Polyacrylonitrile based carbon fibers: Spinning technology dependent precursor fiber structure and its successive transformation

2021 ◽  
pp. 50988
Author(s):  
Jiaojiao Li ◽  
Yuxiu Yu ◽  
Haojie Li ◽  
Yaodong Liu
Keyword(s):  
Carbon Fibers ◽  
Precursor Fiber ◽  
Fiber Structure ◽  
Successive Transformation

scholarly journals Designing Materials and Processes for Strong Polyacrylonitrile Precursor Fibers

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2863
Author(s):  
Hyunchul Ahn ◽  
Sang Young Yeo ◽  
Byoung-Sun Lee
Keyword(s):  
Carbon Fibers ◽  
Material Properties ◽  
Mechanical Performance ◽  
Superior Performance ◽  
Materials Processing ◽  
Effective Strategy ◽  
Precursor Fiber ◽  
Polyacrylonitrile Precursor

Although polyacrylonitrile (PAN)-based carbon fibers have been successfully commercialized owing to their excellent material properties, their actual mechanical performance is still much lower than the theoretical values. Meanwhile, there is a growing demand for the use of superior carbon fibers. As such, many studies have been conducted to improve the mechanical performance of carbon fibers. Among the various approaches, designing a strong precursor fiber with a well-developed microstructure and morphology can constitute the most effective strategy to achieve superior performance. In this review, the efforts used to modulate materials, processing, and additives to deliver strong precursor fibers were thoroughly investigated. Our work demonstrates that the design of materials and processes is a fruitful pathway for the enhancement of the mechanical performance of carbon fibers.

Pitch-based carbon fibers as studied by transmission electron microscopy

1989 ◽  
Vol 4 (4) ◽  
pp. 1027-1033 ◽  
Author(s):  
T. Hamada ◽  
Y. Sajiki ◽  
M. Furuyama ◽  
T. Tomioka ◽  
M. Endo
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Carbon Fibers ◽  
Coal Tar ◽  
Preferred Orientation ◽  
Fiber Axis ◽  
Precursor Fiber ◽  
Transverse Fiber ◽  
Transmission Electron ◽  
Heat Treated

The microstructures of carbon fibers prepared from coal tar mesophase pitch and heat-treated at 2500 °C were studied by transmission electron microscopy (TEM). The degree of preferred orientation of the carbon fibers along the fiber axis was not significantly changed: by spinning, while stirring the pitch above the capillary; by changing the viscosity of the pitch in spinning from 60 poise to 250 poise, keeping the diameter of the pitch precursor fiber about 11.5 μm, which is that of the as-spun fiber; and by controlling the diameter of the pitch fiber from 8 μm to 18 μm, keeping the viscosity of the pitch at about 250 poise. Such a weak dependency of the degree of preferred orientation of the carbon fibers on the spinning conditions is qualitatively consistent with the relationships between the degree of preferred orientation of a pitch precursor fiber and the spinning conditions. The graphite layers of the carbon fibers heat-treated at 2500 °C showed shrinkage in the transverse fiber cross section. The degree of shrinkage was significantly increased by stirring the pitch above the capillary while spinning, and the shrinkage also increased when the viscosity of the pitch was increased for spinning, and when the diameter of the fibers was decreased. Roughly speaking, the degree of shrinkage was proportional to the mean size of the mesophase domains in the transverse section of pitch precursor fibers.

Preferred orientation of high performance carbon fibers

1992 ◽  
Vol 7 (9) ◽  
pp. 2612-2620 ◽  
Author(s):  
T. Hamada ◽  
M. Furuyama ◽  
T. Tomioka ◽  
M. Endo
Keyword(s):  
Heat Treatment ◽  
Carbon Fibers ◽  
High Performance ◽  
Preferred Orientation ◽  
Fiber Axis ◽  
Precursor Fiber ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Clear Peak

The preferred orientation of polyacrylnitrile (PAN)-based carbon fibers, mesophase pitch-derived carbon fibers, and pitch precursor fibers was studied by using x-ray diffraction technique. The half width at half maximum (HWHM) intensity of the φ scan x-ray diffraction profiles of these fibers was a minimum at around 2θ = 26°. The result implies that a crystallite with a larger coherence length of crystallite size Lc(002) is better aligned along the fiber axis than that with a smaller Lc(002) in these fibers. Further, θ-2θ scan profiles depending on φ showed that a better aligned crystallite possesses a larger Lc(002) than a misaligned one. Lc(002) of a significantly misoriented crystallite remained constant at about 2 nm even after heat-treatment, though Lc(002) of a well-aligned crystallite was easily changed by heat-treatment for both PAN and pitch-based fibers. The pitch precursor fiber exhibited a clear peak at about 2θ = 7° in the θ-2θ profile and unusual ° scan profiles for 2θ around 7°, which were explained by assuming columnar structures formed by molecule stacking along the c-axis with periodic arrangements of the columns perpendicular to the c-axis. The periodic column stacking structure observed in the pitch precursor fiber was also detected in pitch-based carbon fibers heat-treated at lower temperatures.

