P(VDF-TrFE)-based polymer nanocomposites comprising of reduced graphene oxide decorated with CoFe2O4@MCM 41 for efficient microwave absorption in X-band

Lightweight polymer nanocomposites (PNCs) dispersed with nanofiller RGO/CoFe₂O₄@MCM41, namely RCM (using hydrothermal process), have been prepared and characterized. Using the solution cast technique, PNCs {(P(VDF-TrFE)/LiTFSI/EMIMTFSI) + x wt% RCM, where x = 5, 7.5, and 10 in wt%} have been successfully synthesized. The synthesized PNCs possess good structural, thermal, mechanical, and magnetic properties because of the dispersed nanofiller within the polymeric matrix, which forms a 3-dimensional interconnected conducting network. The optimized PFE15Li50IL7.5RCM polymer nanocomposite also exhibits total shielding effectiveness (SE_T) of ~19.88 dB at 9.2 GHz for a thickness of 1.18 mm corresponding to 89.07% effective absorption (A_eff) in the X-band (8.2–12.4 GHz).     

Graphene oxide & reduced graphene oxide polysulfone nanocomposite pellets: An alternative adsorbent of antibiotic pollutant-ciprofloxacin

Efficient nanocomposites, GO-Psf and RGO-Psf has been synthesised from polysulfone and graphene oxide. The synthesised nanomaterials were characterised using contact angle measurements, SEM, TEM, XRD, TGA, DSC, Raman and FT-IR analytical techniques. The reported polymeric nanomaterials are attractive due to their high surface area and thermal stability. The maximum adsorption capacity for ciprofloxacin is 82.781 mg/g and 21.486 mg/g on GO-Psf and RGO-Psf, respectively. The kinetic and adsorption analysis identifies the nanomaterials as attractive adsorbents for removal of antibiotic pollutant, ciprofloxacin from aqueous solution.     

PMMA/DEAM⁃RGO纳米复合材料的制备与性能测试

采用甲基丙烯酸二乙氨基乙酯(DEAM)对还原氧化石墨烯(RGO)进行表面改性,制备了DEAM-RGO/MMA分散液,再用乳液聚合法制备PMMA/DEAM-RGO纳米复合材料.采用傅里叶变换红外光谱仪、拉曼光谱仪、扫描电子显微镜、透射电子显微镜、X射线衍射仪、差示扫描量热仪和热重分析仪等对产物的结构与性能进行了分析和测试...     

Synthesis of cellulose/reduced graphene oxide/polyaniline nanocomposite and its properties

A series of conductive nanocomposites cellulose/reduced graphene oxide/polyaniline (cellulose/RGO/PANi) were synthesized via in situ oxidative polymerization of aniline on cellulose/RGO with different RGO loading to study the effect of RGO on the properties of nanocomposites. The results showed that when RGO is inserted into cellulose/PANi structure, its thermal stability and conductivity are increased. So that adding of only 0.3 wt% RGO into the cellulose/PANi structure, its conductivity is increased from 1.1 × 1 10^?1 to 5.2 × 110^?1 S/cm. Scanning electron microscopy results showed that the PANi nanoparticles are formed a continuous spherical shape over the cellulose/RGO template; this increases the thermal stability of nanocomposite.     

Heteroatom-doped reduced graphene oxide/polyaniline nanocomposites with improved n-type thermoelectric performance

Polyaniline (PANI) is a potential candidate for n-type thermoelectric (TE) materials owing to its intrinsic electrical conductivity, low thermal conductivity, and facile synthesis techniques. However, its low Seebeck coefficient and power factor have limited its widespread usage. In this study, nitrogen-doped, and sulfur-nitrogen co-doped reduced graphene oxide (rGO) were used for tuning the TE properties of PANI. Doped rGO and PANI/doped-rGO nanocomposites were prepared via hydrothermal technique and chemical oxidative polymerization respectively and thereafter characterized. The TE properties of the nanocomposites were also studied and an optimized Seebeck coefficient, power factor and zT value of −1.75 mV K⁻¹, 95 μW m⁻¹ K⁻² and 0.06, respectively were reported for the PANI nanocomposite containing 1 wt% sulfur-nitrogen co-doped rGO. These results suggest that PANI/heteroatom-doped rGO can serve as promising candidates for n-type based TE applications.     

