Electrical conductivities of carbon powder nanofillers and their latex-based polymer composites

The electrical conductivity of graphene, multi-wall carbon nanotubes, carbon black nanopowders and graphite powder is characterized using paper-like films and by means of powder compression. The large difference in surface area of these materials results in different packing density and number of contact spots, influencing the macroscopic conductivity of the compacts during powder compression. The results are compared with the percolation threshold and final conductivity of polypropylene (PP) composites, using latex technology for the incorporation of the carbon fillers in the polymer. Even though the PP composites produced in this work exhibit percolation thresholds as low as 0.3 wt.%, the final conductivity for all the composites is below 1.5 S/m. Reasons why the high value of ∼103 S/m, which is obtained for graphene- and nanotube-based paper films or graphite compacts, is not reached for the composites are investigated.