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The activation and deactivation rate constants in atom transfer radical polymerization (ATRP) were measured using model compounds. The activation rate constants were determined using HPLC or GC under the kinetic isolation condition achieved by trapping the generated radical with 2,2,6,6tetramethylpiperidinyl-1-oxy (TEMPO). The deactivation rate constants were measured by trapping 1-phenylethyl radicals with TEMPO in a competitive reaction. The effects of several parameters in ATRP systems were examined, including alkyl groups, ligands, transferred groups, and solvents. The data obtained were consistent with ATRP kinetics and provided further quantitative insights into understanding the ATRP processes.

The kinetic parameters for the activation and deactivation steps in ATRP for Cu-based catalysts were determined with eight different tridentate nitrogen-based ligands. Additionally, the redox properties of these Cu complexes were measured by cyclic voltammetry. By correlating the kinetic parameters of the activation and deactivation steps with the reduction potential of the Cu(II) complexes, it was found that more reducing Cu catalysts form faster activating Cu(I) and slower deactivating Cu(II) species. The rate of activation depends on the nature of the N-binding site of the ligand. Ligands with alkyl amine or pyridine binding sites form the fastest activating catalysts. The phenyl-substituted ligands form very slowly activating and very rapidly deactivating catalysts. Slower deactivation rates were found for catalysts with a central pyridine unit in the ligand than for catalysts derived from ligands with a central amine unit. In general, the activity of the ligands decreases in the following order:  alkyl amine ≈ pyridine > alkyl imine ≫ aryl imine > aryl amine.

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Immobilization of the catalyst system for atom transfer radical polymerization (ATRP) on various silica and cross-linked polystyrene supports was studied. The catalyst system comprises a copper halide, complexed by various amines. The effect of size of support particles, the amount of immobilized catalyst, and the addition of Cu(II) species as deactivator in the polymerization were investigated. In all cases, polymerization occurred, but generally the reactions were not as well controlled in terms of molecular weight and polydispersities as homogeneous systems. The molecular weights did not match the predicted values, and polydispersities were high (1.5 < M w/M n < 10). However, control was improved by either an increase in catalyst concentration or the addition of deactivator still bound to support to the system. Potential reasons for the reduced control could be the low mobility of the supported catalyst and/or the steric hindrance and incompatibilities between the immobilized catalyst and the polymer chain, thus resulting in a less efficient halogen transfer process compared with homogeneous ATRP.