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

Abstract

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°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.

Keywords

• polyacrylamide
• microscopic process
• combustion morphology
• mass loss
• amorphous silica