Articles de revues : « Oxyde de graphène »

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Inagaki, Michio, et Feiyu Kang. « Graphene derivatives : graphane, fluorographene, graphene oxide, graphyne and graphdiyne ». J. Mater. Chem. A 2, n^o 33 (2014) : 13193–206. http://dx.doi.org/10.1039/c4ta01183j.

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Cao, Qiang, Xiao Geng, Huaipeng Wang, Pengjie Wang, Aaron Liu, Yucheng Lan et Qing Peng. « A Review of Current Development of Graphene Mechanics ». Crystals 8, n^o 9 (6 septembre 2018) : 357. http://dx.doi.org/10.3390/cryst8090357.

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Graphene, a two-dimensional carbon in honeycomb crystal with single-atom thickness, possesses extraordinary properties and fascinating applications. Graphene mechanics is very important, as it relates to the integrity and various nanomechanical behaviors including flexing, moving, rotating, vibrating, and even twisting of graphene. The relationship between the strain and stress plays an essential role in graphene mechanics. Strain can dramatically influence the electronic and optical properties, and could be utilized to engineering those properties. Furthermore, graphene with specific kinds of defects exhibit mechanical enhancements and thus the electronic enhancements. In this short review, we focus on the current development of graphene mechanics, including tension and compression, fracture, shearing, bending, friction, and dynamics properties of graphene from both experiments and numerical simulations. We also touch graphene derivatives, including graphane, graphone, graphyne, fluorographene, and graphene oxide, which carve some fancy mechanical properties out from graphene. Our review summarizes the current achievements of graphene mechanics, and then shows the future prospects.

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Strankowski, Michał, Damian Włodarczyk, Łukasz Piszczyk et Justyna Strankowska. « Polyurethane Nanocomposites Containing Reduced Graphene Oxide, FTIR, Raman, and XRD Studies ». Journal of Spectroscopy 2016 (2016) : 1–6. http://dx.doi.org/10.1155/2016/7520741.

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Recently, graphene and other graphene-based materials have become an essential part of composite science and technology. Their unique properties are not only restricted to graphene but also shared with derivative compounds like graphene oxide, reduced graphene oxide, functionalized graphene, and so forth. One of the most structurally important materials, graphene oxide (GO), is prepared by the oxidation of graphite. Though removal of the oxide groups can create vacancies and structural defects, reduced graphene oxide (rGO) is used in composites as effective filler similar to GO. Authors developed a new polyurethane nanocomposite using a derivative of grapheme, thermally reduced graphene oxide (rGO), to modify the matrix of polyurethane elastomers, by rGO.

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Banerjee, Arghya Narayan. « Graphene and its derivatives as biomedical materials : future prospects and challenges ». Interface Focus 8, n^o 3 (20 avril 2018) : 20170056. http://dx.doi.org/10.1098/rsfs.2017.0056.

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Graphene and its derivatives possess some intriguing properties, which generates tremendous interests in various fields, including biomedicine. The biomedical applications of graphene-based nanomaterials have attracted great interests over the last decade, and several groups have started working on this field around the globe. Because of the excellent biocompatibility, solubility and selectivity, graphene and its derivatives have shown great potential as biosensing and bio-imaging materials. Also, due to some unique physico-chemical properties of graphene and its derivatives, such as large surface area, high purity, good bio-functionalizability, easy solubility, high drug loading capacity, capability of easy cell membrane penetration, etc., graphene-based nanomaterials become promising candidates for bio-delivery carriers. Besides, graphene and its derivatives have also shown interesting applications in the fields of cell-culture, cell-growth and tissue engineering. In this article, a comprehensive review on the applications of graphene and its derivatives as biomedical materials has been presented. The unique properties of graphene and its derivatives (such as graphene oxide, reduced graphene oxide, graphane, graphone, graphyne, graphdiyne, fluorographene and their doped versions) have been discussed, followed by discussions on the recent efforts on the applications of graphene and its derivatives in biosensing, bio-imaging, drug delivery and therapy, cell culture, tissue engineering and cell growth. Also, the challenges involved in the use of graphene and its derivatives as biomedical materials are discussed briefly, followed by the future perspectives of the use of graphene-based nanomaterials in bio-applications. The review will provide an outlook to the applications of graphene and its derivatives, and may open up new horizons to inspire broader interests across various disciplines.

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Xiao, Zhen Hui, Shui Sheng Wu, Yan Lin Sun, Yu Lin Zhao et Ya Ming Wang. « Microwave-Hydrothermal Synthesis and Characterization of Graphene ». Advanced Materials Research 602-604 (décembre 2012) : 917–20. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.917.

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Graphene was synthesized by microwave-hydrothermal chemical reduction of graphite oxide using hydrazine hydrate as the reducing agent. Graphene was characterized using X-ray diffraction, UV-visible spectrum, FT-IR spectrum and scanning electron microscopy. Results indicated that the as-prepared graphene was wrinkled and comprised fewer graphenes with a highly crystalline structure.

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J, Monica, et Divyasankari G. « Experimental Study on Green Concrete using Graphene ». International Journal of Innovative Research in Advanced Engineering 10, n^o 07 (31 juillet 2023) : 486–89. http://dx.doi.org/10.26562/ijirae.2023.v1007.07.

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The paper considers methods for concrete modification using low-layer graphene and grapheme oxide. It was found that graphene oxide and low-layer graphene obtained by liquid-phase shear exfoliation significantly increase the strength of concrete. In our opinion, low-layer graphene has better prospects since it is cheaper and its production technology is environmentally friendly. The viability and future of graphene largely depends on the availability of such a method that allows mass production of high-quality graphene at an affordable price. In this regard, liquid- phase separation of graphite with the formation of low-layer graphene, which can be used to modify concrete, turned out to be a competitive solution. The following main tasks were formulated in order to solve the organizational problems of low- layer grapheme industrial production: reducing the concentration of low-layer grapheme in concrete; increasing the concentration of low-layer graphene in suspension; developing an industrial technology for the production of concentrate with a high content of low- layer graphene; conducting full-scale experimental studies to determine the optimal concentration of low-layer graphene in concrete.

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Wang, Xuan Lun, et Wei Jiu Huang. « Fabrication and Characterization of Graphene/Polyimide Nanocomposites ». Advanced Materials Research 785-786 (septembre 2013) : 138–44. http://dx.doi.org/10.4028/www.scientific.net/amr.785-786.138.

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Graphene/polyimide nanocomposites with different weight loadings were prepared by a solution compounding technique. Graphene was synthesized from graphite oxide that was fabricated by the Hummers method. X-ray diffraction (XRD), ultraviolet visible (UV-vis) spectra and simultaneous thermal analysis were used for the microstructure analysis of the graphenes. Graphenes with single layer structure were synthesized successfully and had good solubility in water or other polar solvents due to a few functional groups on the graphene carbons. Graphenes have good thermal stability. Mechanical and tribological properties were studied for the graphene/polyimide composites. The composites have excellent strength and toughness with very small graphene loading level and the addition of graphene decreased the friction coefficient and wear rate of the composites.

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Li, Jinghao, Qiangu Yan, Xuefeng Zhang, Jilei Zhang et Zhiyong Cai. « Efficient Conversion of Lignin Waste to High Value Bio-Graphene Oxide Nanomaterials ». Polymers 11, n^o 4 (4 avril 2019) : 623. http://dx.doi.org/10.3390/polym11040623.

