KARAKTERISASI SIFAT MEKANIS KOMPOSIT LAMINAT KENAF ALKALISASI/(PP + HDPE) DENGAN VARIASI PERBANDINGAN PP DAN HDPE
Abstract
Composite materials are currently being developed by the automotive industry as car exterior panels, especially on car bumpers due to their light weight and recyclable. There are two types of hybrid composites: i.e., hybrid composites use two types of fibers in a matrix, and two kinds of the matrix with a type of fiber. Research on hybrid composites with two types of fibers has been extensively studied. However, few studies on hybrid composites using two types of matrices. In his work, the hybrid composites of kenaf fiber with two kinds of matrices polypropylene (PP) and high-density polyethylene (HDPE) were fabricated to study the effect of the ratio of PP/HDPE toward the impact toughness of the composites.
Before fabrication, kenaf fibers were treated by immersing the fibers into 6% NaOH solution for 4 hours at room temperature and then chopped to be 6 mm length. The volume fraction of fiber and matrix was 30%: 70% and the ratio of PP/HDPE was varied to be 1:2, 1:1 and 2:1. The hybrid composites were fabricated with hand lay-up technique in a hot compression molding at 165℃ - 180℃ and 1800 psi for 15 minutes. Impact tests on the composite specimens were conducted according to ASTM D 5942. An optical microscope was used to characterize the fiber distribution and the fracture surface.
The results showed that the highest impact toughness 0.028 J/mm2 reached by the kenaf/(1PP+2HDPE) hybrid composite. An increase of the volume fraction of HDPE increased the impact toughness of the composite. The fiber distribution in the matrix seemed to be uniform in all composites with almost no voids were found, as confirmed in the optical micrographs.