Synthesis and Properties of Graphene and Graphene Oxide-Based Polymer Composites
01 Jan 2019-pp 175-201
TL;DR: In this article, the progress of fabrication of graphene and graphene oxide-based polymer composites with different polymer matrixes such as poly(vinylidene fluoride) (PVDF), epoxy and polyurethane (PU) is discussed.
Abstract: Graphene and graphene oxide-based polymer composites have remarkable interests over the last one decade due to their excellent mechanical, thermal and electrical properties. The nanometric synthesized fillers with polymeric matrix enhance the structural, morphological and functional properties of the composite materials, and this can be prepared by both ex situ/in situ processes. However, the presence of graphene and graphene oxide even at a very small amount of loadings can give major reinforcement to the final properties of the composites. In addition, graphene is one of the finest material of choice for electronic and energy storage applications in the form of polymer–graphene composites. This chapter reviews and explores the progresses of fabrication of graphene and graphene oxide-based polymer composites with different polymer matrixes such as poly(vinylidene fluoride) (PVDF), epoxy and polyurethane (PU) with special emphasis on their modification, surface alternation and their properties from the scientific literature.
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TL;DR: In this paper, a polysulfone-iron oxide/graphene oxide composite hollow fiber membranes were fabricated, which showed oxygen-enriched functional groups and improved hydrophilicity.
Abstract: Phenolic compounds are the harmful water contaminants, which severely affect living beings. Therefore, it is essential to remove the phenolic compounds, e.g., 2,4-dichlorophenol (2,4-DCP) from water sources. In this study, polysulfone-iron oxide/graphene oxide composite hollow fiber membranes were fabricated, which showed oxygen-enriched functional groups and improved hydrophilicity. With 0.5 wt.% iron oxide/graphene oxide nanohybrid in polysulfone hollow fiber membranes, remarkably high pure water flux was measured (339.8 ± 9.9 L/m2h). The improved antifouling property was achieved with a flux recovery of 95.8 %. The 2,4-DCP separation efficiency was measured to be 96.5 ± 1.6 % and 70.5 ± 2.1 % from the contaminated lab water and lake water, respectively. The separation efficiency of the composite membranes remained almost the same at the 5th filtration cycle. These results indicated that the polysulfone-iron oxide/graphene oxide composite hollow fiber membranes are promising in the efficient removal of the harmful 2,4-DCP from water sources.
27 citations
Journal Article•
TL;DR: In this article, reduced graphene oxide was added into poly(vinylidene fluoride) to fabricate the piezoelectric nanocomposite films, and the open-circuit voltage and electrical power harvesting experiments were conducted.
Abstract: Piezoelectric energy harvesters can be used to convert ambient energy into electrical energy and power small autonomous devices. In recent years, massive effort has been made to improve the energy harvesting ability in piezoelectric materials. In this study, reduced graphene oxide was added into poly(vinylidene fluoride) to fabricate the piezoelectric nanocomposite films. Open-circuit voltage and electrical power harvesting experiments showed remarkable enhancement in the piezoelectricity of the fabricated poly(vinylidene fluoride)/reduced graphene oxide nanocomposite, especially at an optimal reduced graphene oxide content of 0.05 wt%. Compared to pristine poly(vinylidene fluoride) films, the open-circuit voltage, the density of harvested power of alternating current, and direct current of the poly(vinylidene fluoride)/reduced graphene oxide nanocomposite films increased by 105%, 153%, and 233%, respectively, indicating a great potential for a broad range of applications.
3 citations
TL;DR: In this article , a method of synthesis of reduced graphene oxide granules, which can be used as nanofiller in polymer matrix, is presented, and the material structural-morphology is characterized by XRD, TGA, UV, Raman and SEM.
Abstract: Graphene has attracted a great attention in the recent years of research innovations mainly due to its unique properties and in particular, its structural composition of one-atom thick sheet of hexagonally arrayed sp2 carbon atoms. This article focuses on a method of synthesis of graphene oxide granules, which can be use as nanofiller in polymer matrix. Polymer nanocomposites reinforced with graphene nanofillers have better mechanical, thermal and electrical properties than pure polymer materials. Some corrugated spherical structures/granules of reduced graphene oxide were produced by a dispersion/drying method. For this purpose the reduced graphene oxide suspension produced in the laboratory by an improved method was mixed on a magnetic stirring and delivered by a peristaltic pump to the granulation zone at a speed 10-20 ml/min. The granulation zone temperature was kept within 40-150°C. The suspension was dispersed by compressed air up to 3 atmospheres. The produced granules were accumulated in a receiver, and dried in the vacuum oven to remove residues of solvents used in the process. The engineered reduced Graphene oxide were analyzed and the material structural-morphology was characterized by XRD, TGA, UV, Raman and SEM.
TL;DR: In this article , a fully imidized polyetherimide (PEI) resin is utilized as the continuous phase with inclusion of unfunctionalized exfoliated graphite (UFG).
