scholarly journals PRODUCTION OF CARBON NANOFIBERS BASED ON COAL TAR AND POLYACRYONITRILE BY ELECTROSPINNING METHOD

2021 ◽  
Vol 2 (446) ◽  
pp. 72-80
Author(s):  
B.T. Yermagambet ◽  
M.K. Kazankapova ◽  
A.T. Nauryzbayeva ◽  
Zh.M. Kassenova
Keyword(s):  
Room Temperature ◽  
Coal Tar ◽  
X Ray ◽  
Graphitized Carbon ◽  
Laboratory Setup ◽  
Electrospinning Method ◽  
Graphite Structure ◽  
Disordered Carbon ◽  
Oxidation In Air ◽  
Degree Of Graphitization

The article presents experiments on obtaining composite fibers based on Shubarkol coal tar (CT) and polycarlonitrile (PAN) by electrospinning in a laboratory setup. As a result of energy dispersive X-ray spectroscopy and SEM microscopy, the elemental composition (C-85.83%) and the diameter of the carbon fiber were determined, which ranged from 89.0 nm to 449.8 nm. The resulting CNF was subjected to oxidation in air at 300 °C, the holding time was 1 hour, after which the carbonization process was carried out at 800 °C, followed by cooling to room temperature. Raman spectra were recorded to study the degree of graphitization. The results of Raman scattering of light (RS) showed the degree of graphitization - 15.98%. Ratio I (D) / I (G) = 0.99, I (G) / I (D) = 1. The broad bands D (disordered part) and G (ordered graphite structure) suggest that CNFs contain partially graphitized carbon along with amorphous carbon. The ID / IG ratio represents the conversion of disordered carbon to graphite carbon during carbonization. The resistance of this material is 70-200 ohms. The results obtained confirm the semiconductor nature of the conductivity. On the basis of SEM drawings of CNFs from CT and PAN, it was found that the structure of CNFs after oxidation and carbonization retains the original fibrous structure. It was also found that the diameter of nanofibers decreases from 320.5 - 625.7 nm to 89-449.8 nm. Thus, the proposed method of obtaining CNF is built on the basis of the electrospinning method, which is the most promising method of industrial production.

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 SYNTHESIS OF CARBON NANOFIBERS BASED ON HUMIC ACID AND POLYACRYONITRILE BY ELECTROSPINNING METHOD

2021 ◽  
Vol 447 (3) ◽  
pp. 103-110
Author(s):  
B.T. Yermagambet ◽  
M.K. Kazankapova ◽  
A.T. Nauryzbayeva ◽  
Zh.M. Kassenova
Keyword(s):  
Electron Microscopy ◽  
Humic Acid ◽  
Elemental Composition ◽  
Carbon Nanofibers ◽  
Carbon Fibers ◽  
X Ray ◽  
Electrospinning Method ◽  
Original Product ◽  
Degree Of Graphitization ◽  
Scanning Electron

The article describes a method for obtaining carbon nanofibers (CNFs) based on humic acid from oxidized coal of the Maikuben basin and polycarlonitrile (PAN) by electrospinning in laboratory conditions. The value of the interelectrode voltage was 20-25 kV. The elemental composition was determined and the surface morphology of the studied sample was studied, the type of modification of the carbon fiber was revealed. As a result of energy dispersive X-ray spectroscopy and scanning electron microscopy (SEM), the chemical composition of the initial CNF (C-48.73%) and the diameter of carbon fibers, which ranged from 148.6 nm to 1.36 μm, were found. The processes of oxidation and carbonization of the obtained samples were also carried out. The elemental composition of carbon after oxidation and carbonization was 87.75 and 89.16%, respectively, the diameter of the fibers was 117.5 nm -1.03 microns. The results of Raman scattering of light (RS) of carbonized CNF showed the degree of graphitization - 23.97%, the ratio I (D) / I (G) = 0.7, I (G) / I (D) = 1.4. The resistance of this material was 27 ohms. On the basis of SEM patterns of CNFs based on humic acid and PAN, it was found that the structure of the sample after oxidation and carbonization retains the original fibrous structure. It was also found that the diameter of nanofibers decreases from 1 μm to 117.5 nm, which may be associated with the release of volatile and heterogeneous components of the original product and the formation of a more structural thin porous filament.

