Lower‐curing‐Temperature PMR polyimides

Abstract Studies were performed to achieve lower‐curing temperature PMR (polymerization of monomer reactants) polyimides. Partial substitution of a p‐aminostyrene end‐cap for the monomethyl ester of 5‐norbornene‐2,3‐dicarboxylic acid lowered the final cure temperature of typical PMR resins from 600 to 500°F. The weight‐loss characteristics of neat resins and graphite fiber composites prepared by using the mixed end‐cap approach were determined at 600°F. The room temperature and short‐term elevated temperature mechanical properties of the composites at 550°F and 600°F were determined. The mechanical‐property‐retention characteristics of the composites at 550°F and 600°F are also discussed.