以分子取向理论理解交联聚乙烯中水树在不同温度下的生长特性  

Toward Understanding the Characteristics of Water Tree Growth at Different Temperatures in XLPE Based on the Theory of Molecular Orientation

作　　者：周凯[1] 陶文彪[1] 赵威[1] 杨滴[1] 杨明亮[1] 

机构地区：[1]四川大学电气信息学院,成都610065

出　　处：《高电压技术》2014年第12期3665-3673,共9页High Voltage Engineering

基　　金：国家自然科学基金(51477106)~~

摘　　要：为了理解交联聚乙烯(XLPE)在不同温度下的水树生长特性,研究了不同温度下XLPE材料的水树生长行为并尝试进行了新的理论解释。使用XLPE薄片作为实验样本,分别进行了0℃、20℃、40℃和60℃温度下的水树加速老化实验。通过显微镜观察了水树形态,统计了不同温度下水树的尺寸,并以有限元电场仿真分析、分子动力学和高分子取向理论为基础,给出了高温和低温下水树不同生长特性的一种可能的解释。经过研究发现:从0℃温度开始,水树的生长速率随温度的升高而先减小后增大,其转折温度约为40℃;XLPE分子的热运动和取向行为可能共同影响不同温度下水树的生长特性,高温下水树的生长速率主要由分子热运动决定,低温下水树的生长速率主要由高分子链的取向行为决定。For further understanding the water tree growth in cross-linked polyethylene（XLPE） at different temperatures, we tested the growth and proposed a new possible explanation for the observed phenomenon. Using XLPE fossils as the samples, we conducted the tests of accelerated water-tree aging under 0 ℃, 20 ℃, 40 ℃, and 60 ℃, respectively, where the shapes of water trees were observed through optical microscope and the sizes of water trees were measured. Moreover, on the basis of finite-element electric field simulations and the theories of molecular dynamics and polymer orientation, we deduced the possible explanation for the different characteristics of water tree growth at different temperatures. The experimental results show that the rate of water tree growth decreases when the temperature rises from 0 ℃, before it begins to increase at the temperature about 40 ℃. It is concluded that the water tree growth is influenced by the thermal motion behavior and the orientation behavior of XLPE molecules jointly, while the water tree growth is mainly determined by the thermal motion at high temperatures, but by the behavior of molecule orientation at low temperatures.

关 键 词：交联聚乙烯 水树 高分子动力学 取向 温度 Maxwell应力 

分 类 号：O632.12[理学—高分子化学]