碳纳米管的表面功能化修饰机理及方法研究

碳纳米管作为一种一维纳米材料具有优异的性能,但是由于自身结构导致的不溶性,以及易于团聚和缺乏表面功能基团等实际问题,限制了其应用范围,因此,碳纳米管功能化修饰是碳纳米管应用研究的重点领域,本文介绍了碳纳米管表面功能化的几种主要方法:机械分散功能化、共价功能化、非公价功能化等,结合国内外研究进展,对碳纳米管功能化修饰的机理及方法进行综述。     

非共价键修饰碳纳米管及其在电化学中的应用进展

本文跟踪碳纳米管非共价键功能化修饰的研究进展,对功能化碳纳米管在传感器领域中的应用进行了综述。     

化学功能化修饰碳纳米管的表征方法探究

本文探讨了化学功能化修饰碳纳米管的表征方法,从形态形貌、光谱学、化学组成等方面对碳纳米管功能化的表征方法进行了综述。     

碳纳米管表面功能化修饰的研究进展

碳纳米管是一种新型碳结构的一维纳米材料,为典型的层状中空准圆管结构,密度小,六边形结构连接,具有优异的电学、力学、导热、光学等性能。但其表面缺少活性基团、分散性差、加工困难,限制了其应用。本文从有机修饰、机械修饰、无机包覆三方面介绍碳纳米管表面功能化修饰的方法,以及进行表面功能化修饰形成的碳纳米管复合材料性能改善的具体体现。     

碳纳米管功能化表面修饰研究进展

由于碳纳米管表面缺陷少、缺乏活性基团,并且具有很强的范德华力和很高的长径比,严重的影响了它的应用。本文从共价修饰和非共价修饰两方面,介绍了目前碳纳米管功能化修饰的方法和研究状况。从催化、医疗、材料等方面着重介绍了功能化修饰后的碳纳米管一些最新应用进展,并展望了碳纳米管的发展与应用前景。     

碳纳米管有机修饰和在生物、医学材料中的应用

这篇综述主要从碳纳米管的有机共价修饰和有机非共价修饰方面着手,重点阐述碳纳米管有机修饰的原理和方法,并且综合国内外的现状,研究了功能化的碳纳米管在生物、医学材料上的应用,展望了有机修饰的碳纳米管今后发展的热点方向。     

多壁碳纳米管接枝超支化聚(胺-酯)

采用混酸氧化,使碳纳米管表面产生羧基,再分别以接出法(grafting from)的方式在碳纳米管表面"长出"超支化大分子;以接入法(grafting to)的方式将由"一步法"合成的超支化聚(胺-酯)通过酯化反应接枝到碳纳米管表面。通过SEM、FTIR、TGA-DSC以及XRD等表征手段并结合酸碱滴定法测定修饰后碳纳米管表面的羟基密度,对功能化修饰的碳纳米管进行分析。结果表明,分别以"grafting from"和"grafting to"方式接枝超支化聚(胺-酯)后,碳纳米管的羟基密度分别为24.74 mmol/g和20.04 mmol/g,修饰后的碳纳米管分散性能明显提高,同时末端丰富的官能团为碳纳米管的进一步功能化修饰创造了条件。     

碳纳米管的功能化研究进展

碳纳米管是一种新型的炭材料，具有独特的结构，特殊的力学、电学、磁学及光学性能，已引起人们的广泛关注。本文介绍了近年来对碳纳米管功能化处理及其应用等方面的最新进展，讨论了碳纳米管的纯化、修饰、填充及功能化碳纳米管的应用，并对今后的研究方向作了展望。     

碳纳米管的功能化及其在复合材料中的应用分析

碳纳米管的结构独特,性能优异,而且具备可以低成本大规模的获得、良好的热稳定性以及可以调节的电子亲和力等特点,成为众多科学家关注的焦点,但是由于它不能够溶于水和有机溶剂,在实际应用方面也就受到了一定的制约,分析了碳纳米管的共价功能化、非共价功能化、和混杂功能化的修饰方法,并对其在金属基、聚合物基、陶瓷基等复合材料中的应用进行分析。     

羧基化碳纳米管的酯化与酰氯化修饰研究

采用稀硝酸和浓硝酸、浓硝酸和浓硫酸两种方法在碳纳米管上引入羧酸基团，利用羧酸基团修饰的碳纳米管分别与溴代正丁烷和氯化亚砜反应，在碳纳米管上引入了酯基和酰氯基团，采用红外光谱对所引入的基团进行了表征验证，为碳纳米管的进一步功能化和应用提供了实验方法。     

