Kinetic study of the homogeneous atom transfer radical polymerization of methyl methacrylate

The homogeneous controlled/''living'' radical polymerization of methyl methacrylate (MMA) using the atom transfer radical polymerization (ATRP) with CuCl/4,4'-di(5-nonyl)-2,2'-bipyridine catalytic system and diphenyl ether as the solvent generated well-defined polymers with polydispersities M-w/M-n less than or equal to 1.2. The evolution of the molecular weights of the polymers follows the ratio of the mass of the consumed monomer to the initial initiator concentration. The rate of polymerization follows first-order kinetics with respect to the decrease of monomer concentration. The polymerization rate reaches a maximum when the ratio of ligand-to-(CuCl)-Cl-I is one-to-one. ATRP of MMA shows first-order kinetics with respect to both (CuCl)-Cl-I and the initiator, alkyl or sulfonyl chloride. The rate of polymerization did not obey simple negative first-order kinetics with respect to the concentration of (CuCl)-Cl-II, partially due to a persistent radical effect, which resulted in the increase of [(CuCl)-Cl-II] in the initial stage of polymerization. Thermodynamic data and activation parameters for the solution ATRP of MMA are reported.