微量SiO_2对PI/Al_2O_3复合薄膜性能的影响

The effects of trace amounts of SiO_2 on the properties of polyimide /Al_2O_3 composite films

通过固定纳米氧化铝(Al2O3)的含量,改变纳米氧化硅(SiO2)的含量,制备一系列纳米SiO2含量不同的聚酰亚胺(PI)/Al2O3/SiO2复合薄膜。采用扫描电子显微镜(SEM)和红外光谱(FT-IR)对复合薄膜的微观形貌和分子结构进行表征,结果表明纳米颗粒在PI基体中均匀分散,而且纳米颗粒的加入既不影响PI的分子结构又对聚酰胺酸的热亚胺化无影响。同时测试了薄膜的力学性能、击穿场强和耐电晕时间。结果表明,当纳米SiO2质量分数为0.5%时,复合薄膜的击穿场强和耐电晕时间分别为211.15 kV/mm、378 min,均优于纳米SiO2质量分数分别为0,0.1%,0.3%和0.7%的薄膜,并且其力学性能也较优异。

In this paper,the polyimide （PI）/Al2 O3/SiO2 composite films with the same nano-alumina （Al2 O3 ） content and the different nano-silica（SiO2 ）content were prepared.The morphology and molecular structure of the composite films were characterized by scanning electron microscopy（SEM）and Fourier transform infrared spectroscopy（FT-IR）respectively.The SEM and FT-IR results indicated that nanoparticles were homogeneous-ly dispersed in the PI matrix,the addition of nanoparticles had no effect on the molecular structure of PI and the thermal imidization of polyamic acid.The mechanical properties,electric breakdown strength and corona-resist-ant performance of the composite films were tested.Test results showed that the breakdown field strength and corona resistant time of the composite film with 0.5% of nano-SiO2 content were 211.15 kV/mm,378 min re-spectively and were superior to the composite films with 0,0.1%,0.3%,0.7% of nano-SiO2 content,and its mechanical properties were more excellent.