In situ crosslinked SiO2/BC ceramic nanofibrous aerogel with dual network structure for thermal insulation and sound absorption

The rapid development of modern transportation and industrialization has caused serious traffic noise pollution and energy consumption, posing a huge burden on the global economy, ecological environment, and human health. However, the narrow absorbing band, high density and poor mechanical durability of the sound-absorber and thermal insulation materials significant obstacles to its practical application. Herein, environment-friendly bacterial cellulose (BC) as the dispersant and binder to in-situ crosslinked SiO 2 nanofibers, resulting in SiO 2 /BC nanofibrous aerogel with dual-network via freeze drying. The hydrogen bonding within the BC allows SiO 2 nanofibers to hinge effectively, establishing a stable primary framework integrated with an in-situ secondary network. Benefit from synergistic effect of dual structure, the prepared aerogel exhibits 80% excellent compression recovery performance, with excellent fatigue resistance. Owing to their unique hierarchical, aerogel display superior low-frequency sound-absorbing capabilities and a high noise-reduction coefficient of 0.511. In addition, the dual network cell wall of aerogel provides large number of additional tortuous solid conduction paths for heat transfer, which showing ultralow thermal conductivities 28.14 mW/(m·K). Combined with the excellent mechanical performance, low thermal conductivity and excellent sound-absorption ability make it a promising material for heat insulation and acoustic absorption.