Graphite Oxide Nanocomposites Research Articles

One-step synthesis of Fe3O4@C/reduced-graphite oxide nanocomposites for high-performance lithium ion batteries

In this paper, we propose a facile one-step strategy to prepare Fe3O4@amorphous carbon/reduced graphite oxide nanocomposites (FCRGs) under hydrothermal conditions. A transmission electron microscopy image has shown that the as-formed Fe3O4 nanoparticles coated with a layer of amorphous carbon are wrapped by reduced graphite oxide (r-GO) sheets. The diameter of Fe3O4 nanoparticles is less than 50nm. N2 adsorption/desorption isotherms indicate that the specific surface area of FCRG is 31.6m2/g with porous structure. FCRG exhibits improved cycling stability and rate performances as a potential anode material for high-performance lithium ion batteries.

Preparation and characterization of maleated polylactide-functionalized graphite oxide nanocomposites

Organically dispersible graphene nanosheets were fabricated by amine surfactant intercalated graphite oxide (GOAs) with ultrasonication below room temperature. Subsequently, GOAs filled nanocomposites of polylactide grafted with maleic anhydride (PLAgMA) were prepared directly by solution blending. The compatibilization effects provided by the functionalization of both constituents and their influence on the structure and properties of the final nanocomposites in different compositions were investigated. The interactions and structural morphology of the nanocomposites were examined by Fourier transform infrared spectroscopy, X-ray diffraction, scanning and transmission electron microscopy. Thermal, dynamic-mechanical and conductive properties of these nanocomposites were investigated as a function of GOAs content. The detailed morphological and X-ray diffraction results revealed that the degree of GOAs dispersion enhanced with maleated PLA. Study of the dynamic-mechanical properties showed that both the storage modulus G’ and the loss modulus G” are very sensitive to the microstructure of the nanocomposite. The thermal properties of the nanocomposites were significantly influenced by the GOAs content due to the shielding and nucleating effect of exfoliated layers. Both the thermal and electrical conductivities showed substantial improvements with increasing GOAs content. The overall results pointed to the compatibilization synergy of GO functionalization and PLA maleation.

Synthesis of titanium dioxide–reduced graphite oxide nanocomposites and their photocatalytic performance

Chemically bonded titanium dioxide (TiO2)–reduced graphite oxide (RGO) composites have been successfully prepared with graphite oxide and peroxotitanium complex by low-temperature liquid reaction. The prepared TiO2 nanoparticles with diameters of about 10 nm consisted of anatase phase and a slight amount of brookite phase. In the TiO2–RGO composites, TiO2 nanoparticles were uniformly dispersed on the RGO surface from the scanning electron microscopy images. The as-prepared TiO2–RGO composites exhibited much higher efficiency in the degradation of methylene blue under ultraviolet light irradiation compared with pure TiO2 nanoparticles. In addition, the influences of the RGO content in the TiO2–RGO composites on the photocatalytic degradation activity were also researched.

A novel strategy for making poly(vinyl alcohol)/reduced graphite oxide nanocomposites by solvothermal reduction

Poly(vinyl alcohol) (PVA)/reduced graphite oxide (rGO) nanocomposites were synthesized by solvothermal reduction of graphite oxide (GO) in the presence of PVA. The solvent, the mixed dimethyl sulfoxide (DMSO)-dimethylformamide (DMF), could act not only as a reducing agent but also as a good stabilizer, which achieved effectively reduction of GO in the PVA matrix and avoided the agglomeration of rGO during reduction. A 53.0% increase in tensile strength and 52.6% improvement of Young’s modulus were achieved by addition of 3wt% of rGO. Furthermore, a significant improvement of thermal stability was observed for the PVA/rGO nanocomposites.

PP/PP‐g‐MAH/layered expanded graphite oxide nanocomposites prepared via masterbatch process

The following article from the Journal of Applied Polymer Science, “PP/PP-g-MAH/layered expanded graphite oxide nanocomposites prepared via masterbatch process,” by Jun Bian, Xiao Wei Wei, Hai Lan Lin, I Ta Chang, and Erol Sancaktar, published online on 10 July 2012 in Wiley Online Library (wileyonlinelibrary.com), and in Volume 128, pp. 600–610, has been withdrawn by agreement between the journal's editors and Wiley Periodicals, Inc. The action has been agreed due to unacknowledged overlap between Figure 4 in the above paper and Figure 2a in Composites Science and Technology, Volume 67 (2007), p. 2528, and the apparent misrepresentation of the material depicted therein. The publisher acknowledges that co-authors I Ta Chang and Erol Sancaktar are not responsible for the issues associated with this article.

