The usage of natural materials for the green acoustic panels based on the coconut fibers and the citric acid solutions

Acoustic panels of sound absorbers are used to overcome noise in an environment. Expensive panels using fabricated materials, which contains a lot of chemicals are mostly used in practice for noise reduction. Natural fibers have been extensively used to produce environmentally friendly composite materials and therefore, known as green materials. Coconut fibers hold great potential for substituting the expensive synthetic fibers in manufacturing acoustic absorption boards. This study aims to determine the acoustical performance of a green particleboard made from coconut fiber and citric acid solution. The acoustical performance is represented by sound absorption coefficient. The sound absorption coefficient of these panels were tested based on ASTM E-1050-98 standard using B&K impedance tube. The small test samples were tested in the frequency range of 50 Hz to 6,400 Hz. The results show that the tested panels are insufficient in absorbing sound of low frequencies. The panels absorption ability is improving in the range of 1,000 to 6,400 Hz. Furthermore, a morphological analysis has been done by using Phenom Pro X Scanning Electron Microscope to observe the effectiveness of citric acid solution in gluing the fiber. The variations of citric acid solution are 20%, 10% and 5%. It is shown that the lowest concentration has more pores distribution.