Enhancement of Percolation Threshold by Controlling the Structure of Composites Based on Nanostructured Carbon Filler

The effect of a multicomponent polymer binder composition on the electrical conductivity of composites filled with carbon black (CB) is reported. Composites based on a mixture of polypropylene and styrene-ethylene-butylene-styrene (SEBS), plasticized with industrial oil, and filled with electrically conductive CB, were prepared using a twin-roller mixer. The presence of various regions in the volume of the binder and the distributions of CB in binder regions was investigated by scanning electron microscopy. The formation of a special conductive network of CB is observed in the investigated composite. The electrical characteristics of the composites were investigated by means of impedance spectroscopy. On the basis of Raman spectroscopy, it was found that CB is predominantly located in the elastomer (in SEBS plasticized with industrial oil), which forms a continuous phase. It has been shown that the spatial distribution of CB (under constant loading of the filler) can change the conductivity of composites by as much as 5 orders of magnitude, and provides a low percolation threshold.