Study on properties of SiO2 mineralized delignification and hydrogel treated poplar wood composites

Abstract

In this study, the natural biomineralization process was simulated using NaClO₂ to remove lignin, thereby exposing the cellulose skeleton of poplar. The biocompatibility was enhanced through gelatin gel impregnation, which provided nucleation sites for subsequent SiO₂ mineralization. The in-situ mineralization of SiO₂ within the cell wall and cell cavity of poplar was achieved via the sol-gel method, utilizing tetraethyl orthosilicate as the silicon source, in conjunction with pH adjustment and a low-voltage electrostatic field. Consequently, SiO₂ mineralized delignification and hydrogel treated poplar wood composites (SDP) were prepared, featuring SiO₂ mineralized delignification and hydrogel treatment. The detection and analysis of the physical performance indicators of SDP revealed a weight% gain of 12.56%, an increase in absolute dry density, and significantly reduced radial and chordwise saturated water swelling rates and water absorption rates. Surface color and glossiness analyses indicated that the color of SDP darkened and its glossiness decreased. The water contact angle test demonstrated an enhancement in the hydrophilicity of the SDP surface. Fourier transform infrared spectroscopy analysis confirmed the formation of organic-inorganic hybrid structures between SiO₂ and poplar wood. Thermogravimetric analysis indicated that SDP exhibited improved thermal stability and increased activation energy, suggesting a more stable chemical structure and a more challenging pyrolysis reaction. Scanning electron microscopy and X-ray energy dispersive spectrometry revealed a uniform distribution of SiO₂ within SDP, resulting in a dense SiO₂ film layer and filler. This study presented a novel method for enhancing the performance and added value of fast-growing poplar wood, offering a new strategy for the development of high-performance biomass composite materials.