A Simple Methodology for the Modeling of Carbon Black Aggregate Structure

A procedure for modeling some morphological characteristics of carbon black aggregates is presented. The method uses a standard reaction limited aggregation algorithm to predict the location of the centers of primary particles within an aggregate. The shape of the aggregate is determined by drawing simple linear links between extreme points of primary particles centered on these loci. Analysis of the particle distribution function computed from the simulated structure leads to definitions of the interior and periphery of the aggregate structure. Direct comparisons between simulated aggregates and two commercial carbon blacks are presented to illustrate the usefulness of the approach. The perimeter fractal dimension of simulated aggregates can be made to match the perimeter fractal dimension of the commercial carbon black aggregates through proper choice of the sticking probability in the simulation algorithm. With this proper choice of sticking probability, the relative amounts of voids in the periphery and interior of the simulated aggregate correspond to relative amounts of filled and unfilled voids in actual aggregates that have been soaked for extended periods of time with processing fluids.