C. Hsiao, Hui‐An Han, Gene-Hsiang Lee
Feb 1, 2014
Citations
0
Influential Citations
7
Citations
Journal
European Polymer Journal
Abstract
Abstract Two pyridyl-imine ligands, N , N -dimethyl- N ′-((pyridin-2-yl)methylene)-ethane-1,2-diamine (paenMe 2 ) and N , N -diethyl- N ′-((pyridin-2-yl)methylene)-ethane-1,2-diamine (paenEt 2 ), have been applied to AGET and SARA ATRP of styrene and methyl methacrylate. The polymeric products showed a narrow molecular weight distribution ( M w / M n = 1.16–1.28) and a molecular weight that not only increased linearly with monomer conversion (>70%) but also matched to the theoretical value. The performance of Cu II (paenMe 2 )Br 2 and Cu II (paenEt 2 )Br 2 in AGET ATRP was almost the same and thus the steric effect between these two complexes was not significant. The activation rate constant ( k act ) of Cu I (paenMe 2 )Br with PEBr was measured as 7.96 × 10 −3 M −1 s −1 and the deactivation rate constant ( k deact ) was estimated as 2.8 × 10 5 M −1 s −1 . This kinetic measurement indicated that the improved control efficiency of pyridyl-imine based catalysts in AGET and SARA ATRP should be attributed to the high deactivator/activator (Cu II species/Cu I species) ratio that relatively enhanced the deactivation rate and lowered the radical concentration to minimize the influence of radical termination and other side reactions.