Kneader-assisted synthesis of high-substitution carboxymethyl sugarcane bagasse cellulose as a sustainable printing paste for reactive dye printing.

To develop a sustainable alternative to sodium alginate (SA) printing paste and achieve high-value utilization of agricultural biomass, sugarcane bagasse cellulose (SBC) was employed as the feedstock to prepare high-substitution carboxymethyl sugarcane cellulose (CM-SC) through a kneader-assisted two-step semi-dry etherification process. The effects of key processing parameters on etherification efficiency were systematically investigated, and CM-SC with a degree of substitution (DS) above 1.0 was successfully obtained. The structure-property relationship of CM-SC was further elucidated by evaluating the effects of DS on rheological behavior, water retention, storage stability, electrolyte tolerance, and practical printing performance. The results demonstrated that increasing DS progressively improved the shear resistance, water retention capability, storage stability, and compatibility with printing auxiliaries. In reactive dye printing applications, high-DS CM-SC samples (DS > 1.62) exhibited improved color strength (K/S value), reduced dye penetration, enhanced de-sizing efficiency, and favorable fabric handle properties compared with low-DS samples. Moreover, biodegradation evaluation indicated that high-DS CM-SC retained measurable biodegradation potential, although its biodegradability was lower than that of SA. Preliminary economic analysis further suggested its potential cost advantages. Overall, high-substitution CM-SC represents a promising biomass-derived printing paste with balanced performance, sustainability, and application potential as an alternative to conventional SA paste.