缩合型室温硫化硅橡胶耐热性能的研究

采用单因素变量法研究了不同的生胶(107胶)分子量,硅烷交联剂、催化剂以及硅烷偶联剂对缩合型室温硫化(RTV)硅橡胶耐热空气老化的影响,并初步探讨了自制有机硅高沸树脂对RTV硅橡胶在空气中耐热性的影响。通过热重分析仪(TGA)表征了RTV硅橡胶的热失重。结果表明,催化剂对RTV硅橡胶的耐热性有很大影响。有机硅高沸树脂可适当提高RTV硅橡胶的耐热性能,且在一定范围内,RTV硅橡胶的最大热失重温度和最终残炭率均随高沸树脂添加量的增加而增加。耐热性较好的RTV硅橡胶组分为:较高分子量的107胶、正硅酸乙酯、氨丙基三乙氧基硅烷、钛酸丁酯,以及适量的有机硅高沸树脂。

Study on Heat Resistance of Condensation Type Room Temperature Vulcanized Silicone Rubber

The influence of different raw rubber （107#silicone rubber） molecular weight, silane cross-linking agent, catalyst and silane coupling agent on resistance to ageing by heat air of condensation type room temperature vulcanized （RTV） silicone rubber was investigated using single factor variable method. The effect of homemade high boiling organic silicon resin on the heat resisting property of RTV silicone rubber in the air was also discussed preliminarily. RTV silicone rubber was characterized using thermogravimetric analysis （TGA）. The results showed that the heat resistance of RTV silicone rubber was influenced significantly by catalysts, and its heat resistance could be raised using organic silicon high boiling resin. Both maximum thermo- gravimetric temperature and carbon residue rate of RTV silicone rubber increased with addictive amount of organic silicone high boiling resin increasing within limits. Condensation type RTV silicone rubber compositions with the better heat resistance comprise 107# silicone rubber with high molecular weight, tetraethoxysilane （TEOS）, aminopropyltriethoxysilane, tetrabutyl titanate （TBOT） and organic silicone high boiling resin.