Adding lignin to bagasse cellulose-based materials increases the wet strength and reduces micro-nano scale wet low-temperature defects

The enhancement of cellulose utilization in agricultural by-products, such as bagasse, holds significant importance in augmenting the value of secondary agricultural products. However, cellulose-based materials have limited application potential owing to their low strengths under wet and wet-low-temperature conditions. Improved mechanical properties of cellulose-based materials at wet and low temperatures can significantly enhance their suitability for application in cold chain processes. Furthermore, the effects of wet cryogenic conditions on cellulose-based materials are not well understood. In this study, composite films composed entirely of biomass are prepared via the co-solubilization of lignin and bagasse cellulose and then cured via hot pressing, which increases the wet and wet low-temperature strengths of the films. Furthermore, the mechanism by which cellulose/ lignin content influences the wet-low-temperature defects of films was investigated. Lignin self-polymerizes and hot pressing causes cross-linking in the cellulose-based films, which improves their performance in wet low-temperature environments. Furthermore, the micromorphologies, specific surface areas, and moisture distribution patterns of the cellulose films after wet -low-temperature treatment were investigated. The results indicate that cross-linking prevents large amounts of micro-nano scale free-water from entering the cellulose-based material, thereby preventing the formation of ice crystals at low temperatures, which can damage the microstructure. The results of this study can be used to develop bagasse cellulose/cellulose-based materials for applications in humid and low-temperature environments.