Functionalized Graphene Oxide Composites Research Articles

An Electrochemical Immunosensor Based on GO@CS for Highly Sensitive and Accurate Detection of Cardiovascular Markers-cTn- I

The hidden hazards of cardiovascular diseases (CVDs) are enormous, and there is a lack of early warning and prognostic risk assessment technologies. In this study, Cardiac troponin I (cTn-I), the “gold standard” for CVDs diagnosis, was selected as the target molecule, and chitosan functionalized graphene oxide composites (GO@CS) with excellent electrochemical performance were prepared as the electrode base material. Gold nanoparticles (AuNPs) were deposited on GO@CS by electrochemical deposition. Due to the large surface area, excellent electrical conductivity and good biocompatibility of GO@CS assembled with AuNPs provide abundant active sites for the immobilization of cTn-I antigen. Under the optimized experimental conditions, the fabricated immunosensor had a wide linear range of 2.44 × 10−2 ng ml−1 to 2.50 × 10 ng ml−1 and a low detection limit of 1.12 × 10−2 ng ml−1 (S/N = 3). This study achieves the highly sensitive identification and detection of trace amounts of cTn-I in complex biological samples, providing a convenient and efficient method for the detection of CVDs-related markers. It also provides a scientific basis, new technologies and new methods for the development of objective early warning techniques for CVDs and the study of related pathological mechanisms.

Highly Efficient Elimination of Pb+2 and Al+3 Metal Ions from Wastewater Using Graphene Oxide/3,5-Diaminobenzoic Acid Composites: Selective Removal of Pb2+ from Real Industrial Wastewater.

In this study, graphene oxide (GO) was functionalized with 3,5-diaminobenzoic acid (DABA) by a one-step method to produce functionalized graphene oxide (FGO). FGO is a new type of absorbent crystalline substance that has a high surface area and a large porosity site as well as a large number of dentate functional groups which lead to enhanced adsorption performance for heavy metal ions. The adsorption efficiency of FGO for Pb+2 and Al+3 metal ions was extra satisfactory when compared with GO due to the ease of design and the homogeneous structure of FGO. The structure of synthesized GO and FGO was confirmed by different techniques such as FTIR, XRD, TGA, BET nitrogen adsorption-desorption methods, and TEM analyses. The mass of utilized adsorbents, the pH of the medium, the concentration of ionic species in the medium, temperature, and process time were all investigated as variables in the adsorbent procedure. The experimental data recorded that the maximum adsorption efficiency of the 0.5 g/L FGO composite was 99.7 and 99.8% for Pb+2 and Al+3 metal ions, respectively, while in the case of using GO, the maximum adsorption efficiency was 92.6 and 91.9% at ambient temperature in a semineutral medium at pH 6 after 4 h. The adsorption results were in good conformity with the Freundlich model and pseudo-second-order kinetics for Pb+2 and Al+3 metal ions. Also, the reusability study indicates that FGO can be used repeatedly at least for five cycles with a slight significant loss in its efficiency.

High-performance symmetric supercapacitor based on new functionalized graphene oxide composites with pyrimidine nucleotide and nucleoside

Delivery of cytidine triphosphate (CTP) as pyrimidine nucleotide and Cytarabine or arabinosylcytosine (Ara-C) as pyrimidine nucleoside onto the surface of graphene oxide (GO) has led to the fabrication of effective composites of functionalized graphene oxides (FGO-CTP and FGO-Ara-C). In the present study, we have compared FGO-CTP and FGO-Ara-C composites as active electrodes in a system with three electrodes for electrochemical measurement. Also, the as-prepared composites exhibited an ideal supercapacitive behavior in a symmetric capacitor. For the two electrode arrangement, a capacitance of 212F g−1, an energy density of 17.8 Wh kg−1 at 325 W kg−1, and an outstanding life cycling was achieved for the FGO-CTP electrode within a voltage window of 0–1.3 V in 1 M H2SO4 electrolyte, demonstrating greater electrochemical behavior compared to that of FGO-Ara-C electrode. In addition, the DFT calculations and charge density analysis resulted in more charge distribution on the GO layer of FGO-CTP than that of FGO-Ara-C, making it more effective as an electrode material for supercapacitors. Taking advantage of the facile synthesis method for introducing phosphate functional groups onto the surface of graphene oxide opens up an effective way for the fabrication of high-performance devices with large active surface area and high electrochemical ability in energy storage systems. Also, the assembled device expands the practical application areas of electrochemical energy storage devices significantly.

