scholarly journals Study on the Changes of Structures and Properties of PAN Fibers during the Cyclic Reaction in Supercritical Carbon Dioxide

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 402 ◽  
Author(s):  
Mengmeng Qiao ◽  
Haijuan Kong ◽  
Xiaoma Ding ◽  
Zhifeng Hu ◽  
Luwei Zhang ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Heating Temperature ◽  
Cyclization Reaction ◽  
Effect Of Temperature ◽  
High Heat Transfer ◽  
Structures And Properties ◽  
Ft Ir ◽  
Pan Fibers ◽  
Supercritical Carbon

Thermal pre-oxidation of polyacrylonitrile (PAN) fibers is a time-consuming and energy-consuming step in the production of PAN-based carbon fibers. In this paper, the effect of temperature on the structures and properties of PAN fibers cyclized in the supercritical carbon dioxide (Sc-CO2) medium was studied. The thermal behaviors of the PAN fibers were investigated by Fourier transform infrared spectra (FT-IR), X-ray diffraction (XRD), differential scanning calorimeter (DSC) and thermogravimetric analysis (TGA). The cyclization reaction was sensitive to the heating temperature and gas atmosphere. The FT-IR results of the PAN fibers treated in the Sc-CO2 confirmed that the degree of cyclization increased with the increase of the cyclization temperature. Compared with the PAN fibers treated in the air, the PAN fibers treated in the Sc-CO2 showed a higher degree of cyclization even at the same temperature. These findings might be related to the osmotic action of Sc-CO2 causing the fibers to be further arranged in a regular manner, which was favorable for the cyclization reaction. Moreover, as one kind of high diffusion and high heat transfer media, the heat release during the cyclization of PAN fibers could be quickly removed by Sc-CO2, which achieved the progress of the rapid-entry cyclization reaction.

Study on the Crystallization Behavior of PAN Fibers during Hot-Drawing Process in Supercritical Carbon Dioxide Fluid with Different Strain

2020 ◽  
Vol 976 ◽  
pp. 84-89
Author(s):  
Meng Meng Qiao ◽  
Hai Juan Kong ◽  
Xiao Ma Ding ◽  
Zhi Feng Hu ◽  
Mu Huo Yu
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Carbon Fibers ◽  
Crystallization Behavior ◽  
Strength Analysis ◽  
Drawing Process ◽  
Hot Drawing ◽  
Pan Fibers ◽  
Supercritical Carbon

Hot-drawing of polyacrylonitrile (PAN) fibers is an important step in the production of carbon fibers. In this article, we investigated the effect of strain on the crystallization behavior and mechanical properties of PAN fibers treated in supercritical carbon dioxide (Sc-CO2) fluid. We mainly used the methods of X-ray diffraction (XRD), monofilament strength analysis and differential scanning calorimeter (DSC) to study the crystallization behavior, mechanical properties and thermal behavior of PAN fibers during hot-drawing process. The experimental results showed that the crystallinity and mechanical properties of PAN fibers both increased a lot under the action of strain during hot-drawing in Sc-CO2 fluid. This provides an important method for preparation of higher performance PAN precursor for PAN-based carbon fibers.

FT-IR study on interactions between solutes and entrainers in supercritical carbon dioxide

2002 ◽  
Vol 193 (1-2) ◽  
pp. 203-216 ◽  
Author(s):  
Yoshio Iwai ◽  
Daisaku Tanabe ◽  
Morio Yamamoto ◽  
Taro Nakajima ◽  
Machiko Uno ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Ft Ir ◽  
Ir Study ◽  
Supercritical Carbon

scholarly journals Effect of Temperature and Pressure on Surface Tension of Polystyrene in Supercritical Carbon Dioxide

2007 ◽  
Vol 111 (15) ◽  
pp. 3859-3868 ◽  
Author(s):  
H. Park ◽  
R. B. Thompson ◽  
N. Lanson ◽  
C. Tzoganakis ◽  
C. B. Park ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Surface Tension ◽  
Supercritical Carbon Dioxide ◽  
Effect Of Temperature ◽  
Temperature And Pressure ◽  
Supercritical Carbon

scholarly journals Effect of Different Pressures of Supercritical Carbon Dioxide on the Microstructure of PAN Fibers during the Hot-Drawing Process

Polymers ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 403 ◽  
Author(s):  
Mengmeng Qiao ◽  
Haijuan Kong ◽  
Xiaoma Ding ◽  
Zhifeng Hu ◽  
Luwei Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Carbon Dioxide ◽  
Supercritical Carbon Dioxide ◽  
Strength Analysis ◽  
Drawing Process ◽  
X Ray ◽  
Degree Of Orientation ◽  
Hot Drawing ◽  
Pan Fibers ◽  
Supercritical Carbon

The hot-drawing process of polyacrylonitrile (PAN) fibers is an important step during the production of PAN-based carbon fibers. In this study, supercritical carbon dioxide (Sc-CO2) was used as one kind of media for thermal stretching of PAN fibers to study the effect of different pressures of Sc-CO2 on crystallinity, degree of orientation and mechanical property of PAN fibers during the hot-drawing process. The changes of microstructure and mechanical properties in the PAN fibers were investigated by wide-angle X-ray diffraction, small angle X-ray scattering and monofilament strength analysis. The results showed that as the pressure increased, the crystallinity and degree of orientation of PAN fibers increased. Furthermore, when the pressure was 10 MPa, the crystallinity increased from 69.78% to 79.99%, which was the maximum crystallinity among the different pressures. However, when the pressure was further increased, the crystallinity and degree of orientation of the fibers were reduced. The test results of the mechanical properties were consistent with the trends of crystallinity and degree of orientation, showing that when the pressure was 10 MPa, the tensile strength of the fibers increased from 4.59 cN·dtex−1 to 7.06 cN·dtex−1 and the modulus increased from 101.54 cN·dtex−1 to 129.55 cN·dtex−1.

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