WORK DONE ON POLYMERS.


        Different types of polymers were synthesized and the polymeric structure with electrical, thermal and mechanical properties were studied in detail depending on the application of these polymers.

  1. SPECIALITY POLYMERS-CONDUCTING POLYMERS

            Conducting poly thiophenes and Poly pyrroles were synthesised with a view to understand the effect of substituents and the dopants on the properties of the polymer.

            Morphological and mechanical property studies were also undertaken with 3?substituted thiophene polymers. The improvement in electrical and mechanical properties produced due to thermal orientation was studied in detail. Fracture behaviour of the 3- substituted thiophene polymers at different temperatures was also studied.

            Langmuir-Blodgett films of the substituted polythiophenes were prepared and the thin film characteristics were studied.

            Poly alkyl thiophene copolymer and blends were prepared and the properties were studied.

            Conducting Polymer composite was developed and the studies with this composite show that the material is useful as EMI shielding.

            The results obtained on the substituted polythiophenes show their potentiality in electronic devices like schotkey diodes and light emitting diodes. Many polymer based donor/acceptor conjugated polymers/ copolymers were synthesised for photovoltoic applications.

            In addition to electrically conducting systems, proton conducting polymeric systems were also studied in order to correlate for fuel cell applications.

  2. GRAFTS

    • Natural polymers

              Casein, a widely used biopolymer, was modified to make it more useful as a product for applications in leather, textiles and paper industries. Modifications like plasticisation, partial hydrolysis, crosslinking and grafting with single and mixed monomers were tried. The structure-property relationships were assessed after every modification.
              Factors that influence the mechanical properties and hence create problems in application, like temperature, strain rate, absorbed moisture etc. were taken into consideration and were critically analysed and correlated with the structure. Fracture behaviour and the failure mechanisms were also studied.
              On one hand this piece of work was helpful to get casein films with improved properties, suitable for applications and on the other, it helped to understand the basic material science aspects of casein at different modification levels.
              Similarly grafting of gelatin was done with acrylic monomers in order to improve the properties.

    • Polyester fibers

              Polyester fiber has two drawbacks due to its rigid structure, Viz. problems in dye uptake and moisture absorption. This can be solved by incorporating polar sites in the molecule. Monomers containing polar groups like acrylonitrile, methacrylic acid, acrylic acid, acrylamide were grafted. The dye uptake and moisture absorption improved considerably without affecting the overall properties of polyester fibers.

  3. BLENDS

            Blending suitably with other polymers depending on the required property can modify the properties of the polymers. Polymers like Poly acrylonitrile), Polystyrene, Poly methyl methacrylate were blended with polymers of acrylic and methacrylic esters and the compatibility and other properties of the blends were analysed using ultrasound and other sophisticated techniques.

            Polyamide hot melt resin was blended with other polymers like EVA, Polystyrene and the properties of the blends were studied for their suitability as an Hot melt adhesive.


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