Improved acoustic damping in polyurethane foams by the inclusion of silicon dioxide nanoparticles

Abstract

AbstractIn this research, flexible semi‐open cell polyurethane (PU) foams incorporating silicon dioxide (SiO2) nanoparticles are produced to have improved acoustic damping. Nanoparticles of different loading fractions and various sizes are employed to achieve improvement in sound absorption of foams. The effect of SiO2 nanoparticles’ size on the acoustic damping of PU foams, which is investigated in this study, has not been studied before. The mechanical, nonacoustical, and acoustical properties of the foams are measured by experiments or calculated by theoretical models. The results show that a PU foam sample incorporating only 0.05 wt% of nanoparticles has a great improvement (more than 90%) in sound absorption ability over the frequency range of 500–1,000 Hz. By the increase in the loading fraction of nanoparticles, a gradual decrease in acoustic damping is observed. Moreover, regarding size of nanoparticles, those with bigger nanometer sizes bring about a better sound absorption ability in PU foams. Besides acoustical properties, microcellular characteristics, nonacoustic parameters, and mechanical properties are also presented which are in agreement with the improved acoustical ability of foams quite well.