Ambient Temperature “Flash” SARA ATRP of Methyl Acrylate in Water/Ionic Liquid/Glycol Mixtures

Abstract

The supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP) of methyl acrylate (MA) in DMSO/ BMIM-PF 6 /glycol mixtures (DMSO, dimethyl sulfoxide; BMIM-PF 6 , 1-butyl-3-methylimidazolium hexafluorophosphate) near room temperature (30 °C), using different SARA agents, is reported. The unusual "hyperpolarity" effect within the solvent mixture allowed very fast and controlled polymerizations (Đ < 1.1) during the entire reaction time. Remarkably, the replacement of DMSO by water in the reaction mixture led to a "flash" polymerization with monomer conversion reaching 92% in only 11 min (degree of polymerization, 222), yet still affording good control over the polymerization.

Aqueous SARA ATRP using inorganic sulfites

“…7,50 Over the years, different systems have been developed to replace these volatile and potentially hazardous organic solvents by “green” solvents 10,51 like supercritical carbon dioxide, 52,53 ionic liquids 49,54-56 or water. 21,26,30,57 Aqueous ATRP usually results in polymers with relatively high dispersity ( Đ ) indicating either poor control or the loss of chain-end functionality.…”

Synthesis of inositol‐based star polymers through low ppm ATRP methods

“…As Ag 0 is a one‐electron heterogeneous reductant, the side reactions that often hinder the efficacy of traditional ARGET ATRP reactions are minimized, and in contrast to the Cu 0 used in SARA ATRP reactions, Ag 0 does not engender a buildup of reactive Cu I through the course of reaction . As evidenced by the low Đ values and high livingness, Ag 0 likely does not act to generate nor terminate radicals in the system contrary to Cu 0 and Fe 0 , thereby eliminating the side reactions observed in other ATRP processes, which have previously led to some loss of chain‐end functionality . As such, Ag 0 next to the applied current approach is an excellent reducing agent for highly controlled ATRP.…”

“…However, a sufficient control was observed, probably because of the slow reducing process with Fe 0 . Previous studies showed that Ag 0 and Cu 0 could reduce Cu II Br 2 /L to Cu I Br/L nearly completely; however, the reduction process proceeded to a much lower extent and was much slower with Fe 0 as a reducing agent, which is caused by the preference of formation of Cu II /L and Fe II /L rather than Cu I /L and Fe III /L species . As Ag 0 is a one‐electron heterogeneous reductant, the side reactions that often hinder the efficacy of traditional ARGET ATRP reactions are minimized, and in contrast to the Cu 0 used in SARA ATRP reactions, Ag 0 does not engender a buildup of reactive Cu I through the course of reaction .…”

Ambient temperature SARAATRP for meth(acrylates), styrene, and vinyl chloride using sulfolane/1-butyl-3-methylimidazolium hexafluorophosphate-based mixtures

“…The solvent polarity plays an important role in the polymerization kinetics. A recent study revealed an unusual increase in polarity, when DMSO/BMIM‐PF 6 /glycol mixtures are used in the SARA ATRP of MA which allows very fast and controlled polymerizations . Furthermore, the presence of water in the sulfolane reactions also contributes to an increase of the rate of polymerization catalyzed by zerovalent metals .…”

“…An unusual synergetic effect of DMSO and 1‐butyl‐3‐methylimidazolium hexafluorophosphate (BMIM‐PF 6 ) for the SARA‐ATRP of MA has been recently reported by our research group, which enabled very fast polymerization rates for a broad range of targeted molecular weights, with a very stringent control over the dispersity during the entire course of the polymerizations . In a further contribution, a synergetic effect is observed in the mixtures of BMIM‐PF 6 and glycols which was explored to access the “flash” polymerization of MA reaching almost full conversion in only 11 min (for target DP = 222).…”