The Effect of Polyvinyl Pyrrolidone and Nickel Acetylacetonate on the Fabrication of Polyacrylonitrile Precursor Fiber

2014 ◽  
Vol 936 ◽  
pp. 905-910
Author(s):  
Zhi Hui Wang ◽  
Hai Qin Rong ◽  
Ao Yun Xu ◽  
Hui Min Lin ◽  
Shu Hui Zhao
Keyword(s):  
Carbon Fibers ◽  
Mesoporous Carbon ◽  
Polyvinyl Pyrrolidone ◽  
Benzene Adsorption ◽  
Ftir Analysis ◽  
Precursor Fiber ◽  
Mass Ratio ◽  
Nickel Acetylacetonate ◽  
Pan Fiber ◽  
Polyacrylonitrile Precursor

The effect of polyvinyl pyrrolidone (K30) and nickel acetylacetonate (Ni (acac)2) on the fabrication of polyacrylonitrile (PAN) fiber was investigated. K30 and Ni (acac)2 were chosen as pore-forming agents to prepare mesoporous carbon fibers.Meanwhile, the concentration of K30 and Ni (acac)2, the mass ratio of pore-forming agent to PAN, the rheological properties of spinning dope, the mechanical properties, thermal performance of fiber precursor were also characterized. Furthermore, the precursor fibers and the carbon fibers were researched by FTIR analysis, TG analysis and static benzene adsorption. Based on the research, when the concentration of K30 and Ni (acac)2 was 5%, the mass ratio of K30/Ni (acac)2 to PAN was 7:3, the fiber precursors had excellent properties. Adding poreforming agent, the pore distribution was controlled.

Effects of Stabilization Temperature on the Chemical and the Physical Properties of Polyacrylonitrile Stabilized Fibers

2015 ◽  
Vol 1112 ◽  
pp. 402-405
Author(s):  
Norhaniza Yusof ◽  
Ahmad Fauzi Ismail ◽  
Juhana Jaafar ◽  
W.N.W. Salleh ◽  
H. Hasbullah
Keyword(s):  
Tensile Strength ◽  
Physical Properties ◽  
Carbon Fibers ◽  
Chemical Structure ◽  
Young Modulus ◽  
Precursor Fiber ◽  
Stabilization Time ◽  
Ftir Studies ◽  
Stabilization Temperature ◽  
Mechanical Strengths

The present work dealt with the preparation of carbon fibers from Polyacrylonitrile (PAN)/ acrylamide (AM) fibers via a solvent-free coagulation process. The PAN/AM fibers were stabilized in an oxidizing atmosphere at various temperatures (200, 250, 275, and 300 °C), while the stabilization time was fixed at thirty minutes. The effects of stabilization temperature on the chemical and the physical properties of the prepared stabilized fibers were studied. The chemical structure evolutions of stabilized fibers (SFs) from the precursor fiber were observed with FTIR studies, whereas the microstructure properties were thoroughly characterized with SEM studies. The mechanical strengths of the SFs were obtained from the Young Modulus and the tensile strength analyses. Stabilization temperature at 275°C had been identified as the optimum stabilization temperature for the PAN/AM fibers.

Structures and electric properties of pitch-based carbon fibers heat-treated at various temperatures

1990 ◽  
Vol 5 (3) ◽  
pp. 570-577 ◽  
Author(s):  
T. Hamada ◽  
M. Furuyama ◽  
Y. Sajiki ◽  
T. Tomioka ◽  
M. Endo
Keyword(s):  
Carbon Fibers ◽  
Room Temperature ◽  
Transverse Section ◽  
Chemical Constituents ◽  
Precursor Fiber ◽  
Negative Region ◽  
Heat Treated ◽  
Universal Dependence ◽  
Mean Size ◽  
The Mean

Four kinds of pitch precursor fibers possessing different mean sizes of mesophase domains in their transverse sections, but having the same chemical constituents, were prepared by controlling only the spinning conditions. The fibers were thermoset and heat-treated at various temperatures from 600°C to 3300 °C. Lc (002) or d002 vs THT curves showed that pitch precursor fibers with finer transverse microstructures have a lower degree of graphitizability. Further, these four kinds of fibers exhibited systematically different d002 vs Lc (002) curves. The resistivity at room temperature is dependent on d002, being independent of the mean size of the mesophase domains in the transverse section of the pitch precursor fiber. The transverse magnetoresistance at 77 K and 10 kG, (Δρ/ρ)t, also showed a universal dependence on d002 if (Δρ/ρ)t was positive. However, the (Δρ/ρ)t vs d002 curves seemed to be slightly split in the negative region of (Δρ/ρ)t for each of the four kinds of fibers.

