Weight Percentage Of Graphene Oxide Research Articles

Chitosan coated graphene oxide incorporated sodium alginate hydrogel beads for the controlled release of amoxicillin

Biopolymers are crucial in pharmaceuticals, particularly for controlled drug release. In this study, we loaded the broad-spectrum antibacterial drug amoxicillin into sodium alginate, a well-known biopolymer. Graphene oxide was incorporated into the composite, and the hydrogel beads were coated with chitosan for its mucoadhesive properties. Various composites were formulated by adjusting the weight percentage of graphene oxide (GO).The fabricated beads demonstrated controlled and sustained drug release, with 98 % of the loaded drug molecules released over 24 h at gastric pH. The antibacterial test using the disc diffusion technique confirmed the drug release, exhibiting greater effectiveness against the gram-positive bacterium S. aureus than the gram-negative bacterium E. coli. The drug release data were optimized using zero order, first order, Higuchi, and Korsmeyer-Peppas models. The experimental data were best fit to the Korsmeyer-Peppas model with a relatively higher correlation coefficient value. Biocompatibility was evaluated through a cell viability test using mouse fibroblast cell lines (L929). The MTT viability assay confirmed high levels of cytocompatibility, even at higher concentrations (100 μg/mL), with 98.15 % viable cells. These results highlight the potential of the fabricated beads as an effective amoxicillin drug delivery system with biomedical applications.

Characterization and room temperature ammonia sensing application of hydrothermally synthesized MoS2/RGO nanocomposites

Developing high-performance chemical gas sensor devices based on two-dimensional transition metal dichalcogenides (2D-TMDs) operating at room temperature is still a challenge due to the long and incomplete recovery. In this work, the hydrothermal technique was used to prepare molybdenum disulfide (MoS2)/reduced graphene oxide (RGO) nanocomposites at various amounts of graphene oxide (GO), and its effect on ammonia sensing has been investigated. For this, the weight percentage of GO to ammonium heptamolybdate tetrahydrate changed to 1 (MG1), 3 (MG3), 5 (MG5), and 10 (MG10). Raman analysis showed that the incorporation of GO causes the growth of the 1 T-MoS2 phase in nanocomposite samples. By examining the gas sensing properties of MoS2, RGO, and their nanocomposites, the optimal value of GO in MoS2 for the best performance of the sensor was achieved. The MG10 sample with the highest response (1.41 %), fastest response (58 s), and recovery (176 s) times under exposure to 500 ppm ammonia is the most suitable sensing material for fabricating ammonia sensors among other samples. This sample also showed excellent selectivity to ammonia compared to ethanol, methanol, and acetone. This study presents a new approach to exploit 2D nanocomposites for the detection of ammonia, as a biomarker in the human breath and also an important gas in industry.

Microstructure mechanical behavior of Cu-Sn alloy reinforced with Al2o3 and Graphene metal matrix composite

In the present study, an effort has been made to examine the Microstructure and Wear characteristics of composites manufactured from Cu + 10 wt% Sn alloy as matrix and reinforced with Graphene Oxide (GO) and Alumina. Cu + 10 wt% Sn alloy hybrid composites is prepared reinforced with alumina (10 vol%) and altering weight percentage of Graphene oxide (0.25 wt%, 0.5 wt% and 1 wt%) by spark plasma sintering technique. Wear characteristics of developed composites is studied using Pin on Disc Wear Testing machine. Utilizing optical microscopy the microstructural investigation is conducted. The results revealed that (Cu + 10 wt% Sn alloy-10 vol% Al2O3-0.25 wt% GO) and (Cu + 10 wt% Sn alloy-10 vol% Al2O3 − 0.5% wt%) of hybrid nanocomposite showed an increase of 25 % in the hardness, a reduction of 25% in the wear rate for Cu + 10 wt% Sn alloy-10 vol% Al2O3-0.25 wt% GO and Cu + 10 wt% Sn alloy-10 vol% Al2O3 − 0.5% wt% GO of hybrid nanocomposite, and an increase trend wear rate is observed with increase in applied load and disc speed in dry pin on disc wear testing. The result also revealed the uniform reinforcement distribution in microstructure and more than 95 % densification of all composites with spark plasma sintering process.

