Synthesis Of High-Tmeperature Resistant Hybrid Silicon Resin And Properties Of Its Composite

The flight match number of aircraft keeps increasing with the rapid develop-ment of aeronautic technology and the need of modern national defence. So the demand for the performance of radome materials is higher and higher. Because of its unique structure of the "semi-inorganic and semi-organic", silicone resin as a composite matrix has good thermal stability, dielectric property and physical inertia. As a particularly attractive and great potential resin matrix for composites, silicon resin has been valued by many researchers worldwide.In this research, we improved the heat-resistant performance by inducing different amount of TEOS into methyl silicon resin. In this system, TEOS is inorganic phase, and methyltrimethoxylsilane is organic phase. Organic-inorganic hybrid silicon resin was prepared by sol-gel processing. Besides, the gel property of silicon resin is inspected. The structural changes of silicon resin and modified resin by TEOS were characterized by fourier transform infrared spectroscopy (FT-IR), solid Si NMR (29Si-NMR), X-ray photoelectron spectroseopy (XPS), and so on. The thermal stability and thermal degradation mechanism at high temperature were studied by the means of TG , XPS and et al.The results show that heat decomposition temperature of modified methyl silicon resin was raised, and the thermal weight loss was decreased by adding TEOS. The heat tolerance and thermo oxidative stability of TEOS-modified methyl silicon resin were enhanced by inhibiting the thermal oxidation and degradation. The impact of TEOS on the thermal decomposition reaction kinetics of methyl silicon resin was studied by Ozawa method. The result shows that thermal degradation activation energy of TEOS-modified methyl silicon resin is higher than that of pure methyl silicon resin.Quartz fiber reinforced methyl silicon resin and TEOS-modified methyl silicon resin composites were prepared. The mechanical properties, such as flexural strength, interlaminar shear strength, multifilament tensile strength, at room temperature and after being treated at high temperature were tested respectively. The results manifest the mechanical properties of TEOS-modified methyl silicon resin/quartz fiber are higher than the unmodified ones after being treated by high temperature.The flexural fracture morphologies of methylsilicone resin/quartz fiber and different amounts of TEOS-modified silicon resin/quartz fiber composite materials at room temperature and after being treated by high temperature were compared through the monofilament pull-out experiments and scanning electron microscopy (SEM). The effect of TEOS's amount was studied on the interface performance of the composites. Besides, the interface performance of composites effected by different dosage of TEOS was also studied.