Synthesis and Characterization of Ion-exchange Copolyimide

A new diamine, disodium 4, 4'-di(4-aminophenoxy)-3, 3'-disulfonate-1, 1'-diphenyl-ketone, was prepared from the nucleophilic substitution of disodium 4, 4'-difluoro-3, 3'-di-sulfonate-1, 1'-diphenylketone and p-aminophenol. Polymerization of this diamine and 4, 4'-diamino-1, 1'-diphenyl ether with 3, 3', 4, 4'-tetracarboxyl dianhydride-1, 1'-diphenyl ketone gave ion-exchange copolyimide. The new diamine and its polyimide were characterized with 1H-NMR and FT-IR.