Polyimide

Abstract

This invention relates to a novel polyimide or polyimide copolymer having excellent heat resistance and greatly improved processability, and has a novel aromatic diamino compound used for the polyimide, a preparation process thereof, a polyimide-based resin composition comprising the polyimide or polyimide copolymer and a fibrous reinforcement, a process for preparing the resin composition, an injection molded article of the resin composition. The polyimide comprise a requisite structural unit having one or more recurring structural units of the formula: ##STR1## wherein L is an oxygen atom, carbonyl, isopropylidene or hexafluoroisopropylidene, and X is ##STR2## and Ar is a tetravalent radical having 6 to 27 carbon atoms and being selected from the group consisting of a monoaromatic radical, condensed polyaromatic radical and noncondensed polyaromatic radical having aromatic radicals connected to each other with a direct bond or a bridge member. The polyimide or polyimide copolymer is outstanding in melt-flow stability, and has greatly improved processability and excellent heat resistance. Consequently, the polyimide or polyimide copolymer can be applied to structural materials, and electic.cndot.electronic appliances.