Tribological analysis of jute reinforced composites with different nano-fillers

This study investigates the carbon nanoparticle effects on the bulk and surface of jute-epoxy composites. Nano-fillers Graphene Oxide (GO) and Functionalized Graphene (FG) were used for Jute composite preparation. Tests like density, hardness, wear rate, specific wear rate, volumetric wear rate, are and wear resistance done to evaluate the tribological properties. Graphene Oxide and Functionalized Graphene as nano-fillers enhanced the tribological properties. The tribological test is carried by a pin on disc apparatus operating in dry atmospheric conditions and with different sliding speeds of (5 m/s), applied load (50 N), and distance of slide (10,000 m). The weight of fillers taken is (0.50,0.75, 1.0) weight percentage of Graphene Oxide and Functionalized Graphene nano-fillers. Test results showed that jute composite with 0.50 wt% of Functionalized Graphene and Graphene Oxide displayed improved performance at properties like hardness, wear resistance and volumetric wear loss in comparison to samples without any nano-fillers. After the addition of 0.50 wt.%, further addition of nano-fillers degrades the tribological properties of the sample.

Effect of temperature and oxygen functional groups on interaction between epoxy resins and graphene surface

Surface interactions between epoxy matrices and graphene nanosheets can directly affect the properties of nanocomposites, and such interactions are crucial to investigate. In this study, molecular dynamics simulation was used to investigate the interaction rate between epoxy thermoset resins (EPON 828, EPON 862, Epoxy Novolac, and Cycloaliphatic Epoxy) with graphene, and Functionalized Graphene with Oxygen Functional Groups. The effect of temperatures and different weight percentage of graphene oxide (1, 3, and 5 wt.%) was studied, and as a result of which it was observed that increasing the weight percentage of graphene oxide improved the interaction energy (adhesion) between epoxy resins and graphene oxide. Also, it decreased the radius of gyration (more contraction of epoxy molecules than graphene oxide nanosheets). In addition, increasing the temperature led to reduction of the interaction energy between epoxy resins and functionalized graphene. Moreover, escalating the temperature did not have any significant effect on the radius of gyration and Epoxy molecules resizing compared to graphene oxide nanosheets. The amount of interaction energy between epoxy resins and pristine graphene is very low in comparison with graphene oxide; therefore, temperature has a small effect on the amount of interaction energy and radius of gyration. Finally, the strongest interaction energy was found to be related to Epoxy Novolac and EPON 862 resins by comparing the interaction energy and radius of gyration between epoxy resins with graphene oxide. Therefore, they were the best candidates for matrixes in epoxy/graphene oxide nanocomposites.

Effect of adsorption, hardener, and temperature on mechanical properties of epoxy nanocomposites with functionalized graphene: A molecular dynamics study

Investigating Epoxy/hardener ratio and adsorption rate in epoxy/graphene oxide nanocomposites is of great importance, since these values can affect on the mechanical properties of the nanocomposite. In this study, molecular dynamics simulation was used to investigate and compare the mechanical properties of epoxy/graphene and graphene oxide nanocomposites (EPON 828, EPON 862, Epoxy Novolac, and Cycloaliphatic Epoxy with GNs and GO). Also, the effect of different weight percentages of graphene oxide (0,1,3 and 5 wt %), different weight percentages of epoxy compared to hardener, adsorption rate, and different temperatures were studied. The results showed that increasing the weight percentage of graphene oxide in epoxy matrices improved the adsorption rate between Epoxy/GO and the strength of nanocomposites. In addition, the amount of Young's modulus slightly decreased with increasing the temperature. Besides, the highest amount of Young modulus was obtained by increasing the weight percentage of epoxy to hardener at 63:37 wt %. Moreover, by comparing the mechanical properties of epoxy nanocomposites at 5 wt % graphene oxide, the highest Young modulus were found to be related to Novolac/GO 4.27 Gpa and EPON 862/GO 4.24 Gpa. This study contributes to a more comprehensive understanding on the behavior of the mechanical properties of epoxy/graphene oxide nanocomposites.

