Multifunctional lyocell fibers prepared by in-situ incorporation of nano-SiO2 via dope addition

This study presents a simple and effective strategy for fabricating multifunctional Lyocell fibers by dope addition of nano-SiO₂. Molecular simulations and experimental analyses indicated SiO₂ has little effect on the stability of N-methylmorpholine N-oxide (NMMO) solvent and Lyocell dope, supporting smooth spinning. Therefore, Lyocell-SiO₂ composite fibers containing up to 10 wt% nano-SiO₂ were prepared via dry-jet wet spinning. By the high-shear effect of nozzle, the Segre-Silberberg effect drives nano-SiO₂ migration toward the fiber surface, thereby enhancing its surface functionality. The results demonstrated that the introduction of 10 wt% nano-SiO₂ significantly enhanced multiple performance attributes of Lyocell fibers: flame retardancy was improved, with the limiting oxygen index (LOI) increasing from 19 % to 25 %; ultraviolet resistance and light-shielding properties was strengthened, as indicated by a ultraviolet protection factor value rising to 60; no fibrillation was observed after 30 min of ultrasound; and metal ion adsorption capacity was augmented. This work provides valuable insights into the development of functional Lyocell fibers using dope addition and nozzle high shear method and their multifunctional applications in textiles.