Enhancing fire resistance in wood with high-water retention silica gel: A promising flame-retardant solution

This study aims to evaluate water retention and flame-retardant properties of silica gel prepared using anionic polyacrylamide (HPAM), gluconate-delta-lactone (GDL) and aluminum citrate (AlCit). Silica gel samples were synthesized with sodium silicate (8 wt. %), sodium bicarbonate (4 wt. %) and varying concentrations of HPAM (0.2-0.8 wt. %) and GDL (0.1-0.3 wt. %). The prepared gels were characterized using XPS, XRD, FTIR and TGA. Optimal water retention capacity was achieved with 0.4 wt. % HPAM and 0.2 wt. % GDL. Compared to traditional gels, silica gel has more surface water molecules due to the additional hydrophilic groups and the amorphous nature of silica. At high temperatures, silica forms a layer with the charcoal from treated wood combustion, inhibiting oxygen penetration and minimizing further combustion. After combustion at 500 degrees C, the mass loss of wood treated with silica gel is 36-53 % less than untreated wood, indicating greater weight retention and demonstrating silica gel's effectiveness in preventing continued burning.