The influence of alkali pretreatments in lyocell resin finishing – Fiber structure

The fiber structure was investigated in lyocell fabrics treated with NaOH (120 g/l), or KOH (250 g/l), and compared with that in untreated fabrics. The alkali treatments caused some degree of degradation in fibers, but no significant changes in carboxyl contents or crystallinity. There were indications of transitions of porosity in the morphology of lyocell fibers, with accessibility at the fiber centers being distinctly lower than that at the outer edges. Both alkali treatments appeared to increase accessibility at the peripheral region in fibers, though to different extents; but there were no evident changes of accessibility at fiber centers. A model is proposed of changes in fiber structure due to the two alkali treatments.