Self‐degassing SARA ATRP mediated by Na ₂ S ₂ O ₄ with no external additives

ABSTRACT The supplemental activator and reducing agent (SARA) atom transfer radical polymerization (ATRP) mediated by Na 2 S 2 O 4 in the presence of air, without external deoxygenation or additional oxygen scavengers, is reported for several vinyl monomers: methyl acrylate (MA), n ‐butyl acrylate ( n ‐BA), methyl methacrylate (MMA), 2‐(dimethylamino)ethyl methacrylate (DMAEMA), poly(ethylene glycol) methyl ether acrylate (OEOA), and styrene (Sty). The polymerizations can be conducted in aqueous medium or using organic/water mixtures as solvent, with low concentration of copper, near room temperature. In the absence of any external deoxygenation, several well‐defined homopolymers and block copolymers were obtained ( Ð < 1.3). The evolution of the oxygen concentration during the polymerizations was monitored with an optical oxygen sensor. The consumption of oxygen prior polymerization in ethanol/water mixtures was attributed to the combined presence of Na 2 S 2 O 4 and alkyl halide initiator, which led to a lower initiation efficiency (I eff ). This could be overcome by decreasing the headspace volume of the reaction. The system reported exhibited the potential to be scalable, which is very relevant from an industrial standpoint. © 2019 Wiley Periodicals, Inc. J. Polym. Sci. 2020 , 58 , 145–153