Conductivity of Polymer Composites with Nanocarbon Filler

The results of resistivity investigations of polymer composites based on thermoexfoliated graphite and reinforced by carbon fibers with different polymers are presented. For preparation of composites, three polymers (polyvinyl acetate, phenol–formaldehyde resin, and silicon-organic binder) have been chosen. The concentration of nanocarbon filler ranged from 0.04 to 1 mass parts. The electrical resistance of obtained polymer-nanocarbon specimens perpendicular and parallel to the compression axis at room temperature and perpendicular to the compression axis in the temperature interval from 77 to 293 K has been measured by a four-probe compensation method. It is shown that resistivity concentration dependence has a percolation character both for specimens based on thermoexfoliated graphite and on the thermoexfoliated graphite and reinforced with carbon fiber. The type of polymer does not significantly affect the character of the concentration dependence of resistivity perpendicular to the compression axis. Differences in concentration dependences of anisotropy parameter for polymer composites with different polymers are revealed. It was found that the main factor that determines the value of electrical resistivity in polymer composites with carbon filler is the content of carbon filler in these composites.