| 초록 |
In recent years, the polyurethane foams are generally used for sound absorption materials in automobile industry. In free-rising polyurethane foams, the different cell morphology are obtained by the sample locations and flow directions. The designing morphological and physical properties for increasing the sound absorption coefficient is important. For obtaining the relationship between sound absorption coefficient and flow direction of polyurethane foams, scanning electron microscopy (SEM) and impedance tube were used. Also, the physical property of free-rising polyurethane foams was explored by using dynamic mechanical analyze (DMA). From these result, the sound absorption coefficient and physical properties are strongly affected by flow direction and sample location, and these inconstant sound absorption coefficient can be modulated by increasing gelling reactivity. |
