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This research paper presents a comparative experimental study on the impact of zinc oxide and zirconium dioxide nanomaterials on the chemical, mechanical, and crystalline properties of epoxy resin (diglycidyl ether of bisphenol-A). Nanomaterials were incorporated into the epoxy resin at three different concentrations (4%, 6%, and 8%) by weight. Results indicated enhanced properties of the epoxy resin, including tensile and compressive strengths, as well as improvements in chemical and crystalline characteristics, assessed through scanning electron microscope (SEM) and Fouriertransform infrared spectroscopy (FTIR). Notably, zirconium dioxide exhibited superior performance across all properties, enhancing tensile and compressive strengths by 67% and 50%, respectively. Zinc oxide, at the same concentrations, led to a 50% increase in tensile strength and a 40% increase in compressive strength. These outcomes were observed at the highest concentration (8%wt) of both nanomaterials and the pure epoxy resin. The presence of nanomaterials at this ratio promoted greater cohesion within the composite, as evidenced by SEM images of selected samples. SEM analysis highlighted the pivotal role of ZrO2 nanoparticles in improving epoxy integration, surface quality, crystallization, and imperfection removal, crucial factors for enhancing composite materials. FTIR analysis of the resin containing ZrO2 nanoparticles revealed shifts and alterations in peaks, indicating successful nanoparticle-epoxy interaction, resulting in notable structural changes. [ABSTRACT FROM AUTHOR]

Reactive polyimide (PI) containing phenolic hydroxyl groups was prepared by the polymerization of 2,2-bis(3-amino-4-hydroxyphenyl) hexafluoropropane and mixed thiodiphthalic anhydride. A series of epoxy resin composites were obtained by adding reactive PI to N,N,N′,N′ -tetraglycidyl-4,4′-diamino-diphenylmethane (TGDDM) epoxy resin in different proportions. The effect of PI content on curing behavior, thermal properties, and mechanical properties was carefully investigated. Even a small amount of PI addition improved the mechanical properties and heat resistance of the epoxy resin, particularly the fracture toughness. Among them, epoxy resin composites EP-PI-1.5 with the addition of 1.5 wt% PI showed the best mechanical properties, whose impact strength, fracture toughness, and tensile strength were increased by 114%, 59%, and 34%, respectively. The phase morphology was also investigated to illustrate the fracture mechanism by scanning electron microscope (SEM) characterization. [ABSTRACT FROM AUTHOR]

In this study, we investigated how the chemical structural properties, mechanical properties, and morphology of large‐size graphene platelets (LGPs) doped glass fabric (GF)/epoxy composites are affected by varying loading amounts of LGPs. Scanning electron microscope results revealed that the dispersion and filling effect of LGPs can improve the flowability of the resin, reducing the aggregation and shrinkage of the resin on the glass fabric surface, thereby facilitating better resin infiltration and coverage of the glass fabric surface. From the spectrum analysis, the binding of LGPs with epoxy resin was the physical combination, without new chemical groups generated during the curing process. The addition of LGPs improved the ratio of the crystalline phases in the composites, from 30.00% of the GF/epoxy to 57.50% of the GF/epoxy@2.2LGPs. Mechanical properties indicated that the composites exhibited greater tensile strength than pure GF, which progressively increased with increasing LGPs content until it reached 1.5 wt%, then the tensile strength starts to decrease. And the GF/epoxy@1.5 LGPs exhibited 136% enhancement in tensile strength compared to other carbon fillers reinforced composites, which achieved a satisfactory enhancement under relatively low loading content. Highlights: The effect of the large‐size graphene platelets (LGPs) on the properties of glass fabric (GF)/epoxy composites.Compared to the glass fabric/epoxy composite, the LGPs doped composite possessed a much higher storage modulus (E′).The LGPs doped composite exhibited 136% enhancement in tensile strength compared to other carbon fillers reinforced composites.The addition of LGPs improved the ratio of the crystalline phases in the composites. [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]

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 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]

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]

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]

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]