A novel method for the functionalization of graphene oxide with polyimidazole for highly efficient adsorptive removal of organic dyes

Graphene oxide (GO) and its related composites have been extensively studied for various applications due to their unique two-dimensional structure and promising performance. In this study, we reported for the first time that polyimidazole-modified GO composites (abbreviated as PILGO) could be successfully fabricated through the combination of thiol-ene click and Radziszewski reactions. Functionalized GO composites were characterized by a series of techniques, such as nuclear magnetic resonance hydrogen spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis, and the adsorption behaviour of these PILGO composites towards Congo red (CR, an anionic dye) was investigated in detail. We demonstrated that the adsorption capacity of PILGO was significantly improved as compared with that of pristine GO. The maximum uptake performance of PILGO was up to 191.9 mg g−1 with a near-saturation state achieved in the first 5 min. The adsorption equilibrium data were better fitted through the pseudo-second-order model, while the adsorption isotherm data were better correlated with the Freundlich and Tempkin models. The adsorption affinity between CR and PILGO was positively related to the solution pH. The adsorption mechanism between CR molecules and composite material was further put forward, and it included electrostatic attraction, π-π stacking and hydrogen bond interactions. Competitive adsorption and cycling experiments further demonstrated that PILGO composites can be used as clean, efficient and novel adsorbents in wastewater treatment.

Insight into glass transition temperature and mechanical properties of PVA/TRIS functionalized graphene oxide composites by molecular dynamics simulation

Mechanical properties of polyvinyl alcohol (PVA) are of essential importance to the practical application. Much effort has been done to further improve the properties of PVA by modifiers. However, in-depth insight into the role of the modifiers in the properties of PVA at a molecular level still remains rare. Therefore, the Glass transition temperature (Tg) and mechanical properties of PVA, PVA/graphene oxide (GO) and PVA/TRIS functionalized graphene oxide (Tris-GO) are investigated by molecular dynamics (MD) simulation. The results indicate the volume of PVA, PVA/GO and PVA/Tris-GO regularly varies with temperature. The PVA/Tris-GO show a higher Tg compared to the PVA/GO owing to stronger hydrogen-bonding interactions. The Young’s modulus, Shear modulus and Cauchy pressure of PLA/Tris-GO nanocomposites are enhanced by 50%, 46%, and 40% at 2.5 wt% addition amount of Tris-GO. In addition, the introduction of Tris-GO can significantly reduce the mobility and flexibility of the PVA chains in the PVA/Tris-GO. The binding energy between PVA and Tris-GO is larger than that between PVA and GO, which leads to the improved mechanical properties of the PVA/Tris-GO. These simulation results provide a better understanding of the thermomechanical mechanism of PVA/Tris-GO nanocomposites, and an effective guidance for improving their mechanical properties.

Direct surface functionalization of graphene oxide with ionic liquid through gamma ray irradiation induced radical polymerization with remarkable enhanced adsorption capacity

Abstract A facile one-step synthesis method based on Gamma ray irradiation induced radical polymerization was proposed for the first time for preparation of graphene oxide-ionic liquid composites (GO@IL) using 3-n-Hexadecyl-1-vinylimidazolium bromide ([C16VIm+] [Br−]) as the monomer. The GO@IL composites were utilized as adsorbents for adsorption and separation of Sunset Yellow (SY) and chromium (Cr, VI) ions from the stock solution. The maximum adsorption capacities of prepared GO@IL to adsorb SY and Cr (VI) were observed in the acidic media at room temperature, with the maximum adsorption capacities of 169.6 and 75.8 mg g−1, respectively. Various adsorption kinetics and isotherm models were employed to fit adsorption data to better understand the adsorption process and behavior of contaminants onto GO@IL surfaces. The value of ΔG0 and ΔH0 implied the adsorption were initiative and endothermic nature for SY and Cr (VI). The electrostatic and π − π stacking interactions were expected to be involved in the adsorption for SY and Cr (VI) onto the functionalized graphene oxide composite. These data illuminate that the adsorption performance of graphene oxides has enhanced remarkable after polymerization with [C16VIm+] [Br−] on their surface. Considering the regeneration ability, the easily synthetic GO@IL composites with great promise applications for wastewater treatment and purification.

