Preparation of wood scrimber with low hygroscopicity and high flame retardancy through impregnation of silicon-boron inorganic salt

Abstract

Wood scrimber, known for its structural stability, strength, and efficient material utilization, faces significant flammability challenges that limit its application in construction and outdoor environments. To enhance fire safety in construction and meet building codes requirements, flame retardant treatment of wood scrimber is essential. Inspired by the honeycomb structure formed by propolis, beeswax, and intricate arrangements, flame-retardant wood scrimber materials were fabricated using phenolic resin adhesive, a flame retardant agent composed of a 1:1 mixture of sodium silicate (9-hydrate) and sodium tetraborate decahydrate, along with defibrated wood scrimber units. The treated wood scrimber exhibited self-extinguishing properties upon flame removal, with a 31 % reduction in peak heat release rate (pk-HRR₂), a 14.9 % reduction in total heat release (THR), a 38 % reduction in peak smoke production rate (pk-SPR), and a 43.7 % reduction in total smoke release (TSR), demonstrating a synergistic fire retardant effect between the silicon and boron compounds. Characterization through infrared spectral analysis (FTIR) and X-ray photoelectron spectroscopy (XPS) revealed that the cross-linked structure formed by sodium silicate and boric acid with the wood creates a dense char layer in the porous voids of the wood. The release of crystalline water at high temperatures further enhanced fire retardancy and reduced smoke production. This method holds promise for large-scale applications in construction and interior decoration, offering both fire resistance and low smoke emission.