Cost-effective bamboo strip composite materials have been developed with the low energy consumption, excellent product quality, and high utilization rate, due to the refinement, homogenization, and standardization of bamboo strip. However, there is the low interface compatibility between polar hydroxyl groups on the surface of bamboo strips and non-polar resin matrix. The purpose of this study is to fabricate the structural or sub structural bamboo strips composite materials. The alkali solution was used to treat the bamboo strips for the penetration of resin on the interface and the mechanical properties of composite materials. A systematic investigation was made to clarify the effect of NaOH alkali treatment concentration on the properties of bamboo strips and the epoxy resin composites. The bamboo strips were used as the reinforcement phase, whereas, the epoxy resin as matrix phase. The composites with an average content of 75% bamboo strips were then prepared by hot pressing. Four concentration gradients of NaOH solution were set in the treatment. The properties of bamboo strips and their epoxy resin composites were characterized by means of Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscope (SEM), Thermogravimetric Analysis (TG), and Dynamic Mechanical Analysis (DMA). The experimental results showed that the alkali treatment efficiently removed some impurities, such as lignin, hemicellulose, and wax on the surface of bamboo strips, further to enhance the tensile strength and thermal stability of bamboo strips. SEM results show that the surface fiber morphology of bamboo strips tended to be regular after the proper alkali treatment. Specifically, the fine and smooth microstructure was conducive to the resin penetration. The polarity of bamboo strips first increased and then decreased with the increase of NaOH solution concentration. The crystallinity increased from 60.0% to 63.6% after treatment. The TG analysis demonstrated that there were the lower end degradation temperature of alkali treated bamboo strips, and the lower maximum decomposition rate, indicating the better performance of thermal decomposition. More importantly, the best properties were achieved at the concentration of NaOH solution of 2%, including the tensile property of bamboo strips, the interfacial bonding property with the epoxy resin, and the shear strength. Specifically, the tensile strength of bamboo strips, the shear strength of the composites increased by 52.11%, and 55.24%, respectively. The DMA test results showed that the bamboo strip/epoxy resin composites after the alkali treatment presented the better structural stability under dynamic load in the single frequency (1 Hz) test condition in the range of 30-90 ℃. Once the concentration was 2%, the maximum storage modulus of the bamboo strip/epoxy resin composite was 1.3 times that of the untreated. There was no outstanding difference of storage modulus before and after treatment in the range of 9-140 ℃. A downward trend was found in the loss modulus and loss factor of the composites after alkali treatment in the range of 60-140 ℃. Consequently, the alkali treatment can be expected to enhance the thermal stability and tensile strength of bamboo strips. The interface strength between bamboo strips and epoxy resin was improved, together with the static and dynamic mechanics of bamboo strips reinforced epoxy resin composite resin. The improved composites can also be used in the outdoor agricultural engineering, buildings, and outdoor gardens, in order to reduce the production cost and the comprehensive utilization rate of bamboo strips. [ABSTRACT FROM AUTHOR]

Purpose: Bismaleimide (BMI) is a kind of thermosetting resin and its application is usually limited by low toughness. In this paper, two kinds of reinforcement intercalator amino-terminated polyoxypropylene (POP) and octadecyl trimethyl ammonium chloride (OTAC) were designed and synthesized to toughen BMI resin and the toughening effect was compared and analyzed. The purpose of this paper is to toughen BMI resin and analyze the toughening effect of two reinforcements intercalator amino-terminated polyoxypropylene (POP) and octadecyl trimethyl ammonium chloride (OTAC). Design/methodology/approach: Sodium-based montmorillonite (Na-MMT) was modified by POP and OTAC, and the ion-exchange reaction obtained organic montmorillonite (POP-MMT and OTAC-MMT). The polymer matrix (MBAE) was synthesized, in which 4,4'-diamino diphenyl methane BMI was used as the monomer and 3,3'-diallyl bisphenol A and bisphenol A diallyl ether were used as active diluents. And then, POP-MMT/MBAE and OTAC-MMT/MBAE composites were prepared using MBAE as matrix and POP-MMT or OTAC-MMT as reinforcement. The Fourier-transform infrared, X-ray diffraction and scanning electron microscope (SEM) of the filler and microstructure and mechanical properties of the composite were characterized to the better reinforcement. Findings: POP-MMT and OTAC-MMT enhanced BMI-cured products' toughness by generating microcracks in the polymer to absorb more fracture energy. Meanwhile, POP-MMT and OTAC-MMT were the main stress components and the enhancement of the interface interaction was beneficial to transfer the external force from the matrix to the reinforcement and improved the mechanical properties of the composite. Furthermore, with the intercalation rate increasing, the compatibility of the two phases was increased and the performance of MBAE was also elevated. Research limitations/implications: BMI is generally used as aerospace structural materials, functional materials, impregnating paint and other fields. However, high crosslinking density leads to moulding material's brittleness and limits a wider range of applications. Therefore, it has become an urgent priority to explore and improve the mechanical properties of BMI resin. Originality/value: POP and OTAC have successfully intercalated Na-MMT layers to get POP-MMT and OTAC-MMT, and the interplanar crystal spacing and the intercalation rate were calculated, respectively. The results were corresponding with the SEM images of POP-MMT and OTAC-MMT. After that, the morphology of composites illustrated the compatibility was related to the intercalation rate. According to the mechanism of modified MMT toughening epoxy resin, when they were dispersed uniformly in the matrix, the composite's mechanical properties had been significantly improved. Additionally, OTAC-MMT with a higher intercalation rate had better compatibility and interfacial force with the matrix, so that the mechanical properties of OTAC-MMT/MBAE were the best. [ABSTRACT FROM AUTHOR]

