Preparation of isotropic pitch-based carbon fiber using hyper coal through co-carbonation with ethylene bottom oil

Jianxiao Yang,Koji Nakabayashi,Jin Miyawaki,윤승호 한국공업화학회 2016 Journal of Industrial and Engineering Chemistry Vol.34 No.-

A spinnable pitch was developed from the tetrahydrofuran-soluble fractions (THFS) of hyper coal (HPC)and used to prepare carbon fibers. THFS-derived pitch from bituminous coal-derived HPC showedexcellent spinnability and the obtained carbon fibers had a tensile strength of over 800 MPa with adiameter of 13 mm following heat treatment at 800 8C for 5 min. Thus, HPC was shown to be a usefulalternative precursor for the preparation of low-cost and general-performance carbon fibers.

Preparation of isotropic spinnable pitch and carbon fiber from biomass tar through the co-carbonization with ethylene bottom oil

Jianxiao Yang,Kui Shi,Xuanke Li,Seong-Ho Yoon 한국탄소학회 2018 Carbon Letters Vol.25 No.-

In this study, we tried to prepare an isotropic spinnable pitch which can be useful to prepare the general purpose carbon fiber through the co-carbonization of biomass tar with ethylene bottom oil under two different preparation methods (atmospheric distillation, pressurized distillation). The results showed that the ethylene bottom oil added co-carbonization was very effective to decrease of the oxygen contents for obtaining a stable spinnable pitch. The pressurized distillation was more effective to reduce the oxygen functional groups of pitches than atmospheric distillation. The obtained spinnable pitch by the pressurized distillation showed higher pitch yield of 42% and lower oxygen content of 9.12% than the spinnable pitch by the atmospheric distillation. The carbon fiber derived from the pressurized distillation spinnable pitch by carbonization at 800ºC for 5 min showed that the higher tensile strength of carbon fiber was increased up to 800 MPa.

Facile preparation of oxygen-rich activated carbon from petroleum coke for enhancing methylene blue adsorption

Wu Wei,Zhang Xiaxiang,Yang Jianxiao,Lijun Cai,Li Xuanke 한국탄소학회 2020 Carbon Letters Vol.30 No.6

The oxygen-rich activated carbon (AC) was facilely developed using petroleum coke as a raw material by KOH activa�tion under the rapid heating rate. The porosity and surface chemistry of ACs prepared under diferent heating rates were characterized and their adsorption properties for methylene blue (MB) were investigated. The results showed that the AC5 prepared under the heating rate of 5 °C min−1 had the highest surface area compared with the AC10, AC15 or AC20, while the AC20 prepared under the heating rate of 20 °C min−1 consisted of the highest oxygen content and most –OH functional group compares with the other ACs. These indicated that rapid heating rate was against the formation of more developed porosity, however, it was benefcial to producing more oxygen functional groups. As to MB adsorption, AC15 exhibited the maximum adsorption capacity for MB of 884 mg g−1 due to high surface area of 2803 m2 g−1 and high oxygen content of 23.27%. Moreover, despite the fact that AC20 had much lower surface area than the AC5, the AC20 showed higher MB adsorption capacity than the AC5. This was because the AC20 has the highest content of –OH, which was a positive impetus for MB adsorption. Therefore, rapid heating rate was an efective and simple approach to preparing the oxygen-rich ACs for improving the adsorption capacity of MB.

Effect of anion species on preparation and properties of pitch-based activated carbon fibers by in-situ catalytic activation of metal nanoparticles

Gou Genchang,Wei Wenjie,Yang Jianxiao,Liu Jiahao,Liu Yue,Li Jun,Shi Kui 한국탄소학회 2022 Carbon Letters Vol.32 No.6

The pitch-based activated carbon fibers (ACFs) were prepared from ethylene tar-derived pitches containing nickelocene (CNi) or nickel nitrate (NiN). The effects of different anions and contents of metal salts on the microstructure and surface chemical properties of fibers were investigated. The results revealed that Ni2+ from CNi mainly remained its pristine molecule in the organometal salt-derived pitch (OP-xCNi), while Ni2+ from NiN occurred complexation reaction with polycyclic aromatic hydrocarbons (PAHs) in the inorganic metal salt-derived pitch (IP-xNiN) due to the weaker binding ability between anions and Ni2+ of CNi than CNi. The XRD and SEM results confirmed that IP-3NiN-ACF contained Ni, NiO, Ni2O3 nanoparticles with different size distributions, while OP-3CNi-ACF only contained more uniformly distributed Ni nanoparticles with small size. Furthermore, OP-3.0CNi-ACF presented higher specific surface area of 1862 m2/g and a pore volume of 1.69 cm3/g than those of IP-3.0NiN-ACF due to the formation of pore structure during the in-situ catalytic activation of different metal nanoparticles. Therefore, this work further pointed out that the desired pore structure and surface chemistry of pitch-based ACFs could be obtained through regulating and controlling the interaction of anion species, metal cations and PAHs during the synthesis of pitch precursors.

