Nacre-Mimetic Graphene Oxide/Cross-Linking Agent Composite Films with Superior Mechanical Properties

ACS Nano ◽  
2019 ◽  
Vol 13 (4) ◽  
pp. 4522-4529 ◽  
Author(s):  
Ju Yeon Woo ◽  
Jun Ho Oh ◽  
Sunghwan Jo ◽  
Chang-Soo Han
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Composite Films ◽  
Cross Linking ◽  
Superior Mechanical Properties

scholarly journals Hyperbranched polyamide modified graphene oxide-reinforced polyurethane nanocomposites with enhanced mechanical properties

RSC Advances ◽  
2021 ◽  
Vol 11 (24) ◽  
pp. 14484-14494
Author(s):  
Yahao Liu ◽  
Jian Zheng ◽  
Xiao Zhang ◽  
Yongqiang Du ◽  
Guibo Yu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
High Performance ◽  
Cross Linking ◽  
Elongation At Break ◽  
Modified Graphene Oxide ◽  
High Performance Composite ◽  
Modified Graphene ◽  
Polyurethane Nanocomposites ◽  
Hyperbranched Polyamide

We successfully modified graphene oxide with amino-terminated hyperbranched polyamide (HGO), and obtained a high-performance composite with enhanced strength and elongation at break via cross-linking hydroxyl-terminated polybutadiene chains with HGO.

scholarly journals Enhanced antibacterial activity through the controlled alignment of graphene oxide nanosheets

2017 ◽  
Vol 114 (46) ◽  
pp. E9793-E9801 ◽  
Author(s):  
Xinglin Lu ◽  
Xunda Feng ◽  
Jay R. Werber ◽  
Chiheng Chu ◽  
Ines Zucker ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Antibacterial Activity ◽  
Graphene Oxide ◽  
Direct Electron Transfer ◽  
Composite Films ◽  
Experimental Studies ◽  
Cross Linking ◽  
Vertical Orientation ◽  
Electron Transfer Mechanism ◽  
Vertically Aligned

The cytotoxicity of 2D graphene-based nanomaterials (GBNs) is highly important for engineered applications and environmental health. However, the isotropic orientation of GBNs, most notably graphene oxide (GO), in previous experimental studies obscured the interpretation of cytotoxic contributions of nanosheet edges. Here, we investigate the orientation-dependent interaction of GBNs with bacteria using GO composite films. To produce the films, GO nanosheets are aligned in a magnetic field, immobilized by cross-linking of the surrounding matrix, and exposed on the surface through oxidative etching. Characterization by small-angle X-ray scattering and atomic force microscopy confirms that GO nanosheets align progressively well with increasing magnetic field strength and that the alignment is effectively preserved by cross-linking. When contacted with the model bacteriumEscherichia coli, GO nanosheets with vertical orientation exhibit enhanced antibacterial activity compared with random and horizontal orientations. Further characterization is performed to explain the enhanced antibacterial activity of the film with vertically aligned GO. Using phospholipid vesicles as a model system, we observe that GO nanosheets induce physical disruption of the lipid bilayer. Additionally, we find substantial GO-induced oxidation of glutathione, a model intracellular antioxidant, paired with limited generation of reactive oxygen species, suggesting that oxidation occurs through a direct electron-transfer mechanism. These physical and chemical mechanisms both require nanosheet penetration of the cell membrane, suggesting that the enhanced antibacterial activity of the film with vertically aligned GO stems from an increased density of edges with a preferential orientation for membrane disruption. The importance of nanosheet penetration for cytotoxicity has direct implications for the design of engineering surfaces using GBNs.

