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The organic composite materials are very competitive due to their low density and good flexibility by design, suitable for certain working conditions such as installations where high mechanical strength at a low weight is required. Additionally, they contribute to the environment by taking advantage of organic components that are currently waste. The composite proposed in this work consists of an epoxy matrix reinforced with African palm rachis fibers. The specimens were manufactured under the manual rolling process due to the nature of the reinforcement. Moreover, the variation of the interlaminar tensile strength was investigated, using a four-point flexion testing and varying the thickness of the specimen in order to evaluate the feasibility of the organic reinforcement. The experimental analysis was performed with a curved beam geometry and low flexion.

Cellulose nanowhiskers were prepared by acid hydrolysis of drumstick fruit fibers from Moringa oleifera. It was incorporated into thermosetting epoxy matrix at various weight fractions (0.06, 0.12 or 0.18 wt%) to investigate their effect on the mechanical and thermal properties of resulting epoxy resin composite. Drumstick fruit nanofibers slightly increased the thermal stability of the prepared composites. The tensile modulus (31.4%) and bending modulus (38.2%) of the epoxy composites filled with 0.18 wt% cellulose nanowhiskers significantly increased in comparison with that of the neat cured epoxy resin. However, the tensile strength (48.7%) and bending strength (41.6%) of the composites significantly decreased as the 0.18 wt% nanowhiskers were added into the epoxy matrix. The nanowhiskers (0.18 wt%) can be efficiently used in the epoxy matrix to improve considerably the tensile and bending modulus of the composites as well as a slight increase in the thermal stability.

Banana short fiber/Al(OH)3/epoxy composite laminates were prepared by dispersing short banana fiber and Al(OH)3 particulates in an epoxy matrix and investigated for their specific wear rate...

The compressive response of 3D woven textile composites (3DWTC), that consist of glass fiber tows and an epoxy matrix material, is studied using a finite element (FE)-based mechanics model. A param...

To improve the interfacial adhesion between carbon fibers and an epoxy matrix, carbon fibers were modified by oxyfluorination at different temperature conditions. Surface analyses of the oxyfluorinated carbon fibers were performed using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and dynamic contact angle measurements. The interfacial shear strength (IFSS) of a single carbon fiber/epoxy matrix was studied by employing single-fiber pull-out tests to confirm the interfacial adhesion. The pull-out behavior of the fiber from the matrix was discussed based on the Greszczuk’s geometrical model. Functional groups such as C-F, C-O, and COOH were present on the carbon fiber surfaces after oxyfluorination. Moreover, the presence of functional groups increased the surface polarity of the fibers, resulting in an increase in the IFSS owing to the improvement of the interfacial adhesive strength between the carbon fibers and the epoxy matrix.

The effects of nano-particles on the electrical properties of the epoxy/ZnO nano-composites are studied and the nonlinear conduction characteristics of the nano-composites are discussed. The morphology structure, relative permittivity, DC breakdown strength and DC conductivity of the nano-composites are measured. Micro-structure analysis shows that the ZnO nano-particles were well dispersed in the epoxy matrix. Experimental results show that the relative permittivity and DC conductivity of epoxy nano-composite with the filler loading of 0.5 wt% are lower than those of pure epoxy and the other nano-composites, but the 0.5 wt% has the highest breakdown strength among the epoxy/ZnO nano-composites. In addition, when the filler loading is larger than 0.5 wt%, the epoxy/ZnO nano-composite exhibits a distinct nonlinear conduction character, namely, that the DC conductivity is greatly dependent on the applied electric field. The variation of the electrical properties and the nonlinear conduction character against the filler loading may be attributed to the interaction zone around the nano-particles.

