多壁纳米碳管／Cu基复合材料的摩擦磨损特性

利用销－盘式磨损试验机研究了粉末冶金法制备的多壁纳米碳管／Cu基复合材料的稳态摩擦磨损行为,并用扫描电镜分析了复合材料的磨损形貌。结果表明：多壁纳米碳管／Cu基复合材料具有较小的摩擦系数,并随纳米碳管质量分数的增加而逐渐降低;由于复合材料中纳米碳管的增强和减摩作用,在低载荷和中等载荷作用下,随着纳米碳管质量分数的增加,复合材料的磨损率减小;而在高载荷作用下,由于发生表面开裂和片状层剥落,含纳米碳管质量分数高的复合材料的磨损率增高。     

Conducting and magnetic behaviors of polyaniline coated multi-walled carbon nanotube composites containing monodispersed magnetite nanoparticles

High conductivity and supermagnetism of polyaniline (PANI)-coated multi-walled carbon nanotube (MWCNT) composites containing monodispersed 6 nm iron oxide (Fe₃O₄) nanoparticles has been successfully synthesized by in situ chemical oxidative polymerization using anionic surfactant dodecylbenzenesulfonic acid sodium salt. Hydrophilic 6 nm spherical Fe₃O₄ nanoparticles fabricated by the thermal decomposition process were chemically modified using 11-aminoundecanoic acid tetramethylammonium salt. The modified nanoparticles were further mixed with carboxylic acid containing multi-walled carbon nanotubes (c-MWCNTs) in an aqueous solution to form one-dimensional Fe₃O₄ coated c-MWCNT template and PANI/c-MWCNT nanocomposite were then synthesized via in situ chemical oxidative polymerization in HCl solution. Structural and morphological analysis using FESEM, HRTEM and XRD showed that the fabricated Fe₃O₄ coated c-MWCNT/PANI nanocomposites are one-dimensional core (Fe₃O₄ coated c-MWCNT)–shell (PANI) structures. The electrical conductivity of 1 wt% Fe₃O₄ coated c-MWCNT/PANI nanocomposites at room temperature is 37.7 S/cm, which is decreased to 28.6 S/cm with the loading of 5 wt% Fe₃O₄ nanoparticles. The magnetic properties of Fe₃O₄ coated c-MWCNT/PANI nanocomposites exhibit supermagnetism with saturation magnetization in the range of 0.04–0.15 emu/g, which increases as the amount of Fe₃O₄ nanoparticles increases.     

碳纳米管/四氧化三铁复合材料的磁性能和电催化性能

采用水热法制备碳纳米管(MWCNT)/四氧化三铁(Fe3O4)复合材料,运用透射电子显微镜(TEM)、X射线衍射(XRD)、傅立叶红外吸收光谱(FTIR)、振动样品磁强计(VSM)以及循环伏安法等对复合材料的微观结构、磁性能以及电化学行为进行研究和分析。结果表明:在MWCNT/Fe3O4复合材料中,磁性Fe3O4纳米颗粒能够对MWCNTs表面较好的包覆,实现了Fe3O4对MWCNTs的表面修饰;Fe3O4含量(质量分数)为62.5%的复合材料容易被磁化,常温下其饱和磁化强度(Ms)为35.89 A·m2/kg,矫顽力(Hc)为0.19 A/m,表现出良好的顺磁性;MWCNTs/Fe3O4修饰玻碳(GC)电极对H2O2的电化学响应具有良好的促进作用,使其氧化还原过电位升高,氧化峰值电流显著增强。     

多壁碳纳米管/壳聚糖复合材料的制备及电催化性能

采用混酸法制备羧基化多壁碳纳米管以及采用超声凝聚法制备壳聚糖纳米粒子,再通过静电自组装的方法制备碳纳米管/壳聚糖(相对分子质量(Mr)不小于5万和不小于10万)、碳纳米管/高密度壳聚糖、碳纳米管/羧化壳聚糖、多壁碳纳米管/壳聚糖盐酸盐复合材料。通过SEM、HRTEM及XRD对产品进行微观结构分析,利用循环伏安法对H2O2在碳纳米管/壳聚糖修饰电极上的电化学行为进行研究。结果表明:壳聚糖盐酸盐对碳纳米管具有较好的包覆效果,包覆层厚度约为3.5nm,静置12h后具有良好的溶液分散性;碳纳米管/壳聚糖盐酸盐修饰玻碳电极改善了H2O2的氧化还原电流,同时还降低了H2O2的氧化还原的过电势,对其电化学催化性能具有良好的促进作用。     

Structural interpretations of deformation and fracture behavior of polypropylene/multi-walled carbon nanotube composites

