Etude des facteurs d'extrapolation associés à différents systèmes de polymérisation en émulsion

Abstract : The aim of this thesis is the detennination of the main parameters involved in the scale-up of an emulsion copolymerization process. A detailed review of the literature av ail able on emulsion copolymerization k:inetics and semi-continuous processes used for latex production is presented. Semi-batch polymerizations of 4 industrial recipes which differ in surfactant content and monomer type are carried out and analyzed. The monomer-starved regime is obtained for ail polymerizations. The influence of monomer feed rate and surfactant concentration on final latex properties is established. Nucleation is proven to be the determining step of the process. Seeded polymerizations are investigated as a mean of controlling this step. Thanks to this understanding of the process, possible scale-up parameters are reviewed and their influence is detennined. The influence of mixing on heat and mass transfer at both macroscopic and microscopic scale is reviewed. Transfer phenomena at microscopic scales are shown to be independent of mixing intensity in an agitated tank. Furthermore, well-known parameters such as minimum agitator speed for complete dispersion or upper values of shear rate to avoid coagulation are of importance. The key to a successful scale-up is linked to the competition between mixing and polymerization kinetics. As a consequence, the final number of particles and the particle size will be affected by mixing. A nucleation mechanism is proposed and the influence of the inhomogeneity in the reactor on the nucleation is explained
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Theses
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http://docnum.univ-lorraine.fr/prive/INPL_T_1994_BLEGER_F.pdf
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François Bleger. Etude des facteurs d'extrapolation associés à différents systèmes de polymérisation en émulsion. Autre. Institut National Polytechnique de Lorraine, 1994. Français. ⟨NNT : 1994INPL088N⟩. ⟨tel-01752294⟩

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