Hybrid aerogel composites reinforced with aramid fiber fabric for thermal protection

A novel method for improving the thermal protection performance of protective materials in high temperature flame environment was provided. The aramid fiber fabric reinforced hybrid silica aerogel composite (AF-HSiO2) was prepared by the two-step sol-gel method using AF nonwovens as the three-dimensional reinforced materials, deionized water as the sole solvent and hybrid silica aerogel (HSiO2) as the growth substrate followed by freeze-drying method (FD). The resulted composites perfectly owned their nano porous structure and excellent properties of high porous (81.12%), low bulk density (0.1612 g cm−3) and large surface area (659 m2 g−1). In addition, when the composite was exposed to a high heat flux of 84 ± 2 kW m−2, the thermal protection performance increased by 27.97% compared with the commercial thermal liner of fire-fighting clothing. The nature also endowed the composites with tensile strength (319.2 N) and hydrophobic angle (136°). These favorable multi-features indicate that composites have broad prospects in thermal protection filed. Graphical abstract