Fabrication of polymer/microwave‐reduced graphite oxide nanocomposites by ball‐milling assisted wet compounding

AbstractMicrowave‐induced reduction of graphite oxide (GO) is a promising method for rapid and scalable production of graphene. However, homogeneous incorporation of thus prepared graphene into polymer matrix is still a hard task. In this article, we present a ball‐milling assisted wet compounding method for the fabrications of microwave‐reduced GO (MRGO)/polymer composites. MRGO powders were added into a solution of polystyrene (PS) and then mechanically exfoliated in a stirring mill. Scanning electron microscopy and transmission electron microscopy investigations show that the graphene sheets have been homogeneously dispersed in the PS matrix. The composites show pronouncedly improved properties. The thermal degradation temperature of composites increased by 34°C with the addition of 5wt% MRGO in PS. Up to 76% improvement of storage modulus (at 30°C) is achieved by compounding with 10wt% MRGO.POLYM. COMPOS., 2013. © 2013 Society of Plastics Engineers

Hierarchical 3D Nanocomposites towards Advanced Electrochemical Energy Storage

ABSTRACTPolyaniline nanofibers (PANI-NFs)/graphite oxide (GO) nanocomposites with excellent interfacial interaction and elongated fiber structures were synthesized via a facile interfacial polymerization method. This method efficiently exfoliated the expanded layer structure of GO into individual sheet and thus significantly enhanced the specific surface area. The reduced diameter of PANI-NFs in PANI-NF/GO than that of pure PANI-NFs could shorten the diffusion distance and enhance the electro-active sites. The PANI-NFs/GO hybrid materials showed orders of magnitude enhancement in capacitance and better cycling stability than that of individual GO and PANI-NF components.

Synthesis of hydroxyapatite-reduced graphite oxide nanocomposites for biomedical applications: oriented nucleation and epitaxial growth of hydroxyapatite.

Regardless of its successful clinical applications, load-bearing implant applications of hydroxyapatite (HA) remain problematic due to its intrinsic property limitations. Recent findings of the promising biocompatibility of graphene imply the possibilities of it being potentially used as additives for HA-based composites with enhanced mechanical properties. Here we report HA-reduced graphite oxide nanocomposites synthesized by a liquid precipitation approach followed by spark plasma sintering consolidation. The reduced graphite oxide (rGO) consisted of 2-6 layers of graphene. Rod-like HA grains with the dimensions of ∼9 nm in diameter and 20-45 nm in length exhibited oriented nucleation and epitaxial growth on graphene flakes. The (300) plane of HA crystals formed a coherent interfacial bond with the graphene wall and the section of the graphene sheet built a strong interface with the (002) plane of HA crystals. These structural features gave rise to enhanced densification and precluded grain growth of HA in the spark plasma sintered pellets. Fracture toughness of the HA-rGO composites reached 3.94 MPa m1/2, showing a 203% increase compared to pure HA. Crack deflection, crack tip shielding and crack bridging at the HA-rGO interfaces were disclosed as the major strengthening regimes in the composites. The enhanced mechanical properties together with the improved proliferation and ALP activity of the human osteoblast cells suggest a great potential of the composites for biomedical applications.

Electrical and Thermal Properties of Poly(p-phenylene sulfide) Reduced Graphite Oxide Nanocomposites

Graphite oxide (GO) was produced using the modified Hummer's method. Poly(p-phenylene sulfide) (PPS)/reduced graphite oxide (RGO) composites were prepared by in situ polymerization method. The electrical conductivity of the PPS/RGO composites was no more than 82 S/m. It was found that as GO content increased in the PPS/RGO composites, the crystallization temperature and electrical conductivity of the composites increased and the percolation threshold value was at 5-8 wt% of GO content.