Kota stone dust (KSD) and fly ash (FA) are the wastes generated from the construction industry and thermal power plant, respectively. In the present work, a novel hybrid composite is developed to utilize KSD and FA as reinforcing phases in the epoxy matrix. The hand lay‐up method is adopted for the fabrication of 12 sets of samples. Four sets are prepared with single filler KSD and eight samples are prepared with a hybrid combination of KSD and FA. The prepared samples are undergone physical and mechanical tests. To understand the compatibility between filler‐matrix and visualize the dispersion of fillers in epoxy, micrographs are taken using the scanning electron microscope. The density and void contents of the material increases with an increase in filler content. The maximum water absorption measured is 0.96% for the combination of epoxy with 40 wt% KSD and 10 wt% FA. From mechanical testing, maximum tensile strength and flexural strength obtained is 34.4 MPa and 65.4 MPa, respectively, for a combination of epoxy with 20 wt% KSD and 5 wt% FA. Compressive strength and hardness increase with either of the content of the filler and reaches 116.28 MPa and 104 Shore D number, respectively, with 40 wt% KSD and 10 wt% FA. From experimentation, it was found that mechanical properties of the hybrid composites are better as compared to that of single filler composites though physical properties are slightly compromised by hybridization of fillers. [ABSTRACT FROM AUTHOR]

In the present work, the composite materials were prepared from coconut shell powder, palm kernel powder, and epoxy resin. The addition of coconut shell powder was considered when preparing the composite samples, and mechanical properties such as tensile strength, hardness, impact, bending strength, physical behavior water absorption, as well as morphological tests, were conducted using Fourier Transform Infrared Spectroscopy, Scanning Electron Microscope, and Thermogravimetric Analysis for both the prepared composite material boards and chipboard. The minimal variation of tensile stress and percentage of elongation between the 50 % coconut shell powder composite material and the wooden chipboard material is 4,44 MPa and 1,00 %, respectively, according to the findings of experimental tests.The lowest compressive stress and hardness variations between coconut shell powder composite material and wooden chipboard are found to be 0,14 MPa and 3,2 MPa, respectively. It is determined that the composite materials made from waste shell powders and epoxy resin are suitable for applications such as panel boards, automotive interior dashboards, roof sheets, and doors. [ABSTRACT FROM AUTHOR]

To improve the low-temperature toughness of epoxy resins, in this study, an epoxy-terminated hyperbranched polysiloxane (EPTS-12) was synthesized and introduced into the epoxy resin as a toughener. The structure of EPTS-12 was characterized by Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance (1H NMR), and the fractured surfaces of the modified resins were observed by a scanning electron microscope (SEM). With the content of EPTS-12 at 5 wt%, under room temperature (RT) and − 72 °C, the maximum values of elongation at break were 14.19% and 16.06%, increasing by 35.66% and 74.19% respectively. The test results of dynamic mechanical analysis (DMA) also showed that the toughness of the modified epoxy resins was improved. The SEM images of the fractured surfaces of the modified resins were used to investigate the toughening mechanism of the toughener (EPTS-12). With the virtue of a simple synthesis process, low cost, and good reproducibility, this toughener can further expand the application of epoxy resins. [Display omitted] • With 5phr EPTS-12, under RT and − 72 °C, the elongation values were increased by 35.66% and 74.19% respectively. • The dynamic thermomechanical behaviors of the composites were investigated via dynamic mechanical analysis (DMA). • The working mechanism of the toughener was studied by SEM images of the fractured surfaces. • These research results can provide a reference for the design and development of epoxy tougheners. [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]

