scholarly journals Influence of Process Parameters in Graphene Oxide Obtention on the Properties of Mechanically Strong Alginate Nanocomposites

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1081 ◽  
Author(s):  
Izaskun Larraza ◽  
Lorena Ugarte ◽  
Aintzane Fayanas ◽  
Nagore Gabilondo ◽  
Aitor Arbelaiz ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Sodium Alginate ◽  
Graphene Sheets ◽  
Influence Of Process Parameters ◽  
Size Dependent ◽  
Hummers Method ◽  
Exfoliated Graphene ◽  
Enhanced Properties ◽  
Modified Hummers Method

Sodium alginate, a biopolymer extracted from brown algae, has shown great potential for many applications, mainly due to its remarkable biocompatibility and biodegradability. To broaden its fields of applications and improve material characteristics, the use of nanoreinforcements to prepare nanocomposites with enhanced properties, such as carbonaceous structures which could improve thermal and mechanical behavior and confer new functionalities, is being studied. In this work, graphene oxide was obtained from graphite by using modified Hummers’ method and exfoliation was assisted by sonication and centrifugation, and it was later used to prepare sodium alginate/graphene oxide nanocomposites. The effect that different variables, during preparation of graphene oxide, have on the final properties has been studied. Longer oxidation times showed higher degrees of oxidation and thus larger amount of oxygen-containing groups in the structure, whereas longer sonication times and higher centrifugation rates showed more exfoliated graphene sheets with lower sizes. The addition of graphene oxide to a biopolymeric matrix was also studied, considering the effect of processing and content of reinforcement on the material. Materials with reinforcement size-dependent properties were observed, showing nanocomposites with large flake sizes, better thermal stability, and more enhanced mechanical properties, reaching an improvement of 65.3% and 83.3% for tensile strength and Young’s modulus, respectively, for a composite containing 8 wt % of graphene oxide.

Synthesis of Graphene Oxide Nanosheets via Modified Hummers’ Method and Its Physicochemical Properties

2015 ◽  
Vol 74 (1) ◽  
Author(s):  
Mohamad Fahrul Radzi Hanifah ◽  
Juhana Jaafar ◽  
Madzlan Aziz ◽  
Ahmad Fauzi Ismail ◽  
Mukhlis A. Rahman ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Physicochemical Properties ◽  
Functional Groups ◽  
Interlayer Spacing ◽  
Graphene Oxide Nanosheets ◽  
Hummers Method ◽  
Exfoliated Graphene ◽  
Transmission Electron ◽  
Direct Methanol ◽  
Modified Hummers Method

The efficient synthesis of exfoliated graphene oxide nanosheets (GO) via modified Hummers’ method was successfully carried out. The physicochemical properties of GO were determined by Fourier transform infrared spectroscopy (FTIR), UV-visible spectrophotometry (UV-vis), x-ray diffraction analysis (XRD), Raman spectroscopy, and transmission electron microscopy (TEM). The graphite was fully oxidized by strong oxidizing agent caused the oxygen-containing functional groups such as C-O-C, C=O, and COOH were introduced into the graphite layers as analyzed by Raman and FTIR.  XRD pattern of GO showed 2θ of 12.0o with interlayer spacing ~ 7.37A which describe non uniform crystal structure with the addition of oxygen containing functional groups. UV-vis spectrum of GO exhibit maximum absorption peak at ~ 234 nm corresponding to the aromatic C=C bond with π-π* transition. The morphology of GO was observed to have flake-like shape and less transparent layers by TEM. The properties of synthesized GO suggest high potential in producing the high quality of graphene which is can be applied as the electrocatalyst support for direct methanol fuel cell application.              

An experimental investigation on low-cycle fatigue behavior of GO-NH2-reinforced epoxy adhesive

2020 ◽  
pp. 146442072097754
Author(s):  
Jamal Dabbagh ◽  
Bashir Behjat ◽  
Mojtaba Yazdani ◽  
Lucas FM da Silva
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Epoxy Adhesive ◽  
Cycle Fatigue ◽  
Hummers Method ◽  
Optimum Weight ◽  
Modified Hummers Method

In this study, the effect of adding functionalized aminated graphene oxide up to 0.3 wt% was experimentally investigated on the mechanical properties and fatigue behavior of an epoxy adhesive with intermediate toughness. Accordingly, graphene oxide was prepared by a modified Hummers method and was modified with 3-aminopropyltrimethoxysilane silane agent. Bulk samples were then prepared from neat and reinforced adhesive with different weight amounts of aminated graphene oxide. Dumbbell-shaped samples with a notch were used to limit displacement at break. The results showed the presence of 0.1 wt% and 0.3 wt% aminated graphene oxide nanoplatelets, as optimum weight percentages respectively for the mechanical properties and the fatigue life, improves the modulus of elasticity by 35% and the tensile strength by 44% as well as the fatigue life by about 72–241% under different cyclic loading conditions.