WOS: 000433239500015, The influence of alumina (Al2O3) nanoparticles addition upon low-velocity impact behaviors of carbon fiber (CF) reinforced laminated epoxy nanocomposites have been investigated. For this purpose, different amounts of Al2O3 nanoparticles ranging from 1 to 5 wt% were added to the epoxy resin in order to observe the effect of nanoparticle loadings. CF reinforced epoxy based laminated nanocomposites were produced using Vacuum Assisted Resin Infusion Method (VARIM). The low velocity impact (LVI) tests performed according to the ASTM-D-7136 standard under 2, 2.5 and 3 m/s impact velocities. After LVI testing, the damage formations within composites were examined by using scanning electron microscopy (SEM). The results of this study showed that addition of Al2O3 nanoparticles provided a significant improvement in impact damage resistance. The highest damage resistance and minimum energy absorption were observed for 2 wt% Al2O3 nanoparticles loadings. As a result, we can confidently claim that the addition of the Al2O3 nanoparticles in CF/epoxy composites has considerably affected the dynamic response of the nanocomposites. (C) 2018 Karabuk University. Publishing services by Elsevier B.V.

In the present study, moisture uptake behavior and their effect on mechanical properties of plant fibers were investigated while these fibers were reinforced with epoxy matrix. The develope...

A comprehensive understanding of strain history in resin matrix composite, which is caused by variability of thermo-mechanical properties of the resin during composite processing, is essential to allow better design and control of properties of the resin matrix composite. In this paper, to know strain history of fast curing epoxy matrix composite and differences of strain history between fast and conventional curing epoxy matrix composites well, temperature and strain history at different locations in ten-ply unidirectional carbon-fiber fabrics reinforced the fast and conventional curing epoxy matrix composite laminates manufactured by wet lay-up method were measured by fiber Bragg grating (FBG) sensors. Results shown that the peak temperature due to curing exothermal reaction was 133.7 °C in both the 1st ply and the 5th ply in the fast curing composite when cure temperature profile settled at 80 °C, which was 27.4 °C higher than that in the conventional curing composite. Cure residual strain in the 1st ply and the 5th ply in the fast curing composite were −5183.3 μe and −4074.7 μe, respectively; while they were −2975.9 μe and −2660.8 μe in the conventional curing composite. The related properties of rheology and cure kinetics of the epoxy resin were thus given in advance.

In this study, a linseed oil encapsulated self-healing coating was developed by incorporating 10 wt% synthesized microcapsules into an epoxy-polyamine coating matrix. The linseed oil encapsulated polyurea-formaldehyde (PUF) microcapsules had ∼80 wt% core content with ∼80 um diameter. The influence of embedded microcapsules on the anticorrosive property of the self-healing coating had been studied by electrochemical impedance spectroscopy. The intact self-healing coating exhibited excellent anticorrosive property as the intact pure epoxy coating, although the addition of microcapsules into the epoxy matrix resulted in a higher water-uptake. The scratched self-healing coating showed excellent healing ability and corrosion inhibition function for microcracks, but it still cannot recover the barrier property as good as the intact coating. The failure of the scratched self-healing coating had been analyzed and the possible reason may be the formation of conductive pathways at the interface between the linseed oil film and the epoxy matrix and/or PUF microcapsule shell.

Multiscale glass fiber epoxy matrix composites containing nanodiamonds were fabricated using vacuum bagging technique. Three different loadings of nanodiamonds were incorporated in epoxy resin afte...

We developed a system involving an extrinsic self-healing coating to identify cracked and healed regions by their yellow fluorescence and blue fluorescence, respectively. This system consisted of a top coating, an epoxy matrix resin containing a yellow fluorescent dye, and a microcapsule. This microcapsule in turn consisted of a healing agent, a blue aggregated-induced emitting luminogen, and a photo-initiator, as well as poly(urea-formaldehyde) as a shell material. Embedding the self-healing coating with a 25 mass% of microcapsules yielded the most efficient fluorescence detection and healing of the damaged region. Scratched and healed regions were successfully detected using our system under UV irradiation as well as under a one sun condition similar to sunlight. The blue fluorescence of the healed region was easily seen from 2 m away.

Functionalized multiwalled carbon nanotubes were successfully deposited on carbon fibers using four different techniques including dip coating, hand layup, spray up and electrophoretic deposition (...

