Synthesis and characterization of thienyl- and terthienyl-group-bearing methacrylic polymers as precursors for grafting reactions of thiophene side-chains

Acrylic and methacrylic monomers bearing pyrrolyl, thienyl and terthienyl groups, were synthesized and copolymerized with various amounts of butyl acrylate and butyl methacrylate. In the resulting copolymers the heterocycle side-groups behaved as initiators in the oxidative polymerization of thiophene, allowing the polythiophene chains to grow from the side-groups and leading therefore to graft copolymers. These last were collected mostly as insoluble fractions after extraction with chloroform. Processible polymers with polythiophene side-chains were obtained when in the precursor polymer the heterocycle side-group content was very low. The presence in the graft copolymers of a significant number of stiff polythiophene side-chains was responsible for the rise in Tg values in comparison with the precursor polymers. The average number of grafted thiophene units, evaluated in the range 2-7.5, did not relate directly to measured conductivity values that were in the range 5.9 x 10(-5)-6.2 x 10(-2) Scm(-1).