Heat tolerant epoxy-amine functionalized graphene oxide composites for insulation applications

Heat tolerant polymers are in much demand in electrical, structural, and electronic packaging applications. This article reports on a comparison of epoxy composites reinforced with graphene oxide (GO) and amine-functionalized GO (AGO) on their dielectric properties and adhesive strength in the temperature range of 30–110 °C. GO was synthesized using the modified Hummers method and functionalized with amine functional group using hexamethylenediamine (HMDA) and confirmed by Raman spectroscopy. Various filler concentrations (0.2–0.6 wt.%) of GO/AGO epoxy nanocomposites were prepared using the solution blending method and analyzed using a dynamic mechanical analyzer (DMA), impedance spectroscopy, and the single lap shear (SLS) test. Studies showed AGO reinforced epoxy composites outperforming than neat epoxy and GO-epoxy composites for all the compositions. The optimum concentration of AGO was found to be 0.4 wt.% based on its relative permittivity, dielectric loss and retention of adhesive strength up to 90 °C. The percentage of cohesive area on the fractured surface of SLS tested AGO was ∼1.4 and ∼3 times better than that of GO-epoxy and neat epoxy, respectively. The higher strength retention of AGO-epoxy nanocomposites is suitable for high-temperature insulation applications as adhesive coatings.

High flux hyperbranched starch-graphene oxide piperazinamide composite nanofiltration membrane

Polypiperazinamide membranes are most commonly used membranes for nanofiltration (NF) of solution. These membranes suffer low flux due to the relatively flexible hydrophobic backbone. Hydrophilic graphene oxide (GO) was incorporated in the top layer of these membranes to improve flux. However, GO is expensive therefore, the GO was modified with starch, a benign and inexpensive hydrophilic matrix to minimize the economic burden. Starch functionalized GO was added in the polypiperazinamide network to give high-flux hyperbranched starch functionalized graphene oxide composite (HGOST) nanofiltration membranes. GO-starch composites were integrated in the polyamide (PA) top layer by esterification. Abundant oxygen functional groups in starch and graphene oxide decreased contact angle to 22.18°. Permeance of the membranes increased to 79.6 L m−2 h-1 (LMH) with the addition of HGOST to the top layer, with slight increase in the ionic rejection. The use of starch decreased the amount of graphene oxide needed to improve performance by about 80%. Hydrophilic nature of starch-GO composite, its compatibility with the polypiperazinamide matrix and enhance surface negative charge on the membrane in combination with a thin top layer are responsible for enhanced performance. Excellent stability was obtained due to bonding between starch, GO and polypiperazinamide layer. Membranes displayed excellent rejection of charged and neutral dyes as well. The inclusion of GO-starch composites shows good promise for enhancing the performance of polyamide membranes.

High-efficiency adsorption of methylene blue dye from wastewater by a thiosemicarbazide functionalized graphene oxide composite

With the aim of developing an improved adsorbent material for the treatment of printing and dyeing wastewater, we prepared a novel thiosemicarbazide functionalized graphene oxide (GO-TSC-GO) adsorbent by condensation reaction of the thiosemicarbazide amino group with the graphene oxide carboxyl group. This material was characterized by SEM, XPS, FTIR, Raman, XRD, UV–Vis, TGA, and BET then used to conduct adsorption experiments on simulated printing and dyeing wastewater containing methylene blue (MB). We investigated the effects of temperature, time, pH, salt ionic strength, initial MB solution solubility, and the activation and regeneration of the adsorbent on adsorption performance. The adsorption behavior was consistent with the pseudo-second-order adsorption kinetic model and the Langmuir adsorption isotherm model. Thermodynamic analysis indicated an exothermic chemical adsorption reaction. In addition, the GO-TSC-GO exhibited excellent reusability. The maximum adsorption capacity of GO was 196.8 mg/g whereas the maximum adsorption capacity of GO-TSC-GO was 596.642 mg/g, verifying that the GO-TSC-GO composite has important applications for the treatment of printing and dyeing wastewater.

