Study on the Influence of Silane Coupling Agent Surface Modification on the Interfacial Properties of Glass Fiber Reinforced Nylon Composites

Poor interfacial compatibility in glass fiber reinforced nylon composites limits the full realization of their mechanical properties, with weak fiber-matrix bonding becoming a key bottleneck in engineering applications. This study uses γ-aminopropyltriethoxysilane to modify the surface of glass fibers and systematically investigates the effects of coupling agent concentration and treatment temperature on composite interfacial properties. APS concentrations of 0.5%, 1.0%, 1.5%, and 2.0 wt% and treatment temperatures of 80 ◦C, 100 ◦C, and 120 ◦C are examined. Scanning electron microscopy and Fourier transform infrared spectroscopy are used to characterize changes in fiber surface morphology and chemical structure, while single-filament tensile testing, monofilament pull-out testing, and interlaminar shear strength testing are used to evaluate interfacial bonding performance. Results show that as APS concentration increases from 0.5% to 1.5%, the Si-O-Si peak intensity increases by 108% and the N element content increases by 156%, indicating enhanced silane grafting. Excessive concentration leads to self-polymerization and reduced coating uniformity. The study clarifies the interfacial reinforcement mechanism of silane-modified glass fiber reinforced nylon composites.