Assessment of SET-LRP in DMSO using online monitoring and Rapid GPC

Abstract

Online monitoring with in situ Fourier Transform Near Infra-Red (FT-NIR) spectroscopy and Rapid Gel Permeation Chromatography (Rapid GPC) coupled with light scattering detection are applied to monitor the single-electron transfer living radical polymerisation (SET-LRP) kinetics of methyl acrylate in DMSO. The reaction is catalyzed by copper wire and Me₆TREN ligand at 25 °C initiated by ethyl 2-bromoisobutyrate in the presence and absence of CuBr₂. The data are compared with that obtained from ¹H NMR and conventional GPC. The kinetic results demonstrate that both FT-NIR and Rapid GPC provide comparable conversion data with ¹H NMR and/or offline GPC. Furthermore, significant polymerisation exotherms were observed at the beginning of the reaction in DMSO under certain reaction conditions. In this study, we discuss the possible effect of these exotherms over the polymerization rate by taking into account that a period of slow rate is observed at the initial stage of polymerizations in all cases except where CuBr₂ is added to the reaction mixture.