五层纳米SiO2-Al2O3/聚酰亚胺复合薄膜的制备及性能

采用浸胶法制备了一系列SiO₂-Al₂O₃/聚酰亚胺（SiO₂-Al₂O₃/PI）五层耐电晕薄膜A_m A_n PA_n A_m，其中中间层（P）为纯PI薄膜，外层（A_m）、次外层（A_n）分别为SiO₂-Al₂O₃掺杂不同质量分数的纳米SiO₂-Al₂O₃/PI薄膜。采用TEM、FTIR、宽频介电谱仪、电导电流测试仪、耐电晕测试仪、介电强度测试仪和拉伸实验机对五层纳米复合PI耐电晕薄膜的微观结构、介电性能和力学性能进行了表征和测试。结果表明，SiO₂-Al₂O₃/PI复合薄膜掺杂层形成了分布均匀的有机/无机复合结构；SiO₂-Al₂O₃纳米粒子的保护作用是影响复合材料耐电晕性能的主要因素，复合薄膜A₃₂A₁₆PA₁₆A₃₂的耐电晕寿命最大，为23.4 h；外层掺杂量对五层SiO₂-Al₂O₃/PI复合材料的介电强度影响较大，复合薄膜A₂₀A₂₈PA₂₈A₂₀的介电强度最大，为302.3 kV/mm；通过对五层复合结构的设计，可以在兼顾材料力学性能的同时，提高其耐电晕寿命和介电强度。

Preparation and properties of five layer nano SiO2-Al2O3/polyimide composite film

A series of nano SiO₂-Al₂O₃/polyimide(SiO₂-Al₂O₃/PI) of five layer structure corona resistant film A_m A_n PA_n A_m were prepared by dipping method, the middle layer (P) was pure PI film, the outer layer (A_m) and the secondary layer (A_n) were nano SiO₂-Al₂O₃/PI composite film doped with different SiO₂-Al₂O₃ mass fraction. The microstructure, dielectric properties and mechanical properties of five layer nano SiO₂-Al₂O₃/PI composite film were characterized by TEM, FTIR, broadband dielectric spectrometer, conduction current tester, corona resistance tester, dielectric strength tester and tensile test machine. The results show that the organic/inorganic composite structure is formed in the doped layer of five layer nano SiO₂-Al₂O₃/PI composite film. The protection of SiO₂-Al₂O₃ nanoparticles is the main factor affecting the corona resistance of five layer nano SiO₂-Al₂O₃/PI composite film, and the corona resistant life of five layer nano SiO₂-Al₂O₃/PI composite film A₃₂A₁₆PA₁₆A₃₂ is the most, which is 23.4 h. The amount of doping in the outer layer has a great influence on the dielectric strength of the five layer composite, the dielectric strength of the composite film A₂₀A₂₈PA₂₈A₂₀ is the largest, which is 302.3 kV/mm. By designing composite structure of five layer film, the mechanical properties of the five layer nano SiO₂-Al₂O₃/PI composite film can be improved as well as the corona resistant life and dielectric strength of the material.