Development of Natural Fiber Nonwovens for Application as Car Interiors for Noise Control

As natural fibers are noise-absorbing materials, renewable and biodegradable nonwovens have been developed using natural fibers such as banana, bamboo, and jute fibers for the automotive interiors to reduce noise, which currently contain traditional materials such as glass and other manufactured fibers and foams that are difficult to recycle. Three types of nonwovens were developed using needle-punching technique by blending bamboo, banana, and jute fibers with polypropylene staple fibers in the ratio of 50 : 50. Sound absorption coefficient was tested by impedance tube method (ASTM E 1050). Comparison of physical properties such as areal density, thickness, stiffness, tensile strength, elongation, structural properties, and comfort properties such as air permeability and thermal conductivity were performed for all samples. It is observed that the bamboo/polypropylene nonwoven with its compact structure showed, higher tensile strength, higher stiffness, lower elongation, lower thermal conductivity, lower air permeability, and good absorption coefficient than others and it is suitable for the automotive interior noise control. At 800 Hz, the absorption coefficient of bamboo/polypropylene and jute/ polypropylene is equivalent to the target level but it is lower by 22% in banana/ polypropylene. But at higher frequencies (1600 Hz), there is a reduction from the target level in all the nonwovens, which could be improved by increasing the thickness of the nonwovens.