碳纳米管增强铜铬基复合材料的制备及其性能研究

以带羧基官能团的碳纳米管和片状铜铬粉为原料,通过对片状铜铬粉表面进行亲水处理,并采用湿法分散—粉末冶金工艺制备得到了碳纳米管/铜铬复合材料,实现了碳纳米管在铜铬基体中的均匀分散.采用场发射扫描电镜观察了复合材料块体的组织形貌,并研究了碳纳米管和铬含量对复合材料力学性能和导电性能的影响.结果表明：碳纳米管的体积分数为2%,铬在合金粉中的质量分数为3%为最优体系;碳纳米管的加入使铜铬基体的屈服强度提高了约12%,抗拉强度提高了约13%,摩擦系数降低了约19%,导电率降低了约23%.     

碳纳米管增强铝基复合材料制备及性能研究

采用真空热压烧结法制备碳纳米管与 SiO2多相增强铝基复合材料,测量复合材料的体积密度,根据其理论密度计算其致密度;再对制得的复合材料进行硬度、抗压强度、抗剪强度等力学性能测试,并观察样品的剪切断口微观形貌,研究 CNTs 对复合材料力学性能的影响。低含量的碳纳米管由于其在铝基体中的分散性及弥散度较好,作为第二相增强相,所制备的铝基复合材料的致密度、硬度、抗压强度与剪切强度均优于高含量碳纳米管增强铝基复合材料。 CNTs 的含量、以及其在铝基体中的弥散度是影响铝基复合材料力学性能的关键因素。     

碳纳米管/高密度聚乙烯复合薄膜的结构与性能研究

以浮动催化化学气相沉积法生长的碳纳米管薄膜为主体,以高密度聚乙烯为修饰材料,采用溶液等温结晶工艺,制备内部为纳米混合杂化串晶结构的碳纳米管/高密度聚乙烯复合薄膜,并探究该结构产生的互锁效应对薄膜性能的影响机理.通过调节该结构的主要参数,即高密度聚乙烯片晶长度与周期距离,实现互锁效应的优化.研究结果表明,碳纳米管/高密度聚乙烯复合薄膜断裂应力为117.69 MPa,应变为52.85%,比原始碳纳米管薄膜提升了40%与270%.这种工艺方法为高性能纳米复合材料的制备提供了可能.     

煤矿井下灾区水凝胶密闭填充材料性能研究

针对目前矿井密闭填充材料在应用中的局限性,采用双溶液混合法制备了新型水凝胶密闭填充材料,研究了该材料胶凝时间影响因素、热稳定性与力学性能等.结果表明：胶凝温度每升高10℃,材料的胶凝时间大约减小1/2-1/3;且与引发剂浓度的-1/2次方成正比,与促凝剂含量呈一次线性关系.材料的失水率随加热时间增长呈线性增大,与加热温度的二次方成正比,与引发剂含量基本没有关系.另外,材料的变形率与单体添加量、交联剂浓度、促凝剂含量有关,弹性模量出现阶段性的变化,且分界点一般出现在纵向形变为50%的点处.     

氨等离子体改性对碳纳米管氧还原性能的影响

为了提高碳纳米管的氧还原性能,利用氨等离子体对碳纳米管进行了表面改性处理. 采用透射电子显微镜、拉曼光谱对改性前后碳纳米管的结构进行了表征,利用电化学方法比较分析了改性前后碳纳米管的氧还原性能. 研究发现,氨等离子体改性对碳纳米管的结构未产生明显的影响,改性后ID/IG值无变化,但改性后碳纳米管的氧还原起始电位为-146 mV、半峰电位高-243 mV、动力学电流为17.42 mA/cm2、电子转移数目为3.0,其均高于碳纳米管的相应参数. 等离子体表面改性工艺简单,改性后对氧还原性能显著提高.     

