真空催化沉积法原位合成多壁和单壁碳纳米管

在真空下,在CVD法合成碳纳米管过程中,对有效利用金属催化剂薄膜合成分离单壁碳纳米管的方法进行了探讨。     

碳纳米管/聚合物复合材料研究和应用进展

碳纳米管的发现引起科学界及产业界的极大重视,大量的研究集中在碳纳米管的合成、生长机理、物理性能的表征等方面。随着碳纳米管合成、提纯、化学修饰等领域的研究不断取得进展,碳纳米管/聚合物复合材料的研究已成为世界科学研究的热点。综述了碳纳米管/聚合物复合材料研究在机械、电学、光学性能等方面所取得的进展与应用。     

碳纳米管在聚合物复合材料中的分散及应用

综述了碳纳米管在聚合物中的常用分散方法,并介绍了碳纳米管分散表征方法以及聚合物复合材料的合成工艺。加入碳纳米管可以不同程度地改善聚合物基体的性能,但对碳纳米管在聚合物中定向分散以及其结合机理研究甚少。最后介绍了聚合物/碳纳米管复合材料应用领域。随着碳纳米管的合成、化学修饰、分散工艺的不断改善,碳纳米管的应用将逐步向用量小、产生效益高的领域发展。     

二氧化钛/碳纳米管复合光催化剂的制备及性能研究

以钛酸丁酯和多壁碳纳米管为原料,采用溶胶-凝胶法原位合成了二氧化钛/碳纳米管复合光催化剂。以甲基橙为目标降解物,研究了紫外光照射下不同碳纳米管含量对二氧化钛光催化降解性能的影响。运用X射线衍射和紫外-可见漫反射谱研究了光催化剂的晶型结构和吸光性能。结果表明:适量的碳纳米管能够有效提高二氧化钛的光催化活性,但过多将导致其活性降低;原位添加的碳纳米管没有影响二氧化钛的晶型结构,但会抑制其晶粒的生长;引入碳纳米管后二氧化钛在吸收边带发生了明显红移,增强了对可见光的吸收能力。     

燃烧法合成碳纳米管

碳纳米管是一种新型的材料,其合成方法多种多样.本文主要介绍碳纳米管的燃烧合成法,包括层流扩散火焰法、逆流火焰法和预混火焰法,并对影响碳纳米管合成的因素以及燃烧合成法中碳纳米管的生长机理做了做了简要分析.     

非晶态氢氧化镍复合碳纳米管电极材料的电化学性能

采用快速冷冻化学共沉淀法制备非晶态Ni(OH)2粉体,将其作为电化学活性物质复合碳纳米管合成镍电极材料,研究了其电化学性能. 结果表明,加入碳纳米管有效减少了镍电极的电荷转移电阻,增大了电极反应过程的质子扩散系数. 复合0.5%(w)碳纳米管合成的非晶态氢氧化镍电极材料在1 C充放电制度下,放电终止电压为1.0 V时,其放电比容量高达336.5 mA×h/g,放电中值电压为1.251 V,充放电循环30次,放电比容量保持率为96.74%,表现出较好的高倍率充放电性能.     

碳纳米管的制备及其聚合物基复合材料的研究进展

本文综述了单壁碳纳米管的制备方法,重点阐述了化学气相沉积法的合成运用,并对目前碳纳米管在聚合物基纳米复合材料方面的研究做了综合阐述。     

国外动态

收率达30%的碳纳米管大量合成法日本电气公司1991年发现的碳纳米管(巴基管)是继石墨、金刚石、C_C_(60)之后的第4种碳形态。该公司最近研究成功大量合成碳纳米管的技术。在_(60)生成过程中发现的碳纳米管具有六边形碳铺     

化学气相沉积法合成碳纳米管研究进展

碳纳米管由于其独特的结构和优异的电学、光学、力学、热学等物理化学性能,在材料、电子器件、传感器、催化剂和能源等领域具有广泛的应用前景,但是如何低成本批量制备高品质的碳纳米管是实现碳纳米管大规模应用的关键。本文综述了近年来化学气相沉积法合成碳纳米管的研究进展,表明化学气相沉积法是大规模可控制备碳纳米管最有效的方法,并对其未来的发展方向进行了分析和展望。     

钴纳米颗粒催化酚醛树脂制备碳纳米管

以酚醛树脂为原料、硝酸钴为催化剂前驱体,利用催化酚醛树脂合成碳纳米管。研究了温度、催化剂含量等对催化合成碳纳米管的影响。结果表明:硝酸钴首先分解为Co3O4,而后被原位还原为Co纳米颗粒,Co纳米颗粒再催化酚醛树脂裂解释放出的含碳气体生成碳纳米管;碳纳米管起始生长温度为673 K,最适宜生长温度为1 273 K;碳纳米管生长遵循顶端生长模式;催化剂的最佳加入量为酚醛树脂质量的0.75%;所制备碳纳米管直径约为20~100 nm,长度可达10μm。     

