LOYOLA COLLEGE (AUTONOMOUS), CHENNAI – 600 034
B.Sc. DEGREE EXAMINATION – CHEMISTRY
FIFTH SEMESTER – APRIL 2011
CH 5402/5400 – POLYMER CHEMISTRY
Date : 12-04-2011 Dept. No. Max. : 100 Marks
Time : 9:00 – 12:00
Part – A (Answer all questions) (10 x 2 = 20)
- How are polymers classified on the basis of their origin?
- What are reinforced plastics? Give an example.
- Distinguish between organic and inorganic polymers.
- How is polystyrene prepared?
- What is coordination polymerization? Give an example.
- What are the causes of chain end degradation?
- What is ion-pair precipitation?
- Account for the thermal stability of PTFE.
- What are addition and condensation polymerizations?
- Mention the significance of organosols.
Part – B (Answer any EIGHT only) (8 x 5 =40)
- Explain Natta’s bimetallic mechanism of polymerization.
- Discuss the different types of polycondensation.
- Explain copolymerization and homopolymerisation with examples.
- What are zipping and unzipping? Give examples.
- Explain interfacial condensation polymerization with an example.
- Give the preparations and applications of LDPE and HDPE?
- How are linear and cross-linked phenol-formaldehyde resins obtained?
- Explain inter and intra molecular chain transfer.
- How will you remove the defects in polypropylene polymer?
- Describe polyaddition polymerization with an example.
- Discuss the mechanism of anionic polymerization.
- How are isotactic and syndiotactic polymers obtained?
Part – C (Answer any FOUR only) (4 x 10 =40)
- a) Discuss the primary and secondary bond forces present in polymer (6)
- b) Chain polymerization is also called vinyl polymerization – explain. (4)
- Why is the molecular weight of a polymer expressed as an average? Describe the weight average molecular weight determination of a polymer.
- a) Explain the various possible modes of addition in the propagation step of free radical polymerization. (6)
- b) Why are inhibitors called short stops? Mention their uses. (4)
- a) Explain i) Blow moulding ii) Injection moulding (6)
- b) Write a note on compounding. (4)
- a) Discuss the role of metering and feed zones in extrusion moulding. (5)
- b) Writ a note on elastomeric materials and fibre forming polymers. (5)
- Discuss the mechanisms of conduction exhibited by polyphenylene and polyacetylene polymers.
Latest Govt Job & Exam Updates: