Double Cross-Linking Strategy for High-Performance, Thermally Stable Aerogels: A Breakthrough in Extreme Environment Applications

Abstract

High-performance insulating aerogels are optimal thermal protection materials for extreme environments such as aerospace. However, the large-scale application of traditional inorganic aerogels is constrained by their brittleness, hygroscopicity, and complex process conditions. Furthermore, the temperature resistance of organic aerogels is limited, despite their high mechanical strength and low-cost advantages. In this study, a composite aerogel material with a double cross-linking structure and strong interactions was successfully prepared by acid-catalysed ring-opening and supercritical drying processes using methyltrimethoxysilane as the silicon source, combined with phenylaminoated polybenzoxazine monomers and carboxylated cellulose nanofibers as the reinforcement materials, and introducing fumed hydrophobic silica. The material displays excellent mechanical properties, with a compressive strength of up to 34 MPa, and is capable of withstanding more than 500 ml of water without significant deformation. Furthermore, the aerogel exhibits a low density (0.175–0.232 g/cm³), good hydrophobicity (contact angle of 142°), and excellent thermal stability. This study presents a novel approach to the development of thermal protection materials that combine high strength and excellent thermal insulation properties.