Acoustic, ultrasonic, mechanical properties and biodegradability of sawdust/ recycled expanded polystyrene eco-friendly composites
A. Abdel‐Hakim, Tarek M. El-Basheer, A. M. El‐Aziz, M. Afifi
Abstract
In the present study, sawdust/recycled expanded polystyrene (SD/rEPS) composite was manufactured to be used as sound-absorbing materials. To achieve this aim, SD/rEPS composites containing different loading level (0, 20, 40, 60 and 80 wt percent) of SD were prepared. The addition of 20% SD exhibited better dispersion within recycled expanded polystyrene (rEPS) matrix than higher loading level of SD, as indicated from scanning electron microscope. Consequently, the tensile strength and flexural strength were improved by 16.7% and 14.1%, respectively. The higher loading level of SD displayed aggregation within rEPS matrix which reflected negatively on the mechanical properties. Young's and shear modulus varied from between 0.41 and 1.23 GPa for 0–60% SD. Longitudinal and bulk modulus recorded a reduction from 0.55 to 1.26 GPa with increasing SD. Sound absorption improved with increasing SD loading level. Nonperforated samples of 60% SD and 80% SD had high absorption at 500 and 315 Hz where the sound absorption coefficient (SAC) was about 0.85 and 0.75, respectively. The perforated sample of 80% SD exhibited the highest sound absorbing at low frequencies 315 Hz (SAC~0.9). The biodegradability of the prepared composites was investigated using burial in soil for 90 days where the weight loss increased linearly with increasing SD within the rEPS matrix.