Flexural Property and Water Content of Unidirectional Polypropylene/Subang Pineapple Leaf Fiber Composites

The development of natural fiber reinforced composite research has shown significant results. Pineapple leaf fiber reinforced composites for non-structural application provide added value for Subang pineapple leaf fiber (PALF) waste. This study aimed to observe flexural strength, water absorption and desorption of composites which referred to the Indonesian National Standard (SNI) for composite board. Alkali treatment on Subang PALF was performed to improve the interface bonding between PALF with polypropylene (PP), in which the PALF was soaked in 5% NaOH solution for 24 hours. Treated PALF and PP sheets were fabricated using compression molding (hot press) technique with the variation of fiber fraction to polypropylene were 20 wt%, 30 wt% and 40 wt%. Flexural property, desorption and absorption water tests were conducted on PP and PP/PALF composites, and Optical Microscope (OM) observation was performed on the surfaces after the flexural test was conducted. The highest flexural strength and flexural modulus were (4.89 ± 0.37) MPa and (1.13 ± 0.43) Mpa respectively, these values shown an increased respectively by 153,37% compared to the pure PP. Then the desorption and the absorption water tests-were (1.08 ± 0,12) % and (8,83 ± 3,35) % respectively. The morphology of flexural tested composites indicated that matrix failure; and it showed that there was a strong interface bonding between the fiber and matrix. (paper)