中文摘要：

为研究纳米颗粒表面修饰对纳米二氧化硅/交联聚乙烯（SiO2/XLPE）电导电流和空间电荷特性的影响,分别将未经表面修饰和经钛酸酯偶联剂TC9修饰的纳米SiO2颗粒添加到XLPE基体中进行了实验.显微观测和成分分析表明,TC9的非极性有机官能团取代了纳米SiO2颗粒表面的羟基,降低了羟基间的相互成键作用,从而改善了纳米SiO2与XLPE基体之间的相容性,纳米SiO2颗粒在XLPE基体中的粒径范围从几十到100 nm;同时,TC9表面修饰提高了纳米SiO2/XLPE复合介质的介电常数和介质损耗,降低了电导电流,抑制了空间电荷的注入;而未经表面修饰的纳米SiO2/XLPE复合介质的电导电流和空间电荷特性相较于XLPE并未得到改善.分析认为,由于经TC9表面修饰的纳米SiO2分散性的改善,增大了纳米颗粒与XLPE基体之间的界面区域,因而在纳米复合介质内产生了更多的深陷阱;电极与介质界面附近的大量深陷阱捕获注入的电荷,形成固定的空间电荷层,降低了其与电极间的局部电场,从而提高了注入势垒,抑制了空间电荷的进一步注入.

英文摘要：

In order to study the influence of nanoparticle surface modification on conduction current and space chargecharacteristics of nano silica/cross-linked polyethylene（SiO2/XLPE） nanocomposites, we tested some XLPE nanocompo-sites mixed with unmodified SiO2 nanoparticles and those modified by TC9 titanate coupling agent, respectively. It isfound that the non-polar organic functional groups of TC9 coupling agent will substitute hydroxyls on the surface of SiO2nanoparticles, which reduces the interaction effect between hydroxyls and enhances the compatibility between nanopar-ticles and XLPE matrix. As a result, the TC9 coupling agent improves the SiO2 nanoparticle dispersion with thenanoparticle diameter ranging from tens to a hundred of nanometers. Meanwhile, it is found that the nanoparticle surfacemodification increases the relative permittivity and dielectric loss, decreases the conduction current, and suppresses thespace charge injection. On the contrary, UN-SiO2/XLPE nanocomposites even have worse conduction current and spacecharge characteristics compared with XLPE. The introduction of TC9-SiO2 nanoparticles into XLPE increases the inter-face area between the nanoparticle and XLPE matrix due to a better dispersion of SiO2 nanoparticles, which producesmore deep traps to capture injected space charge. The immobile homocharges near the electrodes decrease the local elec-trical field, forming permanent charge layers, and increase the charge injection barrier height, which further suppresses thespace charge injection.