耐热硅树脂的合成与固化性能的研究

Research on synthesis and curing of heat-resistant silicone resin

以甲基苯基二氯硅烷、苯基三氯硅烷、甲基三氯硅烷、二甲基二氯硅烷为原料,在甲苯、丙酮和水组成的混合溶剂中水解;再经缩聚反应,制得无凝胶的硅树脂。研究了水解温度、搅拌速度以及溶剂等因素对水解反应的影响,并用IR、29SiNMR谱图表征了硅树脂的结构,研究了其耐热性及固化性能。结果表明,较佳的水解工艺是:n(R)/n(Si)=1·3,n(Ph)/n(Me)=1·0,m(丙酮):m(甲苯)∶m(水)=1∶2∶4,水解温度为60℃,搅拌器转速为2档;硅树脂在300℃×24h条件下的热失重率为3·07%,且颜色基本未变;该硅树脂以羟基封端,加入硅氮低聚物后,能在室温下固化,且固化时间不超过7天。

The heat-resistant silicone resin was synthesized through condensation polymerization of organochlorosilanes. The condensation polymerizing reaction conditions such as hydrolysis temperature, stirring rate and solvents were studied. The structure was characterized by IR and ~29Si-NMR spectra. The thermal properties of the silicone resins and curing system were studied. The result showed that the optimum hydrolysis technique was that n(R)/n(Si)=1.3,n(Ph)/n(Me)=1.0,m(acetone)∶m(toluene)∶m(H_2O)=1∶2∶4, hydrolysis temperature was 60 ℃, the rotating speed of agitator was the second gear, the silicone resin had good heat resistance. In the condition of 300 ℃×24 h, its heat rate of weight loss was 3.07% without the change of color. The silicone resin was OH terminal, after adding the SiN oligomer, it could be cured at room temperature not longer than seven days.