Submitted to: American Association of Textile Chemists and Colorists Abstracts
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2005
Publication Date: 1/15/2006
Citation: Parikh, D.V., Sachinvala, N.D., Chen, Y., Sun, L., Bhat, G., Ramkumar, S. 2006. Acoustic Properties of Enviromentally Benign Automotive Natural Fiber Composities. American Association of Textile Chemists and Colorists Abstracts. 6(1):43-48. Interpretive Summary: The problem of adequately shielding automobile passengers from engine noise and random outside noise is high on the priority list for automobile manufacturers. The ability to reduce the amount of noise entering the passenger compartment of automobiles offers a competitive advantage to manufacturers. The study attempts to develop and quantify the sound absorbing properties of a number of more efficient natural fiber-based noise absorbing materials made with natural fibers kenaf,jute,flax and cotton in blends with polypropylene. The testing results demonstrate that each of the cellulose-based nonwovens composites have greatly improved sound absorbing properties that are comparable to the materials currently used in automobile interiors. Although there is increased efficiency in noise reduction with these materials, the individual acoustic characteristics of various vehicles determine the type and amount of material required. Use of these natural materials will provide automobile passengers with a more quiet, safer environment (relatively biodegradable interiors) at a reduced cost compared to materials currently in use in the industry. Additionally, the weight of the vehicle (kenaf's fiber density is 1.40 vs. 2.55 for glass) is reduced. Hence, greater gas mileage for the vehicle is attainable.
Technical Abstract: Natural fiber composites have excellent appearance as well as environmental benefits, and are lighter than synthetics because of the lower fiber densities of the natural fibers. The objective of this research was to determine the acoustic properties of potential floor coverings used either alone or in combination with cotton nonwoven underpads. Using various weight ratios of natural fiber to synthetic fibers (a) air-laid needlepunched, and (b) carded needlepunched, moldable composites were produced from kenaf, jute, waste cotton, and flax with recycled polyester and off-quality polypropylene. The standard test method ASTME E 1050 (A Bruel & Kjaer meter, employing two microphones, impedance measurement) was used to determine acoustical properties of the composites. The measurements demonstrated that each of the natural fiber-based nonwoven floor covering composites contributed to noise reduction because of their absorptive properties. The efficiency of the absorption properties was greatly enhanced with the use of soft porous cotton underpads.