It is very important to develop a new method of preparing high-performance liquid silicone rubber-reinforcing filler. Herein, the hydrophilic surface of silica (SiO2) particles was modified by a vinyl silazane coupling agent to prepare a new type of hydrophobic reinforcing filler. The structures and properties of modified SiO2 particles were confirmed using Fourier-transform infrared spectroscopy (FT-IR), X-ray photoelectron spectrometer (XPS), specific surface area and particle size distribution and thermogravimetric analysis (TGA), the results of which demonstrated that the aggregation of hydrophobic particles is greatly reduced. Additionally, the effects of the vinyl-modified SiO2 particle (f-SiO2) content on the dispersibility, rheology, and thermal and mechanical properties of liquid silicone rubber (SR) composites were studied for application toward high-performance SR matrix. The results showed that the f-SiO2/SR composites possessed low viscosity and higher thermal stability, conductivity, and mechanical strength than of SiO2/SR composites. We believe that this study will provide ideas for the preparation of high-performance liquid silicone rubber with low viscosity.
Keywords: mechanical properties; silica; surface modification; thermal conductivity; thermal stability.