Quantification of Particulate Mixing in Nanocomposites

Quality control has demanded methods to quantify the mixing state of nanoparticles imbedded in polymeric materials. Several quantification methods are reviewed based on the analysis of images from electron microscopy. This includes the quadrat-based skewness, nearest neighbor distance, the k-function and Monte Carlo method. A novel method in which the dispersion and distribution are evaluated respectively through aspects of the equivalent radius deviation and the distance between the gravity centers of particles or clusters is proposed. The efficacy of the method suggested is illustrated by the analysis of transmission electron microscopy (TEM) images of untreated and vinyl-silane treated 12.5 wt% nano-silica/XLPE. It is shown that the combined method provides complete information on the state of the composite, and is the most direct and convenient methodology.