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Lignin graphene oxide was oxidized after Kraft lignin was graphitized by thermal catalytic conversion. The reduced lignin graphene oxide was derived from lignin graphene oxide through thermal reduction treatment. These Kraft lignin, lignin graphite, lignin graphene oxide, and reduced lignin graphene oxide were characterized by scanning electron microscopy, raman microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, atomic force microscopy and thermogravimetric analysis. The results showed lignin graphite converted from Kraft lignin had fewer layers with smaller lateral size than natural graphite. Moreover, lignin graphene oxide was successfully produced from lignin graphite by an oxidation reaction with an hour-long reaction time, which has remarkably shorter reaction time than that of graphene oxide made from natural graphite. Meanwhile, this lignin-derived graphene oxide had the same XRD, FTIR and Raman peaks as graphene oxide oxidized from natural graphite. The SEM, TEM, and AFM images showed that this lignin graphene oxide with 1–3 average layers has a smaller lateral size than that of graphene oxide made from natural graphite. Moreover, the lignin graphene oxide can be reduced to reduced lignin graphene oxide to fabricate graphene-based aerogel, wire, and film for some potential applications.

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Wang, Yachao, et Jiangping Zhao. « Effect of Graphene on Flame Retardancy of Graphite Doped Intumescent Flame Retardant (IFR) Coatings : Synergy or Antagonism ». Coatings 9, n^o 2 (3 février 2019) : 94. http://dx.doi.org/10.3390/coatings9020094.

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A comparative study between graphene and modified graphene oxide (mGO) on the flame retardancy of graphite doped intumescent flame retardant (IFR) coatings is preliminarily investigated by cone calorimeter (CC), XRD, and SEM, with the final aim of clarifying the interactions between different graphenes and graphite doped coatings (polyester resin-ammonium polyphosphate-urea-pentaerythritol). The CC results determine that graphene exerts an obviously antagonistic effect on flame resistance, evidenced by the increased peak heat release rate (p-HRR) of 56.9 kW·m−2 for SD8+graphene (sample coating contains graphite with a particle size of 8 μm and 0.5 wt.% graphene as dopant), which increased by 80.6% compared with SD8 (coating contains graphite with a particle size of 8 μm); substitution with graphene or mGO imparts an acceleration of fire growth, because graphene inertness improves the viscosity of melting system, evidenced by the cracked appearance and porous structure of SD8+graphene. However, the higher reactivity of mGO favors the combustion; the barrier effect inhibits the transfer of mass and heat simultaneously, leading to a slight influence on flame retarding efficiency.

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Abaszade, R. G. « Synthesis and analysis of flakes graphene oxide ». Journal of Optoelectronic and Biomedical Materials 14, n^o 3 (juillet 2022) : 107–14. http://dx.doi.org/10.15251/jobm.2022.143.107.

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The presented article is devoted to the synthesis and analysis of flakes graphene oxide obtained by the Hammers method. The synthesized flakes graphene oxide was studied using SEM, EDX, X-ray diffraction, Raman spectroscopy, element analysis, temperature dependent of resistance and IR spectroscopy. As a result of calculating the results of X-ray analysis according to the Debye-Scherer’s formula, the thickness of graphite flakes was about 12,9nm and the number of layers was 38. The result of the Raman analysis show that high quality flakes grapheme oxide was obtained. Based on the result of elementary analysis of grapheme oxide mass, the C/O ratio was determined to be 1,42. The grapheme layers inside the sample were 3,31nm thick and 14,8nm long by scanning electron microscope. The temperature variation of the resistance was determined. IR spectroscopy shows the results of the absorption of electromagnetic radiation in the infrared range by atomic groups of reduced grapheme oxide and the excitation of the molecule by light quanta. When a molecule is irradiated with infrared radiation, it is shown that only quantum absorption quantities are formed according to the frequencies of the molecules.

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Cao, Ning, et Yuan Zhang. « Study of Reduced Graphene Oxide Preparation by Hummers’ Method and Related Characterization ». Journal of Nanomaterials 2015 (2015) : 1–5. http://dx.doi.org/10.1155/2015/168125.

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As a novel two-dimensional carbon material, graphene has fine potential applications in the fields of electron transfer agent and supercapacitor material for its excellent electronic and optical property. However, the challenge is to synthesize graphene in a bulk quantity. In this paper, graphite oxide was prepared from natural flake graphite by Hummers’ method through liquid oxidization, and the reduced graphene oxide was obtained by chemical reduction of graphene oxide using NH3·H2O aqueous solution and hydrazine hydrate. The raw material graphite, graphite oxide, and reduced graphene oxide were characterized by X-ray diffraction (XRD), attenuated total reflectance-infrared spectroscopy (ATR-IR), and field emission scanning electron microscope (SEM). The results indicated that the distance spacing of graphite oxide was longer than that of graphite and the crystal structure of graphite was changed. The flake graphite was oxidized to graphite oxide and lots of oxygen-containing groups were found in the graphite oxide. In the morphologies of samples, fold structure was found on both the surface and the edge of reduced graphene oxide.

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RAO, C. N. R., K. S. SUBRAHMANYAM, H. S. S. RAMAKRISHNA MATTE et A. GOVINDARAJ. « GRAPHENE : SYNTHESIS, FUNCTIONALIZATION AND PROPERTIES ». Modern Physics Letters B 25, n^o 07 (20 mars 2011) : 427–51. http://dx.doi.org/10.1142/s0217984911025961.

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Graphenes with varying number of layers can be synthesized by different strategies. Thus, single-layer graphene is obtained by the reduction of single layer graphene oxide, CVD and other methods besides micromechanical cleavage. Few-layer graphenes are prepared by the conversion of nanodiamond, arc-discharge of graphite and other means. We briefly present the various methods of synthesis and the nature of graphenes obtained. We then discuss the various properties of graphenes. The remarkable property of graphene of quenching fluorescence of aromatic molecules is shown to be associated with photo-induced electron transfer, on the basis of fluorescence decay and time-resolved transient absorption spectroscopic measurements. The interaction of electron donor and acceptor molecules with few-layer graphene samples has been discussed. Decoration of metal nano-particles on graphene sheets and the resulting changes in electronic structure are examined. Few-layer graphenes exhibit ferromagnetic features along with antiferromagnetic properties, independent of the method of preparation. Graphene-like MoS 2 and WS 2 have been prepared by chemical methods, and the materials are characterized by electron microscopy, atomic force microscopy (AFM) and other methods. Boron nitride analogues of graphene have been obtained by a simple chemical procedure starting with boric acid and urea and have been characterized by various techniques.

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RAO, C. N. R., K. S. SUBRAHMANYAM, H. S. S. RAMAKRISHNA MATTE, URMIMALA MAITRA, KOTA MOSES et A. GOVINDARAJ. « GRAPHENE : SYNTHESIS, FUNCTIONALIZATION AND PROPERTIES ». International Journal of Modern Physics B 25, n^o 30 (10 décembre 2011) : 4107–43. http://dx.doi.org/10.1142/s0217979211059358.

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Graphenes with varying number of layers can be synthesized by different strategies. Thus, single-layer graphene is obtained by the reduction of single layer graphene oxide, CVD and other methods besides micromechanical cleavage. Few-layer graphenes are prepared by the conversion of nanodiamond, arcdischarge of graphite and other means. We briefly present the various methods of synthesis and the nature of graphenes obtained. We then discuss the various properties of graphenes. The remarkable property of graphene of quenching fluorescence of aromatic molecules is shown to be associated with photo-induced electron transfer, on the basis of fluorescence decay and time-resolved transient absorption spectroscopic measurements. The interaction of electron donor and acceptor molecules with few-layer graphene samples has been discussed. Decoration of metal nano-particles on graphene sheets and the resulting changes in electronic structure are examined. Few-layer graphenes exhibit ferromagnetic features along with antiferromagnetic properties, independent of the method of preparation. Graphene-like MoS 2 and WS 2 have been prepared by chemical methods, and the materials are characterized by electron microscopy, atomic force microscopy (AFM) and other methods. Boron nitride analogues of graphene have been obtained by a simple chemical procedure starting with boric acid and urea and have been characterized by various techniques.

