Dispersion kinetics of nano-sized particles for different dispersing machines

For many applications nanoparticles have to be suspended in a fluid phase and dispersed into primary particles or to a definite agglomerate size. Thereby, the prediction of the dispersion kinetic is important among others for comparing the energy efficiency of different dispersion machines. The kinetic models existing today are not able to describe the kinetics over the entire process time correctly. Moreover, a prediction of the dispersion kinetics for new process parameters is not possible. For characterizing the dispersing process and deriving an enhanced model for the dispersion kinetic the stress intensity and the number of stress events in different dispersing machines were investigated. The dispersion kinetic was investigated by dispersing Alumina Alu C (Aeroxide® Alu C, evonik) in distilled water and glycerol using a dissolver, kneader, 3-roller-mill and stirred media mill. Based on these investigations a new model was developed which is able to describe the dispersion process for different dispersing machines and operating parameters with high accuracy. The new model allows the prediction of the minimum reachable end-particle-size in the studied dispersion process and at varying process parameter based on only a few data points. Within the new model the dispersion kinetics depends on two fit parameters, which are only a function of stress intensity and stress frequency alone. Moreover, using the characteristic parameters stress intensity and stress number the dispersion kinetics for new process parameters can be predicted.