6533b85efe1ef96bd12bfd2f

RESEARCH PRODUCT

Kinetic Analysis of “Living” Polymerization Systems Exhibiting Slow Equilibria. 3. “Associative” Mechanism of Group Transfer Polymerization and Ion Pair Generation in Cationic Polymerization

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The averages of the molecular weight distribution are derived for a “living” polymerization process which proceeds via active and “dormant” species and where the active species are formed by addition of a catalyst to a “dormant” species. Such a mechanism is applicable to group transfer and “living” cationic polymerizations (assuming that ion pairs are formed exclusively in the latter case). Both equilibrium and nonequilibrium initial conditions are used for the calculation. The results are very similar to those obtained for degenerative transfer (i.e., direct exchange of activity between active and “dormant” species). The dominating parameter is β = k2/(kpI0), where k2 and kp are the rate constants of reversible deactivation and propagation, respectively, and I0 is the initial initiator concentration (for degenerative transfer this parameter was given as β = kex/kp, independent of initiator concentration). As an example, for β > 1 the polydispersity index decreases with monomer conversion (after a marked ...