Abstract
Nonwovens are very important sound absorption materials used by the automotive and building industries. One of the most important fabric parameters that affect the sound insulation and absorption properties is the surface area. Higher surface area is often achieved by using low-diameter fibers in the insulation material. This research was done to prove that neither the thickness nor the weight of the material is as important as the total surface area of the fabric. Glass beads with 0.1mm, 0.5mm and 2.5mm sizes, which do not contribute considerably to the total surface area of the fabric, were imbedded into cross-lapped and needlepunched nonwoven structures. These beads were added in weight percentages of 25%, 50%, 75%, 100% and 200%. Sound insulation of glass bead imbedded nonwoven fabrics was tested using Clemson Boston Sound Insulation Tester. It was found that the micro-glass beads did not have a large impact on the sound insulation, as they do not contribute to the surface area of the nonwoven fabric. The samples with 0.1mm beads performed slightly better than samples with larger beads but not enough to make a significant difference. Since surface area is the major parameter that affects sound insulation, simply increasing the weight does not affect the sound insulation property of the material.