新型炭材料

WU Fa-yu, DU Jin-hong, LIU Chen-guang, LI Li-xiang, CHENG Hui-ming

2004, 19(02): 81-86.

Abstract(2986)

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Abstract:
The microstructure of micro-coiled carbon fibers synthesized by the catalytic decomposition of acetylene was analyzed using scanning electron microscopy, Raman spectroscopy, X-ray diffraction, thermogravimetry and nitrogen cryo-adsorption and compared with those of straight carbon fibers with a similar diameter. The crystalline sizes of the graphitic domains of the straight carbon fibers are larger than those of the micro-coiled fibers, but the outer layers of the micro-coiled carbon fibers are more ordered than that of the straight carbon fibers. The pore size distribution of straight carbon fibers is broad, while the pore size of the micro-coiled carbon fibers is narrowly distributed between 3nm and 4nm. The pore volume of micro-coiled carbon fibers is much higher than that of straight carbon fibers, and its BET surface area is almost ten times as much as that of straight carbon fibers. Results show that the oxidation resistance, hydrogen storage and electrochemical capacitance of the micro-coiled carbon fibers are superior to those of straight carbon fibers.

脉冲电弧放电电离甲醇/氨水溶液合成结晶氮化碳薄膜

MA Zhi-bin, WAN Jun, HUANG Yang-feng, WANG Jian-hua

2004, 19(02): 87-91.

Abstract(2841)

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The preparation of crystalline C3N4 films was investigated using a high density pulsed arc discharge plasma at atmospheric pressure and with a low substrate temperature. The direct current pulsed arc discharge plasma was excited using drops of methanol and ammonia water passing between high voltage electrodes. The morphologies and the structure of the specimens were analyzed using scanning electron microscopy, X-ray diffraction (XRD) and Raman spectroscopy. XRD patterns of the films prepared at a substrate temperature of 450℃ suggest that the film is composed of both α-C3N4 and β-C3N4 crystals, and Raman spectra show distinct peaks consistent with this. When the substrate temperature was increased to 550℃ Raman analysis showed that the deposits were carbon films.

热处理条件对氧化石墨结构和导电性能的影响（英）

XIAO Min, DU Xu-sheng, MENG Yue-zhong, GONG Ke-cheng

2004, 19(02): 92-96.

Abstract(2892)

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Abstract:
Graphite oxide (GO) is an oxidation product of graphite. Due to the embedding of the functional groups in the carbon layers, GO exhibits rich intercalation chemistry but also loses the good electrical conductivity of graphite. To investigate the possibility of reducing GO by thermal treatment, the variation of the structures of the GO with the heat treatment conditions were studied by XRD, SEM, IR spectroscopy and elemental analysis. It is found that heating rate plays an important role in the structure of the thermal treated GO. When subjected to rapid heating, GO was decomposed into a very light soot containing many pores of different sizes in the range of 50?nm to 5μm. When subjected to slow heating, GO tended to return to the graphene structure. The higher the thermal treatment temperature, the closer the crystal structure of the pyrolyzed GO is to that of the graphite and the higher the electrical conductivity of the pyrolyzed GO. The fact that the electrical conductivity of GO can be higher than 1?S/cm when it is treated at a temperature higher than 180℃ suggesting that it is possible to use GO as a precursor to make conducting polymer/carbon nanocomposites.

采用Z-Pin增强体的3D炭/炭复合材料层间断裂行为（英）

HAN Li-jun, LI Tie-hu, LIU Jian-jun, QIU Hai-peng, DING Hai-ying

2004, 19(02): 97-102.

Abstract(2951)

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Abstract:
Abstract: A novel form of preform consisting of plain weave fabric and z-pin through-thickness reinforcements was prepared. The carbon matrix was derived from a combination of isothermal chemical vapor infiltration and high pressure impregnation-carbonization of coal tar pitch. The interlaminar shear strength of the composites was characterized by a short beam interlaminar shear test and a double edge-notched tensile shear test. Hyper pseudoplastic fracture behavior of short beam interlaminar shear of 3D C/C composites was found, which is ascribed to the propagation of microcracks formed between laminations within and between bundles. Z-pins can have effective control over the progress of pseudoplastic fracture. True shear failure, which is characterized by the double edge-notched tensile test, shows non-pseudoplastic fracture progress that is ascribed to shear sliding occurring only within one interlamination. Both short beam interlaminar strength and double edge-notched tensile strength is 40～50% higher for a z-pin density of 1.5mm interval than for a z-pin density of 2.5mm interval. Employing z-pins as through-thickness reinforcements has advantages over a 3D weave.

不同分子量丙烯腈－丙烯酰胺共聚物溶液的流变性研究

WU Xue-ping, LING Li-cheng, LU Chun-xiang, WU Gang-ping, LI Yong-hong, LI Kai-xi, SONG Yan, ZHANG Rui, HE Fu

2004, 19(02): 103-108.

