Redispersion of dried plant nanocellulose: A review

Abstract

Nanocellulose has undergone substantial development as a high value-added cellulose product with broad applications. Dried products are advantageous to decrease transportation costs. However, dried nanocellulose has redispersion challenges when rewetting. In this work, drying techniques, factors affecting redispersibility, and strategies improving the nanocellulose redispersibility are comprehensively reviewed. Hydrogen bonds of nanocellulose are unavoidably developed during drying, leading to inferior redispersibility of dried nanocellulose, even hornification. Drying processes of nanocellulose are discussed first. Then, factors affecting redispersibility are discussed. Following that, strategies improving the nanocellulose redispersibility are analyzed and their advantages and disadvantages are highlighted. Surface charge modification and steric hindrance concept are two main pathways to overcome the redispersion challenge, which are mainly carried out by chemical modification, additive incorporation and non-cellulosic component preservation. Despite several advancements having been achieved, new approaches for enhancing the nanocellulose redispersibility are still required to promote the industrial-scale applications of nanocellulose in various domains.

Keywords: Additives; Chemical modification; Drying; Nanocellulose redispersibility; Steric hindrance; Surface charge.