Changing the percolation threshold of a carbon black/polymer composite by a coupling treatment of the black

It is well-known that a polymer composite filled with a conductive filler such as carbon black (CB) becomes electrically conductive once the volume fraction of CB exceeds a certain critical value the so called percolation threshold. Moreover, the percolation threshold can be lowered by blending with immiscible polymers, optimizing the process conditions, and controlling the size distribution and porosity of the CB. In fact, a low concentration of CB particles is desired from a practical point of view in terms of both the mechanical properties and workability of the composites. However, very few efforts have been made to reduce the critical CB content by surface treatment of the CB. In this paper, we introduce a way to decrease the critical loading level of CB via a general coupling treatment of the CB to a value considerably lower than the percolation threshold reported elsewhere.