Effect of annealing on the electrical resistivity of conductive polyvinylchloride-copper composites

Abstract
Polyvinylchloride-copper composites at different volume percent of copper are annealed at 50 °C for 10 days. The effect of temperature on the electrical resistivity of the resulting composites is studied between 0 and 40 °C using a four-electrode device. Three clearly distinguished behaviors of the composites are observed after prolonged annealing. They exhibit (a) a positive temperature coefficient of resistance, (b) higher discrepancy in resistivity values for all metal loadings, and (c) an Ohmic current-voltage relationship. We try to explain the positive temperature coefficient of resistance through the reduction of the contact pressure between the metal particles with increase in temperature.