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2016, 31(1): .

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Research progress on the interconnection of carbon nanotubes

YANG Li-jun, CUI Jian-lei, WANG Yang, MEI Xue-song, WANG Wen-jun, XIE Hui

2016, 31(1): 1-17.

Abstract(695)

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The use of carbon nanotubes(CNTs) as conducting wires instead of copper wires for integrated circuits and very large scale integration has become more and more important as their sizes are being scaled down and quantum effects become evident owing to their one-dimensional structure, excellent electrical, thermal and mechanical properties.Interconnect technologies for CNTs have become an important research activity in recent years and the latest research progress is summarized.Methods include localized nanoscale chemical vapor deposition, electron, ion and laser beam irradiations, atom force microscopy using field-induced evaporation and anodic oxidation, and dip-pen nanolithography in the AFM using dynamic exchange between tapping and lifting.

Preparation of dopamine-functionalized multi-wall carbon nanotube/poly(amide-imide) composites and their thermal and mechanical properties

Shadpour Mallakpour, Amin Zadehnazari

2016, 31(1): 18-30. doi: 10.1016/S1872-5805(16)60001-X

Abstract(659)

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Covalent functionalization of MWCNT-COOH with dopamine was conducted by microwave irradiation and the dopamine-functionalized MWCNTs(MWCNT-Dop) were used as fillers in poly(amide-imide)(PAI) to improve its thermal and mechanical properties.Results indicate that the MWCNT-Dop is dispersed in PAI very well, which is ascribed to a good interfacial interaction between the MWCNT-Dop and PAI by hydrogen bonding.The temperatures at which 10 wt% weight loss occurs, and the limiting oxygen indices increase from 398 to 483℃ and 35.5% to 41.5%, respectively, as the MWCNT-Dop content increases from 0 to 15 wt%.The tensile strength and Young's modulus also increase from 79.4 to 120.3 MPa and 2.0 to 3.3 GPa, respectively, as the MWCNT-Dop content increases from 0 to 15 wt%.

Growth of carbon nanotubes on graphene by chemical vapor deposition

ZHAO Jian-guo, XING Bao-yan, YANG Hui, PAN Qi-liang, LI Zuo-peng, LIU Zhan-jun

2016, 31(1): 31-36. doi: 10.1016/S1872-5805(16)60002-1

Abstract(529)

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Graphite oxide powder impregnated with an Ni(NO₃)₂ solution was freeze-dried, thermally-reduced at 300℃ and then chemical-vapor deposition at 1000℃ was used to grow carbon nanotubes(CNTs) on graphene using methane as the carbon source.The morphology and electrical conductivities of the graphite oxide, reduced graphene and CNT-graphene hybrids were characterized.Results indicate that the density of CNTs on the graphene and the electrical conductivity of the hybrids increase with increasing Ni(NO₃)₂ concentration in the solution.Isolated graphene lamellae were connected by CNTs, giving rise to a 3D conducting network that provided conducting channels for electron transport.

A high energy density asymmetric supercapacitor based on a CoNi-layered double hydroxide and activated carbon

XIE Li-jing, SUN Guo-hua, XIE Long-fei, SU Fang-yuan, LI Xiao-ming, LIU Zhuo, KONG Qing-qiang, LU Chun-xiang, LI Kai-xi, CHEN Cheng-meng

2016, 31(1): 37-45. doi: 10.1016/S1872-5805(16)60003-3

Abstract(776)

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A high performance asymmetric supercapacitor was fabricated using a CoNi-layered double hydroxide(CoNi-LDH) as the positive electrode and activated carbon as the negative electrode in an electrolyte of 6 M aqueous KOH.The supercapacitor can be cycled reversibly in a wide potential window of 0-1.5 V and exhibits a remarkable energy density of 46.3 Wh·kg^-1 at a power density of 102.3 W·kg^-1, a high energy density of 25.6 Wh·kg^-1 even at a high power density of 1704.5 W·kg^-1 These values are much higher than those of a symmetric supercapacitor using only activated carbon(6.9 Wh·kg^-1).The results can be ascribed to the high specific capacitance and rate capability of the CoNi-LDH, and the complementary potential windows of the two electrodes that increase the working voltage of the supercapacitor.The supercapacitor also exhibits stable cycling with a 84.5% capacitance retention after 1000 cycles.

