Tetrahydrofuran(THF) extract of coal tar pitch(CTP) was used instead of blending CTP with pretreated pyrolysis fuel oil to prepare an isotropic pitch precursor with excellent spinnability for general-purpose carbon fi...Tetrahydrofuran(THF) extract of coal tar pitch(CTP) was used instead of blending CTP with pretreated pyrolysis fuel oil to prepare an isotropic pitch precursor with excellent spinnability for general-purpose carbon fibre through bromination-dehydrobromination. The feasibility and effectiveness of synthesising an isotropic pitch precursor derived from THF-soluble(CTP-THFs) is demonstrated in this study.The results show that CTP-THFs contains more light components than CTP;CTP-THFs and CTP monomer proportions were 62.52% and 45.32%, respectively. However, based on comparisons of CTP-THFsBr0 and CTPBr0 characterisations, CTP-THFs exhibits better polycondensation than CTP. Bromination-dehydrobro mination promotes polycondensation of pitch precursors, leading to greater carbon aromaticity in CTP-THFsBr5, CTP-THFsBr10, and CTP-THFsBr15 than that in CTP-THFsBr0 and CTPBr0. CTP-THFsBr5 and CTP-THFsBr10 have excellent spinnability even with softening points as high as 230 ℃. The pericondensed carbon and carbon aromaticity of CTP-THFsBr5 and CTP-THFsBr10 are high owing to the higher degree of polycondensation;however, they still possess a more linear molecular structure. The as-prepared carbon fibre exhibits homogeneity and uniformity, and the mechanical performance is comparable with that of commercial general-purpose carbon fibre products.展开更多
By a polarized light optical microscopy with a hot stage, liquid phase nuclear magnetic resonance 13 C NMR and 1 H NMR, X ray diffractometry and scanning electron microscopy (SEM), the factors that affect the formatio...By a polarized light optical microscopy with a hot stage, liquid phase nuclear magnetic resonance 13 C NMR and 1 H NMR, X ray diffractometry and scanning electron microscopy (SEM), the factors that affect the formation of mesophase in C/C composites, such as pressure, quinoline insolubles (QI) and heterocylic compounds, were analyzed. Further, the graphitizability of the resultant carbon was discussed. The results indicate that to some degree, QI contents accelerate the formation of mesophase at atmospheric pressure; while at high pressure, the coalescence and growth of mesophase spherules are impeded and the resultant coke produced from higher QI content pitch is harder to be graphitized. This is in agreement with the transfer of microstructure from domain anisotropy to fine grained mosaics.展开更多
To improve the electrochemical performance of graphite anode materials,pitches with various softening points(150℃,180℃,200℃,and 250℃)were prepared from ethylene tar and used to coat graphite through a liquid coati...To improve the electrochemical performance of graphite anode materials,pitches with various softening points(150℃,180℃,200℃,and 250℃)were prepared from ethylene tar and used to coat graphite through a liquid coating process.The effects of the softening point of the pitch and the coating amount on the microstructure and electrochemical properties of graphite were studied by methods including thermogravimetric analysis,X-ray diffraction,Raman spectroscopy,surface area analysis,scanning electron microscopy,transmission electron microscopy,and electrochemical testing.The graphite particles were coated uniformly by the pyrolytic carbon in the pitch.The coating changed the degree of graphitization,decreased the average specific surface area,and improved the electrochemical performance significantly.The best battery anode performance was obtained when the mass ratio of pitch to graphite was 10%,the heat treatment temperature was 1100℃,and the softening point of the pitch was 250℃.Under the optimum conditions,the irreversible capacity loss in the first cycle at 0.1 C was only 23 mAh/g,and the first Coulombic efficiency reached 94.2%.The capacity retention rate was 98.3%after 100 charge-discharge cycles at 0.1 C.展开更多
