Abstract: Today, the pollution due to non-degradable material
such as plastics, has led to studies about the development of
environmental-friendly material. Because of biodegradability
obtained from natural sources, polylactid acid (PLA) and ijuk fiber
are interesting to modify into a composite. This material is also
expected to reduce the impact of environmental pollution. Surface
modification of ijuk fiber through alkalinization with 0.25 M NaOH
solution for 30 minutes was aimed to enhance its compatibility to
PLA, in order to improve properties of the composite such as the
mechanical properties. Alkalinization of the ijuk fibers annihilates
some surface components such as lignin, wax and hemicelloluse, so
the pore on the surface clearly appeared, decreasing of the density
and diameter of the ijuk fibers. The change of the ijuk fiber properties
leads to increase the mechanical properties of PLA composites
reinforced the ijuk fibers through strengthening of the mechanical
interlocking with the PLA matrix. An addition to enhance the
distribution of the fibers in the PLA matrix, the stirring during DCM
solvent evaporation from the mixture of the ijuk fibers and the
dissolved-PLA can reduce amount of the trapped-voids and fibers
pull-out phenomena, which can decrease the mechanical properties of
the composite.
Abstract: Arenga pinnata is an abundantly natural fiber that can be used for sound proof material. However, the scientific data of acoustics properties of Arenga pinnata was not available yet. In this study the sound absorption of pure arenga pinnata was measured. The thickness of Arenga pinnata was varied in 10 mm, 20 mm, 30mm, and 40mm. This work was carried out to investigate the potential of using Arenga pinnata fiber as raw material for sound absorbing material. Impedance Tube Method was used to measure sound absorption coefficient (α). The Measurements was done in accordance with ASTM E1050-98, that is the standard test method for impedance and absorption of acoustical materials using a tube, two microphones and a digital frequency analysis system . The results showed that sound absorption coefficients of Arenga pinnata were good from 2000 Hz to 5000 Hz within the range of 0.75 – 0.90. The optimum sound absorption coefficient was obtained from the thickness of 40 mm. These results indicated that Arenga pinnata fiber is promising to be used as raw material of sound absorbing material with low cost, light, and biodegradable.