Water-assisted fabrication of fabric-reinforced polybenzoxazine aerogel composite for fire resistance and thermal insulation under harsh conditions

Polybenzoxazine-based aerogel composites have attracted much attention as intrinsic fire-retardant thermal insulation materials. However, their promotion in the thermal management field is currently constrained by the prevalent use of hazardous solvents and the requirement of high temperatures or high-active catalysts during preparation. Herein, a novel needle quartz fiber felt-enhanced polybenzoxazine aerogel composite (NQF/WPBzAC) was prepared using deionized water as the solvent combined with ambient pressure drying, wherein a binary monomer gelation strategy was employed to induce the sol-gel transition occurred under mild and catalyst-free conditions. The resultant NQF/WPBzAC exhibited integrated characterizes of lightweight (0.324 g cm⁻³), efficient thermal insulation (0.055 W m⁻¹ K⁻¹), good compressive and flexural resistance, and excellent fire retardance. Repeated water immersion tests and high-temperature exposure tests were carried out to assess the durability of NQF/WPBzAC in harsh environments. This research provides insights into the green and gentle preparation of polybenzoxazine-based aerogel composites applicable for fire resistance and thermal insulation.