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Multivesiculated polyester particles (MVPs) are obtained by reticulation of a double emulsion system formed by a polyester/styrene solution dispersed in an aqueous colloidal solution. During its synthesis, the acid/base reaction between polyester carboxylic end groups and an added amine plays an important role in stabilizing the two emulsion systems (water‐in‐oil and oil‐in‐water). This work studies the influence of diethylenetriamine, aminoethylethanolamine, diethanolamine, and triethanolamine on MVPs' average particle size, vesiculation morphology, dry film opacity, and yellowing. The particular aspects observed for each amine are discussed, allowing identification of the relevant mechanisms taking place in the formation of MVPs. POLYM. ENG. SCI., 53:2261–2269, 2013. © 2012 Society of Plastics Engineers

Resiquímica -Resinas Químicas S.A., Rua Francisco Lyon de Castro, 28, 2725-397 Mem-Martins, Portugal Multivesiculated polyester particles were synthesized from a double emulsion system comprising water and a solution of unsaturated polyester in styrene. A suspension of solid microparticles containing multiple water-filled vesicles is obtained after curing (i.e., cross-linking) the dispersed organic phase. These have several applications, like opacifying agents in paint formulations. The effects of curing time and temperature on relevant properties of the final product (particle size distribution, dry film opacity, dispersion viscosity, and stability) were investigated. Results showed that more than 1 h was necessary when curing at room temperature, in order to avoid coalescence and loss of opacity upon drying. On the other hand, well-individualized particles were obtained within a few minutes when curing above 60 o C, and the internal alveolar structure was preserved after drying. Furthermore, high curing temperatures enhanced not only the final dry film opacity, but also originated less viscous and more stable particle dispersions. POLYM. ENG. SCI.,

Aqueous multiphase systems (AMPS) were formed by mixtures of three or more incompatible water soluble macromolecules. Droplets formed by different phases in the water-in-water emulsions were found to associate and their morphology was studied using confocal laser scanning microscopy.By analysing the angles between different associated phases it was possible to determine the relative interfacial tensions between phases with respect to each other. In this manner the relative interfacial tension of 15 different pairs of polymers solutions was determined. The effect of the total polymer concentration on the relative interfacial tensions was found to be small as long as mixing of the polymers in the phases was small. The effect of adding protein microgels was studied for systems where they adsorb at the interface between the phases. It is shown that protein microgels can in some cases stabilize associated droplets in suspension.

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