Multi-fiber needle-punched nonwoven composites: Effects of heat treatment on sound absorption performance

Abstract

Nonwovens have been increasingly used in car interiors for noise reduction. Most of these nonwovens are subjected to thermal treatments to give the nonwovens their final three-dimensional forms. Therefore, it became crucial to investigate the effects of thermal treatment on sound absorption characteristics of nonwovens. In this study, the effects of the material and treatment parameters on airflow resistivity and normalincidence sound absorption coefficient of thermally treated three-layered nonwoven composites have been studied. The material parameters included fiber size and porosity. The treatment factors included the temperature and duration. The thermally treated three-layered nonwoven composites are classified into three types based on the material content and fiber blend. Sandwich structures consisting of polylactide/hemp/polylactide and polypropylene/glassfiber/polypropylene layers were called LHL and PGP, respectively. The sample which consisted of three layers of an intimate blend of polypropylene-glassfiber was named as PGI. Both temperature and duration of thermal treatment have been found to affect air flow resistivity and sound absorption. An increase in air flow resistivity and a decrease in sound absorption have been detected with heat treatment. A similarity has been observed between the thermal behaviors of PGP and PGI, which included the same thermoplastic polymer fiber. Variation in air flow resistivity of sandwich structure nonwoven composites increased with the increase in temperature, which was not observed in the intimate blend ones. The air flow resistivity of heat-treated nonwovens followed a steeper trend compared to unheated nonwovens per change in material parameters. In terms of treatment parameters, the difference

Study on Sound Absorption Performance and Transmission Behavior of Perpendicular-laid Nonwovens

“…For hollow fibers, as only the pores that carry air flow in connection with the ambient air are of interest in terms of sound absorption, the voids in hollow fibers are not included in the porosity [17,18,19]. …”

Sound absorption properties of bilayered nonwoven composites

“…Composites prepared by mixing short ramie fiber reinforced poly(Llactic acid) composites and flame retardant ammonium polyphosphate and plasticizer poly(butylene adipate-coterephthalate) added ramie fabric/poly(L-lactic acid) composites provided better sound absorption properties [26]. Sandwich structures consisting of polylactide/hemp/polylactide and polypropylene/glass-fiber/polypropylene improved sound absorption rates in the mid to high frequency ranges [27]. Single-fiber and multi-fiber type three-layered and needle punched nonwoven composites made from poly(lactic acid) (PLA), polypropylene (PP), glassfiber, and hemp fibers improved air flow resistance [28] and sound absorption [29] properties.…”

Abrasive Wear Behaviour of Surface Modified Jute Fiber Reinforced Epoxy Composites

“…7 These days increasing the interest of natural fiber polymer composites are being chosen over the synthetic based fiber composites due to the several advantages such as easy availability, low density, low cost, biodegradability, a range of mechanical properties and less abrasiveness. [8][9][10][11][12] From various natural fibers, jute appears to be a promising fiber because of its high aspect ratio and toughness in comparison to other natural fibers. Generally, natural fibers are not problem free alternatives and their structural compositions like cellulose, hemicelluloses, lignin, pectin and waxy elements which allow moisture absorption from the environment which leads to poor bonding with the matrix materials.…”