Engineering Chemistry

Polymer Viva Questions

Polymer Viva Questions

Polymer Viva Questions, Short Answer Questions on Polymer, Viva Questions on Polymer, Engineering Chemistry Viva Questions, polymers questions and answers, polymers exam questions, polymers important questions, polymer question bank, multiple-choice questions on polymers with answers, polymer MCQ for gate, polymer interview questions, polymer chemistry quiz questions, Polymer Viva Questions

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Short Answer Questions

Q.1. What is a monomer?

Ans. The repeating unit present in the formation of a polymer is known as a monomer.

Q.2. What is a polymer?

Ans. Polymers are macromolecules of high molecular masses built up by linking together a large number of small, repeated units by a covalent bond.

Q.3. What is meant by polymerisation?

Ans. The chemical process leading to the formation of a polymer is known as polymerisation.

Q.4. What is meant by the degree of polymerisation?

Ans. The number of monomer units in a polymer is known as the degree of polymerisation.

Q.5. Differentiate between homopolymer and copolymer.

Ans. Homopolymers are formed with the same monomer units. For example, PE, PS, PVC, etc.

Copolymers are formed with two or more different monomers. For example, styrene-butadiene rubber (styrene + butadiene).

Q.6. Differentiate between addition and condensation polymerisation.

Ans. Addition polymerisation is the process of polymerisation by the addition of monomer units that have unsaturated double or triple bonds. For example, polyethylene, polyvinyl chloride, etc.

Condensation polymerisation takes place where the monomer units have two or more reactive functional groups. For example, polyester, nylon, polyamide, etc.

Q.7. Define thermoplastics.

Ans. Linear, long-chain polymers which can be softened on heating and hardened on cooling are known as thermoplastics. For example, polythene, polyvinyl chloride, etc.

Q.8. What are the monomers present on nylon 66?

Ans. Hexamethylenediamine and adipic acid.

Q.9. What is meant by the vulcanisation of rubber?

Ans. Vulcanisation is heating of the raw rubber at 100–140°C with sulphur.

Q.10. What is natural rubber?

Ans. Cis-polyisoprene is natural rubber.

Q.11. What is gutta-percha?

Ans. Trans-polyisoprene is gutta-percha.

Q.12. What is crepe rubber?

Ans. Rubber with sodium bisulphite is passed through a creping machine and the coagulum is rolled into sheets. The sheet is hence having a surface like a crepe paper; hence, it is known as crepe rubber.

Q.13. What is an elastomer?

Ans. An elastomer is vulcanisable rubber-like polymer, which can be stretched to at least twice its length and returned to its original shape and dimensions as soon as stretching force is released.

Q.14. Why does raw rubber need vulcanisation?

Ans. In vulcanisation, sulphur combines chemically at the double bonds of different rubber springs and provides cross-linking between the chains. Hence, stiffening the rubber needs vulcanisation.

Q.15. Give examples for natural polymers.

Ans. Cotton, silk, wool, nucleic acid, proteins, starch, cellulose, etc.

Q.16. Give examples for inorganic polymers.

Ans. Polyphosphazenes, polysilanes, polygermanes, etc.

Q.17. What are the substances mixed in the compounding of rubber?

Ans. Antioxidants, colouring agents, vulcanising agents, accelerators, plasticisers and inert fillers are added in the compounding of raw rubber.

Q.18. Give a note on Bio-polymers?

Ans. Biopolymers are macromolecules that occur in nature from plants, trees, bacteria, algae or other sources that are long chains linked together through a chemical bond. They are often degradable through a microbial processes such as compositing. For example, cellulose, proteins, starch, collagen, casein and polyesters.

Q.19. Write important bio-degradable polymers?

Ans.

  • Lactic acids: It is obtained from fermentation of sugar feed stocks conversion of starch from corn, potato peels, etc.
  • Triglycerides: It is produced from soya bean, fax and rape seed.
  • Starch: It is found in corn, potatoes, wheat, tapioca and some other plants.
  • Collagen: It is found in mammals. It is used in capsules for drug.

Q.20. Explain the importance of biopolymers?

Ans. Bio-based materials have the potential to produce fewer greenhouses gases, require less energy and produce fewer toxic pollutants.

  • They may also be recyclable or composted.
  • They reduce waste stream.

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