Facile characterization of molecular weight distribution of cellulose by gel permeation chromatography using a dimethyl sulfoxide solution containing 1% EmimOAc

Recently, various methods for cellulose dissolution without derivatization pretreatment have garnered attention for measuring the molecular weight of cellulose using gel permeation chromatography (GPC). However, conventional methods require complex pretreatment procedures or use substantial quantities of ionic liquids, which are expensive and exhibit high viscosities. Herein, we report a GPC method for the successful dissolution of cellulose in dimethyl sulfoxide (DMSO) containing 1 wt% 1-ethyl-3-methylimidazolium acetate (EmimOAc). The GPC method is simple, does not require special pretreatment steps, and dissolves cellulose at room temperature. Moreover, as the concentration of the ionic liquid was as low as 1 wt%, the method was robust at low pressures in the GPC system and had low operating costs for the ionic liquid. We demonstrate the applicability of this GPC method to various types of cellulose, including cotton, pulp, and rayon. The GPC profiles of EmimOAc/DMSO were comparable to those of the conventional GPC systems using lithium chloride/dimethyl acetamide in terms of the peak top molecular weight (and shoulder peak in the low-molecular-weight region). Therefore, this GPC method can contribute to the high-throughput evaluation of the molecular weights of native and regenerated cellulose.