ICAR ATRP for Estimation of Intrinsic Macro-Activation/Deactivation Arrhenius Parameters under Polymerization Conditions

The potential of Initiators for Continuous Activator Regeneration Atom Transfer Radical Polymerization (ICAR ATRP) to determine reliable Arrhenius parameters for ATRP activation/deactivation of macrospecies is illustrated using styrene as monomer and CuBr2/TPMA (TPMA: tris(2-pyridylmethyl)amine) as deactivator. Regression is based on an extensive set of experimental data limited to conversions below 0.50 to avoid the interference of diffusional limitations on the activation/deactivation process and recorded at temperatures below 90 degrees C to avoid the influence of thermal self-initiation. Diffusional limitations on termination are accounted for based on literature data. The activation energy for the activation and deactivation reaction involving macrospecies are respectively 29 and 1.7 kJ mol(-1). The corresponding pre-exponentional factors are 6.9 x 10(5) and 1.8 x 10(7) L mol(-1) s(-1). At 70 degrees C, the corresponding rate coefficients amount to 2.2 x 10 and 9.9 x 10(6) L mol(-1) s(-1) confirming the relatively high activity of CuBr/TPMA as ATRP catalyst.