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N. Bonnia, N., A. Z. Zanuri, N. A. Asli, N. A. Masdar, S. Ratim, S. M. Yahaya, M. M. Mahat et R. Ramli. « Synthesis of Graphene Oxide from Waste Carbon Tyre using Modified Hummer’s Method ». International Journal of Engineering & ; Technology 7, n^o 4.14 (24 décembre 2019) : 352. http://dx.doi.org/10.14419/ijet.v7i4.14.27673.

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Recently, graphene was produced from graphite powder using chemical vapour deposition (CVD) or Hummer’s method. Graphene is widely used in many applications and give a lot of advantages for industry. In this study, graphene oxide was synthesized from waste carbon tyre using modified Hummer’s method. This green technology turned waste material to wealth. The morphology and structural properties of the graphene oxide were investigated using Raman spectroscopy, scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX). Raman analysis was confirmed that graphene oxide was successfully synthesized from waste carbon tyre. It was confirmed the peaks shows that D band and G band was at 1361 cm-1 and 1596 cm-1 with the intensity ratio of the D band relative to the G band (ID/IG) is 0.88. The formation of few sheets of grapheme oxide that stalked together on the surface of the sample structure, bumping pieces and coarse surface was confirmed by scanning electron microscopy (SEM). The elemental composition of carbon (C) is 50.90 % and oxygen (O) is 49.10% which showed a good composition for graphene oxide. All the results were confirmed that the graphene oxide has been synthesized from waste carbon tyre using modified Hummer’s method which next will forms graphene powder through exfoliation method.

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Mai, Tam Thanh, Nhan Thuc Chi Ha et Huy Thuc Ha. « A new method to exfoliate Graphite oxide and application for synthesis Graphene by chemical method ». Science and Technology Development Journal 17, n^o 2 (30 juin 2014) : 27–34. http://dx.doi.org/10.32508/stdj.v17i2.1312.

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A new method to separate graphite oxide (GO) modified by polyethylene oxide (PEO) by the aid of ultrasonic radiation was developed. Modified GO (graphene oxide or single layer of graphite oxide) did not show not appear crystalline peak (d002) on the X-Ray and took the form of a single layer graphene oxide on the image AFM and TEM. The exfoliated graphene oxide was reduced (RGO) to graphene by the reducing agent system HI – Acetic acid (HI-AcOH). The sheet resistance of RGOHI-AcOH is about 120 Ω/sq in the form graphene paper. In addition, FTIR, UV-Vis and Raman spectra showed more clearly about characteristics of graphite oxide, graphene oxide and RGOHI-AcOH.

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Loryuenyong, Vorrada, Krit Totepvimarn, Passakorn Eimburanapravat, Wanchai Boonchompoo et Achanai Buasri. « Preparation and Characterization of Reduced Graphene Oxide Sheets via Water-Based Exfoliation and Reduction Methods ». Advances in Materials Science and Engineering 2013 (2013) : 1–5. http://dx.doi.org/10.1155/2013/923403.

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This research studied the synthesis of graphene oxide and graphene via a low-cost manufacturing method. The process started with the chemical oxidation of commercial graphite powder into graphite oxide by modified Hummer’s method, followed by the exfoliation of graphite oxide in distilled water using the ultrasound frequency from a laboratory ultrasonic bath. Finally, the oxygen functional groups on exfoliated graphite oxide or graphene oxide were eliminated by stirring in hot distilled water at 95°C, as a replacement for highly toxic and dangerously unstable hydrazine. The results assured that stirring in hot distilled water could give the product of graphene or reduced graphene oxide. The samples were characterized by FTIR, XRD, TGA, Raman spectroscopy, SEM, and TEM methods.

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Lv, Ya Nan, Jian Fang Wang, Yin Long, Cheng An Tao, Lin Xia et Hui Zhu. « How Graphene Layers Depend on Drying Methods of Graphene Oxide ». Advanced Materials Research 554-556 (juillet 2012) : 597–600. http://dx.doi.org/10.4028/www.scientific.net/amr.554-556.597.

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Abstract: Graphite oxide is of great importance in preparing graphene, the average layer of graphene depends on that of graphene oxide in some extent. In this paper, we prepared graphite oxide via H3PO4/H2SO4mixed acid, then which were dried by vacuum drying in a freezer dryer and drying oven respectively, the graphite oxide powder and thin film were obtained correspondingly. After dispersing the above two forms of graphite oxide in water by shaking, stirring or supersonic wave, they were reduced in the same condition. According to the XRD, AFM results, vacuum freeze-drying was inclined to gain few-lay graphene.

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Kamisan, Ainnur Izzati, Lili Widarti Zainuddin, Ainnur Sherene Kamisan, T. I. T. Kudin, Oskar Hasdinor Hassan, Norhana Abdul Halim et Muhd Zu Azhan Yahya. « Ultrasonic Assisted Synthesis of Reduced Graphene Oxide in Glucose Solution ». Key Engineering Materials 708 (septembre 2016) : 25–29. http://dx.doi.org/10.4028/www.scientific.net/kem.708.25.

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A new carbon material viz. graphene has been attracted an increasing research interest owing to its unique electrical and mechanical properties that is useful for the various device applications. The synthesis of graphene from graphene oxide usually involves harmful chemical reducing agents that are toxic and undesirable to human and the environment. By avoiding the use of toxic and environmentally harmful reductants, we report a green approach to effectively reduce graphene oxide to graphene in glucose solution at room temperature. Graphite oxide was synthesized from graphite powder using modified Hummers’ method. Graphite oxide then further exfoliated to graphene oxide by using ultrasonic irradiation. The mild reduction of graphene oxide is carried out by mixing graphene oxide solution with glucose. The reduction time is varied with 15, 30, 45 and 60 minutes. TEM images provide clear evidence for the formation of few layer graphene. Characterization of theresulting glucose reduced graphene oxide by FTIR indicates the partial removal of oxygen-containing functional groups from the surface of graphene oxide and formation of graphene with defects.

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Yu, Hui Jiang, Zheng Guang Zou, Fei Long, Chun Yan Xie et Hao Ma. « Preparation of Graphene with Ultrasound-Assisted in the Process of Oxidation ». Applied Mechanics and Materials 34-35 (octobre 2010) : 1784–87. http://dx.doi.org/10.4028/www.scientific.net/amm.34-35.1784.

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To get single-layer of graphene, exfoliating fully intercalated graphite oxide into single- layer graphene oxide is one of the important factors. In this paper, graphite oxide prepared by the Improved Hummers Method, and ultrasound was added to the Low-temperature Reaction of this oxidation process to improve the efficiency of intercalation. Then the obtained graphene oxide was dispersed with surfactant and reduced with Hydrazine Hydrate. XRD patterns indicated that the layer distance of graphite oxide did increased at the aid of the ultrasound, and the obtained reduced products were single- and few-layer. FT-IR analysis further confirmed the preparation of graphite oxide and graphene.

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Chen, Dong Zhi, et Xue Mei Lin. « Preparation of Graphene by Green Reduction Method and Characterization ». Advanced Materials Research 807-809 (septembre 2013) : 515–20. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.515.

