Mechanical Properties Of Epoxy Nanocomposites Research Articles

Investigating of epoxy nanocomposites structure and properties that contain both pristine and aminosilane-treated silicon carbide (SiC) particles

This article presents a methodology for functionalization of silicon carbide (SiC) through chemical modification using γ-aminopropyltriethoxysilane (APTES) and its subsequent dispersion in an epoxy composition. The research revealed that functionalizing SiC particles with γ-aminopropyltriethoxysilane (SiC(APTES)) enhanced their chemical compatibility with the epoxy composition, facilitating the dispersion of SiC particles. Furthermore, it was observed that the functionalization of the filler had a profound impact on the structure, curing kinetics, and physical and mechanical properties of epoxy nanocomposites. The addition of SiC(APTES) into the epoxy composition resulted in a significant reinforcement of the material. Specifically, the flexural stress and flexural modulus of elasticity increased by 179% and 74%, respectively, while the impact strength experienced a remarkable improvement of 462%. Additionally, the tensile strength and tensile modulus of elasticity increased by 83% and 70%, respectively, compared to the epoxy composite without SiC. The application of SiC(APTES) also played a crucial role in initiating the polymerization process through the involvement of reactive amino groups, leading to a reduction in the initial curing temperature and an amplification of the thermal effects of the polymerization reaction. Moreover, the presence of functionalized SiC significantly influenced the structure of the epoxy composite, thereby contributing to its enhanced strength. In summary, the inclusion of SiC in the epoxy composition not only bolstered the material but also improved its thermal stability.

The Influence of Pristine and Aminoacetic Acid-Treated Aluminum Nitride on the Structure, Curing Processes, and Properties of Epoxy Nanocomposites

This article describes the preparation of aluminum nitride (AlN) functionalized with amino groups by chemically modifying the surface of AlN with aminoacetic acid and their dispersion in the epoxy composition. As a result of the studies, it was found that the functionalization of AlN particles with aminoacetic acid ensured their better chemical compatibility with the epoxy composition, which facilitated the dispersibility of AlN particles; it was also found that the functionalization of the nanofiller has a significant effect on the structure, curing kinetics, physicochemical and mechanical properties of epoxy nanocomposites. The optimal concentration of the functionalizing agent (aminoacetic acid) has been determined, which is necessary for the chemical binding of the functional groups of aminoacetic acid, the epoxy oligomer and AlN, which best affects the dispersion and the size distribution of AlN particles, and also ensures maximum strength characteristics of epoxy composites containing AlN treated with aminoacetic acid: bending stress and bending modulus increase by 35% and 80%, respectively, while tensile strength and tensile elastic modulus increase by 74% and 36%, respectively. Furthermore, the impact strength shows a remarkable boost of 133% compared to plasticized epoxy composite without AlN.

Dispersion characteristics and mechanical properties of epoxy nanocomposites reinforced with carboxymethyl cellulose functionalized nanodiamond, carbon nanotube, and graphene

AbstractCarbon‐based nanoparticles are widely regarded as promising nanofillers in nanocomposites to pursue advanced properties. To date, there has been a lack of systematic investigation into the structural variations of nanofillers and their influences on dispersion characteristics, as well as the resulting mechanical properties of nanocomposites. In this study, nanodiamond (ND), carbon nanotube (CNT), and graphene (GNP) were selected as the representative zero‐, one‐, and two‐dimensional nanofillers, respectively. A novel functionalization technique utilizing carboxymethyl cellulose (CMC) was employed to disperse nanofillers. The various characterization techniques and experimental results revealed that CMC functionalization was effective in reducing the agglomeration and improving the distribution uniformity of all three nanofillers. Among the three nanofillers, zero‐dimensional ND exhibited the most homogeneous dispersion quality in epoxy nanocomposites. The strongest abrasion resistance was found in ND‐reinforced epoxy nanocomposites, while CNT‐reinforced epoxy nanocomposites exhibited the best tensile properties.Highlights Nanodiamond with a spherical structure had better dispersion characteristics. Cylindrical carbon nanotube and planar graphene tended to agglomerate. Nanodiamond reinforced nanocomposites had better abrasion resistance. Carbon nanotube reinforced nanocomposites had better tensile properties. Carboxymethyl cellulose functionalization was valid for all three nanofillers.

