碳纳米管纳米复合材料的现状及问题的分析.doc

/碳纳米管纳米复合材料的现状及问题的分析摘 要文章介绍了碳纳米管的结构和性能，综述了碳纳米管/聚合物复合材料的制备方法及其聚合物结构复合材料和聚合物功能复合材料中的应用研究情况，在此基础上，分析了碳纳米管在复合材料制备过程中的纯化、分散、损伤和界面等问题，并展望了今后碳纳米管/聚合物复合材料的发展趋势。to picked this article introduces the structure and properties of carbon nanotubes, carbon nanotube/polymer composites are reviewed in this paper the preparation methods and the structure of polymer composite materials and the application of function of polymer composite materials research situation, on this basis, the analysis of the carbon nanotubes in preparation of composite materials in the process of purification, scattered, damage and interface problems, and prospects the future development trend of the carbon nanotubes/polymer composites.关键词碳纳米管；复合材料；结构；性能key words carbon nanotubes; Composite materials; Structure; performance自从 1991 年日本筑波 NEC 实验室的物理学家饭岛澄男(Sumio Iijima)1首次报道了碳纳米管以来，其独特的原子结构与性能引起了科学工作者的极大兴趣。按石墨层数的不同碳纳米管可以 分 为单壁碳 纳 米管(SWNTs) 和多壁碳 纳 米管(MWNTs)。碳纳米管具有极高的比表面积、力学性能(碳纳米管理论上的轴向弹性模量与抗张强度分别为 12 TPa 和 200Gpa)、卓越的热性能与电性能(碳纳米管在真空下的耐热温度可达 2800 ，导热率是金刚石的 2 倍，电子载流容量是铜导线的 1000 倍)2-7。碳纳米管的这些特性使其在复合材料领域成为理想的填料。聚合物容易加工并可制造成结构复杂的构件，采用传统的加工方法即可将聚合物/碳纳米管复合材料加工及制造成结构复杂的构件，并且在加工过程中不会破坏碳纳米管的结构，从而降低生产成本。因此，聚合物/碳纳米管复合材料被广泛地研究。Since 1991, tsukuba, Japan NEC LABS physicist mari says the clear male (Sumio Iijima) 1 reported for the first time since the carbon nanotube and its unique atomic structure and properties of generated much interest among the scientific workers. According to the graphite layers of different carbon nanotubes can be points of single-walled carbon nanotubes (SWNTs) and multi-walled carbon nanotubes (MWNTs). Carbon nanotubes have high specific surface area, mechanical properties, carbon nanotubes, in theory, the axial elastic modulus and tensile strength of 1 2 TPa and 200 gpa, respectively), excellent thermal properties and electric properties, carbon nanotubes heat temperature can reach 2800 under the condition of vacuum, thermal conductivity is 2 times that of the diamond, the electronic current carrying capacity is 1000 times that of copper wires) 2. These characteristics of carbon nanotubes make it an ideal filler in the field of composite materials. Polymer easy to processing and manufacturing into a complex structure, the traditional machining method of the polymer/carbon nanotube composite materials can be processed and made into a complex structure, and in the machining process will not destroy the structure of carbon nanotubes, thereby lowering the production cost. Therefore, polymer/carbon nanotube composite materials are widely studied.根据不同的应用目的，聚合物/碳纳米管复合材料可相应地分为结构复合材料和功能复合材料两大类。近几年，人们已经制备了各种各样的聚合物/碳纳米管复合材料，并对所制备的复合材料的力学性能、电性能、热性能、光性能等其它各种性能进行了广泛地研究，对这些研究结果分析表明：聚合物/碳纳米管复合材料的性能取决于多种因素，如碳纳米管的类型(单壁碳纳米管或多壁碳纳米管)，形态和结构(直径、长度和手性)等。文章主要对聚合物/碳纳米管复合材料的研究现状进行综述，并对其所面临的挑战进行讨论。