Lightweight Composite Aramid Nanofiber Aerogel With Multistage Pores and Layered Structure for Acoustic and Thermal Insulation

ABSTRACT Aerogels are currently advanced multifunctional sound‐absorbing materials. Aramid nanofiber aerogels (ANFs) also possess lightweight and excellent thermal insulation properties, making them high‐performance materials for extreme environments with broad application prospects. In this study, aramid fibers were used as raw materials, which were uniformly mixed with surfactants and cross‐linkers, followed by ultrasonic pulverization treatment to fabricate multilayered porous hierarchical composite aramid nanofiber aerogels (MPL‐ANFs). The results show that MPL‐ANFs not only retain the lightweight and excellent thermal insulation properties of ANFs but also form a hierarchical porous structure that effectively absorbs sound. Specifically, MPL‐ANFs with a surfactant‐to‐aramid fiber weight ratio of 1:1 exhibit excellent acoustic properties, with a noise reduction coefficient of 0.52 and an average sound absorption coefficient of 0.71. MPL‐ANFs also demonstrate flame retardant and superior thermal insulation properties, with a thermal conductivity of 0.0368 W/(m*K). After heating on a 120°C heat plate, the sound absorption performance of the aerogel remains largely unchanged. This work significantly enhances the potential of ANFs as novel acoustic materials, broadening their application prospects.