Study on the Reconstruction of Three-Dimensional Network and Performance of Phenolic Aerogels Induced by Dual-Functional Silane Design

The inherent brittleness of phenolic aerogels significantly limits their application expansion in aerospace thermal protection. A bifunctional silicone prepolymer with both reactivity and flexibility was synthesized by the prereaction of 3-(2,3-epoxypropoxy)propyltrimethoxysilane and methyltrimethoxysilane. Its strong interfacial bonding with the phenolic network formed thick-walled nanostructures, achieving molecular-level compatibility between organosilicon and phenolic materials while enabling efficient stress transfer. Simultaneously introduced flexible segments toughen and refine the microstructure, reconstructing the three-dimensional network of the phenolic aerogel to mitigate brittleness. Results demonstrate that the silicone/phenolic aerogel exhibits a uniform, stable porous structure with low density (0.27 g/cm 3 ) and low room-temperature thermal conductivity (0.0458 W/(m·K)). While enhancing toughness, its compressive strength increases by 215% compared to that of pure phenolic aerogel. The phenolic aerogel prepared via this simplified strategy demonstrates significant potential for practical applications.