交联度对XLPE/OMMT纳米复合材料水树枝老化特性的影响  

Effect of Crosslinking Degree on Water-Tree Aging Characteristics of XLPE/OMMT Nanocomposites

作　　者：董芸滋 高嫄 李秀峰[1] 董瑞雪 刘正第 韩圣斌 DONG Yunzi;GAO Yuan;LI Xiufeng;DONG Ruixue;LIU Zhengdi;HAN Shengbin(School of Electrical&Electronic Eng.,Shandong Univ.of Technol.,Zibo 255000,China)

机构地区：[1]山东理工大学电气与电子工程学院,山东淄博255000

出　　处：《工程科学与技术》2023年第4期79-88,共10页Advanced Engineering Sciences

基　　金：山东省自然科学基金项目(ZR2019MEE100);淄博市张店区校城融合发展计划项目(2021JSCG0009)。

摘　　要：电力系统日益提升的电压等级和复杂的运行环境,对电缆绝缘材料提出更多、更高的要求,工作在潮湿和强电场的极端环境下的绝缘材料应具有优越的电气、热和力学性能。而聚合物基纳米复合电介质以其独特的结构和优异的电气、力学及化学等性能获得了广泛关注。纳米复合材料的性能依赖于纳米粒子与交联所形成的微观结构形态的稳定性,为了从微观结构角度研究交联度对纳米复合材料水树枝老化特性的影响,通过调控交联时间,制备了两种不同交联度的交联聚乙烯/蒙脱土(XLPE/OMMT)纳米复合材料,并进行了加速水树枝老化实验。通过偏光显微镜观察水树枝形貌,统计水树枝长度和引发概率,并通过测试凝胶含量表征纳米复合试样的交联度;利用傅里叶红外光谱(FTIR)分析老化前后试样的化学组成变化,计算表征纳米复合试样老化程度的羰基指数和亚甲基指数;借助扫描电子显微镜(SEM)对比老化前后、水树区和非水树区结晶形态的变化,研究水树枝生长对晶体结构的破坏。结果表明:纳米复合材料的交联度影响了水树枝的引发概率,正交联状态下试样的水树枝形貌稀疏,分形维数和占空比小;试样老化过程中存在电化学降解现象,羰基基团增多;适当的交联度,可以使3维网状结构更加完善,试样的晶体尺寸差异性减小,晶体分布均匀,且老化后晶体破坏程度降低。有机化蒙脱土(OMMT)片层与基体之间形成牢固的界面作用力,增强了分子链韧性,且OMMT的屏障效应与完善的交联网络共同作用阻碍了水分子的扩散和聚集,抑制了微观水隙的产生,提高了纳米复合材料的耐水树枝能力。The increasing voltage level and complex operating environment of power systems have placed more and higher demands on cable in-sulation materials.The insulation materials should have superior electrical,thermal and mechanical properties when working in extreme environ-ments with moisture and strong electric fields.The polymer-based nanocomposite dielectric has gained much attention for its unique structure and excellent electrical,mechanical and chemical properties.The performance of nanocomposites depends on the stability of the microstructure mor-phology formed by nanoparticles and crosslinking.In order to investigate the effect of crosslinking degree on the water-tree aging characteristics of nanocomposites from the microstructure aspect,two kinds of crosslinked polyethylene/montmorillonite(XLPE/OMMT)nanocomposites with different crosslinking degrees were prepared in this paper by regulating the crosslinking time,and the accelerated water-tree aging experiment was conducted.Firstly,the water-tree morphology was observed by the polarized light microscopy.The length and initiation probability of water trees were calculated,and the gel content was tested to characterize the crosslinking degree of the nanocomposites.Secondly,the changes of the chem-ical composition of the specimens before and after aging were analyzed by the Fourier Infrared Spectroscopy(FTIR).The carbonyl index and methylene index that characterize the aging degree of the nanocomposite specimens were calculated.Finally,the scanning electron microscope(SEM)was used to compare the changes of the crystal morphology in the water-tree area and the nonwater-tree area before and after aging.The damage of the water-tree growth to the crystal structure was also studied.The experimental results show that the crosslinking degree of nanocom-posites affects the initiation probability of water trees.The water-tree morphology of the specimens in the positive crosslinking state is sparse,whose fractal dimension and duty cycle is small.The electrochemical degrad

关 键 词：交联度 纳米复合材料 交联聚乙烯 有机蒙脱土 水树枝老化 

分 类 号：TM215[一般工业技术—材料科学与工程]