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 R 2 = 0.9214 was established using 29 datasets, confirming the model’s significance. Carbon disulfide (CS 2 ) 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, CS 2 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.