Synergistic Reinforcement of Gelatin Fibers by Lignin Incorporation and Drawing: Toward High-Performance and Ultraviolet-Resistant Textiles

Abstract Gelatin is a promising biobased feedstock for textile fibers but is plagued by inadequate mechanical properties. Lignin, which is abundant in polar groups, can act as a biomass reinforcing filler by forming hydrogen bonds with gelatin. However, the regulatory mechanism by which lignin content and draw ratio affect the structure and properties of gel-spun lignin/gelatin fibers remains unclear. In this work, the rheological behavior of the spinning dope was investigated to evaluate its spinnability, followed by a systematic exploration of the effects of lignin content and draw ratio on fiber properties. The fiber with 10% lignin content achieved a maximum draw ratio of 10 and optimal mechanical performance, with a tensile strength of 141.09 MPa, and a Young's modulus of 4.54 GPa. Under the synergistic effect of lignin incorporation and drawing, the helical structure of gelatin unwound, promoting the molecular chain orientation along the fiber axis and the formation of a denser, more ordered microstructure. Fabrics woven from these fibers exhibited excellent ultraviolet-resistant performance, with the optimal fabric achieving a high UPF value of 456.72. This work provides insights into the modulation of lignin/gelatin fiber for the development of high-performance functional textiles.