TiO2/graphene oxide nanocomposite with enhanced photocatalytic capacity for degradation of 2,4-dichlorophenoxyacetic acid herbicide

The present study investigates the photocatalytic degradation of 2,4-Dichlorophenoxyacetic acid (2,4-D), a hazardous herbicide using TiO2/Graphene oxide nanocomposite photocatalysts. The nanocomposite photocatalysts were synthesized via solvothermal method by varying the weight percentage of graphene oxide. The nanocomposite photocatalysts were examined by X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer Emmet Teller (BET) adsorption isotherm, Fourier-transform infrared (FT-IR) and UV–visible-diffuse reflectance spectroscopy (UV–Vis-DRS) analysis. The XRD pattern of nanocomposite was found unaltered, whereas a significant change around 33–91% was observed in the surface area of nanocomposites as compared to the pristine TiO2. The UV–Vis DRS study showed a blue shift in the band edge of the composites around 21–29 nm. The complete photocatalytic degradation of 2,4-D was achieved using TiO2/GO7% catalyst within 4 h of reaction under UV-light irradiation. The photocatalytic activity of the synthesized nanocomposite photocatalysts was also compared with the standard Degussa P-25 TiO2 photocatalyst. The order of photocatalytic activity of the synthesized photocatalysts were TiO2/GO7% > P25-TiO2 > TiO2/GO5% > TiO2/GO2% > TiO2/GO1% > TiO2/GO10% > TiO2/GO0.5% > Pristine-TiO2. This study offers a better platform for the synthesis of new composite photocatalytic materials for environment abatement by the degradation of organic pollutants.

Synthesis of Cu/rGO composites by chemical and thermal reduction of graphene oxide

In this work, synthesis of copper/reduced graphene oxide composites to increase the electrical conductivity of copper matrix has been carried out. Pure copper particles were mixed with 0.28 wt%, 1.1 wt% and 2.5 wt% graphene oxide (GO) contents. Different reduction methods were chosen to synthetize the Cu/rGO composite material: chemical reduction with hydrazine, thermal treatment at 815 °C in argon atmosphere. Characterization of the Cu/rGO composite disks was carried out by optical microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. Vickers Hardness and the electrical conductivity measured by Van der Pauw method of the Cu/rGO composites were analyzed. All the Cu/rGO disks showed lower hardness values than the Cu matrix. Microstructure of Cu/rGO composites is dominated by the presence of pores where GO agglomerates are accumulated and whose distribution and magnitude depends on the weight percentage of GO and the reduction process. Porosity percentage and pore size of Cu/rGO disks increase with GO content. Combination of chemical reduction with thermal treatment provides the most homogeneous microstructures with the smallest pore size and porosity percentage. Combination of both reduction treatments promotes more pathways for carrier transport within the reduced graphene oxide network structure, expanding areas of long-range conjugated structures and, consequently, increasing the electrical conductivity in the rGO/copper composites. Our research evidences that the Cu/rGO composites after chemical and thermal reduction increases the electrical conductivity, independently on the GO content, with respect to the pure copper matrix.

Stable composite of flower-like NiFe-layered double hydroxide nucleated on graphene oxide as an effective catalyst for oxygen reduction reaction

Nowadays, it is an urgent need but challenging to develop an efficient and resource-rich electrocatalysts with electrocatalysts activity for the oxygen reduction reaction (ORR) electrocatalyst. Therefore, we rationally designed and synthesized a unique 3-dimensional (3D) structure of flower-like NiFe-layered double hydroxide (NiFe-LDH) growing on graphene oxide (GO) with large surface area, widely-exposed active sites and good electrical conductivity, of which the weight percentage of GO in NiFe-LDH/GO was about 27.37%. Consequently, compared with pure NiFe-LDH (0.71 V (vs RHE), 95 mV dec−1) in alkaline electrolyte, the NiFe-LDH/GO possesses a relatively high onset potential of 0.88 V (vs RHE) and a smaller Tafel slope of 82 mV dec−1. Impressively, the prepared optimized NiFe-LDH/GO presents a highly stability than commercial Pt/C after stability testing due to strong interaction between graphene oxide and LDHs. In view of the above properties, these composite materials have better research prospects and open up a new opportunity for rational design.

