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1.
In this study, nanosheets including graphene oxide (GO) and reduced graphene oxide (rGO), were incorporated into natural rubber (NR), to study the effects of substituting GO or rGO for carbon black (CB) on the structure and performance of NR/CB composites. The morphological observations revealed the dispersion of CB was improved by partially substituting nanosheets for CB. The improvements in static and dynamic mechanical properties were achieved at small substitution content of GO or rGO nanosheets. With substitution of rGO nanosheets, significant improvement in flex cracking resistance was achieved. NR/CB/rGO (NRG) composites has a much lower heat build‐up value compared with NR/CB/GO (NG) composites at a high load of nanosheets. However, both GO and rGO tended to aggregate at a high concentration, which led to the poor efficiency on enhancing the dynamic properties, or even deteriorate the performance of rubber composites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41832.  相似文献   

2.
Currently, there is great interest in graphene‐based devices and applications because graphene has unique electronic and material properties, which can lead to enhanced material performance. Graphene may be used in a wide variety of potential applications from next‐generation transistors to lightweight and high‐strength polymeric composite materials. Graphene, which has atomic thickness and two‐dimensional sizes in the tens of micrometer range or larger, has also been considered a promising nanomaterial in gas‐ or liquid‐barrier applications because perfect graphene sheets do not allow diffusion of small gases or liquids through its plane. Recent molecular simulations and experiments have demonstrated that graphene and its derivatives can be used for barrier applications. In general, graphene and its derivatives can be applied via two major routes for barrier polymer applications. One is the transfer or coating of few‐layered, ultrathin graphene and its derivatives, such as graphene oxide (GO) and reduced graphene oxide (rGO), on polymeric substrates. The other is the incorporation of fully exfoliated GO or rGO nanosheets into the polymeric matrix. In this article, we review the state‐of‐the‐art research on the use of graphene, GO, and rGO for barrier applications, including few‐layered graphene or its derivatives in coated polymeric films and polymer nanocomposites consisting of chemically exfoliated GO and rGO nanosheets, and their gas‐barrier properties. As compared to other nanomaterials being used for barrier applications, the advantages and current limitations are discussed to highlight challenging issues for future research and the potential applications of graphene/polymer, GO/polymer, and rGO/polymer composites. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39628.  相似文献   

3.
A functionalized graphene, fluorinated graphene nanosheets (FGS), and SiO2 nanoparticles as reinforcing fillers were employed to improve the mechanical properties of the solution styrene butadiene and butadiene rubber composites (SSBR‐BR). The results showed that the mechanical properties of SSBR‐BR composite filled with FGS were substantially improved than those of the unfilled and equivalent filler loaded graphene oxide (GO) and reduced graphene oxide (rGO) filled SSBR‐BR composites. It can be ascribed to the fact that the hydrophobic surface of FGS can be endowed the good dispersion in rubber matrix and stronger interfacial interaction between rubber and fillers. The tribological properties of these composites are also investigated. The results reveal that incorporation of GO, rGO, and FGS in SSBR‐BR composites can decrease antiwear properties because the existence of layered graphene promotes to tear and peel off. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44970.  相似文献   

4.
In this study, graphite oxide (GO) is synthesized from natural graphite flakes by the modified Hummers method. Characterization by Fourier transform infrared, X‐ray photoelectron, Raman and ultraviolet‐visible spectroscopies, X‐ray diffraction, and thermogravimetric analysis is conducted on GO to confirm the oxidation of graphite. Unplasticized and glycerol plasticized chitosan/graphene oxide (CS/GO) nanosheets nanocomposites with different GO loadings are prepared by solution casting. The combined effect of GO and glycerol on structure, thermal and mechanical properties of nanocomposite films is studied. GO nanosheets are well dispersed throughout the CS matrix due to the hydrogen bonding and electrostatic interactions between CS and GO nanosheets. The incorporation of GO within the CS matrix results in a decrease of the crystallinity, an improvement of thermal stability, and a significant enhancement of the stiffness and tensile strength that is emphasized by the glycerol. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45092.  相似文献   