Abstract: Abstract Light-weighting vehicular components through adoption of light-metal structural alloys holds promise for reducing the fuel consumption of internal combustion engine vehicles and increasing the range of battery electric vehicles. However, the alloyed microstructure and surface precipitates of aluminum alloys render these materials susceptible to corrosion under modest excursions from neutral pH. Traditional chromium-based anodic passivation layers are subject to increasingly stringent environmental regulations, whereas options for sacrificial cathodic films are sparse for electropositive metals. While hybrid nanocomposite coatings have shown initial promise, mechanistic underpinnings remain poorly understood. Here, a fully imidized polyetherimide (PEI) resin is utilized as the continuous phase with inclusion of unfunctionalized exfoliated graphite (UFG). A comprehensive investigation of the mechanisms of corrosion protection reveals key fundamental design principles underpinning corrosion inhibition. First, strong interfacial adhesion, which for PEI is facilitated by binding of imide carbonyl moieties to Lewis acidic sites on Al surfaces. Second, the miscibility of ion-impervious nanoscopic UFG fillers and stabilization of a substantial interphase region at UFG/PEI boundaries that result in minimizing the free volume at the filler/polymer interface. Finally, extended tortuosity of ion diffusion pathways imbued by the below-percolation-threshold 2D fillers. These three design principles help govern and modulate ion transport from electrolyte/coating interfaces to the coating/metal interface and are crucial for the extended preservation of barrier properties. The results suggest an approach to systematically activate multiple modes of corrosion inhibition through rational design of hybrid nanocomposite coatings across hard-to-abate sectors where light metal alloys are likely to play an increasingly prominent role.
References
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TL;DR: Monocrystalline graphitic films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands and they exhibit a strong ambipolar electric field effect.
Abstract: We describe monocrystalline graphitic films, which are a few atoms thick but are nonetheless stable under ambient conditions, metallic, and of remarkably high quality. The films are found to be a two-dimensional semimetal with a tiny overlap between valence and conductance bands, and they exhibit a strong ambipolar electric field effect such that electrons and holes in concentrations up to 10 13 per square centimeter and with room-temperature mobilities of ∼10,000 square centimeters per volt-second can be induced by applying gate voltage.
55,532 citations
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TL;DR: Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena can now be mimicked and tested in table-top experiments.
Abstract: Graphene is a rapidly rising star on the horizon of materials science and condensed-matter physics. This strictly two-dimensional material exhibits exceptionally high crystal and electronic quality, and, despite its short history, has already revealed a cornucopia of new physics and potential applications, which are briefly discussed here. Whereas one can be certain of the realness of applications only when commercial products appear, graphene no longer requires any further proof of its importance in terms of fundamental physics. Owing to its unusual electronic spectrum, graphene has led to the emergence of a new paradigm of 'relativistic' condensed-matter physics, where quantum relativistic phenomena, some of which are unobservable in high-energy physics, can now be mimicked and tested in table-top experiments. More generally, graphene represents a conceptually new class of materials that are only one atom thick, and, on this basis, offers new inroads into low-dimensional physics that has never ceased to surprise and continues to provide a fertile ground for applications.
35,293 citations
TL;DR: The extremely high value of the thermal conductivity suggests that graphene can outperform carbon nanotubes in heat conduction and establishes graphene as an excellent material for thermal management.
Abstract: We report the measurement of the thermal conductivity of a suspended single-layer graphene. The room temperature values of the thermal conductivity in the range ∼(4.84 ± 0.44) × 103 to (5.30 ± 0.48) × 103 W/mK were extracted for a single-layer graphene from the dependence of the Raman G peak frequency on the excitation laser power and independently measured G peak temperature coefficient. The extremely high value of the thermal conductivity suggests that graphene can outperform carbon nanotubes in heat conduction. The superb thermal conduction property of graphene is beneficial for the proposed electronic applications and establishes graphene as an excellent material for thermal management.
11,878 citations
TL;DR: The direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers is reported, and two different methods of patterning the films and transferring them to arbitrary substrates are presented, implying that the quality of graphene grown by chemical vapours is as high as mechanically cleaved graphene.
Abstract: Problems associated with large-scale pattern growth of graphene constitute one of the main obstacles to using this material in device applications. Recently, macroscopic-scale graphene films were prepared by two-dimensional assembly of graphene sheets chemically derived from graphite crystals and graphene oxides. However, the sheet resistance of these films was found to be much larger than theoretically expected values. Here we report the direct synthesis of large-scale graphene films using chemical vapour deposition on thin nickel layers, and present two different methods of patterning the films and transferring them to arbitrary substrates. The transferred graphene films show very low sheet resistance of approximately 280 Omega per square, with approximately 80 per cent optical transparency. At low temperatures, the monolayers transferred to silicon dioxide substrates show electron mobility greater than 3,700 cm(2) V(-1) s(-1) and exhibit the half-integer quantum Hall effect, implying that the quality of graphene grown by chemical vapour deposition is as high as mechanically cleaved graphene. Employing the outstanding mechanical properties of graphene, we also demonstrate the macroscopic use of these highly conducting and transparent electrodes in flexible, stretchable, foldable electronics.
10,033 citations
TL;DR: An improved method for the preparation of graphene oxide (GO) is described, finding that excluding the NaNO(3), increasing the amount of KMnO(4), and performing the reaction in a 9:1 mixture of H(2)SO(4)/H(3)PO(4) improves the efficiency of the oxidation process.
Abstract: An improved method for the preparation of graphene oxide (GO) is described. Currently, Hummers’ method (KMnO4, NaNO3, H2SO4) is the most common method used for preparing graphene oxide. We have found that excluding the NaNO3, increasing the amount of KMnO4, and performing the reaction in a 9:1 mixture of H2SO4/H3PO4 improves the efficiency of the oxidation process. This improved method provides a greater amount of hydrophilic oxidized graphene material as compared to Hummers’ method or Hummers’ method with additional KMnO4. Moreover, even though the GO produced by our method is more oxidized than that prepared by Hummers’ method, when both are reduced in the same chamber with hydrazine, chemically converted graphene (CCG) produced from this new method is equivalent in its electrical conductivity. In contrast to Hummers’ method, the new method does not generate toxic gas and the temperature is easily controlled. This improved synthesis of GO may be important for large-scale production of GO as well as the ...
9,812 citations