According to the different application purpose, polymer/carbon nanotubes composites can be correspondingly divided into two categories: structural composites and functional composites. Preparation in recent years, people have all sorts of polymer/carbon nanotube composite material, and the preparation of the composite material mechanical properties, electrical properties, thermal properties, optical properties and other various performance were studied extensively, the analysis of these results show that the performance of polymer/carbon nanotubes composites depends on many factors, such as the type of carbon nanotubes (single-walled carbon nanotubes and multi-walled carbon nanotubes), morphology and structure (diameter, length, and chiral), etc. Article mainly discusses the research status of polymer/carbon nanotubes composites were summarized, and the challenges faced are discussed.1 聚合物/碳纳米管复合材料的制备1 the preparation of polymer/carbon nanotube composites聚合物/碳纳米管复合材料的制备方法主要有三种：液相共混、固相共融和原位聚合方法，其中以共混法较为普遍。Preparation methods of polymer/carbon nanotube composite materials mainly have three: blend in liquid phase and the solid phase in harmony through in situ polymerization method, with blending method is relatively common.1.1 溶液共混复合法1.1 solution blending complex legal溶液法是利用机械搅拌、磁力搅拌或高能超声将团聚的碳纳米管剥离开来，均匀分散在聚合物溶液中，再将多余的溶剂除去后即可获得聚合物/碳纳米管复合材料。这种方法的优点是操作简单、方便快捷，主要用来制备膜材料。Xu et al8和Lau et al.9采用这种方法制备了CNT/环氧树脂复合材料，并报道了复合材料的性能。除了环氧树脂，其它聚合物(如聚苯乙烯、聚乙烯醇和聚氯乙烯等)也可采用这种方法制备复合材料。Solution method is to use mechanical stirring, electromagnetic stirring or high-energy ultrasound to spin out the reunion of carbon nanotubes, and evenly dispersed in the polymer solution, then can obtain after solvent to remove excess of polymer/carbon nanotube composite materials. The advantage of this method is simple, fast and convenient, mainly used for the preparation of membrane materials. Xu et al and Lau et al. 8 9 in this way the CNT/epoxy resin composite material, and report the performance of composite materials. In addition to the epoxy resin, other polymer (such as polystyrene, polyvinyl alcohol and polyvinyl chloride (PVC), etc.) also can adopt this method of preparation of composite materials.1.2 熔融共混复合法1.2 legal melt blending熔融共混法是通过转子施加的剪切力将碳纳米管分散在聚合物熔体中。这种方法尤其适用于制备热塑性聚合物/碳纳米管复合材料。该方法的优点主要是可以避免溶剂或表面活性剂对复合材料的污染，复合物没有发现断裂和破损，但仅适用于耐高温、不易分解的聚合物中。Jin et al.10采用这种方法制备了 PMMA/ MWNT 复合材料，并研究其性能。结果表明碳纳米管均匀分散在聚合物基体中，没有明显的损坏。复合材料的储能模量显著提高。Melt blending method is through the rotor will shear forces applied by carbon nanotubes dispersed in the polymer melt. This method is especially suitable for preparation of thermoplastic polymer/carbon nanotube composite materials. Advantages of this method is mainly to avoid the pollution of solvents or surfactants to the composite material, compound found no fracture and broken, but will only apply to high temperature resistant, not easy decomposition of the polymer. Jin et al. 10 the PMMA/MWNT composites was prepared by this method, and study its performance. Results show that carbon nanotube homogeneously dispersed in polymer matrix, no obvious damage. Significantly higher storage modulus of the composite material.1.3 原位复合法1.3 in situ将碳纳米管分散在聚合物单体，加入引发剂，引发单体原位聚合生成高分子，得到聚合物/碳纳米管复合材料。