改性聚酰亚胺复合材料的电导机理分析

首先,选用半导电的微米级和纳米级改性剂粉料对玻璃布补强聚酰亚胺基复合材料进行改性.共制备了5种试样,其中包括4种使用无碱玻璃布补强的聚酰亚胺试样,分别是未改性、纳米改性、微米改性和微/纳米改性和一种使用微碱玻璃布补强的试样.其次,研究改性剂粒径和玻璃布含碱量对复合材料介电性能及电导率特性的影响.试验结果表明改性剂粒径对复合材料的介电性能影响不显著,但是微米粒径的改性剂能显著提高复合材料的体电导率并赋予复合材料一定的非线性电导率特性,而纳米粒径的改性剂会小量地降低复合材料的电导率.与无碱玻璃布补强的试样相比,采用微碱玻璃布改性和补强的复合材料试样有较高的非线性电导阈值电场. 

Conduction mechanism analysis of modified polyimide composite

Firstly, semi-conductive granules in different diameters from nanometer to micron were used to modify polyimide resin that strengthened by glass fabric. Four kinds of polyimide resin with non-alkalis glass fibers were produced, including the original, micro-filler, nano-filler, and micro/nano-filler modified samples; besides, one kind of polyimide resin with glass fabric that contained small amount of alkalis was prepared as well. The dielectric properties and non-linear conductivity property of all the samples were tested. As a result, it is discovered that the size of filler has little influence on materials' dielectric properties. However, fillers in nanometer decrease a bit of the volume conductivity of the materials, while those in micrometer not only make it increase obviously but also change it into non-linear conductivity. Furthermore, comparing with samples strengthened by non-alkalis glass fabric, the threshold electric field of non-linear conductivity of the polyimide resin strengthened by the glass fabric with small amount of alkalis has a distinct decrease.