Atom Transfer Radical Polymerization of Styrene in the Presence of Oxygen

ABSTRACT

Atom transfer radical polymerization (ATRP) has historically required an oxygen‐free environment to prevent oxidation of both the polymeric radical and the active copper catalyst, limiting its deployment in industrial‐scale processes. In this study, ATRP of styrene was successfully carried out in the presence of oxygen by using triethylborane (TEB) complexed with an aryl amine to form air‐stable complexes, which served as an essential component of the reaction mixture. Polymerizations conducted in DMSO at 80°C reached high yields within 10 h while maintaining relatively low dispersity (Ð ≈ 1.11), although the molecular weights exceeded theoretical values. When the reaction was allowed to proceed for 24 h, dispersity increased and a low‐molecular‐weight shoulder became apparent on GPC. When the complexed triethylborane was omitted, no polymerization was observed to occur when carried out in the presence of oxygen. The brominated polystyrene precursor formed with oxygen present was successfully chain extended, indicating chain end fidelity and consistent with the ATRP mechanism.