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Composites with natural lignocellulosic fillers are being cited as a viable and sustainable alternative to conventional materials, as they combine lower costs with lower weight. In many tropical countries, such as Brazil, there is a considerable amount of lignocellulosic waste that is improperly discarded, which causes pollution of the environment. The Amazon region has huge deposits of clay silicate materials in the Negro River basin, such as kaolin, which can be used as fillers in polymeric composite materials. This work investigates a new composite material (ETK) made of epoxy resin (ER), powdered tucumã endocarp (PTE), and kaolin (K), without coupling agents, with the aim of producing a composite with lower environmental impact. The ETK samples, totaling 25 different compositions, were prepared by cold molding. Characterizations of the samples were performed using a scanning electron microscope (SEM) and a Fourier-transform infrared spectrometer (FTIR). In addition, the mechanical properties were determined via tensile, compressive, three-point flexural and impact tests. The FTIR and SEM results showed an interaction between ER, PTE, and K, and the incorporation of PTE and K reduced the mechanical properties of the ETK samples. Nonetheless, these composites can be considered potential materials to be used for sustainable engineering applications in which high mechanical strength is not a main requirement of the material.

The application of lignocellulosic fibers as reinforcements in composite materials has found increasing use in recent years, due to the attractive characteristics of natural fibers such as their low cost, high specific modulus, biodegradable, abundant and with many technical qualities. Natural fiber hybrid composites are very frequently used in the automotive industry. In this work, a computational and experimental analysis is carried out with the objective of comparing curauá fibers, jute and sisal fibers used in epoxy resin matrix composites for use in industry, determining the most appropriate hybridization effect by establishing the proportions and amounts of each fiber in a hybrid composite with better mechanical properties. To carry out the research, the Finite Element Method was first used, performing several models with different amounts of fibers which were later validated with mechanical tests. The number of Finite Element models and specimens performed was determined through the design of experiments using the Taguchi Method. As a result of the work, a greater strength of the hybrid composites made with greater amount of curauá fiber (20%), jute (10%) and lesser of Sisal fiber (5%) was obtained, both in the results obtained by the Finite Element Method and in the mechanical tests., Cite as: Garcia del Pino G. et al "Investigation on the mechanical property behaviour of the hybrid composites from natural Amazonian fibres by numerical and experimental method" in proceedings of 6th Brazilian Conference on Composite Materials (Part of ISSN 2316-1337). Organised and Edited by R.J. da Silva and T.H. Panzera, 2022, pp 387 - 392, DOI: doi.org/10.29327/566492.

Natural fibres have many advantages over synthetic ones, making them attractive for reinforcing polymer materials. This work evaluates the use of an Amazonian plant, namely Curauá (Ananas erectifolius), as a reinforcement phase of biocomposites fabricated by cold pressing. Curauá fibres have been shown to be a promising fibre for composite materials, especially due to their higher elastic modulus than other plant species. An L9 Taguchi design is used to investigate the effect of fibre fraction, NaOH concentration and immersion time on the tensile properties of biocomposites. Statistical models are able of predicting and revealing the optimal composition of the biocomposites. The tensile strength of Curauá biocomposites is significantly affected by the fibre fraction, followed by the factors of immersion time and NaOH concentration. High tensile strength is obtained by adding 25 wt.% of Curauá fibres treated under different conditions. There is an interaction between NaOH concentration and the immersion time; a higher concentration requires less time or vice versa to achieve ideal roughness, promoting strong fibre/matrix adhesion.