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Graphite oxide was prepared by Hummers method and got graphene oxide by ultrasonic dispersion in water, and using a cheap and environment-friendly fructose as reductant, graphene oxide could be reduced into graphene under mild condition. Meanwhile, the structure and morphology of obtained product was characterized and analyzed by testing methods such as Fourier transform Infrared spectroscopy, X-ray diffraction, Laser Raman spectroscopy, Transmission electron microscope and so on. In addition, the electrical conductivity of obtained graphene was determinated.The experimental results show that graphite oxide can be reduced by fructose under mild conditions and can get graphene with good structure and dispersibility. And the electrical conductivity of graphene prepared by the reduction of graphite oxide with fructose is 35.7 Scm-1, which has great improvement on conducting performance compared with graphite oxide. Moreover, It is non-toxic, non-polluting and friendly to the environment in preparation process of graphene, which lays the groundwork for mass production of graphene materials.

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Guo, Yan Hua, Dong Xian Zhuo, Li Xin Wu, Lin Ma, Zi Xiang Weng et Rui Wang. « A Facile and Efficient Method to Prepare Exfoliated and Reduced Graphene Nanosheets by Detonation ». Advanced Materials Research 937 (mai 2014) : 260–66. http://dx.doi.org/10.4028/www.scientific.net/amr.937.260.

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A facile, efficient, and low energy consumption detonation method to prepare few-layered graphene nanosheets has been developed using graphite oxide as a precursor at detonation induced temperature as low as 100 °C . The composition and structure of as-produced few-layered graphenes were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared (FTIR), Specific Surface (BET), Transmission Electron Microscopy (TEM), Raman Microscope, and Atomic Force Microscope (AFM). Results showed that the as-produced graphenes were transparent and few-layered with a high specific surface area (225.9 m2/g). The investigation opens a new road to prepare few-layered graphene nanosheets at low exfoliation temperature in a low-cost and facile way.

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Minitha, Cherukutty Ramakrishnan, et Ramasamy Thangavelu Rajendrakumar. « Synthesis and Characterization of Reduced Graphene Oxide ». Advanced Materials Research 678 (mars 2013) : 56–60. http://dx.doi.org/10.4028/www.scientific.net/amr.678.56.

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Reduced graphene oxide is an excellent candidate for various electronic devices such as high performance gas sensors. In this work Graphene oxide was prepared by oxidizing graphite to form graphite oxide. From XRD analysis the peak around 11.5o confirmed that the oxygen was intercalated into graphite. By using hydrazine hydrate, the epoxy group in graphite oxide was reduced then the solution of reduced graphite oxide (rGO) is exfoliated. Raman spectrum of rGO contains both G band (1580 cm-1), D band (1350 cm-1). The remarkable structural changes reveals that reduction of graphene oxide from the values of ID/IG ratio that increase from 0.727 (GO) to 1.414 (rGO). The exfoliated reduced graphite oxide solution is spin coated on to the SiO2/Si substrates.

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Kamisan, Ainnur Izzati, Ainnur Sherene Kamisan, Ruslinda Md Ali, Tunku Ishak Tunku Kudin, Oskar Hasdinor Hassan, Norhana Abdul Halim et Mohamad Faizul Yahya. « Synthesis of Graphene via Green Reduction of Graphene Oxide with Simple Sugars ». Advanced Materials Research 1107 (juin 2015) : 542–46. http://dx.doi.org/10.4028/www.scientific.net/amr.1107.542.

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A new carbon material called graphene has been attracting an increasing research interest owing to its unique electrical and mechanical properties that is useful for the various device applications. The synthesis of graphene from graphene oxide usually involves harmful chemical reducing agents that are toxic and undesirable to human and the environment. By avoiding the use of toxic and environmentally harmful reductants, we report a green approach for the reduction of graphene oxide by using reducing sugars to synthesis graphene. Graphite oxide was synthesized from graphite powder using modified Hummers method. Graphite oxide then further exfoliated to graphene oxide by using ultrasonic irradiation. Graphene then was obtained by the mild reduction of graphene oxide with reducing sugars (glucose, lactose and maltose). The structural study of the as-prepared graphene is characterized by Raman spectroscopy and fourier infra red spectroscopy. Raman and FTIR spectra indicates the partial removal of oxygen functional groups from the surface of GO. Characterizations indicate that graphene oxide is successfully reduced to graphene by sugar.

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Li, Pei Pei, et Bao Xiang Deng. « Research on Carbon Materials with Synthesis and Characterization of Graphene-Based ». Advanced Materials Research 1003 (juillet 2014) : 100–104. http://dx.doi.org/10.4028/www.scientific.net/amr.1003.100.

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Carbon materials has been a popular application materials, especially in graphene. Graphene, the mother of all graphitic materials, has emerged to become an exciting two-dimensional material with wondrous properties. Atomic and electronic structures of graphene have been investigated by employing a variety of micro-scopic, spectroscopic, and other techniques. The results show it has better thermal stability, and larger surface area than graphite, graphite oxide. Keywords: graphite; oxidation-reduction method; graphite oxide; graphene

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Lei, Yun, Jun Xu, Rong Li et Fei Fei Chen. « Acidification Assisted Preparation of Graphite Oxide and Graphene ». Advanced Materials Research 988 (juillet 2014) : 36–39. http://dx.doi.org/10.4028/www.scientific.net/amr.988.36.

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Graphite oxide was prepared by acidification assisted Hummers method, which contains acidification, medium temperature and high-temperature three stages. Traditional Hummers low-temperature process was replaced by acidification process. The dosages of acid, graphite and potassium permanganate were investigated, and the produced graphite oxide was treated by ultrasonic oscillation and reduced to graphene by refluxing the reaction mixture at 100°C under open-air conditions. The structure of natural graphite, graphite oxide and graphene were characterized by X-ray diffractometry and infrared spectrum, the morphology of graphene was observed on a scanning electron microscope and the electrochemical properties of graphene were analyzed by the three-electrode cyclic voltammetry test system.

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Taufantri, Yudha, Irdhawati Irdhawati et Ida Ayu Raka Astiti Asih. « Sintesis dan Karakterisasi Grafena dengan Metode Reduksi Grafit Oksida Menggunakan Pereduksi Zn ». Jurnal Kimia VALENSI 2, n^o 1 (31 mai 2016) : 17–23. http://dx.doi.org/10.15408/jkv.v2i1.2233.

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Graphene is a thin material, has a hexagonal two-dimentional lattice and is considered as an interesting material for adsorption process. Nowadays, graphene has been known as a potential material for diverse application, such as adsorbent. In this study graphene was synthesized from graphite. Furthermore, graphene was applied for adsorption of dichloro diphenyl trichloroethane (DDT). Graphene was synthesized by Hummer’s method using hydrothermal and reduced by Zn. The samples were characterized by Scanning Electron Microscope (SEM) and X-Ray Diffraction (XRD) methods. The results of the XRD showed graphene structure in the 2θ, appeared at 23.9369 with interlayer spacing was about 3.71763 Å, compared with graphite oxide structure in the 2θ appeared at 11.2055 with interlayer spacing was about 7.89649 Å. The results of SEM analysis showed graphene has one layer with planar hexagonal structure and seems transparent whose single layer and multi layers. The graphene adsorption was analyzed by using the UV-Visible spectrophotometer. The results indicated the surface area of graphene was shown as 46.8563 m2/g. The amount of DDT adsorbed by graphene during 15 minutes was 7.5859 mg/g. This adsorption mechanism of DDT and graphene might be due to π-π and hydrogen interactions. Keywords: Adsorption, dichloro diphenyl trichloroethane (DDT), graphena. DOI: http://dx.doi.org/10.15408/jkv.v2i1.2233

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Said, Muhammad, Maria Ulfa, Addy Rachmat, Desnelli et Poedji Loekitowati Hariani. « Synthesis of Reduced Graphene Oxide from Cellulose and its Applications for Methylene Blue Adsorption ». Solid State Phenomena 345 (28 juillet 2023) : 153–70. http://dx.doi.org/10.4028/p-n4sufo.

