Structural and mechanical characterization of nanoclay-reinforced agarose nanocomposites

Li, Xiaodong; Gao, Hongsheng; Scrivens, Wally A.; Fei, Dongling; Thakur, V. M.; Sutton, Michael A.; Reynolds, Anthony P.; Myrick, Michael L.

doi:10.1088/0957-4484/16/10/006

Cited by 83 publications

(25 citation statements)

References 44 publications

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“…Unsurprisingly, both strain at break and toughness fall, apparently exponentially, with increasing mass fraction. This is often observed in nano filledelastomer composites [20,21,23]. The graphene contents required to decrease ε B and T by a factor of 100 are ~60wt% in each case.…”

Section: Mechanical Properties As a Function Of Graphene Contentmentioning

confidence: 77%

“…While addition of nano-fillers such as nanotubes, nanoclays, nanofibres etc to elastomers may result in increases in strength and stiffness, this is usually accompanied by reduction in ductility and toughness. [20][21][22][23] Thus, it will be critical to improve stiffness and strength at a faster rate than ductility and toughness are degraded. This has been attempted before by filling polyurethane (PU) with nanotubes.…”

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confidence: 99%

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Development of stiff, strong, yet tough composites by the addition of solvent exfoliated graphene to polyurethane

Khan

May

O’Neill

et al. 2010

Carbon

280

200

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Please cite this article as: Khan, U., May, P., O'Neill, A., Coleman, J.N., Development of stiff, strong, yet tough composites by the addition of solvent exfoliated graphene to polyurethane, Carbon (2010), doi: 10.1016/j.carbon. 2010.07.008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Development of stiff, strong, yet tough composites by the addition of solvent We have prepared graphene dispersions, stabilised by polyurethane in tetrahydrofuran and dimethylformamide. These dispersions can be drop-cast to produce free-standing composite films. The graphene mass fraction is determined by the concentration of dispersed graphene and can be controllably varied from 0% to 90%. Raman spectroscopy and Helium ion microscopy show the graphene to well-dispersed and well-exfoliated in the composites, even at mass fractions of 55%. On addition of graphene, the Young's modulus and stress at 3% strain increase by ×100, saturating at 1 GPa and 25 MPa respectively for mass fractions above 50wt%. While the ultimate tensile strength does not vary significantly with graphene content, the strain at break and toughness degrade heavily on graphene addition. Both these properties fall by ×1000 as the graphene content is increased to 90wt%. However, the rate of increase of Young's modulus and stress at 3% strain with mass fraction is greater than the rate of decrease of ductility and toughness.This makes it possible to prepare composites with high modulus, stress at low strain and ultimate tensile strength as well as relatively high toughness and ductility. This could lead to new materials that are stiff, strong and tough. With this in mind, we propose a different approach. Rather than reinforcing thermoplastics, we suggest that graphene might make an impact reinforcing elastomers.Reinforcement mechanisms in elastomeric composites are more complex than in thermoplastic based composites, a fact that may circumvent the poor stress transfer described above. Hard thermoplastics are characterised by relatively high stiffness and strength but low ductility and toughness (work done to fracture). Conversely, elastomers are characterised by low stiffness and low stress at low strain but high ductility and toughness. We propose that addition of graphene to elastomers could result in a material with positive elements of both hard thermoplastics and elastomers: high stiffness and strength yet relatively large ductility and toughness. Such materials would be useful in a range of applications.For such composites to have the properties outlined, a delicate balance must be maintained. While addition of nano-fillers such as nanotubes, nano...

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Section: Mechanical Properties As a Function Of Graphene Contentmentioning

confidence: 77%

mentioning

confidence: 99%

Development of stiff, strong, yet tough composites by the addition of solvent exfoliated graphene to polyurethane

Khan

May

O’Neill

et al. 2010

Carbon

280

200

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“…[8a,9] Agarose, a polysaccharide, has been chosen as the proton reservoir needed for photochromic response and the matrix to disperse EuSiWMo because of its good film-forming ability and its excellent optical transparency and mechanical strength. [10] The chemical structure of agarose is also shown in Scheme 1.…”

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confidence: 99%

Reversible Luminescent Switching in a [Eu(SiW₁₀MoO₃₉)₂]¹³⁻‐Agarose Composite Film by Photosensitive Intramolecular Energy Transfer

Wang

Zhang

et al. 2009

Advanced Materials

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Transparent, flexible, self‐supporting EuSiWMo/agarose composite films are fabricated by a combination of hydrogel chemistry and a casting technique, and present reversible, high‐contrast luminescence photoswitching modulated by inorganic photochromic components through intramolecular resonance‐energy transfer. Two‐dimensional recording employing the luminescence as read‐out signals is accomplished in this novel recording medium.