环氧树脂/碳纳米管复合材料制备及导电性能研究进展

简要介绍了环氧树脂/碳纳米管复合材料的组成以及碳纳米管在环氧树脂中的分散方法;综述了环氧树脂/碳纳米管复合材料的制备方法,包括溶液浇铸法、原位聚合法、化学改性法、混合固化剂辅助叠层法和树脂传递模塑法;总结了国内外对环氧树脂/碳纳米管复合材料导电性能的研究现状,并分析了影响其导电性能的因素,包括碳纳米管的比表面积、表面功能化和制备方法,剪切速率及固化条件等。     

Comparison of carbon nanotube modified electrodes for photovoltaic devices

Substrates with four different nanotube modifications have been prepared and their electron transport properties measured. Two modification techniques were compared; covalent chemical attachment of both single and multi-walled carbon nanotubes to transparent conductive (fluorine doped tin oxide) glass surfaces and chemical vapour deposition (CVD) growth of both single and multi-walled carbon nanotubes on highly doped conductive silicon wafers. These carbon nanotube modified substrates were investigated using scanning electron microscopy and substrates with nanotubes grown via CVD have a much higher density of nanotubes than substrates prepared using chemical attachment. Raman spectroscopy was used to verify that nanotube growth or attachment was successful. The covalent chemical attachment of nanotubes was found to increase substrate electron transfer substantially compared to that observed for the bare substrate. Nanotube growth also enhanced substrate conductivity but the effect is smaller than that observed for covalent attachment, despite a lower nanotube density in the attachment case. In both modification techniques, attachment and growth, single-walled carbon nanotubes were found to have superior electron transfer properties. Finally, solar cells were constructed from the nanotube modified substrates and the photoresponse from the different substrates was compared showing that chemically attached single-walled nanotubes led to the highest power generation.     

Decoration of multiwall nanotubes with cadmium sulfide nanoparticles

This study focuses on in situ synthesis of CdS nanoparticles on the surfaces of multiwalled carbon nanotubes. By chemical reaction of cadmium chloride and thioacetamide in the solution with carbon nanotubes, which were pretreated by air oxidization and acid modification, cadmium sulfide nanoparticles densely supported on carbon nanotubes with 10 nm size and homogeneous distribution were prepared. The composite material with the composite structure of CdS decorating the nanotube surfaces was characterized using scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction and electron diffraction pattern. The CdS nanoparticles are of cubic crystal structure, show good adhesion to the nanotubes. This method can be extended to prepare other inorganic nanoparticle-carbon nanotube composites.     

Effect of carbon nanotubes on the curing and thermomechanical behavior of epoxy/carbon nanotubes composites

The processing of carbon nanotube based nanocomposites is one of the fastest growing areas in materials research due to the potential of significantly changing material properties even at low carbon nanotube concentrations. The aim of our work is to study the curing and thermomechanical behavior of carbon nanotube/epoxy nanocomposites that are critical from an application standpoint. Multiwall carbon nanotubes–epoxy composites are prepared by solvent evaporation based on a commercially available epoxy system and functionalized multiwalled carbon nanotubes. Three weight ratio configurations are considered (0.1, 0.5, and 1.0 wt%) and compared to both the neat epoxy to investigate the nano‐enrichment effect. We focus here on the modification of the curing behavior of the epoxy polymer in the presence of carbon nanotubes. It has been observed that introducing the multiwall carbon nanotubes delays the polymerization process as revealed by the modification of the activation energy obtained by differential scanning calorimetry. The viscoelastic response of the nanocomposites was studied from the measurements of storage modulus and the loss factor using dynamic mechanical analysis to evaluate the effect of the interface in each matrix/carbon nanotube system with changing matrix mobility. These measurements provide indications about the increase in the storage modulus of the composites, shift in the glass transition temperature due to the restriction of polymer chain movement by carbon nanotubes. POLYM. COMPOS., 35:441–449, 2014. © 2013 Society of Plastics Engineers     

Structure modification of single-wall carbon nanotubes

Various purification processes were applied to single-wall carbon nanotubes synthesized by metal catalyzed laser ablation. Structure modifications introduced by these processes were investigated by high-resolution transmission electron microscopy and Raman spectroscopy. An apparent structure modification after purification was the increase of bundle size although breaking of nanotubes and a change of nanotube diameter distribution were also observed. More vigorous attacking of single-wall carbon nanotube structure was identified by a strong mixed-acid treatment.     