There are numerous methods and additives available to improve the durability and quality of road bitumen. A coal tar obtained by coal coking was distilled in a laboratory into fractions of initial boiling point IBP-18...There are numerous methods and additives available to improve the durability and quality of road bitumen. A coal tar obtained by coal coking was distilled in a laboratory into fractions of initial boiling point IBP-180℃ (gasoline-like fuel), 180℃ - 360℃ (diesel-like fuel), and >360℃ (residue or coal tar pitch). The coal tar pitch was added into road bitumen by up to 1 - 5 wt% and investigated the alteration of physical and chemical properties. The physico-mechanical properties of coal tar pitch and bitumen blends, as well as the chemical group composition, were determined using standard techniques (MNS) and the SARA method, respectively. Results of 3% coal tar pitch addition into bitumen enhanced ductility by 12.4% and softening point by 1.6℃. We found that blending with bitumen coal tar pitch as a modifier could improve bitumen properties.展开更多
A new approach is provided to resolve the large-scale applications of coal tar pitch. Carbon foams with uniform pore size are prepared at the foaming pressure of normal pressure using coal tar pitch as raw materials. ...A new approach is provided to resolve the large-scale applications of coal tar pitch. Carbon foams with uniform pore size are prepared at the foaming pressure of normal pressure using coal tar pitch as raw materials. The physical and chemical performance of high softening point pitch(HSPP) can be regulated by vacuumizing owing to the cooperation of vacuumizing and polycondensation. Results indicate that the optimum softening point and weight ratio of quinoline insoluble are about 292℃ and 65.7%, respectively. And the optimum viscosity of HSPP during the foaming process is distributed in the range of 1000-10000 Pa·s. The resultant carbon foam exhibits excellent performance, such as uniform pore structure, high compressive strength(4.7 MPa), low thermal conductivity(0.07 W·m^(-1) ·K^(-1)), specially, it cannot be fired under the high temperature of 1200 ℃.Thus, this kind of carbon foam is a potential candidate for thermal insulation material applied in energy saving building.展开更多
Parent coal tar pitch(CTP)was modified with boric acid(BA),cinnamaldehyde(CMA)and the mixture of BA and CMA,respectively.The parent CTP and three modified CTPs were characterized by elemental analysis,thermogravimetri...Parent coal tar pitch(CTP)was modified with boric acid(BA),cinnamaldehyde(CMA)and the mixture of BA and CMA,respectively.The parent CTP and three modified CTPs were characterized by elemental analysis,thermogravimetric analysis,Fourier transform infrared(FT-IR)spectroscopy and scanning electron microscopy.The four samples were carbonized at different temperatures and resultant carbonized products were characterized by FT-IR spectroscopy,X-ray diffraction and polarized-light microscopy.The results show that the morphologies and carbonization behaviors of the parent CTP and modified CTPs are quite different.The carbonization yield of the CTP modified with the mixture of BA and CMA is higher than that of CTP modified with BA or CMA only.In addition,the modification of CTP with 7 g of BA and 10 ml of CMA results in an increase in carbonization yield by5.64%.During the pyrolysis of modified CTPs,the dehydration of BA or the distillation of CMA occurs at the temperature lower than 300°C,and methyl and methylene groups of the modified CTPs disappear gradually as temperature rises.Furthermore,the modification of CTP by the mixture of BA and CMA results in more intensive mesophase spheres than other modified CTPs,and the modified CTP is easier to be carbonized to form graphitic carbon.展开更多
Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch.The characteristics of mesophase pitches were examined using polarized light optical microscopy,apparent viscometry,Fourier transf...Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch.The characteristics of mesophase pitches were examined using polarized light optical microscopy,apparent viscometry,Fourier transform infrared spectrometry,1H nuclear magnetic resonance spectrometry,and X-ray diffractometry.The properties of the mesophase pitch were greatly improved because of the eutectic effect.The soluble content increased from 5% to 56%,the mesophase itself increased from 32% to 100%,and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch.The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization.The increased number of alkyl groups,which are mainly methylene groups,altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.展开更多