Effects of functionalized CNTs in improving the dielectric, corrosion protection, and mechanical properties of epoxy nanocomposites for automotive/aircraft components

ABSTRACT Excellent mechanical, thermal, electrical, electrochemical, and optical properties can be found in carbon nanotubes (CNTs). The anticorrosive and mechanical properties of CNTs in epoxy resin (EP) coatings have been improved by the integration of zirconium disulfide (ZrS2) and 2-amino−5-(4-methoxyphenyl)−1, 3, 4-thiadiazole (AMPT) for surface modification based on CNTs. The structural, morphological, and dielectric behaviors of the films were characterized for the different formulations of coatings such as EP, EP/CNTs, EP-AMPT/CNTs, EP-CNTs/ZrS2, and EP-AMPT/CNTs-ZrS2 by means of SEM/EDX, TEM, TGA/XRD, XPS, XRD, and contact angle (CA) measurement. As a result, with the addition of only 0.3% AMPT/CNTs-ZrS2, the dielectric constant of EP was increased by 87-fold at 1 Hz. The electrochemical techniques and mechanical testing confirmed that AMPT/CNTs-ZrS2 composite exhibit enhanced anticorrosive and mechanical performance of the EP coating. Superior hydrophobic property of EP-AMPT/CNTs-ZrS2 is confirmed by its WCA of 161º. Furthermore, the resistance of the EP-AMPT/CNTs-ZrS2 was found to be much higher (20.870 MΩ.cm2)] than that of the pure EP (0.112 MΩ.cm2) and the microhardness and tensile strength of EP-AMPT/CNTs-ZrS2 were increased sharply. Therefore, the newly developed EP-AMPT/CNTs-ZrS2 nanocomposite could act as the vital material for coating AA8014 aluminum alloy used in aerospace applications.

Effect of Surface-Modified Nanosilicas on the Electrical Breakdown Strength in Epoxy Nanocomposites

Hydrophilic surface of fumed nanosilica was treated with a trimethylsilane coupling agent to achieve its hydrophobic surface, and the surface modification was confirmed by thermogravimetric weight loss and increasing contact angle of water droplet. The effects of the surface-modified nanosilica content on the electrical and mechanical properties of epoxy nanocomposites were studied to apply to the insulators for heavy electrical equipment. Epoxy nanocomposites were prepared by mixing epoxy base resin/curing agent/accelerator/trimethylsilane-modified nanosilica in the weight ratio of 100:80:1:0–7 g. High-voltage direct current breakdown strength increased with increasing modified nanosilica content. High-voltage alternating current breakdown strength was maximum when the nanosilica content was 1 phr (part per one hundred of epoxy resin), and thereafter, the value gradually decreased as the nanosilica content increased. Tensile strength of epoxy nanocomposite with trimethylsilane-modified nanosilica (7 phr) is 78.76 MPa, which is 20% higher than that of neat epoxy resin. The dielectric permittivity increases with increasing amount of the trimethylsilane-modified nanosilica.

Effect of adsorption, hardener, and temperature on mechanical properties of epoxy nanocomposites with functionalized graphene: A molecular dynamics study

Investigating Epoxy/hardener ratio and adsorption rate in epoxy/graphene oxide nanocomposites is of great importance, since these values can affect on the mechanical properties of the nanocomposite. In this study, molecular dynamics simulation was used to investigate and compare the mechanical properties of epoxy/graphene and graphene oxide nanocomposites (EPON 828, EPON 862, Epoxy Novolac, and Cycloaliphatic Epoxy with GNs and GO). Also, the effect of different weight percentages of graphene oxide (0,1,3 and 5 wt %), different weight percentages of epoxy compared to hardener, adsorption rate, and different temperatures were studied. The results showed that increasing the weight percentage of graphene oxide in epoxy matrices improved the adsorption rate between Epoxy/GO and the strength of nanocomposites. In addition, the amount of Young's modulus slightly decreased with increasing the temperature. Besides, the highest amount of Young modulus was obtained by increasing the weight percentage of epoxy to hardener at 63:37 wt %. Moreover, by comparing the mechanical properties of epoxy nanocomposites at 5 wt % graphene oxide, the highest Young modulus were found to be related to Novolac/GO 4.27 Gpa and EPON 862/GO 4.24 Gpa. This study contributes to a more comprehensive understanding on the behavior of the mechanical properties of epoxy/graphene oxide nanocomposites.

