M.Sc. (Semester III) (CBCS) Examination Mar/Apr-2018
Polymer Chemistry
MORPHOLOGY AND PHYSICAL CHEMISTRY OF POLYMERS
Time: 2½ Hours
Max. Marks: 70
Instructions: Attempt all five questions. Section-I is compulsory. Attempt any two questions from Section-II and any two questions from Section-III. Answer to all 05 questions (from section II, III) should be written in the one and the same answer book. All question carry equal marks. Figures to the right indicate full marks. Use of log table and calculators is allowed.
Section I
Q.1
Answer the following.
14
What is below theta temperature?
How can ultra centrifugation be used to distinguish between a styrene- isoprene copolymer and a mixture of polystyrene and polyisoprene?
What are photostabilizers? Give one example.
What is regular and irregular single crystal?
What is entropy of mixing in polymer solution?
Define the term Biodegradation.
Show the schematic illustration of the spherulite structure.
Section II
Q.2
What is ultracentrifugation? How sedimentation process may be exploited to determine polymer molecular weight?
07
Explain Kringbaun-Flory theory of polymer solution.
07
Q.3
Explain Basic principle of DSC and TMA. How these techniques used to identify crystalinity of polymer?
07
What is antioxidant? How can you stabilize polymer materials from oxidation process?
07
Q.4
Explain Florry-Huggins theory with mean field concepts. What are it's limitation?
07
What is GPC? Explain GPC techniques for obtaining number average and weight average molecular weight for the polymer sample.
07
Section III
Q.5
What is single crystal?
05
The osmotic pressure of solution of poly(vinyl chloride) in cyclohexane at 298 K are presented below in Table 1. The density of the polymer solution is 0.980 g cm-3. Determine the molecular weight of the polymer.
05
Concentration
1.00
2.00
4.00
7.00
9.00
Height
0.28
0.71
2.01
5.10
8.00
Explain Thermal degradation.
04
Q.6
Describe various involved in polymer dissolution.
05
Define the terms
number average molecular weight
ii) weight average molecular weight
iii) viscosity average molecular weight
iv) weight average weight molecular weight and
polydispersity.
05
Distinguish between crystalline and amorphous morphology of polymer.
04
Q.7
Write a note on any three of the following.
14
End group analysis
Heat dissolution
Photodegradation
Crystalinity
Viscosity dilution