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“…The above results were obtained for steels, polymers, titanium and its alloys and aluminum alloys. It seems appropriate to apply the rules in Figures 2 and 3 and Equations (39), (40), (52) to specific polymers, composites and natural materials like seashells for example, which are characterized by high strength and wear resistance [55][56][57][58][59]. Such an application could be realized based on the model of many contact interactions between the elements of the multibody tribo-fatigue system described in [5,60].…”

Section: Experimental Verificationmentioning

confidence: 99%

A Model of Mechanothermodynamic Entropy in Tribology

Sosnovskiy

Sherbakov

2017

Entropy

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A brief analysis of entropy concepts in continuum mechanics and thermodynamics is presented. The methods of accounting for friction, wear and fatigue processes in the calculation of the thermodynamic entropy are described. It is shown that these and other damage processes of solids are more adequately described by tribo-fatigue entropy. It was established that mechanothermodynamic entropy calculated as the sum of interacting thermodynamic and tribo-fatigue entropy components has the most general character. Examples of usage (application) of tribo-fatigue and mechanothermodynamic entropies for practical analysis of wear and fatigue processes are given.Keywords: entropy; mechanothermodynamics; tribo-fatigue; tribology; fatigue; damage Thermodynamic EntropyThe following functions are used to describe the state of thermodynamic systems [1]:where temperature T, volume V, and number of moles of chemical components N k are the macroscopic state variables. In the general case of an open system, the change dU of internal energy U is presented [1] as:where dQ is the amount of heat; dA is the amount of mechanical energy; dU sub is the amount of substance, which the system exchanged with the environment for a time interval dt; p is the pressure; the µ k 's are the chemical potentials. Planck especially emphasized that dU in Equation (2) is an infinitely small difference, whereas dQ, dA, and dU sub are the infinitely small amounts. It follows from (2) that entropy S change in a thermodynamic system (subscript T) is: Abstract: A brief analysis of entropy concepts in continuum mechanics and thermodynamics is presented. The methods of accounting for friction, wear and fatigue processes in the calculation of the thermodynamic entropy are described. It is shown that these and other damage processes of solids are more adequately described by tribo-fatigue entropy. It was established that mechanothermodynamic entropy calculated as the sum of interacting thermodynamic and tribofatigue entropy components has the most general character. Examples of usage (application) of tribo-fatigue and mechanothermodynamic entropies for practical analysis of wear and fatigue processes are given.

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Structural and mechanical characterization of nanoclay-reinforced agarose nanocomposites

Cited by 83 publications

References 44 publications

Development of stiff, strong, yet tough composites by the addition of solvent exfoliated graphene to polyurethane

Development of stiff, strong, yet tough composites by the addition of solvent exfoliated graphene to polyurethane

Reversible Luminescent Switching in a [Eu(SiW₁₀MoO₃₉)₂]¹³⁻‐Agarose Composite Film by Photosensitive Intramolecular Energy Transfer

A Model of Mechanothermodynamic Entropy in Tribology

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Structural and mechanical characterization of nanoclay-reinforced agarose nanocomposites

Cited by 83 publications

References 44 publications

Development of stiff, strong, yet tough composites by the addition of solvent exfoliated graphene to polyurethane

Development of stiff, strong, yet tough composites by the addition of solvent exfoliated graphene to polyurethane

Reversible Luminescent Switching in a [Eu(SiW10MoO39)2]13−‐Agarose Composite Film by Photosensitive Intramolecular Energy Transfer

A Model of Mechanothermodynamic Entropy in Tribology

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Reversible Luminescent Switching in a [Eu(SiW₁₀MoO₃₉)₂]¹³⁻‐Agarose Composite Film by Photosensitive Intramolecular Energy Transfer