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pISSN : 1976-4251 / eISSN : 2233-4998

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2016, Vol.18, No.

  • 1.

    A review: role of interfacial adhesion between carbon blacks and elastomeric materials

    Kang Min Joo | 허영정 | Fan-Long Jin and 1other persons | 2016, 18() | pp.1~10 | number of Cited : 2
    Carbon blacks (CBs) have been widely used as reinforcing materials in advanced rubber composites. The mechanical properties of CB-reinforced rubber composites are mostly controlled by the extent of interfacial adhesion between the CBs and the rubber. Surface treatments are generally performed on CBs to introduce chemical functional groups on its surface. In this study, we review the effects of various surface treatment methods for CBs. In addition, the preparation and properties of CB-reinforced rubber composites are discussed.
  • 2.

    Monolithic porous carbon materials prepared from polyurethane foam templates

    João Pires | André Janeiro | Filipe J. Oliveira and 2other persons | 2016, 18() | pp.11~17 | number of Cited : 0
    Monolithic carbon foams with hierarchical porosity were prepared from polyurethane templates and resol precursors. Mesoporosity was achieved through the use of soft templating with surfactant Pluronic F127, and macroporosity from the polyurethane foams was retained. Conditions to obtain high porosity materials were optimized. The best materials have high specific surface areas (380 and 582 m2 g–1, respectively) and high electrical conductivity, which make them good candidates for supports in sensors. These materials showed an almost linear dependence between the potential and the pH of aqueous solutions.
  • 3.

    Microstructural changes of polyacrylonitrile-based carbon fibers (T300 and T700) due to isothermal oxidation (1): focusing on morphological changes using scanning electron microscopy

    Oh Seong-Moon | LeeSangMin | 강동수 and 1other persons | 2016, 18() | pp.18~23 | number of Cited : 3
    Polyacrylonitrile (PAN)-based carbon fibers have high specific strength, elastic modulus, thermal resistance, and thermal conductivity. Due to these properties, they have been increasingly widely used in various spheres including leisure, aviation, aerospace, military, and energy applications. However, if exposed to air at high temperatures, they are oxidized, thus weakening the properties of carbon fibers and carbon composite materials. As such, it is important to understand the oxidation reactions of carbon fibers, which are often used as a reinforcement for composite materials. PAN-based carbon fibers T300 and T700 were isothermally oxidized in air, and microstructural changes caused by oxidation reactions were examined. The results showed a decrease in the rate of oxidation with increasing burn-off for both T300 and T700 fibers. The rate of oxidation of T300 fibers was two times faster than that of T700 fibers. The diameter of T700 fibers decreased linearly with increasing burn-off. The diameter of T300 also decreased with increasing burn-off but at slower rates over time. Cross-sectional observations after oxidation reactions revealed hollow cores in the longitudinal direction for both T300 and T700 fibers. The formation of hollow cores after oxidation can be traced to differences in the fabrication process such as the starting material and final heat treatment temperature.
  • 4.

    Sorption behavior of slightly reduced, three-dimensionally macroporous graphene oxides for physical loading of oils and organic solvents

    PARK, HOSEOK | Sung-Oong Kang | 2016, 18() | pp.24~29 | number of Cited : 0
    High pollutant-loading capacities (up to 319 times its own weight) are achieved by three-dimensional (3D) macroporous, slightly reduced graphene oxide (srGO) sorbents, which are prepared through ice-templating and consecutive thermal reduction. The reduction of the srGO is readily controlled by heating time under a mild condition (at 1 10–2 Torr and 200°C). The saturated sorption capacity of the hydrophilic srGO sorbent (thermally reduced for 1 h) could not be improved further even though the samples were reduced for 10 h to achieve the hydrophobic surface. The large meso- and macroporosity of the srGO sorbent, which is achieved by removing the residual water and the hydroxyl groups, is crucial for achieving the enhanced capacity. In particular, a systematic study on absorption parameters indicates that the open porosity of the 3D srGO sorbents significantly contributes to the physical loading of oils and organic solvents on the hydrophilic surface. Therefore, this study provides insight into the absorption behavior of highly macroporous graphene-based macrostructures and hence paves the way to development of promising next-generation sorbents for removal of oils and organic solvent pollutants.
  • 5.

