Performance evaluation of bamboo charcoal-filled natural fiber composites for sustainable structural and acoustic applications

Abstract

This study provides a comprehensive analysis of the thermal, mechanical and acoustic properties of natural fiber composites with bamboo charcoal and blends of sugarcane bagasse (SCB) and rice husk (RH) at various weight ratios. Hand lay-up was used with pre-treated fibers and a well-formulated epoxy-hardener matrix to facilitate superior bond strength between fibers and matrix. Based on Lee’s Disk Method for analyzing thermal conductivity, it was observed that the S₀R₇₀B₃₀ formulation (70% RH + 30% bamboo charcoal) had the lowest conductivity of 0.04043 W/m·K. On the other hand, the composite containing 70% SCB and 30% bamboo charcoal had the highest thermal conductivity of 0.06609 W/m·K, indicating a reduction in the level of insulation as the SCB content increases. According to ASTM D3039 and D790 specifications, the S₇₀R₀B₃₀ sample showed the highest tensile strength at 630 N due to improved interfacial. Scanning Electron Microscopy (SEM) revealed well dispersed fibers and reduced microvoids in the hybrid materials, confirming the reported mechanical results. Sound absorption measurement was performed using an impedance tube, as prescribed by ASTM E1050 and ISO 10534-2, over the frequency range from 125 to 6300 Hz. In the sample that only contained bamboo charcoal (S₀R₀B₁₀₀), the maximum Noise Reduction Coefficient (NRC) was obtained, equal to 0.42, due to the mesoporous structure and high internal surface area, while the hybrid S₅₀R₀B₅₀ sample. These results show an optimized blend of bamboo charcoal with SCB or RH can be tuned to customize composite performance for various functional applications. The results corroborate the appropriateness of bio-based composites for thermal insulation, mechanical strength, and acoustic absorption requirements in construction, transportation, and noise control systems.