Hierarchical Structure and Properties of Graphene Oxide Papers

2013 ◽  
Vol 80 (4) ◽  
Author(s):  
Charles D. Wood ◽  
Marc J. Palmeri ◽  
Karl W. Putz ◽  
Zhi An ◽  
SonBinh T. Nguyen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Structural Feature ◽  
Uniaxial Tension ◽  
Hierarchical Structure ◽  
Mechanical Response ◽  
Structure And Properties ◽  
Fracture Surfaces ◽  
High Stiffness ◽  
Significant Attention

The mechanical properties of graphene oxide papers have attracted significant attention in recent years due to their high stiffness and tough behavior. While the structural feature most commonly characterized is the nanosheet spacing, there is a hierarchical structure, which is likely responsible for the impressive mechanical properties. In this paper, we examine the structure of graphene oxide papers on several length scales using novel techniques to distinguish between lamellae and a newly defined feature, termed “super-lamellae.” The differentiation between these intermediate features provides context to the previously observed mechanical response and fracture surfaces of graphene oxide papers, particularly under uniaxial tension.

Relationships between hierarchical structure and properties in macromolecular systems

1987 ◽  
Vol 45 ◽  
pp. 440-443
Author(s):  
E. Baer
Keyword(s):  
Uniaxial Tension ◽  
Hierarchical Structure ◽  
Inorganic Material ◽  
Hierarchical Structures ◽  
Bone Collagen ◽  
Structure And Properties ◽  
Connective Tissues ◽  
Scale Level ◽  
Fibrous Protein ◽  
Macromolecular Systems

The most advanced macromolecular materials are found in plants and animals, and certainly the connective tissues in mammals are amongst the most advanced macromolecular composites known to mankind. The efficient use of collagen, a fibrous protein, in the design of both soft and hard connective tissues is worthy of comment. Very crudely, in bone collagen serves as a highly efficient binder for the inorganic hydroxyappatite which stiffens the structure. The interactions between the organic fiber of collagen and the inorganic material seem to occur at the nano (scale) level of organization. Epitatic crystallization of the inorganic phase on the fibers has been reported to give a highly anisotropic, stress responsive, structure. Soft connective tissues also have sophisticated oriented hierarchical structures. The collagen fibers are “glued” together by a highly hydrated gel-like proteoglycan matrix. One of the simplest structures of this type is tendon which functions primarily in uniaxial tension as a reinforced elastomeric cable between muscle and bone.

scholarly journals Multiscale Modeling of Epoxy-Based Nanocomposites Reinforced with Functionalized and Non-Functionalized Graphene Nanoplatelets

Polymers ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1958
Author(s):  
Hashim Al Mahmud ◽  
Matthew S. Radue ◽  
Sorayot Chinkanjanarot ◽  
Gregory M. Odegard
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Aspect Ratio ◽  
Mechanical Response ◽  
Nanocomposite Materials ◽  
Graphene Nanoplatelets ◽  
Pristine Graphene ◽  
Functionalized Graphene ◽  
Functionalized Graphene Oxide ◽  
The Impact

The impact on the mechanical properties of an epoxy resin reinforced with pristine graphene nanoplatelets (GNP), highly concentrated graphene oxide (GO), and functionalized graphene oxide (FGO) has been investigated in this study. Molecular dynamics (MD) using a reactive force field (ReaxFF) has been employed in predicting the effective mechanical properties of the interphase region of the three nanocomposite materials at the nanoscale level. A systematic computational approach to simulate the reinforcing nanoplatelets and probe their influence on the mechanical properties of the epoxy matrix is established. The modeling results indicate a significant degradation of the in-plane elastic Young’s (decreased by ~89%) and shear (decreased by ~72.5%) moduli of the nanocomposite when introducing large amounts of oxygen and functional groups to the robust sp2 structure of the GNP. However, the wrinkled morphology of GO and FGO improves the nanoplatelet-matrix interlocking mechanism, which produces a significant improvement in the out-of-plane shear modulus (increased by 2 orders of magnitudes). The influence of the nanoplatelet content and aspect ratio on the mechanical response of the nanocomposites has also been determined in this study. Generally, the predicted mechanical response of the bulk nanocomposite materials demonstrates an improvement with increasing nanoplatelet content and aspect ratio. The results show good agreement with experimental data available from the literature.

A pH and Electric Responsive Graphene Oxide Based Composite Hydrogel

2012 ◽  
Vol 430-432 ◽  
pp. 327-330 ◽  
Author(s):  
Yong Qiang He ◽  
Hua Bin Chen ◽  
Hong Sun ◽  
Xiao Dong Wang ◽  
Jian Ping Gao
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Graphene Oxide ◽  
Electric Field ◽  
Structure And Properties ◽  
Composite Hydrogels ◽  
External Stimuli ◽  
Scanning Electron

The pH and electric responsive composite hydrogels were prepared byin situpolymerization in the presence of graphene oxide (GO). Their structure and properties were characterized by scanning electron microscopy, Raman microscopy and mechanical testing. The results indicate that the GO is evenly dispersed in the composite hydrogels and the mechanical properties of the GO based composite hydrogels are significantly improved. Most importantly, the composite hydrogels were responsive to external stimuli such as pH and electric field.

