Multistep and semibatch nitroxide-mediated controlled free-radical emulsion polymerization: A significant step toward conceivable industrial processes

Nitroxide-mediated emulsion polymerizations of n-butyl acrylate and styrene were performed with a monofunctional, water-soluble alkoxyamine initiator and a difunctional one. Two different processes were applied, either in two steps or under semibatch conditions. In particular, the polymerization times were strongly reduced, while high conversions and good control over the polymer characteristics were maintained. In all cases, stable latexes were recovered; with the difunctional initiator in particular, they exhibited small particles and narrow particle size distributions. (c) 2006 Wiley Periodicals, Inc.