Production and analysis of physio-mechanical properties of jute and hemp fiber reinforced unsaturated polyester matrix hybrid composites

Today, the environmental problem is a major concern around the world. Although synthetic fiber reinforced composites have wide applications in different fields due to their higher mechanical strength and stiffness, their processing and production is still a major source of environmental hazards. The main disadvantages of natural fiber reinforced composites (NFRC) are their low mechanical strength, less adhesion between fiber and resin, which can be compensated by hybridization of fibers and surface treatment. In this study, three different fiber-reinforced polyester resin hybrid composites with hemp and jute fibers, 30%, 50% and 70% by volume, were produced and the analysis of the mechanical properties of the composites was investigated. Before the reinforcement process, the fibers were subjected to alkali treatment with 3% and 5% NaOH concentration in order to eliminate the adhesion problem between the fiber-matrix and improve the mechanical properties. The composites were produced by hand lay-up method in hybrid form with varying layer arrangement of jute (J) and hemp (H) fibers (J/H/H/J and H/J/J/H). The composites were subjected to mechanical tests for tensile, bending and impact strength. Among all composites, 3% alkali treated composites were found to have the best tensile strength, tensile modulus, flexural strength, flexural modulus and impact strength compared to the others. 30% fiber reinforced composites showed the best tensile strength, tensile modulus and 70% fiber reinforced composites showed the best flexural and impact strength. In terms of fiber layer, J/H/H/J hybrid fiber layer composites exhibited better mechanical properties than H/J/J/H layer composites, except for impact strength. Keywords: Natural fiber reinforced composite, Hemp fiber, Jute fiber, Sodium hydroxide, Tensile strength, Flexural strength, Impact strength.