Graphene Oxide Loading Research Articles

Research Progress on Photocatalytic Degradation of Methyl Orange Dye Wastewater by Light‐assisted Composite‐modified Ag3PO4

AbstractA new type of modified catalyst was prepared by a silver ammonia‐assisted precipitation method through a custom‐built electrochemical reactor, and the catalytic degradation of the azo dye methyl orange was studied under the synergistic effect of visible light. The optimum doping ratio for the loading of graphene oxide (GO) is 1.0 %. Under the optimum conditions, the degradation rate of Ag3PO4/GO/NiFe2O4 to methyl orange is 97.56 % when the light reaction time is 50 min. After three cycles, the degradation rate of methyl orange by Ag3PO4/GO/NiFe2O4 is 94.47 %. Through the free radical capture experiment, it is known that the contribution degree of the main active substances in the photocatalytic degradation of methyl orange is h + >⋅O2− >⋅OH. By forming a Z‐type heterojunction between Ag3PO4 and NiFe2O4, the recombination probability of photogenerated carriers is greatly reduced, and the stability of Ag3PO4 is improved.

Solid state engineering of Bi2S3/rGO nanostrips: an excellent electrode material for energy storage applications.

The study presents a novel, one-pot, and scalable solid-state reaction scheme to prepare bismuth sulphide (Bi2S3)-reduced graphene oxide (rGO) nanocomposites using bismuth oxide (Bi2O3), thiourea (TU), and graphene oxide (GO) as starting materials for energy storage applications. The impact of GO loading concentration on the electrochemical performance of the nanocomposites was investigated. The reaction follows a diffusion substitution pathway, gradually transforming Bi2O3 powder into Bi2S3 nanostrips, concurrently converting GO into rGO. Enhanced specific capacitances were observed across all nanocomposite samples, with the Bi2S3@0.2rGO exhibiting the highest specific capacitance of 705 F g-1 at a current density of 1 A g-1 and maintaining a capacitance retention of 82% after 1000 cycles. The superior specific capacitance is attributed to the excellent homogeneity and synergistic relation between rGO and Bi2S3 nanostrips. This methodology holds promise for extending the synthesis of other chalcogenides-rGO nanocomposites.

Bismuth ferrite based acetone gas sensor: evaluation of graphene oxide loading.

We report a BiFeO3/graphene oxide (BFO/GO) perovskite, synthesized using a CTAB-functionalized glycine combustion route, as a potential material for acetone gas sensing applications. The physicochemical properties of the developed perovskite were analysed using XRD, FE-SEM, TEM, HRTEM, EDAX and XPS. The gas sensing performance was analysed for various test gases, including ethanol, acetone, propanol, ammonia, nitric acid, hydrogen sulphide and trimethylamine at a concentration of 500 ppm. Among the test gases, the developed BFO showed the best selectivity towards acetone, with a response of 61% at an operating temperature of 250 °C. All the GO-loaded BFO samples showed an improved gas sensing performance compared with pristine BFO in terms of sensitivity, the response/recovery times, the transient response curves and the stability. The 1 wt% GO-loaded BiFeO3 sensor showed the highest sensitivity of 89% towards acetone (500 ppm) at an operating temperature of 250 °C. These results show that the developed perovskites have significant potential for use in acetone gas sensing applications.

Structural Formation and Pore Control of Freeze-Cast Directional Graphene Aerogel (DGA).

