Abstract: Novel polyimide prepolymers are produced by reacting an unsaturated dicarboxylic acid imido acylchloride with a difunctional amine to produce the corresponding acid amide. Condensation of said reactants is preferably effected in solution in a low boiling solvent. The resulting prepolymer is hardened and completely polymerized by heating, preferably between about 80.degree. C. and about 400.degree. C., to yield a cross-linked, substantially infusible and insoluble polyimide resin and articles made therefrom.

Abstract: Novel imide resins are prepared by reacting a bisimide of an unsaturated dicarboxylic acid with a dihydrazide of a dicarboxylic acid, preferably in an organic solvent or diluent at elevated temperature for a period of time insufficient to yield an insoluble, infusible, fully cured imide resin. Solutions of the resulting prepolymerization product are stable at room temperature and their viscosity remains substantially unchanged for a prolonged period of time. Fully cured imide resins and articles thereof of a high heat resistance are obtained by heating said prepolymerized imide resin or materials such as fibers, metal wire webs, and others impregnated therewith, if desired, in the presence of curing catalysts, inhibitors, fillers, and other materials, to curing temperature up to 350.degree. C.

Abstract: Novel thermosetting imide resins are obtained by reacting an N,N'-bisimide of an unsaturated dicarboxylic acid with the hydrazide of an amino acid, preferably in the molar proportion between about 1.1 and about 10.0. The resulting prepolymerization products can also be prepared in organic solvents or diluents. By heating at atmospheric pressure or under pressure to a temperature between about 100.degree. C. and about 350.degree. C. and preferably between about 160.degree. C. and 260.degree. C., if desired, in the presence of curing catalysts or inhibitors, the prepolymerization products are cured and hardened to substantially insoluble, infusible, highly cross-linked imide resins of superior stability at high temperatures. Solutions of the prepolymerization products have the advantage that they are stable at room temperature for an almost unlimited period of time without any substantial increase in their viscosity.

Abstract: Filament-wound reinforced plastic articles and parts thereof are obtained by wetting and impregnating filaments, rovings, webs, and the like fibrous materials consisting of glass, carbon, graphite, boron, steel, asbestos, temperature resistant organic fibers, and the like with a liquid or liquefied polymerizable organic compound of a high melting point which can be polymerized by addition polymerization, and converting the wetted fibrous material into the desired wound plastic article or part thereof by winding around a mandrel and then subjecting the wound article to addition polymerization. Wetting and winding with the polymerizable organic compound are effected under conditions under which substantially no polymerization takes place. Especially suitable polymerizable organic compounds are bisimides such as the bismaleimides of a melting point which is at least 20.degree. C. below the temperature required for polymerization.