Recycling of carbon fibers in epoxy resin composites using supercritical 1-propanol

YAN Hua, LU Chun-xiang, JING De-qi, CHANG Chun-bao, LIU Na-xin, HOU Xiang-lin

2016, 31(1): 46-54. doi: 10.1016/S1872-5805(16)60004-5

Abstract(982)

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The effects of degradation temperature, reaction time and additive on the efficiency of the recovery of carbon fibers from their epoxy resin composites by supercritical 1-propanol were investigated.The recycled carbon fibers were characterized using SEM, TGA, XPS, contact angle measurements and single fiber tensile strength tests.Results indicated that the rate of decomposition of the resin increased, but the mechanical properties of the recycled fibers decreased slightly with temperature.The decomposition rate of the resin and tensile strength of the recycled carbon fibers decreased with reaction time.1 wt% of KOH additive in 1-propanol improved the recovery efficiency significantly.When the KOH concentration was increased beyond 1 wt% there was no obvious increase in the decomposition rate and the mechanical properties of the recycled fibers became worse.There were slight changes in the surface chemistry of the recycled carbon fibers and their contact angle with epoxy resin.Supercritical 1-propanol is an excellent recycling technology for carbon fibers in epoxy resin composites.

Effect of carbon nanofiber modification on the tribological properties of C/C composites

LU Xue-feng, XIAO Peng

2016, 31(1): 55-61.

Abstract(498)

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Carbon nanofibers(CNFs) were grown on a carbon fiber preform that was then densified by chemical vapor infiltration to prepare CNF-modified C/C composites.Micro-friction tests were used to investigate the effect of the CNF modification on the tribological properties of the composites at reciprocating abrasion rates from 600 to 1400 cycles/min over a distance of 15 mm and under a load of 60 N.Results show that the friction coefficient and the depth of the surface disturbed by the friction on the modified composites are not as sensitive to the rate as are the un-modified ones.When the rate is less than 1000 times/min, the modified composites have lower friction coefficients than the un-modified ones.The modified composites show steadier braking and their wear rates are much lower than the un-modified ones under the same rate.The wear debris formed from the matrix composed of CNFs and high-textured pyrocarbon helps maintain a high coefficient of friction and stable braking by forming a uniform film at the friction surface, resulting in the improved tribological properties.

The catalytic role of aluminium trichloride in the polymerization and carbonization of coal tar

DUAN Miao, TIAN Yong-ming, LI Si-zhong

2016, 31(1): 62-67. doi: 10.1016/S1872-5805(16)60005-7

Abstract(602)

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The polymerization and carbonization of coal tar was carried out at different temperatures from 633 to 1873 K using aluminium trichloride as catalyst.The polymerization degree, microstructures and optical texture of samples were analyzed by thermogravimetry, X-ray diffraction, Raman spectroscopy and polarized light microscopy.Results indicated that aluminium trichloride accelerated dehydrogenation during the polymerization of coal tar, and increased the toluene-insoluble fraction and carbonization yield.The presence of aluminium trichloride in the polymerized coal tar affected the microstructure of the coke by the formation of a quasi-isotropic structure.

Ply optimization of carbon fiber-reinforced plastics laminates based on a gradient-based optimization method with manufacturing constraints

LIU Zhe, JIN Da-feng, FAN Zhi-rui

2016, 31(1): 68-76.

