Investigation of sound transmission loss of natural fiber/rubber crumbs composite panels

Natural fibers and their waste are widely used all over the world, and their production has been increasing continuously. But, the rubber crumbs from used tire disposal are nonbiodegradable and present significant problems about their end-of-life given a critical environmental impact. These problems require recycling policies to provide the collection and recycling of used clothing, textile wastes, and rubber crumbs. In this work, the acoustic properties of insulator panels from the combination of textile fibers and rubber crumbs material were analyzed. Insulator panels demonstrated a good sound transmission loss (STL) characteristic, especially at high frequencies. The STL of the manufactured panels from a combination of fiber (cotton, wool, and Kapok) and rubber crumbs was investigated at the different sound frequencies. Results indicated that the fiber/rubber crumbs panel had a significant STL profile of 47 dB, 40 dB, and 35 dB, for Kapok, wool, and cotton, respectively. The addition of polylactic acid meltblown nonwoven fabric on the surface of the rubber crumbs side considerably increases the STL by 20%.