Macromol. Chem. Phys. 5/2010

Simulation of reversible chain transfer catalyzed polymerization (RTCP): effect of different iodide based catalysts

“…Figure 5 illustrates the monomer conversion against polymerization time. In agreement with Goto et al [19], RTCP systems represent lower polymerization rates (R p ) attributed to crosstermination reactions. Due to higher k da /k a ratio amounts, lower monomer conversions against reaction time are resulted in polymerization systems comprising faster catalyst depletion.…”

“…Goto et al [19] investigated that in the same catalyst concentration, activation rate constant (k a ) increases in the order of PI 3 (phosphorus catalyst) <p-tolyl germanium triiodide (tolyl-GeI 3 ) (germanium catalyst) <N-iodosuccinimide (NIS) (nitrogen catalyst) <SnI 4 (tin catalyst) <GeI 4 (germanium catalyst). They also mentioned that k a is proportional to the deactivation rate constant (k da ).…”

“…In the former called pre-equilibrium reversible chain transfer (reactions i and j), iodine exchange occurs reversibly between PhE-I and A* (radical obtained from AI) and in the latter, reversible chain transfer, a radical transfer takes place by iodine transmission among the catalyst and macroradicals (reactions k and l). Finally, in reaction m the activator radical reacts with propagating macroradicals and causes a cross termination resulting in depletion of the catalyst [1,[14][15][16][17][18][19]. The kinetic parameters of each reaction are demonstrated in Table 1.…”

“…In the presence of AI catalyst (GeI 3 -I, etc.) another reversible reaction mechanism called the reversible chain transfer (RT) coexists which results in a low polydispersity by activating Polymer-I frequently [1,[14][15][16][17][18][19][20]. RT equilibriums are sensitive to the catalyst activity and concentration, therefore various polymer architectures could be attained by employing different catalysts at several concentrations [19].…”

H‐Phosphonic Acid Derivatives as Catalysts for Reversible Chain Transfer Catalyzed Polymerization (RTCP) at Ambient and High Pressure

“…[20] Thus, a higher control of the molar masses should be obtained. [21] The utilized PADs shown in Figure 1 were employed as precursors for the in situ production of the activator radical (1c)].…”