Abstract(455)

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Abstract:
We optimized the number of plies and the stacking sequence of carbon fiber-reinforced plastics laminates using a gradient-based optimization method.To attain industrial relevance and reduce the risk of failure and the cost, certain manufacturing constraints were considered in the optimization.Manufacturing constraints were:1) candidate fiber orientations were limited to a finite set, 2) the bottom layer must be solid;3) an intermediate void was not allowed, and 4) two or three identical contiguous layers were allowed at most.In the optimization, the mass was minimized with stiffness and manufacturing constraints.In order to avoid introducing linear constraints to the optimization model, a material property interpolation scheme called a bi-value coding parameterization scheme was modified and the manufacturing constraints concerning fiber orientation were expressed as nonlinear constraints.Meanwhile, a dispersion constraint and penalty index were introduced to eliminate intermediate variables.The optimization problem was solved by a convex programming dual algorithm.Numerical examples validate the optimization method.

Modeling of carbon deposition from propane in chemical vapor infiltration

TANG Zhe-peng, XU Wei, LI Ai-jun, ZHANG Zhong-wei, BAI Rui-cheng, WANG Jun-shan, REN MU-su

2016, 31(1): 77-86.

Abstract(570)

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A reaction model including global reactions and 1074 elementary reactions of 285 species in both the gas phase and the solid surface was used to numerically simulate the gas phase composition and the deposition kinetics of pyrocarbon on carbon fibers in chemical vapor infiltration using propane.The global reactions were simplified to be the direct dehydrogenation reactions from the hydrocarbon species in the gas phase while the elementary reactions included 66 surface species and 250 elementary steps.Simulated results were compared with experiments performed in a perfectly stirred reactor at 2.6 kPa from 1173 to 1323 K for 0.5 to 4 s, using propane as the carbon precursor and nitrogen as the diluting gas.Excellent agreement between the simulated and the experimental results are found for both the gas phase compositions and deposition kinetics at various conditions.The simulation indicates that the pyrocarbon precursors are mostly small unsaturated species(acetylene and ethylene) and methyl radicals, and the deposition kinetics could be quantitatively described by the deposition of these species.

Synthesis of hollow carbon nanostructures using a ZnO template method

LIU Hong-yang, FENG Zhen-bao, WANG Jia, DIAO Jiang-yong, SU Dang-sheng

2016, 31(1): 87-91. doi: 10.1016/S1872-5805(16)60006-9

Abstract(517)

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A ZnO template approach for the large scale synthesis of hollow carbon nanostructures was developed.A diluted ethylbenzene stream was used to form a carbon layer on the template at a high temperature and a dilute HCl solution was used to etch the template.Hollow carbon nanotubes and hollow carbon nanospheres were fabricated using ZnO nanorods and nanospheres as the respective templates.The present process is simple, efficient and low cost, and may be extended to fabricate other hollow carbon nanostructures used in catalytic reactions and energy storage.

Dispersibility of graphite in water with different dispersants

WANG Li-li, YU Jin, LI Zheng-yuan

2016, 31(1): 92-96.

Abstract(1265)

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Octaphenyl polyoxyethyiene(OP-10), polyoxyethylene sorbitan monolaurate(Tween 20), sodium alcohol ether sulphate(AES), carboxymethylcellulose sodium(CMC), polyethylene glycol(PEG) 6000 and their mixtures were used to disperse graphite in water and their dispersion performance was investigated by spectrophotometry and Zeta potential measurements.Results indicate that three dispersant mixtures, (a) SGDF1 containing 100 g/L AES, 30 g/L Tween 20 and 20 g/L OP-10, (b) SGDF2 containing 100 g/L AES, 10 g/L Tween 20 and 20 g/L PEG-6000, and(c) SGDF3 containing 100 g/L AES, 10 g/L Tween 20 and 20 g/L CMC, have a good dispersibility for graphite in water.When the pH value is higher than 7, the dispersant mixtures have improved dispersibility.When the pH value is over 9, the Zeta potential of the graphite suspensions are high and their stability is the best.SGDF3 has the best dispersibility among all dispersants investigated.

2016 Vol. 31, No. 1

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