硫化异丁烯填充碳纳米管的机理研究

利用液相湿化学法制备了润滑添加剂硫化异丁烯(T321)填充的碳纳米管(CNTs)复合物。首先利用浓酸对CNTs进行开口以及截短化处理,处理后的CNTs的端帽被打开,T321在液相条件下通过毛细作用进入开口CNTs中;然后利用透射电子显微镜、X射线光电子能谱、差热-热重分析、红外光谱等测试手段对复合物的化学成分、形态结构进行表征。实验结果表明,通过液相湿化学法可以得到T321填充的CNTs,在填充过程中二者主要发生物理结合。T321可通过毛细作用渗入CNTs内,二者形成复合物后,CNTs可对其中的T321起保护作用,T321填充CNTs的填充率约25%。     

纳米流体在摩擦领域中的应用

为了寻找更好的润滑剂使机械零件的磨损最小化,人们尝试把纳米材料加入到基础润滑油里形成的纳米流体,与传统的润滑油相比,该流体具有更好的减摩抗磨性能。文中介绍了纳米流体的制备方法,包括单步法及两步法,并评价了各自的优缺点;详细论述了多种纳米颗粒添加剂对基础润滑油摩擦学性能的影响;指出了纳米流体后续研究中需要注意的一些问题。     

微波辅助加热法在泡沫镍表面生长纳米碳管

以酸处理过的泡沫镍为催化剂前驱体及辅热材料,以菲为碳源,使用微波辅助加热法,短时间内在泡沫镍表面及内孔生长管径分布均匀、长径比较大的纳米碳管(CNTs)。使用扫描电子显微镜(SEM),X射线衍射仪(XRD)对所得产物的微观形貌和结构进行表征,并研究泡沫镍的结构、前处理用酸浓度、微波加热时间等对制备的CNTs的影响,最后提出了CNTs的生长机理。结果表明:酸浓度为6mol·L~(-1),微波时间为30s时,所得碳纳米管管径约为30nm,长度可达微米级。     

纳米级Au/C催化剂的制备及其DBFC单池性能

采用金溶胶负载法分别在CNTs、Vxc-72R炭黑和ECP 600JD科琴炭黑上负载了平均粒径约为5.0nm且尺寸分布均匀的纳米金颗粒,考察了酸处理对炭载体的影响及不同Au/C催化剂对BH4-电催化活性的影响.结果显示:经过酸处理三种炭载体的表面亲水性提高,其中CNTs的BET比表面积提高,而Vxc-72R和ECP 600JD的BET比表面积降低.炭载体负载纳米Au的能力与其BET比表面积密切相关.对炭载体进行酸处理可大幅度提高Au/C催化剂对BH4-的电催化性能,其中金负载在经酸处理的ECP 600JD炭黑上显示出最佳的电催化性能.     

碳纳米管掺杂ZnO复合材料的乙醇气敏特性研究

采用简单的一步式水热法制备了颗粒状纳米ZnO,以纳米ZnO为基体材料通过球磨法进行碳纳米管(CNTs)掺杂制备CNTs-ZnO复合材料，研究了改变CNTs含量(1%、3%、5%)对ZnO传感器气敏性能的影响。结果表明：通过CNTs掺杂，ZnO传感器的灵敏度得到大幅度提高且工作温度呈现降低的趋势，其中3%-CNTs/ZnO复合材料在最佳工作温度360℃下对乙醇浓度为100×10^-6的响应值(S=R_a/R_g)为98.329,是纯纳米ZnO的2.5倍。优异的性能主要归因于CNTs的掺杂增加了CNTs-ZnO复合材料的比表面积，而且可以促进CNTs在ZnO界面形成p-n异质结。     

碳纳米管/丁苯橡胶复合材料的电学性能

采用喷雾干燥法可制备不同配比的碳纳米管（Carbon nanotubes,CNTs）/粉末丁苯橡胶复合材料,观察CNTs在橡胶基体中的分散情况,检测复合材料的导电性能及介电性能,并进行了简要的理论分析。结果表明:CNTs在橡胶基体中获得了充分均匀的分散,有利于CNTs改性补强作用的发挥。与纯胶样品及填充炭黑（Carbon black,CB）样品相比, 填充CNTs样品在8~18GHz下具有较高的介电常数及低介电损耗。随着CNTs加入量的增加,CNTs/粉末丁苯橡胶复合材料的电导率逐渐升高,当CNTs加入量为60phr（per hundred rubber）时,与纯胶样品及添加60phr CB样品相比,电导率提高近10个数量级;复合材料内部导电同时存在隧道导电机制和渗逾导电机制。采用喷雾干燥法制备的CNTs/粉末丁苯橡胶复合材料,将是一种综合性能良好的新型纳米复合材料,有望在抗静电橡胶、电磁屏蔽及介电材料等领域获得应用。      

