Preparation of epoxy/Nano-SiO₂ hybrid sizing and effects on the properties of carbon fiber composites

Epoxy/nano-SiO₂ hybrid sizing for carbon fiber surface was prepared through sol-gel reaction, the structure and properties of the sizing films were analyzed, and the effects of the sizing on the properties of composites were also investigated. First, epoxy resin was grafted by γ-isocyanatopropyltriethoxysilane to modify in situ nano-SiO₂ precursors, then epoxy/nano-SiO₂ hybrid sizing was made by using the modified nano-SiO₂ precursors. FT-IR, AFM and Thermoanalysis Instrument were employed to analyze the structure of modification in situ of nano-SiO₂ precursors, the micro-morphology and thermal properties of the sizing films. The results indicated that epoxy/nano-SiO₂ hybrid sizing was prepared successfully, SiO₂ particles dispersed in the hybrid sizing film homogeneously with nanoscale, the thermal properties of the hybrid sizing film were improved because of the introduction of nano-SiO₂. Carbon fibers were modified by the epoxy/nano-SiO₂ hybrid sizing to confirm that the hybrid sizing increased both ILSS and impact properties of the composites through the investigation of mechanical properties.