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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal DOI :
Korean Carbon Society
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Volume & Issues
Volume 15, Issue 4 - Oct 2014
Volume 15, Issue 3 - Jul 2014
Volume 15, Issue 2 - Apr 2014
Volume 15, Issue 1 - Jan 2014
Selecting the target year
Hierarchical porous carbon nanofibers via electrospinning
Raza, Aikifa ; Wang, Jiaqi ; Yang, Shan ; Si, Yang ; Ding, Bin ;
Carbon letters, volume 15, issue 1, 2014, Pages 1~14
DOI : 10.5714/CL.2014.15.1.001
Carbon nanofibers (CNFs) with diameters in the submicron and nanometer range exhibit high specific surface area, hierarchically porous structure, flexibility, and super strength which allow them to be used in the electrode materials of energy storage devices, and as hybrid-type filler in carbon fiber reinforced plastics and bone tissue scaffold. Unlike catalytic synthesis and other methods, electrospinning of various polymeric precursors followed by stabilization and carbonization has become a straightforward and convenient way to fabricate continuous CNFs. This paper is a comprehensive and brief review on the latest advances made in the development of electrospun CNFs with major focus on the promising applications accomplished by appropriately regulating the microstructural, mechanical, and electrical properties of as-spun CNFs. Additionally, the article describes the various strategies to make a variety of carbon CNFs for energy conversion and storage, catalysis, sensor, adsorption/separation, and biomedical applications. It is envisioned that electrospun CNFs will be the key materials of green science and technology through close collaborations with carbon fibers and carbon nanotubes.
Microwave heating of carbon-based solid materials
Kim, Teawon ; Lee, Jaegeun ; Lee, Kun-Hong ;
Carbon letters, volume 15, issue 1, 2014, Pages 15~24
DOI : 10.5714/CL.2014.15.1.015
As a part of the electromagnetic spectrum, microwaves heat materials fast and efficiently via direct energy transfer, while conventional heating methods rely on conduction and convection. To date, the use of microwave heating in the research of carbon-based materials has been mainly limited to liquid solutions. However, more rapid and efficient heating is possible in electron-rich solid materials, because the target materials absorb the energy of microwaves effectively and exclusively. Carbon-based solid materials are suitable for microwave-heating due to the delocalized pi electrons from sp2-hybridized carbon networks. In this perspective review, research on the microwave heating of carbon-based solid materials is extensively investigated. This review includes basic theories of microwave heating, and applications in carbon nanotubes, graphite and other carbon-based materials. Finally, priority issues are discussed for the advanced use of microwave heating, which have been poorly understood so far: heating mechanism, temperature control, and penetration depth.
Morphological optimization of process parameters of randomly oriented carbon/carbon composite
Raunija, Thakur Sudesh Kumar ; Manwatkar, Sushant Krunal ; Sharma, Sharad Chandra ; Verma, Anil ;
Carbon letters, volume 15, issue 1, 2014, Pages 25~31
DOI : 10.5714/CL.2014.15.1.025
A microstructure analysis is carried out to optimize the process parameters of a randomly oriented discrete length hybrid carbon fiber reinforced carbon matrix composite. The composite is fabricated by moulding of a slurry into a preform, followed by hot-pressing and carbonization. Heating rates of 0.1, 0.2, 0.3, 0.5, 1, and
and pressures of 5, 10, 15, and 20 MPa are applied during hot-pressing. Matrix precursor to reinforcement weight ratios of 70:30, 50:50, and 30:70 are also considered. A microstructure analysis of the carbon/carbon compacts is performed for each variant. Higher heating rates give bloated compacts whereas low heating rates give bloating-free, fine microstructure compacts. The compacts fabricated at higher pressure have displayed side oozing of molten pitch and discrete length carbon fibers. The microstructure of the compacts fabricated at low pressure shows a lack of densification. The compacts with low matrix precursor to reinforcement weight ratios have insufficient bonding agent to bind the reinforcement whereas the higher matrix precursor to reinforcement weight ratio results in a plaster-like structure. Based on the microstructure analysis, a heating rate of
, pressure of 15 MPa, and a matrix precursor to reinforcement ratio of 50:50 are found to be optimum w.r.t attaining bloating-free densification and processing time.
