Development of longitudinal mesoscopic textures in mesophase pitch-based carbon fibers through heat treatment

Carbon ◽  
1999 ◽  
Vol 37 (2) ◽  
pp. 203-211 ◽  
Author(s):  
Yozo Korai ◽  
Seong-Hwa Hong ◽  
Isao Mochida
Keyword(s):  
Heat Treatment ◽  
Carbon Fibers ◽  
Mesophase Pitch

Structures and physical properties of carbon fibers from coal tar mesophase pitch

1987 ◽  
Vol 2 (6) ◽  
pp. 850-857 ◽  
Author(s):  
T. Hamada ◽  
T. Nishida ◽  
Y. Sajiki ◽  
M. Matsumoto ◽  
M. Endo
Keyword(s):  
Heat Treatment ◽  
Carbon Fibers ◽  
Coal Tar ◽  
Transverse Cross Section ◽  
Mesophase Pitch ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transverse Magnetoresistance ◽  
Heat Treated ◽  
Degree Of Graphitization

Carbon fibers having various types of structures were prepared by spinning coal tar mesophase pitch, followed by thermosetting and heat treatment at high temperature. Two kinds of spinning—spinning with stirring the pitch above a capillary and without stirring—have been tried to form pitch fibers from coal tar mesophase pitch. Carbon fibers obtained from mesophase pitch and spun without stirring have a radial transverse structure where the graphite layers are arranged radially in the transverse cross section of the fibers. Carbon fibers made with a stirring system can have random, onion, and a novel “quasionion structure” by changing the spinning conditions. Carbon fibers spun with stirring are less graphitizable than those spun without stirring. No separation of the ten diffraction bands into 100 and 101 peaks and no appearance of a 112 peak were observed by x-ray diffraction when the fibers were heat treated at 2700°C, whereas carbon fibers spun without stirring show clear evidence of graphitization by heat treatment at 2700°C. Transverse magnetoresistance effects at 77 K, (Δρ/ρ)t have been measured to characterize the structure of the carbon fibers. The carbon fibers spun with stirring and heat treated at 2500°C generally exhibit a negative transverse magnetoresistance effect, whereas the carbon fibers spun without stirring exhibit a positive magnetoresistance. Good correlations are found among d002, Lc (002), transverse magnetoresistance, and resistivity at room temperature of carbon fibers spun under various conditions and heat treated at 2500°C. The tensile strengths (TS) of carbon fibers that are less graphitized are higher than those of carbon fibers with a higher degree of graphitization if tensile moduli (TM) are almost constant.

scholarly journals Compositional Fibers Based on Coal Tar Mesophase Pitch Obtained by Electrospinning Method

2021 ◽  
Vol 15 (3) ◽  
pp. 403-407
Author(s):  
Aldan Imangazy ◽  
◽  
Gaukhar Smagulova ◽  
Bayan Kaidar ◽  
Zulkhair Mansurov ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Carbon Fibers ◽  
Coal Tar ◽  
Complete Removal ◽  
Mesophase Pitch ◽  
Coal Processing ◽  
Mesophase Formation ◽  
Electrospinning Method ◽  
Processing Wastes ◽  
Sulfur Containing

This research examines the use of coal-processing wastes of Shubarkol deposit (Kazakhstan) in obtaining useful materials such as carbon fibers. For our experiments, mesophase pitch was obtained by coal tar heat treatment at 773 K. Spinnable solution was prepared by crushing mesophase pitch into the pieces with adding poly(methylmethacrylate) as a fiber-forming material and 1,2-dichloroethane as a solvent. Elemental analysis revealed that the chemical composition of mesophase pitch (С – 91.48 %; О – 8.52 %; S – 0.00 %) showed that heat treatment up to 773 K leads to the complete removal of sulfur-containing components which affect the mesophase formation. Raman data of the obtained pitch revealed the appearance of D (1366 cm-1) and G (1605 cm-1) peaks, which are responsible for carbon materials; another peak at 2900 cm-1 shows the presence of C–H bonds. Carbon fibers with the diameter of 0.8–1.75 μm were obtained by electrospinning method in laboratory settings.

scholarly journals OBTAINING CARBON FIBERS BASED ON COAL TAR BY ELECTROSPINNING METHOD

2021 ◽  
Vol 73 (1) ◽  
pp. 151-159
Author(s):  
A.M. IMANGAZY ◽  
◽  
B. KAIDAR ◽  
Keyword(s):  
Heat Treatment ◽  
Carbon Fibers ◽  
Coal Tar ◽  
Average Diameter ◽  
Mesophase Pitch ◽  
Coal Processing ◽  
Electrospinning Technique ◽  
Electrospinning Method ◽  
Processing Wastes ◽  
Sulfur Containing

This research discusses the use of coal-processing wastes of the Shubarkol Deposit (Karaganda region, Kazakhstan) to produce valuable materials such as carbon fibers. Annually «Shubarkol Komir» JSC alone produces up to 35,000 tons of coal tar as byproduct. In this experiment, mesophase pitch was obtained by coal tar heat treatment at 200 o C. By cracking mesophase pitch into the pieces with the addition of poly (methyl methacrylate) as fiber-forming material and 1,2-dichloroethane as solvent, the spinnable solution was prepared. The elemental analysis of the mesophase pitch showed that the heat treatment up to 200 o C does not contribute to the full elimination of sulfur containing components that influence the forming of mesophase. From the Raman spectra of the pitch, the D peak appearance at ~ 1370 cm-1 and G peak at ~ 1600 cm-1 responsible for carbon products. Carbon fibers with an average diameter of 2.5-3.3 μm were obtained by electrospinning technique in laboratory settings.

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