Impressive Fatigue Life and Fracture Toughness Improvements in Graphene Oxide/Epoxy Composites

Bortz, Daniel R.; Heras, Erika Garcia; Martı́n-Gullón, Ignacio

doi:10.1021/ma201563k

Cited by 466 publications

(297 citation statements)

References 30 publications

(56 reference statements)

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“…Detailed reviews on graphene research have been published [5,6], specifically regarding its use as polymer reinforcement. The majority of the early research was based on graphene oxide [7][8][9][10], which can be easily exfoliated and dispersed in epoxy due to the attached functional groups. However, these functional groups reduce the mechanical properties and their weight causes wrinkling of the graphene sheets [11].…”

Section: Introductionmentioning

confidence: 99%

Graphene nanoplatelet-modified epoxy: effect of aspect ratio and surface functionality on mechanical properties and toughening mechanisms

2016

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Graphene has the potential to act as a high-performance reinforcement for adhesives or fibre composites when combined with epoxy polymer. However, it is currently mostly available not as single high aspect ratio sheets but as graphene nanoplatelets (GNPs), comprised of stacks of graphene sheets.Graphene nanoplatelets of a range of lateral size, thickness, aspect ratio and surface functionality were used to modify an anhydride cured epoxy polymer.The morphology, mechanical properties and toughening mechanisms of these modified epoxies were investigated. The GNPs were sonicated in tetrahydrofuran (THF) or n-methyl-pyrrolidone (NMP) to facilitate dispersion in the epoxy. The use of THF resulted in large agglomerates, whereas more finely dispersed stacks of GNPs were observed for NMP. The maximum values of modulus (3.6 GPa at 1 wt%) and fracture energy (343 J/m 2 at 2 wt%) were * Corresponding author, Tel.: +44 20 7594 7149Email address: a.c.taylor@imperial.ac.uk (A. C. Taylor) April 11, 2016 measured for the epoxy modified with an intermediate platelet size of approximately 4 µm, compared to 2.9 GPa and 96 J/m 2 respectively for the unmodified epoxy. The Young's modulus was highly dependent on the dispersion quality, whereas the fracture energy was independent of the degree of GNP dispersion. The larger agglomerates of the GNPs which were dispersed in THF toughened the epoxy by crack deflection, whereas the GNPs dispersed in NMP showed platelet debonding, pull-out and plastic void growth of the epoxy. This work indicates that reinforcement and toughening can be achieved at much lower contents than for conventional modifiers. Further, achieving a good dispersion is crucial to the engineering application of these materials, and intermediate-sized graphene achieves the best balance of properties. Preprint submitted to Journal of Materials Science

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Section: Introductionmentioning

confidence: 99%

Graphene nanoplatelet-modified epoxy: effect of aspect ratio and surface functionality on mechanical properties and toughening mechanisms

2016

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“…In contrast, the addition of graphene enhances the impact resistance of epoxy and here too, the degree of enhancement is proportional to the graphene loading. The observed effects of graphene on the bending and the impact resistance are attributed to the increase in stiffness and toughness of the epoxy composite with graphene loading, which was also reported [26][27][28][29], which enhances the resistance to sudden deformation and reduces the elasticity of the epoxy coating.…”

Section: Flexibility and Impact Resistancementioning

confidence: 58%

Enhanced protective properties and UV stability of epoxy/graphene nanocomposite coating on stainless steel

Alhumade

Elkamel

et al. 2016

Express Polym. Lett.

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Abstract. Epoxy-Graphene (E/G) nanocomposites with different loading of graphene were prepared via in situ prepolymerization and evaluated as protective coating for Stainless Steel 304 (SS304). The prepolymer composites were spin coated on SS304 substrates and thermally cured. Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM) were utilized to examine the dispersion of graphene in the epoxy matrix. Epoxy and E/G nanocomposites were characterized using X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) techniques and the thermal behavior of the prepared coatings is analyzed using Thermogravimetric analysis (TGA) and Differential scanning calorimetry (DSC). The corrosion protection properties of the prepared coatings were evaluated using Electrochemical Impedance Spectroscopy (EIS) and Cyclic Voltammetry (CV) measurements. In addition to corrosion mitigation properties, the long-term adhesion performance of the coatings was evaluated by measuring the adhesion of the coatings to the SS304 substrate after 60 days of exposure to 3.5 wt% NaCl medium. The effects of graphene loading on the impact resistance, flexibility, and UV stability of the coating are analyzed and discussed. SEM was utilized to evaluate post adhesion and UV stability results. The results indicate that very low graphene loading up to 0.5 wt % significantly enhances the corrosion protection, UV stability, and impact resistance of epoxy coatings.

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“…The results obtained indicate that atomistic modeling approach is more accurate than micromechanics approach. The decrease in elastic constants with increasing graphene content can be attributed to the inevitable possibility of agglomeration and void content because of intergraphene layer gap and graphene-polymer gap [141].…”

Section: Weight Fractionmentioning

confidence: 99%

Modeling and Simulation of Graphene Based Polymer Nanocomposites: Advances in the Last Decade

Atif¹,

Inam²

2016

Graphene

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Modeling and simulation allow methodical variation of material properties beyond the capacity of experimental methods. The polymers are one of the most commonly used matrices of choice for composites and have found applications in numerous fields. The stiff and fragile structure of monolithic polymers leads to the innate cracks to cause fracture and therefore the engineering applications of monolithic polymers, requiring robust damage tolerance and high fracture toughness, are not ubiquitous. In addition, when "many-parts" cling together to form polymers, a labyrinth of molecules results, which does not offer to electrons and phonons a smooth and continuous passageway. Therefore, the monolithic polymers are bad conductors of heat and electricity. However, it is well established that when polymers are embedded with suitable entities especially nano-fillers, such as metallic oxides, clays, carbon nanotubes, and other carbonaceous materials, their performance is propitiously improved. Among various additives, graphene has recently been employed as nano-filler to enhance mechanical, thermal, electrical, and functional properties of polymers. In this review, advances in the modeling and simulation of grapheme based polymer nanocomposites will be discussed in terms of graphene structure, topographical features, interfacial interactions, dispersion state, aspect ratio, weight fraction, and trade-off between variables and overall performance.

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Impressive Fatigue Life and Fracture Toughness Improvements in Graphene Oxide/Epoxy Composites

Cited by 466 publications

References 30 publications

Graphene nanoplatelet-modified epoxy: effect of aspect ratio and surface functionality on mechanical properties and toughening mechanisms

Graphene nanoplatelet-modified epoxy: effect of aspect ratio and surface functionality on mechanical properties and toughening mechanisms

Enhanced protective properties and UV stability of epoxy/graphene nanocomposite coating on stainless steel

Modeling and Simulation of Graphene Based Polymer Nanocomposites: Advances in the Last Decade

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