Interfacial polymerized polyaniline/graphite oxide nanocomposites toward electrochemical energy storage

Polyaniline nanofibers (PANI-NFs)/graphite oxide (GO) nanocomposites with excellent interfacial interaction and elongated fiber structure were synthesized via a facile interfacial polymerization method. This polymerization method efficiently exfoliated the expanded layer structure of GO into individual sheets and thus significantly enhanced the specific surface area. Direct evidence of a strong interaction between PANI-NFs and GO was observed from TEM results. The reduced diameter of PANI-NFs in PANI-NF/GO than that of pure PANI-NFs could shorten the diffusion distance and enhance the electro-active sites. The PANI-NFs/GO hybrid materials showed orders of magnitude enhancement in capacitance and energy density than that of individual GO and PANI-NF components. The higher PANI-NFs fraction in composites generated an energy density of 7.1 W h/kg at a power density of 80 W/kg. The enlarged electrochemical capacitance of the PANI-NFs/GO nanocomposites was attributed to the increased specific surface area, which improved the accessibility of ions from electrodes to electroactive materials as well as the improved conductivity due to the excellent interfacial interaction. PANI nanoparticles were observed in the nanocomposites when surface initiated polymerization method was used to prepare the polymer nanocomposites. At the same weight loading of PANI in the composites, fibrous PANI demonstrated higher energy density and long term stability than that of particle-shaped PANI at higher power density.

Microstructural and microwave shielding characteristics of water‐soluble polypyrrole–polyvinyl alcohol–graphite oxide core–shell nanocomposites

AbstractThis article reports on a facile route for the preparation of polypyrrole–polyvinyl alcohol–graphite oxide nanocomposites through the polymerization of pyrrole with different concentration (wt%) of graphite oxide using ammonium persulfate as an oxidant. The synthesized nanocomposites were characterized by Fourier transform infrared spectroscopy, and their surface morphologies were studied by scanning electron microscopy and transmission electron microscopy. Their solubility in water, DC conductivity in solution, and the current–voltage characteristics of the nanocomposites were studied. Furthermore, the microwave absorption at 1.0–10.0 MHz and the effects of sample thickness on the microwave absorption were investigated. The composites including higher concentration of graphite oxide showed increased solubility and electrical conductivity, and high electromagnetic shielding effectiveness. POLYM. COMPOS. 2012. © 2012 Society of Plastics Engineers

Retracted: PP/PP‐g‐MAH/layered expanded graphite oxide nanocomposites prepared via masterbatch process

Journal of Applied Polymer ScienceVolume 128, Issue 1 p. 600-610 Article Retracted: PP/PP-g-MAH/layered expanded graphite oxide nanocomposites prepared via masterbatch process Retraction(s) for this article PP/PP-g-MAH/layered expanded graphite oxide nanocomposites prepared via masterbatch process Jun Bian, Xiao Wei Wei, Hai Lan Lin, I Ta Chang, Erol Sancaktar, Volume 130Issue 4Journal of Applied Polymer Science pages: 3025-3025 First Published online: June 13, 2013 Jun Bian, Jun Bian Key Laboratory of Special Materials and Preparation Technologies, College of Materials Science and Engineering, Xi-hua University, Chengdu, Sichuan 610039, People's Republic of ChinaSearch for more papers by this authorXiao Wei Wei, Xiao Wei Wei Key Laboratory of Special Materials and Preparation Technologies, College of Materials Science and Engineering, Xi-hua University, Chengdu, Sichuan 610039, People's Republic of ChinaSearch for more papers by this authorHai Lan Lin, Hai Lan Lin Key Laboratory of Special Materials and Preparation Technologies, College of Materials Science and Engineering, Xi-hua University, Chengdu, Sichuan 610039, People's Republic of ChinaSearch for more papers by this authorI Ta Chang, I Ta Chang Department of Polymer Science and Engineering, Polymer Engineering Academic Center, University of Akron, Akron, Ohio 44325-0301Search for more papers by this authorErol Sancaktar, Erol Sancaktar Department of Polymer Science and Engineering, Polymer Engineering Academic Center, University of Akron, Akron, Ohio 44325-0301Search for more papers by this author Jun Bian, Jun Bian Key Laboratory of Special Materials and Preparation Technologies, College of Materials Science and Engineering, Xi-hua University, Chengdu, Sichuan 610039, People's Republic of ChinaSearch for more papers by this authorXiao Wei Wei, Xiao Wei Wei Key Laboratory of Special Materials and Preparation Technologies, College of Materials Science and Engineering, Xi-hua University, Chengdu, Sichuan 610039, People's Republic of ChinaSearch for more papers by this authorHai Lan Lin, Hai Lan Lin Key Laboratory of Special Materials and Preparation Technologies, College of Materials Science and Engineering, Xi-hua University, Chengdu, Sichuan 610039, People's Republic of ChinaSearch for more papers by this authorI Ta Chang, I Ta Chang Department of Polymer Science and Engineering, Polymer Engineering Academic Center, University of Akron, Akron, Ohio 44325-0301Search for more papers by this authorErol Sancaktar, Erol Sancaktar Department of Polymer Science and Engineering, Polymer Engineering Academic Center, University of Akron, Akron, Ohio 44325-0301Search for more papers by this author First published: 10 July 2012 https://doi.org/10.1002/app.38243Citations: 6AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Citing Literature Volume128, Issue15 April 2013Pages 600-610 RelatedInformation

