The potential of napier grass leaf fibres as an acoustic absorber

Abstract

Acoustic absorbers are introduced to treat poor acoustic enviroment in rooms. However, many available acoustic absorbers in the market are composed of hazardous materials. Therefore, there are demands for the use of sustainable materials in the production of acoustic absorbers. This research investigated the sound absorption potential of grass leaf fibres, i.e. Napier grass, as material for acoustic absorbers. Various bound Napier grass fibre samples, with and without binder under normal press with different thickness, were prepared and tested by using an impedance tube test for sound absorption coefficient (SAC) determination. Samples with binder under hot press with thickness of 10mm were also prepared. The results revealed that 5mm and 20mm fibres, respectively, when bonded with urea formaldhyde (UF) under normal press and with thickness of 30mm, produced a relatively high SAC for frequencies at 500 Hz, 1000 Hz and 2500 Hz, and thus resulted in a high average NRC value of 0.59. This exceeded the value for synthetic fibre-glass and was similar to rockwool. Moreover, the sound absorption performance of 20 mm fibre size hot pressed samples were better than hot pressed 5mm fibre size at 500 Hz frequency until 1000 Hz, as well as the bulk and fibre bonded with UF samples for all frequencies. This study concluded that non-toxic Napier grass fibres can be used in the production of sustainable acoustic absorbers.