Additive manufacturing technology can help us to produce complex components/parts easily. It can be used to develop the parts with multi‐material structures consisting of thermoplastic, thermosetting plastic, and ceramic fibers. This multi‐material structure enhances the performance of lightweight polymer‐based components. In this research work, poly‐lactic acid (PLA) lattice (mono‐material structure), PLA lattice filled with epoxy (bi‐material structure), and PLA lattice incorporated with embedded milled glass fibers (MGFs) in an epoxy matrix (tri‐material structure, TMS) were designed and developed by fused filament fabrication and solution casting methods. PLA lattice of 50% volume was fixed in all structures and 50% volume was filled with epoxy and MGFs. The dispersed MGFs in epoxy matrix were varied from 0, 2.5, 5, and 7.5 vol%. The mechanical properties were carried out by compression test, three‐point bending test, and tensile test. The results revealed that 5 vol% of MGFs in the epoxy sample (TMS) exhibited improved mechanical performances compared to other samples. The cone‐beam CT scan results confirmed the voids/porous free surfaces in the developed materials. The high‐resolution scanning electron microscope microstructural evolutions in‐terms of topography and fractured regions were also examined and reported. [ABSTRACT FROM AUTHOR]

This research work investigates the influence of hybrid particulate fillers, Mg–Al layered double hydroxide (LDH), and nanoclay (NC), on the mechanical properties and formability of glass laminate AA5052 epoxy composites (GLARE). The composite laminates were prepared by varying the weight percentage (i.e., 3, 4, and 5 wt%) of the hybrid fillers in the epoxy resin. The conventional hand layup technique was utilized for the fabrication of the laminates. The tensile test samples were prepared in different orientations with respect to the rolling direction (i.e., 0°, 45°, and 90°) to address their anisotropic nature. The flexural, impact, lap shear, and formability tests were conducted as per ASTM and IS standards. The Erichsen cupping test was performed to study the formability of the composite laminates. For each test, the results were compared with that of the laminates containing individual LDH filler, NC filler, and no filler material. The results showed that the composite laminate with 5 wt% of LDH + NC hybrid filler exhibited enhanced tensile properties, impact energy, and lap shear strength while the laminate of 4 wt% LDH + NC filler possessed better flexural properties. The formability of the composite laminates with hybrid LDH + NC fillers was observed to be lower than that of the laminates with individual filler materials and laminate without any filler. The variation observed in the test results was justified by investigating the failure mechanism of the composite laminates using a scanning electron microscope. [ABSTRACT FROM AUTHOR]

The aim of this research is to investigate the thickness influence on the efficiency of multiwalled carbon nanotubes (MWCNTs) in glass/epoxy composite laminates under the high‐velocity impact. Combining 0.25 wt% of MWCNTs in the 4‐layer and 8‐layer specimens and 0.1 wt% of MWCNTs in the 16‐layer specimen led to the maximum rise in the energy absorption and specific perforation energy compared with the unreinforced laminates. The significant growth in energy absorption in the 4‐layer, 8‐layer, and 16‐layer specimens was 5.8, 8.3, and 14.4 J, respectively. The number of agglomerations (dislocations) in the matrix was consequently increased as a function of thickness, which led to the better performance of MWCNTs with lower weight percentages in the composite laminates containing more layers. The scanning electron microscope was used to observe the dispersion and agglomeration of MWCNTs in the resin epoxy, and there was also an improvement in the fiber–resin bonding. [ABSTRACT FROM AUTHOR]

The presence of a secondary phase between the fibres and the matrix has proved to be a good approach for interphase tailoring for enhanced load transfer. In this regard, an optimization of the low-temperature hydrothermal growth process of ZnO-nanorods on different basalt substrates as a function of different growth times was performed. Scanning electron microscope and X-ray diffraction analysis revealed the best results in terms of homogeneity and uniformity of the ZnO nanostructures for the longest growth time, i.e., 5 h for basalt fabrics and 120 minutes for single basalt fibres. The presence of ZnO nanostructures induced a hydrophobic behaviour with contact angles up to 116° for 4- and 5-h growth processes. Fibre/matrix adhesion was characterized by single fibre pull-out tests, showing a 16% increase in interfacial strength. ZnOs added also photocatalytic properties to basalt fibres, enabling a selective removal of organic pollutant equal to 37%. [ABSTRACT FROM AUTHOR]

This research work is focused on development of epoxy based fiber metal laminate (FML) that comprised of multi‐walled carbon nano‐tube (MWCNT), glass fiber, and aluminum metal sheet. The hand layup technique was employed to fabricate the sandwich FML with different weight percentages (3, 4, and 5 wt%.) of MWCNT. The mechanical properties of the developed FMLs were determined through tensile, flexural, lap shear, and hardness tests following ASTM and IS standards. The scanning electron microscope (SEM) was used to characterize the failure mechanism of composites. The FML with MWCNT offered superior tensile and shear properties up to the addition of 4 wt%. The MWCNTs were found to be agglomerated in the epoxy when added more than 4 wt%. The FML's showed larger deformation before complete failure in shear mode with respect to the addition of MWCNTs. However, there was no considerable improvement recorded in the flexural and impact behavior of the FML composition. The addition of MWCNT fillers in the epoxy turned it more brittle and exhibited comparatively less deformation before failure in flexural mode. [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]

