Up in the air: oxygen tolerance in controlled/living radical polymerisation

Abstract

The requirement for deoxygenation in controlled/living radical polymerisation (CLRP) places significant limitations on its widespread implementation by necessitating the use of large reaction volumes, sealed reaction vessels as well as requiring access to specialised equipment such as a glove box and/or inert gas source. As a result, in recent years there has been intense interest in developing strategies for overcoming the effects of oxygen inhibition in CLRP and therefore remove the necessity for deoxygenation. In this review, we highlight several strategies for achieving oxygen tolerant CLRP including: "polymerising through" oxygen, enzyme mediated deoxygenation and the continuous regeneration of a redox-active catalyst. In order to provide further clarity to the field, we also establish some basic parameters for evaluating the degree of "oxygen tolerance" that can be achieved using a given oxygen scrubbing strategy. Finally, we propose some applications that could most benefit from the implementation of oxygen tolerant CLRP and provide a perspective on the future direction of this field.

An Oxygen Paradox: Catalytic Use of Oxygen in Radical Photopolymerization

“…Structurally,Z nOETPP possesses eight ethyl substituents in the b-carbon positions of the pyrroles as well as the four phenyl substituents in the meso positions.T ominimize the steric interactions,the pyrroles and its substituents tilt above and below the central plane of the porphyrin in an alternating fashion while the phenyls rotate into the macrocycle plane (Supporting Information, Video 1). [6] Kinetic investigation of N,N-dimethylacrylamide (DMA) under aerobic conditions revealed that the polymerization progressed in al inear fashion after as hort (ca. [16] With an expectation that ZnOETPP would behave similarly to the previously studied ZnTPP, [16] we examined its oxygen tolerance capabilities as as tarting point by polymerizing in the presence (Supporting Information, Table S1, entry 1) and absence (Supporting Information Table S1, entry 2) of air.…”

“…To our amazement, only the nondeoxygenated reaction achieved polymerization with an excellent agreement between the theoretical and experimental (GPC) molecular weights (M n ), and an arrow molecular weight distribution (MWD, M w /M n = 1.09). [17] To test this hypothesis,w ea dded triethylamine (TEA) at 1equivalence to the trithiocarbonate for the polymerization of MA under both aerobic and anaerobic conditions (Supporting Information, Table S1, entries 5,6). [6] Kinetic investigation of N,N-dimethylacrylamide (DMA) under aerobic conditions revealed that the polymerization progressed in al inear fashion after as hort (ca.…”

Copper‐Mediated Polymerization without External Deoxygenation or Oxygen Scavengers

“…13 For instance, Chapman et al. elegantly used enzymes, such as glucose oxidase (GOx), to effectively deoxygenate traditional RAFT polymerizations 14, 15.…”

An oxygen‐tolerant photo‐induced metal‐free reversible addition‐fragmentation chain transfer polymerization

“…However, almost no investigations have involved the use of oxygen in redox‐initiated radical polymerization reactions. In recent years and in response to demands from industry, a growing number of oxygen‐tolerant polymerization techniques have been developed ,. Most of these reactions were conducted at room temperature via redox initiation.…”