scholarly journals SYNTHESIS OF NANOCOMPOSITE FIBERS BASED ON ROCK PITCH AND NANOIRON BY ELECTROSPINNING

REPORTS ◽  
2020 ◽  
Vol 5 (333) ◽  
pp. 19-26
Author(s):  
B.T. Yermagambet ◽  
◽  
M.K. Kazankapova ◽  
Zh.M. Kassenova ◽  
A.T. Nauryzbayeva ◽  
...  
Keyword(s):  
Elemental Composition ◽  
Carbon Nanofiber ◽  
Coal Tar ◽  
Test Sample ◽  
Coal Tar Pitch ◽  
Chemical Bonds ◽  
X Ray ◽  
Laboratory Setup ◽  
Nanocomposite Fibers ◽  
Sample Structure

The article presents experiments on the production of nanocomposite fibers based on the Shubarkol coal tar pitch and nano-iron by the method of electrospinning in a laboratory setup. The elemental composition was determined and the surface morphology of the test sample was studied. As a result of energy dispersive X-ray spectroscopy and SEM microscopy, the elemental composition was determined: C-92.14%, O-6.16%, Al-0.30%, Si-0.26%, P-0.07%, S -0.20%, Cl -0.40%, Fe-0.47% and the diameter of the carbon nanofiber, which ranged from 94.2 nm to 800.0 nm. The results of IR spectroscopy showed an increase in the intensity of the peaks in the region of 2920-2850 cm-1 and the appearance of a signal at 2359 cm-1, which is explained by the breaking of several chemical bonds in the sample structure and the formation of a composite with nano-iron.

Structural and Ferromagnetic Properties SnO2/TiO2 Nanotubes Obtained by Electrospinning

NANO ◽  
2017 ◽  
Vol 12 (10) ◽  
pp. 1750127 ◽  
Author(s):  
Jian-Guo Zhao ◽  
Yan-Hong Gu ◽  
Hong Jia ◽  
Zhuan Hu ◽  
Shuqian Qiao ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Room Temperature ◽  
Room Temperature Ferromagnetism ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Electrospinning Method ◽  
Inner Diameter ◽  
Superconducting Quantum Interferometer

SnO2/TiO2 (Sn/Ti [Formula: see text]/1) nanotubes were prepared by the electrospinning method. The morphology was characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the inner diameter of prepared materials was about 100[Formula: see text]nm and the wall thickness was about 10[Formula: see text]nm. The results of X-ray diffraction (XRD) and high-resolution transmission electron microscope (HRTEM) showed that SnO2/TiO2 nanotubes had a mixed phase of SnO2 rutile and TiO2 anatase structures and no impurity phases. The magnetic properties of the SnO2/TiO2 nanotubes were characterized by a superconducting quantum interferometer (SQUID). The results indicated that the samples exhibited room temperature ferromagnetism which may be attributed to the interface between TiO2 and SnO2 phases.

ROOM-TEMPERATURE FERROMAGNETISM IN SnO2 NANOFIBERS AND NANOTUBES PREPARED BY ELECTROSPINNING

NANO ◽  
2014 ◽  
Vol 09 (02) ◽  
pp. 1450026 ◽  
Author(s):  
JIAN-GUO ZHAO ◽  
WEI-YING ZHANG ◽  
ER-QING XIE ◽  
XIU-YUN AN ◽  
JIE-CAI FU ◽  
...  
Keyword(s):  
Room Temperature ◽  
Oxygen Vacancies ◽  
Room Temperature Ferromagnetism ◽  
Magnetization Measurement ◽  
Zero Field ◽  
X Ray Diffraction ◽  
Rutile Structure ◽  
X Ray ◽  
Selected Area Electron Diffraction ◽  
Electrospinning Method

SnO 2 nanofibers and nanotubes were synthesized by electrospinning method. Magnetization measurement indicates that the SnO 2 nanofibers and nanotubes annealed in air at 500°C exhibit the room-temperature ferromagnetism and the ferromagnetism of nanotubes is stronger than the nanofibers. Selected area electron diffraction, X-ray diffraction and Raman measurements show that all the samples possess a typical rutile structure and no other impurity phases are observed. The results of the Raman spectra also indicate that there are lots of defects existing in the fabricated samples. The observed room-temperature ferromagnetism in SnO 2 nanofibers and nanotubes possibly originates from oxygen vacancies. The field cooled (FC) and zero-field-cooled (ZFC) magnetization curves indicate that the Curie temperature TC is above 300 K.

