scholarly journals Mechanical Properties of Graphene Oxide Coupled by Multi-Physical Field: Grain Boundaries and Functional Groups

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 62
Author(s):  
Xu Xu ◽  
Zeping Zhang ◽  
Wenjuan Yao
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Grain Boundaries ◽  
Functional Groups ◽  
Oxygen Content ◽  
Tensile Fracture ◽  
Hydroxyl Groups ◽  
Molecular Configuration ◽  
Spatial Design ◽  
Out Of Plane

Graphene and graphene oxide (GO) usually have grain boundaries (GBs) in the process of synthesis and preparation. Here, we “attach” GBs into GO, a new molecular configuration i.e., polycrystalline graphene oxide (PGO) is proposed. This paper aims to provide an insight into the stability and mechanical properties of PGO by using the molecular dynamics method. For this purpose, the “bottom-up” multi-structure-spatial design performance of PGO and the physical mechanism associated with the spatial structure in mixed dimensions (combination of sp2 and sp3) were studied. Also, the effect of defect coupling (GBs and functional groups) on the mechanical properties was revealed. Our results demonstrate that the existence of the GBs reduces the mechanical properties of PGO and show an “induction” role during the tensile fracture process. The presence of functional groups converts in-plane sp2 carbon atoms into out-of-plane sp3 hybrid carbons, causing uneven stress distribution. Moreover, the mechanical characteristics of PGO are very sensitive to the oxygen content of functional groups, which decrease with the increase of oxygen content. The weakening degree of epoxy groups is slightly greater than that of hydroxyl groups. Finally, we find that the mechanical properties of PGO will fall to the lowest values due to the defect coupling amplification mechanism when the functional groups are distributed at GBs.

Enhancement of Hydrophobility and Thermal Property of Graphene Oxide by Paratoluidine Chemical Functionalization

2014 ◽  
Vol 809-810 ◽  
pp. 243-247
Author(s):  
Zhi Jia Luo ◽  
Hong Zhang Geng ◽  
Song Ting Zhang ◽  
Bao Tan Du ◽  
Xing Zhang ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Graphene Oxide ◽  
Thermal Property ◽  
Functional Groups ◽  
Drug Delivery Systems ◽  
Graphite Powder ◽  
Hydroxyl Groups ◽  
Chemical Functionalization ◽  
Hummers Method ◽  
Modified Hummers Method

Graphene oxide (GO) is typically synthesized by graphite powder under strong oxidizing reaction, possessing with the same set of functional groups: epoxy and hydroxyl in basal plane and carboxyl and hydroxyl groups existence on the flake edges which endow GO with amphipathy. GO and its functionalized derivatives have been successfully tested in many domains, such as polymer composites, biosensors, drug delivery systems, etc. In this paper, GO was prepared by a modified Hummers method employing improved process (preparation and separation), aiming at industrialization with the lowest cost. Moreover, some novel functional groups with different properties were controlled chemically grafted onto GO to modify the wettability and reaction activity with other materials. The hydrophobicity and the thermal property of graphene oxide were enhanced by chemical functionalization.

Ammonia Dissociation on Graphene Oxide: An Ab Initio Density Functional Theory Calculation

2015 ◽  
Vol 229 (7-8) ◽  
Author(s):  
Liangliang Huang ◽  
Keith E. Gubbins
Keyword(s):  
Density Functional Theory ◽  
Graphene Oxide ◽  
Ab Initio ◽  
Functional Groups ◽  
Density Functional ◽  
Density Functional Theory Calculation ◽  
Exothermic Reaction ◽  
Density Functional Theory Method ◽  
Hydroxyl Groups ◽  
Functional Theory

AbstractInteractions of ammonia and water with the oxygen-containing functional groups of graphite oxide have been studied by ab initio density functional theory method. The results show that ammonia can dissociate on the carboxyl, epoxy and hydroxyl groups. The dissociation on the epoxy group is an exothermic reaction with a small activation energy barrier. Water is found to form a hydrogen bond with the carboxyl, epoxy and hydroxyl groups, and thus will block ammonia from interacting with those functional groups. The results in this work provide a fundamental understand of previous experiments about ammonia adsorption on graphene oxide materials.

scholarly journals The effects of hydroxide and epoxide functional groups on the mechanical properties of graphene oxide and its failure mechanism by molecular dynamics simulations

RSC Advances ◽  
2020 ◽  
Vol 10 (49) ◽  
pp. 29610-29617 ◽  
Author(s):  
Yunjin Sun ◽  
Xing Tang ◽  
Hongwei Bao ◽  
Zhi Yang ◽  
Fei Ma
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Graphene Oxide ◽  
Molecular Dynamics Simulations ◽  
Failure Mechanism ◽  
Functional Groups ◽  
Nano Composites ◽  
Interface Adhesion ◽  
Dynamics Simulations

Graphene oxide (GO) could be assembled via amphiphilic interface adhesion into nano-composites.

scholarly journals Mechanical properties of graphene oxide: The impact of functional groups

2020 ◽  
Vol 525 ◽  
pp. 146554 ◽  
Author(s):  
Mahdi Tavakol ◽  
Abbas Montazeri ◽  
S. Hamed Aboutalebi ◽  
Reza Asgari
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Functional Groups ◽  
The Impact

