Microstructural and mechanical properties of alkaline-treated moonj fibre reinforced epoxy composite

Researchers are currently working to replace hazardous synthetic fibers with sustainable alternatives. The present work investigates the treatment of moonj fibre using sodium hydroxide (NaOH) followed by reinforcement with epoxy resin. Poor fiber-matrix adhesion and absorption of moisture are the main disadvantages of adopting natural fiber. These disadvantages of natural fibre may be improved by selection of an appropriate chemical treatment procedure. In the present work, moonj fibre is chemically treated with 1 %, 2 %, and 3 % NaOH for 4 hr. It has been found that fibers treated with 1 % NaOH for 4 h exhibit greater tensile strength compared to untreated fibers or those treated with different concentration. A hand lay-up process has been employed to develop moonj fibre reinforced epoxy composites with different fiber percentages (40 %, 50 %, and 60 %). This was done to investigate how the materials mechanical and morphological properties are impacted by the fiber contents and alkali treatment concentrations. The main findings of this study are the developed composites that have exhibited the better mechanical behaviour as compared to the pure epoxy matrix. The optimum tensile strength of 28.3 MPa, flexural strength of 121 MPa, and hardness value is 66.08 HV are observed for the composition of 50M50E composite (50 % moonj fibre and 50 % epoxy), respectively with strong interfacial bonding as well. According to the test results, moonj fibre reinforced composite is a good lightweight substitute for traditional materials in applications involving car bodies and aerospace. To determine the surface topography and texture of the developed composite, scanning electron microscope (SEM) is employed. The developed composite can be used for the sustainable lightweight structural applications such as automotive interior components, including panels, trims, and lightweight structural covers and household product casings such as furniture panels, decorative boards, and lightweight enclosures etc. The novelty of the research work is a uniquely optimizes NaOH treatment for moonj fibre and identifies 1 % NaOH for 4 h as the most effective for enhancing fibre matrix bonding. It also demonstrates, for the first time, that a 50 % moonj fibre-50 % epoxy composite delivers significantly improved tensile, flexural, and hardness properties. The present work highlights moonj fibre as a new sustainable reinforcement for lightweight semi-structural applications.