Study of tensile strength and morphology of polyester matrix composite materials reinforced Hibiscus tiliaceust bark powder as raw material of rear bumper vehicle

Fibrous composite materials continue to be researched and developed with the long-term goal of becoming an alternative to metal substitutes. Due to the nature of the fiber reinforced composite material, its high tensile strength, and low density compared to metal. In general, the composition of the composite consists of reinforcing fibers and a matrix as the binding material. The potential of natural fibers as a reinforcing composite material is still being developed and investigated. The research that has been done aims to determine the characteristics of the tensile strength of the composite strengthened with Hibiscus tiliaceust bark powder (HTBP) with alkaline NaOH and KOH treatment. The reinforcing material used is HTBP and the matrix is polyester resin, with volume fraction of 5%, 10% and 20% with an alkaline treatment of 5% NaOH and 5% KOH with immersion for 2 hours, 4 hours, 6 hours and 8 hours. Tensile testing specimens and procedures refer to ASTM D3039 standard. The results of this study showed the highest tensile strength of 34.96 MPa in the alkaline treatment of 5% KOH, soaking time of 8 hours with a volume fraction of 10% and the lowest tensile strength of 21.96 MPa of 5% KOH alkaline treatment, soaking time of 6 hours with a volume fraction of 20%. .with 10% volume fraction of 34.96 MPa and the lowest tensile strength was 5% KOH alkaline treatment at 6 hours immersion with 20% volume fraction.