauxite and beetle. It combines with formaldehyde to form plastics that used for the applications of kitchen dishware and utensils.
7. What is the abbreviation of FRP regarding reinforced plastics?
a) Filtrate-reinforced plastic
b) Fiber-reinforced plastic
c) Filter-reinforced plastic
d) Fume-reinforced polymer
Answer: b
Clarification: FRP can be abbreviated as Fiber-reinforced plastic regarding reinforced plastics. Carbon fibers, alumina fibers, an aramid fiber can be reinforced into plastics for better strength and corrosion resistance.
8. Which of the following thermosetting plastics that comes under phenolics?
a) Bakelite
b) Durez
c) Resinox
d) Bakelite, Durez, and Resinox
Answer: d
Clarification: Phenolics materials such as Bakelite, Durez, and Resinox are made up of phenol and formaldehyde. It uses for various applications such as electrical sockets, telephones, valves, and coatings.
9. Which of the following category that materials such as Epon, Durcon, and Araldite belong to?
a) Epoxies
b) Silicones
c) Phenolics
d) Polyesters
Answer: a
Clarification: Epon, Durcon, and Araldite belong to epoxies. These materials are the best combination of corrosion resistance and mechanical properties. It is mainly used as protective coatings, linings, and adhesives.
10. Which of the following is not a thermosetting plastic?
a) Dacron
b) Bakelite
c) Polystyrene
d) Polyester
Answer: c
Clarification: Thermosetting plastic is a plastic that hardens on heating and retains hardness on cooling. Dacron, Bakelite, and Polyester are examples of thermosetting plastics whereas Polystyrene is the example of thermoplastics.