Nickel-mediated living radical polymerization of styrene in conjunction with tetraethylthiuram disulfide

The radical polymerization of styrene initiated with tetraethylthiuram disulfide (TD)/nickel (II) chloride (NiCl2)/triphenylphosphine (PPh3) was of living nature via a one-electron redox reaction between nickel(II) and (III) species. The mechanism belonged to reverse atom transfer radical polymerization (reverse ATRP). The living essence was affected by the molar concentration of the initiator and catalyst. With the feed ratio of [MMA]0/[TD]0 equal to 1000/1, the kinetics was of first order on the monomer. The values of number-average molecular weights measured by gel permeation chromatography (GPC) of resulting polymers were in close agreement with those calculated by the assumption that one living radical generated one polymer chain, and molecular weight distributions were as low as 1.34. α-S2CNEt2 and ω-Cl were demonstrated to end-cap the polymer chain. PSt-b-PMMA could be produced by the polymerization of MMA initiated with the resulting PSt-Cl/CuCl/bpy through a normal ATRP procedure.