Process for making polyimides.

摘要

A process for making polyimides involves the steps of reacting an aromatic dianhydride with a lower aliphatic alcohol to form a diester diacid, combining the diester diacid with an organic diamine to form an ester-ammonium carboxylate salt, then heating the ester-ammonium carboxylate salt under imidization conditions to form the desired polyimide. The invention also relates to novel diester diacids used as intermediates in the foregoing process.