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 polydispersity, and block copolymers. The common drawback of all these processes is the very low polymerization rate which derives from the decreased concentration of propagating radicals. This problem can be overcome in principle by operating in emulsion polymerization, so as to take advantage of radical segregation to decrease terminations without significantly reducing the polymerization rate with respect to the corresponding nonliving processes. In this work, it has been shown that this result can be achieved only using the RAFT (or degenerative transfer) living mechanism and operating in miniemulsion polymerization. Several experiments are presented where, using different 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 literature using different living mechanisms.