Thermally Insulating SiO2/PSA Composite Aerogels with Heat Resistance and Mechanical Properties via the Thiol–Yne Click Reaction

Polymer-reinforced silica aerogels are thermally insulating materials employed to enhance mechanical properties; however, they exhibit low heat stability and require a complex production process. The main body of this work concerns the synthesis of silicon-containing polyarylacetylene (PSA) resin, which has exceptional thermal properties and is used to strengthen the gel skeleton and significantly improve the heat resistance of the polymer reinforcement phase. The honeycomb-like porous SiO2/PSA aerogels derived from directional freezing were obtained via click reaction, gel aging, freeze-drying, and curing without the requirement for time-consuming solvent replacement. The prepared SiO2/PSA aerogel is low density (∼0.3 g/cm3) and high porosity (∼80%), which provides the material with low levels of thermal conductivity (∼0.06 W/m·K) and excellent thermal insulation performance. When compared to the majority of polymer aerogels and aerogel-like materials, the prepared SiO2/PSA aerogels have high Td5 (∼460 °C) and Yr800 (∼80%) and compressive strength (compression strength > 1.5 MPa). SiO2/PSA composite aerogel has numerous functions in areas where materials must withstand extremely elevated temperatures, such as the aerospace industry.