Effects of resin consolidation on the durability of IM7/PETI-5 composites

An experimental study was undertaken to investigate the mechanical response of the graphite fiber reinforced thermoplastic polyimide composite IM7/LaR C(TM)-PETI-5 for use in long term durability tests. Composite panels were p repared using unidirectional prepreg and regions of different resin consoli dation were identified using a nondestructive ultrasonic technique. Specime ns representing four different degrees of resin consolidation were tested a t room temperature in tension, compression, and flexure in the as-received state, as well as isothermally exposed for 1500 h at 177 degreesC, and isot hermally exposed to a "hot/wet" environment (80 degreesC, 90% + relative hu midity). Results showed that specimens tested in tension and compression ha d a higher dependence on resin consolidation than those tested in flexure, However, specimens tested in flexure showed a greater property degradation from environmental exposure due to a lack of resin consolidation.