Kinetics of Controlled/Living Radical Polymerization in Emulsified Systems

Summary : For the controlled/living radical polymerization (CLRP) in which the active period during the chain formation is extremely small, ϕ A < 1, such as the cases of usual SFRP and ATRP, the polymerization rate can be made larger by increasing the average number of monomeric units added during a single active period, Pn,SA . The Pn,SA ‐value is inversely proportional to the trapping agent concentration [ X ], and the polymerization rate is controlled by [ X ]. For small particles, even with a single trapping agent, [ X ] in the particle could be larger than that in corresponding bulk polymerization, and the polymerization rate decreases with D , where D p is the particle diameter. On the other hand, for CLRPs whose ϕ A ‐value is not very much smaller than unity, say ϕ A >0.01, such as some of RAFT polymerization systems, the polymerization rate can be made larger by increasing the kinetic chain length for a given initiation frequency. For such reaction systems, the polymerization rate can be enhanced significantly by employing the emulsified polymerization systems.