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Investigation of Thermal Conductivity and Sound Absorption Properties of Rice Straw Fiber/Polylactic Acid Biocomposite Material

ABSTRACT In the last decade, there has been an increasing trend in the use of agricultural wastes as reinforcements for high value-added composite materials as an ecological approach. In our previous study, a nonwoven fabric was produced from rice straw fibers. In this study, the previously obtained nonwoven reinforcement material and the polylactic acid (PLA) in granule form are used in the hot press process to produce new single- and double-layered biocomposite materials. The characterization of the obtained composite materials is made using Scanning Electron Microscope (SEM), Fourier-Transform Infra-red Spectroscopy (FTIR), and Differential Scanning Calorimetry (DSC) instrumental methods. The thermal conductivity and sound absorption properties of the materials are also investigated. The double-layer composite material has the highest sound absorption coefficient value, which is almost 0.99 while the single-layer material’s is around 0.34. According to the thermal conductivity measurement results, the thermal conductivity of the single-layer composite material is 0.02564 W/m.K and that of the nonwoven material produced with rice straw which is 0.01618 W/m.K. The thermal conductivity of the single-layer composite material is approximately 50% higher than that of the nonwoven material. The single-layer composite material can be preferred in industrial insulation applications since the material with a low thermal conductivity coefficient is the best choice for thermal insulation purposes.