Effect of Fiber Diameter and Air Gap on Acoustic Performance of Nanofibrous Membrane

The absorption of sound in the low frequency range is problematic with fibrous materials made up of coarser fibers. In that case, highly efficient sound absorption materials from much finer fibers must be developed. Although studies on the acoustic properties of conventional textile materials started in the nineties, analysis of the acoustic properties of the electrospun nanofibrous membranes is a novel subject. Nanofibrous membranes can improve acoustic insulation products by increasing the sound absorption coefficient, reducing material thickness, and decreasing material weight offering a competitive advantage. The purpose of this study is to analyze the effect of fiber diameter on the acoustic behavior of nanofibrous membranes. coefficient of thin PVA nanofibrous membranes and foil was compared with each other. The result of the experimental study showed that the shapes of frequency functions are analogical for thin polymeric foil as well as for nanofiber PVA membrane. Furthermore, as the time of water vapour action to PVA nanofibers layer is increased, the number of local place with different mass increased and merged fibers should increase too which resulted in an increase in the absorbed frequency range. In another study on the comparison of sound absorption behavior of nanofibrous layer and polyethylene foil with the same area weight, she found that nanofibrous layer had higher sound absorption coefficient than foil. Moreover, an increase in the area weight and size of air gap between the membrane and rigid wall provided an increase in the sound absorption coefficient (5). There are also other reports (6-8) on the acoustic properties of nanofibrous membranes. Sound absorbents based on nanofibers can have a higher absorption factor compared to traditional absorbents especially in lower frequencies. The aim of this study was to discuss the sound absorption and transmission loss performance of nanofibrous resonant membranes