SEC-MALLS analysis of cellulose using LiCl/1,3-dimethyl-2-imidazolidinone as an eluent

The lithium chloride/1,3-dimethyl-2-imidazolidinone (LiCl/DMI) solvent system for cellulose was adopted as a mobile phase of size-exclusion chromatographic ( SEC) analysis of cellulose, and the applicability of this system was examined using multi-angle laser light scattering and C-13-NMR analysis. The results indicate that 8% (w/v) LiCl/DMI is a true solvent for cellulose, and that cellulose molecules dissolving in 1% (w/v) LiCl/DMI are separated orderly depending on their molecular mass (MM) or root-mean-square (RMS) radius by the SEC system. Practically, no aggregates were detected in the dilute cellulose/LiCl/DMI solutions. Furthermore, high stability of cellulose/LiCl/DMI solutions has been demonstrated; only a few percent of decline in average MM was observed even after storage for 6 months at room temperature. Relationships between RMS radius and MM for hardwood bleached kraft pulp in 1% LiCl/DMI was estimated as the following equation: R-g proportional to M-0.59, corresponding to a Mark-Houwink-Sakurada exponent of 0.77.