The present research venture focuses on utilization of food and agricultural waste Citrus limetta (musambi) peel by using it as a filler material to develop novel epoxy (EP) composites. Experimental investigation has been performed to analyse the influence of C limetta (musambi) peel particles (CLPP) on mechanical properties (tensile, flexural and impact strength) of the developed composites. Different loadings by weight percentages (0, 5, 10 and 15 wt%) of filler have been used to explain the variation in mechanical properties. Along with effect of different filler percentages, failure characteristics of the prepared samples have also been studied. The results indicate that higher CLPP content in EP matrix has a detrimental effect on mechanical properties of manufactured biocomposites. Thermal characterization was performed to analyse the degradation behaviour and the onset temperature. Morphological analysis of the fractured surfaces was also conducted with the help of a scanning electron microscope. The current experimental investigation has revealed that CLPP can be used as a potential filler for manufacturing biocomposites with applications in general purpose interior fitments in addition to various non-structural components. [ABSTRACT FROM AUTHOR]

In this study, the effect of particle size and particle content of silicon carbide fillers in epoxy matrix on the mechanical properties and microstructure of the developed composites was investigated. Silicon carbide fillers sized to < 45 μm and 90–45 μm were incorporated to epoxy composites to obtain volume fractions of 2, 4, 6 and 8 wt% of SiC. Mechanical properties including flexural strength, compressive strength and hardness tests of the composite samples were performed according to ASTM D790-03 (2003), ASTM D695-15 (2015) and EN 1534 standards. Surface morphology, crack propagation and particulate dispersion were observed using scanning electron microscopes (SEM). The results of the mechanical properties obtained were examined statistically and the results that a strong negative correlation between hardness and flexural strength but the individual correlation between hardness and flexural modulus, compressive stress and compressive modulus were positive. Results also showed that the inclusion of small particulate silicon carbide (< 45 μm) displayed superior mechanical properties in term of flexural, compressive and hardness characterizations at a given volume fraction. Flexural properties of the composite samples decrease with increase in filler concentrations while the compressive strength and hardness increase as particulate loading increase. In terms of microstructure, uniform dispersion of silicon carbide particulates was observed within epoxy matrix with linear crack propagation. [ABSTRACT FROM AUTHOR]

• Effect of voids and thermal aging on mechanical strength of epoxy resin is quantitatively evaluated. • Weibull statistics is applied with a defect density parameter and scattering index m. • Thermal aging and severe voids result in 15% increase in ρ , 53% drop in tensile strength and 74% decrease in m. • Under high reliability region (0.0005% failure), much lower tensile strength (1.18 MPa) is allowed based on the weibull analysis. • Thermal degradation of the epoxy material is found to be closely related to oxygen diffusion. Epoxy resin is widely used in electrical engineering, and its long-term mechanical performance is directly related to the durability of the equipment. The issue might be aggravated when voids are introduced during manufacturing process and when the material is used under high temperature environment. This study aims to precisely reveal the effects of voids and thermal aging on mechanical strength of epoxy resin. Specimens with low and high void content were prepared and thermally aged at 105 ℃ for various lengths of time. Tensile test, scanning electron microscope (SEM) and the finite element simulation were employed to investigate the failure mechanism. The chemical change due to thermal aging was studied by Fourier Transform Infrared Spectroscopy (FTIR). The results illustrate the crack is initiated at the edge of the void due to stress concentration. With the increased void content, there was a slight decrease in the mean tensile strength but a large (108%) increase in the standard deviation. During thermal aging, the chain scission and oxidation were observed via FTIR, along with the inhomogeneity of chemical compounds. A defect density parameter ρ was proposed and integrated into the Weibull distribution to study the synergistic effect of voids and thermal aging on the mechanical properties. This statistical analysis quantitatively describes the decrease in average tensile strength and the increase in data scattering with ascending defect density ρ , due to higher void content and thermal aging. When 0.0005% failure probability is required, the predicted failure stress is significantly reduced from 49.6 MPa to 1.18 MPa for the specimen with high level of void after the long-term aging. In this work, we demonstrate that Weibull statistical analysis can quantitatively evaluate the impact of void defects and thermal aging and provide strength design for the high-reliability epoxy material. [ABSTRACT FROM AUTHOR]

