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Liu, Jinchang,Shimanoe, Hiroki,Nakabayashi, Koji,Miyawaki, Jin,Ko, Seunghyun,Jeon, Young-Pyo,Yoon, Seong-Ho Elsevier 2018 Journal of industrial and engineering chemistry Vol.67 No.-
<P><B>Abstract</B></P> <P>For the first time, polyvinyl chloride (PVC) was used as an easily-handled chlorine source for preparation of isotropic pitch-based carbon fiber (IPCF) incorporating ethylene bottom oil (EO) as a raw material. Pitch precursors were prepared by the chlorination–dehydrochlorination triggered by chlorine radicals originated from PVC; aromatization and poly-condensation reactions occurred by polyene-type radicals from PVC. Radical production and co-carbonization were facilitated by pretreatments of EO through vacuum distillation, bromination, and additional heat treatment. Pitches were prepared by the co-carbonization of pretreated EO and EO containing 20wt% PVC, and had higher yields and better spinnability than those by simple distillation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> PVC was used as a chlorine source for the preparation of isotropic pitch precursors from EO. </LI> <LI> Isotropic pitches with excellent spinnability were fabricated by co-carbonization of EO with chlorine radicals from PVC. </LI> <LI> Pitch precursors prepared by chlorination–dehydrochlorination reactions showed higher yields and better spinnability. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Liu, Jinchang,Shimanoe, Hiroki,Nakabayashi, Koji,Miyawaki, Jin,Choi, Jong-Eun,Jeon, Young-Pyo,Yoon, Seong-Ho Elsevier 2018 Journal of industrial and engineering chemistry Vol.67 No.-
<P><B>Abstract</B></P> <P>An isotropic pitch precursor for fabricating carbon fibres was prepared by co-carbonization of ethylene bottom oil (EBO) and polyvinyl chloride (PVC). Various pre-treatments of EBO and PVC, and a high heating rate of 3°C/min with no holding time, were evaluated for their effects on the oxidative stabilization process and the mechanical stability of the resulting fibres. Our stabilization process enhanced the volatilization, oxidative reaction and decomposition properties of the precursor pitch, while the addition of PVC both decreased the onset time and accelerated the oxidative reaction. Aliphatic carbon groups played a critical role in stabilization. Microstructural characterization indicated that these were first oxidised to carbon–oxygen single bonds and then converted to carbon–oxygen double bonds. Due to the higher heating rate and lack of a holding step during processing, the resulting thermoplastic fibers did not completely convert to thermoset materials, allowing partially melted, adjacent fibres to fuse. Fiber surfaces were smooth and homogeneous. Of the various methods evaluated herein, carbon fibers derived from pressure-treated EBO and PVC exhibited the highest tensile strength. This work shows that enhancing the naphthenic component of a pitch precursor through the co-carbonization of pre-treated EBO with PVC improves the oxidative properties of the resulting carbon fibers.</P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>
Jinchang Liu,Hiroki Shimanoe,Koji Nakabayashi,Jin Miyawaki,고승현,전영표,윤성호 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.67 No.-
For the first time, polyvinyl chloride (PVC) was used as an easily-handled chlorine source for preparation of isotropic pitch-based carbon fiber (IPCF) incorporating ethylene bottom oil (EO) as a raw material. Pitch precursors were prepared by the chlorination–dehydrochlorination triggered by chlorine radicals originated from PVC; aromatization and poly-condensation reactions occurred by polyene-type radicals from PVC. Radical production and co-carbonization were facilitated by pretreatments of EO through vacuum distillation, bromination, and additional heat treatment. Pitches were prepared by the co-carbonization of pretreated EO and EO containing 20 wt% PVC, and had higher yields and better spinnability than those by simple distillation.
