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In this present study, the fused deposition modeling (FDM) method was used to fabricate the composites. Before three-dimensional (3D) printing, samples were designed according to the ASTM D256, D790 and D3039 standards for impact, flexural and tensile tests, respectively, using Onshape software before conversion to an STL file format. Afterward, the digital file was sliced with infill densities of 60%, 80%, and 100%. The composite samples contained chopped carbon fiber (cCF) and poly lactic acid (PLA), as reinforcement and matrix, respectively. The cCF/PLA (simply called cCFP) filaments were printed into various cCFP composite (cCFPC) samples, using a Viper Share bot 3D machine with different infill densities before the aforementioned mechanical testing. The tensile strength of cCFP were obtained as 25.9MPa, 26.9MPa and 34.75MPa for 60%, 80% and 100% infill density cCFP samples, respectively. Similarly, the flexural strength of cCFP were obtained as 11.8MPa, 12.55MPa and 18.4MPa and impact strength was 47.48kJ/m2, 48.45kJ/m2 and 48.96kJ/m2 for 60%, 80% and 100% infill density cCFP samples, respectively. The fractured/tested samples were examined and analyzed under a scanning electron microscope (SEM) to investigate the presence of fiber and void in the tensile sample. Based on the experimental results, it was evident that a high infill density of 100% with the highest reinforcement exhibited maximum impact strength, tensile and flexural strengths and moduli when compared with other lower carbon content of cCFPC samples. Therefore, the optimal 3D-printed cCFPC sample could be used for engineering application to benefit from properties of the polymer matrix composite materials and possibilities through additive manufacturing (AM). [ABSTRACT FROM AUTHOR]

Natural fibre reinforced polymer composites have found a wide range of applications in the automobile industry, construction industry and toy industry, and so on. In this research work, bidirectional aloe vera fibre mats were used as reinforcement and epoxy as matrix materials. Hand Layup process was applied for fabrication of aloe vera fibre reinforced epoxy matrix composites which contain different fibre orientations such as 45°, 60°, 75°, and 0°/90°. The goal of this research work is to obtain the influence of fibre orientation on mechanical and water absorption properties. The experimental investigations like tensile strength, flexural strength, impact strength, and the water absorption tests were performed. The surface morphology of the tensile failed test specimens were alsoanalysed using afield emission scanning electron microscope (FE-SEM). When compared to other fibre orientation composites, 0°/90° aloe vera fibre orientation has superior mechanical capabilities and 45° fibre orientation obtained minimum mechanical properties, according to the results of the experiment. As compared to 45° fibre orientation, 90° fibre orientation obtained 283.81%, 168.41%, and 202.54% higher tensile, flexural, and impact strength, respectively. [ABSTRACT FROM AUTHOR]

Due to the depletion of petro‐based sources and environmental consciousness, researchers are striving to replace synthetic fibers and resins in composites with bio‐sourced ones without compromising their properties. In this regard, the present study investigates the effect of partially replacing epoxy moieties with castor oil based bio‐resins on various properties of epoxy resin and its flax fiber reinforced composite system to achieve sustainable materials, thereby encouraging the bio‐based theme. Base‐catalyzed transesterification was used to synthesize epoxy methyl ricinoleate (EMR) as a low viscous reactive green monomer derived from epoxidized castor oil (ECO). The influence of both ECO and EMR bio‐resin on various mechanical, thermo‐mechanical properties, free mode vibration, and water absorption of epoxy and its composites were studied. The composition with 20% of ECO and EMR was optimized based on stiffness‐toughness balance. The inclusion of 20% EMR significantly escalated the tensile, impact, and fracture toughness properties of epoxy composites by 6.45%, 12.8%, and 14.2%, respectively. The strong fiber‐matrix interface was confirmed by increased pullout adhesion by 21% and 35.1% due to the addition of ECO and EMR, respectively. Dynamic mechanical analyzer revealed a 12% higher storage modulus for EMR modified composites than ECO counterparts. Scanning electron microscope morphology revealed superior interfacial adhesion between fiber and matrix in case of EMR modified bio‐composite, which resulted in a lower water diffusion coefficient than ECO modified bio‐composite. These results showed that the 20% EMR customized epoxy composite is dimensionally stable with improved mechanical properties and may act as a green alternative to petro‐sourced epoxy composites in automotive and semistructural applications. Highlights: Effects of castor oil based bio‐resins on epoxy composites are studied.Composites with significant bio‐content (~50 wt%) are developed.EMR modified epoxy composites exhibited improved mechanical properties.A strong fiber‐matrix interface was confirmed by increased pullout adhesion.Reduction in pot life of epoxy was observed on adding ECO and EMR. [ABSTRACT FROM AUTHOR]

In the present investigation, moringa oleifera and bamboo fibers extracted from Ethiopia are studied to understand their mechanical properties. Three types of woven composites namely moringa/epoxy, bamboo/epoxy and moringa/bamboo/epoxy (hybrid) are fabricated by maintaining 60 vol% fiber content. Additionally, neat epoxy samples are prepared for comparison. Tensile and flexural properties are investigated in terms of strength and modulus. Tensile test results depict brittle failure for all composites and infer increase in fracture strain of woven composites as compared with neat epoxy. Tensile modulus and strength of woven composites increase in the range of 19%–39% and 18%–281%, respectively as compared with neat ones. Flexural stress–strain profiles of neat epoxy, moringa/epoxy and moringa/bamboo/epoxy composites linear curves until failure indicating brittle mode while bamboo/epoxy composites shows non‐linear stress–strain profiles revealing non‐brittle mode of failure. Flexural properties exhibited by bamboo/epoxy and moringa/bamboo/epoxy reveal comparable properties to each other yet superior than moringa/epoxy and neat epoxy composites mainly attributed to the good bonding of constituents and compatibility. All the woven composites reveal an increase in flexural modulus and strength and are in the range of 31%–96% and 5.79%–51.12%, higher than the neat epoxy. Finally, fractured surfaces of specimens are analyzed using scanning electron microscope to understand the structure property correlations. [ABSTRACT FROM AUTHOR]

In order to investigate the effects of different functional groups on graphene on the mechanical behavior of carbon fiber reinforced epoxy composites were fabricated by hand layup technique. In this study, three different variety of functionalized graphene (–NH2, –COOH, and –OH) with varying weight percent (i.e. 0.1, 0.3, and 0.5 wt%) was considered. Tensile, interlaminar, and three-point flexural tests were conducted to evaluate the effects of graphene concentration and fiber stacking sequence (i.e. 0/90° and 0/90/ ± 45°) on composites. The microstructures of the composites were characterized by a scanning electron microscope. Experimental results showed that pristine and functionalized graphene significantly improved the mechanical properties of carbon fiber epoxy composites. Compared to neat carbon fiber epoxy composites, the maximum tensile strength of 33.34% and 26.35% were noticed for 0/90°–COOH–0.5 and 0/90/ ± 45°–NH2–0.3 stacked functionalized graphene modified carbon fiber epoxy composites, respectively. Moreover, 48.44% and 59.1% flexural strength were recorded for 0/90°–COOH–0.3 and 0/90/ ± 45°–OH–0.5 stacked functionalized graphene modified carbon fiber epoxy composites, respectively. Furthermore, maximum interlaminar shear strength (ILSS) of 120.25% was observed for 0/90/ ± 45° stacked carbon fiber epoxy composites. Finally, the results obtained with graphene as reinforcement filler can cause a significant improvement in the mechanical performance of fiber composites. Henceforth, they can also be considered as a promising candidate for designing composites for structural applications. [ABSTRACT FROM AUTHOR]