Copper(II)-β-cyclodextrin and CuO functionalized graphene oxide composite for fast removal of thiophenic sulfides with high efficiency

A novel copper(II)-β-cyclodextrin and CuO functionalized graphene oxide composite (CD-CuO/NH2-GO) was successfully synthesized by reacting mono-6-O-toluenesulfonyl-copper(II)-β-cyclodextrin with amino and CuO functionalized graphene oxide. The characterization results showed that the CD-CuO/NH2-GO was well-characterized and has a BET surface area of 746.5 m2 g−1 and good thermal stability, and CD and CuO were uniformly dispersed. The unique structure of CD-CuO/NH2-GO is conducive to the synergistic effect of the different components, especially for the inclusion ability of CD. Benefiting from that, CD-CuO/NH2-GO could quickly and efficiently remove the thiophenic sulfides, which are difficult to be economically removed by hydrodesulfurization. The removal efficiency for the three sulfides was in the order of benzothiophene > dibenzothiophene > thiophene. The desulfurization process of benzothiophene has the fastest desulfurization rate (0.121 g mg-1 min-1) and maximum sulfur capacity (12.75 mg S g-1). The different molecular inclusion ability of CD for the thiophenic sulfides demonstrates the difference in the desulfurization of CD-CuO/NH2-GO. The work highlights the synthesis and the potential application in fuel desulfurization of supramolecular GO composite nanomaterials.

Multifunctional silanized silica nanoparticle functionalized graphene oxide: polyetherimide composite film for EMI shielding applications

Synthesis of graphene oxide (GO) was done using graphite powder by Hummer’s modified method and it was functionalized using silanized silica nanoparticle. Various weight percentage of functionalized graphene oxide (FGO) in polyetherimide (PEI) matrix (0.5–3 wt%) nanocomposite films were synthesized using solution based method. Fourier transform infrared (FTIR) spectroscopy and X-ray diffraction (XRD) studies confirm the functionalization and partial reduction of GO. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies demonstrated the nanostructure of GO, FGO and PEI–FGO nanocomposite films. The electromagnetic interference (EMI) shielding effectiveness in comparison to pure polyetherimide (2–3 dB), nanocomposite with 1.5 wt% FGO loading exhibits upto 21–23 dB at frequency range 8–12 GHz. Dynamic mechanical analysis (DMA) elucidate the improvement of glass transition temperature and storage modulus (E′) of the PEI–FGO nanocomposite films. Variation in different experimental parameters such as frequency, temperature and filler loading were used to analyze the dielectric properties of the PEI–FGO nanocomposite films. Dielectric constant increases seven times and dielectric loss decreases 14 times for nanocomposites with 1.5 wt% FGO loading in PEI matrix as compared to pure polyetherimide. The bandgap decreases slightly for PEI–FGO composite due to an intermediate band in PEI band structure by FGO. The nanocomposite films also exhibited good dielectric, mechanical properties and excellent EMI shielding effectiveness at wide range of frequency and temperature.

Interaction between U(VI) with sulfhydryl groups functionalized graphene oxides investigated by batch and spectroscopic techniques

A novel 4-aminothiophenol functionalized graphene oxide composite (GO-SH) was prepared by an easy reaction route. Chemical structure and element analysis showed that the sulfhydryl groups (-SH) were successfully decorated on GOs. The sorption capacity toward U(VI) from aqueous solution was conducted by batch experiments. The results indicated the maximum sorption capacity of GO-SH composite toward U(VI) at pH = 5.5 and T = 298 K could reach 281.69 mg·g−1 on the base of the Langmuir model. The sorption kinetic curve for U(VI) fitted well with the pseudo-second-order model. X-ray photoelectron spectroscopy and infrared analysis demonstrated that the surface-grafted sulfhydryl groups contributed to the sorption of U(VI) by forming the surface complexation. The GO-SH also showed high stability and excellent reuse capability. Therefore, GO-SH can be regarded as a potential sorbent for the efficient removal of U(VI) from aqueous solutions.

Effective removal of heavy metals from aqueous solution by porous activated carbon/thiol functionalized graphene oxide composite

Effective removal of heavy metals from aqueous solution by porous activated carbon/thiol functionalized graphene oxide composite

Aminoazobenzene and diaminoazobenzene functionalized graphene oxides as novel class of corrosion inhibitors for mild steel: Experimental and DFT studies

