The influence of alkaline treatment on acoustical, morphological, tensile and thermal properties of Kenaf natural fibers

Among fibers with lignocellulosic origin, Kenaf fiber, because of its advantages and as a sustainable alternative to synthetic fibers has received increasing attention for manufacturing hybrid composites with reasonable acoustical and physical properties. The present study deals with the impact of chemical treatment of Kenaf fibers on the overall properties of hybrid composites fabricated from these fibers. Also, the results from predictive analytical model of sound absorption for these composites were employed for comparison with the experimental findings. Kenaf fibers were treated at room temperature with 6% concentration of sodium hydroxide (NaOH) and 4 h immersion time. Having manufactured the composites with the treated and untreated fibers, the normal sound absorption coefficients and tensile strength properties of these sample composites were determined according to ISO 10534-2 and ASTM C1557 − 14, respectively. The SEM analysis of the treated and untreated fibers revealed that in terms of fiber diameter and morphology the former was thinner and had better surface appearance. The experimental measurement of acoustic absorption coefficients of the composites made of treated fibers demonstrated superior sound absorption properties and tensile strength. The revised empirical models proposed by Delany & Bazley and Garai & Pompoli along with Nelder-Mead simplex method were employed and well predicted the sound absorption coefficients of the sample composites. There was also a fair consistency between the experimental and predicted results.