    Photocatalytic degradation and antibacterial investigation of nano synthesized Ag3VO4 particles @PAN nanofibers

    Prem Singh Saud | Zafar Khan Ghouri | Bishweshwar Pant and 4other persons | 2016, 18() | pp.30~36 | number of Cited : 3
    Well-dispersed Ag3VO4 nanoparticles @polyacrylonitrile (PAN) nanofibers were synthesized by an easily controlled, template-free method as a photo-catalyst for the degradation of methylene blue. Their structural, optical, and photocatalytic properties have been studied by X-ray diffraction, transmission electron microscopy, field-emission scanning electron microscopy equipped with rapid energy dispersive analysis of X-ray, photoluminescence, and ultraviolet–visible spectroscopy. The characterization procedures revealed that the obtained material is PAN nanofibers decorated by Ag3VO4 nanoparticles. Photocatalytic degradation of methylene blue investigated in an aqueous solution under irradiation showed 99% degradation of the dye within 75 min. Finally, the antibacterial performance of Ag3VO4 nanoparticles @PAN composite nanofibers was experimentally verified by the destruction of Escherichia coli. These results suggest that the developed inexpensive and functional nanomaterials can serve as a non-precious catalyst for environmental applications.
  • 6.

    Atmospheric chemical vapor deposition of graphene on molybdenum foil at different growth temperatures

    Samira Naghdi | Rhee Kyong Yop | Man Tae Kim and 2other persons | 2016, 18() | pp.37~42 | number of Cited : 0
    Graphene was grown on molybdenum (Mo) foil by a chemical vapor deposition method at different growth temperatures (1000°C, 1100°C, and 1200°C). The properties of graphene were investigated by X-ray diffraction (XRD), X-ray photoelectron spectroscopy, and Raman spectroscopy. The results showed that the quality of the deposited graphene layer was affected by the growth temperature. XRD results showed the presence of a carbide phase on the Mo surface; the presence of carbide was more intense at 1200°C. Additionally, a higher I2D/IG ratio (0.418) was observed at 1200°C, which implies that there are fewer graphene layers at this temperature. The lowest ID/IG ratio (0.908) for the graphene layers was obtained at 1200°C, suggesting that graphene had fewer defects at this temperature. The size of the graphene domains was also calculated. We found that by increasing the growth temperature, the graphene domain size also increased.
  • 7.

    Comparative electrochemical study of sulphonated polysulphone binded graphene oxide supercapacitor in two electrolytes

    Harish Mudila | M. G. H. Zaidi | Sweta Rana and 1other persons | 2016, 18() | pp.43~48 | number of Cited : 1
    Sulphonated polysulphone (SPS) has been synthesized and subsequently applied as binder for graphene oxide (GO)-based electrodes for development of electrochemical supercapacitors. Electrochemical performance of the electrode was investigated using cyclic voltammetry in 1M Na2SO4 and 1M KOH solution. The fabricated supercapacitors gave a specific capacitance of 161.6 and 216.8 F/g with 215.4 W/kg and 450 W/kg of power density, in 1M Na2SO4 and 1M KOH solutions, respectively. This suggests that KOH is a better electrolyte than Na2SO4 for studying the electrochemical behavior of electroactive material, and also suggests SPS is a good binder for fabrication of a GO based electrode.
  • 8.

    Cu2+ ion reduction in wastewater over RDF-derived char

    Hyung Won Lee | Rae-su Park | Sung Hoon Park and 6other persons | 2016, 18() | pp.49~55 | number of Cited : 5
    Refuse-derived fuel (RDF) produced using municipal solid waste was pyrolyzed to produce RDF char. For the first time, the RDF char was used to remove aqueous copper, a representative heavy metal water pollutant. Activation of the RDF char using steam and KOH treatments was performed to change the specific surface area, pore volume, and the metal cation quantity of the char. N2 sorption, Inductively Coupled Plasma-Atomic Emission Spectrometer (ICP-AES), and Fourier transform infrared spectroscopy were used to characterize the char. The optimum pH for copper removal was shown to be 5.5, and the steam-treated char displayed the best copper removal capability. Ion exchange between copper ions and alkali/alkaline metal cations was the most important mechanism of copper removal by RDF char, followed by adsorption on functional groups existing on the char surface. The copper adsorption behavior was represented well by a pseudo-second-order kinetics model and the Langmuir isotherm. The maximum copper removal capacity was determined to be 38.17 mg/g, which is larger than those of other low-cost char adsorbents reported previously.
  • 9.

