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1.
The goal of this research was to simplify the preparation process of graphene-contained powder coatings for metal anticorrosion. To do this, thermosetting powder/graphene oxide (TP@GO) composites were prepared via a facile planetary ball-milling technique and were painted onto tinplates by electrostatic spraying. After immersion in a 3.5 wt % NaCl solution for 9 days, potentiodynamic polarization curves revealed superior anticorrosion performance for the 1.5 wt % graphene oxide coating (TP@GO15), providing 74.1% decreased corrosion current and 34.2% increased corrosion potential compared to pure thermosetting powder coating. After 48 days of immersion, the electrochemical impedance spectroscopy analysis of the prepared materials revealed that the anticorrosion properties were in the sequence TP < TP@GO10 < TP@GO20 < TP@GO15. The results indicated that addition of moderate amount of graphene oxide to prepare TP@GO coatings can significantly promote the anticorrosion performance of metals. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48264.  相似文献   

2.
Exploring inexpensive and active bifunctional electrocatalysts to produce hydrogen and oxygen from water at all pHs is highly desirable. Herein, we report a facile one-step method to prepare vertically aligned Co doped MoS2 nanosheets with extended interlayer distance on carbon cloth (Co–MoS2@CC) for full hydrolysis in both alkaline and acidic medium. Co–MoS2@CC exhibits long-term durability with overpotentials of 56.6 mV and 130 mV for hydrogen generation and 242 mV and 201 mV for oxygen production at 10 mA cm?2 in basic and acidic conditions, respectively. Moreover, we achieve low voltages of 1.585 V and 1.55 V in basic and acidic conditions respectively for the overall water splitting. We assume that such excellent property of Co–MoS2@CC may be ascribed to the uncovering of more active sites and high porosity resulted from Co doping, which boosts the conductivity and thus reduces MoS2 hydrogen adsorption free energy in HER, as well as benefits to catalytic active sites in OER. This one-step doping approach opens up new ways to regulate the intrinsic catalytic activity to catalyze total hydrolysis at all PHs.  相似文献   

3.
Two-dimensional (2D) MoS2 nanomaterials have been extensively studied due to their special structure and high theoretical capacity, but it is still a huge challenge to improve its cycle stability and achieve superior fast charge and discharge performance. Herein, a facile one-step hydrothermal method is proposed to synthetize an ordered and self-assembled MoS2 nanoflower (MoS2/C NF) with expanded interlayer spacing via embedding a carbon layer into the interlayer. The carbon layer in the MoS2 interlayer can speed the transfer of electrons, while the nanoflower structure promotes the ions transport and improves the structural stability during the charging/discharging process. Therefore, MoS2/C NF electrode exhibits exceptional rate performance (318.2 and 302.3 mA·h·g-1 at 5.0 and 10.0 A·g-1, respectively) and extraordinary cycle durability (98.8% retention after 300 cycles at a current density of 1.0 A·g-1). This work provides a simple and feasible method for constructing high-performance anode composites for sodium ion batteries with excellent cycle durability and fast charge/discharge ability.  相似文献   

4.
In this study, we report UV‐ and thermo‐curable epoxyacrylate/graphene oxide (EA/GO) nanocomposites that present good transparency, excellent pencil hardness and promising improvement in corrosion protection. A dual‐curable EA oligomer with one terminal epoxide and one double bond at the other end was synthesized by reaction of diglycidyl ether of bisphenol‐A and acrylic acid. After mixing EA and GO with the curing agents and reactive diluent followed by UV cure and thermo‐cure, the resulting EA/GO films on a glass slide with GO loading up to 3 phr exhibited over 86% light transmittance. Furthermore, the pencil hardness was enhanced from 3H for EA to 6H for the EA/GO composite at 2 phr GO loading. The corrosion protection of the EA/GO coatings was evaluated by a potentiodynamic polarization technique and electrochemical impedance spectra. The corrosion potential (Ecorr) of the EA/GO‐coated steel increased with increasing GO loading. Meanwhile, Nyquist and Bode plots indicated that the higher the GO content in the EA/GO coating was, the higher was the coating resistance and also the charge transfer resistance after immersion in salt solution. All these results proved that the GO had positive effects on enhancement of the corrosion resistance. The improved corrosion protection by the EA/GO coatings was mainly due to the enhanced hydrophobicity, the deviation of electron transfer and the increased tortuosity of the diffusion path. The improved corrosion protection and hardness together with the useful dual‐curability make the EA/GO nanocomposite a competitive candidate for corrosion protection coatings. © 2019 Society of Chemical Industry  相似文献   

