Bead polymerization process for preparing polybenzimidazole
AssigneeE. I. Du Pont de Nemours and Company
InventorGeorge N. Milford, Jr.
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Abstract
Polybenzimidazoles are prepared in the form of small particles by reaction of bis(o-diamine) substituted compounds with dicarboxylic acids or of o-diamino-substituted carboxylic acids in the presence of an inert, nonsolvent, liquid medium and polyphosphoric acid.
Claims5
Process for the preparation of polybenzimidazole in the form of small particles from at least one aromatic compound selected from the group consisting of o-diamino-substituted carboxylic acid compounds by contacting at least one o-diamino-substituted carboxylic acid compound with an excess of polyphosphoric acid dehydrating agent in an inert, nonsolvent, liquid medium, heating to 120.degree.-230.degree. C. for 1-4 hours with stirring, cooling to room temperature with continued stirring and filtering to remove polybenzimidazole which is washed to remove impurities.
Dependencies are inferred from the claim text.