PENGARUH FRAKSI VOLUME SERAT TERHADAP SIFAT MEKANIS DAN FISIS KOMPOSIT HIBRID KENAF/ SILICA FUME /EPOXY
Abstract
Composite reinforced with kenaf fiber (Hibiscus Cannabinus) has been developed
in the automotive industry specifically for interior and exterior cars. However, for the
automotive application, the mechanical properties of the natural fiber composite have to
improve. Manufacturing the hybrid composite is one of the ways to enhance the
mechanical properties of the composite. In this research, the hybrid composites of
kenaf/silica-fume/as epoxy were fabricated to study the effects of volume fraction of the
fillers (kenaf and silica- fume) on bending and impact properties of the composites, and
also water absorption and thickness swelling properties.
In this research, alkali-treated kenaf/silica-fume/epoxy hybrid composites were
fabricated using a hot press molding, at 100oC, and the pressure of 1,449 MPa and 0.967
MPa for bending and impact specimens, respectively. Kenaf fibers were alkali-treated by
soaking in 6% NaOH for 36 h and then chopped into ± 5 mm length. The ratio of volume
fraction of kenaf fiber used is 15, 20 and 30%. Silica particles used were 2% with a size
of 37 μm (400 mesh). Impact and bending tests of the composite specimens were
conducted according to ASTM D6110 and ASTM D790, respectively. Physical
examination of water absorption and thickness swelling was carried out according to
ASTM D570-98 with a soaking time of 216 h. The impact fracture surface of the
composite specimens was characterized by scanning electron microscopy (SEM), and the
fiber distribution was observed with an optical microscope.
The results showed that the highest impact strength, bending strength, and
modulus of elasticity are 7.49 kJ / m², 59,180 MPa, and 4,658 GPa, respectively, that
were obtained from the hybrid composites with 30% fiber content. However, the lowest
water absorption of 6.14% resulted from the hybrid composites with 15% fiber content