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Dispersion of liquid-liquid systems is often applied in industrial processes such as extraction, suspension, and emulsion polymerization. The influence of emulsification of the monomer in the aqueous phase on the course and outcome of the batch emulsion polymerization of styrene has been studied. A visual criterion was applied for determining the lowest impeller speed for sufficient emulsification (N*). It appeared that in polymerization experiments under the same conditions, N* was the critical value above which no further increase in polymerization rate was observed. Using a turbine impeller instead of a pitched blade impeller as well as using a larger impeller diameter provides better emulsification at constant power input. The results indicate that scale-up with constant impeller tip speed is most appropriate in case of a turbine impeller.

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Thermodynamic phase equilibrium data relevant to the copolymerization of carbon dioxide (CO 2 ) and cyclohexene oxide (CHO) are reported in this paper. In this system, the need for additional solvents can be prevented by using an excess of the comonomer CO 2 . Therefore, the solubility of poly(cylcohexene carbonate) (PCHC) in CO 2 and the effects of molecular weight and CHO concentration have been experimentally determined using a high-pressure view cell. Since extremely high pressures are required to dissolve PCHC in CO 2 , only low-molecular-weight polymer is soluble within the experimental pressure range. Addition of CHO results in a significant decrease of the cloud-point pressures and a change of the slope of the cloud-point curve in PT-space. The perturbed-chain SAFT equation of state has been successfully used for the correlation and the prediction of the phase behavior in this range. At high temperatures the PC-SAFT model allows for a quantitative description of the phase behavior, whereas at lower temperatures PC-SAFT tends to overestimate the cloud-point pressures.