Investigation on low-velocity impact and interfacial bonding properties of weft-knitted UHMWPE reinforced composites

In this study, low-velocity impact and interfacial bonding properties of weft-knitted ultra-high-molecular-weight-polyethylene (UHMWPE) filaments reinforced epoxy resin and vinyl ester resin composites were investigated. UHMWPE filament yarns of 600 D were applied to fabricate three weft-knitted structures of plain stitch, interlock air space stitch and swiss double pique. Vacuum-assisted resin infusion (VARI) technology was utilized to combine resin and fabric to form inter-ply hybrid rigid composites. The basic mechanics, impact resistance and puncture performance of the hybrid composites were evaluated and their interfacial bonding was analyzed. It was revealed that composites with interlock air space stitch reinforcement exhibited the highest mechanical properties and puncture resistance. Under the same weft-knitted reinforcement, the tensile and flexural properties of the epoxy matrix composites were better than vinyl ester matrix composites. However, their low-velocity impact resistance was a bit inferior. The interfacial bonding ability between vinyl ester resin and weft knitting structure reinforcement was stronger because of the similar material structure between resin and reinforcement. This process is important for determining the optimum bonding method to achieve extensive application and improve the shelf life of UHMWPE composites.