这种方法被认为是提高碳纳米管分散及加强其与聚合物基体相互作用的最行之有效的方法。Jia et al.11采用原位聚合法制备了PMMA/SWNT 复合材料。结果表明碳纳米管与聚合物基体间存在强烈代写论文的黏结作用。这主要是因为 AIBN 在引发过程中打开碳纳米管的 键使之参与到 PMMA 的聚合反应中。采用经表面修饰的碳纳米管制备 PMMA/碳纳米管复合材料，不但可以提高碳纳米管在聚合物基体中的分散比例，复合材料的机械力学性能也可得到巨大的提高。Adding carbon nanotubes dispersed in polymer monomer, initiator, monomer in situ polymerization by generating high polymer, polymer/carbon nanotube composites. This method is considered to improve carbon nanotube dispersion and strengthen its interaction with the polymer substrate is the most effective method. Jia et al. 11 by in situ polymerization of PMMA/SWNT composites were prepared. Results show that carbon nanotubes and polymer matrix between strong write the essays for bonding. This is mainly because AIBN opens in the cause in the process of carbon nanotubes is a PI bond has involved in the polymerization of PMMA. Adopted by the surface modification of carbon nanotubes to prepare PMMA/carbon nanotube composite material, not only can increase the proportion of carbon nanotubes dispersed in polymer matrix and composite materials mechanical performance can get great improvement.2 聚合物/碳纳米管复合材料的研究现状2 the research status of polymer/carbon nanotube composites2.1 聚合物/碳纳米管结构复合材料2.1 polymer/carbon nanotube composite material structure碳纳米管因其超乎寻常的强度和刚度而被认为是制备新一代高性能结构复合材料的理想填料。近几年，科研人员针对聚合物/碳纳米管复合材料的机械力学性能展开了多方面的研究，其中，最令人印象深刻的是随着碳纳米管的加入，复合材料的弹性模量、抗张强度及断裂韧性的提高。Carbon nanotubes because of their extraordinary strength and stiffness is considered a preparation of a new generation of high performance composite materials structure of ideal filler. In recent years, the scientific research personnel for polymer/carbon nanotube composite materials mechanical performance of the various research, among them, the most impressive is that with the increase of carbon nanotubes, composite modulus of elasticity, tensile strength and fracture toughness increase.提高聚合物机械性能的主要问题是它们在聚合物基体内必须有良好的分散和分布，并增加它们与聚合物链的相互作用。通过优化加工条件和碳纳米管的表面化学性质，少许的添加量已经能够使性能获得显著的提升。预计在定向结构(如薄膜和纤维)中的效率最高，足以让其轴向性能发挥到极致。在连续纤维中的添加量，单壁碳纳米管已经达到 60 %以上，而且测定出的韧度相当突出。另外，只添加了少量多壁或单壁纳米管的工程纤维，其强度呈现出了较大的提升。普通纤维的直径仅有几微米，因此只能用纳米尺度的添加剂来对其进行增强。孙艳妮等12将碳纳米管羧化处理后再与高密度聚乙烯(HDPE)复合，采用熔融共混法制备了碳纳米管/高密度聚乙烯复合材料，并对其力学性能进行了研究。结果表明：碳纳米管的加入，提高了复合材料的屈服强度和拉伸模量，但同时却降低了材料的断裂强度和断裂伸长率。Liu 等13采用熔融混合法制得了 MWNT/PA6(尼龙 6)复合材料，结果表明，CNTs 在 PA6基体中得到了非常均匀的分散，且 CNTs 和聚合物基体间有非常强的界面粘接作用，加入 2 wt%(质量分数)的 MWNTs 时，PA6 的弹性模量和屈服强度分别提高了 214 %和 162 %。总之，碳纳米管对复合材料的机械性能的影响，在很大程度上取决于其质量分数、分散状况以及碳纳米管与基质之间的相互作用。其他因素，比如碳纳米管在复合材料中的取向，纤维在片层中的取向，以及官能团对碳纳米管表面改性的不均匀性，也可能有助于改善复合材料的最终机械性能。