5.
Pyrrole monomer was polymerized by a chemical oxidative route in the presence of graphene oxide (GO), reduced GO (rGO), and graphene nanoribbons (GNR) separately to prepare composites of polypyrrole (PPy) as PPy–GO, PPy–rGO, and PPy–GNR, respectively. The morphological, chemical, and structural characterization of the as‐synthesized products was carried out using scanning electron microscopy, Raman spectroscopy, and Fourier transform infrared spectroscopy. Field emission studies of the PPy–GO, PPy–rGO, and PPy–GNR emitters were performed at the base pressure of 1 × 10?8 mbar in a planar “diode” configuration. The turn‐on field values, corresponding to an emission current density of 1 µA/cm2, are observed to be 1.5, 2.2, and 0.9 V/µm for the PPy–GO, PPy–rGO, and PPy–GNR emitters, respectively. The maximum emission current density of 2.5 mA/cm2 is drawn from PPy–GO at an applied electric field of 3.2 V/µm, 1.2 mA/cm2 at 3.6 V/µm from the PPy–rGO, and 8 mA/cm2 at 2.2 V/µm from the PPy–GNR emitters. All of the composites exhibit good emission stability over more than 2 h. The results indicate the potential for a facile route for synthesizing composites of conducting polymers and graphene‐based materials, with enhanced functionality. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45170.  相似文献   

6.
An in situ strategy for fabrication of reduced graphene oxide/fused silica (rGO/FS) composites using 3-aminopropyltriethoxysilane as surfactant is reported. GO nanosheets were bound to FS particles by an electrostatic assembly between ultra thin negatively charged GO sheets and positively charged amino-modified FS particles. After spark plasma sintering, rGO/FS bulk composites have been produced from the GO and FS composite particles with GO being reduced to rGO in vacuum at high temperatures. Results show that rGO sheets were well dispersed in the matrix, and conductivity of these rGO/FS composites at room temperature was strongly dependent on the rGO nanosheet concentration. i.e., the conductivity of rGO/FS was increased to 10−4 S/cm when a conducting network was formed inside the composites. The effect of GO nanosheets on the mechanical properties of rGO/FS bulk composites was also investigated. The addition of 1 wt.% GO sheets to FS resulted in 72% increase in Vickers hardness, indicating the stress transfering from the FS matrix to the rigid rGO sheets. With the same rGO content, the fracture toughness of the as-prepared composites was increased by 74%. The main toughening mechanisms were thought to be crack deflection, crack branching, pulling-out and bridging of the rGO sheets.  相似文献   

7.
Laponite or graphene oxide (GO) is usually used as a multifunctional crosslinker or a nanofiller to improve the nanocomposite gel strength. To explore the strengthening mechanism of GO/Laponite‐based dual nanocomposite hydrogels, we synthesized a dual nanocomposite hydrogel through in situ polymerization of acrylamide (AM) in the dispersion of GO and Laponite. The interactions between GO and Laponite were confirmed by rheological test. GO and Laponite nanosheets were exfoliated well and dispersed uniformly in the hydrogels at low concentration of GO. Crosslinking network and thermal behaviors were investigated with respect to the concentration of GO and Laponite. The gel exhibited a high mechanical strength of 391 kPa with extensibility of 1420% and a high toughness of 2.58 MJ/m3, which was expected to be applied in biological engineering field. GO is not a much more effective agent than Laponite due to formation of GO aggregates in high concentration of GO. This work provides a guidance for the synthesis of tough dual nanocomposite hydrogels. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44963.  相似文献   

8.
We report a novel, green, scalable technique to synthesize binder-free, high-purity conductive composite comprising activated carbon (AC), manganese dioxide nanorods (MnO2), and reduced graphene oxide sheets (rGO) for flexible supercapacitors with outstanding electrochemical performance. UV pulsed laser irradiation of GO-based composite dispersion (AC/GO or MnO2@AC/GO) in ethanol aqueous medium was used to induce a photocatalytic reduction of GO and simultaneous anchor AC particles or AC loaded MnO2 nanorods (MnO2@AC) on the reduced GO sheets (rGO) at room temperature and atmospheric pressure. rGO sheets serve as a large surface area, conductive binder to enhance the ion adsorption, electrical conductivity, and mechanical flexibility of supercapacitor electrodes. This laser-induced photocatalytic reduction method was used to prepare two different rGO-based colloidal composites AC/rGO (CG) and MnO2@AC/rGO (MCG). The prepared rGO-based colloidal composites were used to fabricate symmetric supercapacitors (CG//CG and MCG//MCG) and asymmetric supercapacitors (MCG//CG) in which MCG is the positive electrode and CG is the negative one. All prepared rGO-based supercapacitors demonstrated significant improvement in their electrochemical performance compared with rGO-free AC based supercapacitors. The enhancement in the electrochemical properties of rGO-based supercapacitors could be attributed to the intrinsic characteristics of rGO, such as high surface area, excellent electrical conductivity, and super mechanical flexibility. Our approach is a one-step, scalable, cost-effective synthesis technique to produce all binder-free AC/rGO based composites for flexible energy-storage devices.  相似文献   