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This paper reports the synthesis and its application to the adsorption of methylene blue dye using graphene-oxide (GO) and reduced graphene-oxide (RGO). Among carbon-based nanomaterials, graphene and its derivatives have received remarkable attention due to their unique thermal, mechanical, and electronic properties and two-dimensional structure. The GO was synthesized by the modified Hummers method (chemical exfoliation) of graphite flake. This reaction produced graphite oxide (GrO) as an intermediate material. The synthesized materials, namely graphite, graphene oxide, and reduced graphene oxide, were characterized by XRD, FTIR, and Raman spectroscopy. These materials were tested to evaluate their adsorption capacity, concentration, contact time, and adsorbent weight on methylene blue, which was analyzed using a UV-vis spectrophotometer. The XRD pattern showed the formation of 2θ peaks at 24° to 26o for graphite, graphene oxide, and reduced graphene oxide, respectively. Furthermore, characterization by FTIR showed the appearance of O-H groups with peaks of 3358 cm-1 and 3342 cm-1 for graphene and reduced graphene oxides. Raman characterization indicated that reduced graphene oxide has a wavelength at the D-band peak of about 1375 cm-1 and the G-band peak reaching 1597 cm-1 with an ID/IG intensity ratio of 0.8. The adsorption test of methylene blue showed that reduced graphene oxide had the best adsorption capacity with an adsorbent, concentration, optimum time, and highest adsorption capacity value of 25 mg, 30 ppm, 45 minutes, and 15.642 mg/g. The adsorption process followed the Langmuir isotherm rule, as evidenced by the R2 value of 0.9881.

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Czajka, Michael, Robert A. Shanks et Ing Kong. « Preparation of graphene and inclusion in composites with poly(styrene-b-butadiene-b-styrene) ». Science and Engineering of Composite Materials 22, n^o 1 (1 janvier 2015) : 7–16. http://dx.doi.org/10.1515/secm-2013-0119.

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AbstractThe aim of this work was to prepare and characterize nanocomposites containing graphene from intercalated graphite. The graphene was produced by rapid thermal expansion using expandable graphite oxide or obtained commercially. The polymer used was poly(styrene-b-butadiene-b-styrene) (SBS). The SBS was dissolved in p-xylene and the graphene was ultrasonically suspended in the xylene solution. The morphology, dynamic mechanical, electrical, and thermal properties of composites were characterized. Graphene at 1% (w/w) (hydrogen atmosphere) was found to increase the storage modulus (68%) and loss modulus (147%) of the glassy state of polybutadiene in SBS. The damping factor of SBS was enhanced by 74% corresponding to the polystyrene phase of SBS using Cheap Tubes graphene. The composites were insulators at 1% (w/w). The styrene groups in SBS strongly adsorb onto the graphenes, preventing a percolation network that would enhance electrical permittivity. Graphene enhanced physical crosslinks of the polystyrene phase to increase the modulus at low concentration. Graphene dispersion using ultrasonic shear depended on π-π interactions between the aromatic rings of the solvent, graphene, and polystyrene. This is a simple, fast, cheap, and scalable way of making high-quality graphene and a new way of graphene dispersal in polymers.

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NAEEM, Nida, Mudassar ABBAS et Mumtaz Hasan MALIK. « GRAPHENE/GRAPHENE OXIDE BASED COATINGS FOR ADVANCED TEXTILE APPLICATIONS ». TEXTEH Proceedings 2019 (5 novembre 2019) : 148–52. http://dx.doi.org/10.35530/tt.2019.31.

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Today, graphene oxide has been significantly used in many technological sectors, medical sectors as well in textiles due to its abundant applications and dominant characteristics. Graphene oxide is basically a mono layered material synthesized by the oxidation of graphite by the addition of multiple functional groups containing oxygen such as alcohols, carboxylic acids and epoxides and presenting a 2-diamentional honeycomb structure. On the textile surfaces the grapheme oxide can be applied through Pad dry-cure, Dip dry-cure and Spray coating methods. However, the most appropriate method is dipping of the fabric into the graphene suspension and the process is followed by drying and curing techniques. Initially, the fabric swatches have been cut out in a suitable size according to the padder or adjustments on the machine can also be done. 100% pure cotton, polyester, cotton polyester blend, silk, aramids and acrylics have been used as a substrate for the application of graphene to imparts different functional properties. The oxygen content is reduced resulting the increase in the interlayer spacing’s well as functionalization. The oxygen containing groups have been removed with the repossession of the conjugated structure. The reduced graphene oxide has the higher strength as well as high electrical and thermal conductivity which effect the final performance of a materials.

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Bastiurea, Marian, Dumitru Dima et Gabriel Andrei. « Effect of Graphene Oxide and Graphite on Dry Sliding Wear Behavior of Polyester Composites ». Materiale Plastice 55, n^o 1 (30 mars 2018) : 102–10. http://dx.doi.org/10.37358/mp.18.1.4973.

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Graphene oxide and graphite filled polyester composites were prepared by using conventional melt-mixing methods in order to improve tribological performance of polyester. It was investigated friction stability, microhardness, friction coefficient, and specific wear rate of the composites in details. It was found that the presence of graphite and graphene oxide influenced friction coefficient and wear rate of the composites. Graphene oxide decreased wear rate with increasing of test speed and graphite decreased wear rate for composite for all speeds. Tribological performance of the polyester/graphene composites is mainly attributed to bigger thermal conductivity for graphene, which can easily dissipate the heat which appears during the friction process at bigger forces. The positive influence of graphite on coefficient of friction (COF) of the composites is the result of the clivage of graphite layers during the loadings due to van der Waals weak bonds between the graphite layers.

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Thema, F. T., M. J. Moloto, E. D. Dikio, N. N. Nyangiwe, L. Kotsedi, M. Maaza et M. Khenfouch. « Synthesis and Characterization of Graphene Thin Films by Chemical Reduction of Exfoliated and Intercalated Graphite Oxide ». Journal of Chemistry 2013 (2013) : 1–6. http://dx.doi.org/10.1155/2013/150536.

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Commercial flakes of graphite were prepared into functionalized graphene oxide (GO) by chemical treatment. After the exfoliation and intercalation of graphene into functionalized graphene oxide that formed stable colloidal dispersion in polar aprotic solvent, the reduction process was undertaken by continuous stirring with hydrazine hydrate. The reduced material was characterized by X-ray diffraction (XRD), attenuated total reflectance (ATR) FT-IR, ultraviolet visible (UV-vis), atomic force microscopy (AFM) and Raman spectroscopy which confirm the oxidation of graphite and reduction of graphene oxide into graphene sheet.

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Chong, S. W., Chin Wei Lai, Sharifah Bee Abd Hamid, F. W. Low et Wei Wen Liu. « Simple Preparation of Exfoliated Graphene Oxide Sheets via Simplified Hummer’s Method ». Advanced Materials Research 1109 (juin 2015) : 390–94. http://dx.doi.org/10.4028/www.scientific.net/amr.1109.390.

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Today, research on graphene and other two-dimensional sp2-hybridized carbon nanomaterials has tremendously impacted the areas of modern chemistry, physics, and materials science and engineering. The significant attraction of these materials can be attributed to the outstanding electrical, optical, electrochemical, and mechanical properties of graphene-like materials, especially in comparison to other carbon materials. In this manner, graphene oxide as a substrate for graphene-like materials reduction process is getting more and more interesting. Although early routes to these materials were challenging, significant advances in synthetic and processing methods have enabled access to high-quality exfoliated graphene oxide sheets in appreciable quantities. Herein, we introduced a simple and efficient method for the high-conversion preparation of graphene oxide using a simplified hummer’s method from large graphite flakes (an average flake size of 100 μm). One-pot chemical oxidation of graphite was carried out at room temperature for the preparation purpose. It was found that different degree of oxidation of graphite flakes could be realized by stirring graphite in a mixture of sulphuric acid and potassium permanganate under different oxidation durations, resulting in exfoliated graphene oxide sheets with large lateral dimension and area. The simplified Hummer’s method provides a facile approach for the preparation of large-area exfoliated graphene oxide sheets.

