We report on a new counter electrode for dyesensitized solar cells dscs, which is prepared using layerbylayer assembly of negatively charged graphene oxide and positively charged poly. Graphene composite materials have been used to increase discharge rates, energy densities, and cycle performance in anodes used in lithium ion batteries. For instance, for an ego content of 2 wt %, the exothermic crosslinking dsc peak upon heating at 10 cmin shifted 6 c. Thermal analysis of the improved hummers synthesis of. Preparation of graphene oxidebased hydrogels as efficient. The method of physical mixture was efficient to obtain the polyaniline graphene oxide composites. One of the most commonly used derivatives of graphene is graphene oxide go.
It acts as a reducing agent for the go as well as capping agent allowing the formation of titanium dioxide nanoparticles with a narrow size distribution 20 nm. In this work, the go nanosheets were prepared by a chemical exfoliation technique. Avrami equation was used to describe the isothermal crystallization kinetics and melting behavior. Effects of graphene oxide and chemically reduced graphene oxide on. Graphene, a new twodimensional carbon nanomaterial and a fundamental building block for graphitic materials, has been the hotspot in multidisciplinary field owing to its high surface area surfacemass, excellent electrical behavior, and thermal properties 26.
Preparation and characterization of insensitive hmx. Graphenebased inorganic nanocomposites have emerged as a rising star on the horizon of engineering and materials science. A wellstudied nanofiller because of its distinct properties and wide range of applications, graphene oxide go proves to be a good choice in the. Ten minutes of magnetic stirring at 200 r pm yielded an inhomo geneous br own suspension. D341808 standard test method for transition temperatures and enthalpies of fusion and crystallization of polymers by differential scanning calorimetry. Such smart nanomaterials with improved performance have attracted great attention due to its ability to combine the. The maximally oxidized bulk product is a yellow solid with c. Paper open access synthesis and characterization of. Therefore, it is advisable to ask a vendor about the ph of the. Xrd, ftir, dsc, sem, and uvvisible studies were performed on the prepared nanocomposite polymer films. Electrochemically reduced graphene oxide multilayer films. Graphene oxide is being used in energy, optical, electronic and sensor devices due to its unique properties. Melting and crystallization of the reduced graphene oxide polyethyleneterephthalate composite was studied by the differential scanning calorimetry method, and the rheological test was carried out by.
Dynamic mechanical analysis dma, thermomechanical analysis tma and differential scanning calorimetry dsc were used in order to assess the thermal behaviour of polyester composites with graphene oxide and graphite. Reduced graphene oxideinduced polyethylene crystallization in solution and nanocomposites shan cheng, xi chen, y. Herein, we unveiled the differential distribution of go in lobules in the liver, with a higher amount surrounding portal. The first three methods can produce graphene with a. Synthesis variables were optimized according to a thickness value, calculated using a homemade excelvba application. The acidic nature ph23 of the unwashed graphene oxide will significantly deteriorate the results of its applications. Here, an ideal dielectric epoxy nanocomposite with. Reported results show a catalytic activity of graphene oxide ego on this reaction, comparable to that one already described in the literature for curing of benzoxazine. Since the discovery of graphene, 1,2,3 immense efforts have been focused on graphene oxide go, 4,5 since it is the most promising precursor for obtaining large quantities of this unique material and because go is a useful material on its own right.
Thermal gravity analysis for the study of stability of. Pdf synthesis of reduced graphene oxide with adjustable. It can be produced by micromechanical exfoliation of highly ordered pyrolytic graphite, epitaxial growth, chemical vapor deposition, and the reduction of graphene oxide go. The nonisothermal differential scanning calorimetry dsc was used to study the cure kinetics of ve and 0. Tga spectra of graphite, graphene oxide, and grapheneag composite films. Graphene oxide go and graphene g have become two of the most interesting nanomaterials due to their unique properties i. The triethanolamine tea used in the process has two roles. Formation of composite polyaniline and graphene oxide by.
