Base-catalyzed cyclization of ortho-aromatic amide-alkyl esters: a novel approach to chemical imidization

In our study of poly(amic alkyl esters) we have made a couple of peculiar observations, which appeared to be related to partial imidization of these polyimide precursors by the presenceof amines. Based on these observations we decided to investigate this phenomenon in greater detail and explore the possibility of utilizing this behavior to chemically imidize poly(amic alkyl esters). In summary, the base-catalyzed imidization of ortho-aromatic amide-alkyl esters provides a convenient pathway to the preparation of low molecular weight imide compounds and offers an attractive alternative for the complete imidization of poly(amic alkyl esters) at significantly lower temperatures. Of course, this is particularly desirable for curing these materials in the presence of materials incompatible with the otherwise high thermal excursion necessary to achieve complete imidization. In addition, photogeneration of bases to yield photosensitive polyimide systems appears feasable.