Synergistic toughening of carbon fiber/vinyl ester resin composites with core–shell rubber particles and polyphenylene sulfide veils

Abstract In this work, the interlaminar fracture toughness of carbon fiber/vinyl ester resin (VER) composites was improved through the synergistic effects of core–shell rubber (CSR) particles and polyphenylene sulfide (PPS) veils. First, a systematic investigation was conducted to assess the impact of the CSR particles on the viscosity, tensile properties, fracture toughness, and thermal properties of the modified VERs. Compared with the pristine VER, the modified VER containing 10 wt% CSR particles exhibits a 124% improvement in the critical stress intensity factor (K_IC) and a 512% improvement in the critical strain energy release rate (G_IC). The predicted tensile properties and fracture toughness calculated by the empirical formulas and theoretical models show a good concordance with the measured values. Compared with those of the unmodified composite, the Mode I and Mode II interlaminar fracture toughness of the composite modified by the CSR particles and PPS veils increase by 110% and 132%, respectively. Scanning electron microscopy observations indicate that the multiscale toughening mechanisms include matrix plastic deformation, plastic void growth, fiber pull‐out, fiber breakage, fiber bridging and so forth. Highlights The toughening behavior of CSR particle‐modified VERs was investigated. Empirical formulas and theoretical models were used. The synergistic toughening effect was exerted by CSR particles and PPS veils.