This paper deals with the testing of tensile and flexural behaviour of epoxy-reinforced natural fibre composites, for which Banyan fibres have been selected as the natural fibre. Variations are made in the orientation of the fibres to determine which orientation made the composite the strongest. The fibre strands are arranged in different orientations, such as the uniaxial, biaxial and criss-cross arrangements, to differentiate between the orientations and observe which arrangement exhibited the best mechanical behaviour. The fibres are initially washed with 0.5% weight/volume (w/v) NaOH solution, following which specimens of the composites are made using wooden moulds designed according to ASTM standards. Biaxial layers of E-glass are incorporated into the matrix in an attempt to enhance the mechanical properties of the specimen. The variances observed in the Young’s modulus are analysed to understand the factors that majorly impacted it. For a better understanding of the results, the chemical functional groups and the microstructure of the samples are analysed with the aid of Fourier-Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM) and X-Ray powder Diffraction (XRD). Additionally, predictive models are simulated using Artificial and Deep Neural Networks to recognise patterns in the data, by varying specific parameters. The results obtained indicated that Banyan fibre composites can replace conventionally-used materials and serve real-world purposes better.

Natural fibre composites are ideal material substitutes for combating the issues of pollution and non-biodegradability. Several industries, the automobile industry, in particular, have shown tremendous inclination towards the usage of natural fibre composites in their deliverables. Besides providing a wide array of useful properties, natural fibre composites have offered flexibility in terms of choosing various combinations of fibres and resins. Owing to this, this paper aims to collect data and categorize the natural fibre composites based on the types of treatments and properties they exhibit. Characterization was done by taking into consideration chemical and enzymatic treatments as well as tests such as the tensile, flexural, compressive, impact, shear and hardness. Based on the values obtained from the characterization, the paper suggests suitable and feasible natural fibre composites as biocompatible replacements to conventionally used materials in the automotive industry.

A successful attempt has been made to develop coir fibre composites reinforced with graphene, epoxy and carbon fibre. The carbon fibres were arranged in an intercalated manner, which is similar to the coir fibres. The percentage composition of graphene was varied as 1, 2, 4 and 6% by weight of the holding matrix. Suitable surface modifications were done by treating natural fibres by 5% NaOH and 0.3% KMnO4 for better adhesion of fibre and epoxy resin. Sonication and cetyl trimethyl ammonium bromide treatments were also done to achieve the fine scattering of graphene in the epoxy matrix in order to achieve better mechanical behaviour. Moulds were made as per D638 American Society for Testing and Materials (ASTM) standards. The treated fibres were then arranged in the mould by the conventional hand layup technique. Tensile testing was carried out to determine the mechanical properties of the composites. Two-way analysis of variance was used as a statistical tool to find the effect of parameters such as ‘Percentage composition of graphene’ and ‘Type of mould’ on the modulus of the composites. Fourier transform infrared spectroscopy was conducted to determine the interferential adhesion and homogeneous distribution of fibres in the composite matrix. At last, field emission scanning electron microscopy analyses were also done to the specimens before and after tensile testing to determine the morphology of different entities present in the composites.

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The review paper emphasizes mainly on the hybridization of coir fiber and spider silk with carbon fiber and different percentage compositions of graphene, with an ultimate aim as to how the strength of these hybridized composites can contribute in the fields of material and manufacturing engineering. Firstly, there is an analysis of different properties of coir, carbon fibers, graphene and spider silk. Secondly, there is an analysis of the ballistic test performed on the specimens. In this review, some very basic yet important information is collected and discussed which will help the future researchers in the preparation of hybrid composites involving graphene. Being a natural fiber, the bristle coir fibers are pre-treated with alkali (NaOH) and then acidic treatment is done to remove the excess alkali. After the fibers become neutral, permanganate treatment is done. In case of spider silk, no pre-treatment is done. These fibers are reinforced with epoxy and different weight percentage of graphene (1wt%, 2wt%, 4wt%, 6wt %). Carbon fibre is incorporated in between using conventional hand layup technique. The epoxy and graphene mixture is sonicated to make sure that a uniform and good mixture is obtained. The review facilitates to perform ballistic test on the samples as the results from this test can substantiate to deliver a vital improvement in the field of material selection for body armors.