70e Aggregation with Collision-Induced Breakage: Solutions and Comparison with Linear Breakage

R. Dennis Vigil, Isaac Vermeersch, and Rodney O. Fox. Department of Chemical & Biological Engineering, Iowa State University, 2114 Sweeney Hall, Ames, IA 50011-2230

Mean-field population balance equations are used to describe the evolution of particle size distributions in a wide variety of systems undergoing simultaneous aggregation and breakage. We develop a population balance that includes aggregation combined with collision-induced particle breakage for arbitrary fragment distribution functions, provided that this distribution function depends only on the total mass of the particles undergoing a collision. We then develop a specific distribution function for arbitrary two-body collisions by postulating that each collision produces a transition-state aggregate having the morphology of a linear polymer. The behavior of the resulting equation is then analyzed for the case in which the collision kernel is a constant, and partial analytical solutions are derived and compared to corresponding Monte-Carlo simulation results. The computer simulations are then used to validate a proposed scaling law for the steady-state particle size distribution. Lastly, the behavior of the aggregation with collision-induced breakage population balance equation is compared and contrasted with the behavior of an analogous aggregation with linear breakage population balance equation, and the relevance of each model for predicting cluster size distributions of polymer microspheres in solution is assessed in light of experimental data.