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Kinetics of Controlled/Living Radical Polymerization in Emulsified Systems
Author(s) -
Tobita Hidetaka
Publication year - 2008
Publication title -
macromolecular symposia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.257
H-Index - 76
eISSN - 1521-3900
pISSN - 1022-1360
DOI - 10.1002/masy.200850106
Subject(s) - polymerization , chain transfer , living polymerization , radical polymerization , kinetic chain length , chain growth polymerization , polymer chemistry , reversible addition−fragmentation chain transfer polymerization , bulk polymerization , kinetics , living free radical polymerization , chemistry , materials science , monomer , photochemistry , polymer , organic chemistry , physics , quantum mechanics
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, $\bar P_{n,SA}$ . The $\bar P_{n,SA}$ ‐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 p 3 , 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.