纳米银/环氧树脂复合电介质的电导特性

研究了纳米银(Ag)/环氧树脂(EP)复合材料的直流体积电阻率和强场电导。结果表明，在环氧树脂中微量添加小尺寸的银纳米粒子后，复合材料的体积电阻率比纯环氧树脂有明显提高，并且电阻率的增加与银粒子尺寸、含量，以及基体聚合物的特性有关。对复合材料强场电导的研究表明，小尺寸的银粒子在聚合物中分散良好时，复合物的强场电导表现出库仑阻塞特性，即纳米粒子可限制载流子的迁移。而当纳米粒子的粒径过大或添加较多时，复合材料在强电场下表现出对电荷的捕获与脱陷，具有明显的空间电荷限制电流特性。热刺激电流特性反映出纳米粒子与聚合物在界面处形成深陷阱是产生空间电荷限制电流的原因

Conductive Properties of Nano-Silver/Epoxy Resin Composite Dielectrics

The DC volume resistivity and high field conductivity of nano-Ag/epoxy resin polymer composite were researched. The results show after trace addition of Ag nanoparticles with small sizes, the composite has obviously higher volume resistivity than pure epoxy resin. The increase of resistivity is relative with Ag particle size, adding content and characteristics of base polymer. High field conductivity tests show that the coulomb blockade effect appears when Ag particles of small size disperse evenly in the polymer, i.e. the transmission of electron charge can be restricted by nanoparticles. When the adding content of Ag nanoparticles is too much or their size is too big, the composite shows space charge limited current property. TSC results show that more deep traps exist at the interface between nano Ag and polymer, which causes space charge limited current for charge captured and escaped from the traps