A Computational Study on Acoustic Absorbance of Hydrophilic Cellulose Nanofiber Based Aerogel with Excellent Flame Retardant and Acoustic Insulation Property for Structural Building Applications

Abstract

The research aims to ensure the structural stability of nanocellulose-based aerogels in humid environments while imparting flame-retardant properties, alongside their inherent thermal and acoustic insulation capabilities. Building on the established flame retardancy of citric acid-based nanocellulose, our study marks a significant advancement by employing a simple and efficient methodological approach. We introduce a simple and facile technique for crosslinking CNF aerogel using a single crosslinking agent for extraction and modification. The cross-linked CNF aerogel shows a 91% porosity with a low density (0.15 g/cm³) which is also positively influenced by the morphological studies. In addition, the inclusion of citric acid into CNF improves water stability, mechanical performance (7.8 N/mm² for pure CNF and 8.9 N/mm² for cross-linked CNF aerogels), and thermal stability, while reducing the residue of the cross-linked material to 1.6% from 6.4% of pure CNF aerogel. The cross-linking of aerogel by citric acid could enhance fire resistance by lowering the production of hazardous and combustible gases. Furthermore, the cross-linked CNF aerogel was evaluated with a thickness of 40 mm, as the pure CNF aerogel demonstrated optimal sound absorption behavior at this thickness according to simulations conducted using COMSOL Multiphysics software. This work contributes to the broader understanding of how nanocellulose can be engineered for structural building applications, paving the way for further innovations in environmentally friendly aerogel technologies.

Graphical Abstract