The deformation and crack resistance behavior of polypropylene (PP) multi-walled carbon nanotube (MWNT) composites have been studied and their interrelation to the structural attributes studied by transmission electron microscopy (TEM), atomic force microscopy (AFM), scanning electron microscopy (SEM), wide-angle X-ray diffraction (WAXD), differential scanning calorimetry (DSC) and polarization light microscopy has been discussed. The composites were produced from industrial available MWNT by extrusion melt-mixing and injection-molding. In stress–strain measurements a strong increase in the yield stress and the Young’s modulus at low MWNT contents has been observed, which was attributed to an efficient load transfer between the carbon nanotubes and polypropylene matrix through a good polymer–nanotube adhesion as indicated by SEM. The extent of enhancement in mechanical properties above 1.5 wt.% of MWNT decreased due to an apparently increased tendency of clustering of carbon nanotubes. Several theoretical models have been taken into account to explain the mechanical properties and to demonstrate the applicability of such models to the system under investigation. The crack resistance behavior has been studied with the essential work of fracture (EWF) approach based on post-yield fracture mechanics (PYFM) concept. A maximum in the non-essential work of fracture was observed at 0.5 wt.% MWNT demonstrating enhanced toughness compared to pure PP, followed by a sharp decline as the MWNT content was increased to 1.5 wt.% reveals a ductile-to-semi-ductile transition. Studies on the kinetics of crack propagation aspects have revealed a qualitative picture of the nature of such a transition in the fracture modes.     

ZrB2-MoSi2/SiC涂层C/C复合材料的制备及氧化性能（英文）

为了提高C/C复合材料的抗氧化性,在C/C复合材料基体上制备了ZrB2-MoSi2/SiC涂层。采用包埋法制备SiC中间层,采用喷涂法制备ZrB2-MoSi2外涂层。用XRD和SEM分别分析、测试所制备涂层的物相组成和显微结构,研究涂层复合材料的高温抗氧化性能。结果表明:C/C复合材料的外涂层由ZrB2、MoSi2和SiC三相组成;在1273K和1773K下分别氧化30h和10h后ZrB2-MoSi2/SiC涂层试样的质量损失分别为5.3%和3.0%,涂层表面长有纳米SiC晶须。C/C复合材料ZrB2-MoSi2/SiC涂层具有自愈合特性和良好的高温抗氧化性能。     

Bent-shape effects of multi-walled carbon nanotube on the electrical conductivity and rheological properties of polycarbonate/multi-walled carbon nanotube nanocomposites

In this study, polycarbonate (PC)/multi-walled carbon nanotube (MWCNT) nancomposites have been prepared by pretreating MWCNT solutions with ultrasonication. We demonstrate that the electrical conductivity and rheological properties of PC/MWCNT nanocomposites strongly depend on the mesoscopic shape factor (l_sp/d), which is represented by the ratio between the static bending persistence length (l_sp) and outer diameter (d) of the MWCNT. The electrical conductivity of PC/MWCNT nanocomposites increases linearly with increasing (l_sp/d)² and the percolation threshold of PC/MWCNT nanocomposites decreases linearly with increasing (l_sp/d)² of MWCNTs. The storage modulus of PC/MWCNT nanocomposites increases linearly with increasing (l_sp/d)² of MWCNTs at all frequency ranges.     

Preparation and characterization of Mo/Al2O3 composites

In order to improve the performance of molybdenum, the Mo/Al₂O₃ composites were prepared by using a hydrothermal method for the synthesis of the precursor powders and subsequent powder metallurgical processing. The morphologies of the composite powders and the microstructures and properties of the composites were investigated. Compared with the pure Mo powder, the grains of composite powders are smaller because of the existence of the fine Al₂O₃ particles. The results from the sintered composites show that the fine Al₂O₃ particles are evenly distributed in the Mo matrix and well bonded with the Mo matrix. With increasing Al₂O₃ content, all the values of the micro-hardness, compressive strength and flow stress at 0.08 strain are increased. The strengthening effect is more remarkable at elevated temperatures. At room temperature, the compressive strength and the flow stress at 0.08 strain of the composite with 40 vol.% Al₂O₃ are 1.67 and 2.01 times greater than those of pure molybdenum, respectively, while the values are up to 2.02 and 2.52 at 1100 °C.     

An electrochemical study of the synthesis and properties of multi-walled carbon nanotube/poly ortho aminophenol composites

Composites of multi-walled carbon nanotubes (MWCNTs) and poly ortho aminophenol (POAP) with good uniformity for use as electrodes in electrochemical capacitors were prepared by electropolymerization by using the ionic surfactant as electrolyte, for dispersing CNTs within conducting polymer/carbon nanotube composite films. The capacitance properties were investigated with cyclic voltammetry (CV), discharge tests and ac impedance spectroscopy. The composite electrode shows much higher specific capacitance, better power characteristics and is more promising for application in the capacitor than a pure POAP electrode. The effect and role of MWCNT in the composite electrode are discussed in detail. In comparison with a Ni–POAP/glassy carbon (GC), a Ni–MWCNT–POAP/GC electrode shows a better catalytic performance for the electrocatalytic oxidation of methanol.     