Fabrication and Characterization of Graphene Oxide Doped SU-8 Polymer Waveguide

In this paper, graphene oxide (GO) was doped into SU-8 polymer to examine the functionalities of polymer waveguide material via dopant inclusion. In material preparation, step by step processes starting from cyclopentanone mixing will be explained. It is shown that doped material's refractive index can be tailored by having different weight percentage of GO. Finally, a single mode ridge waveguide loss of GO doped SU-8 has been characterized to be 1.9 dB/cm at 1550 nm wavelength.

Facile preparation of reduced graphene oxide/polypyrrole nanocomposites with urchin-like microstructure for wide-potential-window supercapacitors

Reduced graphene oxide (RGO)/polypyrrole (PPy) nanocomposites (GPs) with urchin-like and well-defined doping structure are synthesized by a very facile one-step method. The redox-active 1,4-benzoquinone, embedded in graphene oxide (GO) sheets, can be “in situ” served as both oxidant of PPy and its reduced state-hydroquinone used as the reductant of GO. One-dimensional nanowire-like PPys assembling on the two-dimensional RGO sheets formed three-dimensional urchin-like porous microstructure. The doping structure of the GPs can also be confirmed by N1s of X-ray photoelectron spectrometer results. As a result, the GPs provided dramatically improved specific capacitances as well as wider potential window compared with pristine GO and PPy. GP3 (the weight percentage of GO is 30 wt%) and GP5 (the weight percentage of GO is 50 wt%) supercapacitor devices also demonstrated high energy density as well as good cycling stability.

Characterization and mechanical properties of electrospun cellulose acetate/graphene oxide composite nanofibers

ABSTRACTGraphene oxide incorporated cellulose acetate composite nanofibers were prepared via an electrospinning technique. The weight percentage of graphene oxide varied from 0.05 to 1.5 wt.% in the polymer solution. The morphologies and crystal structures of the resultant composite nanofibers were investigated by scanning electron microscopy and X-ray diffraction. The specific interaction was demonstrated by Fourier-transform infrared spectroscopy. Tensile test was performed to measure the mechanical properties of the prepared cellulose acetate/graphene oxide composite nanofibers. 1.5 wt.% cellulose acetate/graphene oxide composite nanofibers showed the highest tensile strength and Young's modulus.

Investigation of the effect of graphene oxide on the properties of epoxy‐phthalonitrile nanocomposites

AbstractA novel keto‐ene containing phthalonitrile (PN) monomer was synthesized and characterized by Fourier transform infrared spectroscopy (FT‐IR) and 1H and 13C nuclear magnetic resonance spectroscopy. Graphene oxide (GO) was prepared from natural graphite using Hummer's method. The effect of the addition of GO with diglycidyl ether of bisphenol A (DGEBA) and phthalonitrile in the presence of diaminodiphenyl sulfone (DDS) as a curing agent has been investigated. The mechanical, thermal, and electrical properties of GO/epoxy‐phthalonitrile (EP‐PN) nanocomposites as a function of different weight percentage of GO (0, 1, 3, and 5 wt%) are reported. Dynamic mechanical analysis reveals that a maximum glass transition temperature (166.5°C) and storage modulus (3.3 GPa at 25°C) values are obtained for 3 wt% of GO content. FT‐IR, X‐ray diffraction, and Raman spectral techniques were employed to characterize the prepared GO and its extent of exfoliation in EP‐PN nanocomposites. The dispersion of GO in the fractured surface of the composites was analyzed by scanning electron microscopy and transmission electron microscopy. GO/EP‐PN nanocomposites show dramatic increase in dielectric properties compared to the neat EP‐PN nanocomposites. All the prepared nanocomposites fabricated with GO show excellent thermal stability in nitrogen atmosphere.

Electrical Properties of Conductive Nylon66/Graphene Oxide Composite Nanofibers.