Mechanical and thermal properties of MWCNT-reinforced epoxy nanocomposites by vacuum assisted resin transfer molding
Lee, Si-Eun ; Cho, Seho ; Lee, Young-Seak ;
Carbon letters, volume 15, issue 1, 2014, Pages 32~37
DOI : 10.5714/CL.2014.15.1.032
Multi-walled carbon nanotube (MWCNT)/epoxy composites are prepared by a vacuum assisted resin transfer molding (VARTM) method. The mechanical properties, fracture surface morphologies, and thermal stabilities of these nanocomposites are evaluated for epoxy resins with various amounts of MWCNTs. Composites consisting of different amounts of MWCNTs displayed an increase of the work of adhesion between the MWCNTs and the matrix, which improved both the tensile and impact strengths of the composites. The tensile and impact strengths of the MWCNT/epoxy composite improved by 59 and 562% with 0.3 phr of MWCNTs, respectively, compared to the epoxy composite without MWCNTs. Thermal stability of the 0.3 phr MWCNT/epoxy composite increased compared to other epoxy composites with MWCNTs. The enhancement of the mechanical and thermal properties of the MWCNT/epoxy nanocomposites is attributed to improved dispersibility and strong interfacial interaction between the MWCNTs and the epoxy in the composites prepared by VARTM.
Preparation and application of reduced graphene oxide as the conductive material for capacitive deionization
Nugrahenny, Ayu Tyas Utami ; Kim, Jiyoung ; Kim, Sang-Kyung ; Peck, Dong-Hyun ; Yoon, Seong-Ho ; Jung, Doo-Hwan ;
Carbon letters, volume 15, issue 1, 2014, Pages 38~44
DOI : 10.5714/CL.2014.15.1.038
This paper reports the effect of adding reduced graphene oxide (RGO) as a conductive material to the composition of an electrode for capacitive deionization (CDI), a process to remove salt from water using ionic adsorption and desorption driven by external applied voltage. RGO can be synthesized in an inexpensive way by the reduction and exfoliation of GO, and removing the oxygen-containing groups and recovering a conjugated structure. GO powder can be obtained from the modification of Hummers method and reduced into RGO using a thermal method. The physical and electrochemical characteristics of RGO material were evaluated and its desalination performance was tested with a CDI unit cell with a potentiostat and conductivity meter, by varying the applied voltage and feed rate of the salt solution. The performance of RGO was compared to graphite as a conductive material in a CDI electrode. The result showed RGO can increase the capacitance, reduce the equivalent series resistance, and improve the electrosorption capacity of CDI electrode.
Study on effect of chemical impregnation on the surface and porous characteristics of activated carbon fabric prepared from viscose rayon
Bhati, Surendra ; Mahur, J.S. ; Dixit, Savita ; Chobey, O.N. ;
Carbon letters, volume 15, issue 1, 2014, Pages 45~49
DOI : 10.5714/CL.2014.15.1.045
In this study, synthetic viscose rayon fabric has been used for preparing activated carbon fabric (ACF), impregnated with different concentrations of
. The effect of
impregnation on the weight yield, surface area, pore volume, chemical composition and morphology of ACF were studied. Experimental results revealed that both Brunauer-Emmett-Teller surface area and micropore volume increased with increasing
concentration; however, the weight yield and microporosity (%) decreased. It was observed that samples impregnated at
(AC-70) give higher yield and higher microporosity as compared to
(AC-30). The average pore size of the ACF also gradually increases from 18.2 to 19 and 16.7 to
, respectively. The pore size distribution of ACF was also studied. It is also concluded that the final ACF strength is dependent on the concentration of impregnant.
Water and oxygen permeation through transparent ethylene vinyl alcohol/(graphene oxide) membranes
Kim, Hye Min ; Lee, Heon Sang ;
Carbon letters, volume 15, issue 1, 2014, Pages 50~56
DOI : 10.5714/CL.2014.15.1.050
We prepared ethylene vinyl alcohol (EVOH)/graphene oxide (GO) membranes by solution casting method. X-ray diffraction analysis showed that GOs were fully exfoliated in the EVOH/GO membrane. The glass transition temperatures of EVOH were increased by adding GOs into EVOH. The melting temperatures of EVOH/GO composites were decreased by adding GOs into EVOH, indicating that GOs may inhibit the crystallization of EVOH during non-isothermal crystallization. However, the equilibrium melting temperatures of EVOH were not changed by adding GOs into EVOH. The oxygen permeability of the EVOH/GO (0.3 wt%) film was reduced to 63% of that of pure EVOH film, with 84% light transmittance at 550 nm. The EVOH/GO membranes exhibited 100 times better (water vapor)/(oxygen) selectivity performance than pure EVOH membrane.