Reduced graphene oxide reinforced PET/PBT nanocomposites: Compatibilization and characterization

This research work focused on the effects of different compatibilizers on the properties of reduced graphene oxide (rGO) reinforced poly(ethylene terephthalate) (PET)/poly(butylene terephthalate) (PBT) nanocomposites. The samples were prepared via melt compounding and injection molding methods. The Joncryl and glycidyl isooctyl polyhedral oligomeric silsesquioxane (GPOSS) were used as compatibilizers at different loading levels (0.5%-4%). The structural, thermal, mechanical, morphological, and electrical properties of the nanocomposites were investigated. The Fourier transform infrared analysis results revealed that no significant interaction was observed when GPOSS was added. On the other hand, there were more obvious changes in the peaks of the nanocomposite containing Joncryl. The thermal results showed that the compatibilizer addition caused small changes while rGO addition did not considerably affect the thermal stability of blend. The glass transition temperature of the nanocomposite significantly decreased with the addition of GPOSS. The tensile test indicated that compatibilizers improved the mechanical performance of PET/PBT/rGO nanocomposite.     

水热法制备还原氧化石墨烯及其导电性调控

导电性可调控的还原氧化石墨烯（rGO）在结构功能材料和化工新材料等领域具有重要的应用前景。本文利用水热还原法实现了rGO的绿色制备,并通过调控反应温度和时间,获得了电导率可控的rGO产品,其电导率范围为10^-4～1 S·cm^-1。采用UV-vis、FT-IR、XPS、SEM、XRD和Raman等表征方法系统研究了rGO还原过程中结构与组成的变化。发现GO还原过程中,其含氧官能团于120℃时开始明显分解,高于140℃后含量显著降低,GO片层sp2区域逐渐恢复,电导率逐渐增大到1 S·cm^-1,同时层间距从8.2 Å减少到3.6 Å（1 Å=0.1 nm）。对比热还原法,水热法有效避免了rGO片层的堆叠,产物分散性较好,有望规模化制备导电性可控的rGO产品。本研究成果对rGO生产和应用具有重要意义。     

Nonisothermal crystallization behaviors of poly(3‐hexylthiophene)/reduced graphene oxide nanocomposites

Poly(3‐hexylthiophene) (P3HT)/reduced graphene oxide (rGO) nanocomposites were prepared through in situ reduction of graphene oxide in the presence of P3HT. The nonisothermal crystallization behaviors of P3HT and P3HT/rGO nanocomposites were investigated by differential scanning calorimetry. The Avrami, Ozawa, and Mo models were used to analyze the nonisothermal kinetics. The addition of rGO remarkably increased the crystallization peak temperature and crystallinity of P3HT, but the crystallization half‐time revealed little variation. The crystallization activation energies were calculated by the Kissinger equation. The results suggested that rGO plays a twofold role in the nonisothermal crystallization of P3HT, that is, rGO promotes the crystallization of P3HT as nucleating agent, and meanwhile, it also restricts the motion of P3HT chains. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Ultrasound‐assisted emulsion polymerization of methyl methacrylate and styrene

In this article, we report on the effect of using ultrasound during emulsion polymerization. This work differs somewhat from that previously reported in that ultrasound is used in conjunction with conventional initiators. The aim is to observe the changes in the nature of polymerization and the synthesized polymer. In this work, reaction conditions and compositions typical of conventional emulsion polymerization are used. Azo‐bisisobutyronitrile and potassium per sulfate are the initiators used. The initial indication is that the rate of polymerization and the final conversion are higher when ultrasound is introduced into the polymerization system. This effect is more pronounced at lower temperatures (50°C) and low initiator concentrations (0.01%). At higher temperatures (70°C) the polymerization rate is seemingly unaffected by the use of ultrasound. The final product in all the experiments is a latex. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 101–104, 2000     