For commercial civil applications of laminated composite material, characterizations to forecast the interlaminar shear behavior and viscoelastic response across a wide temperature range are essential. In this study, the interlaminar shear strength (ILSS) of glass/epoxy (GE) composites dispersed with binary nanofillers nanosilica‐multilayer graphene (NS‐MLG) and nanosilica‐nanoclay (NS‐NC) was analyzed at an in‐situ testing temperature of 20, 70, and 110°C. Further, the viscoelastic property of the composites was studied using a dynamic mechanical thermal analyzer (DMTA) in the temperature range of 35–165°C. An increase in the ILSS value of around 9% and 10% was observed at room temperature for GE/MLG‐NS and GE/NC‐NS, respectively, compared to control GE composites. In contrast, the trend was seen to change at higher temperatures. There was a slight decrement in the storage modulus (E′) of GE/MLG‐NS and GE/NC‐NS composites in the glassy region compared to control GE composites. The mean Tg of the GE composite (control) was nearly 107.3°C when the E′ decline onset temperature was taken into account, but after the addition of MLG‐NS, it was 10.1°C below. The mean Tg of GE/NC‐NS was determined to be 106.3°C, and in the glass transition as well as rubbery regions, it was observed to compete with the E′ value of the control GE composites. Fractography was done using micrographs obtained from environmental scanning electron microscope (ESEM). Traces of polymeric material found at the fiber surface certified the improved interfacial adhesion between glass fiber and polymer in the matrix‐modified composite samples. [ABSTRACT FROM AUTHOR]

The potential advantage of plasma treated polyethylene (PEP) in mechanical properties was studied in this research. Recycled carbon fiber (CF) was the filler used for this hand layup technique. During fabrication, 4–14 wt% CF was incorporated into PEP and the results showed the impact of both filler and plasma treatment in enhancing the mechanical strength of polymer composites. Tensile results improved from 17.51 to 22.51 MPa in the polyethylene (PE) matrix. Scanning electron microscope (SEM) results showed untreated PE composites with fiber and matrix breakages as also voids reducing the compatibility of the PE/CF phases. The maximum flexural property of 25.5 MPa was observed in 10 wt% CF/PE treated with plasma. This combination was tried with different fabrication conditions in a temperature range of 180–220°C and time duration of 20–30 min. It was clearly seen that CF/PE combinations at a temperature of 180°C and time duration of 20 min had maximum tensile and flexural strength. The optimization using Taguchi method proved the significance of CF content in enhancing the mechanical properties. It also observed better tensile strength, flexural strength properties with 10 wt% CF, 180°C temperature, 20 min time from the results. Surface images of this condition showed more dispersed CF in the PE than other combinations due to optimum temperature and time duration during fabrication. [ABSTRACT FROM AUTHOR]

The present work is an attempt to study the effect of different surface treatments of flax fiber on the mechanical properties of the natural fiber reinforced natural rubber (NR) composites. In this study, flax fiber was chopped to 1, 1.25, and 1.5 cm in length and mixed with NR in two roll mill. The composite of 20%, 30%, 40%, and 50% fiber loading was prepared from each fiber length. Tensile analysis showed that a 1.25 cm fiber length composite of volume 40% has higher tensile strength compared to others. Hence, this optimized the fiber length and loading has opted for further study. Flax fiber was treated with NaOH and laccase and reinforced into an NR matrix. Properties like tensile strength, hardness, relative density, water diffusion, scanning electron microscope (SEM) and Fourier‐transform infrared spectroscopy (FTIR) for surface treated and untreated natural fiber‐reinforced NR composites have been investigated and compared. The reduction in the hydrophilic characteristics of the NaOH and laccase treated fiber was evident from FTIR analysis and increase in the crystallinity index of the fiber depicted by X‐ray diffraction (XRD) results. SEM analysis showed the enhanced interfacial interaction of treated flax fiber NR composite compared to untreated composite due to the removal of non‐cellulosic contents in fiber and an increase in the surface roughness after treatments. Further, an increase of 9% and 27.4% in tensile and tear strength was found in NaOH treated flax fiber reinforced NR composite. [ABSTRACT FROM AUTHOR]

This paper investigated the fracture toughness and enhancement mechanism for each component in bamboo-based composites at the cellular level. In situ characterization techniques identified the fracture behaviors of bamboo-based composites in three-point bending tests, and scanning electron microscope (SEM) further visualized the crack propagation of the fracture surface. In addition, the improvement mechanism of bamboo-based composites was illustrated by mechanical properties at the cellular level assisted with nanoindentation tests. Our in situ test results showed that the bamboo-based composites exhibited a longer deformation and higher bending load compared with bamboo. The fracture was non-catastrophic, and crack propagated in a tortuous manner in bamboo-based composites. Microstructural analysis revealed that phenol-formaldehyde (PF) resin pulled out and middle lamella (ML) breaking rather than transverse transwall fracturing occurred in parenchymal cells. The higher density of fibers in the bamboo-based composites triggered massive interfacial delamination in the middle lamella (ML), which was a weak mechanical interface. Furthermore, indented modulus and hardness illustrated that phenol-formaldehyde (PF) resin improved the mechanical strength of cell walls, especially parenchymal cells. The crosslinks of PF resin with the cell walls and massive fibers were the primary mechanisms responsible for the fracture toughness of bamboo-based composites, which could be helpful for advanced composites. [ABSTRACT FROM AUTHOR]

In recent years, many researchers have focused on the preparation of carbon and basalt fiber-reinforced composites. As a result, the composites have gained popularity as an alternative to traditional materials such as wood, steel, and aluminum. Carbon and basalt fibers were used in a bidirectional woven mat, with particulates varying from 0 to 15 wt% nanoparticle SiC. The hybrid laminates were fabricated through vacuum bag infusion methods. The novelty of the research work lies in studying the influence of nanoparticle SiC-combined carbon and basalt fibers arranged in six stacking sequences, with LY556 used as polyester matrix. Specimens were prepared and tested as per ASTM standards. Tensile, flexural, impact, and hardness tests were performed on the obtained specimens and average values were obtained. It was found that 15% SiC filler addition enhanced (20%) the mechanical properties. Scanning electron microscope photos revealed the bonding between the fiber mat and the matrix of thecrystal structure. The obtained tensile strength was 346 MPa and the flexural strength was 388 MPa. Dynamic mechanical analysis showed that mechanical properties were improved with the addition of 15% SiCnanoparticles. Hence, this method can be used to manufacture structural applications and automotive parts. [ABSTRACT FROM AUTHOR]

Chitosan (CS) fibers have been applied in various fields due to their biocompatibility, biodegradability, and antibacterial properties. However, weak mechanical properties remain as obstacles to further applications. Silk nanofibrils (SNFs) extracted from natural silk fibroin fibers preserve outstanding mechanical properties at the nanoscale, which are expected to impact structural programming and mechanical reinforcement for CS fibers. In this study, wet‐spun CS/SNFs composite fibers were continuously collected from NaOH/ethanol coagulation. Scanning electron microscope (SEM) results showed that SNFs were uniformly distributed in the CS matrix, and obvious orientation was observed when the mass ratio of SNF/CS was 75/100. Tensile tests showed that the introduction of SNFs significantly enhanced the mechanical properties of CS fibers when the mass ratio of SNF/CS was more than 25/100. With the increasing of SNF content, the tensile strength gradually increased, and the tensile strength and modulus could be increased 2.9 times and 3.5 times, respectively, when 100% SNF was added. The improvement of mechanical properties was partially attributed to hydrogen bonding between SNF filaments and CS, which was confirmed by FTIR and XRD results. This study provides a facile and eco‐friendly method to spin CS fibers with enhanced mechanical properties and a hierarchical structure. [ABSTRACT FROM AUTHOR]

