Determination of mechanical and damping properties of hazelnut shell powder reinforced biocomposites by ultrasonic method.

This research was carried out to figure out the effect of chemical treatments of hazelnut shell powders (HSPs) on the elastic properties, ultrasonic wave velocities, and damping properties of bio‐based epoxy resin (BER) biocomposites. Natural hazelnut shells (HSs) were chemically treated using sodium hydroxide (NaOH), and acetic anhydride (AA). Then, HSs that were chemically treated with NaOH and AA, and HSs that were not subjected to chemical treatment were ground to obtain HSPs. The treated HSPs (HSP‐NaOH and HSP‐AA), and untreated HSPs were contributed to the neat BER in varied compositions such as 10–50 wt% to obtain the BER/HSP, BER/HSP‐NaOH, and BER/HSP‐AA biocomposites. The effect of untreated, and treated HSP ratios on the density, ultrasonic wave velocities, Young's modulus, Bulk modulus, Shear modulus, Poisson ratio, microhardness, and damping characteristics (attenuation coefficient, loss tangent and quality factor) of the novel HSP‐based biocomposites, was investigated by the ultrasonic pulse‐echo overlap method (PEOM). A significant increase in the density, ultrasonic wave velocities, and elastic modulus values of the biocomposites was seen compared to the neat BER. Based on the obtained elastic modulus values, the most appropriate combination ratio between the neat BER, and HSP‐NaOH was determined as 50:50. [ABSTRACT FROM AUTHOR]