甲基乙烯基硅橡胶的耐热改性研究

Study on Heat Resistance Modification of Methyl Vinyl Silicone Rubber

以甲基乙烯基硅橡胶为基胶,添加白炭黑、结构化控制剂、氧化铈等制得耐热硅橡胶。研究了硫化温度、硫化时间、硫化剂浓度等对硅橡胶力学性能的影响,结构化控制剂种类对硅橡胶耐热性的影响。结果表明,当硫化温度175℃、硫化时间9 min、硫化剂质量分数1.5%时,硅橡胶的硫化性能优异,其拉伸强度为7.1 MPa;当氧化铈用量为1份时,300℃下老化4 h后依然具有52%的拉伸强度保持率。在氮气保护下,当温度超过300℃时,硅橡胶内部发生甲基分解,当温度达到500℃时,发生主链降解。

A heat resistance silicone rubber was prepared with methylvinyl silicone rubber, fumed silica, structural control agent, and cerium oxide. The effects of curing temperature and time, the concentration of vul- canizing agent on the mechanical properties of silicone rubber were studied. The influence of the types of the structure control agents on the heat resistance of silicone rubber was discussed. Results show that the vulcani- zation performance of the silicone rubber is excellent when the curing temperature is 175~C, curing time is 9 rain and the amount of vulcanizing agent is 1.5 % , whose tensile strength is 7.1MPa. When the amount of ce- rium oxide is 1% ,the silicone rubber has tensile strength retention of 52% after aging at 300℃ for 4 hours. Under nitrogen protection, when the temperature exceeds 300℃, methyl decomposition happens in the silicone rubber;and the main chain degradation happens when the temperature is 500℃.