- Email: [email protected]
C composite using a needled non-woven carbon fiber felt as a preform
Abstracts / Carbon 117 (2017) 488e490
of the composite were 826 m2$g-1, 0.42 cm3$g-1 and 0.64 nm, respectively. The catalytic activity of the ACFs for NO oxidation to NO2 was higher than that of a composite loaded with 10 wt% silicalite under dry conditions. However, the latter had a much better resistance to vapor and exhibited a more stable catalytic activity than the ACFs under moist conditions. [New Carbon Materials 2017, 32(1): 41-47] PREPARATION OF CARBON FIBERS FROM LOW-MOLECULAR-WEIGHT COMPOUNDS OBTAINED FROM LOW-RANK COAL AND BIOMASS BY SOLVENT EXTRACTION Xian Li 1, Xian-qing Zhu 1, Okuda Kenshiro 1, Zong Zhang 2, Ashida Ryuichi 1, Hong Yao 2, Miura Kouichi 3. 1 State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan, 430074, China; 2 Department of Chemical Engineering, Kyoto University, Kyotodaigaku Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan; 3 Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan Abstract: The practical use of carbon fibers is limited by their high price mainly due to the high price of precursors. We have examined a high temperature solvent extraction method to prepare carbon fiber precursors from low-rank coals and biomass, using a lignite from Australia and rice straw. 1-methylnaphthalene at 350 C was used for the extraction and some of the extract in the solvent was precipated at room temperature. The soluble fractions at room temperature were obtained for use as the precursors by solvent evaporation. They were spun into fibers by a centrifuge spinning system and were then were extracted by cyclohexane to increase the softening point, stabilized by a temperature-programmed thermal treatment in air from 80 C to 330 C and carbonized at 1 000 C for 1 h in N2 to obtain carbon fibers. The carbon and oxygen contents of the final carbon fibers were 92 and 6.0 wt%, respectively, similar to those of commercial carbon fibers. The fiber diameter was around 4-6 mm. The soluble fractions were found to be promising low-cost precursors for carbon fibers. [New Carbon Materials 2017, 32(1): 48-55] EFFECT OF GRAPHENE OXIDE ADDITION ON THE INTERLAMINAR SHEAR PROPERTY OF CARBON FIBER-REINFORCED EPOXY COMPOSITES Xiao Han, Yan Zhao, Jian-ming Sun, Ye Li, Jin-dong Zhang, Yue Hao. School of Materials Science and Engineering, Beihang University, Beijing, 100191, China Abstract: Carbon fiber-reinforced composites were manufactured by hot pressing stacked carbon fiber prepregs using graphene oxide (GO)modified epoxy resin as the matrix. Tetrahydrofuran was used as the solvent to disperse GO in the epoxy resin. Results showed that a homogeneous GO-modified epoxy system could be obtained, which was stable for approximately 3 h, long enough to produce the prepreg. The incorporation of 0.10 wt% GO into the epoxy resin achieved the largest interlaminar shear strength (ILSS) of 96.14 MPa for laminates, 8.05% higher than that without GO. Also, the glass transition temperature of the composite was increased by approximately 5 C. The improvement of ILSS could be attributed to the toughening of the epoxy resin and an improvement in the interfacial adhesion between carbon fibers and epoxy matrix. [New Carbon Materials 2017, 32(1): 56-62] FABRICATION AND PERFORMANCE OF A C/C COMPOSITE USING A NEEDLED NON-WOVEN CARBON FIBER FELT AS A PREFORM Yan Li 1, Hong Cui 1, 2, Rui Zheng 2, A-lin Ji 2, Shao-jian Zhou 2. 1 School of Materials Science, Northwestern Polytechnic University, Xi'an, 710072, China; 2 Xi'an Aerospace Composites Research Institute, Xi'an, 710025, China Abstract: A C/C composite was prepared by chemical vapor infiltration followed by repeated pitch impregnation and high pressure carbonization to a final density of 1.9 g/cm3 using a needled non-woven carbon fiber felt preform. Its mechanical properties were compared with a 3D woven C/C composite. Results indicated that the axial tensile