The acrylic acid treated rattan fiber reinforced epoxy (RF/Epoxy) composite has been fabricated by taking various weight percentages (5, 10, 15, 20, and 25 wt%) of fibers using hand layup followed by compression molding technique. The optimum fiber loading has been determined by regression analysis and it is found that 18 wt% of rattan fiber gives maximum tensile strength. The interaction of rattan fiber with epoxy matrix has been studied by Fourier transform infrared spectroscopy and X-ray diffraction. Scanning electron microscope (SEM) has been used to study the morphology of chemically modified rattan fiber and RF/Epoxy composite. The mechanical, thermal, and dynamic mechanical thermal properties of 18 wt% RF/Epoxy composite have been studied as per ASTM standards. From the results, it is observed that RF/Epoxy composite gives best properties at optimum (18 wt %) fiber loading. The maximum tensile strength and flexural strength of the composite are found to be 47.5 and 121 MPa, respectively, which is better in comparison to other natural fiber composites used for manufacturing different automobile body parts. Hence, it can be concluded that 18 wt% RF/Epoxy composite can be considered as a potential candidate for automotive body parts. [ABSTRACT FROM AUTHOR]

This study is intended to improve the methodology to calculate the tensile properties of natural coconut fiber and increasing confidence in the use of sustainable natural fibers as reinforcing in composites used for different components in the naval industry. Coconut fiber is an agribusiness by-product that has been shown to have the potential for the development of new materials. The morphology of different species of coconut fiber was studied, and their mechanical tensile properties were determined. The coconut fibers were tested under direct tension in a universal testing machine, and the cross-sectional area of the fibers was calculated using images obtained in an optical microscope and a scanning electron microscope. The study assessed the incidence of key factors to determine coconut fiber mechanical tensile properties including different area measuring methods and the percentage of lumens present through an image analysis software called ImageJ. The results indicate that coconut fiber has a round-shaped cross-section, and the percentage of lumens is between 15% and 27%. Therefore, the effective area is reduced increasing the fiber's ultimate resistance to tension. [ABSTRACT FROM AUTHOR]

The mechanical behavior of banana fiber (BA) reinforced polymer composites filled with fly ash (FA) is analyzed in this present investigation. Polyester matrix is used to produce composites with 30% of banana fiber volume and fly ash with three separate volume fractions (1%, 3% & 5%). The failure mechanisms were identified through a scanning electron microscope using the fractured surfaces of the specimen after mechanical testing. The addition of 3% vol of fly ash results in an increase in the tensile, flexural, and impact strength of 46.3%, 24%, and 88.4% when compared with the banana fiber composites without fly ash (BAP). 5% vol of higher fly ash addition indicates a drop in the tensile, flexural, and impact properties of approximately 31.4%, 9.38%, and 30.61% when compared to 3% vol of fly ash added composites, respectively. Owing to weak interfacial bonding caused by the agglomeration of fillers, the higher filler loading results in subdued mechanical properties. With the help of SEM fractography, the parameters, including poor interfacial adhesion, defective surfaces, and fractures, were described. [ABSTRACT FROM AUTHOR]

In the present research, our aim is to study effects of alfa fiber content, alkali, maleic anhydride grafted polypropylene (MAPP), and the combined treatment (alkali and MAPP) on the tensile and flexural behavior of alfa fiber-reinforced polypropylene (PP) composites. These composites were produced using a single-screw extruder followed by an injection molding process. Both fibers and composites were characterized using optical and SEM microscope in order to evaluate the interfacial adhesion between the fibers and the matrix. From the main results, the tensile modulus and flexural strength of 30% untreated Alfa fiber/PP composites were found to increase significantly compared to those of PP. Meanwhile, there is no significant increase in terms of the tensile strength and the flexural modulus. Moreover, the composites with a combined treatment have shown significant effect on the tensile and flexural properties compared to untreated composites and the treated ones. The SEM observation of the morphology of alkali treated fibers exhibited an increase in the surface roughness because the removal of impurities. In addition, SEM photos of the fractured surface of composites reveal the improvement of the fibers and PP matrix interface quality by treatments, in particular the combined treatment. [ABSTRACT FROM AUTHOR]

Multimaterial designs consisting of metallic and polymeric material are aimed to reach high lightweight potential. This study presents novel hybrid structures with different interlayer of thermoplastic composites not previously reported in the literature for multi-laminated composites. The metal-polymer-metal hybrids comprise of polyamide 6 (PA6) or polyamide 6,6 (PA66) composite reinforced with 15% of short glass fiber as a sandwich layer. AA7075/AA2124-SiC-17p composite laminates are bonded through hot pressing connection. Mechanical properties of the structures are experimentally investigated from the point of maximum shear strength between dissimilar laminates, resistance to fracture and energy absorbing capacity. Scanning electron microscope (SEM) analysis of fracture surfaces is carried out after mechanical characterization. Short beam three-point-bending tests show that the laminate on which the load is applied is of great importance for the asymmetric hybrid structures. Shear dominant failure is only visible when the bending load is performed from the AA7075 surface. Single-edge notched bending (SENB) test results indicate that there is no significant difference between two configurations in terms of the Mode-I fracture toughness. V-notch Charpy impact tests reveal that the interlayer of PA6 composite contributes to a 13.15% more absorbed energy than that of the PA66 interlayer. [ABSTRACT FROM AUTHOR]

In the present study, a new composite based on epoxy resin reinforced with Lygeum spartum L. fibers was prepared using compression molding technique. Chemical, mechanical as well as morphological analyses were carried out on the Epoxy/Lygeum spartum composite (Epoxy/LS) using ATR-FTIR, tensile and flexural tests, and SEM spectroscopy. An increase in the intensity of several bands associated to the main complements of vegetable fibers (cellulose, hemicellulose, and lignin) was showan using ATR-FTIR analysis. An improvement in the mechanical properties of this new material was observed, with respect to the neat epoxy resin. This was of the order of 117 % and 85 % for tensile and flexural modulus respectively, and of the order of 40 % and 9 % for tensile and flexural strength, correspondingly. A good fiber-matrix adhesion was also observed from tensile fracture surface of composite using scanning electron microscope (SEM). All the obtained results demonstrated the effectiveness of the Lygeum spartum fibers as reinforcement of composite materials. [ABSTRACT FROM AUTHOR]

In this study, the effect of sonication time on the mechanical properties of graphene nanoplatelets (GnPs) glass fiber composites were discussed. The Sonication process is one of the best techniques to ensure uniform dispersion of nanofillers into the polymer matrix; otherwise, they form agglomerates of multilayers. To fulfill the massive demand for mass production, ultrasonic bath‐type sonication were deployed. In this study, 0, 1, 2, 3, 4, and 5 wt% of GnPs were added with epoxy at different sonication durations, precisely 0, 20, 40, and 60 min. Other sonication process parameters were kept constant with a sonication frequency of 28 KHz. Bidirectional glass fabric materials was used as reinforcement material in the fabrication of the laminates. In total, 21 laminates were fabricated using the hand lay‐up technique in various amalgamations. The tensile and flexural specimens were cut from the laminates as per the standards to determine their mechanical properties. The scanning electron microscope (SEM) images were used for the structural analysis of the glass fiber reinforced GnPs/epoxy composite. Surface morphology of GnPs becomes more wrinkled, resulting in a stronger graphene/epoxy matrix interface, enhancing the tensile strength and tensile modulus performance of the nano‐composites increases up to 37.12% and 66.30%, the flexural strength and flexural modulus performance of the nano‐composites increases up to 55.74% and 91.23% respectively. Based on the investigations, the influence of the GnPs percentage and the sonication duration for the preparation of the nano‐composites with the help of technique for order of preference by similarity to ideal solution (TOPSIS) optimization technique. [ABSTRACT FROM AUTHOR]