模拟冷却水中Al_2O_3纳米颗粒分散条件的优化

在模拟冷却水中添加Al_2O_3纳米颗粒制备纳米流体,用zeta电位表征纳米流体的稳定性。研究了十二烷基苯磺酸钠(SDBS)浓度、超声处理时间、溶液pH值对纳米流体稳定性的影响及最佳优化条件。单因素实验结果表明,随着SDBS浓度、超声处理时间、溶液pH值的增加,纳米颗粒zeta电位绝对值#ζ#均先增加后减小。在此基础上,运用响应曲面法中的BoxBehnken设计(BBD)模型对纳米颗粒分散条件进行优化,结果显示,SDBS浓度对zeta电位的贡献最大,其次为溶液p H值;SDBS浓度与pH值、超声时间与pH值两两之间的交互作用较明显;BBD模型给出模拟冷却水中纳米颗粒分散稳定性的优化条件为SDBS浓度0.339%(质量分数),超声时间61 min,pH值8.05,预测#ζ#为50.8 mV,实验测得优化条件下#ζ#为50.6 mV,与预测值接近。     

聚3,4-乙二氧噻吩包覆碳纳米管的原位化学氧化合成

报道了不同溶剂体系中原位化学氧化合成PEDOT/CNTs纳米复合物的实验,用红外光谱( IR)、拉曼光谱、透射电子显微镜(TEM) 以及四探针电导率仪对合成的纳米复合物进行了表征,可以看出:采用乙腈作为反应介质环境,可以获得反应充分完全的具有理想形态的聚乙二氧噻吩包覆碳纳米管的纳米复合纤维;通过对合成纳米复合纤维进行导电性方面的表征,证明通过一维纳米形态的碳纳米管和导电聚乙二氧噻吩的复合,可以获得具有更高导电性的纳米复合纤维.     

静电纺定向纳米纤维素-碳纳米管/聚乙烯醇复合纤维导电膜及性能

利用纤维素纳米晶须（CNCs）搭载碳纳米管（CNTs）在水相中形成均一稳定的纳米CNCs-CNTs导电复合物,并将其均匀分散于聚乙烯醇（PVA）基体中制得纺丝液,采用静电纺丝技术制备纤维定向排列的CNCs-CNTs/PVA复合导电膜。结果表明：CNCs-CNTs增强了纤维膜热力学性能,并赋予其导电功能;纤维的定向排列显著提高了膜的力学性能;随CNTs含量增加,纺丝液电导率和黏度提高,纤维直径减小;当CNCs和CNTs与PVA的质量比分别为8.0%和1.0%时,CNCs-CNTs/PVA的纤维直径、拉伸强度和电导率分别可达182 nm±35 nm、15.99 MPa±1.25 MPa和0.12 S/m±0.01 S/m;当电流密度为0.2 A/g时,其比电容可达127.1 F/g,且经过1 500次充放电循环后电容量仍保持在83.14%。基于导电膜优良的力学性能、热稳定性和导电性,CNCs-CNTs/PVA导电膜有望应用于可折叠超级电容器、柔性传感器和柔性电极材料等领域。     

石蜡填充碳纳米管纳米胶囊相变材料的制备及表征

以石蜡和经硝酸处理过的碳纳米管(CNTs)为原料,苯为溶剂,采用真空渗透法制备了纳米胶囊相变材料,并通过透射电镜、红外光谱、差示热量(DSC)等测试方法对样品进行了表征。结果表明:石蜡成功填充到CNTs管内,且在CNTs管外基本没有残留的石蜡。石蜡填充CNTs的过程中,两者之间仅是物理结合,没有发生化学反应。由于CNTs的纳米受限空间作用,纳米胶囊相变材料的相变温度比纯石蜡降低了5℃,根据DSC测试得到相变潜热值,计算得到填充在CNTs中石蜡的质量分数为16.24%。此研究对于纳米胶囊相变材料在太阳能储存、微电子设备冷却和节能技术中的应用具有非常重要的意义。     

具有负温度系数效应的导电硬质聚氨酯泡沫

采用高能球磨分散方法制备了稳定的聚合物多元醇/碳纳米管分散液,并通过原位聚合制备了导电聚氨酯（PU）/碳纳米管（CNTs）硬质泡沫复合材料。采用扫描电镜（SEM）表征了泡沫复合材料的结构,研究了CNTs含量对泡沫材料导电性的影响以及泡沫材料的负温度系数（NTC）效应,通过压缩测试考察了泡沫材料的力学性能。结果表明,CN...     

