Development of Sustainable Lightweight Acoustic Composites from Denim, Flax, and Hemp Fibers

The textile and clothing industries pose a serious problem in terms of environmental sustainability as they are among the sectors that produce the most waste worldwide. In this context, recycling both pre-consumer and post-consumer clothing waste into composite materials is of great importance in terms of both waste management and material science. In this study, composite panels were developed using waste denim fabrics in different natural fiber compositions, recycled flax fibers derived from waste linen fabrics, and virgin hemp fibers as reinforcement materials. Polypropylene/polyethylene nonwoven interlining waste served as the matrix material, and panels were fabricated by hot pressing at two different reinforcement/matrix ratios. Acoustic properties were evaluated through sound absorption coefficient (SAC), noise reduction coefficient (NRC), and sound transmission loss (STL) measurements. In the case of denim waste, the results showed that flax or hemp blended samples provided better sound absorption than 100% cotton, especially at low matrix ratio. For the rest, while pure flax samples absorbed sound well, pure hemp samples showed good barrier properties with high transmission loss.