RETRACTED: Temperature Dependence of Resistivity of Carbon Black Filled Polymer Matrix Composites Below and Above Percolation Threshold (Retracted Article)

The effect of the temperature on the resistivity of carbon black filled polymer matrix composites below and above percolation threshold (P-t) was studied based on the electrical conduction mechanism. Temperature coefficient of resistance of the composites below percolation threshold changed from negative to positive at 0.195<P-t<0.210, and the trend decreased with increasing of P-t. The temperature dependence of the resistivity of the composites below P-t can be explained with a tunneling conduction model by incorporating the effect of the thermal expansion of the composites into a tunneling gap. The temperature coefficient of resistance of the composites above P-t has a positive value and its absolute value increased with increasing volume fraction of carbon black. By assuming that the electrical conduction through percolating paths is a thermally activated process and by incorporating the effect of thermal expansion into the volume fraction of the carbon black, the temperature dependence of the resistivity above P-t has been well explained without violating the universal law of conductivity; the apparent activation energy is estimated to be 0.14 eV.