碳纳米管在环氧树脂改性中的应用研究进展

阐述了碳纳米管(CNTs)在EP(环氧树脂)基复合材料中的应用情况,着重讨论了CNTs表面改性的原因及其对EP基复合材料性能(包括力学性能、热性能和电性能等)的影响,并介绍了国内外该类复合材料的研究成果。最后对CNTs/EP基复合材料的研究方向进行了展望。     

聚苯并双噁唑类聚合物的合成及改性

简述了聚对苯撑苯并双(?)唑(PBO)的合成方法,详述了直链烯烃型、稠环芳烃型、联苯取代基型、杂环型聚苯并双(?)唑类聚合物的合成方法。综述了等离子体处理法、偶联剂处理法、电晕处理法等一系列PBO纤维表面改性技术的研究进展,通过介绍PBO／碳纳米管复合材料和PBO／粘土复合材料的合成技术,简析了PBO的纳米改性的研究。指出聚苯并双(?)唑聚合物研究将集中在合成高相对分子质量的聚合物合成技术,通过纳米改性及表面改性提高其性能,扩大应用领域。     

Core‐shell structure of carbon nanotube nanocapsules reinforced poly(lactic acid) composites

In this study “core‐shell” structure of carbon nanotube (CNT) nanocapsules, which aimed at toughening poly(lactic acid) (PLA) were designed by a synthetic strategy consisting of two reaction steps. The first step was to produce reactive chemical bond to bridge CNTs and PLA. So coupling agent KH570 was used to modify CNTs (CNTs‐KH570). The second step involved ring open polymerization of lactide (LA). Lactide polymerized into PLA under catalysis and meanwhile grafted onto CNTs via KH570 (CNTs‐KH570‐PLA). Thus, the CNTs nanocapsules were constructed. Fourier transform infrared spectroscopy (FTIR) showed coupling agent KH570 succeeded in linking CNTs and PLA during LA polymerization. In addition, scanning electron microscopy (SEM) and transmission electron microscope (TEM) indicated CNTs dispersed homogeneous in PLA matrix and the compatibility between them was excellent. The mechanical test also suggested the designed nanocapsules had good effect on toughening PLA composites. This research found one economical and simple way to improve PLA mechanical properties and further broaden its application in many fields. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 44919.     

碳纳米管/NR复合材料的硫化特性

对机械混合制备的碳纳米管(CNTs)／NR复合材料硫化性能进行研究。结果表明，与炭黑补强胶料相比，加入CNTs后，NR胶料的焦烧时间略有延长，硫化返原现象减轻。应用几种不同工艺预处理的CNTs进行试验发现，除经混酸氧化处理CNTs对NR硫化产生明显迟滞效应外，其它几种CNTs填充胶料的硫化特性变化不大。应用CNTs填充橡胶材料，混炼胶中硫黄的用量应适当增大。     

Adsorption of Bisphenol A to a Carbon Nanotube Reduced Its Endocrine Disrupting Effect in Mice Male Offspring

Soluble carbon nanotubes (CNTs) have shown promise as materials for adsorption of environmental contaminants such as Bisphenol A (BPA), due to the high adsorption capacity and strong desorption hysteresis of BPA on CNTs. The adsorption of BPA to CNTs may change the properties of both BPA and CNTs, and induce different toxicity to human and living systems from that of BPA and CNTs alone. Herein, we report that oral exposure of BPA/MWCNT–COOH (carboxylated multi-walled carbon nantubes) adduct to mice during gestation and lactation period decreased the male offspring reproductive toxicity compared with those induced by BPA alone. The adduct decreased malondialdehyde (MDA) level in testis and follicle-stimulating hormone (FSH) in serum, but increased the level of serum testosterone in male offspring in comparison to BPA alone. Our investigations broadened the knowledge of nanotoxicity and provided important information on the safe application of CNTs.     

聚氨酯／碳纳米管复合材料的研究进展

近年来,利用碳纳米管制备聚氨酯复合材料引起人们的高度重视。本文对聚氨酯/碳纳米管复合材料的研究进展状况进行综述。概述了聚氨酯和碳纳米管的性质以及碳纳米管的改性处理方法;介绍了聚氨酯/碳纳米管复合材料的制备方法,包括物理共混法和原位聚合法;讨论了碳纳米管对复合材料力学性能、电学性能、光学性能以及其他性能的影响。结果表明,碳纳米管的加入使得复合材料在上述性能方面都有不同程度的改善。最后探讨了该研究领域存在的问题及今后可能的发展方向。     

Superior mechanical properties of lithium aluminosilicate composites by pyrolytic carbon intercalated carbon fibers/carbon nanotubes multi-scale reinforcements

