Copper(0)-Mediated Reversible-Deactivation Radical Polymerization: Kinetics Insight and Experimental Study

A comprehensive kinetic model based on the mechanism of supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) was developed to better understand the kinetics of copper(0)-mediated reversible-deactivation radical polymerization [Cu(0)-mediated RDRP]. Simulation results show that diffusional limitation on termination significantly affects on polymerization. A comprehensive description of the variation trend of soluble species and reaction rates during polymerization was illustrated by simulation. The effects on kinetics of four key rate constants (i.e., <i>k</i>_<i>a</i>0, <i>k</i>_<i>disp</i>, <i>k</i>_<i>a</i>1, <i>k</i>_<i>comp</i>) involved in Cu(0)-mediated RDRP were investigated in detail, which contributed to greater insight into the differences between the SET-LRP and SARA ATRP mechanisms. Finally, Cu(0)-mediated RDRPs of methyl methacrylate (MMA) and butyl methacrylate (BMA) were conducted to study the polymerization kinetics at 25 °C. Results of simulations and experiments performed under polymerization conditions show that the Cu(0) surface area-dependent apparent value follows the relationship of <i>k</i>_<i>p</i>1(4)^<i>app</i>/<i>k</i>_<i>p</i>2(5)^<i>app</i> ∝ (<i>S</i>₁₍₄₎/<i>S</i>₂₍₅₎)^1/2 in previously published works. Addition of an initial Cu^IIBr₂ deactivator can significantly improve the controllability of polymerization and reduce the deviation of <i>M</i>_n from theoretical values and larger <i>M</i>_w/<i>M</i>_n at the start of polymerization