碳纳米管铜基复合颗粒的制备

采用混酸纯化法在碳纳米管表面引入羟基和羧基等基团.利用明胶使碳纳米管均匀地分散在五水硫酸铜溶液中,用葡萄糖在碱性条件下还原得到氧化亚铜内嵌碳纳米管复合颗粒,将其还原获得铜基内嵌碳纳米管复合颗粒.SEM和TEM观察结果表明碳纳米管均匀地分布在几百纳米至1μm的复合颗粒中.XRD分析表明得到的产物是纯净的Cu2O和Cu颗粒.复合球形貌影响因素研究发现明胶在复合物成球过程中起着关键性的作用,明胶与CNTs质量比为5～7时配比效果最佳.     

Co包覆纳米Al2O3/TiC复合材料的制备及其显微结构研究

采用Co包覆Al2O3/TiC纳米级粉料进行了不同Co含量、不同烧结温度的热压烧结实验。对综合力学性能最佳的nATC8复合材料进行了工艺参数的优化,得出其优选工艺参数为,烧结温度1650℃,保温30min,热压30MPa。采用优选工艺参数制备的纳米复相陶瓷材料的硬度为92.7HRA,弯曲强度fσ为782MPa,断裂韧性KIC为7.81MPa.m1/2。通过对其断口的观察,发现形成了晶内型结构,并观察到了裂纹曲折的扩展路径以及裂纹的分叉、偏转、桥联,这些有助于材料强度和韧性提高的现象。     

Sb_2O_3/聚氯乙烯复合材料的制备及阻燃性能

以聚氯乙烯(PVC)为基体,微米级和纳米级Sb2O3为阻燃剂,采用熔融共混的方法制备了Sb2O3/PVC复合材料。分别利用扫描电子显微镜(SEM)和X射线能量色散谱仪(EDS)对复合材料和燃烧产物的形貌进行表征,通过极限氧指数仪(LOI)和垂直燃烧实验对复合材料的阻燃性能进行了研究。结果表明:与纯PVC相比,Sb2O3/PVC复合材料能够形成有效的Sb-Cl阻燃体系,对软质PVC塑料的阻燃性能有明显的提升;相比于微米Sb2O3,纳米Sb2O3由于其粒径的优势,使其与PVC基体的相容性更好,同时增大了燃烧区Sb2O3分解反应的平衡常数,生成了更多的Sb Cl3和Sb OCl,相应的也促进了气相中活性自由基捕获反应的进行,从而使得燃烧更容易被终止;纳米Sb2O3与PVC的质量比为1.85∶100时,Sb2O3/PVC复合材料可达到难燃级别,氧指数和UL-94等级分别为27.1%和V-1级;而微米Sb2O3与PVC的质量比为3∶100时,Sb2O3/PVC复合材料才可达到难燃级别。     

Behavior of mixed multi-walled carbon nanotube/P3HT monolayer at the air/water interface

The sidewall structure of multi-walled carbon nanotubes (MWNTs) was successfully functionalized with poly(3-hexylthiophene) (P3HT) by a non-covalent bond method. P3HT plays an important role in dispersing MWNTs, and assists them to have a stable existence at the air/water interface. The behavior of mixed MWNT/P3HT monolayer at the air/water interface was investigated after obtaining a homogeneously dispersed solution. The effect of MWNT concentration on the mixed MWNT/P3HT monolayer was investigated using the pressure–area (π–A) isotherm, relaxation curve and transmission electron microscopy (TEM). The mixed MWNT/P3HT monolayer was transferred onto a solid substrate using the Langmuir–Blodgett (LB) technique with horizontal or vertical deposition. The multilayer film was delicately fabricated by repeated deposition of the ultra-thin film. Scanning electron microscopy (SEM) images revealed non-uniformity in morphology of the ultra-thin MWNT/P3HT films. The absorption intensity at 250 nm by UV/vis spectroscopy illustrates that a uniform formation of mixed MWNT/P3HT monolayer into multilayer film was successfully obtained by horizontal deposition. The current–voltage characteristic of the ultra-thin MWNT/P3HT film shows that the current increases linearly with the increasing voltage, which indicates that MWNT/P3HT film forms an ohmic contact with gold. And, the electric current was estimated to be mainly contributed by MWNTs.     