This study was conducted to evaluate the development and characterization of granite powder reinforced epoxy composites. Granite powder in powder form acts as reinforcement in Epoxy matrix. The primary aim of this study was to investigate the effectiveness of these composite materials in the strength, weight and surface finish. It has the capability of replacing the present materials due to its eco-friendly nature. The compositions with poor properties are considered noncompliant and can be rejected. In this study, the samples are subjected to various Physical and Mechanical tests like Izod impact test, Vickers hardness test and Moisture absorption. This work aims to account these results in order to obtain enhanced properties. It is found that resin ratio between 60% to 70% are the best suitable for the engineering and structural applications as well.

Alumina epoxy nanocomposite (AENC) is an emerging class of composites with a wide range of functionality and applicability; however, managing AENC using a machine is difficult because of its special mixed characteristics. The presence of extremely hard alumina particles in soft epoxy matrix enhances material properties. The present work investigates the kerf characteristics of a straight cut made in AENC through Wire electrochemical spark cutting (WECSC) process. The kerf characteristics, such as kerf deviation and taper, are used to measure the cut quality. The applied voltage, electrolyte concentration, wire velocity, pulse on-time and pulse off-time are varied, and their effects on the kerf characteristics are experimentally investigated in a developed setup. Influencing parameters for straight cutting of AENC are applied voltage, concentration of electrolyte and wire velocity.

This work presents the results of research on mechanical properties of hybrid polymeric composite materials (PCM) with different percentage of carbon filler FormosaTC-35 (12K) and glass filler T-10-14 in epoxy matrix Т-107. It was established that carbon-glass plastics are more preferable with respect to mechanical properties for application in constructions which work in bending.

This work was focused on studying the properties of epoxy (EP) composite materials reinforced with glass, (GF) carbon (CF) and aramid (AF) fibres. The composites were made by hand lay-up (HL) and vacuum infusion process (VIP) with 8, 10, 12 number of fabric layers. Studied were tensile strength, elongation, flexural stress, flexural strain, thermal stability, texture of surfaces, cuts, fractures of laminates and the thickness of the laminate according to the type and number of layers of fabric and the method of manufacture. Composites made by VIP achieve better mechanical properties than composites made by HL. Tensile strength was highest in composites reinforced with AF. Composite materials reinforced with GF exhibit the lowest values of tensile strength. Flexural strength was significantly the highest in CF reinforced composites followed by the laminates reinforced with GF and AF. The highest values of flexural deformation were measured in composites reinforced with AF and the lowest values of flexural deformation were measured in composites reinforced with CF. By thermogravimetric analysis (TG) was recorded weight loss of the EP matrix in the range from 290 to 480 °C and AF in range from 530 to 605 °C. By TG was demonstrated lower content of EP matrix in the composites made by VIP, which was confirmed by comparison of thickness of the studied laminates.

Improvement of existing composite material to obtain new composite materials is the real challenge for most of the materials engineers. So, there are huge research endeavors emerging in the field of composites to grow new materials with upgraded mechanical, electrical and thermal properties. Among these, fiber reinforced polymer composites are the most charming as a result of their sufficient utilization in different applications which incorporates numerous mechanical, automotive and structural components. The present study investigates the mechanical characteristics of a Kevlar/glass fiber reinforced with Cloisite 30B nanoclay. Kevlar fibers have been widely used as impact-resistant reinforcement in composite materials. However, there are very few works about the effects of nanoclays on the impact strength of Kevlar/glass laminates. Nanoclay Cloisite 30B (2 wt.-%) was dispersed in the epoxy system. Such laminates manufactured with epoxy resin filled by 2 wt.-% of nanoclay showed the best performance in terms of elastic recuperation and penetration threshold. The opposite tendency was observed for the displacement at peak load. However, marginal benefits can be found when compared with the results obtained for laminates filled by 2 wt.% nanoclay. Kevlar/glass fibers were reinforced with different particulate fractions of chosen nanoclay and the specimens were investigated regarding mechanical properties such as tensile, impact and flexural strength.

