The polysilcoxane containing p-silphenylene was synthesized through ring-opening polymerization and dehydration condensation. The Effect of proportion of raw materials

amount of catalyst and temperature on the yield of reaction and the content of phenylene on the thermal performance of siloxane were systematically studied in this article. And the structure of the polymer was characterized by fourier transform infrared spectroscopy(FT-IR) and hydrogen nuclear magnetic resonance(

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H NMR). Molecular weight characteristics and thermal stability of the silicone were characterized by gel permeation chromatography(GPC) and thermal gravimetric analysis(TGA)

respectively. The results show that polysilicone containing p-silphenylene unit has been successfully prepared with this method and its molecular weight is controllable and greater than theoetical value and polydispersity index is 1.33 to 1.45. The yield is reduced with the increase of BHB in precursors

whereas it is improved with the increase of catalyst and reaction temperature. The 10% weight loss temperature was increased from 352℃ to 477℃ in air when p-silphenylene unit content is 15.09% and p-silphenylene unit significantly improved polysilicone thermal stability at high temperature.