Preparation of Copper-coated Mesophase Pitch-based Carbon Fibers by Electroless Plating Technique with the APTES Grafting Modification

Jiangfan Shi,Yize Liu,Jianxiao Yang,Jun Li,Chong Ye,Dong Huang,Jinshui Liu,Xuanke Li 한국섬유공학회 2020 Fibers and polymers Vol.21 No.8

An upgrade synthesis method of electroless copper plating was developed to prepare the copper-coated mesophasepitch-based carbon fibers (Cu@CF) with APTES (3-Aminopropyl triethoxysilane) grafting modification. The microstructureand properties of the fibers which were prepared by the APTES sensitization method were investigated and compared withthose prepared by the conventional SnCl2 sensitization method. The results showed that as-coated fibers sensitized by APTESdemonstrated to have better interfacial cohesion between the copper layer and the fiber surface than those sensitized by SnCl2did. Moreover, the resistivity of Cu@CF-APTES declined to 2.3±0.9 μΩ·cm, while that of Cu@CF-SnCl2 was 9.3±3.7μΩ·cm. Besides, not only the strength of Cu@CF-APTES increased, but the strength discreteness of them reduced due to thefact that no peeling phenomenon was observed between the copper layer and fiber during the stretch test.

Numerical Analysis on Buffeting Performance of a Long-Span Four-Tower Suspension Bridge Using the FEM Model

Hao Wang,Zidong Xu,Min Yang,Tianyou Tao,Jianxiao Mao,Hui Gao 대한토목학회 2021 KSCE JOURNAL OF CIVIL ENGINEERING Vol.25 No.3

The multi-tower suspension bridge (MTSB), which is a considerable choice for the cross-river and even cross-sea bridges, has attracted intensive attentions by researchers in recent years. However, the static and dynamic performance of the MTSB becomes more complicated due to its super long spans and the multiple middle towers. The wind-induced vibration becomes the critical issue when constructs the MTSBs due to their low rigidity. In this work, a finite element model (FEM) of a MTSB with four towers and three spans is presented. Several major parameters such as the stiffness of the main girder and the middle towers, the sag-to-span ratios, the self-excited forces, and the spectral model of turbulence are selected to investigate their effects on buffeting performance of the MTSB. Results show that the rigid main girder can decrease the buffeting displacements in lateral and torsional directions, while the vertical buffeting displacement significantly decreases with the increasing stiffness of middle towers. In addition, the buffeting displacements of the main girder increase with the decreasing sag-to-span ratio. Besides, it can be concluded that the self-excited forces should be considered and the turbulent power spectrum should be carefully chosen in analyzing buffeting responses of the MTSB.

The microstructures and mechanical properties of ultra‑high‑strength PAN‑based carbon fibers during graphitization under a constant stretching

Chong Ye,Huang Wu,Dong Huang,Baoliu Li,Ke Shen,Jianxiao Yang,Jinshui Liu,Xuanke Li 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Commercial ultra-high-strength PAN-based carbon fibers (T1000G) were heat-treated at the temperature range of 2300– 2600 °C under a constant stretching of 600 cN. After continuous high-temperature graphitization treatment, microstructures, mechanical properties and thermal stability of the carbon fibers were investigated. The results show that the T1000G carbon fibers present the similar round shape with a smooth surface before and after graphitization, indicating the carbon fibers are fabricated by dry–wet spinning. In comparison, the commercial high-strength and high-modulus PAN-based carbon fibers (M40JB and M55JB) present elliptical shapes with ridges and grooves on the surface, indicating the carbon fibers are fabricated by wet spinning. After graphitization treatment from 2300 to 2600 °C under a constant stretching of 600 cN, the Young’s modulus of the T1000G carbon fibers increases from about 436 to 484 GPa, and their tensile strength decreases from about 5.26 to 4.45 GPa. The increase in Young’s modulus of the graphitized T1000G carbon fibers is attributed to the increase in the crystallite sizes and the preferred orientation of graphite crystallites along the fiber longitudinal direction under a constant stretching condition. In comparison with the M40JB and the M55JB carbon fibers, the graphitized T1000G carbon fibers are easier to be oxidized, which can be contributed to the formation of more micropores and defects during the graphitization process, thus leading to the decrease in the tensile strength.

The microstructures and mechanical properties of ultra-high-strength PAN-based carbon fibers during graphitization under a constant stretching

Ye Chong,Wu Huang,Huang Dong,Li Baoliu,Shen Ke,Yang Jianxiao,Liu Jinshui,Li Xuanke 한국탄소학회 2019 Carbon Letters Vol.29 No.5

Commercial ultra-high-strength PAN-based carbon fibers (T1000G) were heat-treated at the temperature range of 2300–2600 °C under a constant stretching of 600 cN. After continuous high-temperature graphitization treatment, microstructures, mechanical properties and thermal stability of the carbon fibers were investigated. The results show that the T1000G carbon fibers present the similar round shape with a smooth surface before and after graphitization, indicating the carbon fibers are fabricated by dry–wet spinning. In comparison, the commercial high-strength and high-modulus PAN-based carbon fibers (M40JB and M55JB) present elliptical shapes with ridges and grooves on the surface, indicating the carbon fibers are fabricated by wet spinning. After graphitization treatment from 2300 to 2600 °C under a constant stretching of 600 cN, the Young’s modulus of the T1000G carbon fibers increases from about 436 to 484 GPa, and their tensile strength decreases from about 5.26 to 4.45 GPa. The increase in Young’s modulus of the graphitized T1000G carbon fibers is attributed to the increase in the crystallite sizes and the preferred orientation of graphite crystallites along the fiber longitudinal direction under a constant stretching condition. In comparison with the M40JB and the M55JB carbon fibers, the graphitized T1000G carbon fibers are easier to be oxidized, which can be contributed to the formation of more micropores and defects during the graphitization process, thus leading to the decrease in the tensile strength.