原位聚合法制备聚丙烯酸修饰的ZnS量子点

采用原位聚合法对ZnS量子点表面进行聚丙烯酸(PAA)的修饰。利用XRD、FTIR、TEM、TGA、荧光测试等对ZnS@PAA复合纳米粒子进行系列表征。XRD分析表明,修饰后的ZnS仍为立方晶相。FTIR和TGA结果证明,ZnS纳米粒子表面存在PAA。TEM结果表明,修饰后ZnS@PAA复合纳米粒子在去离子水中分散良好,其直径有所增加,约为28 nm,且呈较明显的核-壳结构。荧光测试发现,修饰PAA前后ZnS@PAA复合纳米粒子的发光特性没有发生明显改变。实验表明,经PAA修饰后,ZnS@PAA复合纳米粒子在水溶液中的分散性和稳定性得到提高,抗氧化性和荧光稳定性也得到了一定的增强。      

粉末冶金法制备碳纳米管增强金属基复合材料研究进展

粉末冶金法具有工艺灵活,可设计性强等特点,是制备碳纳米管增强金属基复合材料的重要制备方法之一。简述了粉末冶金工艺制备金属基复合材料的流程和工艺特点,枚举若干实例总结了粉末冶金法制备碳纳米管增强金属基复合材料的性能特点,以及国内外研究现状,展望了该类材料未来发展前景。     

碳纳米管/SnO2复合材料制备及其超电容特性研究

以酸化处理的多壁碳纳米管及锡粉为原料,以硝酸水溶液为溶剂,在140℃回流的条件下成功制备了纳米氧化锡修饰碳纳米管的复合材料,通过改变反应时间及原料的比例来研究反应条件对包覆效果的影响,通过XRD,TEM对样品进行了表征,并用循环伏安曲线法对样品进行了电化学性能测试.结果表明,所得的复合材料具有一定的超电容特性.     

原位反应制备ZnS/还原氧化石墨烯复合材料及其光催化性能

以氧化石墨烯和ZnAc2为反应前驱物,采用二甲基亚砜(DMSO)作为硫源和反应溶剂,通过一步溶剂热法原位制备出负载ZnS的还原氧化石墨烯(RGO)复合材料(ZnS/RGO)。采用SEM、XRD、激光拉曼(Raman)和荧光光谱对样品的微观形貌和化学结构进行表征。结果显示:原位反应制备的ZnS/RGO复合材料是由呈圆球状并均匀负载的纳米ZnS和6~7层RGO层状结构组成;在模拟紫外光照射下,对甲基橙污染物的光催化结果表明,ZnS/RGO复合材料的降解效率明显高于纯ZnS;同时,在多次循环催化过程中,ZnS/RGO复合材料的光催化效率仍基本保持不变,表明原位反应使ZnS与RGO结合增强。荧光光谱结果表明,ZnS/RGO复合材料光催化效率增强的主要原因在于ZnS中光生电子通过RGO得到有效的分离,进而延长了电子-空穴的复合效率。     

Co2+掺杂水溶性ZnS量子点的制备及其光致发光性能

采用共沉淀法,以3-巯基丙酸为表面修饰剂,成功制备出Co2+掺杂水溶性ZnS量子点。采用X射线衍射仪、透射电子显微镜、原子发射光谱仪、紫外-可见吸收光谱仪和荧光分光光度计等,研究了Co2+掺杂剂及掺杂量对ZnS量子点的晶体结构、形貌和发光性能等的影响。结果表明:所得产物均为ZnS立方型闪锌矿结构,量子点呈不规则球形,粒径主要集中在5.2 nm左右;掺杂样品发红色荧光,发光性能明显增强,属于Co2+形成的杂质能级(4A1—4T1)与缺陷的复合发光。同时,利用红外吸收光谱对Co2+掺杂水溶性ZnS量子点的形成机理进行了初步探讨。     

碳纳米管／石英复合粉体的制备

采用表面活性剂和超声辅助的混酸处理工艺对碳纳米管进行了表面修饰，均获得了分散均匀的碳纳米管悬浮水溶液，利用傅立叶红外吸收光谱及Zeta电位等手段对其分散机理进行了分析；采用快速溶胶一凝胶法，制备了多种碳纳米管含量的石英基复合粉体，透射电镜观察显示两种修饰碳纳米管表面的方法都有效提高了碳纳米管在石英基体的分散性，制备出了均匀的碳纳米管／石英复合粉体。     