489
strength of the needled C/C composite was 24.5 and 52.88 MPa at room temperature and 2 800 C, respectively, correspondingly 138 and 170% higher than that of the 3D woven C/C composite. The failure mode of the needled composite was pseudoplastic. The axial thermal expansion coefficient of the needled composite at 1 000 C was only 1.40910-6/ C, 64% lower than that of the 3D woven composite. The needled C/C composite exhibits excellent mechanical strength and thermal physical properties which make it potentially useful for a solid rocket motor. [New Carbon Materials 2017, 32(1): 63-70] A GRAPHENE/PVDF/PP MULTILAYER COMPOSITE SEPARATOR FOR LONG-LIFE AND HIGH POWER LITHIUM-ION BATTERIES Ai-xiu Bu 1, 2, Yong Tan 2, Ruo-pian Fang 1, Feng Li 1, Song-feng Pei 1, Wencai Ren 1. 1 Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110010, China; 2 Shenyang Ligong University, Shenyang, 110159, China Abstract: The separator is an important part of lithium-ion batteries and its optimization from both material and structural considerations can improve the performance of the battery. We prepared multilayer separators by coating a slurry containing graphene and PVDF in N-methylpyrrolidone on one side of a commercial polypropylene (PP) separator, followed by water treatment at 60 C for 6 h and vacuum drying at 60 C for 12 h to manipulate the pore structure of the composite layer. Results indicate that the discharge capacities of batteries using PP and the composite separator were nearly the same at a low rate of 0.5C. However, the capacity of the former at a high rate of 5C fades quickly while that of the latter remains almost unchanged after 600 cycles. The composite separators have a high absorption and wettability of the electrolyte, resulting in an improved conductivity. [New Carbon Materials 2017, 32(1): 71-76] EFFECTS OF A DIOCTYL PHTHALATE ADDITION TO COAL TAR PITCH ON THE MICROSTRUCTURES AND ELECTROCHEMICAL PROPERTIES OF DERIVED SEMI-COKES Liang-cheng Guo, Li-e Jin, Cun-gui Zhong, Ying Wang, Qing Cao. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China Abstract: Coal tar pitch (CTP) and dioctyl phthalate (DOP) were cocarbonized and the effects of the DOP addition on the thermal behavior of CTP, and the microstructures and electrochemical properties of semi-cokes derived from it were investigated by TGA, polarized light microscopy, SEM, XRD and electrochemical impedance spectroscopy (EIS). Results indicate that the weight loss rates of mixtures of CTP and DOP are slower than that of CTP, indicating that polycondensation between CTP and DOP takes place during co-carbonization. The Lc values of the CTP-DOP cokes are larger while their d002 values are smaller than those of the CTP coke. The electrical conductivities of the CTP-DOP cokes are better than that of the CTP coke as revealed by EIS. [New Carbon Materials 2017, 32(1): 77-85] MODELLING AND OPTIMIZATION OF THE PORE STRUCTURE OF CARBON AEROGELS USING AN ARTIFICIAL NEURAL NETWORK Zhen Yang, Wen-ming Qiao, Xiao-yi Liang. State Key Laboratory of Chemical Engineering, Key Laboratory for Special functional Polymer Materials and Their Related Technologies, Ministry of Education, East China University of Science and Technology, Shanghai, 200237, China Abstract: An intelligent simulation method for predicting and optimizing the pore structure of carbon aerogels is proposed by using an artificial neural network (ANN) algorithm. The ANN model has been optimized based on an improved genetic algorithm from six typical training algorithms. The volumes and diameters of pores in the simulated samples are predicted by the optimized ANN model, which shows correlation coefficients R2 of 0.992 and 0.981 and root-mean-square prediction errors (RMSPE) of 0.077 and 0.054 between the predicted and experimental
