耐高温含氢乙烯基有机硅树脂的合成及改性OA北大核心

Silicone resin is a type of high-temperature-resistant material with excellent properties and exhibit broad application prospects in the field of heat resistance.With a rapid development of silicone resin for thermal protection coating in the na-tional defense industry,it is difficult to meet the current requirement of applications.Therefore,there is a great strategic val-ue to improve the high temperature resistance of silicone resin.Thermally stable vinyl silicone resin containing hydrogen was successfully prepared by a simple two-step method under acidic conditions using the alkoxysilanes containing silicon-hydro-gen and silicon-ethylene bonds as raw materials.The synthesis conditions of the modified silicone resin were investigated by infrared spectroscopy and thermogravimetry analysis,and its chemical structure,thermal stability,and thermal decomposi-tion mechanism by thermogravimetric Fourier transform infrared analysis.The results indicated that the synthesis conditions were determined to be a pH of 1.0,a hydrolysis temperature of 30℃,and a hydrolysis time of 3 h by using triethoxysilane and vinyl triethoxysilane as monomers and ethanol and hydrochloric acid as organic solvents.The as-synthesized silicone res-in obtained a char yield of 97.84%at 800℃when synthesized under the optimum conditions,and its high temperature resis-tance was far higher than that of the ordinary silicone resin.The thermal decomposition of the hydrogen-containing vinyl sili-cone resin included two stages:the first stage occurred at about 253 ºC due to the oxidative degradation of partial vinyl of side-linked branches of silicone resin;The second stage taking place at 578 ºC,which was caused by the random fracture and rear-rangement of SR skeletons due to the back reaction of silicone hydroxyl end groups of silicone resin.