Effect of Interfacial Trap on Surface Insulation Properties of ZnO/PI Composite Films Under Cyclic Thermal Aging

WU Jiang ^1,2 ,WANG Tingyu ^1,2 ,WANG Xiaomin ^1,2 ,GUO Jianhua ^1,2 ,ZHANG Bo ^1,2 ,SHANG Penghui ³

（1. School of Electronics and Information，Xi’an Polytechnic University，Xi’an 710048，China； 2. Xi’an Key Laboratory of Interconnected Sensing and Intelligent Diagnosis for Electrical Equipment，Xi’an 710048，China； 3. Yangtze Delta Region Institute (Huzhou)，University of Electronic Science and Technology of China，Huzhou 313001，China ）

Abstract: Polyimide (PI) film is widely used as a solid insulating material with excellent properties，however，the degradation of surface insulation properties of PI nanocomposite films after cyclic thermal aging is still a lack of micro-interface explanation. Nano-ZnO/PI composite films doped with different mass fractions (0，1wt%，2wt%，3wt%) ZnO nanoparticles were prepared by in-situ polymerization method. Secondly，the flashover voltage，surface conductivity and trap distribution characteristics of PI film and 2wt%ZnO/PI composite film after aging were measured by cyclic thermal aging experiments at -40-150 ℃. The results show that the flashover voltage of PI films and ZnO/PI composite films decreases with the increase of cyclic thermal aging time，but the flashover voltage of ZnO/PI composite films decreases more sharply. Cyclic thermal aging can increase the shallow trap density and decrease the deep trap density of both materials，but the deep trap energy level of ZnO/PI composite films increases while the deep trap energy level of PI films decreases. The analysis shows that the increase of shallow trap density and the decrease of deep trap density lead to the decrease of carrier trapping probability and the increase of surface conductivity，which leads to the decrease of flashover voltage. From the perspective of interface analysis，cyclic thermal aging destroys the two-phase interface structure of ZnO/PI composite films，along with the enhancement of the conductivity process，the flashover voltage decreases more significantly than that of PI film.Keywords: cyclic thermal aging；polyimide；nano ZnO；interface；trap

引用本文： 乌江，王廷玉，王晓敏，等.循环热老化下ZnO/PI复合薄膜界面陷阱对表面绝缘性能的影响[J].工程塑料应用，2025，53(2)：83-91. (WU Jiang，WANG Tingyu，WANG Xiaomin，et al. Effect of interfacial trap on surface insulation properties of ZnO/PI composite films under cyclic thermal aging[J]. Engineering Plastics Application，2025，53(2)：83-91.)

通讯作者：乌江，博士，副教授，硕导，主要研究方向为极端环境下聚合物介质充放电效应与放电抑制技术

基金信息： 陕西省科技厅自然科学基础研究重点项目(2022JZ-35)，湖州市自然科学资金项目(2023YZ-04)

中图分类号： TM215.1TM855

文章编号：（）

文献标识码： A

收稿日期：2024-11-28

出版日期：2025-02-10

网刊发布日期：2025-03-12