Search

This study introduces a novel approach using wood fiber/PLA composite microperforated panel (WFCMPP) for indoor sound absorption purposes. WFCMPP, comprising rubber tree chip-derived fibers and a polylactic acid (PLA) matrix, with the dimensions of the rubber tree chip-derived fibers ranging from 0.5 to 1 mm, demonstrated promising sound absorption coefficients comparable to other natural fiber composite microperforated panels. The maximum sound absorption coefficient was recorded at 0.989 with a resonance frequency of 1416 Hz when the wood fiber composition was 30 %. The study also investigates the impact of wood fiber composition on sound absorption, revealing a linear relationship between fiber content and both porosity and sound absorption. The peak sound absorption coefficient of WFCMPP remained almost identical at different air gap thicknesses, showcasing the versatility and effectiveness of the samples. Additionally, the performance remained robust even with variations in air gap size. Scanning electron microscope analysis confirms the irregular porous structure and complexity contributing to enhanced sound absorption. WFCMPP presents a sustainable and effective alternative for acoustic applications, combining sound absorption performance with environmental considerations. [Display omitted] • Microperforated panels (MPPs) were fabricated from wood fiber/PLA composite using conventional machining. • Sound absorption of wood fiber/PLA MPPs (WFCMPP) was measured using an impedance tube. • All samples showed excellent absorption, with coefficients exceeding 0.9 between 1,400 and 1,470 Hz. • Porosity and surface morphology analyses were conducted to verify the complex structure of WFCMPP. • WFCMPP's sound absorption performance was comparable to other natural fiber-based MPPs. [ABSTRACT FROM AUTHOR]

Oil palm mesocarp fibre is seen as one potential of reinforcement in polymers due to its high strength, low cost, environmentally friendly nature and availability. Recently, it has attracted greater interest from academia and industries due to its potential for making a low-cost sound absorption panel. Therefore, this study is obliged to investigate the acoustic characteristics and the physical properties of oil palm mesocarp fibre (OPMF) as a porous material for sound absorbing panel. The measurements of the sound absorption coefficient are determined by using: (1) analytical model of Delany-Bazley, (2) analytical model of Johnson-Champoux-Allard, and (3) experiment of the impedance tube method. A commercial polyurethane (PU) was used as a composite binder during the intermixing process with the fibres. The manufacturing parameters are 10/90, 20/80, 30/70 and 40/60 by wt.% of PU/OPMF. The outcome shows that adding binder compacts the fibre by reducing the pore diameter and porosity, thus increasing the flow resistivity. Results also indicate that Johnson-Champoux-Allard model can justify the overall trend of absorption of the coefficient perfectly in contrast to the Delany-Bazley model. Overall, OPMF with 10 wt.% PU binder displayed greater absorption from low to mid-frequency range and the highest value of noise reduction coefficient of 0.66, while fibres with 20 wt.% PU produced the highest value of sound absorption coefficient of 0.99 at 1000 Hz. The results conclude that oil palm mesocarp displays a potential and brighter prospect to be implemented as a sound absorption panel as demonstrated in this study. [ABSTRACT FROM AUTHOR]

This paper investigates the sound absorption of biodegradable composite micro-perforated panel (BC-MPP) made from kenaf fibre and biodegradable polymer known as polylactic acid (PLA). BC-MPP samples were made through conventional machining method such as mixing, drilling, and hot pressing process. Sound absorption of BC-MPP samples were measured by using impedance tube. The porosity and tensile strength of BC-MPP samples were determined by using porosity tester and universal testing machine respectively. The effects of material composition and air gap thickness behind the panel towards the sound absorption coefficient of BC-MPP samples along with the porosity and tensile strength of BC-MPP samples will be presented in this paper. Results indicate that the sound absorption coefficient of BC-MPP samples could be affected by the difference of composition percentage of kenaf fibre and PLA. The porosity of BC-MPP sample increases along with the increment of kenaf fibre composition. However, the increment of kenaf fibre composition causes the reduction of tensile strength of BC-MPP sample. As the air gap thickness behind the panel increases, the peak absorption of BC-MPP sample shifts nearer to lower frequency range. The maximum sound absorption coefficient of BC-MPP sample can be varied as well by altering the air gap thickness behind the panel. [ABSTRACT FROM AUTHOR]