Synergistic regulation in aramid nanofiber-based composite aerogels for thermo-acoustic insulating applications

Ultralight aerogels are advanced materials with great potential for thermal insulation and noise reduction in the construction industry. The development of integrated thermoacoustic materials, combining thermal and acoustic insulation with sound absorption, is driven by diverse material choices and composite structural designs to enhance comfort and minimize noise. In this work, we developed an ultra-lightweight thermoacoustic synergistic aramid nanofiber aerogel that exhibits low thermal conductivity (0.034 W/(m*K)) with superior acoustic absorption and sound insulation capabilities. It was achieved by modulating the cross-linking agent content (waterborne polyurethanes) and inducing a bead-like pore structure among the internal nanofibers through a meticulous crushing-crosslinking-homogenizing casting process. Furthermore, we fabricated a bilayer composite perforated aerogel by employing a composite structure design. This structure demonstrated the high noise reduction coefficient (NRC) of 0.485 and the excellent average sound transmission loss (STL) of 18.4 dB across the frequency range of 800-6300 Hz. In conclusion, we prepared waterborne polyurethane/aramid aerogels by composite structure design, and then successfully engineered thermoacoustic composite aramid aerogels with a harmonized performance in thermal insulation, acoustic absorption, and sound insulation. The excellent performance of the thermoacoustic material holds the promise of being an innovative and efficient alternative to noise-reducing and insulating building materials.