The need for eco‐friendly materials has been attracted due to renewability, abundance availability, low cost, and so on. Therefore, the search for bio fillers for the fabrication of bio‐based composite materials is gaining more and more attention in both academic and industry circles because it promotes sustainability. The present study represents the utilization of biomass solid waste in the hybrid form of Tamarind Seed and Date Seed Filler (TSF/DSF) into polymer reinforced composite which has been explored for the first time by a compression molding technique. These fillers are bio‐waste that can be obtained at a minimal cost from renewable sources. An attempt has been made to use these hybrid fillers to reinforce the matrix ranging from 0 to 50 wt%, and their physical, mechanical, and thermal properties were investigated. In general, the inclusion of hybrid fillers increases mechanical properties, although the addition of hybrid fillers had only a minor impact on thermal properties. When compared to the pure vinyl ester resin, the hybrid fillers reinforced composites revealed a significant enhancement in tensile, flexural, impact, and hardness properties, with improvements of 1.51 times, 1.44 times, 1.87 times, and 1.46 times respectively, at 10 wt% filler loading. Filler matrix interaction of fractured mechanical testing samples was evaluated by scanning electron microscope. Based on the findings, hybrid filler reinforced composites may be suitable for applications where cost is a consideration and where minor compromises in thermal qualities are acceptable. [ABSTRACT FROM AUTHOR]

The present work aims to demonstrate the effect of multiwalled carbon nanotube (MWCNT) on mechanical behavior and damage of woven carbon fiber/epoxy composites through experimental characterizations and multi‐scale modeling. Tensile tests were conducted for MWCNT/epoxy nanocomposites, and carbon nanotube (CNT) reinforced laminated open hole composites with different MWCNT weight ratios. The tensile modulus in CNT/epoxy nanocomposite was enhanced by 15.0%, 37.86%, and 22.86% for MWCNT reinforcement of 0.5%, 1.0%, and 1.5% wt, respectively. The corresponding improvement of tensile modulus for woven composites was 3.45%, 10.25%, and 1.53%; whereas tensile strength was increased by 19.76%, 25.78%, and 6.70%. The enhancement of tensile modulus and strength was less for 1.5% wt MWCNT laminates due to the formation of MWCNT agglomeration. The effective elastic isotropic/orthotropic properties for nanocomposite/woven composite were estimated through Mori‐Tanaka approach and numerical homogenization. The finite element simulations were performed with Hashin's damage model and extended finite element method‐based crack growth study. The delaminations between layers have been demonstrated through cohesive zone modeling. Damage propagation, interface delamination, and fiber/matrix failure were demonstrated by numerical simulations in line with scanning electron microscope observations. [ABSTRACT FROM AUTHOR]

Natural fibres are potential alternatives to synthetic fibres. Sago palm is a new type of natural fibre and has the potential same as other existing natural fibres. In this study, mechanical properties of sago palm / carbon fibre reinforce with epoxy hybrids were studied. Impact tests were conducted to study the impact properties of sago palm-carbon fibre reinforced epoxy hybrid composites. The hybrid composites contain woven sago palm fibre and carbon fibre reinforced with epoxy resin is produced by the vacuum compaction method. Each sample was prepared with different volume fractions such as 40%, 64% and 91% of composition sago palm fibre. After the preparation of composite material, mechanical properties tests were studied on the prepared sample. In addition, by using Scanning Electron Microscope Tests, the failure mode is investigated. It can be concluded that the 40% of sago palm fiber contain have the best impact behavior compared to the 64% and 91% of sago palm fiber loading because it’s high in impact resistance. [ABSTRACT FROM AUTHOR]

The present study examines the mechanical and morphological characteristics of a green composite reinforced with pineapple leaf fiber (PLF) under different environmental conditions. PLF underwent chemical treatment at optimal conditions, using a 1% w/v sodium carbonate solution for 6 hours, to produce an environmentally friendly pineapple leaf fiber (PLF)/polylactic acid (PLA)-based composite via injection molding. The optimal injection settings of 165℃ (melting temperature), 50 mm/sec (injection speed), and 110 bars (injection pressure) to produce the PLF/PLA composite. The PLF/PLA composite was developed with a fiber loading of 20% and a length of 3 mm. The produced PLF/PLA composites were then exposed to a variety of environmental conditions, including water, soil, refrigeration, and room temperature. The impact of these diverse conditions on the mechanical properties (tensile, flexural, compression, and shear) was scientifically observed for four-week. Additionally, the morphology of the fractured specimens was assessed using a scanning electron microscope (SEM). The contact angle measurement was conducted to assess the hydrophilic characteristics of the PLF/PLA green composite. There has been a lack of comprehensive research on the effects of different environmental conditions on the mechanical, wettability, and morphological properties of green composites derived from PLF/PLA. Thus, in this study, emphasis is given for investigating the effect of various environmental conditions on the mechanical properties of PLF/PLA injection-molded green composite. The composite material demonstrated the highest water absorption and swelling thickness at 6.45% and 5.51%, respectively, in comparison to the dry PLF/PLA samples. The green composite of PLF/PLA demonstrated excellent mechanical performance under ambient conditions compared to other environmental conditions. The PLF/PLA composite displayed a peak contact angle of 83.26° when subjected to soil burial conditions. On the contrary, the initial samples of the PLF/PLA composite displayed the minimum contact angle of 56.72°. • The mechanical behaviour was better in room temperature than refrigerating, soil burial, and water immersion conditions.. • The maximum water absorption and thickness of swelling were observed as 6.45% and 5.51% in comparison to the dry samples. • The soil buried composite samples showed maximum contact angle of 83.26°. • Morphological study showed minor damages to the samples exposed to refrigerator and room temperature conditions. [ABSTRACT FROM AUTHOR]

The application of epoxy resins in high temperature and thermal protection fields is limited due to their low decomposition temperature and low carbon residual rate. In this paper, epoxy resin (EP)/quartz fiber (QF) ceramifiable composites were prepared using a prepreg-molding process. The thermal stability, phase change and mechanical properties after high-temperature static ablation and ceramization mechanism of EP/QF ceramifiable composites were investigated. The addition of glass frits and kaolinite ceramic filler dramatically increases the thermal stability of the composites, according to thermogravimetric (TG) studies. The composite has a maximum residual weight of 61.08%. The X-ray diffraction (XRD) results show that the mullite ceramic phase is generated, and a strong quartz diffraction peak appears at 1000 °C. The scanning electron microscope (SEM) and element distribution analyses reveal that the ceramic phase generated inside the material, when the temperature reaches 1000 °C, effectively fills the voids in composites. The composites have a bending strength of 175.37 MPa at room temperature and retain a maximum bending strength of 12.89 MPa after 1000 °C treatment. [ABSTRACT FROM AUTHOR]

