1. ANALYSIS OF MIXED COMPOSITION OF COCONUT
AND KENAF FIBERS EFFECT AS RAW OF COMPOSITE
MATERIALS TO THE SOUND ABSOPRTION COEFFICIENT
ABSTRACT
The fabrication of sound absorbent material using natural
fiber is an alternative to minimize the noise level of sound in certain
place. Indonesia has a great potential of natural fiber, such as
coconut and kenaf fibers. The objective of this research is to observe
the influence of composition the mixture coconut and kenaf fibers as
raw composite with polyester matrix on sound absorption coefficient,
and to know the frequency region which produces high sound
absorption coefficient. In this research, we used hand lay-up process
and tested using a series of sound absorption test. The composition
variation of coconut fibers compared kenaf fibers are 0:4, 1:3, 2:2,
3:1, and 4:0, the coconut fibers and kenaf fibers sifted by 40 mesh or
equivalent to 420 µm. The results showed that the increasing of
coconut fibers composition then the higher absorption coefficient
value. Sample with the composition of 4:0 has the highest absorption
coefficient of 0,67. The higher density sample show the lowest sound
absorption coefficient, on 0.82 g/cm³ of density show that the sound
absorption coefficient is 0.47. The sample had the highest the
absorption coefficient with the frequency of 1000 Hz.
Keywords: coconut fibers, kenaf fibers, polyester, density, frequency,
sound absorption coefficient.