Ambient Pressure Drying for Fabrication of Cellulose-Based Lightweight Porous Materials: A Review.

The depletion of fossil resources and environmental pollution issues have accelerated the development of biomass-based lightweight porous materials. Cellulose-based lightweight porous materials (CLPMs) have emerged as ideal alternatives to petroleum-based porous materials owing to their advantages of renewability and biodegradability. Ambient pressure drying has become an ideal solution for the large-scale production of CLPMs; owing to its low cost, short processing time, and ease of operation. However, challenges such as strong capillary forces, reorganization of intermolecular hydrogen bonds, and insufficient framework strength can lead to the collapse of the porous structure during the drying process. This review systematically summarizes the research progress of ambient pressure drying techniques for CLPMs, providing an in-depth analysis of the intrinsic mechanisms underlying structural collapse in terms of capillary pressure, hydrogen bond reorganization, and structural strength. Based on this analysis, five major control strategies for ambient pressure drying, such as solvent substitution and surface hydrophobic modification, are outlined. Furthermore, this review comprehensively discusses the practical application prospects of such materials in adsorption, thermal insulation, and other fields. This review aims to provide theoretical references for the development and industrialization of CLPMs.