碳纳米管复合膜的制备及性能研究

针对膜过滤技术对印染废水中一些含苯环物质难以处理的问题,提出了利用碳纳米管制备新膜材料的方法。分别将碳纳米管(MWNT)和羧基化碳纳米管(c-MWNT)均匀分散在火棉胶溶液中,采用流涎法制备出碳纳米管复合膜;并用分光光度法对样液、滤液中的间苯二酚和茜素红的吸光度进行了对比测定,以考察膜的吸附性能。结果表明:制得的MWNT复合膜分别吸附了13.5%的间苯二酚和42.8%的茜素红;c-MWNT复合膜则分别吸附了33.2%的间苯二酚和80.3%的茜素红,复合膜对间苯二酚和茜素红表现出良好的吸附性,而且制得的复合膜极易再生,可重复使用。     

菊粉凝胶性能的研究

采用X-T2l型质构仪,研究了菊粉浓度、pH、金属离子、剪切速率对聚合度9-11的菊粉凝胶性能的影响。浓度超过40%、温度达到40℃,菊粉开始形成凝胶,随浓度和温度的提高,凝胶性能显著改变;Cu2+浓度0.20 mg/mL、pH5-7、剪切速度2 000 r/min,凝胶性能最佳。在几种金属离子中,铜离了促进凝胶形成的能力最强,但其离子浓度必需适中,否则过量的离子会对凝胶性能产生负面影响;加热和低酸性环境下菊粉易水解,对凝胶结构产生一定破坏作用。     

超声波振荡对碳纳米管形态的影响

采用TX-10表面活性剂作为分散剂,并用超声波振荡方法对碳纳米管（CNTs）进行了分散处理。利用透射电镜（TEM）观察了超声波振荡时间对碳纳米管分散状态的影响,并评价了碳纳米管的损伤。此外,通过静置悬浊液观察沉淀的方法,研究了该体系的稳定性。结果表明,CNTs的直径越小其抗弯截面系数也越小,在超声波侧向冲击的作用下产生的弯曲正应力越大,超声波振荡造成的损伤也越严重,最终导致较细纳米碳管在剪切的作用下长度急剧下降,这也是影响CNTs分散性及其悬浊液稳定性的重要原因。     

碳纳米管的电学性质

依据碳纳米管中电子-声子相互作用的原理,采用哈密顿量、量子化理论推导了二聚化对应能隙和相变温度,在紧束缚近似、量子理论和能带理论的基础上,利用周期性边界条件对碳纳米管Π电子进行了分析,讨论了碳纳米管的导电性,预测了室温下碳纳米管碳管中载流子输运方向.     

Structures and properties of PEDOT nanotubes prepared by a template synthesis method

PEDOT nanotubes were prepared by a template synthesis method. Based on our template, it was deduced that there are two successive processes in the formation of nanotubes. The first step is soakage of the porous templates by a polymer solution, and the second step is adsorption of free charged cationic groups and doped PEDOT onto the template surface with negative charges. XRD results showed that well orientated PEDOT chains were formed during the synthesis, moreover the arrange conductivity of molecular chains strongly affect the structures of PEDOT nanotubes. The nanotubes were measured to be about 5.5–17.6 S/cm, which is higher than that of nanotube pellet due to the high contact resistance between the adjacent nanotubes. Funded National Natural Science Foundation of China(No.: 60372002)     

多壁纳米碳管环的成环机理研究

利用连续介质模型和弹性能理论,分析了多壁纳米碳管环的形成过程.发现弯曲纳米碳管成形自由能为零的条件决定了多壁纳米碳管环的形成;并存在使直纳米碳管变弯的阈值条件,纳米碳管环是诸多弯曲构型中的一种稳定构型.此模型导出的多壁纳米碳管环半径与实测值符合.说明了连续介质弹性能理论在原子尺度下仍能使用及多壁纳米碳管环的形成是一个成形自由能为零的自组织过程.     

Impact on concrete mechanical properties of polypropylene fiber

在混凝土中加入不同掺量的聚丙烯纤维,形成聚丙烯纤维混凝土,通过立方体抗压强度试验、弯曲韧性试验、早期收缩抗裂试验,并与素混凝土试验结果进行对比,来确定不同掺量的聚丙烯纤维对于混凝土各个力学性能的影响,从而确定最佳的聚丙烯纤维掺量。     

Effect of Co-polyester antistatic agent modified by carbon nanotubes on the properties of polypropylene fibers

Antistatic polymer fibers were investigated by using carbon nanotubes (CNTs) to enhance the antistatic ability of inner antistatic agents based on the mechanism of attracting moisture by polar radical groups. It is indicated that the antistatic ability of the fibers filled with composite antistatic agents that contain CNTs and organic antistatic agents was superior to that of the fibers filled either with pure organic antistatic agents or pure CNTs. The antistatic ability of the composite antistatic agent fabricated by an in situ process was superior to that of the composite antistatic agent fabricated by direct dispersing CNTs in the antistatic agent carrier. Moreover, the heat-treated CNTs could further enhance the antistatic effect compared with the initial CNTs. The antistatic effect is significantly influenced by the content of CNTs in the composite antistatic agent.     