Preparation and characterization of microporous NaOH-activated carbons from hydrofluoric acid leached rice husk and its application for lead(II) adsorption
Hassan, A.F. ; Youssef, A.M. ;
Carbon letters, volume 15, issue 1, 2014, Pages 57~66
DOI : 10.5714/CL.2014.15.1.057
Three activated carbons (ACs) were prepared using NaOH (N) as an activating agent. Hydrofluoric acid pre-leached rice husk was used as a precursor. After leaching, the precursor was washed with distilled water, dried, crushed, and then sieved; a size fraction of 0.3-0.5 mm was selected for carbonization in the absence of air at
. The carbonization product (LC) was mixed with NaOH at ratios of 1:2, 1:3, and 1:4 (wt of LC: wt of NaOH) and the produced ACs after activation at
were designated NLC21, NLC31, and NLC41, respectively. Surface and textural properties were determined using nitrogen adsorption at
, scanning electron microscopy images, thermogravimetric analysis, and Fourier transform infrared spectra. These ACs were used as adsorbents for lead(II) from aqueous solutions. The effects of the textural properties and the chemistry of the carbon surfaces were investigated and the impact of the operation conditions on the capacity for lead(II) sorption was also considered. Modification of NLC41 with
gave two other adsorbents,
respectively. These two new samples exhibited the highest removal capacities for lead(II), i.e.117.5 and 128.2 mg/g, respectively. The adsorption data fitted the Langmuir isotherm and the kinetic adsorption followed pseudo-second order kinetics. The thermodynamic parameters have been determined and they indicated a spontaneous endothermic process.
Effect of chemically reduced graphene oxide on epoxy nanocomposites for flexural behaviors
Lee, Seul-Yi ; Chong, Mi-Hwa ; Park, Mira ; Kim, Hak-Yong ; Park, Soo-Jin ;
Carbon letters, volume 15, issue 1, 2014, Pages 67~70
DOI : 10.5714/CL.2014.15.1.067
In this work, nanocomposites of epoxy resin and chemically reduced graphene oxide (RGO) were prepared by thermal curing process. X-ray diffractions confirmed the microstructural properties of RGO. Differential scanning calorimetry was used to evaluate the curing behaviors of RGO/epoxy nanocomposites with different RGO loading amounts. We investigated the effect of RGO loading amounts on the mechanical properties of the epoxy nanocomposites. It was found that the presence of RGO improved both flexural strength and modulus of the epoxy nanocomposites till the RGO loading reached 0.4 wt%, and then decreased. The optimum loading achieved about 24.5 and 25.7% improvements, respectively, compared to the neat-epoxy composites. The observed mechanical reinforcement might be an enhancement of mechanical interlocking between the epoxy matrix and RGO due to the unique planar structures.
Effects of pore structures on electrochemical behaviors of polyacrylonitrile-based activated carbon nanofibers by carbon dioxide activation
Lee, Hye-Min ; Kim, Hong-Gun ; An, Kay-Hyeok ; Kim, Byung-Joo ;
Carbon letters, volume 15, issue 1, 2014, Pages 71~76
DOI : 10.5714/CL.2014.15.1.071
Activated carbon nanofibers (ACNF) were prepared from polyacrylonitrile (PAN)-based nanofibers using
activation methods with varying activation process times. The surface and structural characteristics of the ACNF were observed by scanning electron microscopy and X-ray diffraction, respectively.
adsorption isotherm characteristics at 77 K were confirmed by Brunauer-Emmett-Teller and Dubinin-Radushkevich equations. As experimental results, many holes or cavernous structures were found on the fiber surfaces after the
activation as confirmed by scanning electron microscopy analysis. Specific surface areas and pore volumes of the prepared ACNFs were enhanced within a range of 10 to 30 min of activation times. Performance of the porous PAN-based nanofibers as an electrode for electrical double layer capacitors was evaluated in terms of the activation conditions.