Synthesis and characterization of polymers bearing pyrazole groups, 1. Methacrylic derivatives

The synthesis of new methacrylic monomers H2CC(CH3)COOCH2G where G is a pyridine, a pyrazole or a bipyrazole group has been achieved. Their homopolymerization was studied and gave fairly low molecular mass polymers. Their copolymerization with styrene gave copolymers tending to be alternating when the bulkiness of group G increased. Moreover, in the presence of Lewis acids the monomers were complexed. With ZnCl2, they were complexed through nitrogen atoms and were shown to be inactive in copolymerization. With SnCl4, they were complexed through the carbonyl group and gave alternating copolymers. The homopolymers exhibited low glass transition temperatures (50–76°C) and moderate thermal stability (decomposition begins at ca. 200–280°C and is complete at 550°C). In the copolymers with styrene the thermal properties showed to be improved.