Development of supercapacitors based on carbon nanotubes

Block-type electrodes made of carbon nanotubes were fabricated by different processes. The volumetric specific capacitance based on such electrodes reached 107 F/cm3, which proves carbon nanotubes to be ideal candidate materials for supercapacitors. The composite electrodes consisting of carbon nanotubes and RuO2 ·xH2O were developed by the deposition of RuO2 on the surface of carbon nanotubes. Supercapacitors based on the composite electrodes show much higher specific capacitance than those based on pure carbon nanotube ones. A specific capacitance of 600 F/g can be achieved when the weight percent of RuO2· xH2O in the composite electrodes reaches 75% . In addition , supercapacitors based on the composite electrodes show both high energy density and high power density characteristics.     

Effects of size and surface modification of multi-walled carbon nanotubes on mechanical properties of polyurethane-based nanocomposites

Polyurethanes/multi-walled carbon nanotube (PU/CNT) composites were prepared with a help of ultrasonically dispersing CNT in the traditional procedure of synthesizing polyurethane. In this case, the various loading levels, sizes and surface-modified groups were considered to regulate the mechanical performances of the PU/CNT nanocomposites. Moreover, the structure and mechanical properties of all the PU/CNT nanocomposites were investigated by attenuated total reflection-Fourier transform infrared spectroscopy, dynamic mechanical analysis, scanning electron microscope, transmission electron microscope, and tensile testing. The experimental results showed that a moderate loading-level of 0.1wt% and a diameter of 10-15 nm for CNT could produce the maximum tensile strength and elongation while it was worth noting that the surface carboxylation of CNT could further enhance the tensile strength and elongation of the PU/CNT nanocomposites.     

碳纳米管增强钛基复合材料的界面应力分布

为了了解工业领域中综合性能优异的金属基复合材料,采用结构分析软件ANSYS建立了有限元模型,研究了复合材料界面应力场的分布情况.结果表明,在受压载荷作用下,钛基复合材料发生屈服现象的可能性较小,但碳纳米管的顶部界面边缘处出现了明显的应力集中现象,导致此处发生断裂破坏的可能性相对较大.在拉伸载荷作用下,钛基复合材料的应力分布比较均匀,且未出现明显的应力集中现象,因而复合材料发生屈服、断裂破坏的可能性较小.当碳纳米管的相位角为15°时,复合材料发生界面脱离和基体开裂的可能性相对较小.     

多壁纳米碳管的压力储氢研究

采用催化热解法制备了多壁纳米碳管，并对其进行酸化、灼烧、掺杂等一系列预处理后，在室温及氢气的压力分别为9，12MPa的条件下研究了多壁纳米碳管的储氢性能。通过对纳米碳管的不同处理可以提高纳米碳管储氢容量，掺杂金属锂后，纳米碳管的储氢量增加最大。     

纳米碳管葡萄糖生物传感器的研究

基于纳米碳管的特殊物理结构和电化学特性，利用多壁纳米碳管（MWCN）修饰酶电极葡萄糖生物传感器，分析传感器性能的改变并探索酶和电子中间体在纳米碳管表面的作用机制。在碳糊电极表面纳米碳管修饰能够加快铁氰化钾/亚铁氰化钾的氧化还原速度，提高响应电流水平，但没有发现纳米碳管有直接电子传递作用；同时纳米碳管提高了葡萄糖氧化酶（GOD）分子在反应过程中的相对活性。经纳米碳管修饰后，葡萄糖生物传感器表现出良好的线性和分辨率，检测灵敏度、检测范围、检测速度有所提高；尤其在人体血糖浓度范围内，响应电流幅度提高了50%，分辨率提高了两倍。