scholarly journals Deformation micromechanisms of collagen fibrils under uniaxial tension

2009 ◽  
Vol 7 (46) ◽  
pp. 839-850 ◽  
Author(s):  
Yuye Tang ◽  
Roberto Ballarini ◽  
Markus J. Buehler ◽  
Steven J. Eppell
Keyword(s):  
Mechanical Properties ◽  
Uniaxial Tension ◽  
Structural Engineering ◽  
Mechanical Response ◽  
Structural Parameters ◽  
Finite Size ◽  
Collagen Fibrils ◽  
Deformation Mechanisms ◽  
Collagen Molecule ◽  
Intermediate Structure

Collagen, an essential building block of connective tissues, possesses useful mechanical properties due to its hierarchical structure. However, little is known about the mechanical properties of collagen fibril, an intermediate structure between the collagen molecule and connective tissue. Here, we report the results of systematic molecular dynamics simulations to probe the mechanical response of initially unflawed finite size collagen fibrils subjected to uniaxial tension. The observed deformation mechanisms, associated with rupture and sliding of tropocollagen molecules, are strongly influenced by fibril length, width and cross-linking density. Fibrils containing more than approximately 10 molecules along their length and across their width behave as representative volume elements and exhibit brittle fracture. Shorter fibrils experience a more graceful ductile-like failure. An analytical model is constructed and the results of the molecular modelling are used to find curve-fitted expressions for yield stress, yield strain and fracture strain as functions of fibril structural parameters. Our results for the first time elucidate the size dependence of mechanical failure properties of collagen fibrils. The associated molecular deformation mechanisms allow the full power of traditional material and structural engineering theory to be applied to our understanding of the normal and pathological mechanical behaviours of collagenous tissues under load.

Enhancing mechanical properties of consolidated nanocrystalline copper powder by means of equal channel angular pressing method

2021 ◽  
pp. 030932472199330
Author(s):  
Ceren Gode
Keyword(s):  
Mechanical Properties ◽  
Equal Channel Angular Pressing ◽  
Mechanical Response ◽  
Bimodal Distribution ◽  
Large Strains ◽  
Pressing Method ◽  
Nanocrystalline Copper ◽  
Angular Pressing ◽  
Ultrafine Grained ◽  
Significant Attention

Ultrafine grained and nanostructured materials have drawn significant attention due to their unusual mechanical behavior. The purpose of this research was to study the mechanical properties and microstructural evolution of nanocrystalline copper obtained through a bottom-up procedure of nanoparticle consolidation by equal channel angular pressing (ECAP). ECAP was approved to be a proper approach to produce comparatively big nanocrystalline consolidates including acceptable mechanical properties. The effects of ECAP pass numbers on consolidation achievement were also assessed. The quite large strains observed in the samples were associated with the bimodal distribution condition of grain sizes. The present work reveals that ECAP consolidation of nanoparticles presents a novel opportunity to investigate the mechanical response of nanostructured metals and alloys moreover it gives a chance to the production of unique kinds of bulk materials for useful purposes.

Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

2020 ◽  
pp. 39-48
Author(s):  
B. O. Bolshakov ◽  
◽  
R. F. Galiakbarov ◽  
A. M. Smyslov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Boron Nitride ◽  
Grain Boundary ◽  
Bending Strength ◽  
Physical And Mechanical Properties ◽  
Operating Conditions ◽  
Structure And Properties ◽  
Steam Turbines ◽  
Friction Forces ◽  
Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

scholarly journals Water lubrication of graphene oxide-based materials

Friction ◽  
2021 ◽  
Author(s):  
Shaoqing Xue ◽  
Hanglin Li ◽  
Yumei Guo ◽  
Baohua Zhang ◽  
Jiusheng Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Lubrication Theory ◽  
Lubricant Additives ◽  
Water Lubrication ◽  
Broad Application ◽  
Water Dispersibility ◽  
Metal Processing ◽  
The Relationship ◽  
Ph Concentration

AbstractWater is as an economic, eco-friendly, and efficient lubricant that has gained widespread attention for manufacturing. Using graphene oxide (GO)-based materials can improve the lubricant efficacy of water lubrication due to their outstanding mechanical properties, water dispersibility, and broad application scenarios. In this review, we offer a brief introduction about the background of water lubrication and GO. Subsequently, the synthesis, structure, and lubrication theory of GO are analyzed. Particular attention is focused on the relationship between pH, concentration, and lubrication efficacy when discussing the tribology behaviors of pristine GO. By compounding or reacting GO with various modifiers, amounts of GO-composites are synthesized and applied as lubricant additives or into frictional pairs for different usage scenarios. These various strategies of GO-composite generate interesting effects on the tribology behaviors. Several application cases of GO-based materials are described in water lubrication, including metal processing and bio-lubrication. The advantages and drawbacks of GO-composites are then discussed. The development of GO-based materials for water lubrication is described including some challenges.

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