共查询到19条相似文献,搜索用时 78 毫秒
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碳纳米管具有管径小、长径比高的结构以及物理化学性能稳定等优良特性,被认为是真空冷阴极场发射电子源和场发射平板显示理想的阴极材料。加之碳纳米管兼具有机械强度高、韧性好等出众的力学性能,使其成为复合材料的理想添加相,将其与其他材料复合,可以制备出具有更加出众性能的复合材料。近年来有关碳纳米管及其复合材料场发射研究已成为一个备受关注的热点。概述了阴极场发射理论以及与碳纳米管场发射相关的几种场发射物理机制,介绍了碳纳米管复合场发射阴极的研究现状及制备方法,最后对碳纳米管复合阴极场发射的发展前景进行了展望。 相似文献
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以超声分散塬位聚合的方法制备出不同碳纳米管含量的碳纳米管,聚酰亚胺功能复合材料膜。通过对复合材料膜的拉伸性能、电性能、热性能和结晶行为进行表征,得到的实验结果表明:一定量碳纳米管的加入可对聚酰亚胺薄膜同时起到增强和增韧的作用,并降但对瓦的影响不明显。随碳纳米管含量增加,聚酰亚胺薄膜的表面电阻率和体积电阻率都有明显降低,并存在一个阈值;碳纳米管可起到结晶戍核剂的作用。 相似文献
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以三氯化铝(AlCl3)作催化剂,将多壁碳纳米管(MWNTS)悬浮在氯仿(CHCl3)溶液中,通过亲电加成反应,对MWNTS进行了侧壁化学修饰,并对化学修饰后的MWNTS作了红外光谱的分析.分别采用机械共混法和溶液共沉淀法制备了CPE/CNTs复合材料,对CPE/CNTs复合材料进行了拉伸性能及流变性能的测试,并利用扫描电子显微镜(SEM)观察了CPE/CNTs复合材料拉伸断面的形貌特征.结果表明:CPE/CNTs复合材料的拉伸强度随碳纳米管加入量的增加而增大,当碳纳米管的加入量为5份时,其拉伸强度最大,与纯氯化聚乙烯的拉伸强度相比,提高了75%;化学修饰后的碳纳米管在氯化聚乙烯基体中有了较好的分散性和相容性;CPE/CNTs复合材料的表观粘度随碳纳米管加入量的增加而逐渐增大. 相似文献
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超临界流体沉积法制备纳米Cu/SBA-15复合材料 总被引:2,自引:1,他引:1
采用超临界流体沉积法,以无机盐Cu(NO3)2为前驱物,超临界CO2为溶剂,乙醇为共溶剂,在压力20 MPa左右、温度 50℃ 条件下将Cu(NO3)2沉积到SBA-15介孔分子筛的孔道中。反应完成后,用氢气对前驱物进行还原,得到纳米线和纳米颗粒Cu/SBA-15复合材料。用透射电镜(TEM)和X射线衍射(XRD)对Cu/SBA-15复合材料进行表征,发现在SBA-15孔道内部填充了Cu 纳米线和分散的Cu 纳米颗粒。Cu 纳米线平均直径为6nm,长度为几纳米到几微米,并且沿着孔道生长,能够随着孔道发生弯曲;Cu纳米粒子的平均尺寸为3.2nm,高度分散。同时,实验中还发现,通过控制反应条件,能够控制复合材料中纳米结构的形貌(纳米线或者纳米颗粒) 。实验结果表明,超临界流体沉积法是制备担载型复合材料的有效方法。选择合适的共溶剂可以用超临界CO2溶解无机盐,并可以通过控制反应条件,控制所制备的复合材料中纳米结构的形貌。 相似文献
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A simple and efficient route has been employed to deposit noble metal nanoparticles (Pt, Ru, Pt-Ru, Rh, Ru-Sn) onto carbon nanotubes (CNTs) in supercritical methanol solution. In this method, the inorganic metallic salts acted as metal precursors, and methanol as solvent as well as reductant for the precursors. The as-prepared nanocomposites were structurally and morphologically characterized by X-ray diffraction spectroscopy, transmission electron microscopy (TEM), scanning electron microscopy, and X-ray photoelectron spectroscopy analyses. It was demonstrated that the CNTs were decorated by crystalline metal nanoparticles with uniform sizes and a narrow particle size distribution. The size and loading content of the nanoparticles on CNTs could be tuned by manipulating reaction parameters. Furthermore, the formation mechanism of the composites was also discussed. 相似文献
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为对比分析不同超临界流体对碳纤维/环氧树脂(CF/EP)复合材料的降解效果,首先,在间歇反应釜中通过超临界流体降解CF/EP复合材料,分析了不同反应温度下超临界CO2和超临界醇对CF/EP复合材料的降解能力,并提出了降解CF/EP复合材料的超临界流体选择方法;然后,采用单丝拉伸测试、SEM以及原子力显微镜等测试手段分析了超临界正丙醇和超临界正丁醇回收碳纤维的力学性能和微观形貌。结果表明:超临界CO2对CF/EP复合材料的降解能力较弱,正丙醇作为夹带剂时,降解效果有显著提高;超临界正丁醇对CF/EP复合材料的降解能力最强,其次为超临界正丙醇,超临界甲醇的降解能力最弱;选用的反应介质介电常数越小、偶极矩越大、溶解度参数与树脂基体越为接近,在超临界状态下CF/EP复合材料越容易降解。使用超临界流体降解CF/EP复合材料可以得到性能优异的碳纤维,与原始碳纤维相比,通过超临界正丙醇和超临界正丁醇回收的碳纤维单丝拉伸强度保持率在98%以上,且韦氏模数相近。 相似文献
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Pérez B Pumera M del Valle M Merkoçi A Alegret S 《Journal of nanoscience and nanotechnology》2005,5(10):1694-1698
A novel glucose biosensor based on a rigid and renewable carbon nanotube (CNT) based biocomposite is reported. The biosensor was based on the immobilization of glucose oxidase (GOx) within the CNT epoxy-composite matrix prepared by dispersion of multi-wall CNT inside the epoxy resin. The use of CNT, as the conductive part of the composite, ensures better incorporation of enzyme into the epoxy matrix and faster electron transfer rates between the enzyme and the transducer. Experimental results show that the CNT epoxy composite biosensor (GOx-CNTEC) offers an excellent sensitivity, reliable calibration profile, and stable electrochemical properties together with significantly lower detection potential (+0.55 V) than GOx-graphite epoxy composites (+0.90 V; difference deltaE = 0.35 V). The results obtained favorably compare to those of a glucose biosensor based on a graphite epoxy composite (GOx-GEC). 相似文献
