加成型液体硅橡胶耐电痕化及蚀损性能提升方法研究

Improving the Tracking and Erosion Resistance Performance of Addition-cure Liquid Silicone Rubber

加成型液体硅橡胶的耐电痕化及蚀损性能优化是外绝缘领域研究重点之一。该文分别改变气相法白炭黑质量分数及铂催化剂含量,制备A、B两个系列试样,采用斜面法测定各试样的耐电痕化性能,利用TG-FTIR-MS联用技术、扫描电镜,对比分析各试样的热分解产物、热稳定性及烧蚀面的微观形貌。结果显示,提高试样铂催化剂的含量及气相法白炭黑质量分数,均可提高试样的耐电痕化及蚀损性能,其中以前者效果更为显著。分析认为,环状二甲基硅氧烷低聚物分解生成是影响加成型液体硅橡胶耐电痕化及蚀损性能的重要因素;提高试样中气相法白炭黑质量分数,虽可以提高试样的热稳定性,但不足以抑制环状二甲基低聚物分解生成,以至于耐电痕化及蚀损性能提升效果有限;而将铂催化剂的含量从15ppm提高至30ppm后,硅氧烷的失重比例则由32.46%显著降至28.13%,试样的耐电痕化及蚀损性能等级则由1A2.5级提高至1A6.0级,表明提高铂催化剂的含量可抑制硅氧烷主链分解,从而大幅提升试样的耐电痕化及蚀损性能。

Improving the tracking and erosion resistance performance of addition-cure liquid silicone rubber （ALSR） is one of the most important research points in the field of external insulation. A- and B-series ALSR samples were prepared by changing the fumed silica mass fraction and platinum catalyst concentration, respectively. The arc resistance performances of all the samples were measured via Inclined Plane Test （according to IEC 60587）. The thermal decomposition products and thermal stability of the samples were analyzed by the thermogravimetry-Fourier transform infrared spectroscopy-mass spectrometry hyphenated technique. The morphology of the ablation residues were comparatively analyzed also. Results showed that increasing the concentration of platinum catalyst and the mass fraction of fumed silica improved the arc resistance performance, of which the former was more effective. Further analysis indicated that the formation of ODMS is an important factor affecting the tracking and erosion resistance performance. Increasing the fumed silica mass fraction can enhance the thermal stability, but it is insufficient to suppress the formation of ODMS, and thus the improvement effect is limited. In contrast, with increasing the concentration of platinum catalyst from 15ppm to 30ppm, the weight loss ratio of siloxane was obviously decreased from 32.46% to 28.13%, while the tracking and erosion resistance performance was elevated from 1A2.5 to 1A6.0. It means that increasing the concentration of platinum catalyst can effectively suppress the formation of ODMS, andthus improve the tracking and erosion resistance performance effectively.