亚胺基团对Schiff碱基过渡金属聚合物电化学性能的影响

采用化学合成法分别制备具有不同亚胺基团的单体Ni（salen）、Ni（salphen）,并分别配制成浓度为1 mmol/L单体溶液.在电化学工作站上,以制备好的碳纳米管电极片为工作电极,用循环伏安法进行电化学聚合得到对应的Schiff碱基过渡金属聚合物.用场发射扫描电镜观察聚合物的微观形貌,以及进行循环伏安法、恒流充放电法、交流阻抗谱测试.结果显示,聚合物poly[Ni（salen）]在碳纳米管层表面形成了带状聚合物,而聚合物poly[Ni（salphen）]沿着碳纳米管沉积生长.经测试得知：聚合物poly[Ni（salen）]和poly[Ni（salphen）]的最大电荷扩散系数分别为1.86×10-9 cm2/s、1.23×10-8 cm2/s,并且在0.05 mA/cm2下的比容量分别为66.6 F/g、106.3 F/g.具有亚胺苯环基团的Schiff 碱基过渡金属聚合物电化学性能较具有亚胺乙基基团的电化学性能更好.     

碳纳米管导电浆料的制备及其对LiNi0.8Co0.1Mn0.1O2 电化学性能的影响

用CVD法制备碳纳米管，通过强酸超声处理后溶解在N-甲基吡咯烷酮(NMP)中制备成碳纳米管导电浆料，利用XRD，SEM，BET考察了制备的碳纳米管导电剂浆料的结构和表面形貌，并考察了其作为导电剂对LiNi_0.8Co_0.1Mn_0.1O₂锂离子电池电化学性能的影响；研究结果表明经过王水处理后的碳纳米管获得了更好的分散性，并且得到了更多的介孔。添加了碳纳米管导电浆料的电池首次放电比容量是186.1 mAh/g，而未添加碳纳米管导电浆料的电池首次放电比容量是181.2 mAh/g。添加了碳纳米管导电浆料的电池循环性能更好，100次循环容量保持率是95.95%；添加了碳纳米管导电浆料的电池大倍率性能优越，在2C、3C、5C倍率下要明显高于单独用SP做导电剂的电池(1 C=180mA/g)。并且，添加碳纳米管导电浆料的电池电极界面阻抗要小。      

多壁碳纳米管表面邻二氯苯分子印迹聚合物材料的制备

在多壁碳纳米管表面接枝碳碳双键,以邻二氯苯为模板、苯乙烯为功能单体、乙二醇二甲基丙烯酸酯为交联剂,采用沉淀聚合技术,在碳纳米管表面制备邻二氯苯印迹材料,用红外光谱、热重分析、透射电镜对材料性能进行表征.结果表明,在碳纳米管表面接枝一层稳定、均匀、30～50 nm 厚的印迹材料.用高效液相色谱研究该印迹材料的吸附动力学及吸附容量,结果表明,印迹材料的吸附平衡时间为100 min,通过Scatchard分析,该聚合物与邻二氧苯的结合位点有2个,最大吸附容量为92.732 mol/g,平衡常数为17.986 mol/L,表明能成功将该材料用于检测环境中邻二氯苯的前处理.     

液相氧化法改性碳纳米管复合电极对钒电池性能的影响

为提升钒电池负极侧电极的电化学活性，采用液相氧化法对碳纳米管进行改性，并将其引入石墨毡表面制备复合电极。首先对碳纳米管与石墨毡的电化学性能进行对比，再通过液相氧化改性对碳纳米管的电化学活性进一步优化，最后制备了碳纳米管石墨毡复合电极，并采用充放电测试考察其性能表现。结果表明：在浓H2SO4与浓HNO3体积比为1︰3，温度80 ℃，改性时间2 h条件下得到的碳纳米管电化学活性最佳。在120 mA/cm2的电流密度下，以复合电极为负极的电池电压效率和能量效率分别为87.96%、83.47%，分别比石墨毡（82.08%、77.31%）提高了5.88和6.16个百分点，具有良好的倍率性能。     

