An energy efficient one-pot swelling/esterification method to prepared cellulose nanofiber with uniform diameter

An energy-efficient method has been developed to prepare3–5 nm-wide carboxyl-functionalized cellulose nanofibers(CNFs) from pulp fiber by a simple one-pot swelling followedby esterification process. Tetrabutylammonium acetate (TBAA)/dimethyl sulfoxide (DMSO) binary solvent is used as the swel_x0002_ling agent and the esterification medium admixed with maleicanhydride. All steps are performed at room temperature andno post-mechanical treatment is needed. The highly efficientdefibrillation of pulp fiber to CNFs is thought to be due to twofactors: 1) swelling in TBAA/DMSO effectively loosens the structure of cellulose supermolecules by breaking the intra- and in_x0002_termolecular hydrogen bonds between cellulose chains； and2) the carboxyl groups grafted onto the cellulose molecules byesterification prohibit the reformulation of hydrogen bonds between cellulose chains and therefore stabilize the disperseCNFs with uniform diameter in solution.