M.Sc. (Semester IV) (CBCS) Examination Mar/Apr-2018
Polymer Chemistry
PROCESSING TECHNOLOGY AND POLYMER PROPERTIES
Time: 2½ Hours
Max. Marks: 70
Instructions: Attempt five questions. All question carry equal marks. Section I is compulsory. Attempt any two questions from section II and two from section III. Answer to all questions (section II, III) should be written in the one answer book. Figures to the right indicate full marks. Use of log table and calculators is allowed.
Section-I
Q.1
Answer the following:
14
Define HDT.
When fluid is known as non-Newtonian?
How bulk density is different than normal density?
Which of the given polymer articles will melt after heating?
Given polymers- polyethylene, Bakelite, epoxy, polypropylene, unsaturated polyester, polystyrene.
How will you define acid value?
Which of the given polymers will show sooty flame when burned?
Given polymers polystyrene, polyethyleneterephthalate polyethylene, polypropylene
Define rheology.
Why polymers show viscoleastic behavior?
What is principle of transfer moulding?
Define hardness of polymers.
Which shows highest elongation among rubber, fiber and brittle plastics?
Why it is necessary to process the polymer?
Define Young's modulus.
Mention the names of thermal techniques used to estimate melting range of polymers.
Section-II
Q.2
Discuss measurement of volume resistivity and breakdown voltage. What is their importance?
07
Explain any two optical properties of polymers in detail.
07
Q.3
Explain stress-strain curve for elastomeric, tough and brittle polymers. Also explain various terms involved in it.
07
Describe working Maxwell and Voight models of viscoelasticity.
07
Q.4
Define impact strength. Discuss determination and significance of it in applications of plastics.
07
Why compression modulus shows higher values than tensile modulus? Explain the process of determination of compression modulus.
07
Page 2 of 2
SLR-UF-207
Section-III
Q.5
Write principle of injection moulding. Explain again injection moulding process with neat labeled diagram.
05
Discuss blow moulding of plastics in detail.
05
Explain the ways to minimize shrinkage and distortion in injection moulding.
04
Q.6
Explain models representing viscoelastic behavior of polymers.
05
Which equipment is suitable for studying dynamic mechanical behavior of plastics? Discuss about storage and loss moduli.
05
What are general features of twin screw extruder?
04
Q.7
Write a note on any Three of the following.
14
Stress relaxation
Reaction injection moulding
Compression moulding
Comment on importance of moisture content in polymers