9.
In this work, cationized cotton/nylon fabric was treated with reduced graphene oxide (rGO) to produce highly conductive fabric. The fabric was cationized with 3‐chloro‐2‐hydroxy propyl trimethyl ammonium chloride to attract more anionic GO. The fabric was then treated with GO followed by reduction with sodium dithionite. The results of energy‐dispersive X‐ray spectroscopy, X‐ray diffraction, and X‐ray photoelectron spectroscopy indicated entire coverage of the fabric surface with rGO. The color of fabrics changed to gray‐black and the electrical resistance decreased to 0.6 × 103 Ω sq?1. The washing fastness was measured according to ISO 105‐CO5 for color change and also electrical resistance of the samples demonstrated well stability of rGO on the fabric surface. The antibacterial activities of the treated fabrics improved against Gram‐negative bacteria including Escherichia coli (84.8%) and Pseudomonas aeruginosa (96.4%) and also Gram‐positive bacteria consisting Staphylococcus aureus (100%) and Enterococcus faecalis (98.4%). Further, the treated fabrics indicated an excellent UV reflectance of 100%. Finally heating of the cationized rGO fabric at 220 °C displayed a lower electrical resistance of 0.5 × 103 Ω sq?1. The thermogravimetric analysis showed that heating has a slight effect on the dimensional thermal stability of the treated fabric as shrunk 2.43%. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45493.  相似文献   

10.
High thermal conductivity of nanocomposite-based polymer matrix is one of the most important keys in developing many heat exchanger instruments. Here, we report a novel nanocomposite system based on silver-coated reduced graphene oxide (Ag/rGO) in silane cross-linked low-density polyethylene (XLPE) matrix with unprecedented through-plane thermal conductivity. Compared to the virgin rGO, Ag/rGO nanocomposite showed 67% higher thermal conductivity due to the Ag nanoparticles (NPs) decoration. The Ag NPs within the nanocomposites are believed to act as a thermal conductor among rGO nanosheets and eventually enhance the heat conduction in 3D manner.  相似文献   

11.
To construct rapid C3H8 transport pathways in polymer matrix, alkyl chain‐functionalized graphene oxide (GO) was prepared via grafting octadecylamine (ODA) molecules and then embedded into polydimethylsiloxane (PDMS) matrix to obtain high‐efficiency mixed matrix membranes (MMMs). The incorporation of alkyl chains contributes to lowering the surface energy of GO nanosheets and providing higher affinity with PDMS matrix. Additionally, the alkyl chains on the surface of ODA‐functionalized GO nanosheets (ODA‐GO) are in favor of C3H8 adsorption, thus conferring continuous and specific transport pathways for C3H8. The optimized membrane with ODA‐GO loading of 0.3 wt% exhibits the C3H8 permeance of 1897 GPU and the C3H8/N2 ideal selectivity of 67, which are 50.2 and 72.5% higher than those of bare PDMS membrane, respectively. The simultaneous enhancement of C3H8 permeance and C3H8/N2 ideal selectivity indicates that ODA‐GO is an effective filler applied in MMMs for C3H8 recovery. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3501–3510, 2017  相似文献   

12.
The reduced graphene oxide–gold nanoparticle (rGO–Au NP) membranes are prepared by vacuum filtration method. The sizes of the Au NPs on the surface of the rGO are about 8–10 nm, and the lattice spacing of Au NPs is 0.0241 nm, which is relative to the cubic lattice of the gold crystal. The layer-by-layer stacking structure of rGO–Au NP membrane can be observed clearly by field emission scanning electron microscopy. The water flux of the rGO–Au NP membrane is as high as 204.1 L m?2 h?1 bar?1, and its retention for Rhodamine B (RhB) is as high as 99.79%.  相似文献   

13.
Two different types of graphene‐based composites have been synthesized with simple assays. The multifunctional composites were obtained through loading Fe3O4@phenol formaldehyde resin (PFR) nanoparticles (NPs) synthesized with Fe3O4 NPs, hexamethylene‐tetramine, and phenol onto the surface of graphene oxide sheets in the presence of coupling agent. The Fe3O4@PFR loaded graphene oxide composites bring several merits. It prevents PFR NPs aggregation due to the existed graphene oxide but also endows the composites photothermal conversion property. Furthermore, the graphene‐wrapped PFR composites were prepared by mixing oxide graphene and PFR NPs at 110 °C by means of the good reduction of the hydroxyl group on the surface of PFR NPs to graphene. Under the assistance of chitosan, a building block consists of graphene‐wrapped PFR composites could be obtained. Thus, an ideal method may be developed to synthesize graphene‐wrapped PFR composites for constructing building blocks. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45007.  相似文献   