    Cellulose-based carbon fibers prepared using electron-beam stabilization

    김민일 | 박미선 | Lee, Young-Seak | 2016, 18() | pp.56~61 | number of Cited : 1
    Cellulose fibers were stabilized by treatment with an electron-beam (E-beam). The properties of the stabilized fibers were analyzed by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The E-beam-stabilized cellulose fibers were carbonized in N2 gas at 800°C for 1 h, and their carbonization yields were measured. The structure of the cellulose fibers was determined to have changed to hemicellulose and cross-linked cellulose as a result of the E-beam stabilization. The hemicellulose decreased the initial decomposition temperature, and the cross-linked bonds increased the carbonization yield of the cellulose fibers. Increasing the absorbed E-beam dose to 1500 kGy increased the carbonization yield of the cellulose-based carbon fiber by 27.5% upon exposure compared to untreated cellulose fibers.
  • 10.

    Investigation of carbon dioxide adsorption by nitrogen-doped carbons synthesized from cubic MCM-48 mesoporous silica

    허영정 | Minh-Uyen T. Le | PARK SOOJIN | 2016, 18() | pp.62~66 | number of Cited : 5
    Carbon dioxide (CO2) is a component of the flue gas of power plants and automobile emissions. This gas is recognized as a primary greenhouse gas and is a presumed agent of climate change [1,2]. The drawbacks of the traditional MEA liquid method that is used for CO2 capture include the requirement for heavy equipment, and the toxic, flammable, corrosive, and volatile nature of the process [3]. Therefore, CO2 capture by means of adsorption in porous materials has received increasing attention because this method has proven to be superior than the conventional technologies in terms of the advantages associated with it. Compared to traditional processes, the convenient reversibility of adsorption on porous solid materials based on physisorption for the capture and release of CO2 makes this technique a greener and more cost-efficient method. To date, a variety of solid-based materials have been intensively studied for gas adsorption, especially CO2 capture, such as metal organic frameworks, covalent organic frameworks, zeolites, activated carbons, functionalized graphene, carbon molecular sieves, chemically modified mesoporous materials, etc [4-13].
  • 11.

    Enhancement of reflectance of densified vertically aligned carbon nanotube forests

    Masud Rana | MAsyraf MRazib | T. Saleh and 1other persons | 2016, 18() | pp.67~70 | number of Cited : 0
    Vertically aligned carbon nanotubes (VACNTs), also known as a carbon nanotube (CNT) forest, are a porous material that is well known for its exceptional optical absorbance property. The reflectance from a VACNT forest has been reported to be as low as 0.045% [1,2]. It is known as the darkest material on Earth. Because of its remarkable material properties, it has various other applications as gas sensors [3], pressure sensors [4], temperature sensors [5], and strain sensors [6]. Recently, various efforts have been made to mechanically manipulate the vertical structure of the nanotubes in the CNT forest and to conduct their optical characterization [7,8]. Optical reflection from bare VACNTs has also been investigated at different wavelengths by W?sik et al. [9]. Controlled densification by wetting of the CNT forest is another post processing technique that has been reported by other researchers [10]. A densification process is necessary to make the CNT forest useful as a future electronics interconnect [10]. However, no study has been done so far on the optical behavior of CNT forests densified by a wetting process. In this letter, for the first time, we investigate and explain the nature of the optical reflectance of densified VACNTs.
  • 12.