Jinchang Liu,Hiroki Shimanoe,Koji Nakabayashi,Jin Miyawaki,최종은,전영표,윤성호 한국공업화학회 2018 Journal of Industrial and Engineering Chemistry Vol.67 No.-
An isotropic pitch precursor for fabricating carbon fibres was prepared by co-carbonization of ethylene bottom oil (EBO) and polyvinyl chloride (PVC). Various pre-treatments of EBO and PVC, and a high heating rate of 3 °C/min with no holding time, were evaluated for their effects on the oxidative stabilization process and the mechanical stability of the resulting fibres. Our stabilization process enhanced the volatilization, oxidative reaction and decomposition properties of the precursor pitch, while the addition of PVC both decreased the onset time and accelerated the oxidative reaction. Aliphatic carbon groups played a critical role in stabilization. Microstructural characterization indicated that these were first oxidised to carbon–oxygen single bonds and then converted to carbon–oxygen double bonds. Due to the higher heating rate and lack of a holding step during processing, the resulting thermoplastic fibers did not completely convert to thermoset materials, allowing partially melted, adjacent fibres to fuse. Fiber surfaces were smooth and homogeneous. Of the various methods evaluated herein, carbon fibers derived from pressure-treated EBO and PVC exhibited the highest tensile strength. This work shows that enhancing the naphthenic component of a pitch precursor through the co-carbonization of pre-treated EBO with PVC improves the oxidative properties of the resulting carbon fibers.
Jinchang Liu,Hiroki Shimanoe,Jong‑Eun Choi,Seunghyun Ko,Young‑Pyo Jeon,Koji Nakabayashi,Jin Miyawaki,Seong‑Ho Yoon 한국탄소학회 2019 Carbon Letters Vol.29 No.2
Pitch precursors affording excellent spinnability, high-level oxidation-resistance, and good carbonization yields were prepared by bromination–dehydrobromination of various ratios of pyrolyzed fuel oil and coal tar pitch. The pitches exhibited spinnabilities that were much better than those of pitches prepared via simple distillation. A pitch prepared using a 1:2 ratio of fuel oil and coal tar pitch exhibited the best tensile strength. Pitch fibers of diameter 8.9 ± 0.1 μm were stabilized at 270 °C without soaking time after heating at a rate of 0.5 °C/min and carbonized at 1100 °C for 1 h after heating at 5 °C/min. The resulting carbon fibers exhibited a tensile strength, elongation, Young’s modulus, and average diameter of 1700 ± 170 MPa, 1.6 ± 0.1%, 106 ± 37 GPa, and 7.1 ± 0.2 μm, respectively.
Chen Junhui,Liu Yangqing,Ma Guangqiang,Yang Feiying,Zhan Zhigao,Guan Limei,Kuang Wendong,Wang Jinchang,Li Jianghuai,Han Fei,Jin Liang 한국응용곤충학회 2023 Journal of Asia-Pacific Entomology Vol.26 No.1
Mosquitoes bite human beings and transmit many diseases, such as malaria, dengue fever, and Zika virus. Vector control of mosquitoes is an effective strategy for reducing the spread of disease. However, extensive use of in secticides (e.g. pyrethroids and organophosphorus) has caused resistance in mosquitoes, which weakens the effectiveness of mosquito control. Phytochemicals have been considered an alternative approach to mosquito control. Essential oil (EO) was obtained from the leaves and flowers of Origanum vulgare, and its synergistic activity with piperonyl butoxide (PBO) was tested against Aedes albopictus and Culex pipiens quinquefasciatus larvae. Thirty-seven compounds were identified, among which carvacrol and thymol were two major constitu ents (30.73 % and 18.81 %, respectively). O. vulgare EO had a significant toxic effect against fourth-stage larvae of Cx. p. quinquefasciatus and Ae. albopictus, with LC 50 values of 17.51 and 75.90 mg/L. Carvacrol and thymol also each appeared to be more effective against Cx. p. quinquefasciatus (LC 50 = 19.30 and 11.56 mg/L, respectively) than Ae. albopictus (LC 50 = 26.62 and 26.66 mg/L, respectively). PBO interacted synergistically with O. vulgare EO, carvacrol and thymol with 2.60–6.26 times as much of the active compound needed without PBO as against Cx. p. quinquefasciatus and Ae. albopictus larvae. Overall, our results contribute to the development of new natural mosquito insecticides.