Production of cationic nanofibrils of cellulose by twin-screw extrusion

Cationization of cellulose fibers introduces positives charges and thus decreases the energy consumption to produce cellulose nanofibrils (CNF), improves their quality and confers them antimicrobial properties. In this study, cationic CNF at 17 wt% solid content were produced for the first time using an energy efficient process: the twin-screw extrusion (TSE). The production was compared to the production of enzymatic CNF using the same mechanical treatment and the efficiency of cationization was discussed. CNF produced were characterized using different techniques such as optical microscopy, atomic force microscopy, mechanical properties or transparency and finally classified using the quality index. Despite a slipping effect in the TSE which leads to intact residual fibers, highly transparent CNF with high Young's modulus (10 GPa) and suitable quality index were obtained consuming only 1100 kW h/t. Activity of cationized CNF to limit bacteria proliferation has even been confirmed.