Properties and structural characterization of oxide starch/chitosan/graphene oxide biodegradable nanocomposites

Novel chitosan (CS)/oxidized starch (OST)/graphene oxide (GO) nanocomposites (COST/GO‐n) films are prepared in a casting and solvent evaporation method. Fourier transform infrared spectroscopy, X‐ray diffractions, atomic force microscopy, scanning electron microscopy, transmission electron microscopy, thermal gravimetric analysis, tensile testing, and moisture uptake are used to study the structure and properties of these nanocomposites. To indicate the effect of carboxyl groups of OST, some results of the properties of CS/starch/GO nanocomposite (CST/GO‐n) were selected for control experimentation. Compared with the control CST/GO‐n series, COST/GO‐n films, which have the same component ration showed higher tensile strength (σ_b) and lower elongation at break (ε_b). Additionally, in the COST/GO‐n series, the σ_b increased with an increase of GO loading. However, higher proportion of GO could result in aggregations of GO nanosheets and deterioration of the film properties. Compared with the COST/GO‐0, the values of σ_b and water resistance of the COST/GO‐4 containing 2.0 wt % of GO were improved by 57.7 and 20.1%, respectively. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and characterization of poly(ethylene tetrasulfide)/graphene oxide nanocomposites by in situ polymerization method

Poly(ethylene tetrasulfide) (PSP) is synthesized via interfacial polycondensation of 1,2 dichloroethane and sodium tetrasulfide, in the presence of graphene oxide (GO). This process resulted in homogeneously dispersed PSP/GO nanocomposites. Nanocomposites of 0.3 and 0.5?wt% of GO are synthesized and their morphology, chemical characteristics behavior are studied employing field emission scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction techniques. Thermal characterization of composites is performed by differential scanning calorimetry and thermogravimetry analysis. Results indicate that the addition of only small amounts (0.5?wt%) of well-dispersed GO can increase the melting point more than 16°C resulting in better thermal properties for the composite. The solubility of nanocomposite is also studied and results show that the solubility depends on solvent concentration in addition to reinforcement (GO) deals.     

Poly(methyl methacrylate) nanocomposite reinforced with graphene,graphene oxide,and graphite: a review

Poly(methyl methacrylate) (PMMA) is an important transparent thermoplastic polymer having appropriate strength, chemical, weathering, heat, and UV resistance. However, essential properties of this versatile polymer need to be enhanced for high-tech applications. Graphene has opened up a new vista for developing functional polymeric nanocomposite. Therefore, reinforcement of PMMA with graphene and related nanofiller has been focused in literature. This review basically highlights the fundamentals and characteristics of the significant classes of PMMA/graphene, PMMA/graphene oxide, and PMMA/graphite nanocomposite. Recent developments in the applications of PMMA/graphene-based nanofiller nanocomposite in biomedical, sensor, supercapacitor, flame retardant, and electromagnetic interference shielding materials were also comprehended.     

Poly(methyl methacrylate) nanocomposites based on graphene oxide: a comparative investigation of the effects of surface chemistry on properties and foaming behavior

The effects of oxygen functional groups and alkyl chains at the surface of graphene oxide (GO) on the thermal stability, mechanical properties and foaming behavior of poly(methyl methacrylate) (PMMA) nanocomposites were investigated. Alkyl‐functionalized GO (GO‐ODA) was prepared by grafting octadecylamine (ODA) on the surface of GO. PMMA/GO and PMMA/GO‐ODA nanocomposite were obtained by solution blending and were foamed using supercritical carbon dioxide (scCO₂). GO‐ODA, with the presence of alkyl chains, showed a better dispersion capability in PMMA matrix than GO with a large amount of oxygen functional groups. In addition, the good dispersion capability increased thermal stability and mechanical strength. In comparison with PMMA/GO samples foamed at 70 °C, PMMA/GO‐ODA nanocomposite foams displayed improved cell structures with higher cell density, smaller cell size and more homogeneous cell size distribution, which results from the strong heterogeneous nucleation due to alkyl chains on the GO surface. The foaming behaviors became more complicated at 80 °C as the GO might be intercalated and exfoliated with the aid of scCO₂, thus further enhancing the heterogeneous nucleation during the foaming process. The results indicated that the surface chemistry of GO was closely related to the properties and foaming behavior of the nanocomposites. © 2016 Society of Chemical Industry     