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N, Thangaraj. « Investigation on Structural, Optical, and Thermal Properties of Graphene Oxide (GO) Nanoparticles ». INTERANTIONAL JOURNAL OF SCIENTIFIC RESEARCH IN ENGINEERING AND MANAGEMENT 08, n^o 04 (6 avril 2024) : 1–5. http://dx.doi.org/10.55041/ijsrem30191.

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The aim of the study , A nanoparticles of graphene oxide (GO) was synthesized by modified Hummer’s method. A new approach to synthesis graphene is oxidizing graphite powder with mixture with concentrated Sulphuric acid (H2SO4), Sodium Nitrate (Na NO3) and Potassium permanganate (KMnO4), Currently,an improved method for the preparation of graphene Oxide was most common one. The Graphene Oxide (GO) was characterized by X-Ray diffractration, FT-IR Spectroscopy, UV Visible Spectroscopy , Raman Spectroscopy and TGA analysis. The X-ray diffractration (XRD) results of Graphene oxide nanoparticles was found to be 12.9 nm with a hexagonal crystal structure. Key Words: Graphene oxide, Hummer’s method,Graphite, X-ray diffratcration, FI-IR analysis,UV-Visible spectroscopy ,Raman spectroscopy and TGA-DTA analysis

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Liu, Li Lai, Mao Zhong An, Shan Chao Xing, Xiao Jun Shen, Chen Yang et Xin Long Xu. « Preparation of Graphene Oxide Based on Expanded Graphite ». Advanced Materials Research 881-883 (janvier 2014) : 1083–88. http://dx.doi.org/10.4028/www.scientific.net/amr.881-883.1083.

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Graphene oxide with high degree of oxidation and peelable has been prepared by two-step oxidation method used large flake graphite. The expanded graphite was prepared firstly and then prepared graphene oxide via further oxidation. The influence of oxidation time, oxidant dosage and high temperature reaction on the structure and degree of oxidation were studied. The morphology and structure of graphene oxide were characterized by X-ray diffraction, fourier transform infrared spectra, scanning electron microscope and transmission electron microscope. It was found that high degree of oxidation and large specific surface area graphene oxide was prepared at the ratio of sulfuric acid and expanded graphite was 75 mL : 1 g, the ratio of potassium permanganate and expanded graphite was 4 g : 1 g and the oxidation time at 35 °C was 24 h. This technology is simple without high-temperature reaction process, and solved the problem of low oxidation efficiency when used the large flake graphite as raw materials.

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Habte, Adere Tarekegne, et Delele Worku Ayele. « Synthesis and Characterization of Reduced Graphene Oxide (rGO) Started from Graphene Oxide (GO) Using the Tour Method with Different Parameters ». Advances in Materials Science and Engineering 2019 (15 août 2019) : 1–9. http://dx.doi.org/10.1155/2019/5058163.

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A new approach to synthesize graphene is oxidizing graphite powder with a mixture of H2SO4/H3PO4 acids and potassium permanganate. Parameters such as reaction time, reaction temperature, and amount of concentration were varied to study the degree of oxidation of graphite to graphene oxide. Currently, an improved method for the preparation of graphene oxide was the most common one. A mixture of H2SO4/H3PO4 (9 : 1 volume ratio) instead of only H2SO4 resulted in increased hydrophilic and oxidized GO without the emission of toxic gas, which differs from the traditional Hummers’ method. The graphene oxide (GO) was converted to reduced graphene oxide (rGO) by chemical reduction using ascorbic acid as the reducing agent. The GO and rGO were characterized by UV-visible spectroscopy, FTIR spectroscopy, and X-ray diffraction patterns. The result showed that treating graphite powder with potassium permanganate (1 : 9) and a mixture of concentrated H2SO4/H3PO4 acids at 50°C for 12 hours resulted in a better oxidation degree. The designed synthesis strategy could be easily controlled and is an alternative green approach for the production of graphene oxide and reduced graphene oxide.

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Lakshani, S. D. M., D. B. H. I. Bandara, R. C. L. De Silva, A. M. K. L. Abeykoon, M. H. T. Dulaj et I. R. M. Kottegoda. « Mass scale production and purification of graphite oxide from Sri Lankan vein graphite and spectroscopic characterization ». Sri Lankan Journal of Physics 24, n^o 2 (31 décembre 2023) : 98–109. http://dx.doi.org/10.4038/sljp.v24i2.8134.

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Discovery of graphene has enhanced attention on industrial scale production of graphene using natural graphite which involves oxidation followed by reduction processes. Aiming for the first time, mass scale production of graphite oxide from Sri Lankan vein graphite of natural purity 99.5% carbon, following an improved Hummer’s method was experimented at optimized conditions minimizing chemical, energy and time wastage. The present study further aimed at determination of pH and manganese ions on successive purification processes of graphite oxide. The X-ray diffraction spectroscopy (XRD), Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) characterizations were followed for verification of products. The wastewater produced from graphite oxide preparation process was systematically tested for Mn2+ ion using Atomic Absorption Spectroscopy (AAS). XRD peaks verified the formation of graphite oxide successfully through a complete oxidation of graphite. FTIR spectrum exhibited characteristic peaks related to typical graphite oxide while SEM shows the typical morphological features. XPS analysis verified complete removal of Mn from graphite oxide after purification. AAS analysis reveals entire removal of Mn after several washing cycles using only water. The investigation concludes that even mass scale production of quality graphite oxide is possible from Sri Lankan pure vein graphite which can subsequently be used to produce precious graphene and derivatives for various high-end applications.

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Yao, Yu Qin, Yin Jie Cen, Richard D. Sisson et Jian Yu Liang. « A Synthesize Protocol for Graphene Nanosheets ». Materials Science Forum 880 (novembre 2016) : 3–6. http://dx.doi.org/10.4028/www.scientific.net/msf.880.3.

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Chemical synthesis is cheap and easy to be tailored. Reduction of graphite oxide to form graphene nanosheets is a necessary step that determines yield, quality, chemical and surface properties of graphene nanosheets. In this report, the reduction of graphite oxides by chemical and thermal methods has been employed to convert graphite oxide synthesized by the same wet chemical method using KMnO4 and H2O2. The characterization results from the two reduction methods indicate that a combination of wet oxidation of graphite and thermal reduction method is an efficient and environmental friendly way to produce graphene.

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Kanabenja, Warrayut, et Pranut Potiyaraj. « Graphene/Thermoplastic Polyurethane Composites ». Key Engineering Materials 773 (juillet 2018) : 77–81. http://dx.doi.org/10.4028/www.scientific.net/kem.773.77.

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Thermoplastic polyurethane/graphene nanocomposites were successfully prepared by mixing masterbatches with neat polymers using the melt compounding process. Graphene was obtained from graphite by the chemical mean. Graphite was initially converted into graphite oxide which was then converted to graphene oxide. Graphene oxide was then reduced by L-ascorbic acid to obtain graphene. The effects of graphene addition on thermal and morphological properties of nanocomposite were studied by a differential scanning calorimeter, a thermal gravimetric analyzer and a scanning electron microscope. TPU/graphene nanocomposites showed higher melting temperature compared to TPU. On the other hand, heat of fusion of nanocomposites was lowered. TPU and TPU/graphene nanocomposites have two steps of decomposition. The first degradation of TPU occurred at higher temperature compared with nanocomposites but the second degradation showed the opposite results. The percentage of residue after thermal degradation of nanocomposites was lower than that of TPU. For surface morphology, nanocomposite exhibited the rougher surface comparing with TPU and well graphene dispersion in TPU phase was achieved. Nevertheless, there were some agglomeration of graphene.

