Miniemulsion living free radical polymerization by RAFT

Various living mechanisms have been used in bulk polymerization to produce via free radical polymerization both controlled polymers, i.e., with low po lydispersity, and block copolymers. The common drawback of all these proces ses is the very low polymerization rate which derives from the decreased co ncentration of propagating radicals. This problem can be overcome in princi ple by operating in emulsion polymerization, so as to take advantage of rad ical segregation to decrease terminations without significantly reducing th e polymerization rate with respect to the corresponding nonliving processes . In this work, it has been shown that this result can be achieved only usi ng the RAFT (or degenerative transfer) living mechanism and operating in mi niemulsion polymerization. Several experiments are presented where, using d ifferent monomers, living conditions are achieved without significant loss in productivity. The obtained results are supported by modeling arguments, which also rationalize previous experimental results reported in the litera ture using different living mechanisms.