Thermally conductive polymeric composites are highly promising in current energy devices such as lightemitting diodes, integrated circuits, and solar cells to achieve appropriate thermal management. Transmission electron microscopy tem micrographs show. Thermal transport in graphene oxide from ballistic. In figure 1a the tgdsc thermograms of the thermal reduction of pure. In one of the first studies illustrating this property, researchers measured the loss of weight within a containing initially filled with alcohol before and after it was sealed with a graphene. The acidic nature ph23 of the unwashed grapheme oxide will significantly deteriorate the results of its applications. Twentyfive milligrams of the graphene oxide powder was placed in a cup and 200 ml deionized water was then added. Graphene oxide can be visualized as individual sheets. The morphology, composition, thermal decomposition characteristic were characterized by scanning electron microscopy sem, x. In fact, for an ocb content of 2 wt %, the crosslinking dsc peak can be shifted. It is proven that redox method is a promising way to synthesize go films on a large scale.
The effects of metal complexes of nanographene oxide to. Graphene oxide and graphene reinforced pmma bone cements. Thermogravimetric analysis and differential scanning calorimetry tgdsc investigation and. Pdf thermal reduction study of graphene oxide paper. Synthesis of reduced graphene oxide with adjustable. Dsc scans show a catalytic activity of graphene oxide ego on the. The improved hummers synthesis of graphene oxide go from graphite is investigated to monitor how the functional groups form during the synthesis steps.
The resulting suspensions were further treated with a. From fundamentals to applications article pdf available in journal of physics condensed matter 271. Isothermal crystallization kinetics of polylactic acid. Thermal analysis of the nanocomposite polymer films was analyzed by dsc. Sigmaaldrich offers a number of graphene oxide products. These unique properties could be of great value for creating advanced biomaterials i. Li, department of materials science and engineering, drexel university, philadelphia, pennsylvania 19104, united states department of civil, architectural and environmental engineering, drexel university, philadelphia. The optimization of both the chemical vapor deposition cvd synthesis method to prepare graphene and the improved hummers method to prepare graphite oxide is reported.
Pdf preparation and characterization of graphene oxide. Here, graphene oxide go was used as filler in pan matrix, the structure evolution of gopan composite was studied during oxidative stabilization. Here we show that some bulk solid go samples can undergo explosive decomposition when small samples are heated slowly in inert gas environments, while others do not. Explosive thermal reduction of graphene oxidebased. A study on preparation of modified graphene oxide and. Other potential benefits of using graphene composite anodes in lithium ion batteries include increased battery. A major challenge for many industries wanting to adopt 3d printing technologies for rapid prototyping, customized parts, and lowvolume manufacturing depends on the availability and functionality of the input materials to suit specific requirements. The preliminary graphene oxide produced by hummer method has normally a ph value of from 2 to 3 if no washing step is involved in the entire production process. Graphite oxide, formerly called graphitic oxide or graphitic acid, is a compound of carbon, oxygen, and hydrogen in variable ratios, obtained by treating graphite with strong oxidizers. Effect of graphene oxide as a filler material on the mechanical properties of lldpe nanocomposites show all authors. Metal complexes of nanographene oxide have an obvious effect on the thermal decomposition of energy materials. Structurally, graphene oxide can be visualized as a graphene sheet with its basal plane decorated by oxygencontaining. Comprehensive characterizations of the properties of go films were conducted. Differential scanning calorimetry dsc was carried out on a q20 ta instruments, usa with a.
Selfassembled boron nitride nanotube reinforced graphene. Graphene materials and their use in dyesensitized solar cells. Raman spectroscopy has shown that william blythes graphene oxide is fully oxidised with an idig ratio of about 1, which is fairly typical for graphene oxide. For email marketing you can trust email marketing you can trust.
