硅橡胶表层性能的直接氟化调控及相关机理研究

Silicone rubber, as outdoor insulation material, has suffered several decades of practical operation and has become the preferred material for the outdoor insulation of high voltage insulators. However, the pursuit has never stopped for further improvement of its properties and extension of its service life. In this research project, the surface layer of silicone rubber is chemically modified by direct fluorination to modulate its surface layer properties, and so as to achieve the ultimate purposes of the enhancement of pollution flashover performance of silicone rubber and the extension of its service life. For this purpose, surface fluorination of silicone rubbers is first investigated to reveal the correlation between the physicochemical characteristics and the fluorination conditions. And then the hydrophobicity and hydrophobicity migration, surface energy, and basic electrical properties of the surface fluorinated silicone rubbers are studied to determine the modulation of these properties of silicone rubbers by direct fluorination and the relevant mechanisms. Afterwards the investigations on the corona, ultraviolet and thermal aging properties and the chemical resistance of the fluorinated layer are performed to disclose the correlation between these properties and the physicochemical characteristics of the fluorinated layer. Further, the tracking and erosion properties, flame retardancy, pollutant accumulation characteristics, and water absorption and permeation properties are evaluated. Finally, the flashover performance of the fluorinated silicone rubbers and the combined effects of the fluorination and the loading of micro-and nano- particles on the surface layer properties of silicone rubbers will be investigated to obtain surface fluorinated micro-and nano- inorganic particles/silicone rubber composites with excellent outdoor insulation properties.

尽管硅橡胶作为户外绝缘材料已经受了几十年的实际运行考验、成为高压绝缘子外绝缘材料的首选，但其性能的进一步改善、寿命的进一步延长一直是人们所追求的。本课题拟通过直接氟化、化学修饰硅橡胶的表层，调控其表层性能、以达到提高硅橡胶绝缘的污闪性能和延长其使用寿命的最终目的。为此，本课题将首先研究硅橡胶的表层氟化修饰，揭示氟化层物化特征与氟化条件的关联。进而研究氟化硅橡胶的憎水性、憎水迁移特性、表面能和基本电学性能，确立氟化对硅橡胶的这些基本性能的调控作用和作用机理。然后研究氟化层的电晕、紫外和热老化性能及耐化学腐蚀性能，揭示这些性能与氟化层物化特征的关联。进一步评价氟化硅橡胶的电起痕和电蚀损性、阻燃性、积污特性及吸水和渗水特性。最后研究氟化硅橡胶的闪络特性、研究氟化与微纳米无机颗粒填充对硅橡胶性能的综合影响，以最终获得户外绝缘性能优异的表层氟化微纳米无机颗粒/硅橡胶复合材料。

尽管硅橡胶作为户外绝缘材料已经受了几十年的实际运行考验、成为高压绝缘子外绝缘材料的首选，但它实际应用时并非无问题、免更换，其性能的进一步改善、寿命的进一步延长一直是人们所追求的。为此，本课题通过直接氟化修饰硅橡胶的表层、调控其表层性能，以达到提高硅橡胶绝缘的户外使用性能和延长其使用寿命的最终目的。本项目主要开展了硅橡胶氟化层的结构完整性与硅橡胶配方的关联研究；硅橡胶氟化层的物化特征与氟化条件的关联研究；氟化层的润湿性和表面能及憎水恢复特性；硅橡胶氟化层的水汽阻挡性能；硅橡胶氟化层的基本电学性能；表层氟化硅橡胶的交流和直流闪络性能；表层氟化硅橡胶的耐电晕和耐电弧性能；表层氟化硅橡胶的紫外老化和热老化性能；硅橡胶的配方研究及表层氟化硅橡胶的电起痕和电蚀损性能。获得如下重要结论和结果：（１）硅橡胶的氟化绝非是氟原子“简单地”甲基的氢原子，许多甲基被氟原子直接替代，氟化过程中除了氟原子之外还有许多其它的活性物种；（２）三水合氧化铝（ATH）的填充不利于获得结构完整性的硅橡胶氟化层；（３）氟化会显著地提高硅橡胶最终憎水性、极大地降低其表面能；（４）由于表层致密度的提高，氟化能显著提高硅橡胶的水汽阻挡能力；（５）由于表面电传导性的合适增大，氟化能提升硅橡胶的闪络性能、尤其是直流闪络性能；（６）硅橡胶氟化层不仅对“干的放电”有好的阻碍，同时在“湿放电”下也具有高的耐电起痕和耐电蚀损性能；（７）ATH-free的具有较好的长期老化性能的硅橡胶配方有望替代传统的ATH填充的硅橡胶；（８）上面所有性能改善关联于氟化条件和硅橡胶材料本身。这些重要的结论和结果具有潜在的重要的实际应用价值、不仅具有科学意义。