中文摘要：

为了探究温度和湿度对掺杂纳米氧化铝的聚酰亚胺（PI）薄膜耐电晕性能的影响，文中通过原位聚合法制备了氧化铝粒径为20nm的聚酰亚胺／氧化铝（PI／Al2O3）复合薄膜，在高频方波脉冲下进行纯膜和纳米膜的耐电晕实验。运用扫描电镜对电晕老化前后的薄膜形貌进行分析。实验结果表明：同一电压下，纳米膜耐电晕性能优于纯膜。纳米粒子可改变电荷传输通道，并浮于聚合物表层阻挡进一步侵蚀。随着温度升高。聚合物降解产生的气体分布在基体中，易造成电场畸变而加剧侵蚀，导致薄膜寿命缩短；且纳米膜热导率高于纯膜．故高温环境中耐电晕性能较好。随着相对湿度增大，纳米膜耐电晕寿命先增大后减小，主要是因为相对湿度较低时，水分可在纳米粒子周围形成“水壳”，增大了纳米粒子间重叠区域，增加了电荷消散传输通道：而相对湿度较高时，聚酰亚胺分子水解产生大量离子基团及小分子，造成电场畸变加剧电晕侵蚀作用更大。

英文摘要：

To study the influence of temperature and humidity on corona resistance of polyimide （PI） doped with nano alumina （Al2O3） particles, PI/Al2O3 composite film is prepared by in situ method, then corona resistance test of pure PI film and PI/Al2O3 composite film under high frequency square voltage is conducted. The results show that PI/Al2O3 composite film performances better than pure PI film on corona resistance under the same voltage, because nano particles would float on the surface of film which can protect film from further erosion. In addition, polyimide would degrade and produce much gas distributing among polymer matrix, which resulting in distortion of electric field and shorten the life time of film as the increase of temperature. Because of PI/Al2O3 film higher thermal conductivity than pure PI film, PI/AI203 film shows better performance in high temperature environment. Furthermore, with the increase of relative humidity, the life time of corona resistance of PI/Al2O3 film would in- creases first and then decreases, it mainly because water molecule would surround nano particles and form ＂water shell＂, resulting in more transmission paths of charge emerges when relative humidity is low. While relative hu- midity is high, a lot of ions and little molecules produce due to hydrolysis of polyimide, which leads to distortion of electric filed and deterioration of erosion from corona.