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IV Semester M.Sc. Degree Examination, June 2016 (NS) Chemistry C – 403 : CHEMISTRY OF MATERIALS (Common to IC/AC) Time : 3 Hours

Max. Marks : 80

Instruction : Answer question No. 1 and any five of the remaining. 1. Answer any ten of the following.

(10×2=20)

a) Why whiskers are not preferred over fibers as reinforcing medium in composite manufacturing ? b) Why the reactants have to be in highly dispersed phase and possess high chemical energy in combustion synthesis ? c) Distinguish between thermotropic and lyotropic liquid crystals with examples. d) Enumerate the process variables influencing amorphous metallic ribbons manufactured by melt spinning technique. e) What are metathetic reactions ? Give an example. f) Discuss the role of matrix phase in fiber reinforced composite. g) What are the structural defects responsible for high conductivity in α -alumina ? h) What are LB films ? How are they formed ? i) Write the principle of formation of nano materials by sputtering process. j) What are high Tc oxides ? Write any two examples with their Tc values. k) How metal nano particles are synthesized from their aqueous salt solutions using an organic reducing agent ? Write an example. l) Distinguish between classical model and Daumas-Herold model of staging of graphite intercalation compounds.

P.T.O.

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2. a) Describe any two functionalization strategies of carbon nano tubes with suitable illustrations. b) Explain the preparation of nano sized materials by chemical vapour deposition method with a neat sketch. c) Explain the synthesis of nano rod through surfactant mediated template approach. (4+4+4) 3. a) Explain the conductivity mechanism in PA and PPP molecules. Write their differences. b) Describe the preparation of fullerenses by graphite arc method. c) Discuss the applications of nano metal oxide particles in environmental mitigation. (4+4+4) 4. a) Explain the condensation mechanism of H-O bonds in sol-gel synthesis of solids. b) Give the preparation of solids by electrochemical route ? What are its limitations ? c) Give an account of the preparation of LaBa2Cu3O7.

(4+4+4)

5. a) Explain the structural changes in the host lattice which are highly flexible in its nature when intercalation reaction proceeds with a suitable illustration. b) Discuss the structural features of zeolites suitable for membranes in ion purification systems. c) What are discotic crystals ? Explain their structure with suitable examples. (4+4+4) 6. a) Explain the structure and property differences between dispersion strengthened and particle reinforced composites. b) Describe the influence of fibre length on the reinforcing efficiency of fibre reinforced composite.

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c) A continuous aligned fibre reinforced composite has been synthesized containing 40 vol % aramide fibres having elasticity modulus 148.2 Gpa and 60 vol% of polyamide matrix having modulus of 1.98 GPa. Find the elasticity of modulus of this compound in transverse direction. (4+4+4) 7. a) Explain the preparation of amorphous thin films by sputtering process with a neat sketch. b) Describe the optical properties of liquid crystals with suitable examples. c) Discuss the mechanical properties of amorphous materials.

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(4+4+4)