Homogeneous atom transfer radical polymerization of styrene initiated by 1-chloro-l-phenylethane copper(I) chloride bipyridine in the presence of dimethylformamide

Homogeneous atom transfer radical polymerization of styrene initiated with 1-chloro-1-phenylethane/CuCl/2,2'-bipyridine at 130 degrees C is easily achieved in the presence of a limited amount of dimethylformamide (similar to 10% v/v). The kinetics are in agreement with the accepted ATRP mechanism. For initial monomer-to-initiator ratios up to 400, the molar masses increase linearly with conversion and perfectly fit the calculated value for a controlled polymerization, and the results are still satisfactory up to a ratio of 650. For higher values of this ratio, the polymerization is no longer controlled, and this is attributed to thermal initiation, irreversible termination, and/or transfer.