Effect of MWCNTs/ZnO inorganic fillers on the electrical,mechanical and thermal properties of SiR-based composites

Rubber insulation materials were widely used in the fields of electrical and electronic engineering, especially, which have excellent nonlinear electrical conductivity and can be employed to homogenize the electric field distribution of cable accessories. To enable the rubber materials, such as silicon rubber (SiR), to possess excellent nonlinear electrical conductivity has been a hot issue. In this paper, MWCNTs/ZnO inorganic fillers were prepared by mixing a small amount of multi-wall carbon nanotubes (MWCNTs) with zinc oxide (ZnO) nanosheets, and MWCNTs/ZnO/SiR composites were prepared. The macroscopical properties results show that the nonlinear electrical conductivity characteristics can be induced by filling appropriate content of MWCNTs/ZnO fillers, and the threshold field strength corresponding to the nonlinear conductivity gradually decreases with the increase of MWCNTs filling content, which further decreases with the increase of measured temperature. The COMSOL simulation results also verify that MWCNTs/ZnO/SiR composite with nonlinear conductivity can effectively reduce the electric field strength at the stress cone of cable accessories. In addition, the thermal conductivity and tensile strength for MWCNTs/ZnO/SiR composite are also improved comparing to pristine SiR. This work demonstrates MWCNTs/ZnO/SiR composites possess outstanding overall properties and have good potential to be used in the cable accessory.

     

纳米碳管与活性炭复合电极电吸附脱盐性能的研究

为考察纳米碳管（CNTs）、活性炭（AC）及其复合电极的电吸附脱盐性能，将其粉末压制成电极，组装成脱盐器，比较电极电吸附脱盐能力和脱盐能耗。结果表明，在活性炭电极中添加纳米碳管有效地降低了电极电阻和脱盐能耗，少量纳米碳管的添加能在一定程度上提高其电极比表面积、孔容以及在盐水中的比电容；当复合电极中纳米碳管的含量为10％时，其电极在盐水中的电吸附比电容达到113.5F/g，其电极脱盐效果最为显著，其脱盐耗能比活性炭电极降低约67％左右。     

Application of cryomilling to enhance material properties of carbon nanotube reinforced chitosan nanocomposites

Cryomilled multiwall carbon nanotube (MWCNT) reinforced chitosan nanocomposites having improved conductivity have been prepared by solution casting method. The MWCNTs were crushed to smaller particles via cryomilling, which was effective in cleaving the nanotubes regularly as well as in reducing the entanglements and agglomeration. The cryomilled CNTs were chemically oxidized by acid and base methods, where basic oxidation generated high graphitic structure. The cryomilled and oxidized CNTs were characterized by XRD, Raman spectroscopy, FTIR and SEM. The conductivity of the nanocomposites was improved by cryomilling and it was further improved by chemical oxidation. Base oxidized cryomilled CNT/chitosan nanocomposites showed large improvement in conductivity compared to all other nanocomposites having 1 wt.% CNT content. Thermal stability and tensile properties of the CNT/chitosan nanocomposites also have been improved significantly by the incorporation of acid and base oxidized cryomilled CNTs. SEM picture of the fractured surface and FTIR showed nano-level dispersion of the functionalized CNTs and good chemical interaction between chitosan and CNTs respectively.     

