加成型硅橡胶的制备与耐热稳定性的研究

采用乙烯基硅油为基胶，含氢硅油为交联剂，苯基硅油和氧化铁为耐热添加剂，制备了加成型耐热硅橡胶。研究了苯基硅油中苯基质量分数、苯基硅油用量、氧化铁用量及协同效应对硅橡胶耐热稳定性的影响。结果表明，随着苯基硅油、氧化铁用量和苯基质量分数的增加，硅橡胶的热稳定性明显增强；当苯基质量分数为10．2％，苯基硅油用量为10份，氧化铁用量为6份时，制得了耐热稳定性良好的硅橡胶，经300℃老化48h后，硬度和拉伸强度分别仅下降了3．77％和13．3％，而未改性硅橡胶老化后分别下降55％和79．3％。TGA结果显示，在苯基硅油和氧化铁协同保护作用下，硅橡胶在400。C高温前，热分解速率很低，这种协同保护效应能很好地提高耐热稳定性。

Preparation and Study on Heat-resistant Stability of Addition Curing Thermal Conductive Silicone Rubber

Heat-resistant silicone rubber was prepared with terminal vinyl silicone oil as matrix, hydrogen silicone oil as crosslinking agent, phenyl silicone oil and iron oxide as heat resistant addi- tives. The effect of the mass ratio, amount of phenyl silicone oil, the amount of iron oxide and coordi- nated protective on heat-resistant stability of the silicone rubber were studied. The results showed that with the increase of the mass ratio, amount of phenyl silicone oil and amount of iron oxide, the heat-resistant stability of the silicone rubber was improved. When the mass ratio of phenyl silicone oil was 10.2~, the amount of phenyl silicone oil was 10 phr, and the amount of iron oxide was 6 phr,the heat-resisting silicone rubber was prepared which hardness and tensile strength just reduced 3.77% and 13.3% respectively ,after 48 hours aging at 300℃, the hardness and tensile strength of the un- modified silicone rubber was reduced 55 % and 79.3 % respectively. The results of TGA showed that the rate of degradation was the lowest between the room temperature and 400 ℃ when the silicone rub- ber was under the coordinated protective effect of phenyl silicone oil and iron oxide. The coordinated protective effect could improve greatly the heat-resistant stability of the silicone rubber.