Thermal Insulation, Sound Absorption, and Antibacterial Bamboo Cellulose Aerogel via Schiff Base Cross-Linking with Ambient Pressure Drying Technique

Cellulose aerogels have become the most promising foam substitutes due to their lightweight and porous nature, green and sustainable raw materials, and good environmental compatibility. However, the complexity of the preparation process and the poor mechanical, thermal insulation, sound absorption, and antimicrobial properties have limited their practical applications. The skeletal strength of aerogels is enhanced through a Schiff base cross-linking reaction between glutaraldehyde (GA) and polyethylenimine (PEI). In addition, the generated Schiff base imparts the antimicrobial properties of the aerogel. Bamboo cellulose aerogel with high mechanical strength, thermal insulation, sound absorption, and antibacterial properties was prepared via a simple ambient pressure drying technology. The resulting aerogel (PG aerogel) shows a low volumetric shrinkage (15.4%), high porosity (95.8%), low density (55 mg/cm3), and low thermal conductivity as low as 34.5 mW/(m·K). The aerogel exhibits a high compressive strength of 1.52 MPa and good thermal insulation at 100 and 200 °C heating platforms. The acoustic absorption coefficient reaches 0.823 in the frequency range of 3000 to 6000 Hz and exhibits a bactericidal efficiency of up to 99% against Escherichia coli and Staphylococcus aureus. This work provides novel inspiration for the development of cellulose aerogels and demonstrates the enormous potential of cellulose aerogels in fields such as construction, traffic noise reduction, and hygiene protection.