Electrochemical characteristics with the addition of carbon nanotubes and the manufacturing process for sulfur cathode in the Li/S cell

Carbon nanotubes (CNTs) were purified using acid solution, and CNT-sulfur composite powder was prepared via precipitation, using the purified CNTs. In addition, the effect of the purified CNTs (PUCNTs) on the electrochemical performance of the Li/S cell was investigated. After the purification, almost all the impurities in the as-synthesized CNTs (ASCNTs) were removed, and the dispersibility of the CNTs was improved. On the other hand, the concentration of the structural defects and of the disordered structures in the PUCNTs was increased due to the surface oxidation of the tubes during acid treatment. In the case of the PUCNT-S composite powder, the outer wall of the tubes was well covered with sulfur, as opposed to the tubes in the ASCNT-S composite powder. The Li/S cell containing ASCNT-S composite cathode showed a large voltage decrease and a 680 mAh/g capacity during the first discharge process. The Li/S cell with PUCNT-S composite cathode, however, showed a higher discharge capacity and better cycle performance than the cell with ASCNT-S composite cathode. The electrochemical performance of the Li/S cell was improved for the PUCNT-S composite cathode using the CNTs purified by acid treatment.     

石墨烯无溶剂纳米流体的制备及其在防腐导热涂料中的应用

通过在氧化石墨烯(GO)表面沉积Fe₃O₄纳米粒子制备得到GO@Fe₃O₄复合纳米粒子,再进一步通过表面接枝KH560-M2070,成功制备出石墨烯无溶剂纳米流体,从而改善石墨烯类材料在环氧树脂基体中的分散性和相容性。采用TEM、XRD分析方法对制备的石墨烯无溶剂纳米流体进行表征,同时对石墨烯流体/环氧树脂涂层的耐水、耐酸碱和导热性能进行了探究。     

Evidence for enhanced thermal conduction through percolating structures in nanofluids

The unusually large enhancement of thermal conductivity (k/k(f)～4.0, where k and k(f) are the thermal conductivities of the nanofluid and the base fluid, respectively) observed in a nanofluid containing linear chain-like aggregates provides direct evidence for efficient transport of heat through percolating paths. The nanofluid used was a stable colloidal suspension of magnetite (Fe(3)O(4)) nanoparticles of average diameter 6.7?nm, coated with oleic acid and dispersed in kerosene. The maximum enhancement under magnetic field was about 48φ (where φ is the volume fraction). The maximum enhancement is observed when chain-like aggregates are uniformly dispersed without clumping. These results also suggest that nanofluids containing well-dispersed nanoparticles (without aggregates) do not exhibit significant enhancement of thermal conductivity. Our findings offer promising applications for developing a new generation of nanofluids with tunable thermal conductivity.     

纳米G/Fe3O4复合材料的制备及其摩擦学性能

以石墨烯和纳米Fe3O4为原料,采用化学修饰的方法制备石墨烯负载四氧化三铁(G/Fe3O4)复合材料。通过透射电镜、X射线衍射仪、傅里叶红外光谱仪对复合材料进行表征;在SN5W-30润滑油中添加G/Fe3O4复合材料,利用等离子体光谱仪和四球摩擦试验机研究复合材料在润滑油中的分散稳定性和摩擦学性能。结果表明:使用油酸和硅烷偶联剂KH570共同修饰生成的G/Fe3O4复合材料在石墨烯表面分散效果比单独使用油酸修饰的好;沉淀稳定性实验表明:放置10d后,未添加复合材料的润滑油铁元素含量下降了48.3%,添加采用油酸修饰的复合材料铁元素含量下降了39%,添加采用油酸和KH570共同修饰的复合材料铁元素含量下降了31.1%;四球摩擦实验表明G/Fe3O4复合材料作为润滑油添加剂具有良好的摩擦学性能,使用油酸和KH570共同修饰的效果要比单独使用油酸修饰的好,最大无卡咬负荷PB增大了6.5%,摩斑直径减小了4.4%,摩擦因数降低了4.8%。     

高温型PVDF/PSSA复合膜的质子传导性能

通过自由基加聚反应制备了聚偏氟乙烯(PVDF)/聚苯乙烯磺酸(PSSA)复合膜,通过SEM、EDX、电化学阻抗谱(EIS)和TG等方法表征复合膜的微结构、电化学及尺寸稳定性和力学性能等性能与反应时间的关系.结果表明,随着反应时间的延长,PVDF/PSSA复合膜的含水率、质子传导率逐渐增大.反应时间为8 h的复合膜,其含水率在常温下达到4.4%,质子传导率达到0.375 S/cm,抗拉强度为32.1 MPa。这表明,在采用自由基加聚反应制备的复合膜中形成了稳固的半互穿网络(SIPN)结构,在保持一定的热稳定性能、尺寸稳定性以及力学性能的条件下,其质子传导性能明显改善.