Acoustic absorption coefficient of open-cell polyolefin-based foams

The acoustic absorption of open-cell polyolefin (PO) foams with densities between 23 and 64 kg/m3 has been measured and compared with that of open-cell polyurethane (PU) foams. Acoustic parameters related to the cellular structure, such as porosity, tortuosity and airflow resistivity, were also measured. PO foams show higher tortuosity and airflow resistivity than the PU open-cell foam; as a consequence, they show a higher absorption coefficient than PU open-cell foam in the frequency range between 1000 and 2000 Hz. We also modeled the acoustic behavior using the Biot–Allard theory with the Johnson approach, fitted using a genetic algorithm. The fits of the acoustic absorption coefficient as a function of frequency were reasonably consistent with the experimental results.