Research on the Impregnation Process and Mechanism of Silica Sol/Phenolic Resin Modified Poplar Wood

Phenolic resin impregnated modified materials have partially reduced the toughness of the wood. In this study, organic-inorganic composite modifiers were used to modify the wood. Silica sol/phenolic resin composite impregnating solution was prepared by an in-situ polymerization method and used to impregnate poplar wood under vacuum pressure. Orthogonal experiments were conducted, and the impact toughness of the modified poplar wood was used as the evaluation index. The results showed that the best impact toughness was achieved when the average particle size of silica sol was 8-15 nm, the pressure was 1.2 MPa, and the pressure time was 3 hours. The impact toughness of the impregnated modified poplar wood was improved by 84.1% compared to the untreated material. FT-IR results revealed the characteristic absorption peak of Si-O-Si in the impregnated poplar wood, confirming the formation of new chemical bonds. XPS analysis indicated that a chemical reaction occurred between the impregnating solution and the wood, resulting in the formation of Si-O-C. Furthermore, DMA analysis revealed that this chemical reaction significantly improved the thermal stability and toughness of the impregnated material, surpassing the original poplar wood. In addition, TG analysis revealed a significant improvement in thermal stability of the impregnated material compared to untreated poplar wood. Finally, SEM analysis demonstrated the successful infiltration and filling of the poplar wood by the composite impregnating solution.