Tunable temperature-resistivity behaviors of carbon black/polyamide 6 /high-density polyethylene composites with conductive electrospun PA6 fibrous network

Temperature-resistivity behaviors of carbon black/polyamide 6/high-density polyethylene conductive polymer composites containing electrospun polyamide 6 fibrous network were studied systematically. The positive temperature coefficient intensity of the conductive polymer composites increased firstly and then reduced gradually with increasing heating rate, showing a heating rate-dependent positive temperature coefficient intensity. The fascinating phenomenon was ascribed to the microstructure change of conductive network induced by the volume expansion and the thermal residual stress generated in the composites. During the heating-cooling runs at different top testing temperature of 140, 150 and 180℃, the room-temperature resistivity of sample was observed to be 30, 2.3 and 1.6 orders of magnitude higher than the initial value after one heating-cooling run, respectively. The thermal treatment time above the melting temperature of high-density polyethylene and the viscosity variation of the conductive polymer composites were responsible for the increased resistivity. This study provides a guideline for fabricating conductive polymer composites with tuning positive temperature coefficient property.