    Comparative study on various sponges as substrates for reduced graphene oxide-based supercapacitor

    Dongcheol Choi | Kyuwon Kim | 2016, 18() | pp.71~75 | number of Cited : 1
    To solve environmental problems and address the exhaustion of fossil fuel resources, the development of environmentally friendly and alternative energy storage devices has attracted much interest. Supercapacitors are attractive devices for such a purpose because of their high power density, long cycle life, low maintenance, wide range of operating temperatures, and fast charging time compared to conventional capacitors and batteries [1- 5]. Supercapacitors can be divided into two general classes characterized by their unique mechanism for storing charge. The first class includes electrochemical double layer capacitors (EDLCs), which store a charge electrostatically or non-faradically, when the charge is distributed over surfaces through physical processes. EDLCs generally operate with stable capacitive performance for many charge-discharge cycles because there are no chemical or compositional changes. The second class is called pseudocapacitors. These store a charge faradically through redox reactions and electrosorption at the surface of a suitable electrode. Pseudocapacitors can achieve greater energy densities than EDLCs [5-8].
  • 13.

    Pore structure control of activated carbon fiber for CO gas sensor electrode

    Byong Chol Bai | 배태성 | 2016, 18() | pp.76~79 | number of Cited : 4
    Materials with porous structures developed in previous research have been used extensively in industrial purification and chemical recovery operations due to their large specific surface areas and pore volumes. Among a wide range of activation methods, chemical activation is an effective and simple method to prepare activated carbons with a high specific surface area. Depending on the chemical agents used, chemical activation can lead to unique pore structures [1-3]. CO gas detection has recently become a critical issue because CO is one of the most common air pollutants. Pollutant CO gas is produced by incomplete hydrocarbon burning and accompanies almost all combustion processes. CO is especially dangerous because it possesses no odor or color and is therefore undetectable by humans. CO gas also becomes explosive at concentrations above 12% and has a threshold limit value of 25 ppm. Vehicle exhaust is a major source of environmental CO emissions and contributes to smog formation. Thus, the development of highly selective and stable CO sensors is an important goal and will assist in the study of environmental impacts. Motivated by the increasingly strict laws for different pollutant sources, recently there has been rapid progress in the fabrication of sensors to detect and monitor the environment, and several types of gas sensors have been reported in the literature [4-9].
  • 14.

    Structural and preliminary electrochemical characteristics of palm oil based carbon nanospheres as anode materials in lithium ion batteries

    Arenst Andreas Arie | Hans Kristianto | Ratna Frida Susanti and 3other persons | 2016, 18() | pp.80~83 | number of Cited : 0
    Since the invention of the lithium-ion battery (LIB) in the early 1990s by SONY, graphite carbon has been used as the anode material because of its low cost, chemical stability, and stable electrochemical performance [1]. The limitations of graphite anodes, especially related to their small energy and power output per unit mass or volume, are retarding the development of certain high-tech industries such as hybrid electric vehicles and stationary energy storage [2]. Therefore, there is currently an intense search for new anode materials for LIBs, with high specific capacity and energy density [3,4].
  • 15.

    High-performance asymmetric supercapacitors based on polyoxometalate-graphene nanohybrids

    MinHo Yang | Bong Gill Choi | 2016, 18() | pp.84~89 | number of Cited : 1
    Supercapacitors (SCs) have attracted much attention as energy storage devices capable of accumulating electricity from renewable sources, as well as deliver high power to smart and portable electronic devices due to their fast dynamic response, high power density, and long cycle-life [1,2]. So far, nanostructured electrodes with pseudocapacitive materials have been widely utilized to enhance the specific capacitance and energy density of supercapcitors [3,4]. However, such materials typically have low electrical conductivity (10?5~10?9 S cm?1) [5,6], degrade structurally under rigorous reaction conditions [7], and have a narrow electrochemical window (<1 V) [8,9] which can lead to high internal resistance, large irreversible capacitance loss, and poor rate capability and, consequently, result in supercapacitors with limited power density. A promising strategy to increase power density has been to extend operating cell voltage by taking advantage of an organic electrolyte, or an asymmetric cell configuration [10]. In terms of cost and safety, aqueous asymmetric supercapacitors (ASCs) are a suitable choice for commercial SCs [11]. Aqueous ASCs usually consist of a battery-type Faradic electrode for the energy source and a capacitor-type electrode for the power source, and employ aqueous electrolytes, which can increase cell voltage (up to 2 V) and hence improve both energy and power densities [11,12].