中文摘要：

应用经硅烷偶联处理后的纳米氧化镁（MgO）粉末与低密度聚乙烯（10wdensitypolyethylene，LDPE）共混，制得MgO／LDPE复合介质。高成分衬度扫描电镜（scanningelectronmicroscope，SEM）@图像表明，粒径为100nlTl左右的MgO纳米粒子均匀的分散于介质中。通过电声脉冲法（pulsedelectro．acoustic，PEA）测试发现，当纳米MgO填料的质量分数为4％时，可以有效抑制空间电荷的注入，伏安特性的实验结果表明，复合介质拥有更高的空间电荷注入闽值场强。通过电树枝实验，发现复合介质可以抑制电树枝的引发和生长。最后，对实验结果进行了分析，探讨了纳米复合介质抑制空间电荷和树枝化生长的机制。纳米颗粒与基体材料界面电荷行为可能是复合介质电学性能改善的原因。

英文摘要：

Magnesium oxide （MgO）/low density polyethylene （LDPE） nano-composite was prepared by laboratory blending process after MgO nano-powder was treated by silane coupling agent. MgO particles with diameters of about 100nm were observed to be well dispersed in LDPE by means of high composition contrast scanning electron microscope （SEM） image. The results of space chargedistribution measurement by the pulse electro-acoustic （PEA） method revealed that the space charge injection of MgO/LDPE nano-composite was effectively suppressed at 4% MgO in the composite. Meanwhile, at this concentration of MgO, a much higher threshold of space charge injection was found in MgO/ LDPE nano-composite by the current voltage characteristic. Electrical treeing breakdown tests indicated a higher tree inception voltage and a restrained tree propagation process in the composite. Interracial electric charge in the boundary of the nano particles and the polymer matrix was suggested to be responsible for the improvement of electrical properties.