Delamination is always considered as a threat to the resin matrix composite laminates due to the nonvisibility from the outside. Much effort on the interleaving toughening has been made to improve the interlaminar fracture toughness. The synergistic toughening effect of thermoplastic resin and carbon nanotubes (CNTs) has been the topic in the interleaving toughening. In this study, the influence of the hybrid structure between thermoplastic polyetherketone‐cardo (PEK‐C) and CNTs on the toughening efficiency was investigated. The mode II interlaminar fracture toughness was tested and the fracture surface was examined by scanning electron microscope. The results showed that the interlaminar structure was closely related with the interlayer structure and the synergistic toughening effect depended greatly on the hybrid structure. [ABSTRACT FROM AUTHOR]

In this study, the water hyacinth was used as a reinforcement of green composites. The chemicals for treatment of water hyacinth are solutions of alkaline, soap and water to determine water absorption. The chemical treated process of the water hyacinth fibers ha d important influences t o the chemical structures and mechanical properties of the green composites. Micrographs analyses of scanning electron microscope (SEM) show obviously roughness of fiber surface after the ch emical tr eatment as we ll as ar rangement of st ructures among the water hyacinth fibers. Similarly, the results of analysis by Fourier transform infrared spectroscopy (FT-IR) showed that most of the intensity of the absorbed peaks was decreased markedly at the wavenumbers of 1375 cm-1 and 1542 cm-1. These a r e r e lated t o lignin extraction with alkaline solution, effectively. In particular, the compressive strength of the water hyacinth/roving composite has high value approximately to that of fiberglass composites (unfriendly composites). The water hyacinth/roving composites have significantly improvements in flexural and compressive strengths and this proves that the environmentally friendly composite responded to high requirements for various applications. [ABSTRACT FROM AUTHOR]

The present work aims to investigate the effect of nanofiller, lead oxide on the mechanical, thermal, and water intake behavior of luffa fiber-reinforced epoxy polymer matrix composites. Filler material PbO of 20 nm was added in different weight proportions along with luffa fiber to the matrix and the compression molding technique was used for the fabrication of the composite laminates. Tensile, flexural, and impact properties were studied on the prepared samples. The influence of lead oxide on glass transient temperature (Tg) and the curing of epoxy were also studied using the Differential scanning calorimeter. The optimum mechanical and thermal properties were observed on the addition of 1.25 wt. % of nanofiller. The morphological images show various defects like interfacial behavior, fiber pulls outs, voids, and internal cracks, and these were examined using a scanning electron microscope. Hence the present investigation showed that the addition of nanofiller could enhance the mechanical strength of the natural fiber composite. Further, it enhanced the moisture resistance and thus could find potential structural and packaging applications. [ABSTRACT FROM AUTHOR]

Magnesium oxychloride cement (MOC) as a green cement has superior mechanical properties such as high strength and quick gain of early strength, however the inherent brittleness has limited its applications where ductility is crucial. To enhance the strength and ductility, a novel hybrid fibre-reinforced MOC-based composite (FRMOC) is developed for the first time using polyethylene (PE) fibres and basalt fibres (BF) to reinforce the MOC. A systematic investigation of the effect of fibre dosage on the flowability, rheological properties, compressive strength, and tensile properties of the developed FRMOC is conducted in this study. The results revealed that the addition of fibre reduces flowability while increasing the yield stress and plastic viscosity. The 1-day compressive strength of the FRMOC reached 68.2–85.4% of the corresponding value at 28 days, demonstrating its high early strength characteristic. The mix with 1.25% PE and 0.75% BF exhibited the maximum compressive strength at all curing ages. All the mixes consistently demonstrated excellent tensile strength and tensile strain capability (ductility), with the tensile strength and tensile strain capacity of 10.95 MPa and 4.41% achieved for the mix of 2% PE fibre, and 8.49 MPa and 2.43% for the mix of 1.25% PE and 0.75% BF respectively. Moreover, a decline in strength characteristics and strain capacity was observed as BF percentages increased. Scanning electron microscope (SEM) analysis was further employed to investigate the morphological changes in the FRMOC matrix at the microscale to discover the fibre reinforcing mechanism. • Hybrid fibre reinforced MOC (FRMOC) with enhanced strength and ductility is developed. • FRMOC demonstrates high-early-strength characteristic. • Rheological, physical, and mechanical properties were evaluated. • 1.25% PE and 0.75% BF-reinforced FRMOC exhibited maximum tensile strength and strain capacity. • Microstructural analysis is performed to analyse the morphological alterations. [ABSTRACT FROM AUTHOR]

This study investigates the physical and mechanical properties of short Entada mannii- glass fiber polypropylene hybrid composites. The polymeric hybrid composite was produced by combining different ratios of Entada mannii fiber (EMF)/glass fiber (GF) using the compression molding technique. The tensile properties, compressive strength, impact strength and hardness were evaluated while the fracture surface morphology was examined using the scanning electron microscope (SEM). It further evaluates the moisture absorption and percentage void content of the developed composites. The experimental results show that tensile, compressive, impact and hardness properties of all the hybrid composites were significantly improved as compared with single reinforced composites. Specifically, hybrid composites (EMF/GF5) revealed an overall tensile strength of 41%, hardness of 51% and compressive strength of 47% relative to single reinforced composites, which can be ascribed to enhanced fiber–matrix bonding. The chemical treatment enhanced the EMF fiber surface and promoted good adhesion with the polypropylene (PP) matrix. Moisture absorption properties revealed that the addition of EMF/GF reduces the amount of moisture intake of the hybrid composites attributed to good cementing of the fiber–matrix interface. Morphological analysis revealed that single reinforced composites (EMF1 and GF2) were characterized by fiber pullout and deposition of voids in the composite as compared with the hybrid composites. [ABSTRACT FROM AUTHOR]

Hybrid laminates made using natural fibers have been finding applications in diverse fields such as automotive parts, building structures and sports goods. These laminates incorporate the benefits of the reinforcements used in constructions. The present work deals with the fabrication of hybrid laminate comprising of the natural fibers areca and kenaf in varying stacking sequences through the hand layup method. Epoxy resin (LY556) and hardener (HY951) are mixed in the ratio of 10:1 to prepare the matrix material. Six different hybrid laminates having five layers of areca and kenaf in different stacking sequences are produced. Two more laminates having either kenaf or areca in all the five layers and are produced to act as reference laminate. The prepared laminates are cut as per ASTM standards and subjected to tensile, compressive, flexural, impact and hardness tests in order to identify the properties of the fabricated laminates. The result shows that composite made with kenaf fiber as skin material and areca as core materials exhibit better tensile, flexural and hardness properties. Likewise, composites with outer layers of areca and core layers of kenaf fibers have high compressive and impact strength. The fractured surfaces after the mechanical tests are investigated through the Scanning Electron Microscope (SEM). [ABSTRACT FROM AUTHOR]

This article investigates the effect of fabrication techniques on the physical, mechanical, and erosion wear properties of glass fiber reinforced dolomite dust‐filled epoxy composites. The composites were fabricated by hand layup and vacuum‐assisted resin transfer molding (VRTM) techniques with fixed glass fiber (20 wt%) and varying dolomite dust (0 to 15 wt%) with epoxy resin. In physical properties, the experimental density consistently increased with the increase in the dolomite hand layup and the VRTM process; in opposite the voids content increased in the hand layup process and decreased in the VRTM process. In mechanical properties, the hardness, impact energy, and interlaminar shear strength increases while tensile and flexural strength consistently decreases with dolomite dust content. Using Taguchi's optimization technique, the erosion wear of the fabricated composites was also evaluated at different impingement angles, impact velocities, and erodent sizes. Erosion test results indicate that the VRTM process fabricated composite has minimum erosion wear compared to the hand layup process. The eroded surfaces were studied using a scanning electron microscope to understand the erosion behavior of particulate‐filled fiber reinforced polymer composites. [ABSTRACT FROM AUTHOR]