Static and dynamic mechanical properties of epoxy nanocomposites reinforced by hybridization with carbon nanofibers and block ionomers

Epoxy (EP) is widely used in many engineering applications, however, its inherent brittleness limits their impact resistance. Conventional toughening agents usually lead to compromised compressive strength. In this study, a ternary composite with epoxy as matrix mixed with sulfonated polystyrene-block-poly (ethylene-co-butylene)-block-polystyrene (SSEBS) and functionalized carbon nanofibers (CNFs) was reported. The quasi-static and dynamic compression characteristics of EP/SSEBS/CNFs composites at different loading rates (0.003–3600 s−1) are studied by means of a universal testing machine and split Hopkinson pressure bar (SHPB), respectively. The results show that the Young’s modulus, yield strength, compressive strength and failure strain of EP/SSEBS/CNFs composites with 0.75 wt% CNFs are all higher than those of EP at high strain rates. Among them, at a strain rate of 3600 s−1, the increase of Young’s modulus and compressive strength reaches 57% and 195.5%, respectively. Compared with EP, EP/SSEBS/CNFs composites exhibits more significant strain rate effect and strain hardening effect. Moreover, the large deformation ability of SSEBS, the bridging effect of CNF and the excellent interfacial properties between the hybrids and the EP matrix are found to be the main reasons for realizing the reinforcement and toughening of EP composites.

Highly dispersed aramid nanofiber-reinforced epoxy nanocomposites by the sequential solvent-exchange method

Aramid nanofibers have recently been used as novel reinforcing materials to overcome the limitations of epoxy resin because of their superior strength and toughness. Until now, aramid nanofibers were hybridized into the epoxy resin by adding water into an aramid nanofiber solution to obtain free-standing powders. Unfortunately, such a water-based method for inducing the gelation hinders high-level dispersion due to the re-agglomeration of the nanofibers by protonation. This study presents a novel technique utilizing a solvent-exchange method to maximize the dispersion degree of aramid nanofibers, thereby increasing the mechanical properties of epoxy nanocomposites. The mechanical properties of aramid nanofiber-reinforced epoxy nanocomposites by the solvent-exchange method were improved significantly (3.4 GPa in Young’s modulus and 90.0 MPa in tensile strength – improvements of 28.8% and 27.7%, respectively) although a high viscosity epoxy resin (bisphenol-A type) was considered. Therefore, the suggested solvent-exchange method is an efficient manufacturing process to produce highly dispersed aramid nanofiber/epoxy nanocomposites.

Effects of various functional groups in graphene on the tensile and flexural properties of epoxy nanocomposites: a comparative study

In this article, we investigated the effects of different functional groups in graphene on the mechanical performance of epoxy nanocomposites fabricated using the in-situ polymerization method. This study considered pristine graphene and three different varieties of functionalized graphene (–NH2, –COOH, and –OH) with varying weight percent (i.e., 0.25, 0.5, and 1.0 wt%). The functional groups grafted of graphene have been confirmed through Fourier transforms infrared (FTIR) spectra. Microstructural features and fracture surfaces were also examined by field-emission scanning electron microscopy with energy-dispersive X-ray spectroscopy. In comparison to pure epoxy, –OH functionalized graphene/epoxy nanocomposites showed a maximum improvement of 37.24% in tensile strength and 38.05% in flexural strength. The improved mechanical properties of epoxy nanocomposites were attributed to homogeneous dispersion, graphene bridging, and better interfacial contact between epoxy and graphene. HIGHLIGHTS The effect of pristine and functionalized graphene on the mechanical properties of epoxy nanocomposites was studied. Nanocomposites were fabricated for three different wt% (0.25, 0.5, and 1.0) of graphene nanofillers. Field emission scanning electron microscopy (FE-SEM) with EDX was used to examine the microstructural features of fractured surfaces. Graphene enhanced the mechanical properties of epoxy nanocomposites.

