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This experimental investigation focused on coating of functionalized graphene oxide (FGO) on the mild steel to minimize corrosion, using a new method. Prior to the coating, the fundamental chemical and morphological structures of FGO were studied with aid of some characterization techniques: X-ray diffraction (XRD), Raman, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Various epoxy/FGO coating formulations with 10, 20, 30, 40 and 50 ppm of FGO were prepared and coated on the mild steel substrate, adopting dip coating method. Immersion test was carried out to observe the corrosion inhibition efficiency of the graphene. The adsorption isothermal behavior was also studied using various models and compared with the data obtained from the experimental results. From the results obtained, the formation of irregular rough patches and separation of platelets like zebra lines indicated the formation of graphene nanoparticles, as observed through morphological analysis. The occurrence of sharp peak at 24.3° in the XRD pattern depicted the existence of graphene in nanoscale. Electrochemical impedance (EI) and potentiodynamic polarization (PP) studies reported the maximum corrosion inhibition efficiency of 87% at 50 ppm concentration of epoxy/FGO. It was evident that an increasing concentration of graphene exhibited significant corrosion resistance in both studies. The bonding energy of randomly oriented graphene platelets reduced the removal of metal, delaying the crack propagation in tortuous path on the coated surface. These results established the significance and applicability of this study in various relevant industries.

Mechanical, thermal, and water absorption properties of banana fiber and sisal fiber-reinforced epoxy biocomposites were evaluated with and without cashew nut shell (CNS) filler, either separately, or as hybrid biocomposites. Bidirectional woven mats were used to make composites by compression molding. The CNS filler content was 5% to 10%. Adding CNS filler of up to 5% improved the mechanical and thermal properties. Further increases in filler content above the threshold value diminished their mechanical properties due to poor dispersion and increased porosity. The maximum tensile and flexural strength were found as 43 and 92 MPa. The highest impact strength was obtained with the hybrid biocomposites with 5% filler. This was attributed to the toughening effect of phenolic compounds in the CNS. In addition, the thermal stability of the biocomposites was influenced by filler content. The biocomposites exhibited varying water absorption capacities as the filler content increased with the water uptake. Scanning electron microscopy (SEM) images showed the microsurface of the fractured samples and their interfacial bonding, fiber pull-out, and fracture. However, increasing filler content in the biocomposite reduced the filler pull-out and led to fiber breakage.

The development of biodegradable hybrid fibre composites is gaining pace in the automotive and construction industries due to their lightweight structural applications, which offer considerable benefits for the environment. In this present investigation, hybrid bio composites were fabricated using a compression molding machine with plain woven jute and aloe vera mats along with polyester resin as the matrix. Six types of hybrid biocomposite laminates were prepared by varying the stacking arrangement of jute and aloe-vera mats to analyse the impact of stacking arrangements on vibration damping and acoustic behaviour of these hybrid bio composites. From the results, it is concluded that the maximum value of natural frequency is obtained from the JJAJ type of composite. i.e., 157, 326, and 370 Hz for Modes I, II, and III respectively, due to good interlacing of fibres in the weft and warp directions. J/J/A/J (AJ3) hybrid bio composite has highest sound absorption coefficient of 0.47 at 3000 Hz, and a better transmission loss i.e 19.84 dB, according to the results of the acoustic research. The comparison of experimental and theoretical analysis was carried out, and found that experimental and theoretical values are closely related to each other.

Direct ink writing (DIW) has emerged as an innovative and efficient method for gel synthesis, presenting numerous advantages over conventional techniques. Leveraging a diverse array of raw materials, DIW offers precise control over gel construction, facilitating the fabrication of materials with larger pore sizes. This capability contrasts with traditional methods like ionic gelation, which typically produce a maximum pore size of 130 μm. The increasing demand for materials with exceptional adsorption properties, especially for effluent treatment, has driven extensive research in this domain. While traditional gel preparation methods remain valuable, they exhibit inherent limitations. Thus, there is a pressing need for more efficient and scalable approaches to gel synthesis. DIW serves as a superior alternative, providing enhanced control over printing parameters and enabling the customization of materials to meet specific requirements. This paper not only addresses the limitations of traditional methods but also highlights the benefits of utilizing DIW for gel formulation. Additionally, it offers an overview of commonly employed adsorption isotherm and kinetic models and explores the applications of DIW-printed gels in effluent treatment. Given the expanding body of research in this area, this critical and comprehensive review underscores the potential of DIW in the adsorption of pollutants from wastewater.