In this work, a comparative assessment of the mechanical properties of chopped glass-carbon-aramid fiber reinforced polypropylene (PP) composites was carried out. Reinforcement and matrix materials were mixed with the extrusion method, and then composite materials were produced in the form of plates with the press molding technique. The composites' tensile, 3-point bending, and drop weight tests were carried out and the surface morphology of the fractured surfaces was examined by Scanning Electron Microscope (SEM). The tests' results indicate that the mechanical properties increase significantly in the presence of fiber. On the other hand, it is observed that the effect in percentage decreases as the fiber content increases. Moreover, It was observed that some of the fiber materials were pulled out from the matrix as a result of stress. ANOVA analysis using S/N values, and F-Test were performed to observe the effectiveness of each test factor (fiber type, and fiber additive content) on the test results. Finally, an optimization study was carried out to obtain the mathematical expression by fitting the experimental data. [ABSTRACT FROM AUTHOR]

Epoxy matrix composites owing to their outstanding properties such as high strength, low weight, high thermal stability and good stiffness are broadly utilized in various industries. Also, the basalt fibers as a green industrial material show various extraordinary properties such as high mechanical strength, desired stability, suitable chemical resistance, and high temperature resistance. In this study, the effect of silane-modified nanozirconia on the tensile and flexural properties of basalt fibers/epoxy composites is investigated. As a first step, the surface of nanozirconia was modified with a silane coupling agent namely 3-methoxysilyl propyl amine. Fourier transform infrared (FT-IR) spectroscopy has been used to demonstrate the chemical nature of the silanized ZrO2 nanoparticles prepared. 3-methoxy silyl propyl amine/nanozirconia with various loadings (0, 1, 3 and 5 wt.%) were added to the epoxy resin via mechanical and ultrasonication routes. The resultant mixtures were then utilized to fabricate ZrO2/satin texture basalt fibers/epoxy nanocomposites using hand-layup technique. This symptomatic behavior exposes the successful modified ZrO2 nanoparticles to enhance the interfacial bonding. Also, a scanning electron microscope (SEM) was used to study the distribution level of silanized ZrO2 nanoparticles in the matrix as well as the fracture surfaces of the specimens. Experimental results from three-point bending and tensile tests showed that with the dispersion of 3 wt.% nanozirconia, flexural strength, flexural modulus, flexural failure strain, tensile strength, tensile modulus and tensile failure strain enhanced by 90, 74, 84, 76, 85 and 14%, respectively, compared with specimens without nanozirconia. The SEM observations of the fracture surfaces of the nanocomposites clearly indicated that the enhancement in the flexural and tensile properties was due to the improvement in the interfacial adhesion between the basalt fibers and modified ZrO2 nanoparticles-enhanced epoxy matrix. [ABSTRACT FROM AUTHOR]

High‐performance composites reinforced with natural fibers are next‐generation structural materials due to their recyclability and light weight. Manufacturing composites with high strength has been a challenge. Here, we describe the manufacture of novel composites reinforced with wood fibers using densification by hot‐pressing and fixing by curing reaction with phenolic resin. This composite with 1.4 g/cm3 had high mechanical properties, high water stability, and aging‐resistance, and exhibited a flexural strength and internal bonding strength of 102.4 and 7.5 MPa, respectively. The strength and modulus are 1.5–6.0 and 1.3–28.1 times higher than those of most of the wood fibers reinforced composites. After immersing in water for 24 h, the water absorption and thickness swelling are only 1.3% and 0.8%, respectively. Scanning electron microscope characterization indicates that the cell wall is totally collapsed and became complete densification. And the collapsed cells are fixed by phenolic resin. This production strategy for the composites was shown to be universally effective for various species of natural fibers. These novel wood fiber‐reinforced composites were suitable for commercial manufacture in the current production line, making them a low cost and high‐performance alternative to automotive and aerospace industries. [ABSTRACT FROM AUTHOR]

Mechanical properties of vinyl ester hybrid composites reinforced with alkali treated Smilax zeylanica and sisal fibers were studied at wet condition in the present communication. Hybrid composites were fabricated by using a simple hand lay up technique based on three different fiber loading of 25, 35, and 45 wt.% with alkali treated fibers. Hybrid composite specimens were then subjected to the water absorption test to observe the behaviours of composite specimens at wet condition under mechanical loads such as tensile, flexural and impact. The water absorption test was carried out in two ways in the distilled water environment at room temperature. The first way test was conducted for 10 days to observe the percentage of water particle absorption of hybrid composites. The second way test was performed for 5 days to determine the mechanical properties of hybrid composites at wet condition to observe its durability when they are used in outdoor applications. Mechanical properties of hybrid composite specimens at wet conditions were compared with the dry composite specimens. Experimental results showed that the percentage of the water particle absorption in the alkali treated hybrid fiber composites is lower as compared to the untreated hybrid fiber composites. Mechanical properties of alkali treated hybrid fiber composites at wet condition are slightly reduced as compared to the treated hybrid fiber composite at dry condition. As a result, it is observed that the resistance to the penetration of the water particles is higher for the alkali treated smilax zeylanica and sisal fibers reinforced vinyl ester hybrid composites. The fracture surfaces of the hybrid composite specimens were examined by scanning electron microscope to understand the effects of water absorption on the mechanical properties. [ABSTRACT FROM AUTHOR]

High performance carbon nanotube (CNT) nanopaper (NP) reinforced polyurethane (PU) nanocomposite coating with high potential for aerospace and automotive applications was successfully fabricated and evaluated in this work. Different PU formulations were used to fabricate nanocomposites to study the effect of hard segment content on resin infiltration and nanocomposite mechanical properties. The process window of PU infiltration into the CNT NP was established by rheology measurements and thermal gravimetric analysis (TGA). The micro‐structure morphology of the nanocomposite was characterized by scanning electron microscope (SEM). Uniform CNT distribution in PU matrix was observed in the high‐resolution SEM images, which indicated good resin impregnation quality. Based on mechanical properties and process window, a PU formulation was selected as matrix to fabricate NP/PU nanocomposite coating for carbon fiber/epoxy composites (CFPC) substrate. The flexural strength and impact resistance of the CFPC were significantly improved by 9% and 14.7% after applying the NP/PU nanocomposite coating. Aimed at industrial applications, a continuous nanopaper fabrication process was successfully demonstrated in this work. Through the process window study, a continuous process to fabricate nanocomposite is proposed for future scale‐up. [ABSTRACT FROM AUTHOR]

High water absorption capacity and low biodegradation of fiber reinforced composites are the major drawbacks, which limit their applications in different sectors. Development of composites with complete biodegradability is challenging as biodegradability may be incomplete by lowering of its water adsorption capacity. In this work, a series of thermoplastic starch (TPS) reinforced jute (10–40 wt%) composites were developed by compression molding and measured by their mechanical properties. The composite with 30% jute showed the maximum tensile strength (27.3 MPa). Contact angle, and water absorption measurements exposed that composites are moderately hydrophobic in nature. Both soil burial and fungal degradation testing showed biodegradability of composites. Characterizations of optimized composite before and after biodegradation test, were carried out by FTIR, SEM and optical microscope. The present study showed promise on feasible applications of jute-starch composites in packaging, automobile sector, cutlery, indoor furnishing, etc. as a substitute of plastic-based composites. [ABSTRACT FROM AUTHOR]

