Regulating and Controlling the Microstructure of Nanocellulose Aerogels by Varying the Intensity of Hydrogen Bonds

Abstract

Because of the fascinating properties and tremendous application potential of nanocellulose aerogels (CAs), research into them has exploded. However, regulating and controlling their microstructure remain challenging. Herein, the strategy of regulating the strength of hydrogen bonding was used to investigate the cause of cellulose nanofiber (CNF) aggregation. Three kinds of silane coupling agents with different tail functional groups were employed to modify CNFs. The hydrogen bond fraction of CAs decreased from 0.41 to 0.33, indicating a decrease in the intensity of hydrogen bonding. Also, the CA with a 3D-web-like structure was obtained. The specific surface area of the aerogels increased from 44.36 to 99.37 m2/g, showing that the aggregation was limited. In parallel, superior mechanical properties and thermal insulation were obtained. These results showed that varying the intensity of the hydrogen bond could inhibit the aggregation of the CA skeleton structure. The improvement of the specific surface area will expand its application in catalyst support, environmental remediation, heat insulation, and other fields. This method paved the way for future studies on the control of the micro-structure of CAs.