Electrical behavior of polypropylene composites melt mixed with carbon-based particles: Effect of the kind of particle and annealing process

Polypropylene (PP) composites with different carbon-based fillers such as graphite (G), thermally reduced graphene oxide (TrGO), and carbon nanotubes (CNT) were prepared by the melt mixed method and the effect of the kind of particle and the annealing process on the electrical behavior was analyzed. Our results show that the electrical conductivity of the resulting composites strongly depends on the filler used. The lowest electrical percolation threshold is obtained when CNT is used as filler whereas when TrGO is used this threshold increases by a factor of two. Noteworthy, composites based on G-microparticles present a percolation process at concentrations one order of magnitude higher than those based on CNT. By annealing the composites at the melt state, the electrical conductivity can be improved several orders of magnitude although depending on the carbon-based particle and its concentration. In particular, composites at concentrations of CNT and G around the percolation threshold are largely affected by the annealing process. The electrical conductivity can also be increased by adding CNT particles to PP/TrGO composites having as consequence a decrease in its percolation threshold. (C) 2014 Elsevier Ltd. All rights reserved.