Synthesis of a novel hybrid sizing and the effects on properties of carbon fiber/isomeric polyimide composites

A novel modifier, γ-(phenylethynyl) imidepropyltriethoxysilane (PEIPTES) was synthesized to make modified SiO₂ precursor, and then the novel isomeric polyimide/SiO₂ hybrid sizing was prepared. The structure and properties of PEIPTES, the structure of novel hybrid sizing were characterized by element analysis, FT-IR and thermoanalysis. The results indicated chemical bond was produced between organic phase and inorganic phase in the sizing. Analysis by AFM illustrated that a layer with nano particles was formed on carbon fiber surface after treated by the novel hybrid sizing, roughness was increased and interface properties of composites would be improved. It was confirmed that the hybrid sizing increased ILSS of the carbon fiber/isomeric polyimide composites, the optimal content of SiO₂ was 5wt%. At the same time impact properties and thermal properties of the composites were both increased obviously.