Controllable synthesis of titania/reduced graphite oxide nanocomposites with various titania phase compositions and their photocatalytic performance

A facile method is presented for preparing TiO2/reduced graphite oxide (RGO) nanocomposites with phase-controlled TiO2 nanoparticles via redox reaction between the reductive titanium (III) precursor and graphite oxide (GO), and a series of TiO2/RGO composites with various TiO2 phase compositions were obtained. In all the titania/RGO composites, the TiO2 nanoparticles were uniformly distributed on the surface of the RGO. The TiO2 consisted of anatase phase particles in the form of square-plates with edges less than 10 nm and the rutile phase nanorods in diameters less than 10 nm. The performances of the as-prepared TiO2/RGO composites were investigated on catalytically degrading phenol under visible light irradiation. The TiO2/RGO composites can effectively degrade phenol under visible light irradiation, and the phase composition of TiO2 in the composites significantly influences the activities of these catalysts.

Pt/titania/reduced graphite oxide nanocomposite: An efficient catalyst for nitrobenzene hydrogenation

In this work, a ternary composite, Pt/TiO2/RGO (reduced graphite oxide), was prepared via immobilizing Pt particles onto the TiO2/RGO composite that was obtained via redox reaction of TiCl3 and GO. The composite was characterized by different techniques including X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy. The TiO2 particles with size less than 10nm were uniformly distributed throughout the RGO, and almost each Pt particle with size around 3nm adhered to TiO2 particles, resulting in high dispersion of all Pt particles on the support. The Pt particles were in the electron-deficient state due to the strong interactions with the TiO2 particles and the RGO support. The catalytic performance of the composite for nitrobenzene hydrogenation was investigated under solvent-free condition. It was indicated that the Pt/TiO2/RGO catalyst exhibited high activity with a turnover frequency (e.g., 59,000h−1) as well as superior selectivity to aniline (e.g., >99%). Moreover, the catalyst can be reused for six times without any activity loss, which resulted from the stable structure of the catalyst.

Crystallization Properties of Polypropene/Graphene Oxide Nanocomposites

Polypropene (PP)/graphite oxide (GO) nanocomposite was prepared via solution blending and studied by adopting polarized optical microscopy observations, X-ray diffraction analysis and differential scanning calorimetry analysis. It is found that GO acts as an effective heterogeneous nucleation agent. The addition of GO doesn’t change the crystalline structure of PP, but leads to the decrease of spherulite dimension. GO makes the temperature of the crystallization exothermic peak increase, the crystallization temperature range and the half width of the crystallization peak narrow.

Reduced Graphite Oxide Nanocomposites for Electrochemical Capacitor Applications

not Available.

