Large volume and oxygen tolerant photoinduced aqueous atom transfer radical polymerization

We scaled up the aqueous photoinduced ICAR (PICAR) ATRP of acrylamide (AAm), with a scale-up factor of 400, from V-i = 5.0 mL to V-f = 2.0 L. Relatively large mixtures can be polymerized by 395 nm light, up to very high conversions while maintaining a narrow molecular weight distributions, in the presence of sodium pyruvate, which acts as both reactive oxygen species scavenger and exciter for [(CuL)-L-I](+) (re)generation. The best reactions conditions were determined by analyzing the buffer strength, halide source nature and concentration, light wavelength, catalyst concentration, sodium pyruvate concentration, and initiator type. PICAR ATRP was suc-cessfully applied as well to other hydrophilic monomers besides AAm. The reaction progress could be monitored online via electrochemical methods. The best small-scale reaction was then scaled up with AAm to 40, 250, 500, 1000 and 2000 mL. The estimated crude cost of polyacrylamide (PAAm) and the reagent cost of the reaction mixture revealed that PICAR ATRP is feasible at large scale.

Automated summary

In this study, the aqueous photoinduced ICAR ATRP of acrylamide was successfully scaled up from small-scale to large-scale. By optimizing the reaction conditions, this method can efficiently and feasibly produce a large quantity of polyacrylamide.