By leveraging the properties of natural or plant fibers and possibilities through three-dimensional (3D) printing technology, a composite filament was fabricated by incorporating newly isolated Cryptostegia grandiflora fiber (CGF), as a reinforcement with polylactic acid (PLA) by using a twin-screw extruder. The fabricated composite filament and pure PLA filament were 3D-printed, using fused deposition modeling (FDM). This study investigated the mechanical, physical, and thermal properties of the 3D-printed CGF reinforced composite filament samples. The mechanical properties of the samples fabricated with 10 wt% CGF were better than that of samples with pure PLA. In addition, impact, tensile, flexural strengths and hardness were increased by 35.6, 33.6, 14.1, and 1.7%, respectively, when compared with the sample with pure PLA. The fractured surface morphology of tensile samples showed a uniform distribution of CGF within the PLA. The addition of CGF improved the thermal stability of the 3D-printed CGF/PLA composite sample by 15%. Therefore, the printed structure could serve as an alternative material for various uses, considering contemporary concepts of sustainability, availability, environmental friendliness, and cost effectiveness.

Acrylonitrile butadiene styrene (ABS) polymer and carbon fiber reinforced acrylonitrile butadiene styrene (CF/ABS) spur gears were 3D-printed using fusion deposition modeling (FDM) with different fillet radii of 0.25, 0.50, and 0.75 mm. The performance of the fabricated gears was studied with the effect of fillet radius on varying load and speed conditions. The thermal properties of the gears were also investigated. The results indicated that 3D-printed CF/ABS spur gear exhibited better performance than the pure ABS. The 3D-printed CF/ABS gear with fillet radius of 0.25 mm recorded the highest wear and thermal stresses. However, the optimum performance was exhibited by the gear sample with highest fillet radius of 0.75 mm. Repeated gear tooth loading during service caused an increase in gear temperature due to the hysteresis and friction. Using optical microscopy, the tooth structures of both 3D-printed ABS and CF/ABS spur gears were analyzed before and after loading conditions to establish their failure mechanism. Evidently, various applications of the FDM 3D-printed spur gears depend on their different performances under loads and operating speeds. The methods and findings of this work can be regarded as helpful for future related work related to cellulosic reinforcing particles in a polymer matrix.

Both developed and developing countries around the world are increasingly utilizing biodegradable products and bio-based materials. This is required to curb rampant environmental pollution caused by synthetic materials and their by-products. In this study, banana and bamboo fibers were prepared from agricultural and industrial wastes, respectively. Banana and bamboo fibers were obtained with aid of mechanical and waste extractions, respectively. Both fibers were subjected to a retting process for 24 hours, using normal warm water at a room temperature (27 ± 3 °C) to remove the impurities. Then, a comparative investigation and analysis was conducted concerning their properties and applications. The biomass level, physical, and chemical properties, structure, experimental analysis, and moisture regain behaviors of the plant materials were studied. Additionally, the antibacterial property of the samples was discussed. The biomass level was measured per hectare for banana (36.1 tons) and per plant for bamboo (65%), and the physical and chemical properties were identified via some basic testing techniques. The molecular, crystalline, and morphology structures were observed using Fourier-transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy. Finally, the industrial applications were elucidated to establish the possibility of using both fibers as promising sustainable, renewable, recyclable, and eco-friendly materials.

In this study, composite materials were made from Carica papaya fibers (CPFs), as a reinforcing element in polypropylene (PP), polyester (P) and epoxy (E) matrices, using compression molding technique. Experiments were conducted to evaluate the input parameters with their output responses, specifically density and thickness. Various CPF reinforced PP, P, and E composite specimens with varied fiber orientations of 0°, 45°, and 90° as well as percentages of fiber contents of 10, 20, and 30 wt.% were prepared, according to the ASTM D 570 standard. From the results obtained, it was observed that CPF/E composites with fewer fraction of CPF and orientation of 90° exhibited less water absorption throughout the whole duration of immersion. Water saturated CPF/E composite specimen, designated as E8, with orientation of 0° and fiber content of 20 wt.% showed the highest tensile, flexural strengths, and Shore D Hardness of 119, 115 MPa, and 85, respectively. Also, CPF/E composite specimen (E7) with 90° and 10 wt.% recorded the lowest tensile strength of 32 MPa, and CPF/E composite (E3) with 90° and 30 wt.% showed the lowest flexural strength of 41 MPa. Hence, it was evident that optimum CPF reinforced polymeric composite can be used for some outdoor engineering applications.

