热致变色微胶囊环氧复合绝缘材料介电性能的研究  

Study on dielectric properties of thermochromic microcapsule epoxy composite insulation material

作　　者：黄小羽 王文婷 焦宇阳 冀然 高建 HUANG Xiaoyu;WANG Wenting;JIAO Yuyang;JI Ran;GAO Jian(State Grid Beijing Powercable Company,Beijing 100022,China;Xi′an Jiaotong University,Xi′an 710049,China)

机构地区：[1]国网北京电缆公司,北京100022 [2]西安交通大学,陕西西安710049

出　　处：《绝缘材料》2023年第11期41-46,共6页Insulating Materials

基　　金：国家电网公司科技项目(5500-202211398A-2-0-ZN)。

摘　　要：本文制备了热致变色微胶囊环氧树脂复合绝缘材料(TEP),并对其工频介电常数(ε_(r))、介质损耗因数(tanδ)以及直流电导率(σ)的温度特性进行分析。结果表明:复合绝缘材料介电常数的温度特性在70℃时存在拐点,当温度低于70℃时,ε_(r)随温度升高迅速增大;当温度高于70℃时,ε_(r)随温度的变化率显著下降。tanδ在温度为50~70℃内显著降低。而添加热致变色微胶囊可以有效降低复合绝缘材料的直流电导率。在热致变色温度区间50~70℃内,热致变色微胶囊内部会发生固液相变,这是导致ε_(r)和tanδ特殊温度特性的主要原因。在固液相变过程中,微胶囊内芯材的分子活性逐渐增强,使其随外电场转向极化所需克服的阻力减小,导致ε_(r)随温度升高迅速增大、tanδ显著降低。当微胶囊内芯材全部转变为液态后,其分子活性随温度变化程度减小,导致ε_(r)随温度的变化显著降低。A thermochromic microcapsule epoxy resin composite insulation material(TEP)was prepared,and its power frequency permittivity(ε_(r)),dielectric loss factor(tanδ),and DC conductivity(σ)were analyzed in this paper.The results show that the temperature characteristic of dielectric constant of composite insulation material has an infelction point at 70℃.When the temperature is lower than 70℃,ε_(r)increases rapidly with the increase of temperature.When the temperature is higher than 70℃,the change rate ofε_(r)with temperature decreases significantly.The tanδdecreases significantly when the temperature is 50−70℃.The addition of thermochromic microcapsules can effectively reduce the DC conductivity of composite insulation material.In the thermochromic temperature range of 50−70℃,the solid-liquid phase transition occurs inside thermochromic microcapsules,which is the main reason for the special temperature characteristics ofε_(r)and tanδ.In the solid-liquid phase transition process,the molecular activity of the core material in microcapsule increases gradually,and the resistance that it needs to overcome in the orientation polarization with the external electric field decreases,resulting in the rapidly increase ofε_(r)and the significant decrease of tanδwith the increase of temperature.When the core materials of microcapsule are fully transformed to liquid state,its molecular activity decreases with temperature,leading to the significant decrease ofε_(r)with temperature.

关 键 词：智能环氧绝缘 热致变色 介电常数 介质损耗因数 直流电导率 

分 类 号：TM215[一般工业技术—材料科学与工程]