Effect of the Expandable Polystyrene on Acoustic Property of the Polyurethane Composite Foams

Polyurethane (PU) foams are used as a sound absorbing and cushioning materials in the automotive industry. In this study, expandable polystyrene (EPS) was used as a filler and the effect of EPS in PU foams on the acoustic property was investigated by varying its contents. Even if the content of EPS increased, there was little change in the internal morphology of PU foams, because the EPS could not cause the deformation of the inner wall. However, as the EPS content increased, the low-frequency sound absorption performance increased, because the EPS acted as an obstacle to increase the path of sound waves. Finally, to confirm the effect of EPS, EPS was removed using toluene. After removal, the sound absorption performance showed a lower than that of PU foam with an EPS content of 0 wt%. EPS plays a role in improving the sound absorption performance inside the PU foam.