Mechanical properties of epoxy nanocomposites added with fullerene and milled-graphite nanoparticles: A comparative study

In the present work, a comparative study has been made on epoxy nanocomposite samples reinforced with 0.5 wt% of Fullerene (C60) and milled graphite nanoparticles (GrNPs). Both the nano reinforcements were analyzed under FESEM to assess their morphology. FESEM study reveals the spherical-shaped morphology of C60 with fewer defects, whereas GrNPs are found as aggregated with porous structures consisting of stacked and randomly oriented planes. The major challenges to fabricating epoxy nanocomposites with these nano reinforcements are discussed here with the possible remedies. With the aid of a mechanical stirrer, 0.5 wt% percent of C60 and GrNPs are dispersed separately into the viscous epoxy resin followed by vacuum degassing to remove the entrapped air. The degassed mixtures are then poured into a silicone mold followed by room temperature curing to fabricate the test specimens following ASTM standards. The test findings show that adding 0.5 wt% of C60 to the epoxy system increases the tensile strength, Young's modulus, and fracture toughness for the resulting epoxy nanocomposite by 13 %, 16.5 %, and 16 %, respectively, compared to the neat epoxy system. However, adding 0.5 wt% of GrNPs to the epoxy system increases strength and modulus by 2 % and 7 %, respectively, while depressing fracture toughness by 43 %. These findings informed us that pristine C60 are better reinforcement to strengthen epoxy resin compared to the pristine aggregated GrNPs, which rises the stress concentration effect around the reinforcement and initiates micro-cracks within the resin system thereby reducing the fracture toughness

Influence of carbon nanotubes, resin matrix and technology of mixture homogenization on ablative and dynamic mechanical properties of epoxy nanocomposites

The present work investigates the thermo-protective ablative and dynamic mechanical properties of two kinds of epoxy resins modified with carbon nanotubes (1 vol% or 5 vol% of CNT) and homogenized mechanically or ultrasonically. The samples have been subjected to combustion gases at a temperature above 1900 °C during 120 s. The best thermal protective properties were exhibited by the composites made by epoxy resin called Epidian 52 (cross-linked by TFF - triethylenetetramine) and containing 5 vol% of CNT. Dynamic mechanical tests were performed by using a compression deformation mode and also a double-cantilever bending mode. In the compression mode, the highest value of the complex modulus M* = 1030 MPa and a very low value of the damping factor tan δ = 0.02 were shown by the composite mechanically homogenized (Epidian 601 + TFF + 5% CNT). In the double cantilever bending mode, the highest value of the modulus M* (i.e. 1250 MPa) was shown by the composite (Epidian 601 + TFF + 1% CNT) with tan δ = 0.05 and which was homogenized by ultrasounds.

Improved exfoliation of surface-functionalized graphene oxide by epoxy monomer and enhanced mechanical properties of epoxy nanocomposites

Improved exfoliation of surface-functionalized graphene oxide by epoxy monomer and enhanced mechanical properties of epoxy nanocomposites

The influence of CNT-doped carbon aerogels on microstructural, rheological and mechanical properties of epoxy nanocomposites

In this study, CNT-doped carbon aerogel (CNT-CA) and carbon aerogel (CA) were used in different weight ratios (0.1, 0.3, and 0.5 wt%) to reinforce epoxy (Ep) nanocomposites. The relationship between the aerogels’ structure deformation such as the average diameter, the total volume of pores, specific surface area, and interfacial (particle/matrix) interaction, distribution, rheological, mechanical, and thermal properties were investigated systematically. Also, the nanocomposites were investigated by ATR-FTIR, XRD, and Raman spectroscopy. In general, the fabricated nanocomposites showed enhanced properties compared to the neat epoxy which is attributed to the penetration of polymer chains into the porous three-dimensional structure of the distributed aerogels. This phenomenon resulted in a high filler/matrix interaction, resulted in a better load transfer. Ep/CNT-CA showed better properties than Ep/CA which is due to ultrahigh specific surface area in CNT-CA. The rheological analysis showed a significant change in behavior from a liquid-like state to a pseudo-solid state in Ep/CA0.3 and Ep/CNT-CA0.1. Mechanical and thermal investigations of nanocomposites showed 8–17% increment in young modulus, 39–52% in tensile strength, 47–69% in elongation at break, 28–53% in E′ at 40 °C, 2–6% in Tanδ, and 7–11 °C in Tmax (compared to the neat epoxy matrix).

