Fabrication of polyurethane composite foams with magnesium hydroxide filler for improved sound absorption

In automobile industry, sound absorption material has huge importance because of noise, vibration, harshness (NVH) control. Polyurethane foam is commonly used as a sound absorption material because of its high sound absorption efficiency. In this study, magnesium hydroxide filler is used in fabricating polyurethane composite foams for improving acoustic property. Use of the filler improves the sound absorption efficiency not only with enhancing damping motion by the fillers but also with increasing the number of partially opened pores. Noise reduction coefficient was improved about 70% at the optimum open porosity of 0.63 compared with the non-filler case. Fine cell morphology with well-developed cavity and pore structures is advantageous in obtaining high sound absorption efficiency. The optimum open porosity is achieved at the filler content of 1.0 wt% for the highest noise reduction coefficient.