Microwave-assisted poly(glycidyl methacrylate)-functionalized multiwall carbon nanotubes with a ‘tendrillar’ nanofibrous polyaniline wrapping and their interaction at bio-interface

Multiwall carbon nanotubes (MWCNTs) were activated by microwave irradiation and covalently functionalized with poly(glycidyl methacrylate) (PGMA) through free radical polymerization using ‘fishing process’ when the propagating polymer radicals were attached onto the graphitic surface of the nanotube. The PGMA-functionalized MWCNTs were then used as a precursor to non-covalently wrap polyaniline (PAni) nanofiber onto them. The functionalized nanotubes exhibited stable dispersion up to 180 days in tetrahydrofuran, dimethyl formamide and dimethyl sulfoxide. Fourier transform infrared analyses indicated the attachment of the epoxide and benzenoid–quinoid functional moieties onto the nanotube surface. The PGMA coating on the nanotube and surrounding PAni nanofiber on the MWCNT scaffold were confirmed by transmission electron microscopy. The Raman spectroscopy confirmed the phonon-assisted modification of the nanotube. The differential action of the pristine and functionalized MWCNTs against an opportunistic bacterium (Escherichia coli ) and its plasmid deoxyribonucleic acid was also investigated. Pristine nanotubes exhibited bacterial inhibitory action and no condensation with the pET-32α(+) plasmid. On the other hand, the anti-bacterial PAni nanofiber and functionalized nanotubes showed complex formation with the bacterial plasmid.     

Effects of surface modification on rheological and mechanical properties of CNT/epoxy composites

Despite superior properties of carbon nanotubes (CNTs), physical properties of the CNT/epoxy composites are not improved significantly because interfacial bonding between the CNTs and the polymer matrix is weak. CNTs were treated by an acidic solution to remove impurities and modified subsequently by amine treatment or plasma oxidation to improve interfacial bonding and dispersion of nanotubes in the epoxy matrix. The functional groups on the surface of treated CNTs were investigated by X-ray photoelectron spectroscopy. The surface modified CNTs were embedded in the epoxy resin by ultra-sonication and the cured nanotube containing composites were characterized by field emission scanning electron microscopy. Rheological properties of nanotube containing epoxy resin and mechanical properties of the modified CNT/epoxy composites were improved because the modification of CNTs improved dispersion and interaction between the CNT and the epoxy resin.     

Preparation and characterization of alkylated carbon nanotube/polyimide nanocomposites

BACKGROUND: The development of carbon nanotube‐reinforced composites has been impeded by the difficult dispersion of the nanotubes in polymers and the weak interaction between the nanofiller and matrices. Efficient dispersion of carbon nanotubes is essential for the formation of a functional nanotube network in a composite matrix. RESULTS: Multiwalled carbon nanotubes (MWNTs) were incorporated into a polyimide matrix to produce MWNT/polyimide nanocomposites. To disperse well the MWNTs in the matrix and thus improve the interfacial adhesion between the nanotubes and the polymer, ‘branches’ were grafted onto the surface of the nanotubes by reacting octadecyl isocyanate with carboxylated MWNTs. The functionalized MWNTs were suspended in a precursor solution, and the dispersion was cast, followed by drying and imidization to obtain MWNT/polyimide nanocomposites. CONCLUSION: The functionalized MWNTs appear as a homogeneous dispersion in the polymer matrix. The thermal stability and the mechanical properties are greatly improved, which is attributed to the strong interactions between the functionalized MWNTs and the polyimide matrix. Copyright © 2009 Society of Chemical Industry     

碳纳米管/聚合物复合材料及其应用

碳纳米管具有优异的力学性能、热性能及电性能,因此在聚合物复合材料领域具有巨大的应用潜力。本文侧重介绍碳纳米管在聚合物中作为增强相、功能填料和智能元件方面的应用研究情况,讨论了碳纳米管聚合物复合材料界面、力学性能及应用研究存在的问题,展望了碳纳米管在航空航天复合材料领域的应用前景。     

Electrochemical behavior of multi-wall carbon nanotubes and electrocatalysis of toluene-filled nanotube film on gold electrode

The cyclic voltammetric behaviors of empty nanotubes and toluene-filled nanotubes were described. When the nanotube films exposed to air for one night, a pair of redox waves was observed that is probably ascribed to the presence of oxygen-containing groups bound to the surface of the nanotubes. Toluene-filled nanotube film is demonstrated to catalyze the electrochemical response of biomolecules such as dopamine and epinephrine, while empty multi-wall carbon nanotube film shows no or less electrocatalytic behavior to these biomolecules. This suggests that filled nanotubes have some particular properties compared to empty multi-wall carbon nanotubes and the development of filled nanotubes is necessary.