Investigating the Acoustic Behavior of Polyurethane Foam Reinforced with Clay Nanoparticles

Introduction: Disturbing noise can cause physical and mental illnesses among workers; for this reason, it is necessary to restrain it, especially in workplaces. Using sound-absorbing materials with suitable acoustic properties has been a growing trend in mitigating noise. This study aimed to improve the acoustic properties of polyurethane foam (PUF) as a sound absorber. Material and Methods: In the present study, PUF was synthesized with different percentages of clay nanoparticles (0 -1.2 wt.%), and then the Sound Absorption Coefficient (SAC) of the synthesized PUF was measured by the acoustic impedance tube in the frequency range of 63 to 6400 Hz according to the ISIRI 9803 standard without an air gap behind the sample. The morphology of the foam was also investigated by Scanning Electron Microscope (SEM). Results: The results showed that the addition of clay nanoparticles to PUF improved the sound absorption behavior of the samples, and the best sound absorption behavior was for PUF with 1.2% weight of nanoparticles at low frequencies (500-2600 Hz). This increase in the absorption coefficient can be due to the increase in the number and smaller size of the pores with the increase in the amount of nanoparticles in PUF. Conclusion: This study illustrates that the incorporation of clay nanoparticles into PUF at varying percentages results in an enhanced absorption coefficient. The presence of clay nanoparticles leads to a reduction in cell size and an increase in the number of pores, consequently enhancing surface friction. The absorption coefficient was observed to increase with the growing concentration of clay nanoparticles in PUF