Structural Characterization and Properties of Lyocell Fibers After Fibrillation and Enzymatic Defibrillation Finishing Treatments

Abstract

The mechanical, structural, and dyeing properties of solvent-spun lyocell fibers in a plain weave fabric are studied before and after industrial treatments of mechanical fibrillation and enzymatic defibrillation. Stress-strain relationships, surface morphology, crystallinity, and dye uptake are assessed for each of the samples and compared. Both treatments significantly decrease the tensile failure properties of the yarns. There are no appreciable changes in the Young's modulus, nor are there significant differences in yarn linear density or fiber diameter. Fourier transform infrared spectroscopy and x-ray diffraction results identify the crystalline morphology of the lyocell fibers as cellulose II. Spectroscopy results indicate that a small decrease in crystallinity takes place with industrial processing. The rate of decreased fiber crystallinity during ball milling is facilitated by the fibrillation and enzymatic treatments. Compared to the untreated fabric, both treated fabrics exhibit increased dye uptake rates, which appear to be greatest after fibrillation.