Direct Observation of Crystalline Ordering In Naturally Graphitized Carbon Produced by Low Grade Metamorphism

1977 ◽  
Vol 35 ◽  
pp. 162-163
Author(s):  
Thomas R. McKee ◽  
Peter R. Buseck
Keyword(s):  
Crystallite Size ◽  
Sedimentary Rocks ◽  
Carbonaceous Material ◽  
Low Grade ◽  
X Ray ◽  
Graphitized Carbon ◽  
Transmission Electron ◽  
Heat Treated ◽  
Commercial Carbon ◽  
Metamorphic Zone

Sediments commonly contain organic material which appears as refractory carbonaceous material in metamorphosed sedimentary rocks. Grew and others have shown that relative carbon content, crystallite size, X-ray crystallinity and development of well-ordered graphite crystal structure of the carbonaceous material increases with increasing metamorphic grade. The graphitization process is irreversible and appears to be continous from the amorphous to the completely graphitized stage. The most dramatic chemical and crystallographic changes take place within the chlorite metamorphic zone.The detailed X-ray investigation of crystallite size and crystalline ordering is complex and can best be investigated by other means such as high resolution transmission electron microscopy (HRTEM). The natural graphitization series is similar to that for heat-treated commercial carbon blacks, which have been successfully studied by HRTEM (Ban and others).

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

Opening images of synaptic vesicles and calcium localization by means of microwave fixation method

1990 ◽  
Vol 48 (2) ◽  
pp. 182-183
Author(s):  
Vinci Mizuhira ◽  
Hiroshi Hasegawa
Keyword(s):  
Synaptic Vesicles ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Sampling Procedure ◽  
Fixation Method ◽  
Potassium Oxalate ◽  
X Ray ◽  
Cacodylate Buffer ◽  
Ultrathin Sections ◽  
Microwave Fixation

Microwave irradiation (MWI) was applied to 0.3 to 1 cm3 blocks of rat central nervous system at 2.45 GHz/500W for about 20 sec in a fixative, at room temperature. Fixative composed of 2% paraformaldehyde, 0.5% glutaraldehyde in 0.1 M cacodylate buffer at pH 7.4, also contained 2 mM of CaCl2 , 1 mM of MgCl2, and 0.1% of tannic acid for conventional observation; and fuether 30-90 mM of potassium oxalate containing fixative was applied for the detection of calcium ion localization in cells. Tissue blocks were left in the same fixative for 30 to 180 min after MWI at room temperature, then proceeded to the sampling procedure, after postfixed with osmium tetroxide, embedded in Epon. Ultrathin sections were double stained with an useal manner. Oxalate treated sections were devided in two, stained and unstained one. The later oxalate treated unstained sections were analyzed with electron probe X-ray microanalyzer, the EDAX-PU-9800, at 40 KV accelerating voltage for 100 to 200 sec with point or selected area analyzing methods.

Evidence for ordered Fe3Ni

1987 ◽  
Vol 45 ◽  
pp. 216-217
Author(s):  
K.B. Reuter ◽  
D.B. Williams ◽  
J.I. Goldstein
Keyword(s):  
Experimental Data ◽  
Martensitic Transformation ◽  
Electron Diffraction ◽  
Room Temperature ◽  
Direct Evidence ◽  
Transformation Product ◽  
Iron Meteorites ◽  
X Ray ◽  
Ni Content ◽  
Temperature Transformation

In the Fe-Ni system, although ordered FeNi and ordered Ni3Fe are experimentally well established, direct evidence for ordered Fe3Ni is unconvincing. Little experimental data for Fe3Ni exists because diffusion is sluggish at temperatures below 400°C and because alloys containing less than 29 wt% Ni undergo a martensitic transformation at room temperature. Fe-Ni phases in iron meteorites were examined in this study because iron meteorites have cooled at slow rates of about 10°C/106 years, allowing phase transformations below 400°C to occur. One low temperature transformation product, called clear taenite 2 (CT2), was of particular interest because it contains less than 30 wtZ Ni and is not martensitic. Because CT2 is only a few microns in size, the structure and Ni content were determined through electron diffraction and x-ray microanalysis. A Philips EM400T operated at 120 kV, equipped with a Tracor Northern 2000 multichannel analyzer, was used.

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

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