A review of the use and limitations of Population Balance Equations (PBE) in the modeling of emulsion polymerisation (EP), and in particular of the particle size distribution of the dispersed system is presented. After looking at the construction of the general form of PBEs for EP, a discussion of the different approaches used to model polymerization kinetics is presented. Following this, specific applications are presented in terms of developing a two-dimensional PBE for the modeling of more complex situations (for example the particle size distribution, PSD, and the composition of polymerizing particles). This review demonstrates that while the PBE approach to modeling EP is potentially very useful, certain problems remain to be solved, notably: the need to make simplifying assumptions about the distribution of free radicals in the particles in order to limit the computation complexity of the models; and the reliance of full models on approximate coagulation models. The review finishes by considering the different numerical techniques used to solve PBEs.

The adsorption of sodium dodecyl sulfate (SDS) and sodium dodecyl benzenesulfonate (SDBS) on poly(vinyl chloride) (PVC) latex particles was investigated. Conductometric titrations were performed to determine the area per surfactant molecule at various temperatures (20-50ºC) and the adsorption isotherms of both emulsifiers were determined at 20ºC from surface tension titration curves. The adsorption data show some deviation with respect to the Langmuir isotherm due to their slight S-shape. The data can nevertheless be fitted very well with a limiting form of the general adsorption equation proposed by Zhu and Gu (Adv. Colloid Interface Sci. 37 (1991) 1).

The fixed pivot technique of Kumar and Ramkrishna (Chem. Eng. Sci., 1996, 51 (8), 1311-1332, originally derived for one-dimensional systems, is extended to simulate twocomponent aggregation processes. By following this approach, it is possible to design a numerical method that guarantees internal consistency with regard to certain moments of the distribution, while using arbitrary Cartesian grids. Focus is put on achieving internal consistency with respect to the number of particles and the mass of each component, although other moments may be considered if desired. The potentialities and limitations of the technique are evaluated by comparing the numerical solutions against available analytical solutions. This comparison reveals that the proposed method is rather accurate, except in the front region, which shows some smearing. The accuracy, internal consistency, and computational efficiency of this numerical method should make it a valuable tool for simulating two-component aggregation.