The primary purpose of this work is to study the fabrication of a flexible natural cellulosic fiber composite. In this respect, natural cellulosic fiber was obtained by modified poplar wood fiber through sodium hydroxide (NaOH) and γ-Aminopropyl Triethoxysilan. Then, the composites were fabricated by hot-pressing the modified wood fibers and polyurethane following characterization. Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM) observation results confirmed that some of the hemicellulose and lignin were removed from wood fibers after NaOH modification and successfully grafted with alkoxy structures after KH550 modification. NaOH&KH550 modification improved the interfacial compatibility between poplar wood fibers and polyurethane. The flexibility of the composites was improved (the slenderness value was reduced by 113 %), allowing flexible deformations such as bending, twisting, and knotting. In addition, thermal stability, tensile strength (increased by 105 %), elongation at the break (increased by 125 %), and water resistance were increased. This flexible natural cellulosic fiber composite is expected to be applied in the veneering of curved materials and special-shaped structure furniture, providing a theoretical basis for improving the added value of wood-based composites. [ABSTRACT FROM AUTHOR]

The surface topography and interface characteristics play a significant role in determining the mechanical properties of carbon fiber reinforced polymer (CFRP) composites. These features are primarily influenced by the surface chemical structures and their interactions with the matrix resin. Here, we developed a rigid-flexible coating consisting of polyetheramine (PEA) and polydopamine (PDA) on the fiber surface to control the interface and improve the mechanical properties of CFRPs. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectrum (FT-IR) results validated the successful introduction of polymeric chains and fiber surface characteristics including rough surfaces, slim polymer layers and uniform dots were examined by scanning electron microscope (SEM) and transmission electron microscopy (TEM). Contact angle tests indicate that the functionalized coating noticeably enhances the interaction force between carbon fibers, promoting improved wettability by the matrix resin. The bending and interlaminar shear strength of CFRP prepared by functional carbon fiber are increased by 45.76 % and 47.63 %, respectively. The drop weight impact (DWI) test confirms the positive effect of improved interfacial properties on the out-of-plane impact resistance of CFRPs. [Display omitted] [ABSTRACT FROM AUTHOR]

Polysulfone (PSU) is a widely used polymer in water purification membranes. However, its hydrophobicity hinders its practical application. Herein, the wettability of PSU has been improved by producing a coelectrospun fibrous composite membrane using a hydrophilic component, chitosan‐polyvinyl alcohol (CS‐PVA). First, different proportions of PVA and CS solutions were mixed and electrospun to prepare CS‐PVA blend fibers. Scanning electron microscope (SEM) observations revealed that CS‐PVA blend fibers with maximum CS content can be obtained in 30:70 CS:PVA weight ratio. The optimum CS‐PVA solution was subsequently used alongside PSU solution and were fed into two distinct syringes, which were then electrospun simultaneously at a constant voltage and distance of 15 kV and 15 cm, respectively. Different composite compositions of PSU/CS‐PVA were achieved using different feeding rates for each solution. Based on SEM images, the prepared composite fibers were beadless. The ultimate strength of the composite mats decreased by increasing the amount of CS‐PVA due to the significant difference in the fiber diameter of each component and the resulting stress concentration. However, the thermal stability of composite membranes remained almost the same as pure PSU fibers. Moreover, samples with higher CS‐PVA content showed better wettability and higher water flux. [ABSTRACT FROM AUTHOR]

A hybrid composite material was obtained by stacking carbon fiber reinforced plastic (CFRP) onto 7075‐W Al alloy sheet. Mechanical properties of the CFRP/Al hybrid composite material were measured by tensile and flexural tests. To investigate the flow of the epoxy, the thinning was measured using an optical microscope and the defects were observed by a scanning electron microscope. A finite element model was established to predict the thickness and the contact pressure distributions of the CFRP/Al hybrid composite material during the forming process. The results showed that the tensile strength (TS) of the CFRP/Al hybrid composite was increased by 10% and the fracture strain was increased by 24% compared with the single 7075 Al alloy. The flexural strength (FS) and the displacement of the loading nose were improved by 13% and 75%, respectively. According to the microstructure observation, large cracks in the epoxy could be found on the side wall of the U shape part. The results of numerical analysis indicated that the low contact pressure at side wall was the main reason for the decrease of the tensile and FS and the delamination between laminates. [ABSTRACT FROM AUTHOR]

Silicon carbon black (SiCB), a kind of biomass carbon material, is a kind of pyrolysis ash prepared by anoxic pyrolysis of rice husk. When filled as an inorganic reinforcement in the composite material basalt fiber (BF) reinforced polyamide 6 (PA6), it has synergetic effect with the POE‐g‐MAH elastomer. Differential scanning calorimetry analysis shows that KSiCB plays a role of heterogeneous nucleation in the composite material, accelerates the nucleation and crystallization speed of PA6, and can increase the strength and rigidity of the composite material. Scanning electron microscope observation of the fracture surface of the composite material shows that the addition of KSiCB can effectively "pin" and inhibit crack propagation. When the content of KSiCB is 2.5 phr, the tensile strength of the composite material KSiCB/POE‐g‐MAH/PA6(BF) reaches a maximum of 125.194 MPa, the tensile modulus is 2791.257 MPa, the bending strength reaches 192.034 MPa, and the impact toughness reaches 23.42 kJ/m2. [ABSTRACT FROM AUTHOR]

In this research, the effect of siliconized chitosan biopolymeric particles and morinda fiber in epoxy composite and their mechanical and machining behavior were studied. The primary aim of this research was to investigate how the silane‐treatment influences the surfaces of natural biopolymeric particle and fiber in epoxy composite and to study the mechanical and machining behavior. The chitosan and morinda fibers were surface‐treated using an amino silane 3‐Aminopropyltrimethoxylane (APTMS) via aqueous solution method. The composites were prepared using the hand lay‐up method followed by post‐curing at 120οC. The mechanical results showed that the silane surface‐treated chitosan and morinda natural fiber‐reinforced epoxy composite gives improved tensile, flexural and impact results of 148 MPa, 163Mpa and 6.9 J respectively. The inter‐laminar shear strength of silane‐treated morinda fiber gave the highest value of 28 MPa. Similarly, in the drilling process, the surface‐treated reinforcements showed the highest adhesion with matrix without any delamination. The drilled hole dimension stability at the top and the bottom surface was significantly high for silane‐treated epoxy composites. The scanning electron microscope images revealed high adhesion of fiber and uniform dispersion of chitosan particle in the epoxy matrix. Hence, this study confirms that silane surface‐treatment is an essential process while making high‐performance natural composites for various engineering applications. [ABSTRACT FROM AUTHOR]