5.
This study developed a scalable and straightforward adaptation methodology for melt processing of polypropylene (PP) to provide a high degree of exfoliation of multilayer graphene oxide (GO) by using a high-shear mixer. GO was first produced by an improved and eco-friendly electrochemical exfoliation by using an environmentally friendly aqueous methanesulfonic acid (MSA) and a sodium sulfate salt system to minimize the environmental impact. The produced GOs then were melt blended with PP and their mechanical, thermal, and morphological properties were investigated under different GO loadings to attain ideal configuration and increase interfacial interactions between polymer matrix and reinforcer. Comparisons were made by producing different PP composites using two different GO types produced in salt and acid environments. Additionally, by applying different voltages to salt system, the effect of applied voltage on the properties of both GO material and the composites were discussed. The characterization results indicated that GO obtained in MSA solution caused a 71% increase in flexural modulus and 46% in flexural strength with the addition of 1 wt% GO. The rheological characterization also showed that dispersion and viscosity improved with lower GO loadings compared to neat polymer by providing cost-effective and scalable graphene manufacturing.  相似文献   

6.
An efficient and improved procedure has been developed for the conversion of oxiranes into thiiranes using sodium thiocyanate in the presence of graphite oxide under solvent-free conditions at an ambient temperature in excellent yields and in short reaction times.  相似文献   

7.
The simultaneous reduction and functionalization of graphene oxide (GO) was realized through a chemical grafting reaction with a functionalization agent N,N-bis(3-aminopropyl)methylamine (APMEL). The reduced and functionalized reduced GO (rGO-APMEL) sheets can be well dispersed in water without any added surfactant and the formed stable rGO aqueous dispersion can be kept for a long time, which can be used for the preparation of rubber–graphene (GE) composites by latex mixing. The electrostatic interaction between rGO–APMEL (positively charged) and natural rubber latex particles (negatively charged) leads to the formation of NR/rGO–APMEL composites with strong interaction. Compared with blank NR, the tensile strength and modulus for NR/rGO–APMEL increase with the rGO–APMEL loading. Especially, when the filler content is 5 phr, the tensile strength of NR/rGO–APMEL-5 increases by 32.7%, as a control the tensile strength of NR/GO-5 and NR/rGO-5 decrease by 20.1 and 15.6%, respectively. The entanglement-bound rubber tube model was used to analyze the reinforcing effect of GE on NR/rGO–APMEL nanocomposites at a molecular level. This study may provide us a novel approach to prepare well dispersed and exfoliated rGO–polymer nanocomposites. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47375.  相似文献   

8.
In this research, hydrogen sulfide is adsorbed on amido-functionalized reduced graphene oxide (AFRGO) as a nanoadsorbent. By the use of n-propylamine and allylamine, reduced graphene oxide (RGO) was amidated for the adsorption of hydrogen sulfide. The materials were characterized by adsorption of H2S, potentiometric titration, scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR) spectroscopy, and X-ray diffraction (XRD) analysis. The effect of the operational conditions of 4000–6000 h?1 space velocities and 60,000?ppm H2S feed concentrations were examined on adsorption capacity. The results show that H2S feed concentration, space velocity, and functional groups of adsorbents have a major effect on H2S adsorption. It was also found that the temperature in the range of 30–70°C had a significant effect on H2S adsorption. The concentration of H2S adsorbed in 3?h by AFRGO containing allyl substituent, AFRGO containing propyl substituent, graphene oxide (GO), and reduced graphene oxide (RGO) were reported as 59,710, 59,650, 59,600, and 59,500?ppm, respectively. Hydrogen sulfide adsorption analysis showed that nanoadsorbents increase adsorption capacity of H2S.  相似文献   

9.
ABSTRACT

In this research, graphene oxide decorated with strontium oxide (SrO/GO) is introduced as a new adsorbent material for the efficient removal of ammonia from industrial wastewater. The new adsorbent was thoroughly studied in terms of morphology, crystallography and chemical composition using characterization techniques such as Fourier transform infrared (FTIR), X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and zeta potential analysis. Several parameters such as pH, adsorbent dosage, contact time, and ammonia initial concentration were investigated and optimized. Ammonia adsorption onto SrO/GO was validated with kinetics and adsorption isotherms by adopting different models. The results revealed that ammonia adsorption kinetic was of pseudo-second order (R2 = 0.999) implying that chemisorption behavior and the equilibrium isotherm follows Langmuir model. This behavior shows a high maximum monolayer sorption capacity of 90.1 mg g?1 at pH equal to 7 and contact time of 120 min pointing out the synergism advantageous effect. The abundant oxygen functional groups on the graphene oxide surface and the integrated Sr-O nanoparticles could efficiently interact with ammonia species creating a surface for more favorable and efficient removal of ammonia.  相似文献   