硫化锌纳米线的合成和表征

采用化学气相沉积法,以Zn(S2CNEt2)2为单源前驱体,Au为催化剂,在不同的温度下,得到了不同直径的六方相ZnS纳米线.在此基础上,改用Ni为催化剂,得到碳纳米管;改用单质S和Zn为原料,则得到立方相ZnS纳米线.在一定程度上实现了对ZnS纳米线的粒径和物相的控制合成,实现了利用催化剂对ZnS纳米线和碳纳米管的选择性合成.用X-射线粉末衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和能量分散光谱(EDS)对合成产物进行了表征.     

溶液共混法制备碳纳米管/双酚A型聚碳酸酯复合物的研究

用溶液共混法成功地制备了不同碳纳米管含量的双酚A型聚碳酸酯复合材料,用TEM,SEM和XPS对碳纳米管和所制备的复合材料进行了多种表征,结果表明碳纳米管的纯化效果较好,表面含有C-O,C=O和O-C=O等极性官能团,复合材料中聚碳酸酯对碳纳米管的包覆较好,聚碳酸酯的包覆量随碳纳米管含量的增加而降低,碳纳米管在聚合物基体中分散均匀,两相界面间存在较强的作用力。     

超支化聚酰胺修饰碳纳米管/环氧树脂复合材料的制备及性能

文中制备了不同支化度的超支化聚酰胺接枝碳纳米管,并对碳纳米管接枝前后的微观结构进行了表征。红外光谱和热重分析结果表明,超支化聚酰胺成功接枝到了碳纳米管表面;透射电子显微镜分析结果表明,3种支化度的超支化聚酰胺均在碳纳米管表面形成了聚合物包裹层,管径明显增加,且支化度越高,管径增加越多。进一步地,将上述所制备的超支化聚酰胺修饰碳纳米管加入环氧树脂体系,制备了不同改性环氧树脂复合材料,动态力学热分析和力学性能分析结果表明,超支化聚酰胺修饰碳纳米管/环氧树脂复合材料的储能模量、玻璃化转变温度和力学损耗峰高度均比未经修饰的碳纳米管/环氧树脂复合材料有所降低,冲击韧性明显提高,证明了超支化聚酰胺大量的分子支链对环氧树脂的增韧贡献,且支化度越高,增韧效果越明显;光学显微镜及扫描电子显微镜分析结果显示,超支化聚酰胺的加入明显改善了碳纳米管在环氧树脂中的分散性;从增韧机制来看,该体系的增韧机理属于碳纳米管拔出机制,碳纳米管的拔出物基本都是短凸棱拔出,碳纳米管大多被拉断,表明超支化聚酰胺修饰碳纳米管与环氧树脂形成了非常牢固的连接,对环氧树脂具有优异的增韧效果。     

CNTs@Y_2O_3:Eu~(3+)纳米复合材料的制备及其荧光温敏性能

采用表面活性剂(十二烷基苯磺酸钠)辅助的均相沉淀法,将稀土荧光前驱体氧化物复合在具有一维结构的碳纳米管表面,成功制备了具有一维结构的CNTs@Y_2O_3:Eu~(3+)纳米复合材料。通过SEM、XRD、TEM-EDS、FT-IR、TGA和PL等表征手段分别探究了复合材料的微观形貌结构、热稳定性、结晶度以及荧光性能。研究结果表明,CNTs@Y_2O_3:Eu~(3+)荧光复合材料在UV激发下显示出强烈的稀土Eu~(3+)特征荧光。同时,在400～1000℃不同煅烧温度范围内,该复合材料荧光强度随之发生明显变化,具有较强的温度敏感特性。     

Zigzag zinc blende ZnS nanowires: Large scale synthesis and their structure evolution induced by electron irradiation