of the composite were 826 m2$g-1, 0.42 cm3$g-1 and 0.64 nm, respectively. The catalytic activity of the ACFs for NO oxidation to NO2 was higher than that of a composite loaded with 10 wt% silicalite under dry conditions. However, the latter had a much better resistance to vapor and exhibited a more stable catalytic activity than the ACFs under moist conditions. [New Carbon Materials 2017, 32(1): 41-47] PREPARATION OF CARBON FIBERS FROM LOW-MOLECULAR-WEIGHT COMPOUNDS OBTAINED FROM LOW-RANK COAL AND BIOMASS BY SOLVENT EXTRACTION Xian Li 1, Xian-qing Zhu 1, Okuda Kenshiro 1, Zong Zhang 2, Ashida Ryuichi 1, Hong Yao 2, Miura Kouichi 3. 1 State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan, 430074, China; 2 Department of Chemical Engineering, Kyoto University, Kyotodaigaku Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan; 3 Institute of Advanced Energy, Kyoto University, Gokasho, Uji, Kyoto, 611-0011, Japan Abstract: The practical use of carbon fibers is limited by their high price mainly due to the high price of precursors. We have examined a high temperature solvent extraction method to prepare carbon fiber precursors from low-rank coals and biomass, using a lignite from Australia and rice straw. 1-methylnaphthalene at 350 C was used for the extraction and some of the extract in the solvent was precipated at room temperature. The soluble fractions at room temperature were obtained for use as the precursors by solvent evaporation. They were spun into fibers by a centrifuge spinning system and were then were extracted by cyclohexane to increase the softening point, stabilized by a temperature-programmed thermal treatment in air from 80 C to 330 C and carbonized at 1 000 C for 1 h in N2 to obtain carbon fibers. The carbon and oxygen contents of the final carbon fibers were 92 and 6.0 wt%, respectively, similar to those of commercial carbon fibers. The fiber diameter was around 4-6 mm. The soluble fractions were found to be promising low-cost precursors for carbon fibers. [New Carbon Materials 2017, 32(1): 48-55] EFFECT OF GRAPHENE OXIDE ADDITION ON THE INTERLAMINAR SHEAR PROPERTY OF CARBON FIBER-REINFORCED EPOXY COMPOSITES Xiao Han, Yan Zhao, Jian-ming Sun, Ye Li, Jin-dong Zhang, Yue Hao. School of Materials Science and Engineering, Beihang University, Beijing, 100191, China Abstract: Carbon fiber-reinforced composites were manufactured by hot pressing stacked carbon fiber prepregs using graphene oxide (GO)modified epoxy resin as the matrix. Tetrahydrofuran was used as the solvent to disperse GO in the epoxy resin. Results showed that a homogeneous GO-modified epoxy system could be obtained, which was stable for approximately 3 h, long enough to produce the prepreg. The incorporation of 0.10 wt% GO into the epoxy resin achieved the largest interlaminar shear strength (ILSS) of 96.14 MPa for laminates, 8.05% higher than that without GO. Also, the glass transition temperature of the composite was increased by approximately 5 C. The improvement of ILSS could be attributed to the toughening of the epoxy resin and an improvement in the interfacial adhesion between carbon fibers and epoxy matrix. [New Carbon Materials 2017, 32(1): 56-62] FABRICATION AND PERFORMANCE OF A C/C COMPOSITE USING A NEEDLED NON-WOVEN CARBON FIBER FELT AS A PREFORM Yan Li 1, Hong Cui 1, 2, Rui Zheng 2, A-lin Ji 2, Shao-jian Zhou 2. 1 School of Materials Science, Northwestern Polytechnic University, Xi'an, 710072, China; 2 Xi'an Aerospace Composites Research Institute, Xi'an, 710025, China Abstract: A C/C composite was prepared by chemical vapor infiltration followed by repeated pitch impregnation and high pressure carbonization to a final density of 1.9 g/cm3 using a needled non-woven carbon fiber felt preform. Its mechanical properties were compared with a 3D woven C/C composite. Results indicated that the axial tensile