Natural fibres were extracted from plantain (Musa paradisiaca) pseudostem and modified using high-frequency microwave irradiation under different conditions in terms of power and time. First, the mechanical and morphology of treated and untreated fibre were investigated. Mechanical (tensile) properties test results reveal that microwave radiation at 550 W power was able to improve the tensile strength and modulus of the fibre. Scanning electron microscope (SEM) analysis shows surface roughness of the fibre has increased and uniform surface roughness was achieved. However, higher power and time of microwave irradiation causes a decrease in the mechanical properties the fibre as SEM image reveals the serious damaging effect on the surface of the fibre, due to degradation and rupturing of fibre cells by the exposure of inner central lumen of the fibre. In the second part, fibre-polymer biocomposite was fabricated using epoxy as the polymer matrix. Tensile and flexural test results reveal an increase in strength at optimised microwave power and time. A decrease in mechanical properties was observed at prolong and higher power radiation. Water absorption of fibre-polymer biocomposite was found to decrease after treatment at lower irradiation, interfacial adhesion of fibre-matrix was shown to increase with surface modification as reveals by SEM micrograph. [ABSTRACT FROM AUTHOR]

Theoretical and experimental studies on the compressive mechanical behavior of 4-harness satin weave carbon/epoxy composite laminates under in-plane loading are conducted over the temperature range of 298–473 K and the strain rate range of 0.001–1700/s in this article. The stress–strain curves of 4-harness satin weave composites are obtained at different strain rates and temperatures, and key mechanical properties of the material are determined. The deformation mechanism and failure morphology of the samples are observed and analyzed by scanning electron microscope (SEM) micrographs. The results show that the uniaxial compressive mechanical properties of 4-harness satin weave composites are strongly dependent on the temperature but are weakly sensitive to strain rate. The peak stress and elastic modulus of the material have the trend of decrease with the increasing of temperature, and the decreasing trend can be expressed as the functional relationship of temperature shift factor. In addition, SEM observations show that the quasi-static failure mode of 4-harness satin weave composites is shear failure along the diagonal lines of the specimens, while the dynamic failure modes of the material are multiple delaminations and longitudinal splitting, and with the increasing of temperature, its longitudinal splitting is more serious, but the delamination is relatively reduced. A constitutive model with thermomechanical coupling effects is proposed based on the experimental results and the increment theory of elastic–plastic mechanics. The experimental verification and numerical analysis show that the model is shown to be able to predict the finite deformation behavior of 4-harness satin weave composites over a wide range of temperatures. [ABSTRACT FROM AUTHOR]

The effects of perlite particulate-filler on the mode I and mode II interlaminar fracture and mechanical behavior of glass fabric/epoxy composites were studied. Composite specimens for double-cantilever beam (DCB), end-notched flexure (ENF) tensile and flexural tests were prepared and tested according to ASTM standards with perlite contents of 1, 3, 5 and 10 wt%. The optical and scanning electron microscopes images were described the mechanisms of mode I and II interlaminar fracture. The results indicated that the mode I and mode II interlaminar fracture toughness were optimum at perlite content of 3 wt% with increment of 39.9% and 72.3%, respectively. The tensile strength and flexural properties reached maximum values at perlite content of 1 and 5 wt%, respectively. [ABSTRACT FROM AUTHOR]

The objective of the present investigation is to study the alteration in flexural performance of glass/epoxy (GE) composite with and without multiwalled carbon nanotube (MWCNT) after liquid nitrogen conditioning. The epoxy resin was first modified by 0.1, 0.3, and 0.5 wt% MWCNT, which was then used along with E-glass fibers to fabricate laminates. Flexural strength and modulus were evaluated by 3-point bend test. Out of these four compositions, the maximum strength in the as-fabricated condition was obtained for GE composite with 0.1 wt% CNT, which is 32.74% higher as compared to GE composite. Decrease in strength and modulus was observed for short time span of liquid nitrogen conditioning i.e. 0.25 h. Long cryogenic conditioning resulted in increment in strength. To understand the failure mechanisms, post failure analysis was carried out using scanning electron microscope. The design parameters are calculated using Weibull distribution model. [ABSTRACT FROM AUTHOR]

A study was carried out involving the filling of epoxy resin (EP) with bentonites and silica modified with polyhedral oligomeric silsesquioxane (POSS). The method of homogenization and the type of filler affect the functional and canceling properties of the composites was determined. The filler content ranged from 1.5% to 4.5% by mass. The basic mechanical properties of the hybrid composites were found to improve, and, in particular, there was an increase in tensile strength by 44%, and in Charpy impact strength by 93%. The developed hybrid composites had characteristics typical of polymer nanocomposites modified by clays, with a fine plate morphology of brittle fractures observed by SEM, absence of a plate separation peak in Wide Angles X-ray Scattering (WAXS) curves, and an exfoliated structure observed by TEM. [ABSTRACT FROM AUTHOR]

