纳米ZnO改性环氧树脂复合材料绝缘特性研究

发布时间：2019-01-11 12:44

【摘要】：当局部承受的电场强度较大时,电力系统中的绝缘设备或部件容易发生局部放电现象,严重时甚至造成绝缘击穿,影响系统的安全稳定运行。为了改善环氧树脂绝缘材料的电气性能,本文以纳米ZnO改性双酚A型环氧树脂材料为研究对象,测试不同掺杂浓度下聚合物的直流电导、局部放电起始放电电压等绝缘特征参数的变化趋势:对比分析了纳米ZnO改善环氧树脂绝缘特性的作用机理。首先,实验制备了以双酚A型环氧树脂E-51为基体,湿法改性处理过的纳米ZnO粒子为填料,纳米粒子含量分别为Owt%、2wt%、5wt%、10wt%。、15wt%、20wt%、30wt%的纳米ZnO/环氧树脂复合材料试样。利用扫描电子显微镜观测试样内部微观结构,在确保所制备的试样内部纳米粒子与基体之间接触良好、并且没有发生明显团聚的前提下,按照国家标准制备测试样品,搭建电导特性、介电特性等电气性能测试平台,对比纯环氧树脂与不同掺杂浓度的聚合物电气性能参数,分析纳米ZnO粒子对环氧树脂的作用效果。其次,为了更好地探讨掺杂纳米ZnO粒子之后,环氧树脂复合材料出现|非线性电导特性的原因以及作用机理,制备与纳米ZnO相同粒径的纳米SiO2改性环氧树脂复合材料,实验对比了相同掺杂浓度下两种聚合物的直流电导、介电常数、局部放电起始放电电压、击穿场强等绝缘特征参数的变化趋势。分析实验结果可知,当纳米ZnO掺杂量大于15%质量分数时,复合材料具有显著的非线性电导特性:纳米ZnO掺杂量增大时,介电特性没有表现出非线性特性:掺杂ZnO纳米粒子的环氧树脂介质损耗随掺杂量的增加而增大,由纯环氧树脂的1.25‰最大升高至3.34‰; ZnO/EP复合材料在针板电极下,掺杂量为15%时起始局放电压达到最大值,比无掺杂树脂提高了 33%,比纳米SiO2掺杂树脂提高了 22%; ZnO/EP试样的击穿强度由未掺杂的31.5kV下降至23.8kV。综上所述,掺杂纳米ZnO粒子的环氧树脂的局部放电起始电压、介电常数、介质损耗较纯环氧树脂明显提高,而交流短时击穿场强纯环氧树脂有所降低;理论分析表明,纳米ZnO粒子的引入显著提高了环氧树脂复合材料的绝缘性能,纳米ZnO粒子的界面效应和非线性电导特性在改善复合树脂绝缘特性方面发挥了主要作用。另外,ZnO/EP复合材料当掺杂量大于15%质量分数时,复合材料具有显著的非线性电导特性,对针板电极系统下的不均匀电场有改善作用,有利于提高材料的抗老化能力。
[Abstract]:When the local electric field is strong enough, partial discharge is easy to occur in the insulation equipment or components of the power system, and even insulation breakdown occurs in serious cases, which affects the safe and stable operation of the system. In order to improve the electrical properties of epoxy resin insulating materials, the direct current conductance of polymers with different doping concentration was measured by using nanometer ZnO modified bisphenol A epoxy resin as the research object. The variation trend of insulation characteristic parameters such as partial discharge initial discharge voltage: the mechanism of nanometer ZnO to improve the insulation characteristics of epoxy resin was compared and analyzed. Firstly, ZnO nanoparticles modified by wet method were prepared with bisphenol A epoxy resin E-51 as matrix and nano-particles content as Owt%,2wt%,5wt%,10wt%.,15wt%,20wt%,. 30 wt% nanosized ZnO/ epoxy resin composites. Scanning electron microscope (SEM) was used to observe the microstructure of the samples. The test samples were prepared in accordance with the national standards without obvious agglomeration and good contact between the nanoparticles and the matrix. The electrical properties of pure epoxy resin and polymer with different doping concentration were compared, and the effect of nano-sized ZnO particles on epoxy resin was analyzed. Secondly, in order to better investigate the reason and mechanism of nonlinear conductivity of epoxy resin composites after doping nano ZnO particles, nano SiO2 modified epoxy resin composites with the same size as nano ZnO were prepared. The variation trends of dielectric parameters, such as DC conductance, dielectric constant, initial discharge voltage of partial discharge and breakdown field strength of the two polymers with the same doping concentration were compared experimentally. The experimental results show that when the content of nanometer ZnO is more than 15%, the composite has remarkable nonlinear conductance: when the doping amount of nanometer ZnO increases, The dielectric properties of epoxy resin doped with ZnO nanoparticles increased with the increase of doping content, from 1.25 鈥，

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