489
strength of the needled C/C composite was 24.5 and 52.88 MPa at room temperature and 2 800 C, respectively, correspondingly 138 and 170% higher than that of the 3D woven C/C composite. The failure mode of the needled composite was pseudoplastic. The axial thermal expansion coefficient of the needled composite at 1 000 C was only 1.40910-6/ C, 64% lower than that of the 3D woven composite. The needled C/C composite exhibits excellent mechanical strength and thermal physical properties which make it potentially useful for a solid rocket motor. [New Carbon Materials 2017, 32(1): 63-70] A GRAPHENE/PVDF/PP MULTILAYER COMPOSITE SEPARATOR FOR LONG-LIFE AND HIGH POWER LITHIUM-ION BATTERIES Ai-xiu Bu 1, 2, Yong Tan 2, Ruo-pian Fang 1, Feng Li 1, Song-feng Pei 1, Wencai Ren 1. 1 Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, 110010, China; 2 Shenyang Ligong University, Shenyang, 110159, China Abstract: The separator is an important part of lithium-ion batteries and its optimization from both material and structural considerations can improve the performance of the battery. We prepared multilayer separators by coating a slurry containing graphene and PVDF in N-methylpyrrolidone on one side of a commercial polypropylene (PP) separator, followed by water treatment at 60 C for 6 h and vacuum drying at 60 C for 12 h to manipulate the pore structure of the composite layer. Results indicate that the discharge capacities of batteries using PP and the composite separator were nearly the same at a low rate of 0.5C. However, the capacity of the former at a high rate of 5C fades quickly while that of the latter remains almost unchanged after 600 cycles. The composite separators have a high absorption and wettability of the electrolyte, resulting in an improved conductivity. [New Carbon Materials 2017, 32(1): 71-76] EFFECTS OF A DIOCTYL PHTHALATE ADDITION TO COAL TAR PITCH ON THE MICROSTRUCTURES AND ELECTROCHEMICAL PROPERTIES OF DERIVED SEMI-COKES Liang-cheng Guo, Li-e Jin, Cun-gui Zhong, Ying Wang, Qing Cao. College of Chemistry and Chemical Engineering, Taiyuan University of Technology, Taiyuan, 030024, China Abstract: Coal tar pitch (CTP) and dioctyl phthalate (DOP) were cocarbonized and the effects of the DOP addition on the thermal behavior of CTP, and the microstructures and electrochemical properties of semi-cokes derived from it were investigated by TGA, polarized light microscopy, SEM, XRD and electrochemical impedance spectroscopy (EIS). Results indicate that the weight loss rates of mixtures of CTP and DOP are slower than that of CTP, indicating that polycondensation between CTP and DOP takes place during co-carbonization. The Lc values of the CTP-DOP cokes are larger while their d002 values are smaller than those of the CTP coke. The electrical conductivities of the CTP-DOP cokes are better than that of the CTP coke as revealed by EIS. [New Carbon Materials 2017, 32(1): 77-85] MODELLING AND OPTIMIZATION OF THE PORE STRUCTURE OF CARBON AEROGELS USING AN ARTIFICIAL NEURAL NETWORK Zhen Yang, Wen-ming Qiao, Xiao-yi Liang. State Key Laboratory of Chemical Engineering, Key Laboratory for Special functional Polymer Materials and Their Related Technologies, Ministry of Education, East China University of Science and Technology, Shanghai, 200237, China Abstract: An intelligent simulation method for predicting and optimizing the pore structure of carbon aerogels is proposed by using an artificial neural network (ANN) algorithm. The ANN model has been optimized based on an improved genetic algorithm from six typical training algorithms. The volumes and diameters of pores in the simulated samples are predicted by the optimized ANN model, which shows correlation coefficients R2 of 0.992 and 0.981 and root-mean-square prediction errors (RMSPE) of 0.077 and 0.054 between the predicted and experimental