This study focuses on the development of epoxy/luffa composites and the investigation of their mechanical and acoustical properties. The fibers underwent an alkalization treatment, and its effects on the mechanical and sound absorption properties of the composites were measured utilizing a universal testing machine and two-microphone transfer function impedance tube methods. The effects of chemical modifications on the fibers were studied using a scanning electron microscope (SEM). The thermal analyses of composites were conducted using thermo-gravimetric analysis (TGA). The composite's functional group was identified and evaluated using Fourier transform infrared spectroscopy (FTIR). The sound absorption coefficient of untreated and treated composites across a range of frequencies was very similar. Untreated composites appeared to perform better than those that were treated. Compared with untreated fiber composites, there was an improvement in the tensile strength of the treated fiber composites. The SEM characterization showed that the alkaline treatment changed the morphology of the fibers, resulting in a decrease in the sound absorption coefficients of the composites. The thermal characterization of composites showed that dehydration and degradation of lignin occurred in a temperature range of 40 to 260 °C, and the maximum percentage of cellulose was found to decompose at 380 °C. [ABSTRACT FROM AUTHOR]

A novel thermoplastic epoxy (TPE) was constructed through the solution polymerization process between diglycidyl ether of bisphenol A (DGEBA) and aniline to improve the performance of epoxy thermosets. Its cure kinetics, molecular structure, thermal and mechanical properties were investigated. Due to the similar chemical structure, the TPE exhibits excellent compatibility with DGEBA and DGEBA-based thermosets. The results of the mechanical properties of cured TPE/DGEBA composites demonstrate that the appropriate content of TPE (15 phr) can significantly improve the mechanical properties including the tensile strength, tensile fracture strain, flexural strength, flexural fracture detection and fracture toughness, which is associated with the formation of semi-IPN structure of TPE and DGEBA-based thermosets. The corresponding mechanism for enhanced properties of TPE/epoxy composites was investigated deeply by scanning electron microscope. And, the tensile and flexure modulus, glass transition temperature and thermal stability of TPE modified DGEBA based thermosets demonstrates a slightly decrease tendency with the addition of TPE, which can be attribute to the coupling effect between the uncrosslinked chain structure of TPE and the strong interaction of hydroxyl between TPE and DGEBA thermosets. [Display omitted] • Thermoplastic epoxy (TPE) was synthesized from bisphenol A epoxy and aniline. • The TPE exhibited excellent compatibility with epoxy and epoxy thermosets. • Introduction of TPE could significantly improve the toughness of epoxy thermosets. [ABSTRACT FROM AUTHOR]

Effect of silicon carbide and aluminium oxide fillers on tension, flexural, compression, and impact properties of woven jute fabric reinforced epoxy composite has been investigated experimentally. Several laminates were prepared by hand lay-up technique by varying the percentage of filler addition. Tests (except impact) were conducted on computer interfaced universal testing machine as per ASTM standards. Impact tests were conducted on pendulum impact testing machine. The results of the tests indicated that addition of filler has significant effect on these properties. Laminate with 10 wt% of filler (based on resin) exhibited the highest properties. The properties were found to decrease beyond 10 wt% of filler loading. The mode of failure was also studied for selected samples using scanning electron microscope. [ABSTRACT FROM AUTHOR]

This study is concerned with the preparation and mechanical characterization of bio-based polymers from renewable resources. Epoxidized soybean oil at various concentrations is cured with an amine curing agent. The prepared matrices have been chemically modified with three types of bismaleimides, namely N, N'-bismaleimido-4, 4'-diphenyl methane (BMI-1), 1,3-bis(maleimido)benzene(BMI-2) and 3,3'-bis(maleimido phenyl)phenyl phosphineoxide (BMI-3). The crosslinked matrices thus developed were characterized for their mechanical properties such as tensile strength, tensile modulus, flexural strength, flexural modulus, and impact strength. The incorporation of bismaleimides in the soy-based matrices significantly enhances the mechanical properties. The morphological behavior of matrices is also studied using a scanning electron microscope. The results indicate that the bismaleimide-modified soy-based epoxy resin at appropriate concentration holds great potential as a replacement for petroleum-based materials in engineering applications. [ABSTRACT FROM AUTHOR]

