Sound Absorption Characteristics of Nanofibre Web Coated Foams

Sound absorption properties of polyamide 6 (PA6) nanofibre webs and a widely used sound absorption foam coated with nanofibre webs have been investigated. Initial studies have focused on the electrospinning by using PA6 polymer to obtain uniform and bead-free nanofibres. Thereafter, nanofibres are electrospun on an absorption foam through two spinning durations of 10 h and 20 h. Thicknesses, mass per unit area values, porosities, pore sizes, and Brunauer-Emmet-Teller surface areas of the webs are determined. At characterization stage, sound absorption coefficients of pure nanofibre webs, pure foam, and foams enhanced with nanofibre webs are measured by acoustic impedance tube method. Noise reduction coefficients (NRC) are also calculated. Sound absorption coefficients at 6400 Hz are observed as 0.76 and 0.74 for nanofibre webs electrospun during 10 h and 20 h respectively. The NRC values are found as 0.189, 0.197 and 0.192 for pure foam sample and nanofibre webs electrospun during 10 h and 20 h respectively. Overall results of the study indicate that moderate mid-high frequency sound absorption and noise reduction coefficients are obtained by using the nanofibre web coated foams.