| abstract |
This invention provides an improved type of high molecular weight polybenzimidazole, which involves the use of a phosphorus-containing 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 0.7 dl/g, and a weight average molecular weight of at least about 100,000. |