一种氧化还原石墨烯的稳定水溶液分散体的合成方法

提供了一种在聚苯乙烯磺酸钠（PSS）的帮助下,合成氧化还原石墨烯稳定水溶液分散体的简单方法。这种方法制备的分散体非常稳定,长达几个星期都没有聚集或者沉淀。通过各种方法对材料进行了表征。扫描电子显微镜（SEM）和紫外-可见光吸收光谱的结果表明PSS紧密地包裹住了石墨烯,形成功能化石墨烯;石墨烯的亲水性大大提高。傅里叶变换红外光谱（FTIR）表明O=S=O官能团的存在,说明石墨烯中存在PSS。X射线光电子能谱（XPS）提供了C/S的原子浓度比等,进一步说明了PSS的存在。结果表明,覆盖有PSS的氧化还原石墨烯能够应用于石墨烯的复合材料中。     

Polyaniline nanorod adsorbed on reduced graphene oxide nanosheet for enhanced dielectric,viscoelastic and thermal properties of epoxy nanocomposites

In this work, polyaniline nanorod adsorbed on reduced graphene oxide (P@G) hybrid filler was prepared via in situ polymerization of aniline monomer in the presence of reduced graphene oxide as template. Fourier transform infrared, X-ray diffraction, field emission scanning electron microscopy, and high-resolution transmission electron microscopy images revealed the formation of P@G hybrid. The P@G hybrid was dispersed in dichlorobenzene and then introduced into epoxy resin at different loadings. The epoxy nanocomposites containing 9 wt% P@G hybrids (E/P@G9) exhibited a maximum DC conductivity of 1.34 × 10⁻⁵ S/cm that is eight orders higher compared to pure epoxy. At 10³ Hz, a dielectric constant (ε′) of 163 was attained for E/P@G9, nearly 34 times higher than pure epoxy. A percolation threshold of 4 vol% was observed for ε′. Dynamic mechanical studies showed that significant enhancement in storage modulus values were exhibited for 3 and 5 wt% of hybrids. The glass transition temperature showed a maximum shift of 10°C to higher temperatures at 3 wt% loading of P@G hybrids (E/P@G3). The tensile strength, Young's modulus, and impact strength of the E/P@G3 nanocomposites enhanced by 19.7, 72, and 12%, respectively. The thermal stability of the epoxy nanocomposites also enhanced with the addition of P@G hybrid.     

Effect of electrolyte on the supercapacitive behaviour of copper oxide/reduced graphene oxide nanocomposite

Cupric oxide/reduced graphene oxide (CuO/rGO) nanocomposites were synthesized through a chemical reduction method using hydrazine hydrate as the reducing agent. The morphology, elemental composition, and bonding network of the CuO/rGOnanocomposites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy respectively. The XRD results reveal lattice spacing and lattice strain from 3.371 to 3.428 Å and 1.05 × 10⁻³to 5.44 × 10⁻³ respectively, with the increasing ratio of rGO: CuO from 1:1 to 1:5. The cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS)and galvanostatic charge-discharge (GCD) studyofCuO/rGOas the electrode material showed excellent super-capacitive behavior in H₂SO₄ over Na₂SO₄ electrolytes. Moreover CuO/rGO nanocomposites exhibited better capacitance retention in H₂SO₄(75.69%) compared to Na₂SO₄(12.06%).     

