Interlaminar properties of carbon fiber composite laminates with resin transfer molding/prepreg co-curing process

Abstract

Co-cured resin transfer molding (co-RTM) process, which combined resin transfer molding (RTM) process with prepreg process, was adopted to fabricate carbon fiber/epoxy resin laminates. The compatibility between prepreg resin and injection resin was investigated by nano-indention test and glass transition temperature with different resin mixture ratios. Processing quality of co-RTM laminates was evaluated by optical micrographs and thickness dimension. Mode I ( GIC) and mode II ( GIIC) interlaminar fracture toughness tests were measured to characterize the mechanical properties of co-cured interface. Moreover, prepreg resin impregnation into fiber fabric was studied by fluorescent micrographs and its influences on processing quality and interlaminar property were analyzed. The results show that good resin compatibility can be obtained between two resin systems. There are no obvious defects except for some resin rich region at co-cured interface for co-RTM laminates. The GIC and GIIC test values of co-RTM laminates locate between those of prepreg laminates and RTM laminates, which exhibit no weak effect occurs at co-cured interface. In addition, increasing holding temperature and prolonging holding time promote prepreg resin impregnation effect, improving the fiber compaction and interlaminar performances at co-cured interface. Therefore, co-RTM process is a hopeful technique for manufacturing composite structure with effective cost saving.