Double-cross-linking strategy for preparing flexible, robust and multifunctional cellulose aerogels

Cellulose aerogels, known for their biocompatibility and biodegradability, often suffer from poor mechanical properties, limiting their practical use. In this study, a double cross-linking strategy was employed using poly(vinyl alcohol) (PVA) and 3-aminopropyltriethoxysilane (KH550) to reinforce cellulose aerogels, forming a stable 3D network through hydrogen and chemical bonding. The resulting aerogel exhibits remarkable mechanical strength, with a compressive stress of 2.16 MPa at 80 % strain, an 854 % improvement over pure cellulose aerogels (CA). PVA/KH550 cross-linked CA aerogel also shows excellent durability, maintaining 82 % strain recovery after 30 cycles at 50 % strain. The PVA/KH550 cross-linked aerogel demonstrates excellent acoustic and thermal insulation properties. The PVA/KH550 cross-linked CA effectively attenuates sound transmission with an average sound transmission loss of 34.35 dB across the frequency range of 800–6300 Hz under an intensity of sound source of 85 dB. Additionally, the aerogel exhibits outstanding thermal insulation with low thermal conductivity of 0.0324 W/m·K. The aerogel shows a promising potential for robust, energy-efficient, lightweight, fireproof, and sound insulation materials.