Influence of Swelling Media on the Crystallinity and Accessibility of Lyocell Fibers: An FTIR and 13C NMR Analysis

Cellulose swelling using different protic, aprotic and alkaline solvents, which are capable of penetrating crystalline parts of cellulose is one of the important methods to enhance the accessibility and, as a result, the reactivity of cellulose in modification reactions. Here we discuss changes in the structure of cellulose II in never-dried Lyocell fibers upon swelling with different solvents and aqueous solutions using FTIR as well as solid-state C-13 NMR spectroscopies and DSC thermal analysis. Changes in the water retention behavior and accessibility of fibers were correlated with solvent-related changes in the fiber structure and were in accordance with the results obtained by FTIR and C-13 NMR spectroscopies.

Automated summary

This study investigated the changes in cellulose II structure in never-dried Lyocell fibers upon swelling with different solvents and aqueous solutions using FTIR, solid-state C-13 NMR spectroscopies, and DSC thermal analysis. Water retention behavior and fiber accessibility were found to be correlated with solvent-induced changes in the fiber structure, in accordance with the results obtained from FTIR and C-13 NMR spectroscopies.