In the present work aminoazobenzene (AAB) and diaminobenzene (DAB) functionalized graphene oxide composites have been synthesized and characterized by their FT-IR, XRD, TEM, Raman and XPS spectra. The inhibition effect of these two functionalized graphene oxides was evaluated on mild steel corrosion in 1 M hydrochloric acid solution using electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization methods. Electrochemical results showed that both the composites act as efficient corrosion inhibitors and their inhibition efficiencies increase with concentration. Aminoazobenzene functionalized graphene oxide (AAB-GO) and diaminobenzene functionalized graphene oxide (DAB-GO) exhibited maximum inhibition efficiencies of 94.65% and 92.04%, respectively at concentration as low as 25 mgL−1. Electrochemical impedance spectroscopy (EIS) study suggests that both investigated inhibitors inhibit mild steel corrosion by adsorbing on the metallic surface. Potentiodynamic polarization study suggests that studied composites act as mixed type inhibitors and predominantly behave as cathodic inhibitors. Scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS), and energy dispersive X-ray spectroscopy (EDX) techniques were used for surface characterization. EDX analysis further confirmed the adsorption of inhibitors onto the metallic surface. The several DFT based indices such as EHOMO, ELUMO, energy band gap (ΔE; ELUMO–EHOMO), global hardness (η), softness (σ) and fraction of the electron transfer (ΔN) show that AAB-GO is a better inhibitor than DAB-GO.

Synthesis, Characterization, and Bactericidal Evaluation of Chitosan/Guanidine Functionalized Graphene Oxide Composites.

In response to the wide spread of microbial contamination induced by bacterial pathogens, the development of novel materials with excellent antibacterial activity is of great interest. In this study, novel antibacterial chitosan (CS) and polyhexamethylene guanidine hydrochloride (PHGC) dual-polymer-functionalized graphene oxide (GO) (GO-CS-PHGC) composites were designed and easily fabricated. The as-prepared materials were characterized by Fourier transform infrared (FTIR), X-ray photoelectron spectrometer (XPS), field emission scanning electron microscopy (FE-SEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA) and Raman spectroscopy. Their antibacterial capability towards bacterial strains was also studied by incubating both Gram-negative bacteria and Gram-positive bacteria in their presence. More significantly, the synergistic antibacterial action of the three components was assayed, and the findings implied that the as-prepared GO-CS-PHGC shows enhanced antibacterial activity when compared to its single components (GO, CS, PHGC or CS-PHGC) and the mixture of individual components. Not only Gram-negative bacteria but also Gram-positive bacteria are greatly inhibited by GO-CS-PHGC composites. The minimum inhibitory concentration (MIC) value of GO-CS-PHGC against E. coli was 32 μg/mL. With the powerful antibacterial activity as well as its low cost and facile preparation, GO-CS-PHGC has potential applications as a novel antibacterial agent in a wide range of biomedical uses.

Epoxy/p‐phenylenediamine functionalized graphene oxide composites and evaluation of their fracture toughness and tensile properties

ABSTRACTIn an attempt to enhance the mechanical properties of epoxy/graphene‐based composites, the interface was engineered through the functionalization of graphene oxide (GO) sheets with p‐phenylenediamine; this resulted in p‐phenylenediamine functionalized graphene oxide (GO–pPDA). The morphology and chemical structure of the GO–pPDA sheets were studied by spectroscopic methods, thermal analysis, X‐ray diffraction, and transmission electron microscopy. The characterization results show the successful covalent functionalization of GO sheets through the formation of amide bonds. In addition, p‐phenylenediamine were polymerized on graphene sheets to form crystalline nanospheres; this resulted in a GO/poly(p‐phenylenediamine) hybrid. The mechanical properties of the epoxy/GO–pPDA composite were assessed. Although the Young's modulus showed improvement, more significant improvements were observed in the strength, fracture strain, and plane‐strain fracture toughness. These improvements were attributed to the unique microstructure and strong interface between GO–pPDA and the epoxy matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43821.

4-Mercaptophenylboronic acid functionalized graphene oxide composites: Preparation, characterization and selective enrichment of glycopeptides

Selective enrichment and isolation of glycopeptides from complex biological samples was indispensable for mass spectrometry (MS)-based glycoproteomics, however, it remained a great challenge due to the low abundance of glycoproteins and the ion suppression of non-glycopeptides. In this work, 4-mercaptophenylboronic acid functionalized graphene oxide composites were synthesized via loading gold nanoparticles on polyethylenimine modified graphene oxide surface, followed by 4-mercaptophenylboronic acid immobilization by the formation of Au–S bonding (denoted as GO/PEI/Au/4-MPB composites). The composites showed highly specific and efficient capture of glycopeptides due to their excellent hydrophilicity and abundant boronic acid groups. The composites could selectively capture the glycopeptides from the mixture of glycopeptides and nonglycopeptides, even when the amounts of non-glycopeptides were 100 times more than glycopeptides. Compared with commercial meta-amino phenylboronic acid agarose, the composites showed better selectivity when the sample was decreased to 10 ng. These results clearly verified that the GO/PEI/Au/4-MPB composites might be a promising material for glycoproteomics analysis.