粉末冶金在CNTs增强金属基复合材料中的应用

碳纳米管(CNTs)具有优异的力学和物理化学性能,是理想的复合材料增强体之一。综述了近几年国内外通过粉末冶金方法进行CNTs增强金属基复合材料制备的应用,阐述了用粉末冶金法制备CNTs/金属基复合粉末和块体材料的进展,最后对其应用前景进行了展望。     

碳纳米管增强铝基复合材料的力学和物理性能

采用磁力搅拌与放电等离子烧结技术制备了碳纳米管(CNT)增强铝基复合材料.对试样进行了扫描电镜和透射电镜表征,测试了试样的力学性能、摩擦性能、电学性能和热学性能.当碳纳米管在试样中的质量分数为1%时,可在铝基体中均匀分布且CNT/Al界面结合良好,此时试样的抗拉强度和硬度较纯A1分别提高了29.4%和15.8%.在获得最佳力学性能强化和最佳减磨效果的同时.试样电导率较纯Al仅降低8.0%.碳纳米管可提高基体的热导率.但强化效果不明显.      

热处理对铜基碳纳米管复合镀膜结构和性能的影响

研究热处理工艺参数对铜基碳纳米管复合薄膜的微观结构和性能的影响,采用超声辅助脉冲电流复合电沉积法在不锈钢基板上沉积制备铜基碳纳米管复合镀膜,再将制备的复合薄膜在H2中进行热处理.利用X射线衍射谱仪(XRD)、场发射扫描电子显微镜(SEM)以及四探针电阻率仪等对热处理后的铜基碳纳米管复合镀膜进行了测试.结果表明,随着热处理温度和时间的变化,复合铜膜的结构、形貌及性能也相应变化;当热处理参数为400℃×2 h时,铜基碳纳米管薄膜的各项性能最佳.     

冷固结球团用地聚合物黏结剂制备参数优化

 针对目前广泛使用的冷固结球团黏结剂高温下失效的缺点，提出使用地聚合物体系材料作为黏结剂，以保证球团的高温性能。首先使用化学分析、X射线衍射分析、红外光谱等方法对地聚合物黏结剂原料性能进行分析；随后制备偏高岭土-水玻璃地聚合物体系黏结剂并进行冷固结压块，分别研究黏结剂制备过程中参数养护温度、养护时间、n（H2O）/n（Na2O）、n（Na2O）/n（SiO2）和n（SiO2）/n（Al2O3）对球团冷态抗压强度的影响，得出此黏结剂制备最佳参数；最后探讨了地聚合物黏结剂球团高温强度演变规律。结果表明，将最优条件下制备的黏结剂应用于冷固结球团，强度可达402.3 N/个 ，满足生产要求；在惰性气氛下，地聚合物黏结剂压块强度随温度升高而升高，且高温下强度增加幅度变大，这表明地聚合物黏结剂在高温下不会失效，且高温有利于黏结剂抗压强度增加。     

碳纳米管增强Cu基和Al基复合材料界面改性

在碳纳米管(carbon nanotubes,CNTs)增强Cu基和Al基复合材料的制备中,界面改性是提高复合材料性能的重要方法。金属基体和碳纳米管间的有效界面结合直接影响了复合材料中界面的载荷传递、导电以及导热性能,从而影响复合材料性能。本文综述了近几年碳纳米管增强Cu基和Al基复合材料界面改性的工艺方法,讨论了界面改性工艺对碳纳米管增强Cu基和Al基复合材料界面结构和性能的影响。     

聚合物/蒙脱石纳米复合材料的研究进展

聚合物/蒙脱石纳米复合材料是矿物材料与高分子工程技术交叉、融合的结晶,近十年来已成为研究热点之一。由于其结构、形态等与常规聚合物复合材料存在差异,使其具有更优异的物理力学性能、耐热性和气体液体阻隔性能等,在橡胶、塑料等领域已经获得初步应用并显示出巨大的潜在应用前景。本文对聚合物/蒙脱石纳米复合材料的种类、制备和应用研究现状进行了综述,指出了聚合物/蒙脱石纳米复合材料研究中存在的问题和应努力的方向。     

