乙烯基含量对硅橡胶硫化特性的影响

Effect of vinyl concentration on the characteristics of silicone rubber vulcanization

采用动态热机械分析仪RSA3测试硅橡胶混炼胶的硫化特性,在非等温和等温条件下对硅橡胶硫化历程进行研究,探讨了不同温度条件和不同乙烯基含量硅橡胶体系的硫化特性及硫化动力学特征。同时,利用差示扫描量热仪(DSC)对硅橡胶硫化反应热力学作用进行了研究。结果表明,随着乙烯基含量的增加,混炼胶的交联密度提高,性能得到提高。在硫化过程中,硅橡胶硫化曲线都是呈现上升的趋势,是两个阶段的一级动力学反应过程,并且具有两个不同反应速率常数。硫化反应活化能随着体系中乙烯基含量的增加逐渐减小,反应活性提高。

The vulcanizing characteristics and kinetics of silicone rubber have been investigated by a dynamic mechanical thermal analyzer called RSA3.The effects of vinyl concentration and temperature on the vulcanizing characteristics and kinetics of silicone rubber have been discussed.At the same time,the vulcanizing thermodynamics of silicone rubber has also been studied by using differential scanning calorimeter（DSC）.The results indicate that,the crosslink density increases with the increasing vinyl concentration,and the storage modulus presents an uptrend.The mechanical properties are also improved largely due to the high crosslink density.Concluded from the results,the process of the vulcanization can be treated as two stages expressed in two first-order kinetics equations,and the activation energy can also be figured out with Arrhenius equation.The activation energy decreases with the increasing vinyl concentration of silicone rubber.