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.