Influence of addition of nanoclay on the mechanical behavior of polymer nanocomposite

The mechanical behavior of polymer nanocomposites, which containing epoxy resin as matrix and carbon fiber, glass fiber, nanoclay as reinforcements have been studied. The composites were prepared by melt stirring method. Scanning Electron Microscope (SEM) studies show that the nanoclay particles within the epoxy resin were orderly exfoliated. A compound containing carbon fiber (C_f =2wt %), glass fiber (G_f =3wt %), nanoclay (NC=0.5wt %) in epoxy matrix give a superior properties, when compared with other polymer nanocomposite compounds. The enhancement of mechanical properties is due to the good dispersion of nanoclay and large L/D ratio of fibers and more numbers of interfaces created by the inclusions of nanoclay.     

Influence of Multiwalled Carbon Nanotubes on the Aging Behavior of AA 6061 Alloy Matrix Nanocomposites

The effect of multiwalled carbon nanotubes (MWCNT) with varying volume fractions on aging behavior of aluminium alloy 6061 matrix nanocomposites (MWCNTs/AA 6061) has been studied. The aging behavior of the developed nanocomposites has been evaluated at a temperature of 170 °C for different time intervals by means of Vickers hardness. Increase in the peak hardness by 32 and 27 % was observed by the addition of 2 wt% copper coated and uncoated MWCNTs for the aging time of 40 and 43 min as compared to base alloy with the peak hardness of 107 for the aging time of 55 min. The dramatic increase in the peak hardness of the nanocomposite within a short span of aging time is due to the generation of dislocations due to the difference in the co-efficient of thermal expansion between the AA6061 matrix and MWCNTs.     

Crack Bridging in Polymer Nanocomposites

Carbon nanotube reinforced composites offer enhancements in fracture properties since the reinforcing nanotubes provide a bridging mechanism to resist crack growth. In this paper, a study of crack bridging by nanotubes in a nanotube-reinforced polymer composite is presented. The process of crack bridging is idealized as normal pullout of the participating nanotubes from the polymer matrix. The resistance to crack growth due to bridging is taken as the aggregate of the resistance offered by all the nanotubes, ignoring any interaction among the nanotubes themselves. The pullout of a single nanotube from the polymer matrix is modeled as an axisymmetric, nearly one-dimensional problem. This is done by assuming that fracture along the nanotube–polymer interface is dominated by shear openings, and that the nanotube behaves as a rigid body. When the polymer is a linear elastic material, the force–displacement relation for pullout is obtained as a function of dimensionless variables representing the interfacial fracture energy and the pullout length scale. Applying the correspondence principle, the elastic results are extended to the case where the polymer is a linear viscoelastic material with a single relaxation time. The force–displacement relation is then a function of the viscoelastic properties of the polymer and the pullout velocity as well. Using these results, the apparent enhancement in the fracture energy of the composite is obtained. This provides a guideline to design these composites for desired fracture properties in terms of the interfacial strength of the nanotube–polymer interface and the volume fraction of the nanotubes. Results of numerical simulations of nanotube pullout are compared to the predictions of the analytical model.     

Mechanical-Thermal-Electrical and Morphological Properties of Graphene Reinforced Polymer Composites: A Review

Grephene is a substance composed of pure carbon with atoms arranged in a regular hexagonal pattern similar to graphite, but in a one-atom thick sheet. It is very light, with a 1-square-meter sheet weighing only 0.77 mg. It is the basic structural element of some carbon allotropes including graphite, charcoal, carbon nanotubes and fullerenes. It has considerable interest over recent years due to its intrinsic mechanical, thermal and electrical properties. Incorporation of small quantity of graphene fillers into polymer can create novel nano-composites with improved structural and functional properties. Recent investigation clearly confirmed that graphene-polymer nano-composites are promising materials with applications ranging from transportation, biomedical systems, sensors, electrodes for solar cells and electromagnetic interference. This review discusses the different methods of manufacturing graphene based composites and also compiles their electrical, mechanical and thermal properties. Many references to the latest work on properties and processing have been cited in this review.     