10.
A nanocomposite of silver nanoparticles/reduced graphene oxide (Ag/rGO) has been fabricated as a surface-enhanced Raman scattering (SERS) substrate owing to the large surface area and two-dimensional nanosheet structure of rGO. A facile and rapid microwave-assisted green route has been used for the formation of Ag nanoparticles and the reduction of graphene oxide simultaneously with L-arginine as the reducing agent. By increasing the cycle number of microwave irradiation from 1 and 4 to 8, the mean diameters of Ag nanoparticles deposited on the surface of rGO increased from 10.3 ± 4.6 and 21.4 ± 10.5 to 41.1 ± 12.6 nm. The SERS performance of Ag/rGO nanocomposite was examined using the common Raman reporter molecule 4-aminothiophenol (4-ATP). It was found that the Raman intensity of 4-ATP could be significantly enhanced by increasing the size and content of silver nanoparticles deposited on rGO. Although the Raman intensities of D-band and G-band of rGO were also enhanced simultaneously by the deposited Ag nanoparticles which limited the further improvement of SERS detection sensitivity, the detectable concentration of 4-ATP with Ag/rGO nanocomposite as the SERS substrate still could be lowered to be 10−10 M and the enhancement factor could be increased to 1.27 × 1010. Furthermore, it was also achievable to lower the relative standard deviation (RSD) values of the Raman intensities to below 5%. This revealed that the Ag/rGO nanocomposite obtained in this work could be used as a SERS substrate with high sensitivity and homogeneity.  相似文献   

11.
A novel graphene oxide‐based fluorhydroxyapatite (GO/FHA) composite is prepared using an in situ chemical synthesis method. The mechanical properties, chemical stability, in vitro bioactivity, and antibacterial properties of the as‐synthesized GO/FHA composites with different GO amounts are reported. The result shows that the mechanical properties of the composites are strongly dependent on the adding amount of GO. The result of chemical stability indicates that the substitution of fluorine (F) into the hydroxyapatite (HA) crystal has a positive effect on the dissolution resistance. The in vitro bioactivity assessment shows that the osteoblast proliferation and differentiation ability on GO/FHA composites are improved.  相似文献   

12.
A novel low‐phosphorus terpolymer, used as scale, corrosion inhibitor, and dispersant for iron oxide, was prepared through free‐radical polymerization reaction of acrylic acid (AA), oxalic acid‐allypolyethoxy carboxylate (APEM), and phosphorous acid (H3PO3) in water with redox system of hypophosphorous and ammonium persulfate as initiator. Structure of the synthesized AA‐APEM‐H3PO3 terpolymer was characterized by Fourier transform infrared spectrometer and 1H‐NMR. The polymer possesses excellent scale inhibition performance for CaCO3, outstanding ability to disperse ferric oxide, and good corrosion inhibition properties. The study showed that AA‐APEM‐H3PO3 exhibited excellent ability to control calcium carbonate scale, with approximately 90.16% CaCO3 inhibition at a level of 8 mg/L AA‐APEM‐H3PO3. The data of the light transmittance showed that, compared to hydrolyzed polymaleic acid and polyepoxysuccinic acid, AA‐APEM‐H3PO3 had superior ability to control iron ions scaling. The light transmittance of the solution was about 24.1% in the presence of the terpolymer when the dosage was 8 mg/L. Moreover, the corrosion inhibition efficiency could reach up to 79.77% at a dosage of 30 mg/L, with ethylene diamine tetra methylene phosphonic acid just 39.62%. Scanning electronic microscopy, transmission electron microscope, and X‐ray powder diffraction analysis were used to investigate the effect of AA‐APEM‐H3PO3 on morphology of calcium carbonate scale. The low‐phosphorous terpolymer has also been proven to be effective inhibitor of calcium carbonate even at increasing solution temperature, pH, and Ca2+ concentration. The proposed inhibition mechanism suggests the surface complexation and chelation between the functional groups ? P(O) (OH)2, ? COOH and Ca2+, with polyethylene glycol segments increasing its solubility in water. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41447.  相似文献   

