Investigation of the factors effecting acoustic properties of nonwoven fabrics produced with different methods

In this thesis work, it is aimed to investigate the properties of SMS type multilayer nonwovens for sound insulation as an alternative product to commercially used materials with the production and short production line advantages. For this purpose; flat and point calendered, in round and trilobal fiber cross-sectional shapes of homocomponent and bicomponent structures produced from polyester and polypropylene fibers, totally 49 multilayer nonwoven samples with 7 different fabric weights were obtained. In order to evaluate the sound insulation performance of these samples, mechanical performance characteristics such as air permeability, sound absorption coefficient and pore size measurements as well as bursting strength resistance and breaking strength were determined with standart test procedures. All test results obtained from the tests were analyzed statistically by using Design Expert 9 package program. As the result, the sound absorption properties were improved by bicomponent fibers in spunmelt nonwovens, and it had a high correlation with air permeabilty and pore sizes. For high frequency ranges, sound absorbing performance of nonwovens became better with the increase of fabric weight per unit area, decrease of air flow resistance and pore sizes. It was effected by the fiber cross-sectional shape and the fiber type of homocomponent or bicomponent type. Key Words: Nonwovens, Spunbond, Meltblown, Bicomponent Fibers, Sound Absorption, Permeability