In this study, a multiscale cellulose fiber interlayer consisting of chopped flax fibers (FFs) and cellulose nanofiber (CNFs) was proposed for enhancing the interlaminar fracture toughness of carbon fiber/epoxy composites. The cellulose fiber interlayer was treated by waterborne epoxy to improve the interfacial compatibility with the epoxy matrix. The end-notched flexure results showed that the addition of the cellulose fiber interlayer in the carbon fiber/epoxy composites resulted in a remarkable increase in Mode II interlaminar fracture toughness, which was attributed to a synergistic effect of the FFs and the CNFs. The 3D network of the chopped FFs alleviated the agglomeration of the CNFs due to their good compatibility, leading to more fiber bridging and fiber pull-out during delamination . The presence of CNF further improved the interfacial properties of the FFs and epoxy matrix, which are beneficial for the fibrillation of flax fiber to hinder interlaminar crack growth.

In the first part of this two-part paper (Part 1), the low-velocity impact (LVI) response of bolted fiber-reinforced polymer joints was investigated considering with two scenarios based on the localized impact damage as the impactor hit on the top of the bolt (ToB) and the side of the washer (SoW). Moreover, the influence of halloysite nanotubes (HNTs) reinforcement of the epoxy matrix on the impact performance was also evaluated. As the second part of the research, this paper represents the effects of seawater aging on the LVI response of FRPs. For this, the composite joints were submerged in an artificial seawater environment for six months to accelerate aging. Afterward, as following the systematic experimental path exhibited in Part 1, LVI tests were conducted by dropping the impactor on ToB and SoW regions. The test results showed that the seawater aging impaired almost 30% of the composite joints' impact resistance, where HNTs reinforced multi-scale composite joints exhibited a 13% higher impact loading performance. The ToB impact scenario was considered as visually and quantitatively more detrimental than the SoW tests. The detrimental impact of seawater aging was validated by tracking the elemental evolution in the seawater environment. Based on the mechanical, morphological, and structural analyses, a novel damage mechanism was introduced to address seawater aging's progress, including the role of nanoreinforcements.

Today, there are many more applications for fibre reinforced polymer composites than there were for metals and alloys a few decades ago. Numerous research projects have focused on improving the mechanical and thermal properties of composite materials, especially when reinforced with environmentally friendly, recyclable, and biodegradable materials. This study combined alpaca fibre (AF), palm seed filler (PSF), and polypropylene (PP) to create composites that have improved properties over traditional polymer composites. Fiber loadings of 35, 30, 25, 20, 15, and 10 percent and filler loadings of 15, 10, and 5 percent were used to prepare the alpaca fiber/palm seed filler polypropylene (PP) composites using a conventional injection moulding technique (0, 5, 10, 15, 20 and 25 wt. percent ). Hydrophilicity and mechanical properties of the hybrid bio-composites were evaluated experimentally. The results showed that 15 lbs. For example, epoxy matrix composites have tensile and flexural strengths of 62 MPa, as well as hardness and impact strengths of 54 and 17.9 kJ/m2, respectively.

The purpose of this study is to further the search for the optimal conditions for the recovery of recycled carbon fiber (rCF) from epoxy matrix CFRP by thermal decomposition. We revealed that an oxidizing atmosphere was required to recover rCF. By investigating the strength reduction of CF after the heat treatment (hCF), it was demonstrated that significant strength reduction occurred at 600 °C. The damage also depended on the treatment temperature and time because of the oxidative decomposition of the fiber surface. By comparing the virgin CF, hCF and rCF, it was demonstrated that the strength reduction of the rCF was caused not only by the thermal oxidative decomposition but also by its interaction with the resin. Additionally, the time required to recover rCF differs depending on the treatment temperature and the degree to which each effect on the CF in CFRP depended on the location of the CF. At low temperatures, recovery time was longer, and the differences in strength between rCF recovered from the inner and outer layers were large. although CF recovery was quick at high temperatures, but the strength was significantly lower because of the effect of the interaction with the resin.