This paper presents a study on extraction and characterization of the cellulose fiber from the bark of Erythrina variegate (EV) plant. Several tests were carried out on Erythrina variegata fibers (EVFs) to determine their properties. These included thermogravimetric analysis (TGA)/difference thermogravimetric (DTG), X-ray diffraction (XRD) analysis, Fourier transform infrared spectroscopy (FTIR) as well as morphological analysis, using scanning electron microscopy (SEM) and atomic force microscopy (AFM). From the results obtained, chemical composition of EVFs, such as cellulose, lignin, ash, and wax content of 70.60, 12.70, 8.60, and 0.24 wt.%, respectively, were recorded through standard chemical analysis. The maximum and average tensile strength of the EVFs were found as 6.06 ± 0.02MPa and 2.80 MPa, respectively. The thermogravimetric analysis on the fiber showed excellent stability with a char residue of 19.23% and a maximum degradation temperature of 349°C. The crystallinity index (CI) of 37.5% and crystalline size of 36.93 nm of EVFs were calculated through X-ray diffraction analysis. The morphological study established that EVFs possessed rough surface even in raw form. The density of EVF was obtained at 1412 kg/m3, which was higher than that of Grewia damine of 1378 kg/m3 and lower than that of jute of 1460 kg/m3.

This work explored the importance of quantitative observation through imaging methods of optical and electron microscopies on the mechanical properties of particulate polymeric composites. Egg shell powder (ESP) reinforced polypropylene carbonate (PPC) polymeric composites with different filler weight percentage (wt.%) from 1 to 5 wt.% were considered. A cost-effective Image Analysis Software (IAS) was developed to extract black particles from the original optical images. During this process, the optimal image can be reproduced based on its originality by controlling the threshold values from 0.1 to 0.6 in real time situation. Using one-dimensional (1D) Gaussian distribution analysis, the authentication of the particle distribution data was studied and linked to the tensile strength of the composites. The mean value of the particle area collected from the left and right side of the scattered curves has a significant effect on the tensile strength of the composites. The proposed model was validated by comparing the predicted statistical results with the measured tensile strength for different wt.% of ESP composites. From the results obtained, a close agreement of 99% accuracy was observed between the experimental results and the proposed model for the tensile strength of the composites. The innovative study provides more practical and quantitative knowledge on improved particulate polymeric composites, in addition to the detection of failure processes through optical/electron microscopic examination of images. Evidently, the proposed cost effective, accurate and less stressful model can be employed by several composite-based industries to correlate the tensile strengths of particulate polymeric composites with their morphological properties.

The objective of this research is to investigate the extraction and characterization of a particular kind of Indian bamboo family plant known as Bambusa bambos . The fibres were extracted from the bamboo plant in the form of strips using the retting process and separated as thin fibres after the stamping process. The extracted raw bamboo fibres were chemically modified in a 5% alkali solution. The thermogravimetric analysis (TGA), x-ray diffraction (XRD), and scanning electron microscopy (SEM) were used to investigate the thermal, crystalinity, and morphological properties of untreated and alkali (NaOH) treated bamboo fibres. The ASTM standard was followed for the chemical composition and tensile testing of raw and chemically treated bamboo fibres. In contrast to raw bamboo fibres, alkali-treated bamboo fibres had a 5% drop in hemicellulose concentration. In the alkali-treated state, weakly bonded containments were removed from the fiber's surface, exposing the cellulose over a wider surface area. As a result, the thermal stability of the alkali-treated fibres was enhanced as compared to raw bamboo fibres. The increased amount of cellulose content and decreasing aspect ratio of the alkali-treated bamboo fibers lead to increased tensile strength. A significant improvement in the crystallinity index (broad band width of the second peak) was observed in the alkali-treated condition, which may occur due to the removal of hemicelluloses. Based on their performance, the chemically treated bamboo fibres can be used as effective reinforcement elements for the development of polymer matrix composites in the automobile and construction industries.

The increasing global need to achieve sustainability in product development demands the use of biodegradable materials from renewable resources in many engineering applications. Accordingly, various natural fibers were explored as suitable reinforcement in polymer matrixes due to their low density and biodegradability. Hence, in this present work, a novel fiber reinforcement was extracted from the stem of the Cryptostegia grandiflora (CG) plant through a retting process and manual intervention. The extracted Cryptostegia grandiflora fibers (CGFs) were chemically treated using NaOH and silane. Various properties like crystal structure, chemical composition, surface morphology, and thermal degradation were studied using x-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR) Scanning electron Microscopy (SEM) and Thermogravimetric analysis (TGA). The increasing cellulose content and the removal of hemicellulose after the chemical treatment indicate the potential for this CG fiber as a better reinforcement element in polymers. The increasing trend of tensile strength was observed for the CG fiber in the following order: silane > NaOH > untreated conditions. Two-stage thermal degradation was observed in all the cases where the maximum thermal degradation was found at the silane-treated CG fibers. Based on their performance, the chemically treated CG fibres can be made into composites and used for structural applications.