High-rate lithium storage capability of cupric-cobaltous oxalate induced by unavoidable crystal water and functionalized graphene oxide

The combination of co-precipitation and dehydration is used to prepare hydrated and dehydrated cupric-cobaltous oxalates (Cu1/3Co2/3C2O4·xH2O, x = 1.4; Cu1/3Co2/3C2O4). Then, the hydrothermal treatment of these binary oxalates with freshly prepared graphene oxide (GO) and then dehydration are subsequently adopted to combine the hydrated or dehydrated oxalate with functionalized graphene oxide (FGO), resulting in another two targets of Cu1/3Co2/3C2O4·xH2O/FGO and Cu1/3Co2/3C2O4/FGO composites. These facilitate the comparative studies on the lithium storage capability of cupric oxalate-containing anode materials enhanced by unavoidable crystal water. As a lithium-ion battery anode, Cu1/3Co2/3C2O4·xH2O possesses a reversible capacity of 565.0 mAh g−1 at 1000 mA g−1 over 200 discharge-charge cycles, higher than that of the dehydrated counterpart (246.1 mAh g−1) but lower than those of FGO-based composites (Cu1/3Co2/3C2O4/FGO ∼ 951.2 mAh g−1; Cu1/3Co2/3C2O4·xH2O/FGO ∼ 1134.9 mAh g−1) continuously cycled at the exactly same conditions. At an ultra-high current density of 2000 or 5000 mA g−1, anode Cu1/3Co2/3C2O4·xH2O/FGO delivers a constant discharge capacity of 935.6 mAh g−1 in the 100th cycle or 388.9 mAh g−1 in the 1000th cycle, indicating a jointly positive effect of crystal water and FGO on the high-rate electrochemical performance of cupric-cobaltous oxalate for the first time.

A surfactant-free strategy for synthesizing reduced graphene oxide supported palladium nanoparticles with enhanced electrocatalytic performance towards formic acid oxidation

A simple noncovalent method is used to graft sulfonate (–SO3H) groups on a graphene oxide (GO) surface by the π–π stacking interaction between 1-propylsulfonic-3-methylimidazolium chloride and GO. The immobilization of sulfonate groups on the GO surface is confirmed by various physical techniques, such as X-ray photoelectron spectroscopy, ultraviolet and visible spectroscopy, and zeta potential analysis, etc. The as-prepared sulfonate functionalized GO composites (GO-SO3H) are further used as supporting material to anchor PdO·H2O nanoparticles through the slow hydrolysis of PdCl2. The sulfonate functionalized reduced GO composites (rGO-SO3H) supported Pd nanoparticles composites (Pd/rGO-SO3H) are obtained through the simultaneous reduction of PdO·H2O and the GO-SO3H with sodium borohydride. As shown by transmission electron microscopy, Pd nanoparticles with good dispersity effectively anchor on the rGO-SO3H surface. The as-prepared Pd/rGO-SO3H composites display the improved electrocatalytic activity and long-term stability towards the formic acid oxidation reaction compared to the un-sulfonated counterpart.

Pentadecane functionalized graphite oxide sheets as a tool for the preparation of electrical conductive polyethylene/graphite oxide composites

Covalent functionalization of pentadecane-decorated thermally reduced graphite oxide (GO) sheets has been studied as a tool for the preparation of polyethylene/GO composites exhibiting rheological and electrical percolation thresholds. It was accomplished through pentadecane based radical addition onto unsaturated bonds located on the GO sheets' surface using dicumyl peroxide as hydrogen abstractor. This chemical functionalization influences the affinity of the formed pentadecane grafted GO sheets for various solvents. Then, the compounding of the composites pentadecane grafted GO/PE was performed at a processing temperature of 140°C with 25, 20, 15, 10, 8 and 5wt% loadings. Rheological and electrical percolation thresholds were found between 10 and 15wt% for polyethylene/pentadecane functionalized graphene oxide composites while the composite graphite/PE at the same loading percentage did not reach any percolation threshold.