Influence of cross-section shape on structure and properties of Lyocell fibers

Three kinds of Lyocell fibers with different cross-sections including circular, H-shape, and Y-shape (abbreviated as O-, H-, and Y-Lyocell) were prepared by a dry-jet wet spinning method. The effects of cross-sectional shape on structure and properties of Lyocell fibers were evaluated. The results showed H-Lyocell and Y-Lyocell exhibited triangular and dumbbell cross-sections, respectively, due to die swell. Both non-roundness factor and crystallinity of different cross-sectional Lyocell fibers were in the order of H-Lyocell > Y-Lyocell > O-Lyocell. All cross-sectional Lyocell fibers showed similar values of fineness and tensile strength. The profiled Lyocell fibers were superior to circular Lyocell fibers in terms of luster, dyeing properties, and moisture regain. The dye uptake and fixation rate of Lyocell fibers were influenced by shape in the order H-Lyocell > Y-Lyocell > O-Lyocell; while for luster and moisture regain the order was Y-Lyocell > H-Lyocell > O-Lyocell. Profiled Lyocell fibers are expected to open broader prospects in different textile or composite fields due to their various advantages versus conventional circular Lyocell fibers.