In order to enlarge the use of coal tar pitch(CTP) in paving road,CTP and 60th paving pitch (PP) were extracted by n-heptane,toluene and ethanol step by step in a Soxhlet apparatus.The three fractions of CTP and PP we...In order to enlarge the use of coal tar pitch(CTP) in paving road,CTP and 60th paving pitch (PP) were extracted by n-heptane,toluene and ethanol step by step in a Soxhlet apparatus.The three fractions of CTP and PP were detected using UV-absorption(UV-A),elemental analyses(EA) and nuclear magnetic resonance(NMR) firstly as a whole unit after quality characterization of physical nature of CTP and PP were finished.The CTP had more saturate aliphatic and residue compounds dissolved in ethanol.On the other hand there were more continental type structures of aromatic ring than that of PP.There was almost no residue in PP after extracted by ethanol.The results explained why CTP was crisp in cold winter and was soften in summer.The following research will focus on how to change the chemical construction of CTP into the relative similar structures with those of PP through adding polymer.展开更多
The water soluble coal tar pitches(WS-CTPs)were successfully prepared and used to construct the MnO_(2)@C composite materials by a hydrothermal method.It is interestingly observed that the structures and morphologies ...The water soluble coal tar pitches(WS-CTPs)were successfully prepared and used to construct the MnO_(2)@C composite materials by a hydrothermal method.It is interestingly observed that the structures and morphologies of MnO_(2)@C materials can be controlled by controlling the dosages of WS-CTPs and KMnO4.Meanwhile,it is aware that MnO_(2)exists in the MnO_(2)@C materials in an amorphous state.Compared with MnO_(2),MnO_(2)@C materials output a remarkable improvement in electrochemical performance.For instance,MnO_(2)@C-0.3 shows the storage capacity at 965.7 mA h g^(−1)after 300 cycles at a current density of 0.1 A g^(−1).In addition,after 600 cycles at a current density of 1.0 A g^(−1),the storage capacity of MnO_(2)@C-0.3 still keeps 450.3 mA h g^(−1),indicating that MnO_(2)@C-0.3 owns tremendous cycle stability at a high current density.In view of the fact that the coal tar pitches possess great cost advantages,the strategy of using WS-CTPs as a carbon source to cover the metal oxides is a competitive way to expand the application of metal oxides in the fabrication of electrodes of LIBs.展开更多
基金the financial support provided by the National Natural Science Foundation of China (22008254)the Fundamental Research Funds for the Central Universities (2020XJHH01)+1 种基金the National Training Program of Innovation and Entrepreneurship for Undergraduates (C202003309)China University of Mining and Technology (Beijing) Yueqi Outstanding Scholar Project (2020JCB02)。
文摘Tetrahydrofuran(THF) extract of coal tar pitch(CTP) was used instead of blending CTP with pretreated pyrolysis fuel oil to prepare an isotropic pitch precursor with excellent spinnability for general-purpose carbon fibre through bromination-dehydrobromination. The feasibility and effectiveness of synthesising an isotropic pitch precursor derived from THF-soluble(CTP-THFs) is demonstrated in this study.The results show that CTP-THFs contains more light components than CTP;CTP-THFs and CTP monomer proportions were 62.52% and 45.32%, respectively. However, based on comparisons of CTP-THFsBr0 and CTPBr0 characterisations, CTP-THFs exhibits better polycondensation than CTP. Bromination-dehydrobro mination promotes polycondensation of pitch precursors, leading to greater carbon aromaticity in CTP-THFsBr5, CTP-THFsBr10, and CTP-THFsBr15 than that in CTP-THFsBr0 and CTPBr0. CTP-THFsBr5 and CTP-THFsBr10 have excellent spinnability even with softening points as high as 230 ℃. The pericondensed carbon and carbon aromaticity of CTP-THFsBr5 and CTP-THFsBr10 are high owing to the higher degree of polycondensation;however, they still possess a more linear molecular structure. The as-prepared carbon fibre exhibits homogeneity and uniformity, and the mechanical performance is comparable with that of commercial general-purpose carbon fibre products.
