高抗污耐电痕化硅橡胶的制备及其防污闪与耐漏电起痕作用机理研究

Rising voltage level and worsening air pollution seriously deteriorate the service performance of silicone rubber under the strong electric field and heavy contamination circumstances. The security and stability of the high voltage and extra high voltage power transmission are severely threatened by the contamination flashover and tracking. Recently, the major method to improve the tracking resistance of silicone rubber is by filling a great amount (> 50wt%) of inorganic fillers (such as aluminum hydroxide) into the rubber. However, it would deteriorate the mechanical properties, hydrophobic and anti-fouling performance of the silicone rubber. In this work, a reactive organic anti-tracking agent named urea-containing MQ silicone resin (U-MQ) is firstly synthesized by ureido silane and vinyl silane via hydrolytic polycondensation reaction. Secondly, a fluorine-containing low melting organic-inorganic hybrid glass (F-LMOIG) with good hydrophobic and anti-fouling performance is synthesized by phenyltriethoxysilane and fluorine silane via sol-gel process. Subsequently, the excellent anti-tracking silicone rubber with outstanding anti-fouling property is prepared by incorporating a small amount (<5wt%) of U-MQ and F-LMOIG into the additional-cured liquid silicone rubber. The effects of U-MQ and F-LMOIG on the anti-fouling performance and tracking resistance of the silicone rubber are investigated. Furthermore, the anti-contamination flashover and anti-tracking mechanism of the silicone rubber are systematically studied and revealed. Through this work, a new method and theory are provided for the design, preparation and application of the novel silicone rubber insulating material with high service performance in the harsh conditions.

不断提升的电压等级与日益恶化的大气污染严重损害硅橡胶在强电场重污秽环境下的服役性能，因其污秽闪络与漏电起痕破坏严重威胁高压超高压输变电路的安全与稳定。目前提高硅橡胶的耐漏电起痕性能主要依靠填充大量（>50wt%）的氢氧化铝等无机填料，存在力学性能及憎水防污性差等缺点。本项目通过脲基硅烷和乙烯基硅烷等共水解缩聚制备可反应性有机耐漏电起痕剂——含脲基MQ硅树脂（U-MQ）；采用苯基三乙氧基硅烷和氟硅烷通过溶胶-凝胶法制备含氟有机-无机杂化低熔点玻璃（F-LMOIG）；将较少量（<5wt%）的U-MQ和F-LMOIG引入加成型液体硅橡胶，制备高抗污耐电痕化硅橡胶绝缘材料。研究U-MQ和F-LMOIG对硅橡胶憎水防污和耐漏电起痕性能的影响；揭示U-MQ和F-LMOIG协同作用下硅橡胶的防污闪及耐漏电起痕作用机理，为严苛环境下高性能硅橡胶绝缘材料的设计、制备及应用提供新方法和理论依据。

如何有效提高硅橡胶的耐漏电起痕性能和憎水防污性，是当前高性能硅橡胶绝缘材料发展与应用亟需解决的关键问题。本项目合成了含脲基MQ硅树脂（U-MQ）和含氟有机-无机杂化低熔点玻璃（FPLMG），随后将其引入加成型液体硅橡胶（ALSR）中，制备了兼具优良加工性能、力学性能、防污闪性能和耐漏电起痕性能的硅橡胶绝缘材料。仅添加1.0 phr的U-MQ和2.0 phr的FPLMG，即可使ALSR通过耐漏电起痕测试1A 4.5级，且电蚀损质量仅为0.2%。项目系统研究了U-MQ和FPLMG对ALSR憎水防污性、耐漏电起痕性能及热解聚行为的影响，探讨了电弧放电过程中ALSR的化学结构及形貌变化，阐明了U-MQ对ALSR热分解行为的影响及其与耐漏电起痕性能之间的内在联系，揭示了U-MQ和FPLMG协同作用下ALSR的防污闪与耐漏电起痕破坏机理。FPLMG可以显著提高ALSR的憎水性能，阻碍污染液在其表面润湿；氟原子有利于硅橡胶表面的电荷耗散，抑制电弧的发生和发展。此外，FPLMG在电弧放电产生的高温作用下可在ALSR表面形成“玻璃”保护层，阻隔热量和氧气往ALSR基体中扩散。含氮硅烷与铂络合物可发生协同作用，有效抑制硅橡胶侧甲基的氧化，缓解硅橡胶解链式降解；在强电弧作用下催化大分子自由基交联，在硅橡胶表面形成致密的陶瓷阻隔层，有效保护内层硅橡胶免受电弧侵蚀，抑制电痕的产生和发展。另一方面，U-MQ和FPLMG复配可显著提高ALSR耐等离子体辐照性能，加速等离子体辐照后ALSR表面憎水性能的恢复，进一步改善硅橡胶的耐漏电起痕性能。本项目为严苛环境下高性能硅橡胶绝缘材料的设计、制备及应用提供了新方法和理论依据。在项目执行过程中，在ACS Applied Materials & Interfaces, Composites Part B, Applied Surface Science, Polymer Degradation and Stability和Polymer Testing等本领域国内外权威学术期刊上发表学术论文25篇（其中SCI收录24篇，EI收录1篇），获授权中国发明专利7件，参加全国学术会议并做与项目相关的报告6次，共培养博士生5名（已毕业2名）、硕士生5名（已毕业4名）。