Effect of oxygen functional groups of reduced graphene oxide on the mechanical and thermal properties of polypropylene nanocomposites

Reduced graphene oxide (rGO) with various surface structures was prepared by reducing graphene oxide (GO) with hydrazine hydrate (N₂H₄), sodium borohydride (NaBH₄) and l ‐ascorbic acid, respectively. The resulting rGO were used to fabricate rGO/polypropylene (PP) nanocomposites by a melt‐blending method. The surface structure of rGO as well as multifunctional properties of rGO/PP nanocomposites were thoroughly investigated. It was shown that rGO with highest C/O ratio could be obtained by reducing GO with N₂H₄. The crystallization behaviors, tensile strength, thermal conductivity and thermal stability of rGO/PP nanocomposites were significantly improved with the increase of C/O ratio of rGO. For example, with only 1 phr (parts per hundred PP) rGO reduced by N₂H₄, the degree of crystallinity, tensile strength, maximum heat decomposition temperature and thermal conductivity of PP nanocomposite were increased by 6.2%, 20.5%, 48.0 °C and 54.5%, respectively, compared with those of pure PP. Moreover, the thermal degradation kinetics indicated that the decomposition activation energy of rGO/PP nanocomposites could be enhanced by adding rGO with higher C/O ratio. © 2018 Society of Chemical Industry     

Cobalt/graphene oxide nanocomposites: Electro-synthesis,structural, magnetic,and electrical properties

In this research, different samples of cobalt/graphene oxide nanocomposites were successfully synthesized electrochemically by applying different voltages. Their structure, magnetization and electrical properties were studied using X-ray diffractometer (XRD), field emission scanning electron microscope (FESEM), atomic force microscope (AFM), fourier transformation infrared (FT-IR), vibrating sample magnetometer (VSM), two point probe electrical conductivity meter, galvanostat/potentiostat, and universal testing machine. The results of structural characterization confirmed the formation of cobalt/graphene oxide nanocomposites. The FESEM images showed the porous flower-like structure of particles deposited on the graphene oxide sheets. The AFM images clearly showed the surface roughness and the dispersion of nanoparticles on graphene oxide sheets. Room-temperature magnetization values range from 18 emu g^?1 to 167 emu g^?1, depending on the applied voltage. In order to study the electrical properties of the nanocomposites, the volumetric resistivity and volumetric conductivity under different pressures and the current-voltage characteristic curves were measured. Based on the results, the nanocomposites synthesized by applying 8 V and 23 V show ohmic behavior and have the highest volumetric conductivity. The volumetric conductivity increases with increasing the pressure. The nanocomposite prepared by applying 23 V presents good structural, magnetic, and electrical properties.     

Synthesis of hydrophobic carbon nanotubes/reduced graphene oxide composite films by flash light irradiation

Carbon nanotubes/graphene composites have superior mechanical, electrical and electrochemistry properties with carbon nanotubes as a hydrophobicity boosting agent. Their extraordinary hydrophobic performance is highly suitable for electrode applications in lithium ion batteries and supercapacitors which often employ organic electrolytes. Also the hydrophobic features enable the oil enrichment for the crude oil separation from seawater. The ever reported synthesis routes towards such a composite either involve complicated multi-step reactions, e.g., chemical vapor depositions, or lead to insufficient extrusion of carbon nanotubes in the chemical reductions of graphene oxide, e.g., fully embedding between the compact graphene oxide sheets. As a consequence, the formation of standalone carbon nanotubes over graphene sheets remains of high interests. Herein we use the facile flash light irradiation method to induce the reduction of graphene oxides in the presence of carbon nanotubes. Photographs, micrographs, X-ray diffraction, infrared spectroscopy and thermogravimetric analysis all indicate that graphene oxides has been reduced. And the contact angle tests confirm the excellent hydrophobic performances of the synthesized carbon nanotube/reduced graphene oxide composite films. This one-step treatment represents a straightforward and high efficiency way for the reduction of carbon nanotubes/graphene oxides composites.

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