文摘By a polarized light optical microscopy with a hot stage, liquid phase nuclear magnetic resonance 13 C NMR and 1 H NMR, X ray diffractometry and scanning electron microscopy (SEM), the factors that affect the formation of mesophase in C/C composites, such as pressure, quinoline insolubles (QI) and heterocylic compounds, were analyzed. Further, the graphitizability of the resultant carbon was discussed. The results indicate that to some degree, QI contents accelerate the formation of mesophase at atmospheric pressure; while at high pressure, the coalescence and growth of mesophase spherules are impeded and the resultant coke produced from higher QI content pitch is harder to be graphitized. This is in agreement with the transfer of microstructure from domain anisotropy to fine grained mosaics.
基金This work was financially supported by the Research Program of China Petrochemical Corporation(SINOPEC 121023).
文摘To improve the electrochemical performance of graphite anode materials,pitches with various softening points(150℃,180℃,200℃,and 250℃)were prepared from ethylene tar and used to coat graphite through a liquid coating process.The effects of the softening point of the pitch and the coating amount on the microstructure and electrochemical properties of graphite were studied by methods including thermogravimetric analysis,X-ray diffraction,Raman spectroscopy,surface area analysis,scanning electron microscopy,transmission electron microscopy,and electrochemical testing.The graphite particles were coated uniformly by the pyrolytic carbon in the pitch.The coating changed the degree of graphitization,decreased the average specific surface area,and improved the electrochemical performance significantly.The best battery anode performance was obtained when the mass ratio of pitch to graphite was 10%,the heat treatment temperature was 1100℃,and the softening point of the pitch was 250℃.Under the optimum conditions,the irreversible capacity loss in the first cycle at 0.1 C was only 23 mAh/g,and the first Coulombic efficiency reached 94.2%.The capacity retention rate was 98.3%after 100 charge-discharge cycles at 0.1 C.
文摘There are numerous methods and additives available to improve the durability and quality of road bitumen. A coal tar obtained by coal coking was distilled in a laboratory into fractions of initial boiling point IBP-180℃ (gasoline-like fuel), 180℃ - 360℃ (diesel-like fuel), and >360℃ (residue or coal tar pitch). The coal tar pitch was added into road bitumen by up to 1 - 5 wt% and investigated the alteration of physical and chemical properties. The physico-mechanical properties of coal tar pitch and bitumen blends, as well as the chemical group composition, were determined using standard techniques (MNS) and the SARA method, respectively. Results of 3% coal tar pitch addition into bitumen enhanced ductility by 12.4% and softening point by 1.6℃. We found that blending with bitumen coal tar pitch as a modifier could improve bitumen properties.
基金Supported by the National Natural Science Foundation of China(51472086,51002051)CAS Key Laboratory of Carbon Materials(No KLCMKFJJ1703)
文摘A new approach is provided to resolve the large-scale applications of coal tar pitch. Carbon foams with uniform pore size are prepared at the foaming pressure of normal pressure using coal tar pitch as raw materials. The physical and chemical performance of high softening point pitch(HSPP) can be regulated by vacuumizing owing to the cooperation of vacuumizing and polycondensation. Results indicate that the optimum softening point and weight ratio of quinoline insoluble are about 292℃ and 65.7%, respectively. And the optimum viscosity of HSPP during the foaming process is distributed in the range of 1000-10000 Pa·s. The resultant carbon foam exhibits excellent performance, such as uniform pore structure, high compressive strength(4.7 MPa), low thermal conductivity(0.07 W·m^(-1) ·K^(-1)), specially, it cannot be fired under the high temperature of 1200 ℃.Thus, this kind of carbon foam is a potential candidate for thermal insulation material applied in energy saving building.
