Structure tailoring and thermal performances of water glass-derived silica aerogel composite with high specific surface area and enhanced thermal stability

This research aimed to develop a low-cost, high-performance silica aerogel thermal insulation material. Silica aerogel (SA) with a specific surface area of 917 m²/g was synthesized from water glass via a facile one-pot sol-gel process. Silica aerogel composite (SAC) was prepared by wet impregnation of glass fiber felt. Comprehensive study on the structure evolution of the SA and SAC with temperature reveals the excellent stability of the SA and SAC at 700 °C. Thermal insulation performance of the SAC was comprehensively studied from different aspects, including thermal conductivity, thermal shield behavior under high temperatures, and thermal shock resistance. Thermal conductivities of the SAC containing silicon carbide (SiC) named SAC-SiC at 100–700 °C are lower than those of most reported aerogel composites as well as commercial tetraethyl orthosilicate-derived silica aerogel composites. Thermal shock with 1100 °C flame demonstrated excellent thermal stability and insulation performance of the SAC-SiC.