M.Sc. (Semester IV) (CBCS) Examination Nov/Dec-2018
Polymer Chemistry
STEP-GROWTH OF POLYMERS
Time: 2½ Hours
Max. Marks: 70
Instructions: Attempt in all five questions. Section I is compulsory Attempt any two questions from section II. Attempt any two questions from section III. All questions carry equal mark. Figures to right indicate full marks. Use of log table non programmable calculator is allowed.
Section I
Q.1
Answer the following:
14
By chemical equation only show steps involved in the preparation of Diphenyl carbonate.
Name and draw chemical structure of the material used for curing Novolac-PF resin.
Draw the structure of repeat unit of Glyptal resin.
Polycarbonate derived from Bisphenol-A is finds application in "Baby milk bottle" Give reasons.
What is the meaning of TDI 80:20 and where it is used?
What is the concentration of formaldehyde in commercial formalin? How is it prepared?
Give one example of Lyotropic liquid crystal and draw its structure.
Section II
Q.2
Discuss the Marvel's mechanism for cross linking process in UF resin. What are important properties and applications of UF resin?
07
Describe the synthesis of poly (para-phenylene) polymer. Discuss its properties and applications.
07
Q.3
Explain the transestrification method for manufacture of PBT and state two important properties of PBT.
07
Discuss a synthetic method for epoxy resin and state its important properties and applications.
07
Q.4
Explain difference in chemical intermediates and prepolymer structures when phenol reacts with formaldehyde in presence of acid and base catalysts.
07
Discuss the preparation of Nylon-6 and Nomex; comment on
07
Monomers used
Polymerization process used and
Tensile properties of fibers, both for Nylon-6 and Nomex.
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SLR-VF-157
Section III
Q.5
Explain the meaning of term Hy-951 and draw its chemical structure. Where Hy-951 is used and list out its limitations
05
Explain one method each for preparation of
05
HMDA and
Azelic acid
With the help of suitable examples, explain the effect of methylene linkages on the properties of polyesters.
04
Q.6
Organic compound with molecular formula C6H10 on oxidation in presence of alkaline KMnO4 gives aromatic diacid having molecular formula C8H6O4. The reaction of this diacid with excess of methanol gives diester with molecular formula C10H10O4. The reaction of the diester with diol with molecular formula C3H8O2 in presence of acid catalyst gives commercial polymers called 3GT. Draw the structure of repeating unit for this polymer. Justify your conclusion.
05
List out important properties of MF resin. State important properties of MF resin to be used for manufacture of high quality dinnerware.
05
Discuss the role of PTC in synthesis of polycarbonate by Interfacial method. List out advantages of this method.
04
Q.7
Write a short note on any Three of the following.
14
Addition type polyimides
Polyurethane foams preparations, properties and applications
Unsaturated network polyester
Curing agents used in epoxy resins
Nomenclature method for nylons