A new recognition of the binding of cellulose fibrils in papermaking by probing interaction between nanocellulose and cationic hemicellulose

Abstract

Abstract The paper industry is constantly seeking innovative ways to improve paper quality, increase process efficiency and reduce environmental impact. The unique properties of cationic modification of hemicellulose provide an opportunity to achieve these goals. Herein, eucalyptus hemicellulose was modified with quaternary ammonium groups to yield cationic hemicellulose (CH), which was used to elaborate structural and functional interactions between CH and cellulose nanofibrils (CNF). These interactions were quantitatively monitored by a quartz crystal microbalance with dissipation (QCM-D). We empirically studied bonding motifs between CNF and hemicellulose by forming films. The degree of substitution (DS) of CH was made between 0.095 and 0.254 by varying the molar ratio of the reaction, leading to a gamut of positive charges in hemicellulose. The adsorption of CH to a CNF surface was related to electrostatic interactions. The high DS of CH had higher adsorption rate and larger adsorption capacity within the CNF-surface, while CH as a reinforcing agent significantly increased the tensile strength of the film by hydrogen bonding, which was 71% higher than that of unmodified hemicellulose. The strong binding between CH and nanocellulose may highlight a platform to develop paper additives and nanocellulose composites for high-value applications.