In this paper, we report on the structural and electrical properties of graphene oxide (GO) incorporated Nylon66 (N66) composite nanofibers prepared via electrospinning technique. Different types of composite nanofibers were electrospun by varying the weight percentage of GO in the polymer solution. Scanning electron microscopy, X-ray diffraction and Fourier transform infrared spectroscopy, as well as current-voltage (I-V) measurements were used to characterize the N66/GO composite nanofibers. The morphology of the N66/GO composite nanofibers exhibited densely arranged mesh-like ultrafine nanofibers which were strongly bound in between the main fibers. The I-V characteristics of the N66/GO composite nanofibers demonstrated that the blending of GO in to N66 nanofibers led to a dramatic improvement of the electrical conduction compared to that of pristine N66 nanofibers which can be utilized for the various technological applications.

Preparation and properties of poly(dimethysilyleneethynylenephenylene‐ethynylene)/graphene Composites

Polymer composites with carbon‐based nano‐fillers have generated significant interest in industry and science because of their multifunctional and valuable properties. An APA‐functionalized GO nanofiller (GO–APA) was prepared through the reaction between graphene oxide (GO) and 3‐aminophenyl acetylene (APA) in dimethylformide (DMF) with ammonia hydroxide. Furthermore the PDSEPE/GO–APA composites were made from Poly(dimethysilyleneethynylenephenylene ethynylene) (PDSEPE) and GO–APA. FT‐IR, XRD, XPS, SEM, DSC and TGA techniques were used to characterize the chemical compositions and physical and chemical properties of GO–APA and PDSEPE/GO–APA composites. As a result, the prepared PDSEPE/GO–APA composites show high thermal stabilities, excellent electrical conductivity and good flexural strength. When the weight percentage of GO–APA reaches 0.5%, the PDSEPE/GO–APA composite electrical conductivity increases by 6 orders of magnitude and the flexural strength improves by nearly 33% compared with that of cured PDSEPE resin. Copyright © 2015 John Wiley & Sons, Ltd.

Preparation of Fe3O4-Embedded Graphene Oxide for Removal of Methylene Blue

Fe3O4-embedded graphene oxide was developed as a magnetic adsorbent for removal of methylene blue from aqueous solution. Fe3O4 nanoparticles were embedded on the surface of the as-prepared graphene oxide via a co-precipitation procedure with cheap and environmentally friendly iron salts. The weight percentage of graphene oxide was estimated by calcination to be about 18.5 %. In the aqueous solution of methylene blue at 20 °C, the adsorption data agreed well with the Langmuir adsorption model with a maximum adsorption capacity of 246 mg/g and a Langmuir adsorption equilibrium constant of 8.926 mL/mg. The adsorption amount increased with the increase of the solution pH (3–11), decreased with the increase of KCl concentration until it was up to 60 mM. The adsorbed methylene blue could be desorbed by using the methanol solution of acetic acid. In addition, both the adsorption and desorption rate were very quick that the equilibrium was achieved within 5 min due to the absence of the internal diffusion resistance. Fe3O4-embedded graphene oxide with large adsorption capacity and easy separation could be regarded as a potential adsorbent for removal of cationic dye in wastewater treatment process.

Assessment of morphology and property of graphene oxide-hydroxypropylmethylcellulose nanocomposite films

Graphene oxide (GO) was synthesized by Hummer's method and characterized by using Fourier transform infrared spectroscopy and Raman spectroscopy. The as synthesized GO was used to make GO/hydroxypropylmethylcellulose (HPMC) nanocomposite films by the solution mixing method using different concentrations of GO. The nanocomposite films were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and thermo-gravimetric analysis. Mechanical properties, water absorption property and water vapor transmission rate were also measured. XRD analysis showed the formation of exfoliated HPMC/GO nanocomposites films. The FESEM results revealed high interfacial adhesion between the GO and HPMC matrix. The tensile strength and Young's modulus of the nanocomposite films containing the highest weight percentage of GO increased sharply. The thermal stability of HPMC/GO nanocomposites was slightly better than pure HPMC. The water absorption and water vapor transmission rate of HPMC film was reduced with the addition of up to 1wt% GO.