• Epoxy resins were affected mechanically and chemically from corrosive environment significantly. • While the acidic environment aging adversely effects the properties of epoxy resin, it is determined that salty water environment aging increase the strength of epoxy resin. • The MWCNT nano particles reinforcement diminish the endurance of epoxy resin against the aging environment. In this study, the effects of different harsh aging environments on the chemical and mechanical properties of neat and multiwall carbon nanotubes (MWCNT) reinforced epoxy resins were investigated. The neat and 1 wt% MWCNT reinforced epoxy resins were exposed to four different corrosive environments, namely deionized water, NaCl solution (10 wt% NaCl), H 2 SO 4 solution (10 wt% H 2 SO 4), and HCl solution (10 wt% HCl. The mass variation results revealed that the highest absorption rates were found in specimens aged in both acidic environments. The highest amount of absorption was observed in the H 2 SO 4 environment, measured approximately 3% for neat epoxy , and 6.5% for MWCNT reinforced epoxy resin. FT-IR spectrums showed that the most affected peaks belong to specimens aged in both acidic environments. Tensile test results revealed that the aging process in H 2 SO 4 solution and deionized water deteriorated the strength of specimens. According to the literature, it was reported that the strength of specimens aged in NaCl solution environment is decreased. However, the same trend has not been in this study. In our study, the strength of specimens aged in NaCl solution environment increased impressively by 29%, which makes this study more striking. Another important point analyzed from the tensile test results was that the MWCNT nanoparticle reinforcement adversely affects the strength of the epoxy resin. So, it can be clearly stated that the use of expensive MWCNTs as filler of epoxy resin is not useful to improve its aging resistance. The scanning electron microscope (SEM) and optical microscope images showed that acidic environments result in different fracture mechanisms from typical polymer damaged surfaces reported in available researches. [ABSTRACT FROM AUTHOR]

• The mechanical properties of EP/PU were optimized by RSM with CCD method. • Influence of MWCNT on mechanical and chemical properties of EP/PU was investigated. • TGA curves of EP/PU/MWCNT nanocomposite showed higher thermal stability compared to the EP and EP/PU composite. • Molecular dynamic simulation was used to calculated the surface interaction energy. In this research, the effect of three factors amounts of polyurethane, post-curing temperature and time on the mechanical properties of epoxy/polyurethane (EP/PU) composite have been studied. Response surface methodology (RSM) coupled with central composite design was used to optimize the mechanical properties of these composites. The optimization results also show that yield strength and Young's modulus at optimum value improved up to 23.3% and 10% compared to neat epoxy matrix. The chemical structure of the EP/PU composites were characterized by FT-Infrared (FT-IR), X-ray diffraction (XRD), scanning electron microscope (SEM), UV–vis diffuse reflection (DRS) and Thermogravimetric analysis (TGA), also the mechanical properties were obtained by Dynamic Mechanical Thermal Analysis (DMTA) and tensile test measurements. The FT-IR spectra indicate a very weak interaction between EP and PU. Also, the influence of multi-wall carbon nanotube (MWCNT) with different concentrations (0–0.25 wt.%) on mechanical and physical properties of EP/PU matrix was investigated. The interaction behavior of the MWCNT with EP/PU as a matrix was investigated using XRD, FT-IR and molecular dynamic (MD) simulations. Dispersion of MWCNT in the EP/PU composite was also observed using SEM. The yield strength of EP/PU/MWCNT nanocomposites increased about 59.7% with the addition of 0.15 wt.% MWCNT nanofiller. Image, graphical abstract [ABSTRACT FROM AUTHOR]

A comprehensive and comparative experimental study has been conducted to investigate the effect of thermal-oil ageing on mechanical, thermal and internal structural properties of E-glass fibre/epoxy composite materials. E-glass fibre/epoxy composite specimens were divided into 8 groups according to the certain experimental ageing temperatures. The temperature values were selected as −10, 25, 50, 80, 100, 120 and 140 °C, while the values of the ageing duration were selected as 24, 168, 360, 720 and 1080 h. Thermogravimetric Analysis (TGA) and Differential Thermal Analysis (DTA) tests were performed to determine the thermal properties, tensile tests were used to detect the mechanical properties and a Scanning Electron Microscope (SEM) was used to illustrate the changes in the internal structure of the composites. As a result of this work, unexpectedly no alteration was observed in the mechanical properties of the specimens aged at −10 °C; however, ageing at 120 and 140 °C reduced the maximum load carrying capacities (LCCs) of the specimens especially for further ageing exposure times. Furthermore, the thermal stability of the specimens aged at −10 °C increased with the increasing thermal ageing duration while, for the other thermal ageing temperatures, the thermal stability showed a decreasing trend as the thermal ageing exposure time increased. [ABSTRACT FROM AUTHOR]