Research progress on improving dispersion stability of nanocellulose in different media: A review

Nanocellulose has been widely used in various fields due to its good biocompatibility, mechanical properties, large specific surface area and environmental friendliness. Among these applications, uniformly dispersing nanocellulose in various media to improve its performance is an application with good development prospects. However, due to the presence of surface hydroxyl groups, nanocellulose tends to form aggregates between molecular chains and is less compatible with nonpolar solvents, thus making it difficult to be stably dispersed in solvents. How to break the aggregation between cellulose and improve its compatibility with the medium has become a challenging issue. In this paper, the dispersion system is classified into polar medium, nonpolar medium and polymer matrix according to the polarity and state of the medium, and a review is presented on how to improve the dispersion stability of nanocellulose in different media. The methods of using surface modification to improve the dispersion stability of nanocellulose in different media, such as carboxylation, amidation, and grafting of long-chain molecules to reduce the aggregation among nanocellulose and to improve the compatibility with solvents, are highlighted. Finally, suggestions are made for future research directions.