Multiwalled carbon nanotube/polyaniline thermoreversible gel composites

Composites of multiwalled carbon nanotubes (MWCNTs) in a dinonylnaphthalene disulphonic acid (DNNDSA)-doped polyaniline (PANI) thermoreversible gel were prepared from a formic acid medium. A three-dimensional fibrillar network and a reversible first order phase transition characterize the systems as thermoreversible gels. Transmission electron micrographs indicate that the MWCNTs are well dispersed in the gel and PANI-DNNDSA wraps the MWCNT surface unevenly. π–π, CH–π and acid–base interactions are evident from Fourier transform infrared spectroscopy. Thermal stability increases with increasing MWCNT content and the storage modulus of the composites increases dramatically. Photoluminescence increases significantly in the composites showing a red shift of the emission peak with increasing MWCNT content. The π band-polaron band transitions show a red shift and the dc conductivity increases two orders of magnitude over that of the PANI-DNNDSA gel with the addition of MWCNTs. The current–voltage characteristic curves are Ohmic in nature and the current increases appreciably with increasing MWCNT concentration.     

Processing and characterization of carbon nanotube mat/epoxy composites

A carbon nanotube mat (CNT mat) with long (∼1 mm) multi-walled carbon nanotubes (MWCNTs) was used to process MWCNT/epoxy composites at high concentrations (4.4 and 10.0 wt.%) of MWCNTs by a simple method without the use of a solvent. The CNT mat circumvents several cumbersome processing steps, including the dispersion of CNTs in a solvent. Two different resin-impregnation processing methods were explored. The processing steps were chosen to prepare composite samples based on the performance of the composites and the simplicity of the processing techniques. Scanning electron microscopy (SEM) was used to examine the microstructures of the CNT mat and its composites. The mechanical and electrical properties were tested. The tensile strengths of the composites with 10.0 wt.% MWCNTs were increased by 17% to 90% when compared to that of neat epoxy samples. The electrical conductivity of the composite is 36.1 S/cm. 4.4 wt.%-MWCNT composites show very large strain valuesupon fracturing (> 15 %), and their electrical conductivity is 14.9 S/cm. These results show that CNT mat/epoxy composites can be used as flexible electrodes and as a matrix system for advanced fiber composites.     

以MOFs为前驱体制备二维碳带/Al2O3及氮掺杂碳带/Al2O3去除高氟废水

以2D-MOFs为前驱体,采用溶剂热法合成铝基金属有机骨架MIL-53(Al),采用煅烧法合成2D碳带/Al2O3.为了解氟在碳带/Al2O3和氮掺杂碳带/Al2O3上的吸附行为,对吸附参数如pH、液固比、吸附动力学、吸附热力学和阴离子竞争等进行研究.碳带/Al2O3对氟的吸附为化学吸附和多层吸附;而氮掺杂碳带/Al2...     

Polyaniline and multi-walled carbon nanotube composite electrode for rechargeable battery

The multi-walled carbon nanotube was introduced into the polymer matrix (PANI) to improve the electric conductivity as well as mechanical properties of the original polymer matrix.PANI/multi-walled carbon nanotube (MWCNT) composites were synthesized via ex-situ and in-situ polymerization to improve their electrical property.And the DC conductivities of PANI/MWCNT according to content and diameter of MWCNT were measured by four-point probe.The highest electric conductivity of PANI/MWCNT composite is 20 S/cm when 0.3% (mass fraction) MWCNTs with 10 nm in diameter and 15 μm in length are added in composite.     

原位生长碳纳米管对炭/炭复合材料导热性能的影响

以炭纤维表面原位生长有碳纳米管(Carbon nanotubes,CNTs)的针刺毡体作为前驱体制备出生长有CNTs的炭/炭复合材料,并与在同样工艺条件下通过致密化最终热处理得到的纯炭/炭复合材料进行对比.结果表明,在密度几乎相同的情况下,生长有CNTs的炭/炭复合材料的室温Z轴热导率约为11.10 W/(m·K),几乎为纯炭/炭复合材料的室温Z轴热导率(6.28 W/(m·K))的2倍,其原因可能在于CNTs可以有效改善炭纤维和热解炭之间的界面特性,明显减少炭/炭复合材料中纤维和热解炭界面处周裂纹的出现,还可以诱导热解炭形成一种拥有更高导热率更易石墨化的粗糙结构.     

In-situ electrochemical polymerization of multi-walled carbon nanotube/polyaniline composite films for electrochemical supercapacitors

Multi-walled carbon nanotube (MWCNT)/polyaniline (PANI) composite films were prepared by in-situ electrochemical polymerization of an aniline solution containing different MWCNT contents. The supercapacitive behaviors of these films were investigated with cyclic voltammetry (CV), charge–discharge tests, and ac impedance spectroscopy. The results revealed that the MWCNT/PANI films show much higher specific capacitance (SC), better power characteristic, better cyclic stability, and more promising for applications in supercapacitors than a pure PANI film electrode. The highest specific capacitance value of 500 F g^?1 was obtained for the MWCNT/PANI composite film containing MWCNT of 0.8 wt.%. The improvement mechanisms of the capacitance of the composites are also discussed in detail.