摘要
对于长期运行在潮湿环境中的风机和牵引电机,其绕组绝缘—聚酰亚胺薄膜极易因吸水而导致绝缘性能降低或过早失效,使系统发生绝缘故障。因此有必要研究聚酰亚胺薄膜的吸水特性及吸水之后聚酰亚胺薄膜的电气强度和表面电荷的动态变化规律。表面氟化作为一种材料表面改性方法,可以通过改变聚合物表面的化学组成而提高聚合物绝缘的整体性能。针对聚酰亚胺薄膜分别进行时间为0、15、30、45和60 min的表面氟化处理,并对氟化后聚酰亚胺薄膜的吸水特性及吸水后其相对介电常数、击穿电压和表面电荷动态特性进行研究。实验结果显示:聚酰亚胺薄膜的吸水率随着表面氟化处理时间的增加逐渐减小,试样的相对介电常数由于吸水率增加而随之增大,当氟化时间为45 min时,试样的相对介电常数最小;表面氟化处理提高了聚酰亚胺薄膜浸水后的击穿电压和表面电荷消散时间。研究结果表明聚合物表面氟化处理能够提高聚酰亚胺薄膜在潮湿环境中的绝缘性能,并为其工程应用提供了有效改性方法。
Polyimide （PI） film presents easily water absorption in wind turbines and traction motors because of long-term operation in moisture circumstances, thus the insulation properties decrease and irremediable damage will appear in the insulation system. Therefore, it is necessary to study the water absorption behaviors of the PI films and the dynamic changes of the electrical strength and surface charge of moistened PI film by changing the chemical composition of the polymer. Surface fluorination,regarded as a material surface modification method, can effectively improve the electrical properties of insulation. The PI film specimens were fluorinated for 0, 15, 30, 45 and 60 minutes. The water absorption, relative dielectric constant, breakdown strength, and surface charge behavior of the fluorinated PI films under different immersion time were measured. The results show that the water intake capacity decreases with the fluorination time and dielectric constant increases with the water absorption. The dielectric constant becomes the lowest with 45 rain fluorination. Meanwhile, the breakdown strength and surface charge decay time of PI in moisture conditions are enhanced by fluorination. Generally, surface fluorination has been proved to be an effective method for improving the electrical properties of PI film considering the application in moisture conditions.
出处
《高电压技术》
EI
CAS
CSCD
北大核心
2016年第9期2943-2949,共7页
High Voltage Engineering
基金
国家自然科学基金(51277131
51537008)
国家重点基础研究发展计划(973计划)(2014CB239506)~~
关键词
表面氟化
聚酰亚胺薄膜
潮湿环境
吸水率
击穿电压
表面电荷
surface fluorination
polyimide films
moisture circumstances
water absorption
breakdown voltage
surface charge
