Effect of Silane Coupling Agent on the Tensile Properties of Carbon Fiber-Reinforced Thermoplastic Polyimide Composites

Silane coupling agent SG-Si900 (SGS) modification and air-oxidation methods were used to improve the interfacial adhesion of the carbon fiber-reinforced polyimide (CF/PI) composite. The interfacial characteristics of the composites reinforced by the carbon fibers treated with different surface modification methods were comparatively investigated. Results showed that both SGS modification and air-oxidation method improved the adhesion between the reinforcement and matrix and SGS modification method was superior to air-oxidation method. For CF/PI composite the optimum interfacial adhesion was obtained at 0.3 wt% SGS concentration. The fracture surfaces of samples were investigated by scanning electronic microscopy (SEM) to analyze the effects of different surface treatment methods.