PERFORMANCE OF WOOD COMPOSITES WITH NATURAL FIBER AS SOUND ABSORBER OF BUILDING MATERIALS

Natural fibers are an alternative to reduce the use of synthetic materials in acoustic products. Such fibers have the benefits of being inexpensive, environmentally benign, biodegradable, and safe for human health. The influence on sound absorption coefficient of different natural fibers including rubberwood, coconut coir, and oil palm empty fruit bunches was investigated. The samples were composed of three kinds of natural fibers, three different fiber sizes, and two different kinds of adhesives. The porosity values of the samples were found in the range of 4.58-8.84% whereas the lowest water absorption value was found on the sample with rubberwood fiber in the range of 57.62-127.83%. Impedance tube testing was used for the sound absorption tests following ISO 10534-2. The experimental result revealed that the natural fibers have good performance associated with the fiber length. The longer fiber performs the better sound absorption than that of the short fiber.  All kinds of natural fiber plates tested had sound absorption of 50% above 3.5 kHz whereas the oil palm fiber gave the highest absorption coefficient at 95%. The fiber size fraction approved that those fibers could improve the peak values of sound absorption. The small fiber size gave higher peak values than that of the large fiber size. The type of adhesive influences sound absorption coefficient on the sample with small fiber size (80 mesh) than that of the large fiber size (40 mesh). The output of this study reveals the waste plant fibers could adopt to develop sound absorber building materials.