Balachandran. et.al / REST Journal on Emerging trends in Modelling and Manufacturing 5(4) 2019, 67-70 Copyright@ REST Publisher 67 Recent developments in the tensile properties of natural fibre reinforced composites: A review N. S. Balachandran, N.Badri Narayan Mehta, M.P.Jenarthanan, School of Mechanical Engineering, SASTRA Deemed University, India. 613401. jenarthanan@mech.sastra.edu Abstract Natural fibre reinforced composites dominate the field of engineering in the past few years. Many researchers do a lot of work in NFCs, trying increasing their mechanical performance especially make them suitable for day-to-day applications. Among the properties, tensile properties influence much as they aid design process, reduce material costs, and achieve lean manufacturing goals. Therefore, this review paper intends to administer an overview on the tensile properties of natural fibre reinforced polymer composites and explains achievements made with them. The study started by analysing and understanding the tensile properties of different natural fibre composites and modifications made in them to improve their tensile properties as expressed by several authors through their articles. The various experimental setups, resins, matrices and specimens used were noted and briefly explained here. It was found that by increasing the tensile strength value of NFCs, their application can be increased. Still, further work can be carried out to improve tensile strength of natural fibre composites. NFCs play a major role in automotive industry, building and construction, fishing nets, wall decorators etc. Keywords: Fibre loading, Surface modification, reinforcement, hardness, strength, tensile strength. 1. Introduction A polymer matrix imbedded with high-strength fibres yields a fibre reinforced polymer (FRP). Since natural fibres have advantages over conventional glass and carbon fibres they are used as an alternative reinforcement in polymer composites in the past few decades. Some examples for natural fibres are flax, hemp, jute, sisal, kenaf, coir, kapok, banana, vetiver, basalt, sugar palm etc. Some advantages of natural fibres include low cost, low density, comparable specific tensile properties, non- abrasive to the equipments, renewability, recyclability and bio-degradability. These composites are widely used for aerospace, construction, sport, packaging and automotive industries as mentioned earlier. There are many factors that can influence the performance of natural fibre reinforced composites. They are Fibre selection, Matrix selection, Interface strength, Fibre dispersion, Fibre orientation, Manufacturing, and Porosity. Table 1 shows the review of different properties of different NFCs obtained from different research articles. To yield the optimum composite products, with desired properties, suitable processing techniques and parameters must be carefully selected. This article aims to review the reported works conducted by researchers on the effects of various parameters on tensile properties of natural fibre reinforced composites. (Taken in Table. 1) 2. Discussions The most widely tested properties of natural fibre reinforced composites is tensile properties. Tensile strength can be defined as the ability of a material to withstand a pulling (tensile) force. It is measured in units of force per cross-sectional area (More conventionally N/mm 2 or M Pa). This is an important concept in material science, mechanical engineering and structural engineering. The fibre strength may influence selection of a specific natural fibre for a specific application. A tensile test reflects the average property through the thickness. The stresses in a tensile test are uniform throughout the specimen cross- section. From tensile test ultimate tensile strength, breaking strength, maximum elongation, Young's modulus, Poisson's ratio and reduction in area can be determined. Palmyra Palm ‘petiole fibre’ was prepared and characterized its tensile and surface characteristics. The reinforcement are untreated and treated palmyra palm petiole fibre. In Palmyra palm petiole chemically treated FRP composites, the highest tensile strength of 56.69 MPa, is achieved, and shown in figure 1. Whereas for untreated and chemically treated palmyra palm petiole fibres respectively, the tensile strength of 98.14, 156.13 MPa respectively is observed. This shows that the chemical treatment of the fibres resulted in increase in the tensile properties for all the specimens. Since poor bonding is present between the fibre and matrix, only with the reinforcement level of 12.19 %, the composites showed tensile strength of 50.15 Mpa which is higher than all other composites reinforced with untreated fibre at different volume fractions i.e. 20.18 – 33.22 %. (Nadendla Srinivasababu et al. (Taken in Figure. 1). The tensile strength values of chemically treated fibres composites are greater than the tensile strength of untreated composites and the tensile strength of composites where coupling agents are used further increased. The tensile strength of untreated composites with coupling agents increased by 26.05% compared to untreated composites devoid of coupling agents for 40% fibre content whereas diazo treated composites containing coupling agent showed 5.67% hike in tensile strength than diazo treated composites devoid of coupling agents for the same fibre loading. The tensile strength of untreated composites containing REST Journal on Emerging trends in Modelling and Manufacturing Vol: 5(4), 2019 REST Publisher ISSN: 2455-4537 Website: www.restpublisher.com/journals/jemm