Synthesis and characterization of epoxy film cured with reactive polyimide

Reactive polyimide containing hydroxyl functionalities was prepared from the reaction of 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride and 3,3'-diamino-4,4'-dihydroxybiphenyl, Commercial epoxy resin was cured in the presence of different ratios of the reactive polyimide, giving a series of polyimide modified epoxy films. The transparent films had excellent solvent resistance. The tensile measurements of the films showed that, with the increase of the polyimide content, tensile modulus of the film increased but there was almost no change in the elongation at break. Viscoelastic measurements showed that glass transition temperature shifted with the increase of the polyimide content; 127 degrees C for 13.5%, 220 degrees C for 29.4%, 260 degrees C for 45.4% and 290 degrees C for 62.5%. Thermogravimetric analysis showed the increase of the thermal stability with the increase of the polyimide content. (C) 1999 Elsevier Science Ltd. All rights reserved.