Effect of precursor composition on the activation of pitchbased carbon fibers

Basova, Yulia V.; Edie, D.D.; Lee, Young-Seak; Reid, Laura K; Ryu, Seung‐Kon

doi:10.1016/j.carbon.2003.12.070

Cited by 25 publications

(10 citation statements)

References 13 publications

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“…Each sample had different characteristics depending on the concentration of H 3 PO 4 used. Generally, an increase in the isotherm curve indicates the development of a micropore structure (at less than 0.01 P/P 0 ) and a mesopore structure (above 0.01 P/P 0 ) [16,17]. Significant changes were observed above 0.1 P/P 0 in all other cases indicating that both mesopores and macropores developed.…”

Section: Textural Properties and Pore Structurementioning

confidence: 97%

Improved Sensitivity of an NO Gas Sensor by Chemical Activation of Electrospun Carbon Fibers

Kang¹,

Sun²,

Lee

2011

Carbon letters

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A novel electrode for an NO gas sensor was fabricated from electrospun polyacrylonitrile fibers by thermal treatment to obtain carbon fibers followed by chemical activation to enhance the activity of gas adsorption sites. The activation process improved the porous structure, increasing the specific surface area and allowing for efficient gas adsorption. The gas sensing ability and response time were improved by the increased surface area and micropore fraction. High performance gas sensing was then demonstrated by following a proposed mechanism based on the activation effects. Initially, the pore structure developed by activation significantly increased the amount of adsorbed gas, as shown by the high sensitivity of the gas sensor. Additionally, the increased micropore fraction enabled a rapid sensor response time due to improve the adsorption speed. Overall, the sensitivity for NO gas was improved approximately six-fold, and the response time was reduced by approximately 83% due to the effects of chemical activation.

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Section: Textural Properties and Pore Structurementioning

confidence: 97%

Improved Sensitivity of an NO Gas Sensor by Chemical Activation of Electrospun Carbon Fibers

Kang¹,

Sun²,

Lee

2011

Carbon letters

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“…Spinning yield and fiber diameter were affected by molecular composition of precursor pitch and by the spinning conditions such as spinning temperature, pressure, and winding speed [8][9][10]. In general, precursor pitch with broad molecular weight distribution raised the spinning temperature, while narrow molecular weight distribution improved the spinnability [3].…”

Section: Introductionmentioning

confidence: 98%

Characterization of differently shaped carbon fiber composites prepared from naphtha cracking bottom oil

Eom

Pyo

Ryu

2010

Korean J. Chem. Eng.

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Different shaped carbon fibers (R-, I-, C-, Y-, and X-type) were prepared from melt-spinning of reformed naphtha cracking bottom oil precursors through various shaped spinnerets. These different shaped CFs (carbon fibers) and PVC (polyvinyl chloride) resin were compounded, and then CF/PVC composites were prepared. Precursor pitch, carbon fibers, and composites were characterized and their properties were compared. Mechanical properties of carbon fibers and composites were characterized relating to external surface area and ratio of perimeter to cross-sectional area of carbon fibers. The tensile strength of tetralobal fibers (X-type) showed five times higher than that of round-shaped fibers (R-type) due to extended external surface area. Their tensile strength of CF/PVC composite increased as ratio of perimeter to cross-sectional area of carbon fibers. The magnitude of the ratio was in order to X-, C-, I-, Y-, and R-type.

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“…For example, when higher MW fractions are isolated from pitch, the large plate-like molecules can spontaneously align to form discotic liquid crystals (also called mesophase) that are the starting materials for high-thermal-conductivity carbon fibers [4]. On the other hand, other lower MW cuts are preferred as starting materials for the matrix phase of carboncarbon composites or for activated carbon fibers [5]. Unfortunately, the problem of determining fundamental molecular information for pitches is a difficult one that has yet to be solved.…”

Section: Introductionmentioning

confidence: 99%

Dense-gas fractionation of mixtures of petroleum macromolecules

Edwards

Thies

2005

Fluid Phase Equilibria

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Dense-gas extraction (DGE) was used to fractionate a petroleum pitch feedstock of broad molecular weight distribution (MWD) into selected oligomeric constituents. The DGE process was carried out in a semibatch mode using the solvent toluene (T c = 318.6 • C, P c = 41.1 bar) and a pitch charge of 10-15 g. A packed column with reflux produced the equivalent of several equilibrium stages. The apparatus was operated at near and supercritical temperatures, with the stillpot at 320 • C and the column temperature increasing linearly up to the reflux condenser temperature of 360 • C. Operating pressures were determined by the conditions required to extract a given oligomer and varied from 44 to 84 bar. Using a monomer-rich petroleum pitch feed (MW n = 299, PDI = 1.10), a dimer-rich extract with a purity approaching 90% (MW n = 521, PDI = 1.07) was obtained, with the remaining residue (MW n = 883, PDI = 1.24) consisting of 95% trimer and higher oligomers. MALDI-TOF mass spectrometry was used to determine the MWD of the feed pitch and pitch fractions, with a unique matrix being used to enhance the response of higher MW species. The combination of DGE for separation and MALDI for accurate MW information is a powerful new technique for the molecular characterization of insoluble, high MW fossil fuels.

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Effect of precursor composition on the activation of pitchbased carbon fibers

Cited by 25 publications

References 13 publications

Improved Sensitivity of an NO Gas Sensor by Chemical Activation of Electrospun Carbon Fibers

Improved Sensitivity of an NO Gas Sensor by Chemical Activation of Electrospun Carbon Fibers

Characterization of differently shaped carbon fiber composites prepared from naphtha cracking bottom oil

Dense-gas fractionation of mixtures of petroleum macromolecules

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