In order to quickly apply it to propellants, the thermal decomposition behaviors of fox7 should be optimized. The metal dsc hermetic sample pan was torn into two parts, the reference pan was displaced and graphenederived powder was spread throughout the cell fig. However, unlike its counterpart graphene the thermal transport properties of. These graphene oxides have important applications in areas related to. Preparation and characterization of graphene oxide reduced. Graphene oxide is the oxidized form of graphene produced by oxidizing crystal graphite with a mixture of sulfuric acid, sodium nitrate, and potassium permanganate the hummers method.
Effect of morphology and defectiveness of graphenerelated. Xrd revealed the amorphous nature of the prepared films. Graphene oxide go has attracted attention for its applications in biomedicine, especially as a nanocarrier. Thermal reduction of graphene oxide or graphite oxide go is an important processing step in the fabrication of many graphenebased materials and devices. Graphene oxide go nanoparticles were incorporated in pvapvp blend polymers for the preparation of nanocomposite polymer films by the solution cast technique. Synthesis of graphene oxide go by modified hummers. Over the span of years, improvements over various synthesis methods of graphene are constantly pursued to provide safer and more effective alternatives. Differential scanning calorimetry was used to highlight this effect through the increase in thermal stability. Graphene oxide can be reduced by chemical, electrochemical, or thermal means. Preparation and characterization of graphene oxide. Our graphene oxide based products were obtained after steps of repetitive washing with a large amount of distilled water.
Graphene has attracted great interest for its excellent mechanical, electrical, thermal and optical properties. Graphene oxide go has recently attracted great attention due to its unique chemical and physical properties. Structural and electrical properties of graphene oxide. Tga spectra of graphite, graphene oxide, and graphenea. Graphene oxide and oxidized carbon black as catalyst for. Reduction of graphene oxide was performed as follows. Graphene can be obtained in the form of reduced graphite oxide. Solubility measurement revealed that the crosslinking degree increased, while the cyclization degree of stabilized films decreased after go incorporation. Graphene oxide go films with twodimensional structure were successfully prepared via the modified hummer method. Pdf nonisothermal curing kinetics of biocomposite from. The effect of the filler on the crystallization behavior and thermal properties of scpla was investigated by using differential scanning calorimetry dsc. Preparation of graphene oxidebased hydrogels as efficient dye adsorbents for wastewater treatment haiying guo1,2, tifeng jiao1,2,3, qingrui zhang2, wenfeng guo2, qiuming peng1 and xuehai yan3 abstract graphene oxide go sheets exhibit superior adsorption capacity for removing organic dye pollutants from an aqueous environment. Effect of graphene oxide as a filler material on the. Therefore, it is advisable to ask a vendor about the ph of the graphene oxide before buying it.
Though the extraction of graphene through hummers method is one of the oldest techniques yet it is one of the most suitable methods for the formation of bulk graphene. Tem and dfm analyses showed that go sheets prepared in this study had single and double lamellar layer. Graphenebased metal oxide composites are promising materials due to their unique properties besides forthcoming technological applications. Structure evolution mechanism of polyacrylonitrile films. The structural and optical properties of the asprepared go nanosheets were characterized by raman, ftir, uvvis and photoluminescence spectroscopy. Optimization of the synthesis procedures of graphene and. Here we report the preparation and characterization of graphene oxide paper, a freestanding carbonbased membrane material made by flowdirected assembly of individual graphene oxide sheets. Copper and nickel were used as catalysts in the cvdgraphene synthesis, ch4 and h2being used as precursor gases. Graphene oxide go was synthesized and nanocomposites were prepared using different contents of the go and vinyl ester resin ve. Synthesis of graphene oxide scientific research publishing. To achieve these, samples are taken after every preparation step and analyzed with tgdtams, ftir, xrd and semedx techniques. However, the introduction of traditional thermoconductive fillers into a polymer usually results in low thermal conductivity enhancement. Effects of graphene oxide and chemically reduced graphene oxide. Similarly, graphene oxide membranes have a welldocumented gas separation ability that prevents any vapor molecules from passing through the membrane.
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