Nanocellulose-based lightweight porous materials: A review

Nanocellulose has been widely concerned and applied in recent years. Because of its high aspect ratio, large specific surface area, good modifiability, high mechanical strength, renewability and biodegradability, nanocellulose is particularly suitable as a base for constructing lightweight porous materials. This review summarizes the preparation methods and applications of nanocellulose-based lightweight porous materials including aemgels, cryogels, xemgels, foams and sponges. The preparation of nanocellulose-based lightweight porous materials usually involves gelation and drying processes. The characteristics and influencing factors of three main drying methods including freeze, supercritical and evaporation drying are reviewed. In addition, the mechanism of physical and chemical crosslinking during gelation and the effect on the structure and properties of the porous materials in different drying methods are especially focused on. This contribution also introduces the application of nanocellulose-based lightweight porous materials in the fields of adsorption, biomedicine, energy storage, thermal insulation and sound absorption, flame retardancy and catalysis.

Automated summary

Nanocellulose, with its unique properties and versatile applications, has been extensively studied as a promising base material for lightweight porous materials. The preparation methods, including gelation and drying processes, as well as the characteristics and influencing factors of different drying methods, play essential roles in determining the structure and properties of nanocellulose-based lightweight porous materials. The applications of nanocellulose-based lightweight porous materials in various fields such as adsorption, biomedicine, energy storage, thermal insulation, sound absorption, flame retardancy, and catalysis are also highlighted in this review.