Directional graphene aerogels (DGAs) are proposed as electrode materials to alleviate ionic and mass transport issues in organic redox flow batteries (ORFBs). DGAs with high pore directionality would provide low resistance channels for effective ionic charge and liquid electrolyte transport in these devices. DGAs' porous and directional characteristics can be controlled by the growth of ice crystals during freeze casting, which is influenced by the self-diffusivity of water, phase change driving forces, water-ice graphene interactions, and convection in the water-graphene media. It is found that mass transport-related properties of DGAs, including pore size and directionality, show a significant dependence on freezing temperature, graphene oxide (GO) loadings, and synthesis vessel diameter-to-height ratio (D/H). For the freezing temperature change from -20 to -115 °C, the average pore size progressively decreased from 120 to 20 μm, and the pore directionality transitioned from lamellar to ill-defined structures. When GO loadings were increased from 2 to 10 mg/mL at a fixed freezing temperature, pore size reduction was observed with less defined directionality. Furthermore, the pore directionality diminished with an increased width-to-height aspect ratio of DGA samples due to the buoyancy-driven convective circulation, which interfered with the directional ice/pore growth. Understanding the comprehensive effects of these mechanisms enables the controlled growth of ice crystals, leading to graphene aerogels with highly directional microstructures.

Superior adsorptive removal of ciprofloxacin by graphene oxide modified Ni-Al layered double hydroxide composites

Pharmaceutical drug removal from industrial wastewater has become a major challenge in recent years. To address this concern, an eco-friendly, non-toxic, renewable, low-cost, and simple-to-synthesize catalyst called Ni-Al LDH (Layered Double Hydroxide) was synthesized using the co-precipitation method. LDH was further constructed with GO (Graphene Oxide) using the electro-self-assembly method for its effective performance in the removal of ciprofloxacin from wastewater. XRD, FESEM, EDX, Raman, FTIR, UV-Vis DRS, and BET analysis were used to characterize the as-prepared Ni-Al LDH and composites of GO@LDH. Using bare LDH and its composite with GO, several parameters such as adsorbent dosage, contact time, adsorbate concentration, and pH were optimized. GO(5)@LDH shows complete adsorption of 87.4% in 180 min for ciprofloxacin solution. The SBET for Ni-Al LDH, GO(1)@LDH, and GO(5)@LDH was determined to be in the order 3.5456 m2/g, 19.575 m2/g, and 22.5591 m2/g, suggesting that the surface area of the LDH increases upon GO loading. According to the calculation based on Langmuir isotherm, GO(5)@LDH (1968.5 mg/g) has a greater maximum adsorption capacity than Ni-Al LDH (332.2 mg/g). The kinetic analysis reveals that it adheres to a pseudo-second-order kinetic model. The catalyst was effectively employed for four repeating cycles with only a 10% decrease in removal rate, demonstrating that it can be easily regenerated. The morphology of the catalyst GO(5)@LDH remained the same before and after use, as seen by the XRD spectra, indicating the stability of the catalyst. As a result, LDH-GO composites are ideal catalysts for the treatment of ciprofloxacin wastes in the environment.

Regulation of interlayer channels of graphene oxide nanosheets in ultra-thin Pebax mixed-matrix membranes for CO2 capture

For the application of carbon capture by membrane process, it is crucial to develop a highly permeable CO2-selective membrane. In this work, we reported an ultra-thin polyether-block-amide (Pebax) mixed-matrix membranes (MMMs) incorporated by graphene oxide (GO), in which the interlayer channels were regulated to optimize the CO2/N2 separation performance. Various membrane preparation conditions were systematically investigated on the influence of the membrane structure and separation performance, including the lateral size of GO nanosheets, GO loading, thermal reduction temperature and time. The results demonstrated that the precisely regulated interlayer channel of GO nanosheets can provide rapidly CO2-selective transport channels due to the synergetic effects of size sieving and preferential adsorption. The GO/Pebax ultra-thin MMMs exhibited CO2/N2 selectivity of 72 and CO2 permeance of 400 GPU (1 GPU = 10–6 cm3(STP)·cm–2·s–1·cmHg–1), providing a promising candidate for CO2 capture.

Advanced Anticorrosive Graphene Oxide-Doped Organic-Inorganic Hybrid Nanocomposite Coating Derived from Leucaena leucocephala Oil.

