二氧化硅/聚酰亚胺纳米复合薄膜的制备与性能研究

The Preparation and Performance Testing of Nano-organic-silica/PI Composite Film

采用溶胶-凝胶法,以苯基三乙氧基硅烷(PTES)为前驱体制备了氧化硅溶胶,并以均苯四甲酸二酐(PMDA)和4,4’-二氨基二苯醚(ODA)为原料,用原位生成法制备了一系列不同掺杂量(质量分数)的PI/SiO2复合薄膜。分别采用热失重分析仪(TGA)、扫描电镜(SEM)、耐电晕测试装置和耐击穿测试装置对薄膜的热性能、电性能进行了测试。结果表明,掺杂量为15%时纳米氧化硅粒子在PI基体中分散均匀,掺杂量为10%,热分解温度达到最大值,并且在工频50 Hz,场强为60 MV/m的室温条件下,掺杂量为15%时复合膜的耐电晕时间最长为55.73 h,电气强度为327 MV/m高于纯膜。

A silica sol was prepared using phenyltriethoxysilane（PTES） as the precursor by sol-gel method.Based on 4,4＇-oxydianiline（ODA） and pyromellitic dianhydride（PMDA）,a sequence of different doping（mass percent） nano-organic-silica/PI composite films were obtained via in situ polymerization.The thermal properties of the composite films were tested through TGA.The composite films＇ surface was observed by scanning electron microscopy（SEM）.Also,the composite films＇ electrical properties were tested by corona discharge measuring equipment and breakdown strength measuring system.The SEM micrographs indicate that the SiO2 particles are homogenously dispersed in the polyimide matrix.The thermal stability of the pure PI film can be improved by adequate addition of SiO2.It reaches a maximum when doped with 10% of SiO2.When the doping amount of SiO2 reaches 15wt%,the corona-resistant aging life is 55.73 h under 50 Hz of power frequency and 60 MV/m of electrical field strength at room temperature.It＇s longer thanthat of pure films.At the same time,the breakdown strength of the composite films is 327 MV/m,which is higher than that of pure films,too.