13.
《Ceramics International》2019,45(10):13011-13018
The electrochemical performance of lithium ion batteries depend largely on the structural properties of electrode materials. In this work, we propose an approach to synthesize lithium-rich layered oxides (LLOs) materials using a manganese dioxide (MnO2) template strategy, which could control the structure and particle size of final products via choosing different MnO2 templates. Through precisely optimizing, we successfully prepare cross-linked nanorods (CLNs) and agglomerate microrods (AMs) Li1.2Ni0.15Co0.1Mn0.55O2 cathode materials by using carbon-decorated MnO2 nanowires and MnO2 nanorods as templates, respectively. The lithium ion battery based on the CLNs exhibits excellent performance, delivering a high capacity of 286.2 mAh g−1 at 0.1 C and 237.5 mAh g−1 at 1 C. In addition, the device remains 98% and 89% of its initial capacity after 50 cycles at 0.1 C and 100 cycles at 1 C, respectively. The remarkable electrochemical performance can be mainly attributed to the cross-linked nanorods structure which can provide relatively shorter lithium ion diffusion length, larger reaction surface and more internal cavity. This universal structure engineering strategy may shed light on new material structures for high performance lithium-rich layered oxide cathode materials.  相似文献   

14.
This study describes a simple and effective method of synthesis of a polyurethane/graphene nanocomposite. Cationic waterborne polyurethane (CWPU) was used as the polymer matrix, and graphene oxide (GO) as a starting nanofiller. The CWPU/GO nanocomposite was prepared by first mixing a CWPU emulsion with a GO colloidal dispersion. The positively charged CWPU latex particles were assembled on the surfaces of the negatively charged GO nanoplatelets through electrostatic interactions. Then, the CWPU/chemically reduced GO (RGO) was obtained by treating the CWPU/GO with hydrazine hydrate in DMF. The results of X‐ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Raman analysis showed that the RGO nanoplatelets were well dispersed and exfoliated in the CWPU matrix. The electrical conductivity of the CWPU/RGO nanocomposite could reach 0.28 S m?1, and the thermal conductivity was as high as 1.71 W m?1 K?1. The oxygen transmission rate (OTR) of the CWPU/RGO‐coated PET film was significantly decreased to 0.6 cmm?2 day?1, indicating a high oxygen barrier property. This remarkable improvement in the electrical and thermal conductivity and barrier property of the CWPU/RGO nanocomposite is attributed to the electrostatic interactions and the molecular‐level dispersion of RGO nanoplatelets in the CWPU matrix. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43117.  相似文献   

15.
《Ceramics International》2016,42(4):5001-5010
Co and Mn co-doped with NiO nanostructued materials, such as, Ni0.95Co0.01Mn0.04O1−δ, Ni0.95Co0.04Mn0.01O1−δ and Ni0.95Co0.025Mn0.025O1−δ were synthesized by chemical synthesis route and studied for potential application as electrode materials for supercapacitors. The phase structure of the materials was characterized by X-ray diffraction (XRD) and the crystallographic parameters were found out and reported. FTIR (Fourier Transform Infrared) spectroscopy revealed the presence of M–O bond in the compounds. The particle size of the materials was found to be in the range of 291.5–336.5 nm. The morphological phenomenon of the materials was studied by scanning electron microscopy (SEM) and the particles were found to be in spherical shape with average grain size of 14–28 nm. EDAX analysis confirmed the presence of appropriate levels of elements in the samples. The in-depth morphological characteristics were also studied by HR-TEM (High Resolution Tunneling Electron Microscopy). Cyclic voltammetry, chronopotentiometry and electrochemical impedance measurements were applied in an aqueous electrolyte (6 mol L−1 KOH) to investigate the electrochemical performance of the Co and Mn co-doped NiO nanostructured electrode materials. The results indicate that the doping level of Co and Mn in NiO had a significant role in revealing the capacitive behaviors of the materials. Among the three electrode materials studied, Ni0.95Co0.025Mn0.025O1−δ electrode material shows a maximum specific capacitance of 673.33 F g−1 at a current density of 0.5 A g−1. The electrochemical characteristics of blank graphite sheet were studied and compared with the performance of Co/Mn co-doped NiO based electrode materials. Also, Ni0.95Co0.025Mn0.025O1−δ has resulted in a degradation level of 4.76% only after 1000 continuous cycles, which shows its excellent electrochemical performance, indicating a kind of potential candidate for supercapacitors.  相似文献   