基金Supported by the Natural Science Foundation of Shaanxi Province（2009GM6001-1） the Foundation for Fundamental Research of Northwestern Polytechnical University（JC201030）
文摘Parent coal tar pitch(CTP)was modified with boric acid(BA),cinnamaldehyde(CMA)and the mixture of BA and CMA,respectively.The parent CTP and three modified CTPs were characterized by elemental analysis,thermogravimetric analysis,Fourier transform infrared(FT-IR)spectroscopy and scanning electron microscopy.The four samples were carbonized at different temperatures and resultant carbonized products were characterized by FT-IR spectroscopy,X-ray diffraction and polarized-light microscopy.The results show that the morphologies and carbonization behaviors of the parent CTP and modified CTPs are quite different.The carbonization yield of the CTP modified with the mixture of BA and CMA is higher than that of CTP modified with BA or CMA only.In addition,the modification of CTP with 7 g of BA and 10 ml of CMA results in an increase in carbonization yield by5.64%.During the pyrolysis of modified CTPs,the dehydration of BA or the distillation of CMA occurs at the temperature lower than 300°C,and methyl and methylene groups of the modified CTPs disappear gradually as temperature rises.Furthermore,the modification of CTP by the mixture of BA and CMA results in more intensive mesophase spheres than other modified CTPs,and the modified CTP is easier to be carbonized to form graphitic carbon.
基金the financial support by the Fundamental Research Funds for the Central Universities (No.2010QNA14)
文摘Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch.The characteristics of mesophase pitches were examined using polarized light optical microscopy,apparent viscometry,Fourier transform infrared spectrometry,1H nuclear magnetic resonance spectrometry,and X-ray diffractometry.The properties of the mesophase pitch were greatly improved because of the eutectic effect.The soluble content increased from 5% to 56%,the mesophase itself increased from 32% to 100%,and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch.The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization.The increased number of alkyl groups,which are mainly methylene groups,altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.
基金Supported by the Progress Plan of Science & Technology of Wuhan Pingmei Wugang Unite Coking Chemical Corp.Ltd,Ltd.of WISCO(2008Z012)
文摘In order to enlarge the use of coal tar pitch(CTP) in paving road,CTP and 60th paving pitch (PP) were extracted by n-heptane,toluene and ethanol step by step in a Soxhlet apparatus.The three fractions of CTP and PP were detected using UV-absorption(UV-A),elemental analyses(EA) and nuclear magnetic resonance(NMR) firstly as a whole unit after quality characterization of physical nature of CTP and PP were finished.The CTP had more saturate aliphatic and residue compounds dissolved in ethanol.On the other hand there were more continental type structures of aromatic ring than that of PP.There was almost no residue in PP after extracted by ethanol.The results explained why CTP was crisp in cold winter and was soften in summer.The following research will focus on how to change the chemical construction of CTP into the relative similar structures with those of PP through adding polymer.
基金This work was supported by the University of Science and Technology Liaoning(Grant Nos.601009816-39 and 2017RC03)the Liaoning Province Education Department of China(Grant Nos.601009887-16 and LJKQZ2021126)+1 种基金the National Natural Science Foundation of China(Grant Nos.51672117 and 51672118)the Postdoctoral Foundation Project of Shenzhen Polytechnic(Grant No.6020330007K).
文摘The water soluble coal tar pitches(WS-CTPs)were successfully prepared and used to construct the MnO_(2)@C composite materials by a hydrothermal method.It is interestingly observed that the structures and morphologies of MnO_(2)@C materials can be controlled by controlling the dosages of WS-CTPs and KMnO4.Meanwhile,it is aware that MnO_(2)exists in the MnO_(2)@C materials in an amorphous state.Compared with MnO_(2),MnO_(2)@C materials output a remarkable improvement in electrochemical performance.For instance,MnO_(2)@C-0.3 shows the storage capacity at 965.7 mA h g^(−1)after 300 cycles at a current density of 0.1 A g^(−1).In addition,after 600 cycles at a current density of 1.0 A g^(−1),the storage capacity of MnO_(2)@C-0.3 still keeps 450.3 mA h g^(−1),indicating that MnO_(2)@C-0.3 owns tremendous cycle stability at a high current density.In view of the fact that the coal tar pitches possess great cost advantages,the strategy of using WS-CTPs as a carbon source to cover the metal oxides is a competitive way to expand the application of metal oxides in the fabrication of electrodes of LIBs.
