聚合物/无机填料非线性复合绝缘介质介电特性及其机理研究

项目名称： 聚合物/无机填料非线性复合绝缘介质介电特性及其机理研究

项目编号： No.50877019

项目类型： 面上项目

立项/批准年度： 2009

项目学科： 金属学与金属工艺

项目作者： 李忠华

作者单位： 哈尔滨理工大学

项目金额： 35万元

中文摘要： 本研究对聚合物添加非线性无机填料制备的非线性绝缘电介质的交、直流介电特性进行了系统的实验研究和理论研究。 在非线性复合绝缘直流介电特性研究方面：大量实验研究探明无机填料粒径、填充浓度以及温度对复合绝缘电介质非线性的影响规律。发现纳米无机复合材料相比微米复合材料在相同填充浓度下具有更明显的非线性；同时复合材料填料浓度特性具有明显的渗流阀值现象。结合复合材料微观结构和大量电导特性实验结果，借鉴氧化锌非线性电导的二步导电输运机理，建立了非线性复合材料非线性直流电导的三步导电输运物理模型，并推导出复合材料电导率与填料粒径、填充浓度、温度及电场强度的理论公式。 在非线性复合绝缘交流介电特性研究方面：提出了全面表征非线性复合绝缘电介质交流介电特性的方法，在该方法中阻性j-E特性和容性D-E极化特性曲线为基本特性曲线，由基本特性曲线可得动态、静态介电参数与电场关系曲线以及等效介电参数；实验探明非线性复合绝缘交流介电特性及相关影响规律；发现低填充浓度复合材料具有"动态负电导"和电导及介电常数的"负温度效应。通过非线线性绝缘介质交流介电特性研究结果推断非线性填料与聚合物基体微观界面的夹层极化。

中文关键词： 非线性绝缘电介质；复合材料；介电特性；电导机理；极化机理

英文摘要： The DC and AC dielectrical properties of the nonlinear insulating dielectrics made from polymer filled with nonlinear inorganic fillers are systemical researched through experiment and theory in this study. Study on DC dielectrical property of nonlinear insulating dielectrics: The effects of temperiture, the effect of size and concentration of filler on nonlinear conductivity of composite dielectrics and the related mechanisms are investigated experimentally. It is found that the conductance nonlinearity degree of the composites filled with nano-filler is higher than the composites filled with micro-filler, and there is a threshold concentration values for the filler concentration effect on the nonlinear conductance. Combining the microstructure of nonlinear composies and the experiment results on conductance property of nonlinear composite, and refering to the nonlinear conductance mechanism of ZnO, a physic mode of the nonlinear DC conductance mechanism of nonlinear insulating dielectrics is set up. And the physic formula is deduced, in the formula nonlinear conductivity is the function of electric field,temperature,size and concentration of filler. Study on AC dielectrical property of nonlinear insulating dielectrics: A comprehensive method to describe the character of nonlinear insulating dielectrics under AC electric field is put forward,in which the resistance j-E curve and the D-E curve are defined as the basic characteristic curves. And the dynamic and static conductivity and permittivity curve with electric field and equivalent dielectric parmeters can be obtained from the bsic characteristic curves. The nonlinear dielectric property of insulating composite under AC electric field are investigated through experiments.It is found that the nonlinear insulating composites with low concentration of filler shows the Negative Dynamic Conductance Phenomenon and the Negative Temperature Coefficient of Conductance. Form research results on the non-linear dielectric under AC field, it is deduced that the micro-interface polarization between the non-linear fillers and polymer matrix is the main polarization mechanism of for nonlinear nsulating composites.

英文关键词： nonlinear insulating dielectrics; composite materials; dielectrical property;conductanc mechanism;polarization mechanism