Research on optimization of substitution degree of xanthated cellulose fiber and pretreatment process for defibration

This study focuses on xanthated cellulose fiber (XCF), a precursor of cellulose nanofiber (CNF), innovatively integrates orthogonal experiments, two-factor analysis of variance, stepwise regression, and particle swarm optimization to systematically analyze and precisely control its degree of substitution (DS). Based on a three-level four-factor orthogonal design and supplementary tests, a quadratic nonlinear regression model with R2 = 0.9214 was established using 29 datasets, confirming the model’s significance. Carbon disulfide (CS2) dosage was identified as the most influential factor, and all six interaction terms were statistically significant. The optimal process parameters obtained via particle swarm optimization were: NaOH concentration 7.47%, alkali treatment time 4.38 h, CS2 dosage 0.53 mL, and xanthation time 2.74 h. A verification experiment under these conditions yielded a DS of 0.972, with only a 2.8% deviation from the predicted value. This study provides a precise and controllable pretreatment strategy for the efficient and low-energy preparation of CNF, demonstrating significant potential for industrial application.