Effect of Nanoparticles on Acoustics Properties of Polyurethane Foam

Nowadays, with the increase of population growth and development of industry, noise pollution is increasing, which has been the source of many social and urban anomalies. In addition, noise pollution causes exhaustion and decreased efficiency of workers in the workplace. Sound is a mechanical wave that requires an environment to transmit. Polymers minimize and remove wave energy due to their viscoelastic properties, especially in viscous regions. This is done through the viscous loss and the sound is absorbed. The literature review shows that the addition of nanoparticles improves the properties of polyurethane foams, especially their acoustic properties. These nanoparticles increase the sound propagation paths through the polymer sample and increase the probability of sound wave attenuation through viscous loss. Depending on the aspect ratio, nanoparticles are divided into various forms including plate-like nanoparticles such as graphene and graphene oxide, nanotubes containing carbon nanotubes and particulate nanoparticles containing metal oxides such as zinc oxide and nanoclays that examined by many researchers to study the effect of each of these nanoparticles on sound absorption in polyurethane foam samples. In this article, first the sound and its properties, then polyurethane as one of the most important members of the polymer family are discussed. Also, among the various forms of polyurethane, polyurethane foams is reviewed.