Physical, mechanical and environmental stress cracking characteristics of epoxy/glass fiber composites: Effect of matrix/fiber modification and fiber loading

Modified epoxy composites reinforced with various glass fiber contents up to 12 wt% were prepared by a simple fabrication method which involved mechanical stirring, hot pressing and post-curing. The effects of matrix modification with liquid epoxidized natural rubber (LENR) and fiber treatment with silane coupling agent on the physical, mechanical and dynamic thermal properties were examined. The modified epoxy composites had reduced density, water resistance and hardness. When compared to untreated glass fiber, the epoxy/LENR composites containing treated fiber exhibited improved water resistance and hardness property with comparable composite density. At 9 wt% of treated fiber, it revealed the highest hardness value of 65.6 and reduced diffusion coefficient of 2.2013 × 10−7 mm2s−1. The excellent storage modulus and interfacial adhesion (lower Tan δ) were obtained for treated glass fiber composites. Based on environmental stress cracking resistance evaluation under corrosive mediums, the fiber treatment had positively contributed to the degradation mechanism. •Modified epoxy was mechanically stirred with glass fiber before pressing and curing.•Toughening of epoxy with LENR and fiber treatment improved water resistance of composite.•Fiber treatment with silane improved the interfacial adhesion and composite stiffness.•The environmental stress cracking resistance of composites was enhanced with the treated fiber.•The optimum glass fiber was 9 wt% with the hardest characteristic.