Photo-induced copper-mediated polymerization of methyl acrylate in continuous flow reactors

Abstract

Copper-mediated radical polymerization of acrylates was carried out in micro- and milliscale UV continuous flow reactors in the absence of conventional photoinitiators.

Photo-induced copper-mediated radical polymerization of methyl acrylate (MA) is carried out in DMSO at 15 °C in a tubular photo-flow reactor as well as in a glass-chip based microreactor. Polymerization reactions proceed rapidly to approximately 90% monomer conversion within 20 minutes of reactor residence time. Control of reactions is high as evidenced by ideal polymerization kinetics, low dispersities of the obtained polymers (in the range of 1.1) and linear evolution of number average molecular weights during polymerization reactions. Poly(MA) with average molecular weights between a few hundred and ∼5000 g mol ⁻¹ was obtained under retention of pristine end group fidelity. Besides homopolymers, block copolymers can also be successfully synthesized and poly(methyl acrylate)- b-poly(butyl acrylate) block copolymers with a similar low dispersity are obtained. Reactions proceed under homogeneous reaction conditions. This feature allows the reaction to be carried out in milli- and also in microflow devices. In both cases, equally good control is achieved with only minimal adaptation of the reaction protocol, underpinning the simplicity and fast adaptability of the protocol to different flow reactors.