▎ 摘　　要

The role of nanoparticles in the fracture toughness of glass fiber-reinforced polyester composites (GFRPs) was investigated. An unsaturated polyester resin (UPR) and a vinyl ester resin (VER) were toughened by two distinct methods: (1) incorporating a very low loading (0.04 wt%) of alkyl or vinyl modified graphene oxide (mGO); or (2) adding core-shell rubber (CSR, 1 and 5 wt%). For unreinforced resins, results from compact tension tests revealed that adding 0.04 wt% of mGO increased the fracture toughness (G(IC_Resin)) of UPR and VER by as much as 49 and 35%, respectively, without lowering the modulus and glass transition temperature (T-g); however, the mode I interlaminar fracture toughness (G(IC_Comp)) of GFRPs was not improved. On the other hand, CSR is a more effective toughener, though at much higher loadings. 1 wt% had little effect, but 5 wt% of CSR enhanced G(IC_Resin) of UPR and VER by 280 and 600%, respectively, with a significant decrease in flexural modulus and flexural strength. 5 wt% of CSR was not able to increase the G(IC_Comp) of UPR laminates either; however, CSR did increase the initiation G(IC_Comp) and propagation G(IC_Comp) of VER laminates by 50 and 33%, respectively. Scanning electron microscopy of the fractured specimens revealed weak fiber-matrix bonding for all GFRPs. This work suggests that enhancing fiber-matrix bonding is critical to gain the benefit of adding nanoparticles to GFRPs. (C) 2018 Society of Plastics Engineers