Two stage high molecular weight polybenzimidazole production with phosphorus containing catalyst

摘要

This invention provides a two stage melt polymerization process for the production of an improved type of high molecular weight polybenzimidazole, which involves the use of an arylphosphine or arylphosphite polymerization catalyst. The process provides poly-2,2'-(m-phenylene)-5-5'-bibenzimidazole of improved color and Plugging Value, and is further characterized by an inherent viscosity of at least about 0.9 dl/g, and a weight average molecular weight of at least about 140,000.