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This century has observed unusual improvements in green materials through the development of biocomposites due to anxieties about the atmosphere and sustainability issues. These biocomposites can be effectively disposed of at the final existence without harming the environment, which is impossible with man-made fiber-based polymer composites. The natural fiber is not a problem-free option, and they maintain some shortfall features that are the considerable moisture assimilation and very anisotropicity. This review paper intends to give a short outline of various surface modification methods to improve the fiber–matrix adhesion influencing the significant enhancement of the mechanical properties of the biocomposites.

Due to the dominating advantages of natural fibres such as biodegradability, eco-friendliness, nominal cost, low density and high specific strength, they are being used opposite to synthetic fibres in many industrial applications. Despite many advantages, these fibres face some limitations such as higher moisture uptake, quality variations, low thermal stability, and poor compatibility with polymeric matrix. To overcome these limitations, chemical treatments of these fibres were found to be the most suitable method to improve adhesion with polymers, increase their strength and water absorption resistance, and improve their composite properties also. Among chemical treatments, alkali treatment is the most widely used and versatile surface modification method of the natural fibres. A good number of research works have been carried out on effect of alkali treatment on the properties of natural fibres and its composites, which motivated for this review. In this paper, the effect of alkali treatment on the properties of natural fibres has been reviewed. In addition, the physical and mechanical properties, thermal analysis and tribological behaviour of its biocomposites are also reviewed. It was concluded that alkali treatment of natural fibres could provide enhanced properties of various bio-composites up to a great extent.

The aim of present study is to overcome the limitations of natural fibres and its polymer based composites. In present work, a new approach as PLA coating of sisal fibres has been used. Hand lay up technique was used to fabricate the polyester based composites using alkali treated and PLA coated sisal fibres. Static analysis in terms of tensile and flexural test, and dynamic mechanical analysis in terms of storage modulus (E’), loss modulus (E”), damping (Tanδ) and glass transition temperature (Tg) was carried out. In addition, morphological analysis of fractured surface of the composites was performed using scanning electron microscopy (SEM). The results revealed that composite with PLA coated sisal fibres showed better mechanical performance than alkali treated and untreated sisal composites.

Nowadays, it has been global demand to overcome the abundant use of synthetic fibres with respect to save the environment. Sisal fibre is one of the widely used natural fibre and being used as rein...

The influence of pre-straining process on dynamic fracture behavior of Cu-strengthened high-strength low-alloy (HSLA) of varied amount of pre-straining has been investigated in the current study. The influence of pre-straining on deformation due to tensile loading and on ductile fracture behavior of the steel has been carried out with the help of instrumented Charpy test and standard fracture test. Study of microstructure, its hardness, and tensile properties has been done to understand and correlate these properties with Charpy and dynamic fracture behavior of the investigated steel. Prior to the machining of the specimen, the stock materials are pre-strained at different levels. All the Charpy V notch (CVN) specimens are fatigue pre-cracked to generate natural crack. The pre-crack length was restricted to 5 mm (a/w = 0.5). Force–time behavior curve and the force–displacement curve is determined by double numerical integration of force–time curve. In the investigated steel, normalized energy increased slightly up to a level of 2% pre-strain and then decreased by increasing pre-strain level greater than 2%. The dynamic fracture toughness first increases up to 2% and then decreases beyond 2% pre-strain indicating the influence of pre-strain on dynamic fracture toughness behavior of steel. The fracture surface of investigated steel has been examined under scanning electron microscopy. This study has been also focused to understand (i) The nature of the stretch zone—a featureless band that forms prior to initiation of ductile fracture and (ii) the micromechanism of slow stable crack growth.

This is the first investigation aimed to enhance the mechanical, thermal and viscoelastic properties of epoxy based sisal composites using eco-friendly treatment (i.e. NaHCO3 treatment) followed by eco-friendly polymer coating (i.e. PLA coating). The composites were fabricated by manual method with a constant content and length of fibres as 16 wt% and 15 mm, respectively. Mechanical tests on the prepared samples were performed in terms of tensile, flexural, impact and hardness. The thermal stability of the prepared composites was also measured by TGA analysis, whereas viscoelastic properties were measured by dynamic mechanical analysis. Moreover, morphological analysis of tested samples was also carried out by SEM. Tensile and flexural performances of treated and coated composites were found to be greater than those of untreated and treated sisal composites, whereas impact strength was found to be reduced. The treated and coated composite SC(T2) has 34.80% and 27.46% more values of tensile strength, and has 19.69% and 8.54% more values of tensile modulus as compared to those of untreated composite SC and treated composite SC(T1), respectively. There was a nominal improvement of 6.76% and 1.33% in the hardness of composite SC(T2) than those of composites SC and SC(T1), respectively. Thermal stability, storage modulus and glass transition temperature were also considerably improved owing to treatment followed by coating of the fibres.

Natural fibres are gaining attention day by day in industrial applications. The aim of current investigation is to enhance the performance of sisal fibre by its surface modifications. The surface modifications include alkali treatment with varying concentrations (2, 5, 10, 15 & 20 %) and coating of PLA with varying concentrations (2, 4, 6, 8 & 10 %). Treated and untreated sisal fibres were subjected to tensile test and thermo gravimetric analysis (TGA). In addition to this, sisal fibres were characterized by X-ray diffraction (XRD), and its structural morphology was studied by scanning electron microscope (SEM). Moreover, FTIR spectroscope analysis was also carried out to see the removal of hemicelluloses and lignin from sisal fibre by alkali treatment. It was observed that surface modifications had much influenced the performance of sisal fibre. On other hand, PLA coated fibre had a better performance than alkali treated fibre.