Lifetimes of polystyrene chains in atom transfer radical polymerization

Polystyrene was polymerized via atom transfer radical polymerization (ATRP) using CuBr/4,4′-di(5-nonyl)-2,2′-bipyridine (dNbpy) as the catalytic system and 1-phenylethyl bromide as the initiator. At the very beginning of the polymerization, a large number of radicals were generated and terminated very quickly, resulting in the loss of approximately 5% of chains and the formation of 5% of Cu(II) species from the initial Cu(I) species. This buildup of Cu(II) species led to the decrease of radical concentration, very fast deactivation, and significant reduction of termination.