The Effect of Alkali Treatment Duration on the Tensile Strength and Physical Properties of Polyester Composites Reinforced with Coconut Fiber

Abstract

This study aims to determine the effect of alkali treatment duration with NaOH on the tensile strength and physical properties of coconut fiber-reinforced composites. The method used in this study was experimental, with variations in the duration of alkali treatment: 1, 2, and 3 hours. A total of 15 specimens were used for tensile testing. The specimens were prepared by hand lay-up, and tensile testing was conducted according to ASTM D638. The collected data were analyzed descriptively and presented in tables and graphs. The results of this study indicate that the duration of alkali treatment on fibers can affect the tensile strength and physical properties of polyester composites reinforced with coconut fiber. The results of this study show that the highest tensile strength was obtained at an alkali treatment duration of 1 hour, with a value of 19.322 MPa, and the lowest tensile strength was obtained at 2 hours, with a value of 13.826 MPa. The highest elastic modulus was observed at an alkali treatment duration of 3 hours with a value of 16.842 MPa. The lowest elastic modulus was observed at an alkali treatment duration of 1 hour with a value of 12.857 MPa. The microstructure photos were consistent with the tensile strength, i.e., the fewer defects in the fracture, the higher the tensile strength.