Carbon Black Dispersion by Electrical Measurements

One of the most important aspects in rubber compounding is achieving good carbon black dispersion in polymeric matrices. The dispersion problem is a length scale phenomenon. The existing experimental tools, which are capable of measuring dispersion, for example Transmission Electron Microscope, Mechanical Scanning Microscope, Optical Microscopy, and Reflectometry, have limitations and the information that they provide is incomplete. The recent advance in instrumentation allows one to include electrical measurements in the arsenal of tools available to quantify dispersion. This paper addresses the DC measurements of rubber compounds including volume resistivity experiments. The approach of measuring current vs. voltage allows one to evaluate the average gap between carbon black aggregates. The results demonstrate that electrical measurements could play an important role in better understanding the filler distribution in bulk elastomeric compound.