Metal corrosion poses a substantial economic challenge in a technologically advanced world. In this study, novel environmentally friendly anticorrosive graphene oxide (GO)-doped organic-inorganic hybrid polyurethane (LFAOIH@GO-PU) nanocomposite coatings were developed from Leucaena leucocephala oil (LLO). The formulation was produced by the amidation reaction of LLO to form diol fatty amide followed by the reaction of tetraethoxysilane (TEOS) and a dispersion of GOx (X = 0.25, 0.50, and 0.75 wt%) along with the reaction of isophorane diisocyanate (IPDI) (25-40 wt%) to form LFAOIH@GOx-PU35 nanocomposites. The synthesized materials were characterized by Fourier transform infrared spectroscopy (FTIR); 1H, 13C, and 29Si nuclear magnetic resonance; and X-ray photoelectron spectroscopy. A detailed examination of LFAOIH@GO0.5-PU35 morphology was conducted using X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, and transmission electron microscopy. These studies revealed distinctive surface roughness features along with a contact angle of around 88 G.U preserving their structural integrity at temperatures of up to 235 °C with minimal loading of GO. Additionally, improved mechanical properties, including scratch hardness (3 kg), pencil hardness (5H), impact resistance, bending, gloss value (79), crosshatch adhesion, and thickness were evaluated with the dispersion of GO. Electrochemical corrosion studies, involving Nyquist, Bode, and Tafel plots, provided clear evidence of the outstanding anticorrosion performance of the coatings.

Facile synthesis of a GO-g-C3N4/BaTiO3 ternary nanocomposites for visible-light-driven photocatalytic degradation of rhodamine B

Photogenerated charge carriers can undergo rapid recombination in conventional photocatalyst systems, reducing their photocatalytic efficiency. To address this bottleneck, a g-C3N4/BaTiO3 (CNB) heterojunction composite was decorated with different mass ratios of graphene oxide (GO) to form a novel visible-light responsive ternary GO-g-C3N4/BaTiO3 (GOCNB) nanocomposite using a facile fabrication method. The GOCNB photocatalyst exhibited significantly higher light absorption and greater charge transfer than CNB, g-C3N4, or BaTiO3. The photodegradation performance of GOCNB was optimized with a 2% mass loading of GO, and it achieved a degradation rate constant of 14.9 × 10−3 min−1 for rhodamine B with an efficiency of 94% within 180 min. The rate constant was 8-fold and 6-fold higher than that of bare BaTiO3 and CNB, respectively. The stronger photocatalytic activity was attributed to the synergistic effect of GO, g-C3N4, and BaTiO3, with g-C3N4 and BaTiO3 promoting charge transfer within a wider visible light range and GO promoting electron mobility and the photocatalyst's adsorption capacity. In particular, the proposed system maintained the spatial separation of photogenerated electron–hole pairs, which is vital for high photocatalytic activity. This study provides new insights into semiconductor-based photocatalytic systems and suggests a route for more environmentally sustainable technologies.

Dielectric behavior and proton conductivity of ultrasound-assisted graphene oxide/sulfonated poly(ether ether ketone) composite electrolytes

This work deals with the evaluation of proton conductivity and dielectric measurements of graphene oxide (GO) doped sulfonated poly(ether ether ketone) (SPEEK) electrolytes for electrochemical devices. SPEEK-GO composite electrolytes were successfully prepared via ultrasound-assisted solution casting method. FTIR, SEM, and TGA analysis were performed to characterize the GO, SPEEK matrix, and current SPEEK-GO electrolytes. Additionally, the effects of GO loading on the proton conductivity and the dielectric behavior were also studied. The effectiveness of the oxy-groups in the GO structure for proton conduction via the Grotthus mechanism was demonstrated, and the SPEEK-GO-(10.0) composite electrolyte had the highest observed proton conductivity value of 4.79 × 10−3 S/cm. This value is roughly four times greater than the proton conductivity value of the pure SPEEK polymer matrix under the same conditions (400 K, 1 MHz), which is 1.23 × 10−3 S/cm. GO was able to increase the dielectric constant (ε′) both through its large surface area and aspect ratio and through its polar functional groups, which can interact with the SPEEK polymer matrix. The decrease in the electric modulus (M′) of the SPEEK-GO-(10.0) composite with increasing temperature could be attributed to both the decrease in the complex modulus and the formation of voids and gap at the interface between the polymer matrix and the GO particles.

