Bio-based hierarchical natural fibre composites based on cellulose nanocrystal modified luffa structures for acoustic panels
Topic(s) : Material and Structural Behavior - Simulation & Testing
Co-authors :
Shahed EKBATANI (UNITED KINGDOM), Dimitrios PAPAGEORGIOU (UNITED KINGDOM), Han ZHANG (UNITED KINGDOM)Abstract :
The use of modern materials that provide improved sound absorption has become necessary due to the significant health risks associated with noise pollution [1]. One typical method of noise reduction is the use of porous materials, such as polyurethane foams [2], which have the unique property of converting sound waves into heat [3].
The selection of acoustic materials is undergoing a significant change towards bio-based alternatives, mostly due to the negative environmental and health effects linked to synthetic options like polyurethane (PU) foam. This study explores the use of natural porous luffa as the sound absorption materials, with locally deposited cellulose nanocrystals (CNC) to achieve a hierarchical natural fibre composite. The effect of CNC loadings on acoustic properties have been systematically examined via impedance tube method based on ASTM C384 [4] and compared with the commercially available PU panels. The modification of luffa with 3 wt.% CNC resulted in a 13% increase in the average sound absorption coefficient across the 300 Hz to 2000 Hz frequency range compared to unmodified luffa. The absorption coefficients at low panel thickness ranges exhibit a significant enhancement compared to the unmodified luffa and PU foam. Due to their large surface area, CNCs can efficiently adhere to the cellular walls of the luffa structure. This adherence can potentially increase the density and complexity of the luffa's internal network. The proposed alterations to the micro-architecture are expected to enhance the reduction of sound wave interference and absorption in the material, thus leading to an increase in the total sound absorption coefficient. In addition, the study examined the structural makeup of a composite material resembling a sandwich panel. This composite material utilised luffa as the core material and was covered by a nonwoven flax surface skin made from waterborne polyurethane. An in-depth analysis was conducted to evaluate the impact of CNCs on the acoustic efficiency of this composite structure. The findings indicate that CNC-luffa composites have great potential for use in noise reduction systems.
The nano-engineered natural fibre composites provide numerous benefits such as their renewable sourcing, biodegradability, and the minimization of toxic by-products in production. It effectively addresses the increasing environmental and health concerns related to traditional acoustic materials.
To summarise, this study highlights both the natural sound absorption properties of luffa and the notable improvements made by integrating bio-based nano-reinforcements such as cellulose nanocrystals. The ramifications for the field of acoustic material research are significant, suggesting that luffa-based composites could replace commonly used synthetic absorbers, resulting in a new era of sustainable and health-conscious noise reduction technology.
The selection of acoustic materials is undergoing a significant change towards bio-based alternatives, mostly due to the negative environmental and health effects linked to synthetic options like polyurethane (PU) foam. This study explores the use of natural porous luffa as the sound absorption materials, with locally deposited cellulose nanocrystals (CNC) to achieve a hierarchical natural fibre composite. The effect of CNC loadings on acoustic properties have been systematically examined via impedance tube method based on ASTM C384 [4] and compared with the commercially available PU panels. The modification of luffa with 3 wt.% CNC resulted in a 13% increase in the average sound absorption coefficient across the 300 Hz to 2000 Hz frequency range compared to unmodified luffa. The absorption coefficients at low panel thickness ranges exhibit a significant enhancement compared to the unmodified luffa and PU foam. Due to their large surface area, CNCs can efficiently adhere to the cellular walls of the luffa structure. This adherence can potentially increase the density and complexity of the luffa's internal network. The proposed alterations to the micro-architecture are expected to enhance the reduction of sound wave interference and absorption in the material, thus leading to an increase in the total sound absorption coefficient. In addition, the study examined the structural makeup of a composite material resembling a sandwich panel. This composite material utilised luffa as the core material and was covered by a nonwoven flax surface skin made from waterborne polyurethane. An in-depth analysis was conducted to evaluate the impact of CNCs on the acoustic efficiency of this composite structure. The findings indicate that CNC-luffa composites have great potential for use in noise reduction systems.
The nano-engineered natural fibre composites provide numerous benefits such as their renewable sourcing, biodegradability, and the minimization of toxic by-products in production. It effectively addresses the increasing environmental and health concerns related to traditional acoustic materials.
To summarise, this study highlights both the natural sound absorption properties of luffa and the notable improvements made by integrating bio-based nano-reinforcements such as cellulose nanocrystals. The ramifications for the field of acoustic material research are significant, suggesting that luffa-based composites could replace commonly used synthetic absorbers, resulting in a new era of sustainable and health-conscious noise reduction technology.