Advances in Filler Dispersion Measurement

It is well documented that filler dispersion significantly influences rubber performance. However, there is no single experimental method to measure dispersion accurately and efficiently. In this paper, the authors will undertake to close the knowledge gap in understanding dispersion by presenting new experimental techniques and reviewing several existing ones that measure dispersion at different length scales. Some methods like electrical resistivity, are able to probe only the conductive carbon black network, while others take into consideration all compounding ingredients including mineral fillers and other chemicals. Two techniques that will be discussed in more detail are surface profilometry, based on the non-contact optical interferometry principle, and the second based on high resolution FE-SEM imaging. Data obtained by these different techniques from multiple rubber compounds (with varying dispersion levels) will be presented and the interpretation of this data will be discussed.