14.
We present a facile one-step electrochemical approach to generate MnO2/rGO nanocomposite from a mixture of Mn3O4 and graphene oxide (GO). The electrochemical conversion of Mn3O4 into MnO2 through potential cycling is expedited in the presence of GO while the GO is reduced into reduced graphene oxide (rGO). The MnO2 nanoparticles are evenly distributed on the rGO nanosheets and act as the spacer to prevent rGO nanosheets from restacking. This unique structure provides high electroactive surface area (1173?m2 g?1) that improves ions diffusion within the MnO2/rGO structure. As a result, the MnO2/rGO nanocomposite exhibits high specific capacitance of 473?F?g?1 at 0.25?A?g?1, which is remarkably higher (3 times) than the Mn3O4/GO prior conversion. In addition, the electrosynthesized nanocomposite shows higher conductivity and excellent potential cycling stability of 95% at 2000 cycles.  相似文献   

15.
The delicacy and connectivity of conductive patterns developed via poly[benzodithiophene‐bis(decyltetradecylthien)naphthothiadiazole] (PBDT‐DTNT) and poly[bis(triisopropylsilylethynyl)benzodithiophene‐bis(decyltetradecylthien)naphthobisthiadiazole] (PBDT‐TIPS‐DTNT‐DT) polymers were investigated on reduced graphene oxide (rGO) nanosheets. The principal driving force for assembly of PBDT‐DTNT and PBDT‐TIPS‐DTNT‐DT chains onto the rGO nanosheets was π‐stacking. In contrast to poly(3‐hexylthiophene) (P3HT), the surface modification of rGO limited the self‐assembly of PBDT‐DTNT and PBDT‐TIPS‐DTNT‐DT complicated polymers. The structure of PBDT‐DTNT and PBDT‐TIPS‐DTNT‐DT chains having fused and infused thiophenic and benzenic rings hindered their molecular ordering compared to P3HT, and therefore the selected area electron diffraction plots demonstrated rings instead of isolated growth planes. Although 2‐thiophene acetic acid (TAA) functional groups and poly(3‐dodecylthiophene) (PDDT) grafted onto rGO nanosheets did not alter the stacking type of the complicated polymers, it made their attachment more difficult. The thickness of π‐stacked patterns ranged from 55 to 70 nm. In the modified areas of rGO, the PBDT‐DTNT and PBDT‐TIPS‐DTNT‐DT chains were not capable of being deposited with a π‐interaction. Hence, the surface modification agents prevented the complicated polymers from interconnectedly assembling and, consequently, constructing longer and larger patterns. This hindrance was more noticeable for the supramolecules based on grafted rGO (rGO‐g‐PDDT) and PBDT‐TIPS‐DTNT‐DT. The conductivity of PBDT‐DTNT/rGO superstructures was the highest (14.61–14.89 S cm?1). The patterned nanohybrids could be considered as potential super‐materials for morphology‐templating in the active layers of organic–inorganic photovoltaics. © 2018 Society of Chemical Industry  相似文献   

16.
Intercalated laminar membrane with controllable interlayer spacing (d-spacing) is one of the most effective membranes for fast molecule separation. In this work, we demonstrate a versatile strategy to create nanosheet-templated water channels in laminar graphene oxide (GO) membranes. The 1.2 nm-thick nickel hydroxide nanosheets as sacrificed intercalators provide a chance to control the d-spacing. The resultant membranes have controllable channels and exhibit over six times higher water permeance than the unintercalated membrane. The 880 nm-thick nanosheet-templated GO (NST-GO) membrane has accurate d-spacing of about 1.14 nm and shows high water permeance of 120.3 L m−2 h−1 bar−1 and good molecule separation property, reflecting in high rejection for larger dyes (90.1% for erythrosine B [EB]), while low rejection for smaller dyes (58.3% for methylene blue [MB]). Furthermore, this strategy of intercalating and sacrificing nanosheets has higher potential than traditional intercalation in controlling d-spacing of laminar membranes.  相似文献   