In this research, the effects of hybrid nanoparticles Fe3O4+Ni on the magnetic and dielectric properties of epoxy resin are investigated. Microstructural characterization was performed by Field Emission scanning electron microscopy FESEM, X-ray diffraction spectra XRD, and Fourier-transform infrared spectroscopy (FTIR). The magnetic properties were investigated by vibrating sample magnetometer (VSM) and the dielectric response was investigated by a precision impedance analyzer (Agilent 4294A) LCR meter at room temperature with different frequencies. The study dealing with hybrid nanocomposite (epoxy/Fe3O4+Ni) consisting of epoxy resin as the matrix material reinforcing by magnetite nanoparticles (Fe3O4) with different weight percentages (3wt.%, 6wt.%, 9wt.%, 12wt.%, 15wt. %) and constant weight percentage 2wt% of nickel (Ni) nanoparticles. The samples were prepared using the casting method. The epoxy with the hardener is weighted and mixing in a 2:1 ratio and then add reinforcement materials Fe3O4+Ni into the epoxy. Microstructural analysis showed that a uniform distribution and homogeneously dispersed in the epoxy matrix. The results of this work exhibit that the Increasing additive weight percentages of Fe3O4 nanoparticles with a constant weight of Ni nanoparticles into epoxy resin led to improvement in the magnetic and electric properties of hybrid nanocomposites compared with pure epoxy.

This article describes new control criteria and robust optimization methodology to balance drilling parameters and machining characteristics. Experimentation was performed according to response surface methodology (RSM) using a TiAlN coated SiC tool. The full drilling force signal and cutting parameters tested are categorized into five stages, indicating the drilling tool-workpiece interactions’ different statuses. Principal component analysis (PCA) assigns real response priority weight during the aggregation of conflicting characteristics. The hybrid module of combined compromise solution and PCA (CoCoSo–PCA) is used to decide the optimal parametric setting. It efficiently undertakes a trade-off between minimal thrust ([Formula: see text][Formula: see text]N), torque ([Formula: see text][Formula: see text]Nm) surface roughness ([Formula: see text]m). A regression model between input parameters and output function was established using RSM quadratic model. The validation experiment shows significant improvement, and the proposed module can be recommended for quality-productivity characteristics control.

In this study, graphene oxide (GO) with long flexible amino-rich structure, i.e., GO-COOH-T403, was prepared by grafting trifunctional polyether amine (T403) to the surface of in-situ carbonylated GO. The amino-rich GO nanosheets were employed to modify epoxy resin and fabricate multiscale carbon fiber (CF), respectively. Basing on that, carbon fiber reinforced polymer (CFRP) composites with superior interlaminar behavior were obtained via impregnating multiscale CF with the amino-rich GO modified epoxy. The interlaminar analysis indicated that simultaneously applying amino-rich graphene oxide to CF and epoxy matrix could effectively optimize the interlaminar properties of the resulting composites. Notably, the value of ILSS for multiscale CF reinforced amino-rich GO modified epoxy composites was 82.2 MPa and 32.6% higher than that single employed amino-rich GO into epoxy matrix or onto CF exhibiting a synergistic behavior. Therefore, this work was expected to provide new inspiration for developing high-performance CFRPs with excellent interlaminar properties.

International audience; We describe a new method to quantify the anisotropy ratio of hydric strains acquired at the gallery scale and over a period of at least one year. This method was applied in the context of an investigation conducted on a gallery front of the Experimental Station of Tournemire (France), which was subjected to a natural seasonal cycle. Our approach was based primarily on a new algorithm for Digital Image Correlation, known as H-DIC, which can accurately locate desiccation cracks and extract fifteen uncracked blocks with quantified sub-vertical and sub-horizontal strains.The values of the anisotropy ratio of hydric strains (i.e., the ratio of the sub-vertical strains to the sub-horizontal strains, or the ratio of the strains perpendicular to the bedding to those parallel to the bedding) are in the range of [2.84–5.35], with a mean value close to 4.2.The anisotropy ratio for the hydric strains appears to be independent of the natural cycle (i.e., hygrometry) present in the gallery. This observation is supported by a theoretical estimation of this anisotropy ratio, which suggests that the poroelastic parameters of clay rock are insensitive to climatic changes or that theirs evolutions roughly cancel each other out. With regard to geometrical patterns (area, width, height, aspect ratio and orientation) calculated for the uncracked blocks, the anisotropy ratio of the hydric strains does not depend on the area of these uncracked blocks.Moreover, a literature review shows that the values of the anisotropy ratio for the hydric strains determined in this study are significantly larger than those obtained at the laboratory scale on undamaged samples or estimated from a theoretical relationship established in a poroelastic framework. These comparisons strongly suggest that damage to clay rock existing on the gallery front contributes to a significant increase in the anisotropy ratio of the hydric strains.