Large scale zigzag zinc blende single crystal ZnS nanowires have been successfully synthesized during a vapor phase growth process together with a small yield of straight wurtzite single crystal ZnS nanowires. AuPd alloy nanoparticles were utilized to catalyze a vapor-solid-solid growth process of both types of ZnS nanowires, instead of the more common vapor-liquid-solid growth process. Surprisingly, the vapor-phase grown zigzag zinc blende ZnS nanowires are metastable under high-energy electron irradiation in a transmission electron microscope, with straight wurtzite nanowires being much more stable. Upon exposure to electron irradiation, a wurtzite ZnO nanoparticle layer formed on the zigzag zinc blende ZnS nanowire surface with concomitant displacement damage. Both electron inelastic scattering and surface oxidation as a result of electron-beam heating occur during this structure evolution process. When prolonged higher-voltage electron irradiation was applied, local zinc blende ZnS nanowire bodies evolved into ZnS-ZnO nanocables, and dispersed ZnS-ZnO nanoparticle networks. Random AuPd nanoparticles were observed distributed on zigzag ZnS nanowire surfaces, which might be responsible for a catalytic oxidation effect and speed up the surface oxidation-induced structure evolution.      

基于三元金属催化剂制备碳纳米管/三维石墨烯复合材料及电容性能

通过均匀沉淀法合成Ni-Mg-Al三元金属氧化物（TMO）,再通过一步化学气相沉积法（CVD）以CH₄为碳源、Ar为保护性气体,在原位还原的Ni上生长碳纳米管（CNTs）,在Mg和Al的金属氧化物上生长石墨烯（GR）,利用水热法刻蚀掉TMO,制备CNTs/三维石墨烯（3DGR）复合材料。基于CNTs与GR两种组分生长动力学的差异,通过控制Ni、Mg和Al三种金属离子的摩尔比、生长温度、生长时间,调控和优化CNTs/3DGR复合材料的结构及电容性能。借助TEM、SEM、EDS、Raman和XRD对CNTs/3DGR复合材料的结构、形貌、组分进行表征。结果表明,CNTs与GR协同作用为CNTs/3DGR复合材料提供了更多电子运输通道,可大幅提高导电性能,实现电容性能的提升,CNTs/3DGR复合材料的比电容最高可达20 F/g。      

The effect of sulfur on the structure of carbon nanotubes produced by a floating catalyst method

The effect of sulfur on the structures (shell number and diameter distribution) of carbon nanotubes (CNTs) was investigated in detail using high resolution transmission electronic microscopy (HRTEM) and Raman spectroscopy. Single-walled (SWNTs), double-walled (DWNTs), and multi-walled carbon nanotubes (MWNTs) with different diameter distributions were obtained only by increasing the sulfur addition amount with methane as carbon source. A similar structure change was found for ethanol as carbon source with changing the sulfur addition amount. These results indicate that addition of sulfur is necessary to enhance the growth of SWNTs and DWNTs, independent of the carbon source for our method. Based on the growth parameter study, HRTEM observations and kinetic considerations, the role of sulfur in the nucleation and growth of CNTs was discussed.     

碳纳米管/羟基磷灰石复合材料的制备及表征

以含钴介孔分子筛为催化剂、乙醇为碳源, 采用CVD法制备碳纳米管(CNTs)。通过原位合成法制备一系列不同碳纳米管含量的碳纳米管/羟基磷灰石(CNTs/HA)复合材料。分别采用XRD、FTIR、TEM、N₂吸附-脱附和Raman光谱等分析手段, 对所合成CNTs/HA复合材料的晶相、结构、形貌和比表面积等进行了表征。同时研究了碳纳米管的添加量对所合成CNTs/HA复合材料形貌的影响。XRD与Raman结果表明, 所得CNTs/HA复合粉体中仅有CNTs与HA两种物相, 纯度较高, 结晶度较好; TEM结果显示, CNTs/HA复合材料中CNTs表面均匀包裹着一层纳米级的针状HA晶粒, 两者形成了较强的界面结合, 且当CNTs与HA的质量比为3:17时, CNTs与HA形成最佳结合状态; N₂吸附-脱附表征结果表明, 与HA的比表面积相比, CNTs/HA复合材料具有较高比表面积。     

Controlling crystalline structure of ZnS nanocrystals only by tuning sulfur precursor addition rate

Unlike previous studies that emphasize the important role of thermodynamics or surface energy on the structure stabilization of ZnS nanocrystals, we successfully controlled the crystalline structure of ZnS nanocrystals simply by tuning sulfur precursor addition rate under exactly the same other conditions. We observed the structure of as prepared ZnS nanocrystals was evolved from wurtzite into zinc blende with increasing the addition rate of sulfur precursor. The method may extend to engineer other nanomaterials with desired physicochemical properties by controlling crystalline structure. On the other hand, it also makes a new approach to understand the crucial factors that determine the growth mechanism and the crystal structure of nanomaterials in theory.     

