JNTU Previous Exams Papers Polymeric Materials Apr-May 2008

JNTU B.Tech II Semester Examinations, POLYMERIC MATERIALS, Apr/May 2008

(Metallurgy & Material Technology)

Time: 3 hours Max Marks: 80

SET-IV

Answer any FIVE Questions

All Questions carry equal marks

 

1. (a) List out the methods of polymerization of thermoplastic materials. Explain any one method of polymerization.

(b) What is calendaring? Explain. [10+6]

 

2. What is the basis for the classification of microstructures of the polymers? Explain with examples. [16]

 

3. (a) What finishing operations are needed on a part which is transfer molded? Explain.

(b) What causes the plastic to move through the extrusion machine? Explain with diagram. [8+8]

 

4. (a) What is polymer degradation? Explain the classification of degradation processes in polymers.

(b) What is thermal degradation? Explain the factors affecting the thermal degradation of polymers. [8+8]

 

5. (a) With the help of a flow chart explain the manufacture of low density polyethylene.

(b) Describe the relation between long chain branching and molecular weight distribution, typical to low density polyethylene.

(c) Explain why is polyvinylchloride scrap is reuseable while bakelite scrap is useless. [7+5+4]

 

6. (a) Discuss the kinetics of condensation polymerization.

(b) In what way transfer molding equipement differ from compression molding process. Discuss. [8+8]

 

7. (a) Explain how Cellulose accetate is produced.

(b) Give the structure and chemical reactions involved during the formulation of

Cellulose accetate. [8+8]

 

8. (a) Explain tubing technique of fabrication of rubber in detail.

(b) Can styrene-butadiene rubber (SBR) be vulcanized. Explain.

(c) What are some advantages and disadvantages of SBR? [8+4+4]

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