Influence of CuBr2 on atom transfer radical polymerization in the presenceof Al(OPri)(3)

Atom transfer radical polymerization of methyl methacrylates(MMA) has been achieved with ethyl-2-bromoisobutyrate [(CH3)(2)CBrCO2C2H5] as an initiator and CuBr, 2,2'-bipyridine(bPy) and aluminum triisopropoxide [Al(OPri)(3)] as an ternary catalyzing system in cyclohexanone at 40 degrees C. MMA can b e polymerized in a living fashion at low temperature with Al(OPri)(3) as a catalytic promoter, The influence of CuBr2 on the ATRP of MMA was discussed in detail in this paper, The radical concentration reduced with the additi on of CuBr2, so bimolecular termination was suppressed. Without the additio n of CuBr2, the produced polymers had high polydispersities (M-w/M-n = 1.94 ), The polymerization of MMA became slower and more controlled with CuBr2 t han without CuBr2, The produced PMMA had low polydispersities (M-w/M-n = 1. 2 similar to 1.5) and controlled molecular weights which were nearly propor tional to monomer conversion, The logarithmic conversion data plotted again st time (ln([M](0)/[M]) vs. t) displayed current first order kinetics in mo nomer.