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The potential usage of Copper (Cu) is very limited, where combined mechanical and thermal properties are desirable, which can be overcome by using carbon nanotube (CNT) as a reinforcement. An attempt was made to synthesize Cu/CNT composites by varying CNT diameter and its concentration through a molecular level mixing technique followed by uniaxial compaction and conventional sintering. The sintering behaviour of Cu and Cu/CNT composites was studied to understand the influence of different parameters. The sintering duration of Copper was decreased with an increase of CNT diameter. The maximum enhancement of properties was achieved at 0.25 wt.% CNT irrespective of its diameter, where the thermal conductivity and hardness were obtained as 328 W/mK at 20–40 nm diameter CNT composites and 81.2 ± 2.9 VHN at 40–60 nm diameter CNT composites, respectively. The conventional method of synthesize can generate the desired characteristics of composites at par with high end techniques, such as SPS. 相似文献
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Mihaela Baibarac Ioan BaltogSerge Lefrant Pedro Gomez-Romero 《Materials Science and Engineering: B》2011,176(2):110-120
Polydiphenylamine/single walled carbon nanotube (PDPA/SWNT) composites were synthesized electrochemically aiming at their application as active electrode materials for rechargeable lithium batteries. The electrochemical polymerization of diphenylamine (DPA) on a SWNT film immersed in a 1 M HCl solution was studied by cyclic voltammetry. Comparing cyclic voltammograms recorded on a blank Pt electrode with those obtained for a SWNT film deposited on Pt electrode one observes in the latter case a decrease of the DPA reduction potential. To elucidate electrochemical polymerization mechanism, photoluminescence studies on DPA/SWNT and PDPA/SWNT systems were carried out. Additional information concerning the functionalization process of SWNT with PDPA was obtained by Raman and IR spectroscopy. Using the PDPA/SWNT composite as active material for the positive electrode of a rechargeable lithium cell (LiPF6 electrolyte), the charge-discharge tests show a specific discharge capacity of ca. 245 mA h g−1, much higher than the 35 mA h g−1 for pure PDPA. 相似文献
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In this paper, we report a method based on nanosphere lithography technology for the synthesis of nano-pitched vertically aligned multi-walled carbon nanotube array. A monolayer of polystyrene nanospheres with diameter of 650 nm was coated on silicon oxide layer to create hexagonally arranged patterns. A metal layer, which acted as a catalyst for carbon nanotube growth, was deposited on the patterns by e-beam evaporation method. Nano-sized metallic patterns were formed by removing the polystyrene nanospheres. Uniform CNT arrays with pitch of 800 nm were successfully synthesized from the metallic patterns by plasma enhanced chemical vapor deposition. Using nanosphere lithography, the pitch of the single CNT array can be well-controlled. Therefore, the as-grown CNTs have potential applications in advanced interconnects technology and other nano applications. 相似文献
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以甲烷为碳源,通过化学气相沉积和化学蒸汽渗透两步法将热解炭填充至碳纳米管阵列间的空隙而制备出碳纳米管阵列/热解炭复合材料。采用扫描电镜和拉曼光谱仪对样品的结构进行表征。结果表明,碳纳米管被热解炭填充和覆盖形成均相的复合膜,其密度增加4倍,同时热解炭已石墨化。 相似文献
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O. Yu. Ivanshina M. E. Tamm E. V. Gerasimova M. P. Kochugaeva M. N. Kirikova S. V. Savilov L. V. Yashina 《Inorganic Materials》2011,47(6):618-625
Pt/CNT nanocomposite materials with an average platinum particle size of 3–5 nm and platinum content of 13–28 wt % have been
prepared by reducing chloroplatinic acid, H2PtCl6, in the presence of conical carbon nanotubes. The effect of synthesis conditions on the average platinum particle size, total
platinum content, and surface composition of the nanocomposites has been studied using X-ray photoelectron spectroscopy, IR
spectroscopy, electron microscopy, X-ray diffraction, and thermogravimetry. The materials have been tested as catalysts for
hydrogen oxidation and oxygen reduction. Their performance has been assessed by cyclic and steady-state voltammetric techniques.
The structure and composition effects on the electrocatalytic properties of the nanocomposites are discussed. 相似文献