16.
A new epoxy‐ended hyperbranched polyether (HBPEE) with aromatic skeletons was synthesized through one‐step proton transfer polymerization. The structure of HBPEE was confirmed by Fourier transform infrared spectroscopy (FTIR), and nuclear magnetic resonance (NMR) measurements. It was proved to be one high efficient modifier in toughening and reinforcing epoxy matrix. In particular, unlike most other hyperbranched modifiers, the glass transition temperature (Tg) was also increased. Compared with the neat DGEBA, the hybrid curing systems showed excellent balanced mechanical properties at 5 wt % HBPEE loading. The great improvements were attributed to the increased cross‐linking density, rigid skeletons, and the molecule‐scale cavities brought by the reactive HBPEE, which were confirmed by dynamical mechanical analysis (DMA) and thermal mechanical analysis (TMA). Furthermore, because of the reactivity of HBPEE, the hybrids inclined to form a homogenous system after the curing. DMA and scanning electron microscopy (SEM) results revealed that no phase separation occurred in the DGEBA/HBPEE hybrids after the introduction of reactive HBPEE. SEM also confirmed that the addition of HBPEE could enhance the toughness of epoxy materials as evident from fibril formation. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1064‐1073, 2013  相似文献   

17.
Graphene oxide (GO) modified expanded perlite (EP) was prepared as a new sorbent for solid phase extraction of Cu(II) and Pb(II) prior to determination by high-resolution continuum source flame atomic absorption spectrometry (HR-CS-FAAS). Characterization of the synthesized sorbent was proved by Fourier transform infrared spectroscopy (FT-IR); X-ray diffraction (XRD); Brunaer, Emmet, and Teller (BET); specific surface area; and scanning electron microscopy (SEM) techniques. Several parameters such as pH, eluent type and concentration, flow rate, sample volume, interfering ions, adsorption capacity of sorbent were investigated and optimized. The proposed method was successfully applied for spiked analysis of Cu(II) and Pb(II) ions in tap water and fruity sodas sample, and fine recoveries (relative error <10%) were obtained.  相似文献   

18.
A novel epoxidized hyperbranched poly(phenylene oxide) (EHPPO) is designed and synthesized successfully. The structure of EHPPO is characterized by Fourier transform infrared spectra‐ and quantitative 13C nuclear magnetic resonance spectrum. The synthesized EHPPO is added into diglycidyl ether of bisphenol A as a modifier in different ratios to form hybrids and cured by an anhydride curing agent. Effects of EHPPO addition on the properties of the cured hybrids are investigated. Thermal mechanical analysis results suggest that addition of EHPPO can increase the free volume of the cured hybrid materials. Dynamic mechanical analysis characterizations show that the crosslinking density increases with the increase in EHPPO content. Furthermore, addition of EHPPO results in an improvement in thermal and mechanical properties. The toughening mechanism is also discussed. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013  相似文献   

19.
In this study, the antibiotic erythromycin (Ery) was incorporated into chitosan (Ch)–alginate (A) and Ch–xanthan (X) membranes with the aim of using them as bioactive wound dressings. Drug incorporation was performed by direct addition (DA) to the polysaccharide mixture and by membrane impregnation in solution (IS). A higher incorporation efficiency was obtained for DA, but higher amounts of drug were loaded into membranes by the IS method (maxima ≈ 2.1 and 0.7 g/g for Ch–X and Ch–A, respectively) because the initial concentration of drug could be higher than that in the DA method. Ery release in phosphate‐buffered saline was slow, reaching about 12 and 32 mg of drug/g of membrane in 60 h for Ch–X and 4 and 16 mg/g for Ch–A by the DA and IS methods, respectively. With formulations prepared with IS, the required therapeutic dosage was reached within 60 h, whereas for those incorporating the drug by DA, prolonged use would be required. Both membrane types behaved as drug reservoirs, providing continuous antibiotic release to the wound site. Formulations with higher drug contents showed effective antibacterial activity against two species of bacteria commonly found in skin lesions, Staphylococcus aureus and Pseudomonas aeruginosa, and were thus potentially capable of protecting the wound site from bacterial attack. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43428.  相似文献   

20.
Graphene oxide nanosheets were decorated by amino‐silane modified silica nanoparticles. An electrostatic interaction between the negative charge of oxygen‐containing groups of graphene oxide and the positive charge of amino‐silane functional groups on the surface of silica nanoparticles plays a major role for the interfacial interaction of these two materials. The hybrid material was then used as a reinforcement in polypropylene (PP) composite. The increasing tensile strength at yield, tensile, and flexural modulus of the PP composite at a graphene oxide‐ amino‐silane silica loading content of 20 wt % are about 24.81, 55.52, and 30.35%, respectively, when compared with those of PP. It is believed that GO assists the dispersion of SiO2 nanoparticles to the polymer matrix because of its unique structure having hydrophilicity due to its oxygen functional groups and hydrophobicity owing to its backbone graphitic carbon structure. This hybrid material may also be used as the reinforcement in other polyolefins. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44382.  相似文献   

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