SOUND DAMPING PROPERTIES OF PUR/NANO FABRIC SANDWITCH STRUCTURES

Abstract

Open cell polyurethane (PUR) foams (Gumotex, Břeclav, Czech Republic) of varying pore size distribution were tested for sound damping in the perpendicular incident sound wave geometry by means of Kundt´s tube measurements in the frequency range of 50-6400 Hz. Tested samples were modified by coating the top layer by nano non-woven fabric of PUR bases (SPUR, Zlin, Czech Republic) produced by means of Nanospider technology (ELMARCO, Liberec, Czech Republic) having varying air flow resistivity. Acoustic reactance of porous insulating materials is determined by layer thickness and in the lesser extent by surface density of the air permeable surface film coating. Acoustic resistance of the porous insulating material is determined by the air flow resistivity. This study allow to characterize the effect of the mutual influence of acoustic resistance and acoustic reactance components of the complex acoustic impedance on final sound damping characteristics of the studied sandwich like PUR based structures.