Composite materials reinforced with biofibers and nanomaterials are becoming considerably popular, especially for their light weight, strength, exceptional stiffness, flexural rigidity, damping property, longevity, corrosion, biodegradability, antibacterial, and fire-resistant properties. Beside the traditional thermoplastic and thermosetting polymers, nanoparticles are also receiving attention in terms of their potential to improve the functionality and mechanical performances of biocomposites. These remarkable characteristics have made nanobiocomposite materials convenient to apply in aerospace, mechanical, construction, automotive, marine, medical, packaging, and furniture industries, through providing environmental sustainability. Nanoparticles (TiO2, carbon nanotube, rGO, ZnO, and SiO2) are easily compatible with other ingredients (matrix polymer and biofibers) and can thus form nanobiocomposites. Nanobiocomposites are exhibiting a higher market volume with the expansion of new technology and green approaches for utilizing biofibers. The performances of nanobiocomposites depend on the manufacturing processes, types of biofibers used, and the matrix polymer (resin). An overview of different natural fibers (vegetable/plants), nanomaterials, biocomposites, nanobiocomposites, and manufacturing methods are discussed in the context of potential application in this review.

The coir fibers could be used as prominent biocomposite materials.

A mathematical model describing the shear rate and pressure variation in a complex flow field created in a hydrodynamic cavitation reactor (stator and rotor assembly) has been depicted in the present study. The design of the reactor is such that the rotor is provided with surface indentations and cavitational events are expected to occur on the surface of the rotor as well as within the indentations. The flow characteristics of the fluid have been investigated on the basis of high accuracy compact difference schemes and Navier-Stokes method. The evolution of streamlining structures during rotation, pressure field and shear rate of a Newtonian fluid flow have been numerically established. The simulation results suggest that the characteristics of shear rate and pressure area are quite different based on the magnitude of the rotation velocity of the rotor. It was observed that area of the high shear zone at the indentation leading edge shrinks with an increase in the rotational speed of the rotor, although the magnitude of the shear rate increases linearly. It is therefore concluded that higher rotational speeds of the rotor, tends to stabilize the flow, which in turn results into less cavitational activity compared to that observed around 2200-2500RPM. Experiments were carried out with initial concentration of KI as 2000ppm. Maximum of 50ppm of iodine liberation was observed at 2200RPM. Experimental as well as simulation results indicate that the maximum cavitational activity can be seen when rotation speed is around 2200-2500RPM.

Coir is one of the most important natural fibers having significant potentiality in structural biocomposites production. The long coir fiber (LCF) and short fibrous chips (CFC) were extracted from the husk of coconut. The dimensions of the CFC were within 1.0–12.5 mm and the LCF were within 2.0 mm. All the fibers and fibrous chips were treated with 5% NaOH (alkali) before the biocomposite manufacturing. Different percentages (8%, 10%, and 12%) of melamine-urea-formaldehyde (MUF) were used to produce the tri-layered medium density composite panels with 12 mm thickness. The mechanical properties (tensile, flexural, and internal bonding strengths) of coir reinforced multilayered composites has been studied for all the produced biocomposites. The morphological, micro-structural, and bonding mechanisms were investigated by Scanning electron microscope and Fourier-transform infrared spectroscopy analysis. Thermal properties of the biocomposites were studied by thermal conductivity, thermogravimetric analysis, and derivative thermogravimetry characterization. The moisture contents of the final composite panels were also investigated in this study. The main objective of this work is to investigate the influences of MUF on treated coir fiber and fibrous chips reinforced tri-layered biocomposites. Beside, a novel sustainable product is developed through reinforcing the fibrous chip with coir fiber in terms of multilayered biocomposite panels.

Fabric-based laminated composites are used considerably for multifaceted applications in the automotive, transportation, defense, and structural construction sectors. The fabrics used for composite materials production possess some outstanding features including being lighter weight, higher strength, and lower cost, which helps explain the rising interest in these fabrics among researchers. However, the fabrics used for laminations are of different types such as knit, woven, and nonwoven. Compared to knitted and nonwoven fabrics, woven fabrics are widely used reinforcement materials. Composites made from fabric depend on different properties such as fiber types, origin, compositions, and polymeric matrixes. Finite element analysis is also further facilitating the efficient prediction of final composite properties. As the fabric materials are widely available throughout the world, the production of laminated composites from different fabric is also feasible and cost-effective. This review discusses the fabrication, thermo-mechanical, and morphological performances of different woven, knit, and nonwoven fabric-based composites.

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The development of sustainable and innovative products through solving the constantly raising demands of end users is one of the significant parts of research and development. Herein, the development of a green composite is reported with the reinforcement of naturally originated flax and artificial glass woven fabrics through incorporating with the methylene diphenyl diisocyanate (MDI) resin. The glass fabrics were treated with silane and flax fabrics by using NaOH before the composite production to increase the affinity of fibers toward the resin. Composite panels were developed with four different ratios of glass and flax woven fabric reinforcement (100/0, 83.33/16.67, 50/50, and 0/100) to investigate their performance with the MDI resin. The composites were characterized by tensile and flexural analysis to investigate the mechanical performances. The thermogravimetric characteristics of the composites were examined for checking the thermal stability of the produced composites. The surface morphology was investigated for observing the surfaces of the composites before and after applying tensile loads. Scanning electron microscopy (SEM) deployed EDX linear scanning was used for ensuring about the signals of different chemical constituents into the matrix. Fourier transform infrared spectroscopy (FTIR) was conducted for finding out the fingerprint of the chemical elements of the produced composites. Besides, the water absorption and moisture content tests were also conducted to examine the moisture absorption by the pure glass, flax, and hybrid composites. Further, statistical analysis of variances was performed to test the significance of the differences in the mechanical properties of the individual types of the composites developed. For investigating the relationship between the proportion of woven glass fabric in the reinforcement and the mechanical properties, regression analysis was used. The ANOVA test was also examined for checking the significance of the mechanical properties of the composites.

This study investigated about the developments of insulation panels from multilayered coir long and short fiber reinforced phenol formaldehyde polymeric (PF) resin. The lengths of coir long fibers (CLF) were within 3 mm, whereas the short fibers (CSF) ranged from 0.1 mm to 1.25 mm. Four composite panels of 360, 680, 800, and 1000 kg/m3 densities were developed by employing hot pressing technology. The thermal conductivity, microstructural, mechanical, and physical properties of the composite panels were investigated. Perceived thermal conductivity values ranged within 0.046280 (0.000494) to 0.062400 (0.001146) Wm‒1 k‒1of the composites demonstrating superior insulation properties. Moreover, the current study also found that mechanical and thermal properties showed improvement with the increase of density. Low-density fiberboards had the lowest performances compared to high-density composite panels, with the exception of the 1000 kg/m3 density, in which fiber agglomeration occurred. Furthermore, all the developed composite panels display superior potentiality for use as effective insulation materials. The FTIR (Fourier transform infrared spectroscopy) analysis also shows an efficient bonding between the cellulosic coir materials and PF resin. The overall characteristics of the composite panels, especially medium fiberboard, show prominent potential for industrial production units by fulfilling the consumer requirements.