Characterization of the interfacial shear strength of glass-fiber reinforced polymers made from novel RTM processes

Abstract

In this study, three different glass fiber reinforced polymers have been investigated with respect to the interfacial shear strength. Conventional resin transfer molding (RTM) and the compression RTM (CRTM) process for the production of reinforced samples with an epoxy matrix were chosen. The third process was a thermoplastic RTM (TRTM) process for producing composites with a thermoplastic polyamide 6 matrix. Fiber type and coupling agent were not varied. The interfacial shear strengths reached by the different processing routes were determined by push-out tests. It is shown that the RTM interface shear strength is very high and comparable to that generated by the CRTM process, despite increased fiber fracture for the RTM samples. The TRTM process yielded significantly lower interfacial shear strength values. Plastographic analysis of the material systems showed the formation of an interfacial layer between the fibers and the thermoset matrix. For the thermoplastic matrix a significant lower formation of crystalline spherulites at the interface and no interfacial layer could be observed.