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Mochizuki, Tomofumi, Yamato Hayashi, Jun Fukushima et Hirotsugu Takizawa. « Synthesis and Characterization of Ag/Graphene Nanocomposites by Solid-Liquid Sonochemical Reactions ». Materials Science Forum 804 (octobre 2014) : 119–22. http://dx.doi.org/10.4028/www.scientific.net/msf.804.119.

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In this study, Graphite Oxide (GO) and Ag/Graphene nanocomposites were synthesized by solid-liquid sonochemical reactions easily and briefly. GO was synthesized by means of Hummers method using sonication or stirring. From XRD patterns and FT-IR spectra, chemical and physical effects of ultrasound promoted the oxidation of Graphite. Ag/graphene nanocomposites were synthesized from GO and silver oxide by sonication. UV-vis spectra showed the peaks of Graphene oxide and Ag nanoparticle plasmon resonance absorption. EDX images and electron diffraction patterns confirmed Ag nanoparticles were decorated on Graphene sheets by ultrasound. Using sonication, GO and Ag/Graphene nanocomposites could be synthesized easily in short time.

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Kawata, Kazunori, Syunsuke Kawaki, Takako Nakamura, Yoshinori Koga et Masataka Hasegawa. « Fabrication of multi-layer graphene by repeated transfer ». AIP Advances 12, n^o 9 (1 septembre 2022) : 095110. http://dx.doi.org/10.1063/5.0100501.

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Multi-layer graphene was formed by repeated transfer onto a silicon oxide substrate, and changes in its doping characteristics were observed. The structure of multi-layer graphene was investigated in comparison with pyrolytic graphite with a turbostratic structure. Single-layer graphene is doped due to the influence of the silicon oxide substrate, and the influence of poly(methyl methacrylate) and water residue, which are used for the transfer, is small. Graphene in the first layer suppresses the influence of the silicon oxide substrate, and the second and subsequent layers are almost unaffected. By repeating the transfer and stacking, multi-layer graphene approaches ideal turbostratic graphite.

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Gauvin, Florent, Patrice Cousin et Mathieu Robert. « Effect of modified graphene oxide on the mechanical, thermal, and barrier properties of vinylester ». Journal of Composite Materials 52, n^o 28 (13 avril 2018) : 3853–64. http://dx.doi.org/10.1177/0021998318770730.

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Graphene, which is a one atom thick layer of graphite, has been considerably studied in the past decade due to its extraordinary physical properties. The development of new routes of synthesis facilitates the use of graphene in polymer nanocomposite. The addition of very small amounts (<1%) of graphene in a polymer matrix does not only increase its thermal and mechanical properties, but it would also enhance permeability, by limiting the diffusion of water through the material. Graphene-polymer nanocomposite would be an interesting alternative to conventional polymer nanocomposite such as nanoclay-polymer nanocomposite. In this study, graphene oxide is synthesized from graphite flakes, following the Tour method, and modified with silane to improve its compatibility with the polymer. Polymer nanocomposite made from vinylester resin and 0.5 wt% graphene oxide is prepared as well as other types of typically used polymer nanocomposite such as graphite flake, silica fume or nanoclay based composite. Samples are soaked in a water bath to study the water absorption of these nanocomposites. Mechanical property measurements and thermal analyses are performed to evaluate the benefit of using graphene oxide. Results show a significant enhancement of the mechanical and thermal properties with a graphene oxide content ten times lower than the one needed with conventional nanoparticles. Moreover, unlike nanoclay-based polymer nanocomposite, graphene oxide does not increase water absorption at saturation.

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Wang, Ziming, Yiyang Cao, Decai Pan et Sen Hu. « Vertically Aligned and Interconnected Graphite and Graphene Oxide Networks Leading to Enhanced Thermal Conductivity of Polymer Composites ». Polymers 12, n^o 5 (14 mai 2020) : 1121. http://dx.doi.org/10.3390/polym12051121.

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Natural graphite flakes possess high theoretical thermal conductivity and can notably enhance the thermal conductive property of polymeric composites. Currently, because of weak interaction between graphite flakes, it is hard to construct a three-dimensional graphite network to achieve efficient heat transfer channels. In this study, vertically aligned and interconnected graphite skeletons were prepared with graphene oxide serving as bridge and support via freeze-casting method. Three freezing temperatures were utilized, and the resulting graphite and graphene oxide network was filled in a polymeric matrix. Benefiting from the ultralow freezing temperature of −196 °C, the network and its composite occupied a more uniform and denser structure, which lead to enhanced thermal conductivity (2.15 W m−1 K−1) with high enhancement efficiency and prominent mechanical properties. It can be significantly attributed to the well oriented graphite and graphene oxide bridges between graphite flakes. This simple and effective strategy may bring opportunities to develop high-performance thermal interface materials with great potential.

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T, Remyamol, Pramod Gopinath et Honey John. « Phenylenediamine functionalized reduced graphene oxide/polyaniline hybrid : synthesis, characterization, improved conductivity and photocurrent generation ». RSC Adv. 4, n^o 56 (2014) : 29901–8. http://dx.doi.org/10.1039/c4ra03155e.

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Phenylenediamine functionalized reduced graphene oxide (GONH2) is designed and synthesized for the preparation of a polyaniline/reduced graphene oxide hybrid having better interactions than that of the unfunctionalized graphite oxide/polyaniline hybrid.

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Almasov, N., B. Kurbanova, T. Kuanyshbekov, K. Akatan, S. Kabdrakhmanova et K. Aimaganbetov. « Study of the structure and electrical properties of graphene oxide (GO) and graphene oxide+nanocellulose (GO+NC) ». Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 329, n^o 2 (3 octobre 2023) : 103–9. http://dx.doi.org/10.31643/2024/6445.21.

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Proton exchange membranes (PEMs) that function at elevated temperatures surpassing 100°C and exhibit exceptional mechanical, chemical, and thermochemical stability have garnered significant interest. This is primarily due to their practical utility in proton exchange membrane fuel cells (PEMFCs). In the present era, an extensive array of polymers and polymer-blended membranes have been scrutinized for their applicability in this domain. Each of these materials presents a set of advantages and disadvantages. However, the realm of PEMFCs is still in search of the perfect membrane endowed with distinct properties. Graphene oxide, a two-dimensional substance arising from the oxidation of graphite, has manifested itself as a promising candidate. Oxygen (O) functional groups are incorporated within the sp2 carbon (C) plane of the oxidized graphite, forming graphene oxide. This material can be synthesized by exfoliating graphite oxide, a three-dimensional carbon-based compound, into layered sheets using ultrasonic or mechanical agitation. The presence of multiple reactive oxygen functional groups renders graphene oxide suitable for a diverse array of applications, such as composite polymers, energy conversion materials, environmental safeguards, sensors, transistors, and optical components. This versatility is attributable to its outstanding electrical, mechanical, and thermal properties. Among the various methodologies for graphene oxide synthesis, the modified Hammer method stands out for its simplicity, cost-effectiveness, and high yield. This research delves into the structural analysis of graphene oxide obtained through the Hammer method, utilizing commercially available graphite. The study involves the creation of membranes based on carboxymethylcellulose (NC) that integrate dispersed graphene oxide (GO) sheets. These novel membranes, as well as pristine graphene oxide, were subjected to a comprehensive array of analytical techniques including XRD, XPS, Raman, FTIR, and SEM microscopy. Additionally, electrophysical characterizations were undertaken employing electrochemical impedance spectroscopy (EIS) measurements. The investigation uncovered that the introduction of NC into the graphene oxide matrix significantly enhances the electron conductivity of the composite membrane. Simultaneously, the presence of graphene oxide contributes to the mechanical robustness and thermomechanical stability of the membrane structure. The principal impetus behind this article lies in furnishing vital insights into the physical and structural attributes of graphene oxide membranes relevant to their deployment in hydrogen energy applications.

