Rapid Processing of Nanomaterial-reinforced Carbon Fiber/Nylon 6 Hybrid Composites Using Thermoplastic Resin Transfer Molding (T-RTM)

Abstract

Despite their advantages of high impact resistance and recyclability as compared to thermoset composites, the main hurdle for efficient processing of fiber-reinforced thermoplastic composites has been the difficulties associated with impregnating high-viscosity resin in the molten state into continuous fiber textile. Reaction injection molding has been a widely practiced processing method for fiber-reinforced thermoset composites; however, a similar concept for thermoplastics, known as thermoplastic resin transfer molding ("T-RTM") has been developed only recently. We have demonstrated T-RTM for caprolactam (CL), a precursor to Nylon 6 (A-PA6), in which the thermoplastic resin in the low-viscosity monomer state is injected into the mold charged with a fiber preform. Upon injection, the monomer reacts immediately with the pre-mixed initiator and catalyst, leading to polymerization and composite part completion. As the first step, we optimized the T-RTM process by identifying the best combination of initiator and catalyst contents, and polymerization time, such that monomer conversion rate is maximized while allowing a reasonable processing window. Then, we investigated the effects of adding nanomaterials (NMs, e.g., nanoclay, carbon nanotube, (reduced) graphene oxide, exfoliated graphite nanoplatelet, etc.) on the mechanical properties of the T-RTM-ed continuous-carbon-fiber-reinforced Nylon 6 composites. The relationships between various material/process parameters and the mechanical properties of the composites are discussed. © 2017 The Composites and Advanced Materials Expo (CAMX). All rights reserved.