Effects of nano reinforcing/matrix interaction on chemical, thermal and mechanical properties of epoxy nanocomposites

This article investigates the impact of addition various types of nanoparticles with different structural, dimensional, and morphological properties on the interphase region formed between the particle/matrix and the curing behavior of the epoxy affect the nanocomposite material properties. For this purpose, epoxy nanocomposites (NCs) were produced by adding multi-walled carbon nanotube (MWCNT) and alumina (Al2O3) nanoparticles (NPs) into the epoxy matrix at different rates (0.5–2.0 wt.%). The effects of the particle/matrix interaction on the properties of the composite have been revealed by chemical, thermal, mechanical analyzes and microstructure investigations. An increase in the absorption density, which reveals the physical interaction of nanoparticles with the epoxy matrix, was observed in Fourier-transform infrared spectroscopy. Absorption vibration peak intensities in nanocomposite samples were at most 1.0 wt.% Al2O3 and 1.25 wt.% CNT added nanocomposites. It was observed that the Tg value increased depending on the number of nanoparticles. The addition of Al2O3 increased Tg values more than CNT. Besides, the mechanical properties of NCs were determined by tensile tests. The highest increase in mechanical properties was achieved by adding 1.25 wt.% CNT and 1.0 wt.% Al2O3, respectively. Mechanical properties tended to decrease at higher addition rates. The shape, size, amount, and distribution of nanoparticles added into the epoxy matrix directly affected the NCs' properties. It has been determined that homogeneously dispersed spherical Al2O3 nanoparticles are more effective than fiber-shaped CNTs in the properties of NCs.

Study on the Synergies of Nanoclay and MWCNTs to the Flame Retardant and Mechanical Properties of Epoxy Nanocomposites

Modern flame retardants are organic compounds containing halogen or phosphorus groups and are not always well dispersed in polymers. Thus, by using a small amount of nanoclay and multiwalled carbon nanotubes (MWCNTs), they can significantly reduce the number of conventional flame retardant additives, making the material with optimal flame retardant properties. Conventional flame retardants always have some negative effects on the mechanical properties of the polymer substrate, so by using nanoclay and MWCNTs, those adverse effects can be minimized and overcome. In this work, in order to improve the mechanical properties and flame retardant of nanocomposite materials, nanoclay I.30E and MWCNTs are mixed into epoxy, with the selected percentage of 2% and 0.02% by weight, respectively, stirring mechanically for 7, 8, and 9 hours at 3000 rpm at 80°C, then performing ultrasonic vibration for 6 hours at 65°C.

Enhanced mechanical properties of epoxy nanocomposites with mildly surface-functionalized graphene oxide by tuned amine species

The surface functionalization of graphene oxide (GO) is always attractive in modulating the interfacial characteristics, improving the interfacial bonds and mechanical properties of epoxy-based nanocomposites. In this contribution, amine functionalized graphene oxide (AGO) samples were prepared through the surface functionalization of GO using m-xylylenediamine (m-XDA) and polyetheramine D230, respectively. Simultaneously, weakly oxidized and normally oxidized GO samples were both functionalized to obtain AGO samples with low and high amine grafting density. AGO/epoxy nanocomposites were fabricated and their mechanical properties at room temperature (RT) and liquid nitrogen temperature (LNT) were investigated. Interfacial characteristics of the nanocomposites were revealed through experimental and molecular dynamics (MD) simulation methods. It was found that m-XDA grafted GO (MAGO) showed better dispersion in the matrix and prominently higher efficiency in enhancing the mechanical properties of epoxy resin than D230 grafted GO (DAGO). MAGO nanocomposites exhibited tensile strength 18.1% and 11.3% higher than neat epoxy at RT and LNT, respectively. The result was highly consistent with the enhanced interfacial interaction energy between MAGO and epoxy compared to that between DAGO and epoxy as revealed by MD simulation. However, nanocomposites modified by AGO with improved amine grafting density didn’t show enhanced mechanical properties as expected from MD simulation.

