Modeling of MWD in emulsion polymerization: Partial distinction approach

A mathematical model for the calculation of the MWD in emulsion polymers is presented. The model is based on an intermediate level of description of the system, and hence is computationally more efficient than the existing detailed models, while its predictions are as accurate as those of the detailed models. The importance of the compartmentalization was assessed to determine the conditions in which there is a need to account for the compartmentalization. It was found that under many practical conditions, the predictions of models even simpler than that developed in this work are accurate enough. Only for highly compartmentalized systems, under conditions in which 0.5<(n) over tilde<0.7, with a strict control of the operation variables and very good GPC analysis, the differences between the models would be greater than the experimental variability. The feasibility of the on-line estimation of the MWD in seeded systems was studied. It was found that an accurate, robust and quick prediction of the MWD in seeded systems using available on-line measurements (calorimetry, gas chromatography) seems to be possible.