LOYOLA COLLEGE (AUTONOMOUS), CHENNAI –600 034

B.Sc., DEGREE EXAMINATION – CHEMISTRY

FIFTH SEMESTER – NOVEMBER 2003

CH – 5400/CHE400/CH518 – POLYMER CHEMISTRY

07.11.2003                                                                                                          Max:100 marks

1.00 – 4.00

 

PART-A

 

Answer all the questions.                                                                                 (10×2=20 marks)

 

1. What are chain transfer agents? Give an example.
2. What are plasticizers? Give an example.
3. Define CMC.
4. Mention two disadvantages of bulk polymerization.
5. When rubber is masticated in an atmosphere of nitrogen, the degradation does not occur, but when the process is repeated in the presence of air, the degradation is very quick and significant – Explain.
6. Mention the polymer used for the following:

• Articles that can be sterilized.
• Attractive sign boards and durable lenses.

7. What are Kevlar fibres?
8. What is compounding?
9. Mention the uses of FRP.
10. How is the monomer of PAN prepared?

 

PART-B

 

Answer any EIGHT questions.                                                                        (8×5=40 marks)

 

11. A polymer sample consists of 5 moles of molecular weight 30,000, five moles of molecular weight 40,000 and 10 moles of molecular weight 50,000. Calculate  and .
12. Discuss the polymerization of acetonitrile in the presence of Li NH₂.
13. Explain gas phase polymerization with an example.
14. Stilbene and maleic anhydride fail to undergo self polymerization but these two react to give exclusively alternating co-polymer.
15. What are epoxy polymers? How are these prepared?
16. Give an example of photostabilizer and mention its requirement.
17. Write a note on Fibre Reinforcing Plastics.
18. Define cohesive energy and account for the high cohesive energy of polyamide.
19. What should be the criteria of conducting polymers? Give two examples of conducting polymers.

 

20. Give an example for each:

• Man made fibre
• Natural fibre
• Natural rubber
• Synthetic rubber
• Thermosetting plastic.

 

PART-C

 

Answer any FOUR questions.                                                                         (4×10=40 marks)

 

21. Discuss the secondary bond forces in polymers.
22. What are stereoregular polymers? Give examples. How are these obtained?  Discuss the mechanism for the preparation stereoregular polymers.
23. Discuss emulsion polymerization.
24. Give an account of thermal degradation of polymers.
25. Write notes on

• Injection moulding
• Callendering

26. (i) Distinguish homopolymes and co-polymers.

(ii) Give the preparation and the uses of polystyrene and phenolformaldehyde resin.

 

 

 

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