From Hemp Bast to Lyocell Fiber: Sustainable Process Optimization for Lyocell‐Grade Dissolving Pulp

ABSTRACT The growing demand for sustainable cellulose textile fibers drives the search for alternative raw materials and potentially more sustainable pulping methods. This study presents a modified pre‐hydrolysis kraft (PHK) process, free of chlorine, sulfur, and strong acids, to prepare lyocell‐grade dissolving pulp from Canadian hemp bast fiber (cultivar: ANKA). The optimized pulping method comprises sodium hydroxide alkali treatment, mild chelation, and totally chlorine‐free (TCF) alkaline hydrogen peroxide bleaching while omitting the pre‐hydrolysis stage. The produced pulp achieved 97% α‐cellulose, 3.3% hemicellulose, and < 0.1% lignin, with an intrinsic viscosity of 3.05 dL/g, suitable for lyocell fiber manufacturing. Transition metal content was below 10 ppm, and alkali and alkaline earth metal concentrations were under 100 ppm. The pulp dissolved in aqueous N‐methylmorpholine N‐oxide (NMMO) to form a homogeneous spinning solution. Lab‐scale spinning yielded continuous hemp‐based lyocell fibers with smooth surfaces, uniform cross‐sections, and crystallinity values typical of undrawn regenerated cellulose fiber. The results demonstrate that this optimized process enables hemp bast, a non‐wood fiber source, to serve as an effective feedstock for lyocell fiber production. This approach helps bridge the global cellulose gap while providing a potentially more sustainable alternative to conventional wood and cotton sources.