Mechanical Properties of Graphene Oxide/Polyvinyl Alcohol Composite Film

2017 ◽  
Vol 25 (1) ◽  
pp. 11-16 ◽  
Author(s):  
Tao Cheng-an ◽  
Zhang Hao ◽  
Wang Fang ◽  
Zhu Hui ◽  
Zou Xiaorong ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Graphene Oxide ◽  
Hydrogen Bonds ◽  
Polyvinyl Alcohol ◽  
Composite Film ◽  
Functional Groups ◽  
Failure Strain ◽  
Oh Groups ◽  
Enhancement Mechanism

Graphene oxide (GO) was served as mechanical strengthening to prepare GO/Polyvinyl Alcohol(PVA) composite film. This was accomplished in order to explore the influence of contents of GO on the tensile strength and failure strain of GO/PVA composite film. The results showed that as the GO content increased, the tensile strength of the composite film became greater rapidly at first, and then decreased gradually. When the GO content was 20%, the film had its maximum tensile strength (59.6 MPa). This is over 500% of the tensile strength of pure PVA film. The failure strain of GO/PVA composite film decreased rapidly as the GO content increased. The enhancement mechanism of the composite can be explained by the existence of multi-hydrogen bonds between the hydroxyl (-OH) groups of PVA and oxygen-containing functional groups of GO.

Synthesis and Characterization of Partially Reduced Graphene Oxide and Platinum and Gold Partially Reduced Graphene Oxide

MRS Advances ◽  
2016 ◽  
Vol 1 (19) ◽  
pp. 1345-1351 ◽  
Author(s):  
Rebecca Isseroff ◽  
Lee Blackburn ◽  
Arthur Chen ◽  
Molly Gentleman ◽  
Miriam Rafailovich
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Functional Groups ◽  
Platinum Nanoparticles ◽  
Synthesis And Characterization ◽  
Reduced Graphene ◽  
Partially Reduced Graphene Oxide

ABSTRACTWhile graphene has unique electrical and mechanical properties, it is not soluble in most common solvents. Partially reducing graphene oxide (prGO) will remove some of the functional groups while still maintaining solubility, producing an intermediate between graphene oxide and reduced graphene oxide. This research investigated the properties of prGO as well as those of prGO sheets incorporated with gold and platinum nanoparticles (Au/Pt-prGO) using FTIR, Raman, TEM and HRTEM.

A Study on the Compressive Performance of C/SiC Lattice Sandwich Panel at High Temperature

2017 ◽  
Vol 09 (08) ◽  
pp. 1750120 ◽  
Author(s):  
Yanfei Chen ◽  
Shigang Ai ◽  
Rujie He ◽  
Kai Wei ◽  
Daining Fang
Keyword(s):  
Mechanical Properties ◽  
Sandwich Panel ◽  
Sandwich Panels ◽  
Simulation Method ◽  
Matrix Cracking ◽  
Tensile Fracture ◽  
Textile Composite ◽  
Out Of Plane ◽  
Compressive Performance ◽  
Abaqus Code

In this study, the mechanical properties and failure behaviors of a C/SiC lattice sandwich panel were investigated by numerical simulation approach. On the bases of Hashin’s criteria, a novel failure criterion for 2D C/SiC textile composite was proposed. An UMAT subroutine based on Abaqus code was constructed to demonstrate the fracture mechanism of the C/SiC composite, in which fiber fracture and buckling, matrix failure and the laminate delamination were considered. Out-of-plane compressive experiments of the C/SiC lattice sandwich panels at room temperature were performed to give verifications of the numerical programmer. Based on the simulation method proposed, the mechanical properties and failure features of the C/SiC lattice sandwich panels at high temperatures were studied. It was found that the junction between struts and the panels of the core firstly damaged due to fiber rupture and matrix cracking. Then fiber tensile fracture and matrix cracking occurred in struts sequentially. Finally, delamination took place at junctions and struts and it trigged the collapse of the sandwich structure.

Lattice Imaging of Grain Boundaries in Ceramics

1977 ◽  
Vol 35 ◽  
pp. 114-115
Author(s):  
D. R. Clarke ◽  
G. Thomas
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Grain Boundaries ◽  
High Temperature Strength ◽  
Current Interest ◽  
Lattice Imaging ◽  
Special Significance ◽  
Structural Applications ◽  
Refractory Ceramics

Grain boundaries have long held a special significance to ceramicists. In part, this has been because it has been impossible until now to actually observe the boundaries themselves. Just as important, however, is the fact that the grain boundaries and their environs have a determing influence on both the mechanisms by which powder compaction occurs during fabrication, and on the overall mechanical properties of the material. One area where the grain boundary plays a particularly important role is in the high temperature strength of hot-pressed ceramics. This is a subject of current interest as extensive efforts are being made to develop ceramics, such as silicon nitride alloys, for high temperature structural applications. In this presentation we describe how the techniques of lattice fringe imaging have made it possible to study the grain boundaries in a number of refractory ceramics, and illustrate some of the findings.

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