Improving Anodes for Lithium Ion Batteries

As energy demands increase for applications such as automotive, military, aerospace, and biomedical, lithium-ion battery capacities are forced to increase in a corresponding manner. For this reason, much research is directed toward the development of improved battery anodes. Carbon nanotubes (CNTs), silicon, tin, and nanocomposites with these metals are the leading candidates for the next generation of lithium-ion battery anodes, leading to capacities 3 to 10 times that of graphite alone. This review looks at some of the studies addressing high capacity lithium-ion battery anodes.     

不同纳米相增强铜基复合材料的性能

采用粉末冶金法,制备纳米SiO2颗粒(n-SiO2)、纳米SiC晶须(n-SiCw)和碳纳米管(CNTs)3种不同形态纳米相增强铜基复合材料,通过光学显微镜(OM)、扫描电镜(SEM)和球/盘式摩擦磨损试验机等测试手段研究纳米添加相对铜基复合材料显微组织、物理性能和摩擦学性能的影响。结果表明,纳米相可以显著提高铜基复合材料的硬度,其中n-SiCw的增强效果优于n-SiO2和CNTs;CNTs/Cu的减摩耐磨效果优于SiO2/Cu和SiCw/Cu;0.75%-CNTs/Cu(质量分数)复合材料具有高的硬度、优良的减摩耐磨性能,是综合性能最佳的复合材料。     

纳米碳管铝基复合材料组织与性能的研究

试验采用搅拌铸造法制备了纳米碳管增强铝基复合材料,对其显微组织、硬度、抗拉强度和电阻率进行了研究.结果表明:纳米碳管的加入能够细化复合材料晶粒,表面镀铜后可以抑制基体与增强体之间的界面反应,避免脆性碳化物的生成;复合材料的硬度和抗拉强度随着纳米碳管加入量的增加先增加后减小,纳米碳管的质量分数为1.0%时,达到最大值,与基体相比分别增加了34.8%和34.4%;纳米碳管的加入对基体的导电性影响不大.     

Buckling of Multiwalled Carbon Nanotubes Using Timoshenko Beam Theory

A Timoshenko beam model is presented in this paper for the buckling of axially loaded multiwalled carbon nanotubes surrounded by an elastic medium. Unlike the Euler beam model, the Timoshenko beam model allows for the effect of transverse shear deformation which becomes significant for carbon nanotubes with small length-to-diameter ratios. These stocky tubes are normally encountered in applications such as nanoprobes or nanotweezers. The proposed model treats each of the nested and concentric nanotubes as individual Timoshenko beams interacting with adjacent nanotubes in the presence of van der Waals forces. In particular, the buckling of double-walled carbon nanotubes modeled as a pair of double Timoshenko beams is studied closely and an explicit expression for the critical axial stress is derived. The study clearly demonstrates a significant reduction in the buckling loads of the tubes with small length-to-diameter ratios when shear deformation is taken into consideration.     

十二烷基硫酸钠对碳纳米管悬浮液分散性能的影响

以十二烷基硫酸钠(SDS)为分散剂,制备碳纳米管悬浮液。通过测定SDS在碳纳米管表面的等温吸附曲线和悬浮液的Zeta电位,研究SDS对碳纳米管表面性质的影响。结果表明:SDS的加入使Zeta电位由-28 mV变为-48 mV左右,SDS浓度c(SDS)为2.0×10-3 mol/L左右时达到最大电位值并最终趋于稳定;SDS在碳纳米管表面的等温吸附曲线为典型的双平台型(LS型)吸附曲线。SDS吸附量在低浓度下(0.7×10-3~1.2×10-3 mol/L范围内)处于第一平台吸附值;随后SDS浓度进一步增大,吸附量迅速上升,在2×10-3 mol/L处趋近饱和吸附,吸附量达到第2个平台。悬浮碳纳米管浓度测定结果表明SDS可作为水性体系碳纳米管的分散剂,SDS的最佳浓度范围为2.0×10-3~8.0×10-3 mol/L,通过静电排斥和位阻效应有效阻止碳纳米管的团聚。