Preparation and Catalytic Properties of Graphene Oxide/ Phosphotungstic Acid Composites

Background: Cellulose structures are in stable crystallineform. The hydrolysis of cellulose to small reducing sugars is difficult, but essential for its utilization Objective: To investigate the effect of graphene oxide (GO) loading on the catalytic performance of phosphotungstic acid (HPW) for the catalyzed hydrolysis of cellulose, with the purpose to get high yield of total reducing sugar (TRS). Methods: Graphene oxide/phosphotungstic acid (GO/HPW) composites were prepared using a liquid-phase composite method. The materials were applied to catalyze hydrolysis of microcrystalline cellulose in 1-butyl-3-methylimidazole chloride ionic liquid ([Bmim]Cl). The samples were characterized by Powder X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), Field emission scanning electron micrographs (FE-SEM), pyridine IR and acid-base chemical titration. Results: The Brønsted acidic sites were the main source of acidity in the composites and its concentration was determined to be 0.96 mmol/g. With the use of the GO/HPW composite as catalysts for cellulose hydrolysis, TRS yield of 90.5 % was obtained. Conclusion: GO/HPW composites retained the functional groups of both materials. It was the Brønsted acidic sites in the materials that effectively promoted the cellulose hydrolysis reaction. The structures of GO/HPW with the agglomeration of HPW scattered on GO had high accessibility of acidic sites and fast mass transfer of the reducing sugars to the outside of the catalysts in time to prevent their further conversion into by-products. TRS yield of 90.5 % was obtained from the hydrolysis of cellulose catalyzed by the GO/HPW (1:1.5) composites at 115 ℃ for 4 h using catalysts to cellulose 1:1 ratio.

Photocatalytic degradation of multiple-organic-pollutant under visible light by graphene oxide modified composite: degradation pathway, DFT calculation and mechanism

Wastewater containing antibiotics, organic dyes, and waterborne bacteria is a severe threat to human health and the environment. Amoxicillin has a slow metabolism rate in humans. Methylene blue is mutagenic and carcinogenic. In addition, Salmonella causes serious diarrhea. In this study, an effective 2D/2D photocatalyst with excellent elimination of these pollutants was fabricated by combining graphene oxide (GO), Bi2WO6, BiPO4 and Ag species. GO was applied at varying loading contents (0.8, 1.6, 2.4, 3.2 wt%) to improve the properties of the photocatalyst toward the removal of representative pollutants. The chemical structures, morphology, light absorption and charge mobility were investigated by different GO loading samples. The results indicated that when the wt% of GO was 2.4%, the photocatalyst showed excellent photocatalytic properties and removal rates for typical pollutants. Amoxicillin and methylene blue were mineralized into CO2, H2O, and small molecules, while Salmonella was disinfected with excellent photocatalytic efficiency. Furthermore, the possible photodecomposition pathways of amoxicillin and methylene blue were proposed by DFT calculations and intermediates identified by LCMS. The mechanism of the photocatalytic process was investigated by radical trapping experiments, ESR spectroscopy, and Motty-Schottky plots. The free radicals could be produced constantly during the photocatalytic process, leading to mineralization of amoxicillin and methylene blue, and disinfection of Salmonella. In this work, a new perspective on GO modified Bi2WO6 with different loading contents and the degradation pathways of antibiotics and dyes was proposed.

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) Bionanocomposites with Crystalline Nanocellulose and Graphene Oxide: Experimental Results and Support Vector Machine Modeling.

Poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) (PHBHHx) is a biodegradable and biocompatible bacterial copolymer used in the biomedical and food industries. However, it displays low stiffness and strength for certain applications. This issue can be solved via reinforcement with nanofillers. In this work, PHBHHx-based bionanocomposites reinforced with different loadings of crystalline nanocellulose (CNC) and graphene oxide (GO) were developed by a green and straightforward solution casting technique. Their crystalline nature and surface topography were explored via X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively, their composition was corroborated via Fourier-transformed infrared spectroscopy (FTIR), and their crystallization and melting behavior were determined via differential scanning calorimetry (DSC). The nanofillers had a nucleating role, raising the crystallization temperature of the polymer, whilst hardly any changes were found in the melting temperature. Further, significant enhancements in the stiffness, strength, and thermal stability of the PHBHHx matrix were observed with the incorporation of both nanofillers, which was attributed to a synergic effect. The mechanical properties for various concentrations of CNC and GO were accurately predicted using a machine learning (ML) model in the form of a support vector machine (SVM). The model performance was evaluated in terms of the mean absolute error (MAE), the mean square error (MSE), and the correlation coefficient (R2). These bio-based nanocomposites are a valuable alternative to conventional petroleum-based synthetic polymeric materials used nowadays for biomedicine and food packaging applications.

Effect of graphene oxide loading on the performance of melanized corn oil based polymeric nanocomposite coatings

AbstractIn this work, melanized corn oil (CO)‐based polymer was synthesized and was further engineered using three different ratios of graphene oxide (GO). The polymer nanocomposite thus formed was evaluated using various standard techniques to check the efficacy of GO nanosheets on the overall coating performance. Fourier transform infrared and x‐ray photoelectron spectroscopy techniques helped in structural elucidation of the prepared resins. The thermal stability of melanized CO based dihydroxy compound (CmDHC) was found to enhance up to 315°C on the incorporation of 0.5 wt% GO nanosheets. Furthermore, the scanning electron microscopy results revealed that incorporation of GO improved the surface roughness of CmDHC@GO2 nanocomposite coatings. This amplified surface roughness resulted in increased hydrophobicity with contact angle value of 78° as well as excellent corrosion resistance of 29.5 × 106 Ω cm2. The overall results suggest that dispersion of GO nanosheets into the polymer matrix helped to improve the mechanical, thermal as well as corrosion resistance performance of these coatings and 0.5 wt% was the optimum amount required for the same.Highlights GO nanosheets were dispersed in melanized CO‐based polymer matrix. Incorporation of GO nanoparticles in CmDHC polymer matrix enhanced the coating resistance almost 30 times. GO inhibited the corrosive ions effectively that resulted in excellent corrosion resistive performance. 0.5 wt% GO was the optimum amount to produce torturous path for corrosive ions. Overall CmDHC@GO2 nanocomposite exhibited excellent coating performance.

Polymer-aided microstructuring of moisture-stable GO-hybridized MOFs for carbon dioxide capture

MOF-based hybrid adsorbents for carbon capture are gaining increased attention as they can enhance key performance properties and scalability of MOFs. Yet, structuring these complex materials into mm-sized shaped particles to be used in actual process while maintaining the performance characteristics of the original powdered hybrids is challenging. In this work, a water-stable MOF (MIL-101(Cr)) was hybridized with graphene oxide (GO) yielding a hybrid adsorbent with enhanced CO2 capture performance, and the hybrid was then structured into mechanically robust spherical polyacrylonitrile-based beads of ∼ 2–3 mm in size exhibiting hierarchical porosity and high MOF loading (up to 80%) using a novel, simple, and scalable strategy. The powdered hybrid adsorbent with an optimum GO loading of 6 wt.% exhibited a 55% higher CO2 adsorption capacity and a 48% higher CO2/N2 selectivity than those of the parent MOF at 298 K and 1 bar, while the structured analogue provided high dispersion of the MOF@GO powder and preserved the CO2 adsorption performance and porosity characteristics of the original MOF@GO, making the resulting beads suitable and ready-to-use for practical CO2 capture application.

Synthesis of Au-Ag bimetallic nanoparticles using Korean red ginseng (Panax ginseng Meyer) root extract for chemo-photothermal anticancer therapy.

