Preparation and characterization of thermal protective aluminum hydroxide aerogel/PSA fabric composites

In this work, aluminum hydroxide aerogel was successfully assembled on polysulfonamide fabrics by sol–gel forming method to improve the thermal insulation and flame resistance properties. The presence of aluminum hydroxide aerogels assembled on the surface of polysulfonamide fabrics was verified by the scanning electron microscopy. The aerogel was crystalized in γ-AlOOH boehmite form characterized by X-ray powder diffraction. The heat insulation and flame resistance of polysulfonamide fabrics were improved by coating aluminum hydroxide aerogels. When the molar ratio of propylene oxide to aluminum chloride hexahydrate was 4:1, the prepared aluminum hydroxide aerogel marked as SAl-2 had the largest pore volume with the value of 2.33 cm3/g, the corresponding apparent density was 0.172 g/cm3, the specific surface area was 392 m2/g, the average pore diameter was 18.6 nm, and it gave the best thermal insulation property. Compared with the original polysulfonamide fabric, the thermal conductivity of the composite fabric was decreased from 0.0513 to 0.0301 W/(m·K). When the molar ratio of propylene oxide to aluminum chloride hexahydrate was 3:1, the prepared aluminum hydroxide aerogel marked as SAl-1 had the smallest pore volume with the value of 0.72 cm3/g, the corresponding apparent density was 0.645 g/cm3, the specific surface area was 293 m2/g, the average pore diameter was 10.9 nm, and it gave the best flame resistance property. Compared with the original polysulfonamide fabric, the vertical burning damage length was shorted from 4.90 to 1.30 cm.