This investigation of polybenzimidazole synthesis involved the two-stage low temperature solution polymerization of dialdehydes, One-step polycondensation of dialdehydes, two-stage melt polycondensation of diesters, and one-step solution polycondensation of diesters with 3,3'-diaminobenzidine. Dialdehyde or diester monomers were prepared which contained aromatic units which were hooked together with sulfonate linkages. Polymerization of...