Multivesiculated polyester particles were synthesized from a double emulsion system comprising water and a solution of unsaturated polyester in styrene. A suspension of solid micro-particles containing multiple water-filled vesicles is obtained after curing (i.e., crosslinking) 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 60Â°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. Â© 2013 Society of Plastics Engineers.
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