Chemical-composite bioenzyme synergistic degumming of Apocynum venetum L. fibers: Process optimization, mechanism and functional properties

Apocynum venetum L. (AV) fibers are promising functional bast fibers, but tightly bound surface gums must be removed to achieve spinnability. Herein, a synergistic chemical-composite enzymatic degumming system was developed to remove non-cellulosic impurities while preserving fiber functionality. The optimized process produced degummed AV fibers with a residual gum content of 3.60%, whiteness of 81.62%, single-fiber strength of 16.79 cN, and fiber length of 28.13 mm, meeting the requirements for spinning. The cellulose content increased from 44.68% to 89.84%, while pectin, hemicellulose, and lignin were substantially removed. FTIR, XRD, and TG analyses confirmed the retention of the cellulose I structure, an increased crystallinity index (82.63%), and improved thermal stability. Py-GC/MS further verified selective gum removal, as indicated by the increase in levoglucosan from 13.85% to 34.64% and the reduction of pyrolysis products derived from non-cellulosic components. Compared with conventional chemical degumming, the proposed process reduced chemical consumption and decreased wastewater COD by 94%. Moreover, the degummed fibers retained excellent antibacterial activity (>99% against E. coli and S. aureus ), together with measurable infrared-induced photothermal response and antioxidant properties. This work provides a cleaner and practically feasible route for the high-value utilization of AV fibers in functional textiles.