Time temperature superposition of the dissolution of cellulose fibres by the ionic liquid 1-ethyl-3-methylimidazolium acetate with cosolvent dimethyl sulfoxide

Abstract

The dissolution of cellulosic flax fibres in the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) with cosolvent dimethyl sulfoxide (DMSO) has been studied. The fibres were submerged in the ionic liquid/DMSO mixtures at different temperatures for a range of dissolution times, then coagulated in water. After drying, cross sections of the fibres were analysed using an optical microscope, which was used to track the fraction of coagulated fibre. The temperature dependence of this coagulated fraction is found to follow an Arrhenius equation with a single activation energy of 100±10 kJ/mol. This value is, remarkably, independent of the weight fraction of DMSO used. This work quantifies the composition for the peak dissolution rate, which occurs at an equal weight fraction of DMSO and [C2mim][OAc]. Finally, this study reveals an equivalence between time, temperature and DMSO weight fraction in the dissolution of flax fibres.