17.
There is a need for developing reliable models for water and solute transport in graphene oxide (GO) membranes for advancing their emerging industrial water processing applications. In this direction, we develop predictive transport models for GO and reduced-GO (rGO) membranes over a wide solute concentration range (0.01–0.5 M) and compositions, based on the extended Nernst–Planck transport equations, Donnan equilibrium condition, and solute adsorption models. Some model parameters are obtained by fitting experimental permeation data for water and unary (single-component) aqueous solutions. The model is validated by predicting experimental permeation behavior in binary solutions, which display very different characteristics. Sensitivity analysis of salt rejections as a function of membrane design parameters (pore size and membrane charge density) allows us to infer design targets to achieve high salt rejections. Such models will be useful in accelerating structure-separation property relationships of GO membranes and for separation process design and optimization.  相似文献   

18.
Homogeneous dispersion and strong filler–matrix interfacial interactions were vital factors for graphene for enhancing the properties of polymer composites. To improve the dispersion of graphene in the polymer matrix and enhance the interfacial interactions, graphene oxide (GO), as an important precursor of graphene, was functionalized with amine‐terminated poly(ethylene glycol) (PEG–NH2) to prepare GO–poly(ethylene glycol) (PEG). Then, GO–PEG was further reduced to prepare modified reduced graphene oxide (rGO)–PEG with N2H4·H2O. The success of the modification was confirmed by Fourier transform infrared spectroscopy, thermogravimetric analysis, and Raman spectroscopy. Different loadings of rGO–PEG were introduced into polyimide (PI) to produce composites via in situ polymerization and a thermal reduction process. The modification of PEG–NH2 on the surface of rGO inhibited its reaggregation and improved the filler–matrix interfacial interactions. The properties of the composites were enhanced by the incorporation of rGO–PEG. With the addition of 1.0 wt % rGO–PEG, the tensile strength of PI increased by 81.5%, and the electrical conductivity increased by eight orders of magnitude. This significant improvement was attributed to the homogeneous dispersion of rGO–PEG and its strong filler–matrix interfacial interactions. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45119.  相似文献   

19.
The graphene oxide (GO) was prepared by sonication‐induced exfoliation from graphite oxide, which was produced by oxidation from graphite flakes with a modified Hummer's method. The GO was then treated by hydrazine to obtain reduced graphene oxide (rGO). On the basis of the characterization results, the GO was successfully reduced to rGO. Acrylonitrile–butadiene rubber (NBR)–GO and NBR–rGO composites were prepared via a solution‐mixing method, and their various physical properties were investigated. The NBR–rGO nanocomposite demonstrated a higher curing efficiency and a change in torque compared to the gum and NBR–GO compounds. This agreed well with the crosslinking density measured by swelling. The results manifested in the high hardness (Shore A) and high tensile modulus of the NBR–rGO compounds. For instance, the tensile modulus at a 0.1‐phr rGO loading greatly increased above 83, 114, and 116% at strain levels of 50, 100, and 200%, respectively, compared to the 0.1‐phr GO loaded sample. The observed enhancement was highly attributed to a homogeneous dispersion of rGO within the NBR matrix; this was confirmed by scanning electron microscopy and transmission electron microscopy analysis. However, in view of the high ultimate tensile strength, the NBR–GO compounds exhibited an advantage; this was presumably due to strong hydrogen bonding or polar–polar interactions between the NBR and GO sheets. This interfacial interaction between GO and NBR was supported by the marginal increase in the glass‐transition temperatures of the NBR compounds containing fillers. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42457.  相似文献   

20.
How to preserve the structure integrity of graphene while enhance its dispersion and compatibility in matrix attracts the attention of researchers in graphene/polymer nanocomposite field. In this paper, methacryloxyethyltrimethyl ammonium chloride (DMC), a kind of ionic liquids, was first used to non‐covalently functionalize graphene in the process of graphene oxide (GO) reduction. The as‐modified graphene (DMC‐rGO) was further incorporated into poly(vinyl alcohol) (PVA) matrix by solution casting technique to fabricate DMC‐rGO/PVA composites. The structure and properties of the obtained DMC‐rGO were investigated by X‐ray diffraction analysis (XRD), X‐ray Photoelectron Spectroscopy (XPS), Transmission Electron Microscope (TEM), Atomic force microscopy (AFM), and Raman test. The results showed that graphene could be successfully modified by DMC through ionic–π interaction and the structure integrity of the graphene could be reserved by this non‐covalently approach. Furthermore, after co‐reduction process, some hydroxyl groups were introduced into DMC‐rGO. In virtue of these intrinsic properties of DMC‐rGO, the fabricated DMC‐rGO/PVA composites exhibit considerable enhancements in mechanical properties and remarkable improvements in thermal stability, as well as the enhancement in electrical conductivity at low DMC‐rGO loading. This simple modification approach gives a new opportunity to improve the performances of graphene/polymer composites. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45006.  相似文献   

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