| 摘要 |
The resins described herein are polyimide-epoxy thermoset resins prepared by reacting a polyepoxide with a solution of an admixture of a polyimide dianhydride with another polyimide component, either a polyimide dianhydride or a polyimide diamine, at least one of which polyimide components is insoluble in the particular solvent in the absence of the other polyimide component or components. "Polyimide dianhydride" is an anhydride-terminated polyimide and "polyimide diamine" is an amine-terminated polyimide as represented by the respective formulas: <IMAGE> and <IMAGE> wherein Ar', Ar and n are as defined hereinafter. For use in the present compositions, the polyimide dianhydride has an anhydride activity of at least 0.17 as defined herein, and the ratio of epoxy equivalent to anhydride plus amine equivalents is at least 1/1. By employing a two step reaction scheme, the process offers a more tractable polyimide-epoxy intermediate resin that can be processed into void-free products with superior mechanical properties than polyimide-epoxy thermosets shown in the prior art.
|