Raman Spectroscopy Studies on the Microstructure Evolution from Cellulose to Carbon Fiber

2014 ◽  
Vol 789 ◽  
pp. 157-162
Author(s):  
Gui Zhi Ren ◽  
Yong Ju Zang ◽  
Ning Wang ◽  
Li Hui Deng ◽  
Cong Jie Chen ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Raman Spectroscopy ◽  
Carbon Fiber ◽  
Carbon Fibers ◽  
Microstructure Evolution ◽  
Treatment Process ◽  
Treatment Temperature ◽  
Fiber Structure ◽  
Dry Process ◽  
Spectroscopy Studies

Microstructure evolution of cellulose-based carbon fibers during the heat-treatment process of pyrolysis and carbonization was studied by Raman spectroscopy. The characteristic peaks of cellulose fibers were weakened after a dry process at 100°C and absolutely disappeared after the pyrolysis temperature reached 150°C. For intermediates obtained in the temperature of 150-1300°C, two characteristic Raman peaks appeared at ~1360cm-1 and ~1580cm-1, meaning a transition state structure of carbon hexagonal plane started to form. Parameters including ID1’/IG’, ID2’/IG’ and ID3’/IG’ of the intermediates treated in the temperature of 150-1300°C were compared. All the parameters firstly decreased with the increasing heat treatment temperature until a maximum at ~400°C,and then the parameters decreased until the structure turned into a carbon fiber structure at 1300°C.

Preferred orientation of pitch precursor fibers and carbon fibers prepared from isotropic pitch

1992 ◽  
Vol 7 (5) ◽  
pp. 1178-1188 ◽  
Author(s):  
T. Hamada ◽  
M. Furuyama ◽  
T. Tomioka ◽  
M. Endo
Keyword(s):  
Carbon Fiber ◽  
Carbon Fibers ◽  
Preferred Orientation ◽  
Fiber Axis ◽  
Precursor Fiber ◽  
X Ray Diffraction ◽  
X Ray ◽  
Filament Diameter ◽  
Anisotropic Part ◽  
Isotropic Pitch

The preferred orientation of pitch precursor fibers and carbon fibers from an isotropic pitch was studied using x-ray diffraction techniques. The φ scan profile of a pitch precursor fiber was divided into two parts: φ scan-dependent (anisotropic) and φ scan-independent (isotropic) profiles. The half width at half maximum (HWHM) intensity of the anisotropic part became smaller as the pitch viscosity increased during spinning and as the filament diameter decreased. The area ratio of the anisotropic part to the total area increased when spinning at higher pitch viscosities and when making the diameter thinner; no preferred orientation existed for pitch precursor fibers with very large diameters. A thermodynamic model is proposed for the preferred orientation formation when spinning an isotropic pitch. The carbon fiber exhibited no skin-core difference in preferred orientation. A crystallite with a larger crystallite size Lc(002) in the carbon fiber was shown to be better aligned along the fiber axis than that with a smaller Lc(002). Furthermore, a well-aligned crystallite possessed a larger Lc(002) than one that was misaligned. The pitch precursor fiber also exhibited such a correlation between Lc(002) and the preferred orientation, but the correlation was weak.

EXELFS Studies of Carbon Fibers

1990 ◽  
Vol 48 (2) ◽  
pp. 72-73
Author(s):  
V. Serin ◽  
K. Hssein ◽  
G. Zanchi ◽  
J. Sévely
Keyword(s):  
Carbon Fibers ◽  
Energy Analysis ◽  
Electron Excitation ◽  
Complex Structures ◽  
High Modulus ◽  
Promising Technique ◽  
X Ray ◽  
Fine Structures ◽  
X Ray Absorption

The present developments of electron energy analysis in the microscopes by E.E.L.S. allow an accurate recording of the spectra and of their different complex structures associated with the inner shell electron excitation by the incident electrons (1). Among these structures, the Extended Energy Loss Fine Structures (EXELFS) are of particular interest. They are equivalent to the well known EXAFS oscillations in X-ray absorption spectroscopy. Due to the EELS characteristic, the Fourier analysis of EXELFS oscillations appears as a promising technique for the characterization of composite materials, the major constituents of which are low Z elements. Using EXELFS, we have developed a microstructural study of carbon fibers. This analysis concerns the carbon K edge, which appears in the spectra at 285 eV. The purpose of the paper is to compare the local short range order, determined by this way in the case of Courtauld HTS and P100 ex-polyacrylonitrile carbon fibers, which are high tensile strength (HTS) and high modulus (HM) fibers respectively.

Coating of continuous carbon fibers with double layers by chemical vapor deposition

2001 ◽  
Vol 11 (PR3) ◽  
pp. Pr3-885-Pr3-892 ◽  
Author(s):  
N. Popovska ◽  
S. Schmidt ◽  
E. Edelmann ◽  
V. K. Wunder ◽  
H. Gerhard ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Carbon Fibers ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Double Layers
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