Green synthesis strategies have been widely applied for the preparation of versatile nanomaterials. Gold nanospheres with an average size of 6.95 ± 2.25nm were green synthesized by using a 70% ethanol extract of Korean red ginseng (Panax ginseng Meyer) root as a reducing agent. A seed-mediated synthesis was conducted to prepare Au-Agbimetallic nanoparticles using gold nanospheres as seeds. Remarkably, Au-Ag bimetallic nanoparticles with an average size of 80.4 ± 11.9nm were synthesized. Scanning transmission electron microscopy, energy dispersive X-ray spectroscopy and elemental mappings revealed bimetallic nanoparticles with Au-Ag alloy core and Au-rich shells. A face-centered cubic structure of Au-Ag bimetallic nanoparticles was confirmed by X-ray diffraction analysis. For Au-Ag bimetallic nanoparticles, the ratio of Ag/Au was 0.20 which was detected and analyzed by inductively coupled plasma-mass spectrometry. Gold nanospheres and Au-Ag bimetallic nanoparticles were functionalized by PEGylation, folic acid conjugation and grafting onto graphene oxide. Finally, docetaxel was loaded for evaluating the in vitro cell viability on cancer cells. Successful functionalization was confirmed by Fourier-transform infrared spectra. The anticancer activity of the docetaxel-loaded nanoparticles was higher than that of their non-docetaxel-loaded counterparts. The highest anticancer activity on human gastric adenocarcinoma cells (AGS) was observed in the docetaxel-loaded gold nanospheres that were functionalized by PEGylation, folic acid conjugation and grafting onto graphene oxide. Additionally, grafting onto graphene oxide and docetaxel loading induced high intracellular reactive oxygen species generation. For chemo-photothermal (PTT) anticancer therapy, cell viability was investigated using near-infrared laser irradiation at 808nm. The highest chemo-PTT anticancer activity on AGS cells was observed in the docetaxel-loaded Au-Ag bimetallic nanoparticles. Therefore, the newly prepared docetaxel-loaded Au-Ag bimetallic nanoparticles in the current report have potential applications in chemo-PTT anticancer therapy.

Production and Characterization of Graphene Oxide Surfaces against Uropathogens

Graphene and its functionalized derivatives have been increasingly applied in the biomedical field, particularly in the production of antimicrobial and anti-adhesive surfaces. This study aimed to evaluate the performance of graphene oxide (GO)/polydimethylsiloxane (PDMS) composites against Staphylococcus aureus and Pseudomonas aeruginosa biofilms. GO/PDMS composites containing different GO loadings (1, 3, and 5 wt.%) were synthesized and characterized regarding their morphology, roughness, and hydrophobicity, and tested for their ability to inhibit biofilm formation under conditions that mimic urinary tract environments. Biofilm formation was assessed by determining the number of total and culturable cells. Additionally, the antibacterial mechanisms of action of GO were investigated for the tested uropathogens. Results indicated that the surfaces containing GO had greater roughness and increased hydrophobicity than PDMS. Biofilm analysis showed that the 1 wt.% GO/PDMS composite was the most effective in reducing S. aureus biofilm formation. In opposition, P. aeruginosa biofilms were not inhibited by any of the synthesized composites. Furthermore, 1% (w/v) GO increased the membrane permeability, metabolic activity, and endogenous reactive oxygen species (ROS) synthesis in S. aureus. Altogether, these results suggest that GO/PDMS composites are promising materials for application in urinary catheters, although further investigation is required.