Moisture Effect on Mechanical Properties of Graphene/Epoxy Nanocomposites

2016 ◽  
Vol 32 (6) ◽  
pp. 673-682 ◽  
Author(s):  
H.-K. Liu ◽  
Y.-C. Wang ◽  
T.-H. Huang
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Moisture Absorption ◽  
Graphene Nanosheets ◽  
Salt Water ◽  
Testing Machine ◽  
Weight Fraction ◽  
Epoxy Nanocomposites ◽  
Moisture Effect ◽  
Superior Mechanical Properties

Abstract2-D graphene nanosheets (GNS) not only have superior mechanical properties, but stacking of GNS in composites is expected to inhibit moisture absorption. In this paper, moisture effect on tensile strength of graphene/epoxy nanocomposites is investigated. Two kinds of graphene reinforcements are used including graphene oxide (GO) and reduced graphene oxide (RGO) with reinforcement weight fraction WGO or WRGO in the range of 0.5 to 3.0wt%. A dispersion agent acetone is added in nanocomposites to enhance graphene dispersion. To evaluate moisture influence, those nanocomposites are soaked in two kinds of liquid including deionized water (DIW) and salt water (saline solution) for seven kinds of soaking periods of time including 24, 48, 72, 100, 400 hours, 30 days, and 60 days. After soaking test, diffusion coefficients of various composites are evaluated; besides tensile strengths of composites are measured by microforce testing machine. In order to correlate the strength with microstructure evolution, several techniques are adopted to analyze morphologies and functionalities of reinforcements and fracture surface of composites. They include Raman spectroscope, X-ray photoelectron spectroscope, and SEM. 2-D GNS are found to effectively enhance nanocomposites by moisture attack, and their corresponding reinforcing mechanisms are proposed.

scholarly journals Synergistic effect of CB and GO/CNT hybrid fillers on the mechanical properties and fatigue behavior of NR composites

RSC Advances ◽  
2018 ◽  
Vol 8 (19) ◽  
pp. 10573-10581 ◽  
Author(s):  
Laiyun Wei ◽  
Xuan Fu ◽  
Mingchao Luo ◽  
Zhengtian Xie ◽  
Cheng Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Carbon Nanotube ◽  
Carbon Black ◽  
Synergistic Effect ◽  
Fatigue Behavior ◽  
Crack Growth Resistance ◽  
Hybrid Fillers ◽  
Superior Mechanical Properties ◽  
Heat Build Up

Graphene oxide (GO) and carbon nanotube (CNT) hybrid fillers were used to replace partial carbon black (CB), and GO/CNT/CB/NR composites were prepared with excellent crack growth resistance, low heat build-up and superior mechanical properties.

Hydroxyapatite Bioceramics Reinforced with Silica-Coated Graphene

2017 ◽  
Vol 758 ◽  
pp. 150-154 ◽  
Author(s):  
Zhong Li ◽  
Shu Guang Bi ◽  
Rui Tao Li ◽  
Khiam Aik Khor
Keyword(s):  
Mechanical Properties ◽  
Adverse Effect ◽  
Fracture Toughness ◽  
Graphene Oxide ◽  
Orthopedic Implants ◽  
Human Osteoblast ◽  
Reinforced Composites ◽  
Plasma Sintering ◽  
Proliferation And Differentiation ◽  
Superior Mechanical Properties

Challenges facing graphene-reinforced composites include insufficient interfacial strengths, filler agglomeration, and their potential cytotoxicity. To tackle these challenges, silica-coated graphene (S-G) is used to toughen a representative bioceramic, hydroxyapatite (HA), and HA-based composites were prepared by park plasma sintering. By adding 2 wt.% silica-coated graphene oxide, a precursor to S-G, the fracture toughness of HA could be increased by 84%. Compared with graphene/HA pellets, the S-G/HA samples showed superior mechanical properties. In addition, the incorporation of S-G could promote the proliferation and differentiation of human osteoblast-like cells MG63, and showed no adverse effect on their viability. Therefore, the multifunctional bioceramic-based materials presented here possess great potential in load-bearing orthopedic implants.

Robust ultraviolet shielding and enhanced mechanical properties of graphene oxide/sodium alginate composite films

2015 ◽  
Vol 50 (17) ◽  
pp. 2365-2374 ◽  
Author(s):  
Xili Hu ◽  
Xiansheng Zhang ◽  
Mingwei Tian ◽  
Lijun Qu ◽  
Shifeng Zhu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Sodium Alginate ◽  
Composite Films ◽  
Ultraviolet Shielding
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