Multifunctional Phenolic Aerogels: Molecular Engineering Strategies for Next-Generation Thermal Protection Systems

The pursuit of lightweight thermal protection systems has driven phenolic aerogels into the forefront of materials research owing to their excellent thermal insulation and ablation resistance properties. This paper introduces methods for preparing phenolic aerogel with thermosetting and thermoplastic phenolic resins as raw materials and discusses the development direction of ambient pressure drying technology, providing ideas for low-cost and large-scale preparation. Methods for modifying phenolic aerogel through molecular structure design are analyzed, suggesting that multielement synergistic hybridization can significantly improve the oxidation resistance and ablation resistance of phenolic aerogel. The preparation methods and properties of phenolic aerogel composites prepared using fibers and fillers as reinforcing phases are reviewed, expounding the influence of the reinforcing phase and its interface modification on the properties of the composites. Subsequently, the strategic design of a multifunctional phenolic aerogel was also deeply discussed. Based on the above progress, it is believed that future research in this field will focus on the molecular structure design of phenolic resin, special structural regulation of the reinforcing phase, and the development of multifunctional integration.