Effect of different types of silica particles on dielectric and mechanical properties of epoxy nanocomposites

Polymer insulation is an integral part of electrical equipment. For an electrical insulation system, electrical, mechanical and thermal properties of polymer play a critical role in performance of insulation. Therefore, for reliable insulation system it is imperative to enhance and upgrade the insulating materials properties. In this context nanodielectrics materials can play a crucial role for next generation of insulating materials. Development of nanodielectrics materials with enhanced properties is a complex interplay between filler particle size, its functionalization and uniform dispersion in polymer matrix. In this paper, we report preparation of epoxy nanocomposites with silica particles having varying size and functionality. The epoxy nanocomposite composites were evaluated for their dielectric strength, dielectric dissipation and water absorption and impact properties. Our results shows improvement in dielectric and impact properties for epoxy nanocomposites with functionalized fumed silica nano-particles. Addition of colloidal silica did not show noticeable improvement in dielectric and mechanical properties. Our results for epoxy nanocomposite shows that enhancement of epoxy nanocomposite properties are function of particles size and chemical functionality of filler particles.

Effect of coactive influence of LDHs and PNCC on thermal and mechanical properties of epoxy resin

ABSTRACT The nanofiller improve the properties of the pristine polymer resins to the great extent. In present findings, the preparation of nanocomposites (epoxy/PNCC/LDHs) was done by the ‘Slurry-compounding method’. Precipitated nano-calcium carbonate (PNCC) were mixed with Layer double hydroxides (LDHs) in varying ratio and added to epoxy resin with constant stirring at room temperature. The degree of distribution of the nanofiller and the kind of polymeric nanocomposites formed was observed by Wide-angle X-ray Diffraction, and Scanning Electron Microscopy. The thermal and mechanical properties of epoxy nanocomposites were characterised by Thermogravimetric analysis and Universal Testing Machine, respectively. However, harmonisation and coactive influence of PNCC with LDHs showed a better effect on the mechanical and thermal properties of epoxy resin and offers superior mechanical and thermal properties as compared to pristine epoxy resin and two-component ( Epoxy/PNCC) nanocomposites.

Synergistic effects of graphene nanoplatelets and NH2-MWCNTs on cryogenic mechanical properties of epoxy nanocomposites

Fracture toughness (FT) and Tensile strength (TS) of epoxy reinforced amine-functionalized MWCNTs (A-MWCNTs)/graphene nanoparticles (GNPs) composites are investigated in cryogenic environment. Simplex centroid design is employed to decide the composition of samples. FT and TS of epoxy improved significantly on incorporating 0.25 wt% of either A-MWCNTs or GNPs, but increasing the content of nanofillers beyond 0.25% showed lower enhancement in the mechanical properties. Simultaneous addition of nanofillers in epoxy demonstrated synergistic effects, with the maximum FT (121%) and TS (132%) noticed for hybrid composite containing 0.17% of each nanofiller. It is attributed to the presence of well interconnected 3D network between nanofillers and epoxy, which yield uniform dispersion of nanofillers and strong adhesion between nanofillers and epoxy. Regression analysis suggested quadratic models for estimating FT and TS. Multiple response optimization yields the maximum FT (0.907 MPm1/2) and TS (20.6 MPa) for hybrid composite containing 99.67% epoxy, 0.17% A-MWCNTS and 0.16% GNPs.

A review on mechanical properties of epoxy nanocomposites

Epoxy resins have highly appreciable design flexibility, good mechanical, thermal, chemical properties and also compatible with a wide variety of reinforcement materials. These excellent properties make epoxy resin as a choice resin for many high-performance engineering applications. Despite their high performances, there are challenges and opportunities to improve further the performance and durability of epoxy composites. This paper presents a survey of the literature on epoxy nanocomposites and the influences of nanofillers on the mechanical properties of epoxy composites. Herein, various pivotal parameters affecting their mechanical properties including their morphology are discussed. This review will have a great impact on the field and will assist researchers in enhancing the mechanical properties of epoxy polymer composites by reinforcing nanofillers.