Synthesis of methylated phenylene sulfide polymers via bulk oxidative polymerization and their heat curing triggered by dynamic disulfide exchange

摘要

Poly(2,5-dimethyl-1,4-phenylenesulfide) (PMPS) was prepared without halogenated compounds via oxygen oxidative polymerization of bis(2,5-dimethylphenyl) disulfide (2,5-DPS) with a VO(acac)(2)-strong acid catalyst under bulk conditions. The polymer showed crystalline features with a high melting temperature (T-m = 268 degrees C). After the subsequent heat curing of PMPS through the exchange reaction of a reactive disulfide bond, the polymer had a higher melting temperature (T-m = 286 degrees C), which was even higher than that of conventional poly(p-phenylene sulfide) (PPS) (T-m = 283 degrees C). Furthermore, the copolymerization of 2,5-DPS with diphenyl disulfide (DPS) led to products with higher crystallinities and melting temperatures owing to the increase in their molecular weights, which was derived from these products having higher solubilities in the monomer melt than PMPS.