Improve the mechanical properties of polymers main problem is that they are within the polymer substrate must have good dispersion and distribution, and increase their interaction with the polymer chains. By optimizing the processing conditions and surface chemical properties of carbon nanotubes, a little amount performance have been able to get significant improvement. Is expected in the directional structure (such as films and fibers) of the highest efficiency, is enough to make the axial performance to the limit. In continuous fiber content, single-walled carbon nanotubes has reached more than 60%, and determine the toughness is quite outstanding. In addition, only added a small amount of multi-walled or single-walled nanotubes engineering fibers, the strength of revealed a large increase. Ordinary fiber diameter of only a few microns, therefore can only use the nanoscale additives to enhance it. Sun Yanni etc. 12 will be treated as carboxylation carbon nanotubes with high density polyethylene (HDPE) composite, again after the carbon nanotubes prepared by melt blending method/high density polyethylene composite material, and its mechanical properties were studied. Results show that carbon nanotubes joined, improve the yield strength and tensile modulus of composites, but at the same time, but lower the breaking strength and elongation at break of the material. Liu 13, such as the melting mix can MWNT/PA6 composite material (nylon 6), the results show that the CNTs in the PA6 matrix very evenly dispersed, and between CNTs and polymer matrix has very strong interface bonding effect, add 2 wt % (mass fraction) of MWNTs, the elastic modulus and yield strength of PA6 increased by 214% and 214% respectively. Overall, carbon nanotubes on the mechanical properties of composite materials, the influence of largely depends on its mass fraction, dispersion and the interaction between carbon nanotubes and the substrate. Other factors, such as carbon nanotubes composite materials in the orientation and fiber orientation in layers, and the functional groups of the nonuniformity of the surface modification of carbon nanotubes, could also contribute to the improvement of the final mechanical properties of composite materials.2.2 聚合物/碳纳米管功能复合材料2.2.1 导电复合材料聚合物/碳纳米管导电复合材料是静电喷涂、静电消除、磁盘制造及洁净空间等领域的理想材料。GE 公司14用碳纳米管制备导电复合材料，碳纳米管质量分数为 10 %的各种工程塑料如聚碳酸酯、聚酰胺和聚苯醚等的导电率均比用炭黑和金属纤维作填料时高，这种导电复合材料既有抗冲击的韧性，又方便操作，在汽车车体上得到广泛应用。LNP 公司成功制备了静电消散材料，即在 PEEK 和 PEI 中添加碳纳米管，用以生产晶片盒和磁盘驱动元件。它的离子污染比碳纤维材料要低65 %90 %。日本三菱化学公司也成功地用直接分散法生产出了含少量碳纳米管的 PC 复合材料，其表面极光洁，物理性能优异，是理想的抗静电材料15。另外，聚合物/碳纳米管导电复合材料的电阻可以随外力的变化而实现通-断动作，可用于压力传感器以及触摸控制开关16；利用该材料的电阻对各种化学气体的性质和浓度的敏感性，可制成各种气敏探测器，对各种气体及其混合物进行分类，或定量化检测和监控17；利用该材料的正温度效应，即当温度升至结晶聚合物熔点附近时，电阻迅速增大几个数量级，而当温度降回室温后，电阻值又回复至初始值，可应用于电路中自动调节输出功率，实现温度自控开关18。2.2.2 导热复合材料许多研究工作证明，碳纳米管是迄今为止人们所知的最好的导热材料。科学工作者预测，单壁碳纳米管在室温下的导热系数可高达 6600 W/mK19，而经分离后的多壁碳纳米管在室温下的导热系数是 30006600 W/mK。由此可以想象，碳纳米管可显著提高复合材料的导热系数及在高温下的热稳定性20。Wu 等21制 备 了 多 壁 碳 纳 米 管 / 高 密 度 聚 乙 烯(MWNTs/HDPE)复合材料，并对其热性能进行了深入的研究，实验结果表明：导热系数随着 MWNTs 含量的增加而升高。当MWNTs 的质量分数达到 38 h，混合材料的导热系数比纯HDPE 的高三倍多。徐化明等22采用原位聚合法制