氧化铁对复合绝缘子用高温硫化硅橡胶性能的影响

Influence of Fe_2O_3 on Properties of High-temperature Vulcanized Silicone Rubber for Composite Insulators

复合绝缘子的伞裙和护套是由高温硫化(HTV)硅橡胶制成的,其常用的红色着色剂为氧化铁(Fe2O3)粉体,属于无机物,在有机物硅橡胶中不易均匀分散。为探讨氧化铁对硅橡胶硫化性能的影响,采用不同氧化铁添加方式制备了含有不同用量氧化铁的硅橡胶试片,测定了试片的硫化曲线。然后通过热空气老化试验,结合试片的机械性能、电气性能和微观形貌测试结果,讨论了着色剂氧化铁在热空气环境中对硅橡胶试片性能的影响。试验结果表明:硫化过程中Fe+3和氧化铁表面的酸根离子消耗自由基,使硫化程度降低,因此氧化铁用量越多,试片刚性越差;将氧化铁预先制备成色母胶,在炼胶过程中添加,可以显著提高氧化铁粒子在试片中的分散性,进而在热空气环境中体现氧化铁耐热添加剂的作用,减缓试片因热氧老化造成的性能下降。

The sheath and shed of composite insulator are made of high temperature vulcanized（HTV） silicone rubber, which is normally colored red using ferric oxide powder as the colorant. Since ferric oxide powder is inorganic, it cannot disperse evenly in the rubber. Therefore, to investigate the influence of ferric oxide on vulcanization of silicone rubber, we prepared silicone rubber specimens with different concentrations of ferric oxide through different adding ways, and tested their vulcanization curves. Through hot air aging tests, we measured the changes of their electrical performances, mechanical properties, and microstructure, and hence discussed the influences of ferric oxide in these changes. The results show that, in the vulcanization processes, Fe＋3 and radical irons on the surfaces of iron oxide particles consume radicals, which decreases the vulcanization degree. Therefore increasing the content of iron oxide decreases the stiffness of the specimens. If the color master batch with ferric oxide was prepared and added into silicone rubber during its preparation, the dispersion of ferric oxide in the rubber and the rubber＇s heat aging performance would greatly improved due to the effect of ferric oxide heat-resistant addictive in hot air conditions.