Applicability of natural fiber-reinforced composites in automobile, aerospace like sectors has been increasing as more number of research works is concentrating on natural fibers owing to their eco-friendly nature. Biodegradability of natural fibers is main advantage of them over artificial fibers. Natural fiber-reinforced composite possesses good thermal and mechanical properties besides other requirements. For this reason, investigation of one such natural fiber-reinforced composites has been the focus of the present study. In the present work, composites made up of abutilon indicum fiber reinforced with epoxy have been prepared. Mechanical, morphological, thermal, and spectroscopic studies on the test specimens prepared using the above composites were carried out to evaluate their respective strengths. Also, the effect of alkali treatment (NaOH) for the fibers was studied and evaluated. Scanning electron microscope results indicated that the composite made up of alkali-treated fibers possessed better mechanical properties. Using differential thermal analysis–thermogravimetric analysis apparatus thermal behavior of the composites and using Fourier transform infrared spectroscopic studies, the presence of function groups like C–O, C–H was determined. Thus, characterization of abutilon indicum fiber-reinforced epoxy composites has been carried and properties are evaluated for their applicability to automotive, aerospace similar industries. [ABSTRACT FROM AUTHOR]

Polymer composites have good mechanical, friction, durability, and wear performance after being reinforced with waste or nanofiller. These features make them flexible in many structural applications. This study was carried out to improve the mechanical performance of polymer composites using silica-based, waste, and nanomaterials. To achieve this, marble dust of millimeter size, silica fume of micrometer size, and Nano-SiO2 of nanometer size were added separately or in combination to the polymer matrix. The samples were tested to obtain the compressive strength, tensile strength, ultrasonic pulse wave velocity, dynamic modulus of elasticity, toughness, and density of reinforced polymer composites. The results of the tests on the polymer composites indicated that the best ratios were 30%, 5% and 1% for separately added marble dust, silica fume and nano-silica groups, respectively, while the contribution of nano-silica to marble dust/silica fume was the optimum when added by 1%. Moreover, the results showed that adding marble dust to polymer composites increased ductility while adding silica fume and nano-silica reduced the ductility of the samples. Additionally, the microstructural properties of the polymer composites with waste marble dust and silica fume, and nano-SiO2 additives were evaluated using a scanning electron microscope (SEM) to provide a close relationship between the morphological structure and mechanical properties. This study opens up a new way for added value using waste materials like marble dust/silica fume as well as nanomaterials in polymer composite applications. [ABSTRACT FROM AUTHOR]

Usage of composites with natural fiber reinforcement is drastically increasing in recent times because of their low density, biodegradable nature, and low cost. However, natural fibers have certain core problems such as poor adhesion between the fiber and matrix and a relatively high degree of moisture absorption. Alkaline treatment of natural fibers is aimed at improving the adhesive strength so that effective stress transferability takes place in the composite. In the present work, Cordia-Dichotoma fibers were treated with sodium hydroxide (NaOH) and composites were prepared with different weight ratios of these fibers reinforced with epoxy. The prepared composites were tested for their tensile and flexural strengths (mechanical properties). Besides, for a comprehensive material characterization, IR spectroscopy (FT-IR), scanning electron microscope, and thermogravimetric analysis were carried out. This work investigates the influence of aforementioned NaOH treatment on thermal, mechanical, and morphological properties of the composite material. [ABSTRACT FROM AUTHOR]

The tensile, flexural, and morphological properties of Napier fiber reinforced nanomodified epoxy composites were investigated. Untreated and alkali‐treated Napier fibers, as well as nanoclay and epoxy resin, were used to fabricate Napier fiber reinforced nanomodified epoxy composites by using cold press compression machines. Napier fiber was treated with 5% dilute sodium hydroxide (NaOH) solution for 6 h. Varying amounts of nanoclay filler (3, 5, and 10 wt%) were mixed with the epoxy resin prior to fabricating the Napier fiber reinforced nanomodified epoxy composites. The results of mechanical testing indicated that the alkali‐treated Napier fiber reinforced nanomodified epoxy composites incorporating 5 wt% nanoclay exhibited the highest flexural and tensile properties. Morphological analysis was then conducted to further analyze the fractured specimens following the mechanical tests. The scanning electron microscope images of the Napier fiber reinforced nanomodified epoxy composites that contained 5 wt% nanoclay revealed good interfacial bonding between the matrix and the reinforcement. [ABSTRACT FROM AUTHOR]

• Tetraethylorthosilicate sol-gel and silane combination treatment is used. • The reinforcing effect of fibers in composites is improved. • Combination treatment shows the highest interfacial shear strength. • Thermal properties of the modified fiber composites are improved. In order to prepare high performance sisal fiber reinforced polypropylene composites, this paper pays special attention to the changes of intrinsic mechanical properties of the sisal fiber so as to achieve the maximum reinforcing effect of the fiber. For achieving this aim, the sisal fibers were modified by tetraethylorthosilicate (TEOS) sol-gel method to form SiO 2 -based organic-inorganic hybrid materials. For a better result, a novel combined modification method by TEOS precursor solution and γ-aminopropyltriethoxysilane solution for the fibers was put forward and performed. Then the relevant mechanism was also analyzed in detail. The corresponding composites were prepared by melt blending with polypropylene matrix and polypropylene-graft-maleic anhydride (MAPP) compatibilizer, and the interfacial and mechanical properties of composites were studied by single fiber fragmentation test and mechanical test, respectively. The results show that the mechanical and thermal properties of the modified fiber composites are improved compared with the untreated fiber composite. The combined modification composite presents the highest interfacial shear strength, which increases by 259.49% compared with the untreated fiber composite. A good interfacial bonding is obviously observed in the combined modification composite by the analysis of scanning electron microscope (SEM). The tensile strength and modulus of the composite with the combined treatment (20 wt% fiber loading) increase by 21.72% and 28.18%; the flexural strength and modulus increase by 3.61% and 16.02%; and the impact strength increases by 21.28%. [ABSTRACT FROM AUTHOR]

In the last decade, natural plant fibers (jute, sisal, coir, banana, hemp, kenaf, flax, etc.) are getting attention from many researchers and academicians to utilize it as an alternate reinforcement of synthetic fiber reinforced polymer composites. These fibers are becoming a great replacement of conventional fibers (such as glass, carbon, and aramid) due to their light weight, low cost, carbon neutrality, fairly good mechanical properties, high specific strength, and biodegradability characteristics. Some chemical treatments are required to enhance the fiber matrix interfacial strength and to minimize the moisture absorption by these fibers which would ultimately improve physico-mechanical properties of these fiber reinforced composites. This paper is a review on mechanical properties of the natural plant fiber reinforced polymer composites and various factors affecting the mechanical performance of it. The tribological behavior of natural fiber reinforced polymer composites and scanning electron microscope analysis are also discussed. Some mathematical models are mentioned which are useful to predict mechanical behavior of the composites. It is found that Halpin–Tsai equation is the most effective equation amongst others in predicting Young's modulus for short-fiber reinforced composites with minimum error. The applications of natural plant fiber reinforced polymer composites in various engineering fields are discussed. [ABSTRACT FROM AUTHOR]

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The aim of this paper is to present research findings on the measurements of mechanical, morphological, and thermal properties of Roselle fiber-reinforced thermoplastic polyurethane composites. The Roselle fiber/thermoplastic polyurethane composites were prepared with fibers of different sizes such as 125 µm and lower, 125–300 and 300–425 µm by internal mixer and hot press at 170°C. The results show that mechanical properties (tensile, flexural, and impact properties) of the composites were improved with the increase in fiber sizes. The highest tensile (10.45 MPa), flexural strength (6.93 MPa), and impact strength (20.22 kJ/m2) was obtained from composites with 300–425 µm fiber size of Roselle fiber/thermoplastic polyurethane composites. Morphological properties of dispersion fiber and tensile fracture surfaces were studied using scanning electron microscope. Thermal properties of the composites were studied using thermogravimetric analyses and results showed that the thermal decomposition effect was almost similar for all compositions. [ABSTRACT FROM PUBLISHER]