Synthesis and characterization of polyamide-6/graphite oxide nanocomposites

Polyamide-6/graphite oxide (PA6/GO) nanocomposites were synthesized using delamination/absorption method. The morphologies of the composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). Both XRD and TEM showed that the GO sheets were completely exfoliated and distributed uniformly in PA6 matrix. Differential scanning calorimetry results revealed that the crystallization temperatures of the composites increased compared to that of pristine PA6, which was due to the heterogeneous nucleating effect of GO. However, the half-time of crystallization of the composites were evidently longer than that of pristine PA6, indicating an apparent decrease in the crystallization rate when GO was loaded into the polymer matrix. This was due to the constraining effect of layered GO on PA6 chains. The temperature of maximum decomposition rate was increased by 53 °C only by adding 5 wt% GO, and the maximum decomposition rate of the nanocomposites reduced greatly. The storage modulus (G′) and loss modulus (G″) curves shifted to higher modulus upon addition of 1–5 wt% of GO. With increasing GO loading, the shear viscosity of the nanocomposites gradually increased compared with pure PA6.

Synthesis of a Graphite Oxide Polyaniline Nano‐Composite by an Electrochemical Method

AbstractIn order to produce a polyaniline graphite oxide nano‐composite, electro‐polymerization of aniline was performed within the graphite oxide layers via electrochemical treatment of aniline‐intercalated graphite oxide in the supporting electrolyte. It was found that graphite oxide has special electro‐active properties. Therefore, electrochemical polymerization of aniline was performed on a Pt substrate in the presence of graphite oxide that had been dispersed in the electrolyte solution by the cyclic voltammetric method. Formation of polyaniline within the layers of graphite oxide occurred during electro‐polymerization. This mechanism affects the polyaniline morphology and leads to the formation of well‐defined concrete microstructures differing from the pure graphite oxide. Moreover, the results of the thermogravimetric analysis showed that graphite oxide and the polyaniline graphite oxide nano‐composite electrodeposited on the Pt substrate have different weight loss behaviors. This confirms that intercalation of the polyaniline improved the oxidation stability of graphite oxide, along with the fact that the polyaniline graphite oxide nano‐composite was successfully synthesized by an electrochemical method.

Non-isothermal crystallization kinetics of polyamide-6/graphite oxide nanocomposites

Polyamide-6 (PA6)/graphite oxide (GO) nanocomposite was synthesized using delamination/absorption with dimethylacetamide as solvent. TEM showed that graphite oxide sheets were completely exfoliated and distributed uniformly in polyamide-6 matrix. Non-isothermal crystallization behaviors of PA6 and nanocomposites were investigated using DSC. The modified Avrami, Mo and Ozawa equation were employed to investigate the crystallization process. The former two could successfully describe the non-isothermal crystallization of PA6 and nanocomposites. It was interesting to find that Ozawa equation could successfully describe the non-isothermal crystallization of nanocomposites, but it was not valid for PA6. The crystallization rate of nanocomposites greatly decreased by the addition of GO, which confirmed by the results of half-time of crystallization ( t 1/2), crystallization rate exponent Z c and log F( T). Also, the more the content of GO, the slower the crystallization rate. The effective activation energy calculated from Friedman formula suggested that the layered structure of GO restrained the crystallization of PA6.

Characterization and electrical properties of conductive polymer/colloidal graphite oxide nanocomposites

Conductive polymers such as polypyrrole (PPy) and poly(3,4-ethylenedioxythiophene) (PEDOT) have been synthesized in the presence of colloidal graphite oxide (CGO) prepared via Hummers and Offerman’s method, thus obtaining PPy/CGO and PEDOT/CGO nanocomposites. The resulted nanocomposites provide high and adjustable electrical conductivity when doped with different dopants, and a much better thermal stability than pristine CGO. For the case of doped PPy/CGO nanocomposites, CGO is confirmed experimentally to be exfoliated and thus could offer more “active sites” for the polymerization of pyrrole. For the case of doped PEDOT/CGO nanocomposites, X-ray diffraction analyses indicate the formation of PEDOT with the aid of CGO in aqueous media in spite of its monomeric water insolubility and a possible part intercalation of PEDOT between the layers of CGO. The temperature dependence of conductivity supports the three-dimensional Mott’s variable range hopping mechanism for doped PPy/CGO and PEDOT/CGO nanocomposites. The Fourier-transform infrared (FTIR) spectroscopy and electron spin resonance (ESR) spectra data, as evidence verifies that the charge carriers in doped PPy/CGO nanocomposites are polarons, while bipolarons serve as charge carriers in doped PEDOT/CGO nanocomposites.