Tuning the Degree of Protonation to Prepare Ultra-light and High Thermal Insulation Mullite Nanofiber Aerogels

Abstract

Ceramic fiber aerogels play an important role in thermal insulation due to their high specific surface area and porosity. They have great potential in aircraft, the military industry, and metal smelting. Although traditional ceramic fiber has the advantages of high-temperature resistance, its brittleness, tensile resistance, and high production cost, greatly limit the application of ceramic aerogels. Using the sol-gel method and electrostatic spinning technique, we controlled the fibers’ random winding and mechanical properties by controlling the protonation of the spinning fluid. We prepared ultralightweight, flexible, and highly insulated mullite nanofiber aerogels with a volume density as low as 7 mg / cm3, thermal conductivity as low as 27 mW m−1 K−1, excellent thermal stability at 1,300 °C, high thermal insulation and retention of up to 50% of the ceramic fiber after initial compression. This material’s fabrication process and excellent insulation properties propose new opinions on the lightweight and durable insulation materials needed for aerospace and military insulation.