Abstract(2615)

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Abstract:
The rheological properties of poly(acrylonitrile-acrylamide) solutions with different molecular weights obtained by dissolving copolymers of acrylonitrile(AN) with acrylamide(AM) into dimethylsulfoxide (DMSO) were characterized by Non-Newtonian viscous index, activation energy of viscous flow, structure viscosity index and modulus. It is found that viscosities of the solutions with high molecular weight are more sensitive to shear rate and less sensitive to temperature than those with low molecular weight. The solutions with low molecular weight show better stability in repect of viscosity and elasticity than those with high molecular weight.

MCMB超细粉末特性及其成型工艺对烧结体性能的影响

LU Xiu-rong, WANG Cheng-yang, FAN Qi-ming

2004, 19(02): 109-113.

Abstract(2799)

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High-density isotropic carbons (HDIC) were prepared from ultra-fine MCMB powders with a particle size of 0.1～0.5μm, much less than that of 5～30μm used in former research. The influence of the nature of MCMB powders and molding conditions on the properties of HDIC were investigated by thermal analysis and SEM. It is found that HDIC sample with a bend strength up to 134.3MPa can be made by molding at 240MPa and carbonization at 1000℃. The excellent self-sintering property of the ultra-fine MCMB is ascribed to a large number of light molecules and some active groups adhering to the surface of MCMB. The hard agglomerates that have a bad effect on the microstructure and bend strength of HDIC originates from the self-sintering property of the ultra-fine MCMB. Grinding is an effective way to destroy hard agglomerates, and as a result improves the mechanical strength of HDIC. Due to the internal friction, tendency to agglomerate, and poor fluidity of ultra-fine MCMB powders, suitable molding pressure and especially holding time are necessary to obtain a homogeneous microstructure in the HDIC, and to alleviate the defects characterized by an inhomogeneous density distribution.

成型活性炭的制备及其甲烷吸附性能的研究

LI Jian-gang, LI Kai-xi, LING Li-cheng, HE Fu, LU Chun-xiang

2004, 19(02): 114-118.

Abstract(3437)

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The preparation and methane adsorption performance of formed activated carbon (FAC) prepared using carboxymethyl cellulose as a binder and powdered activated carbon with BET surface area of 2325m2/g as raw material were investigated. The orthogonal experiment indicated that the descending order of factors influencing the properties of the FAC is as follows: molding pressure > heat treatment temperature > heat treatment time > ratio of binder. The optimum condition to obtain highest volumetric methane uptake of 167.9 at 298K and 3.6MPa is 62.5MPa, 250℃, 90min and 20% for molding pressure, heat treatment temperature, heat treatment time and ratio of binder respectively.

短切炭纤维增强沥青基C/C复合材料的组织特征

GUO Ling-jun, LI He-jun, XUE Hui, SHI Zheng-hai, LI Ke-zhi

2004, 19(02): 119-123.

Abstract(3077)

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Abstract:
Short carbon fiber reinforced pitch-based carbon/carbon composites (SCFRC) with high density and low cost were fabricated under atmospheric conditions by a new and efficient mould pressing and semi-carbonization shaping technology. Microstructures and fracture morphologies of the SCFRC materials were observed using optical microscopy and SEM. The damage formation mechanism of short carbon fibers in mould pressing SCFRC materials was investigated, and an interface structural model between reinforcements (such as short carbon fiber and granular cokes) and carbon matrix in SCFRC materials was also proposed. Moreover, the findings indicate that both a matrix phase and a particle phase exist in SCFRC materials, and the particle phase is enwrapped by the matrix phase which has alayered structure like multiple orange peels. The orange-peel structure is similar to the parallel-oriented graphite structure on the surface of some carbon fibers.

酚醛纤维在热处理过程中微结构的变化

LIU Chun-ling, GUO Quan-gui, SHI Jing-li, LIU Lang

2004, 19(02): 124-128.

Abstract(2885)

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Phenolic fibers were prepared by melt-spinning a novolac resin and then crosslinking. Weight loss, FT-IR, X-ray analysis, SEM measurments, microporosity, electrical conductivity and tensile strength measurements were used to study the microstructure of phenolic fiber pyrolyzed at different temperatures. It is found that the BET surface areas exhibit a maximum value of 1040m2/g at 850℃ with heat treatment temperature (HTT) and micropores resulted from the paths left by volatiles formed at HTT between 450～900℃.

碳纳米管的表面修饰对Co-Mo催化剂HDS性能影响的研究

SHANG Hong-yan, LIU Chen-guang, XU Yong-qiang, ZHAO Hui-ji, SONG Huai-he

2004, 19(02): 129-136.

