Conformation and d n/d c determination of cellulose in N,N-dimethylacetamide containing lithium chloride

Abstract

In order to characterise cellulose dissolved in lithium chloride/ N,N-dimethylacetamide (LiCl/DMAc) using size-exclusion chromatography with online multiangle laser light scattering and differential refractive index detection, a number of parameters were determined. One of them in particular, the specific refractive index increment (d n/d c) of cellulose in 0.5% LiCl/DMAc, is required in order to calculate the molar mass from the light scattering signal. Pure cellulose paper was used as sample source. The precision and reproducibility of the SEC/MALS/DRI method were evaluated. Molar mass and root mean square radii averages, molar mass distribution as well as conformation of cellulose in 0.5% LiCl/DMAc, from both unaged and artificially aged papers, were studied. The latter was determined to be random coil for cellulose and vary slightly with the polymer molar mass.