Dyeing of Hemicellulose‐Rich Man‐Made Cellulosic Fibers Using Reactive Dyes

ABSTRACT The utilization of hemicellulose in fiber production offers a sustainable route for textiles by transforming an otherwise wasted component of wood biomass into value‐added material. The high hemicellulose content in these fibers poses challenges for alkaline wet processing, particularly during dyeing with reactive dyes. This study provides a systematic evaluation of how different alkaline conditions influence both the structural stability and dyeability of hemicellulose‐rich (HR‐Cell) fibers, addressing a knowledge gap in the processing of next‐generation biobased cellulosic fibers. We investigate the dyeability and structural stability of HR‐Cell fibers under sodium hydroxide (NaOH, 5–10 g/L) and sodium carbonate (Na 2 CO 3 , 5–20 g/L) treatments. Comprehensive characterization of HR‐Cell fibers, including carbohydrate analysis, molar mass distribution, intrinsic viscosity, degree of polymerization, and crystallinity, showed that NaOH at 10 g/L led to hemicellulose degradation and cellulose depolymerization, whereas Na 2 CO 3 preserved hemicellulose even at elevated concentrations. Dyeing experiments using C.I. Reactive Red 141 and C.I. Reactive Yellow 6 revealed that HR‐Cell fibers consistently exhibited higher dye exhaustion, fixation, and color strength compared to cotton, viscose, and Lyocell fibers. The most favorable dyeing results were achieved with 15 g/L Na 2 CO 3 , which offered optimal conditions for activating fiber hydroxy groups, minimizing dye hydrolysis, and preserving hemicellulose in the fibers. Colorfastness tests confirmed very good to excellent resistance to washing, rubbing, and light across all samples and conditions.