IM7 LARC(TM) MPEI-1 POLYIMIDE COMPOSITES

LARC(TM) MPEI-1 (Langley Research Center(TM) modified phenylethynyl im ide-1) phenylethynyl containing aromatic polyimide, is based on the re action of biphenyl dianhydride (BPDA), 3, 4'-oxydianiline (3, 4'-ODA), 1,3-bis(3-aminophenoxy)benzene (APB), 2,4,6-triaminopyrimidine (TAP) and 4-phenylethynyl phthalic anhydride (PEPA), presumably resulting in a mixture of linear, branched and star shaped phenylethynyl containin g imides which was evaluated as a matrix for high-performance composit es. The poly(amid acid) solution of MPEI-1 in N-methypyrrolidinone was synthesized at 35% and 42% solids. Unidirectional prepreg was fabrica ted from these solutions and Hercules IM7 carbon fibre utilizing NASA- Langley's multipurpose prepreg machine. The temperature-dependent vola tile depletion rates, thermal crystallization behaviour and resin rheo logy were characterized. Based on this information, a composite mouldi ng cycle was developed which yielded well consolidated, void-free lami nates. Composite mechanical properties such as short beam shear streng th, longitudinal and transverse flexural strength and flexural modulus , longitudinal tensile strength and notched and unnotched compression strengths were measured at room temperature (RT) and elevated temperat ures. These mechanical properties are compared with those of IM7/LARC( TM) PETI-5 composites.