Constructing powerful interface between glass fiber and silica aerogel via an interfacial molecular bridge allows for excellent acoustic-thermal insulation composites

Fiber reinforcement is a general approach toward the strengthening of silica aerogel in large-scale applications. However, the interface between the fiber and the aerogel is weak, limiting its practical use. Extensive study and attempts have been done to demonstrate that chemical crosslinking is an efficient method for interface bonding between silica aerogel and glass fiber, especially when using silane coupling agents containing amino groups. Here, a simple synthetic approach is presented to synthesize silica aerogel and its composite via alkali-reduced direct gel method, with N-(2-aminoethyl)-3-aminopropyltrimethoxysilane (KH792) serving as a bridge between silica aerogel and glass fiber, preparing KH792@silica aerogel (KSA) and KH792@silica aerogel/glass fiber felt composite (KSGF). Thermal insulation and acoustic properties of KSGF are characterized by a thermal conductivity tester and an impedance tube. Increasing the concentration of KH792 improves the mechanical characteristics of KSGF, with a maximum improvement of 178 %. At the same time, benefiting from the heat-insulating and acoustic delay characteristics of silica aerogel, KSGF exhibits excellent thermal insulation (thermal conductivity of 0.0358 W·m⁻¹·K⁻¹) and acoustical insulation properties (the maximum sound transmission loss of 26.96 dB). The outstanding comprehensive performance of KSGF makes it highly promising for developing high-strength, and acoustic-thermal materials in the construction industry, transportation, and aerospace.