Advanced toluene/n-heptane separation by pervaporation: investigating the potential of graphene oxide (GO)/PVA mixed matrix membrane

BackgroundThe separation and purification of aromatic/aliphatic hydrocarbon mixtures from petroleum feedstocks is a significant industrial undertaking that poses several challenges. This task is commonly encountered during the production of ultralow-sulfur gasoline and naphtha reforming processes, both of which are critical for various industries. Recently, membrane pervaporation for separating aromatic/aliphatic mixtures is regarded as a promising option compared to conventional methods due to its energy efficiency. MethodThe preparation of a cross-linked polyvinyl alcohol (PVA) membrane with varying molecular weights, is aimed at effectively separating toluene/n-heptane. To further enhance the separation efficiency, mixed matrix membranes (MMMs) were fabricated by incorporating graphene oxide (GO) at different loadings. Significant findingsThe PVA membrane with a molecular weight of 130,000 was utilized as the polymer phase, as it exhibited a permeation flux of 24.8 g/m2h and a separation factor of 5.5. Increasing the GO loading from 0.5 to 1.5 wt% increased total flux; however, further increments in GO content led to a decrease in flux. Notably, the PVA-1.5GO sample demonstrated optimum performance, with a total permeation flux of 30.6 g/m2h, separation factor of 11.9. For this sample, pervaporation separation index (PSI) of 333.54 was obtained, indicating a 199% increase compared to that of pure PVA membrane (111.4).

Injectable and Self-Healable Thermoresponsive Hybrid Hydrogel Constructed via Surface-Modified Graphene Oxide Loading Exosomes for Synergistic Promotion of Schwann Cells

Injectable and Self-Healable Thermoresponsive Hybrid Hydrogel Constructed via Surface-Modified Graphene Oxide Loading Exosomes for Synergistic Promotion of Schwann Cells

Structure and Properties of Polystyrene-Co-Acrylonitrile/Graphene Oxide Nanocomposites

Polymer/graphene nanocomposites have attracted significant attention from the research community over the past two decades. In this work, nanocomposites of polystyrene-co-acrylonitrile (SAN) and graphene oxide (GO) were prepared using a solution blending method with tetrahydrofuran as the solvent. The GO loadings used were 0.1, 0.25, 0.5, and 1.0 wt.%. Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy were employed to characterize the structure and morphology of SAN/GO nanocomposites. Thermal analysis showed increases in the glass transition (Tg) and peak thermal degradation (Tdpeak) temperatures of SAN by the additions of GO, with Tg increasing by 3.6 °C and Tdpeak by 19 °C for 1.0 wt.% GO loading. Dynamic mechanical analysis revealed that the storage modulus of SAN was also enhanced with the incorporations of GO by up to 62% for 1.0 wt.% loading. These property enhancements may be attributed to a good dispersion of GO in the polymer matrix and their interfacial interactions.

Recycled polystyrene/polyvinylpyrrolidone/reduced graphene oxide nanocomposites for optoelectronic devices

Polymer nanocomposites based on recycled polystyrene (PS) and polyvinylpyrrolidone (PVP) with various reduced graphene oxide (rGO) loadings were prepared through a facile casting technique for enhancing the electrical conductivity of the insulator waste polystyrene to be applicable in electronic devices. The prepared nanocomposites were investigated by different techniques. FTIR analysis shows a reduction and shift of the main vibrational peaks of the blend, which confirms the introduction of (rGO) to the polymeric matrix, while XRD diffractograms provide complementary evidence for the transformation of graphene oxide into (rGO). The SEM image of the fractured edge of the sample points to a homogenous distribution of the PVP inside the major phase of the PS matrix. Moreover, the TEM image shows graphene oxide nanoparticles appearing in the form of dark lamellar structures with some light dots on a gray background, representing the polymeric domain. Besides, the TGA shows the existence of (rGO) led to some shifts in the PS and PVP onset decomposition temperatures when compared to the reference blend sample. Besides, the conductivity and dielectric properties of the prepared nanocomposites were characterized over a wide frequency range. Introducing (rGO) considerably enhanced their dielectric constant and ionic conductivity. The conductivity of these nanocomposites ranged from 10−11 to 10−6 S/m. The dielectric constant and dielectric loss of these composites were tested through frequencies, 0.1 Hz - 1 MHz, at 30 °C. The obtained values of the dielectric constant, loss tangent, and DC conductivity (σdc) suggested that the prepared nanocomposites could be used in various technological sectors such as energy storage, electronics, anti-static, and electro-static dissipation applications.