The object of this work is to study and predict the tensile properties (tensile strength, elastic modulus, and elongation at break) of ternary nanocomposites based on epoxy/glass fiber/nanosilica using the fuzzy logic (FL). Two factors in three levels including glass fiber at 0, 5, and 10 wt% and nanosilica at 0, 0.5, and 1 wt% were chosen for adding to an epoxy matrix. From FL surfaces, it was found that the glass fiber content had a main role in the tensile properties of nanocomposites. The high levels of glass fiber content led to a significant increase in the elastic modulus and generally, the presence of glass fiber decreased the tensile strength and elongation at break. Also, addition of the nanosilica content resulted in an increased elastic modulus but decreased the elongation at break of nanocomposites. Finally, an FL model was obtained for each tensile property.

In recent years, natural fibers have received much attention from various industrial applications. As these fibers are lightweight, nonabrasive, low cost, ecofriendly and biodegradable, they can be sometimes considered as alternatives to synthetic fibers in lightweight composite structures. In this work, date palm fibers (DPFs) were treated by oxygen plasma at various plasma discharge power and exposure time. The effects of plasma treatment on tensile strength of DPF and interfacial adhesion between DPF and epoxy were determined by single fiber tensile test and microbond test, respectively. Scanning electron microscopy was used to investigate the surface morphologies of DPFs before and after the plasma treatment. The functional groups on the surface were studied by attenuated total reflectance-Fourier transform infrared spectroscope (ATR-FTIR). Decrease in hemicellulose and lignin content of DPF was indicated in ATR-FTIR spectra of the treated sample with plasma treatment. The results show that plasma treatment cleans the fiber surface and increases the surface roughness by etching effect. Moreover, fiber surface modification significantly improves tensile properties of DPFs and interfacial shear stress (IFSS) of fiber/matrix. However, the effects of plasma power and exposure time on tensile properties and IFSS values of DPFs are not found significant. Moreover, Weibull statistics show that plasma treatment could not decrease the variability in fiber strength due to the nature of fibers.

Epoxy resins possess a variety of excellent properties including adhesion, mechanical performance, electrical insulation and chemical resistance; however cured epoxy resin is brittle and typically petroleum based. Rising concerns about depletion of nonrenewable resources and climate change have resulted in attempts to find green alternatives for petroleum based materials and mitigate greenhouse gas emissions. The present review is aimed to discuss green approaches to overcome epoxy resins brittleness and deal with ongoing research strategies to make tough biobased epoxies. First, the key toughening modifiers such as rubbers, thermoplastics, nanofillers, dendritic and block copolymers are briefly discussed and pros and cons of each method are presented. Then, the studies that followed green approaches are thoroughly reviewed. The utilization of epoxidized vegetable oils, biobased hyperbranched polymers and biobased copolymers in epoxy matrix are discussed. The challenges for commercialization of biobased m...

Studies show the possibility to directionally control the performance properties of epoxy composites by the use of small additions of whiskers of potassium polytitanate, the introduction of plasticizers of multifunctional action, and the methods of chemical and mechanical activation of composition components and the composition as a whole. This provides the creation of the next-generation epoxy composites with high performance (the breaking stress and the flexural modulus of 96 and 3150 MPa, the compressive breaking stress of 95 MPa, and the toughness of 18 kJ/m2), which meets the usual industrial requirements. In addition, the influence of potassium polytitanate whiskers on the structure formation processes of epoxy resin is established, which is shown by the increase in the gel time from 45 to 64 min and the curing time from 53 to 104 min.

The aim of this research is to measure the absorption coefficient of composite material synthesized from coconut fiber as filler and epoxy matrix and to discover the alternative interval of sound reducer material from natural resources, i.e (coconut fiber : fine fiber, rough fiber and crude fiber). After pressing, the sample was then cutted and examined using Bruel and Kjaer characterization. From the characterization process, the absorption coefficient of composite with filler of fine, rough and crude coconut fiber is calculated and found to be 0.997, 0.97 and 0.96, respectively. © 2015 JNSMR UIN Walisongo. All rights reserved.