Graphene Oxide as a Substrate for Biosensors: Synthesis and Characterization

2021 ◽  
Vol 324 ◽  
pp. 87-93
Author(s):  
Mohamed Adel ◽  
Abdel Hady A. Abdel-Wahab ◽  
Ahmed Abdel-Mawgood ◽  
Ahmed Osman Egiza
Keyword(s):  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
Acidic Solution ◽  
Cost Effective ◽  
Sem Analysis ◽  
Visible Spectroscopy ◽  
Sem Images ◽  
Hummers Method ◽  
Uv Visible ◽  
Modified Hummers Method

Graphene oxide (GO) is an oxidized nanosheets of graphite with a 2D planar structure. GO could be readily complexed with bio-entities as it possesses many oxygen-containing functionalities on its surface. The preparation process is fast, easy, and cost-effective. It was prepared using modified Hummers’ method in acidic solution as a primary solvent and potassium permanganate as an oxidizing agent. Afterwards, it was successfully characterized by FTIR, UV-visible spectroscopy, as well as XRD and Raman spectroscopy, and finally, SEM analysis. It was observed that the formed GO is mainly composed of carbon and oxygen elements rich in oxygen functional groups. Furthermore, the existence of (001) plane in XRD interprets the complete oxidation of graphite with d-spacing 9 Å. Moreover, Raman spectroscopy displayed the sp3 carbon hybridization, besides, the ID/IG ratio is found to be 0.84, which confirms the disorder between graphene oxide layers. The SEM images also pointed out that graphene oxide sheets were regularly stacked together as flake-like structures. Accordingly, the richness of oxygen-containing functionalities was confirmed. Hence, it is appropriate to be used as a base transducer for biosensing applications.

The Synthesis and Characterization of the Graphene Oxide Covalent Modified Phenolic Resin Nanocomposites

2011 ◽  
Vol 327 ◽  
pp. 115-119 ◽  
Author(s):  
Duo Wang ◽  
Jie Gao ◽  
Wei Fang Xu ◽  
Feng Bao ◽  
Rui Ma ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Phenolic Resin ◽  
Synthesis And Characterization ◽  
Infrared Spectrometry ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Hummers Method ◽  
Modified Hummers Method ◽  
Thermal Stability Of

Graphene oxide (GO) was made by a modified Hummers method. Graphene oxide modified phenolic resin nanocomposites (GO/PF) were prepared by Steglich esterification, catalyzed by dicyclohexyl carbodiimide and 4-dimethylaminopyridine. The composites were characterized by Fourier transform infrared spectrometry, differential scanning calorimetry, X-ray powder diffraction, and scanning electron microscopy. The result revealed that the graphene oxide was absolutely exfoliated and covalent linked GO/PF composite was obtained. The thermal stability of PF is remarkably improved by modification with GO.

Mechanical and thermal properties of graphene oxide/ultrahigh molecular weight polyethylene nanocomposites

RSC Advances ◽  
2015 ◽  
Vol 5 (77) ◽  
pp. 63063-63072 ◽  
Author(s):  
Wenchao Pang ◽  
Zifeng Ni ◽  
Guomei Chen ◽  
Guodong Huang ◽  
Huadong Huang ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Graphene Oxide ◽  
Thermal Properties ◽  
Ultrahigh Molecular Weight Polyethylene ◽  
Mechanical And Thermal Properties ◽  
Hummers Method ◽  
Ultrahigh Molecular Weight ◽  
Uhmwpe Composites ◽  
Modified Hummers Method

Graphene oxide (GO) was prepared according to a modified Hummers method, and a range of GO/ultrahigh molecular weight polyethylene (UHMWPE) composites were fabricated then their mechanical and thermal properties were investigated.

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