Effect of graphene on the sound damping properties of flexible polyurethane foams

The sound absorption coefficient, airflow resistivity and cell size of polyurethane (PU) foam with graphene as a solid-type additive and tetramethylsilane (TEMS) as a liquid-type additive were investigated. The results show that the sound absorption coefficient and airflow resistivity are closely related, and that increase of the flow resistivity improves the sound absorption coefficient of the PU foam. For the PU foam/graphene (0.2 phr) composite, the values of the sound absorption coefficient and airflow resistivity were 0.52 (frequency range of 1600 to 2500 Hz) and 292,900 Ns/m4, respectively, which were the highest values among the investigated additive species and additive content. The sound absorption coefficient of the PU foam/graphene (0.2 phr) composite increased by 18.2% compared with that of the PU foam without graphene. The results of the sound absorption coefficient and airflow resistivity of the PU foam suggest that graphene is an effective additive in the formation of the PU foam to decrease the cell size and increase the tortuous paths of the foams, and this small cell size consequently increases the acoustic damping properties of the PU foam.