Abstract(4181)

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Abstract:
Multi-walled carbon nanotubes (MWCNT) were modified by concentrated nitric acid and the effect on surface acidity, dispersion of Co-Mo catalysts on them, and hydrodesulfurization (HDS) activity were respectively characterized by temperature-programmed desorption (TPD) and Boehm and mass titration, XRD and a flow micro-high pressure reactor using dibenzothiophene (DBT) as the sulfur-containing model compound. It is found that MWCNT is slightly basic and that modified MWCNT shows strong acidity with total amount of acid for 6 and 24h modified samples, M-MWCNT-6 and M-MWCNT-24 being 1.29×10-3 and 2.46×10-3 mol/g respectively. The dispersion of Co-Mo catalyst on MWCNT is significantly improved after the modification. The activity and selectivity for HDS are apparently higher for Co-Mo/MWCNT than for Co-Mo/Al2O3. For the modified samples, however, a slight and a significant decrease of activity and selectivity for HDS is observed for both Co-Mo/M-MWCNT-6 and Co-Mo/M-MWCNT-24 with a large proportion of byproduct found for the latter, indicating that significant modification is unfavorable for HDS.

用二胺在碳纳米管上引入胺基团的研究

CAO Chun-hua, LI Jia-lin, JIA Zhi-jie, CHEN Zheng-hua

2004, 19(02): 137-140.

Abstract(2978)

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Abstract:
The decoration of carbon nanotubes with amine groups by reacting with diamine was investigated by TEM, FT-IR and Raman spectroscopy after multi-walled carbon nanotubes (MWNTs) synthesized by chemical vapor deposition (CVD) had been purified and oxidized to contain carboxylate groups. It is found that the ends and side-walls of MWNTs are opened and oxidized into carboxylate group (σ(C=O)＝1709cm-1), and the amide-alkyl chain appears on the derivatives of the MWNTs (σ(C=O)＝1581cm-1) and the solubility of MWNTs in organic solvent is enhanced. The Raman results show that the D line and G line of MWNTs have no obvious changes before and after the reaction, which indicate that MWNTs retain their structure after the condensation reaction.

过渡金属Fe、Ni和Co对金刚石膜表面腐蚀作用的研究

LU Xian-yi, JIN Zeng-sun, HAO Shi-qiang, PENG Hong-yan, LIU Jian-she

2004, 19(02): 141-144.

Abstract(2401)

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Abstract:
Abstract: Diamond films were synthesized by electron enhanced CVD and hot cathode DC-PCVD, and the corrosive action of transition-metals Fe, Ni and Co on the surface was investigated using hot-filament heating under vacuum. The metals and the corroded surface of the diamond films were characterized by X-ray diffraction (XRD) and Raman spectroscopy. The corrosive effect of these transition-metals on the diamond films can be seen, with Fe having the largest effect. A non-diamond carbon phase was formed on the corroded surface of the diamond films and on the transition-metals, but transition-metal carbides were not found.

炭材料用作电吸附剂的研究与进展

FAN Li, ZHOU Yan-wei, YANG Wei-shen, YANG Feng-lin

2004, 19(02): 145-150.

Abstract(3253)

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Abstract:
Abstract: Electrosorption is an economic and efficient adsorptive process which is developed by a combination of electrochemistry with adsorption and separation technology. Four kinds of carbon materials used in electrosorption, including graphite, granular activated carbon, activated carbon fiber and carbon aerogel are investigated. This indicates that carbon is an excellent electro-adsorbent not only for inorganic ions but also for organic compound removal from aqueous or non-aqueous solutions.

功能性木质炭素新材料的研究与开发

HUANG Biao, GAO Shang-yu

2004, 19(02): 151-157.

Abstract(2267)

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Abstract:
Abstract: The study of wood charcoal utilization and development of advanced carbon materials from them has seen much activity in recent years. Efficient use of wood charcoal solves environmental and ecological problems by using wastes as raw materials. Progress in the research and utilization of wood charcoals, concerning the adsorption characteristics of wood charcoal, wood charcoal for environmental protection and advanced carbon materials from wood charcoals is summarized. Special attention is paid to advanced carbon materials from wood charcoal, such as: wood ceramics, wood oil adsorbents, electromagnetic interference shielding materials, electroconductive charcoal putty, titanium dioxide/charcoal composites, sintered charcoal, health care materials, soil modification materials, building materials, etc. The use of wood vinegar, a by-product of charcoal production, is also considered, such as for deodorizing incense, germicides, cosmetics, medical uses, food additives, agricultural chemicals, etc. Development of new advanced carbon materials from wood charcoal will produce many social, economic and ecological benefits.

刘朗研究员和他的研究活动

SHI Jing-li, SONG Jin-ren

2004, 19(02): 158-159.

Abstract(1386)

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Abstract:

2004 Vol. 19, No. 02

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