On the sound absorption improvement of water hyacinth and coconut husk based fiber reinforced polymer panel

Abstract

This paper emphasizes on the sound absorption improvement of the water hyacinth and coconut husk based fiber reinforced polymer (FRP) panel. The dry water hyacinth and coconut husk were milled and sieved before it mixed with polyester and methyl ethyl ketone peroxide as the catalyst. The composition is 200 ml, 25 grams, and 20 ml for the polyester, fiber, and catalyst respectively. The mixture casting is by using a square tray to form a flat FRP panel through open air drying without any compaction process. Three different approaches i.e. multiple quarter wavelength resonators, air cavity, and front fibrous layer inclusion are implemented to the FRP to improve its sound absorption performance. The entire measurements conducted by using transfer function based impedance tube technique refer to ASTM E-1050-98 standard. B&K 4206. It found that the proposed approaches are increase sound absorption coefficient of the bulk FRP significantly. The best performance occurred on the coconut husk based FRP when the 8 of quarter wavelength resonators combined with the fibrous layer. Sound absorption increased accordingly to above of 0.7 starting from 1.5 kHz. On the other side, the air cavity shows similar influence on the entire test sample due to Helmholtz resonance mechanism.