Modelling prediction of the microcapsule size of polyelectrolyte complexes produced by atomization

In order to have a better understanding of the atomization process for microencapsulation applications the disintegration of polymer liquid jets (sodium alginate) injected into high-velocity gas streams was studied and a mathematical model to predict the microparticle size has been developed.Air-blast atomization of viscous non-Newtonian fluid (alginate solution) was carried out in order to produce microbeads (1–50 μm) based on polyelectrolyte complexes with particle size control and a particle size distribution with a relative span factor, (D0.9 − D0.1)/D0.5, less than 1.4. The accuracy of the wave-mechanisms-based models in predicting droplet size after breakup of alginate solution has been demonstrated. The atomized microparticle size were expressed in terms of three dimensionless groups, the liquid/air mass ratio, the Weber number and the Ohnesorge number in simple forms whose exponents and coefficients were determined by least-squares fit to the experimental data. With these data two semi-empirical models have been proposed to predict the particle size obtained from the microencapsulation. Both models allow the prediction of particle size of the microcapsules obtained by atomization processes.