Essay Answer Type Questions

ESSAY ANSWER TYPE QUESTIONS

On Polymers

1. What do you understand by polymerisation? With the help of suitable examples, compare and contrast the process of addition polymerisation and condensation polymerisation.

2. Define monomer and polymer. Write typical polymeric repeat unit structure for both addition and condensation polymerization. Which of the method is expected to result in branched structure? Explain.

3. (a) Describe the difference between thermoplastics and thermosetting plastics.

(b) Explain the difference between commodity plastics and engineering plastics.

4. Write an engineering brief about the following thermoplastics:

(I) Polyethylene,

(ii) Polyvinyl chloride,

 (iii) Acetal, and

 (iv) Polyimides.

5. List the properties and typical applications of the following thermoplastics:

(i) PTFE, (ii) PMMA, (iii) PET, and (iv) PEEK.

6. Tabulate the characteristics and typical applications of the following thermosetting plastics:

(i) Polyformaldehyde, and (ii) Urea formaldehyde

7. State, giving reasons for the choice, plastic materials that would be suitable for each of the following applications:

(a) cups for a machine dispensing cold drinks, 

(b) cups for a machine dispensing hot drinks,

(c) bottles to contain stiil water, and

(d) bottles to contain carbonated drinks.

8. Select suitable materials for the manufacture of the following, giving reasons for the choice:

(a) bottle crates,

(b) pipes and pipe fittings for the conveyance of domestic waste water,

(c) the casing of a domestic iron,

(d) the rear light lens cluster for an automobile, and

(e) the casing for an automobile door mirror.

On Engineering Ceramics

9. (a) What are ceramics? List and briefly explain five important properties of ceramics that make them useful engineering materials.

(b) What are the main classifications of ceramic materials?

10. Discuss the properties and typical applications of the following engineering ceramics:

(i) Al2O3,

(ii) SiC,.

(iii) Si+N4,

(iv) PSZ, and 

(v) Sialons.

On Composites

11. Explain the difference in strengthening mechanism between dispersion-strengthened and large-particle reinforced composites. 

12. (a) What is the distinction between matrix and dispersed phases in a composite material?

(b) Contrast the mechanical characteristics of matrix and dispersed phases for fibre-reinforced composites.

13. (a) Explain the strengthening mechanism of fibre-reinforced composites.

(b) Write short notes on : (i) SAP composites, and (ii) Cermets. 

(c) List the advantages, limitations, and applications of composite materials.