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Amandeep, Kaur Rozi, Singh Harminder, Kamal Kaur Randhawa Deep et Sheetal Anu. « Reduced graphene oxide synthesis by hummer method ». i-manager's Journal on Material Science 11, n^o 4 (2024) : 1. http://dx.doi.org/10.26634/jms.11.4.20557.

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In this study, Graphite Oxide (GO) film with a 2-D structure was successfully synthesized via the Hummer method. The GO film was further reduced by hydrazine to form a few layers of graphene. The graphite oxide and reduced graphene oxide synthesized in this study were characterized by Scanning Electron Microscopy (SEM), Raman spectroscopy, and XRD analysis. A low-cost method using simple chemicals was employed to synthesize GO films with high conductivity on a large scale. The synthesized reduced graphene oxide can serve as an excellent material for various applications due to its lower cost and higher thermal, mechanical, and electrical conductivity. Large surface area graphene-based sensors and solar cells can efficiently replace expensive Carbon Nanotubes (CNTs).

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Hu, Zhong Liang, Yi Feng Chen, Na Li, Wei Zhang, Han Chen et Wen Qiang Gong. « Preparation of Graphene/Pd Nanoparticle Composites and their Hydrogen Storage ». Advanced Materials Research 772 (septembre 2013) : 349–54. http://dx.doi.org/10.4028/www.scientific.net/amr.772.349.

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Pd (en)2Cl2can be intercalated into graphite oxide layers with high efficiency. The Pd (en)22+intercalated graphite oxide was firstly synthesized by mixture reaction of Pd (en)2Cl2and graphite oxide, then it was reduced in solution with NaBH4and thereafter the graphene/Pd nanosized particle composites were obtained. The graphene composites were characterized by XRD, FE-SEM, TEM, ICP and N2adsorption tests and their H2storage was also measured. The results show that the composites contain a large amount of Pd and have a regular mesoporous structure, and Pd particles with a diameter of 2-6 nm are evenly dispersed between graphene sheets and pillar the graphene sheets. The BET surface area of the composites is 230 m2/g and their H2storage reaches 3.4 wt.% at 77K and 0.11 MPa.

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Jiang, Yan Li, Mei Tian, Ying Hui Yu, Jia Yao Liu et Shuang Liu. « Preparation and Property of Reduced Graphene for Hummers ». Key Engineering Materials 591 (novembre 2013) : 301–4. http://dx.doi.org/10.4028/www.scientific.net/kem.591.301.

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Graphene material has ideal lattice structure and unique electrical, optical and other properties. In the electronics, composite materials, and other fields it has a broad application prospect. In this paper, using the Hummers method, to prepare oxidized graphite and graphene , to optimize the conditions of the preparation of graphite oxide. With two kinds of reductors, glucose and hydrazine hydrate, reduction graphite oxide, and dropped silver ions in the process of reduction. Using XRD, SEM and Raman spectra to character and analyze the products. The result showed that the graphite and silver ions in the oxidation reaction process were both restored by glucose, hydrazine hydrate. This structure that silver nanoparticles are uniformly distributed in the graphene sheet layers, can effectively prevent the reunion of graphene layers, and also upset the rules of the pile of the graphene layers.

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Hou, Zhao Xia, Yin Zhou, Shao Hong Wang, Mei Han Wang, Xiao Dan Hu, Li Di Zhou et Guang Bin Li. « Preparation and Characterization of Graphene by Oxidation-Reduction Method ». Advanced Materials Research 807-809 (septembre 2013) : 2805–8. http://dx.doi.org/10.4028/www.scientific.net/amr.807-809.2805.

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Graphene was prepared by using hydrazine hydrate to reduce the exfoliated graphite oxide nanosheets in the aqueous colloidal suspension. The prepared graphene were characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction analysis (XRD) and scanning electron microscope (SEM), respectively. The results showed that part of oxygen containing groups of the exfoliated graphite oxide nanosheets disappeared and the conjugated p bond recovered after reduction. The thickness and size of the graphene nanosheets decreased.

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Menchaca-Campos, Carmina, César García-Pérez, Iván Castañeda, Miguel A. García-Sánchez, René Guardián et Jorge Uruchurtu. « Nylon/Graphene Oxide Electrospun Composite Coating ». International Journal of Polymer Science 2013 (2013) : 1–9. http://dx.doi.org/10.1155/2013/621618.

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Graphite oxide is obtained by treating graphite with strong oxidizers. The bulk material disperses in basic solutions yielding graphene oxide. Starting from exfoliated graphite, different treatments were tested to obtain the best graphite oxide conditions, including calcination for two hours at 700°C and ultrasonic agitation in acidic, basic, or peroxide solutions. Bulk particles floating in the solution were filtered, rinsed, and dried. The graphene oxide obtained was characterized under SEM and FTIR techniques. On the other hand, nylon 6-6 has excellent mechanical resistance due to the mutual attraction of its long chains. To take advantage of the properties of both materials, they were combined as a hybrid material. Electrochemical cells were prepared using porous silica as supporting electrode of the electrospun nylon/graphene oxide films for electrochemical testing. Polarization curves were performed to determine the oxidation/reduction potentials under different acidic, alkaline, and peroxide solutions. The oxidation condition was obtained in KOH and the reduction in H2SO4solutions. Potentiostatic oxidation and reduction curves were applied to further oxidize carbon species and then reduced them, forming the nylon 6-6/functionalized graphene oxide composite coating. Electrochemical impedance measurements were performed to evaluate the coating electrochemical resistance and compared to the silica or nylon samples.

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Hao, Yu-Chuan, Nurzal Nurzal, Hung-Hua Chien, Chen-Yu Liao, Fei-Hong Kuok, Cheng-Chen Yang, Jian-Zhang Chen et Ing-Song Yu. « Application of Atmospheric-Pressure-Plasma-Jet Modified Flexible Graphite Sheets in Reduced-Graphene-Oxide/Polyaniline Supercapacitors ». Polymers 12, n^o 6 (28 mai 2020) : 1228. http://dx.doi.org/10.3390/polym12061228.

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In this study, flexible and low-cost graphite sheets modified by atmospheric pressure plasma jet are applied to reduced-graphene-oxide/polyaniline supercapacitors. Surface treatment by atmospheric pressure plasma jet can make the hydrophobic surface of graphite into a hydrophilic surface and improve the adhesion of the screen-printed reduced-graphene-oxide/polyaniline on the graphite sheets. After the fabrication of reduced-graphene-oxide/polyaniline supercapacitors with polyvinyl alcohol/H2SO4 gel electrolyte, pseudo-capacitance and electrical double capacitance can be clearly identified by the measurement of cyclic voltammetry. The fabricated supercapacitor exhibits specific capacitance value of 227.32 F/g and areal capacitance value of 28.37 mF/cm2 with a potential scan rate of 2 mV/s. Meanwhile, the capacitance retention rate can reach 86.9% after 1000-cycle cyclic voltammetry test. A light-emitting diode can be lit by the fabricated reduced-graphene-oxide/polyaniline supercapacitors, which confirms that the supercapacitors function well and can potentially be used in a circuit.

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Articles de revues sur le sujet « Oxyde de graphène »

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