Free‐radical retrograde‐precipitation polymerization process

In this article, we present a newly discovered polymerization process, called the freeradical retrograde‐precipitation polymerization (FRRPP) process, that is shown to have certain desirable features not normally found in free‐radical polymerization processes. Here, free radical polymerization occurs with an unusual but widely applicable polymer precipitation phenomenon. Local heating is observed in the vicinity of the radical sites, which results in the controlled rate of propagation with a decrease in the rate of radical–radical termination reactions. In the case experiments, the existence of hot spots in the reactor fluid is shown to occur. There is also evidence of slowdown of the growth of polymer radicals after initiator decomposition. The polymer radicals, shown to have a relatively narrow molecular weight distribution, continue to grow at a controlled rate long after all the initiator molecules have decomposed. The addition of a second monomer results in the formation of a thermoplastic elastomer triblock copolymer. © 1992 John Wiley & Sons, Inc.