Tensile properties of elephant grass fiber reinforced polyester composites

Elephant grass stalk fibers were extracted using retting and chemical (NaOH) extraction processes. These fibers were treated with KMnO₄ solution to improve adhesion with matrix. The resulting fibers were incorporated in a polyester matrix and the tensile properties of fiber and composite were determined. The fibers extracted by retting process have a tensile strength of 185 MPa, modulus of 7.4 GPa and an effective density of 817.53 kg/m³. The tensile strength and modulus of chemically extracted elephant grass fibers have increased by 58 and 41%, respectively. After the treatment the tensile strength and modulus of the fiber extracted by retting have decreased by 19, 12% and those of chemically extracted fiber have decreased by 19 and 16%, respectively. The composites were formulated up to a maximum of 31% volume of fiber resulting in a tensile strength of 80.55 MPa and tensile modulus of 1.52 GPa for elephant grass fibers extracted by retting. The tensile strength and the modulus of chemically extracted elephant grass fiber composites have increased by approximately 1.45 times to those of elephant grass fiber composite extracted by retting. The tensile strength of treated fiber composites has decreased and the tensile modulus has shown a mixed trend for the fibers extracted by both the processes. Quantitative results from this study will be useful for further and more accurate design of elephant grass fiber reinforced composite materials.