纳米Al2O3对聚酰亚胺薄膜受潮后绝缘性能的影响机制  

Effect of Al2O3 Nanoparticles on Insulation Properties of Polyimide Films After Damp

作　　者：雷毅鑫 吴广宁[1] 杨雁[1] 张兴涛[1] 吴旭辉[1] LEI Yixin;WU Guangning;YANG Yan;ZHANG Xingtao;WU Xuhui(College of Electrical Engineering, Southwest Jiaotong University, Chengdu 610031, China;Qinan Power Supply Branch, State Grid Chongqing Electric Power Company, Chongqing 401420, China)

机构地区：[1]西南交通大学电气工程学院,成都610031 [2]国网重庆市电力公司綦南供电分公司,重庆401420

出　　处：《高电压技术》2019年第10期3231-3239,共9页High Voltage Engineering

基　　金：国家杰出青年基金(51325704);哈尔滨理工大学工程电介质及其应用教育部重点实验室开放基金(KF20151109)~~

摘　　要：为了研究纳米粒子对聚酰亚胺薄膜受潮后绝缘性能的影响,以聚酰亚胺普通薄膜和聚酰亚胺纳米薄膜为测试对象,对吸水前后的薄膜进行了耐电晕实验、击穿场强实验、介电损耗的测试,并用傅里叶红外光谱(Fourier transform infrared spectroscopy,FTIR)研究了不同吸水率下薄膜的化学结构变化。结果表明:随着吸水率的增加,薄膜的介电损耗也随之增加,纯膜和纳米膜的耐电晕时间都出现先增大后减小的现象,击穿场强则出现逐渐下降的趋势。通过FTIR图谱分析,聚酰亚胺薄膜在水分存在的情况下酰亚胺环分子链发生开环反应,生成许多小分子链和一些带离子基团的化合物,一方面增加了载流子的数量,加快电荷消散,抑制了局部电荷的积累;另一方面,水分吸收过多会令介质损耗增加,介电性能降低,使得薄膜绝缘性能下降。纳米膜由于纳米粒子的引入,水分子可在纳米膜的周围形成"水壳",增多了电荷的传输通道,令其耐电晕时间先增大后减小的趋势更为明显,同时水分子和PI分子链发生水解反应,使得纳米粒子与PI分子链之间的化学键断裂,降低了聚合物基体的稳定性,因此纳米膜的击穿场强下降得更加严重。In order to study the influence of nanoparticles on the insulation performance of polyimide film after damp, taking polyimide (PI) Film and polyimide nano-film as test objects, we performed the corona tests, the breakdown field strength tests, and dielectric loss tests on the film before and after water absorption . Fourier transform infrared spectros- copy (FTIR) was used to study the chemical structure changes under the different proportion of water absorption. The results show that, with the increase of water absorption, the dielectric loss will increase, and the corona resistant time of pure PI film and nanocomposite PI film will increase first and then decrease. The breakdown field strength of PI film will tend to gradually drop with the increase of water absorption. The FTIR images reveal that, in the presence of water, the imide ring opening reaction takes place, generating many short molecular chain and some ionic groups of compounds. On the one hand, the increased number of carriers speeds up the charge dissipation, inhibiting the accumulation of local charge;on the other hand, the absorption of water increases the dielectric loss and weakens the dielectric properties, de- grading the film insulation performance. Because the "water shell" may be formed around the nanoparticles from water molecules, the transmission channel of the charge will increase in the nanocomposite PI films. The tendency of nano- composite PI film's corona resistant time which increases first and then decreases is more obvious. At the same time, the hydrolysis reaction with the water molecules and the molecular chain of PI break the chemical bonds between nanoparti- cles and PI molecular chain, reducing the stability of the polymer matrix. Therefore, the breakdown strength of nanocomposite PI film drops seriously.

关 键 词：聚酰亚胺 傅里叶红外光谱 水解反应 耐电晕 击穿场强 

分 类 号：TM855[电气工程—高电压与绝缘技术]