Green degumming of industrial hemp fibers: Property enhancement and application in hemp/cotton blended yarns

Waste fibers generated during hemp fiber processing (hemp noil) are often disposed of as solid waste due to inadequate treatment technologies, causing resource waste and failing to meet the demand for high-quality fibers in yarn production. To achieve efficient recovery and high-value utilization of hemp noil, and explore a green refined process suitable for yarn production, this study uses hemp noil as raw material and proposes a green refining process: polyethylene glycol/water pretreatment, composite enzyme degumming, and sodium percarbonate bleaching. The optimal conditions are: polyethylene glycol/water mass ratio 0.2:1, bath ratio 1:50, treatment at 25 ℃ for 60 min. Results show the contents of reducing sugar, total sugar, free phenolic hydroxyl groups in the solution, and fiber whiteness are 71.06%, 23.66%, 39.49%, and 33.25% respectively, achieving the optimal overall effect—an increase of more than 30% compared with the traditional chemical pretreatment process (whiteness 22%-25%). The degummed cotton-type industrial hemp fibers have a breaking strength of 10.73 cN and fineness of 0.28 tex, significantly superior to single-enzyme degummed products (fineness > 0.4 tex, strength > 7 cN). The response surface optimization results are reasonable and feasible. Blended with cotton at 70/30 ratio on cotton spinning equipment, the blended yarn exhibits an evenness CV value of 16.59%, breaking force of 315 cN, and breaking strength of 9.2 cN/dtex, 22.7% higher than pure hemp yarn (7.5 cN/dtex), indicating good spinnability. This environmentally friendly process provides a green solution for the refined processing of industrial hemp fibers. • Recycling and Utilization of Industrial Waste Fibers. • Green Degumming Process for Hemp Fibers. • High-performance hemp-cotton blended yarn via cotton spinning.