Emulsification in batch emulsion polymerization

Abstract

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.

Diffusion‐Controlled Particle Growth and its Effects on Nucleation in Stirred Emulsion Polymerisation Reactors

“…[3] At a low stirring speed, the rate of polymerisation is diffusion controlled. [2][3][4][5] This has been associated with a formation of a larger number of particles. [6][7][8] The effects of impeller speed and/or type on the rate of copolymerisation, molecular weights, [4,9] and particle size distribution [10] have been also reported.…”

Potentials and Limitations of Automated Parallel Emulsion Polymerization

“…Emulsification can be determined by means of visual observation of the lowest impeller speed required for sufficient emulsification N vis * , defined by Skelland and Seksaria. [29] Kemmere et al [30] empirically determined this stirring speed for Sty and VAc batch emulsion polymerizations with conventional pitched blade impellers. To the best of our knowledge, however, nothing is published on emulsification by means of vortex stirring.…”

Emulsification in batch-emulsion polymerization of styrene and vinyl acetate: A reaction calorimetric study

“…16 Both methods have shown limitations for the investigation of emulsification. 1 As the measurement of a critical droplet size only results in a certain arbitrarily defined number, we have chosen to use the visual observation of sufficient emulsification based on N * vis throughout.…”

“…1 Emulsification is the process of making an emulsion from a system consisting of two more or less immiscible liquids. 2 To facilitate emulsification, a surfactant is added in many cases.…”

“…The impact of emulsification during emulsion polymerization of styrene was already reported in a previous article. 1 The influence of dispersion of the monomer in the continuous aqueous phase on the course and outcome of the batch-emulsion polymerization process has been studied. For this purpose a criterion developed by visualization experiments has been applied for determining an impeller speed (N* vis ) just sufficient to completely disperse the monomer phase into the aqueous phase.…”