Nickel Oxide/Carbon Nanotubes Nanocomposite for Electrochemical Capacitance

A nanocomposite of nickel oxide/carbon nanotubes was prepared through a simple chemical precipitation followed by thermal annealing. The electrochemical capacitance of this electrode material was studied. When the mass fraction of CNTs (carbon nanotubes) in NiO/CNT composites increases, the electrical resistivity of nanocomposites decreases and becomes similar to that of pure CNTs when it reaches 30%. The specific surface area of composites increases with increasing CNT mass fraction and the specific capacitance reaches 160 F/g under 10 mA/g discharge current density at CNT mass fraction of 10%.     

Gaseous detonation fabrication of CNTs and CNTs doping with Fe based composites

The carbon nanotubes (CNTs) and CNTs doping with Fe based composites were rapid fabricated by gaseous detonation decomposition of oxygen, benzene and ferrocene mixed precursors. A series of novel experiments were designed to investigate the condensation and formation of carbon structural nanomaterials. The TEM, EDS, EDX, XRD and Raman characterizations provide fundamental evidence of the high yield and purity of the CNTs, CNTs doping with Fe composites during the gaseous detonation reaction process. The results showed that CNTs, CNTs with Fe based nanocrystals, spherical CCFNPs and their mixed products are with variant morphologies. The obtained CNTs is multi-walled carbon nanotubes and CNTs doping with a body-centered cubic iron or iron carbide cores, which can be obtained respectively through adjusting and controlling the detonation reaction environment and the precursors.     

工业级原料制备碳纳米管的研究

为降低碳纳米管批量制备的原料成本,以焦化苯和二茂铁为主要原料(工业级),采用浮游催化热解法制备碳纳米管,用TEM、SEM、Raman、XRD等对产物的形貌和结构进行观察和表征,着重讨论了二茂铁的分解温度和苯的挥发温度对碳纳米管的制备及其形貌的影响,并对其影响机理进行了分析.研究表明:在噻吩体积分数为0.55 mL/100 mL苯、炉膛反应温度为1170℃的前提下,当二茂铁的分解温度为150℃、苯的挥发温度为50℃时,用工业级原料完全可以制备出碳纳米管,此时,碳纳米管的内径分布在0.88~1.15 nm.     

Effect of a multiscale reinforcement by carbon fiber surface treatment with graphene oxide/carbon nanotubes on the mechanical properties of reinforced carbon/carbon composites

An effective carbon fiber/graphene oxide/carbon nanotubes (CF-GO-CNTs) multiscale reinforcement was prepared by co-grafting carbon nanotubes (CNTs) and graphene oxide (GO) onto the carbon fiber surface. The effects of surface modification on the properties of carbon fiber (CF) and the resulting composites was investigated systematically. The GO and CNTs were chemically grafted on the carbon fiber surface as a uniform coating, which could significantly increase the polar functional groups and surface energy of carbon fiber. In addition, the GO and CNTs co-grafted on the carbon fiber surface could improve interlaminar shear strength of the resulting composites by 48.12% and the interfacial shear strength of the resulting composites by 83.39%. The presence of GO and CNTs could significantly enhance both the area and wettability of fiber surface, leading to great increase in the mechanical properties of GO/CNTs/carbon fiber reinforced composites.     

多壁碳纳米管填充丁苯橡胶复合材料的研究

采用浓硝酸(HNO3)氧化处理后的多壁碳纳米管(MWNTs)与丁苯橡胶(SBR)及其他配合剂在开炼机上进行混炼加工制备MWNTs／橡胶复合材料，并与炭黑补强橡胶体系进行对比，进而研究了MWNTs／橡胶复合材料的物理性能，并初步探讨了该材料微观结构与性能之间的关系。结果表明：随着MWNTs质量百分含量的增加，橡胶复合材料的力学性能也随之增高；MWNTs／橡胶复合材料的抗撕裂强度(25．9kN／m)、硬度(58)、磨耗(0．22mL/1．61km)性能较炭黑／橡胶体系要好。由MWNTs补强的橡胶对开发具有低滚动滞后性和抗疲劳损失的轮胎胎面胶将有很大的实用潜力。