Nonlinear DC voltage-current characteristics of new polymeric composite materials based on semiconductive polyaniline emeraldine base filler

The aim of this study is to develop new polymer-based compounds with nonlinear current-voltage properties and good processability. We have formulated polymeric compounds based on semiconductive polyaniline emeraldine base (PANI-EB). The reference PANI-EB specimen was prepared by powder compacting and solvent casting. Silicone rubber was chosen as the matrix polymer for the composites. We studied the effects of the filler particle loading and of the graphite co-filler on the composite j-E-characteristics. We found that nonlinear j-E-curves can be attained by using either conductive graphite or semiconductive (PANI-EB) fillers alone or combined. Their properties depend strongly on the composite processing and composition. The composites show electrical properties that could readily be utilized in stress grading. In all the sample types and reference samples, we observed alpha-values much higher than the requirement for stress grading applications - the highest being about 25 for bulk PANI-EB with graphite electrodes.