Performance degradation always occurs in carbon fibers/carbon nanotubes (CFs/CNTs) multi-scale reinforced composites prepared by chemical vapor deposition (CVD) method. In this study, pyrolytic carbon (PyC) interlayers are introduced to overcome this problem, and the mechanism is studied in detail. The multi-scale reinforcements are combined with lithium aluminosilicate (LAS) glass-ceramic into ceramic matrix composites by slurry impregnation and hot pressing sintering. The results show that the PyC interlayers can protect the CFs from corrosion of the catalyst at high temperature, improve stress transfers and promote the synergy between various components. The CNTs and LAS matrix form a transition area, which causes deflection and shunting when cracks propagate. These factors have greatly increased the crack extension energy, so the mechanical properties have been greatly improved. The flexural strength, fracture toughness and work of fracture reach 602 ± 55 MPa, 10.7 ± 2 MPa m^1/2, 4.6 ± 0.7 kJ m⁻², respectively, which are 42.3%, 42.6% and 76.9% higher than CF/LAS. This work expands the study of the CFs/CNTs multi-scale reinforcements and the LAS composites, and provides a useful reference for the related research.     

Synthesis of nanosized SiC by low-temperature magnesiothermal reduction of nanocomposites of functionalized carbon nanotubes with MCM-48

Silicon carbide synthesis by a magnesiothermal method was investigated using MCM-48 as the silica source mechanically mixed with carbon nanotubes (CNTs) as the carbon source, and nanocomposites of MCM-48/functionalized CNTs (CNTF). SiC syntheses were carried out with different molar ratios of MCM-48, carbon and magnesium at 700?°C in argon. The MCM-48 and carbon nanotube starting materials and the SiC products were characterized by BET, XRD, FESEM, EDX and TEM. The effect of the carbon content and the type of CNTs (either functionalized or unfunctionalized) on the SiC synthesis was studied. The results show that an improved yield of SiC is obtained when the carbon nanotubes are functionalized, producing a better contact with the MCM-48. This improved contact between the reactants ensures a good degree of reaction in a stoichiometric mixture of silicon and carbon, with no improvement in product formation being achieved by the use of additional carbon. These findings suggest that the degree of contact between reactants is an important factor in the magnesiothermal synthesis of SiC. The SiC products from magnesiothermal synthesis of the functionalized nanocomposite precursors were shown by TEM and FESEM to have unusual nanofiber morphologies mimicking the morphology of the CNTF nanotubes.     

碳纳米管、碳化钨在直接法合成过氧化氢中的应用

选用新型纳米材料——碳纳米管（CNTs）作为催化剂载体,用沉积沉淀法制备负载型钯-铂合金催化剂。同时选用过渡金属碳化物材料（碳化钨）为催化剂,其具有类似于Pt的表面电子结构,有望替代贵金属催化剂。探讨了Pd-Pt/CNTs及碳化钨在氢氧直接合成过氧化氢反应中的催化性能。     

Mechanical behavior of advanced nano-laminates embedded with carbon nanotubes – a review

Embedding carbon nanotubes (CNTs) in load-bearing composite laminate hosts to turn them into nano-laminates is a rapidly emerging field and has tremendous potential in enhancing the mechanical performance of the host laminates. This state-of-the-art review intends to provide a physical insight into the understanding of the enhancing mechanisms of the processed and controlled CNTs in the nano-laminates. It focuses on four aspects: (1) physical characteristics of CNTs, including CNT length, diameter, weight percentage and surface functionalization; (2) processing and control techniques of CNTs in the fabrication of nano-laminates, including distribution, dispersion and orientation controls of CNTs; (3) mechanical properties along with their testing methods, including tension, in-plane compression, in-plane and interlaminar shear (ILS), flexure, mode I and mode II fracture toughness as well as compression-after-impact (CAI), ballistic protection and fatigue; and (4) CNT–matrix load transfer and enhancing mechanisms along with a few major governing factors. The selective and uniform production of CNTs with specific dimensions and physical properties has yet to be achieved on a consistent basis. Moreover, the processing details of CNTs vary very significantly among different researchers so that the processed CNTs share little common characteristics. There is little control over the CNT orientations in most fabrication processes of the nano-laminates except for some cases associated with chemical vapor deposition (CVD). There are only two reports on in-plane compression and there is only one on in-plane shear. For reinforcement-dominated mechanical properties such as longitudinal tension and flexure, there was little enhancement reported. However, the substantial enhancement in in-plane compression strength was also reported. For matrix-dominated mechanical properties, such as transverse tension, in-plane shear, ILS strength and mode I and mode II fracture toughness, a significant enhancement, albeit with substantially varying degrees, was reported for ILS strength and mode I and mode II fracture toughness values. Meanwhile, the lack of consistent characterization of those properties was also noticeable. There is little established understanding of the enhancing mechanisms in nano-laminates.