ADHESION BEHAVIOR OF POLYAMIC ACID CURED EPOXY

The adhesion behaviour or lack thereof, of polyimides is well known. T he inherent brittleness of epoxy resins has also led to a search for a dditives to improve the physical properties of epoxy. In order to impr ove both of these properties, we utilized a unique strategy to cue a d iepoxy (diglycidyl ether of bisphenol A) with a polyamic acid derived from oxydianiline and pyromellitic dianhydride. The polyamic acid synt hesis was conducted in a low boiling point solvent consisting of tetra hydrofuran and methanol (80/20) and nor traditional high boiling point aprotic solvents such as dimethylacetamide. This resulted in a materi al that had adhesion superior to both the pure epoxy and the pure poly imide. The state of cure was also seen to have an effect of the adhesi on strengths. (C) 1997 Elsevier Science Ltd.