A series of copolymers from 3,3',4,4'-benzophenonetetracarboxylic dianhydri
de and 3,3',4,4'-biphenyltetracarboxylic dianhydride and two diamines, 4,4'
-diaminodiphenylether and 3,5-diaminobenzoic acid, were synthesized. The in
fluence of various ratios of diamines on the properties of polymers were in
vestigated. A preliminary study on the potential of using the carboxylic ac
id group for substitution was carried out.