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。     

碳纳米管氧化功能化及其表征方法的研究进展

综述了碳纳米管氧化功能化的常用方法,评析了氧化条件对功能化效果的影响,介绍了碳纳米管结构表征的手段,指明了氧化功能化对碳纳米管实际应用的意义。     

碳纳米管的非共价功能化研究进展

综述了碳纳米管非共价功能化的一些新的研究进展情况,介绍了碳纳米管非共价功化的种类、方法和意义,并对功能化后的碳纳米管的性能表征方法及应用前景进行了介绍。针对碳纳米管非共价功能化后虽可同时保持原有的物化性质和引入的物化性质,但表征非常困难这一矛盾进行了评述,并对今后的发展进行了展望。     

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。     

功能化碳纳米管/聚合物复合分离膜

碳纳米管不仅具有优异的力学性质和超大的比表面积,同时具有优良的传输特性,将其添加到聚合物中制备复合分离膜,具有广阔的应用前景。通过化学改性将碳纳米管功能化,提高其在聚合物中的分散性,制备碳纳米管/聚合物复合膜。本文在介绍了碳纳米管功能化、碳纳米管/聚合物复合膜制备方法的基础上,综述了功能化碳纳米管的加入对复合分离膜亲水性、水通量、机械稳定性以及分离等性能的影响。总结了近年来对碳纳米管在聚合物膜内定向排列的研究进展及碳纳米管定向对复合膜相关性能的影响。由于碳纳米管材料的各向异性,利用电场、磁场及流场等对碳纳米管在聚合物膜内的分布进行定向,从而充分利用其优异的性能,是该类复合膜的研究方向。     

功能化碳纳米管材料在含重金属处理废水中的应用研究进展

结合近几年国内外研究情况阐述了碳纳米管的改性方法,系统介绍了碳纳米管及功能化碳纳米管的性能及特点,重点介绍了功能化碳纳米管在重金属废水处理中的应用研究进展,深入探索该类材料一些存在的问题与不足,提出了发展趋势和方向,并指导制备出高度选择和高效吸附多种重金属离子的改性碳纳米管材料。     

功能化改性多壁碳纳米管的制备方法研究

通过浓硝酸氧化法制备了功能化改性的多壁碳纳米管,同时研究了回流温度、回流时间及分离方式对多壁碳纳米管功能化效果的影响,并通过红外光谱仪、SEM和TEM方法对功能化改性后的多壁碳纳米管进行了表征。实验结果显示,用浓硝酸在80℃的温度下回流6h,过氧化氢浸泡24h后,离心分离制备得到的功能化改性后的多壁碳纳米管形貌最好。     

碳纳米管在电容去离子技术中的应用研究进展

主要总结了碳纳米管电极的成型方法,论述了以碳纳米管及碳纳米管复合材料为电极的电容去离子技术除盐性能影响因素,并总结了功能化碳纳米管、碳纳米管复合电极材料的研究成果。最后,展望了碳纳米管在电容去离子技术应用中的研究发展方向。     

功能化碳纳米管/环氧树脂多孔复合材料制备及电磁屏蔽性能

以马来酸酐（MA）为功能性单体,通过自由基反应制备了马来酸酐功能化的多壁碳纳米管（MA-MWCNT）;以MA-MWCNT、环氧树脂、蓖麻油酸改性的四乙烯五胺固化剂、釉粉、水为原料,通过悬浮乳液聚合法制备了功能化碳纳米管/环氧树脂多孔复合材料。采用拉曼光谱、X射线衍射、红外光谱、X射线光电子能谱对功能化的碳纳米管进行了表征和测试。采用扫描电镜（SEM）、表面电阻测量仪、矢量网络分析仪对复合材料的表面形貌、电导率和电磁屏蔽性能进行了测试。结果表明：马来酸酐功能化单体的引入能够很好地改善碳纳米管的分散性能及材料的电磁屏蔽性能;随着碳纳米管含量的增多,复合材料的电导率增大,电磁屏蔽效能峰值增大,材料的电磁屏蔽性能增强;加入功能化的碳纳米管比加入未功能化碳纳米管的电磁屏蔽性能高,多孔复合材料比无孔复合材料的电磁屏蔽性能高。当加入功能化的碳纳米管的量为3%时,制备得到的多孔材料电磁屏蔽性能最佳,其电磁屏蔽性能峰值达到31.1dB。     

离子液体在碳纳米管功能化及复合材料中的应用研究进展

离子液体具有低毒性、不易挥发、高的离子传导率、高的化学和热稳定性等特殊的性质,近几年在碳纳米管中的应用研究引起了广泛的关注.本文作者综述了离子液体近年来在碳纳米管的共价功能化、非共价功能化和聚合物复合材料中的应用研究进展,重点论述了其优势及展望.     

PET/碳纳米管共混物的研究进展

综述了聚对苯二甲酸乙二醇酯(PET)/碳纳米管(CNTs)的共混物的制备和性能。官能化CNTs比未官能化CNTs在PET母体中的分散性得到改善;PET/未官能化CNTs共混物和PET/官能化CNTs共混物相比PET,熔融结晶温度均增高,具有更高的结晶度;PET/未官能化CNTs共混物的熔点变化不大,而PET/官能化CNTs共混物的熔点的变化取决于官能化CNTs中引入官能团的化学结构;PET/未官能化CNTs共混物和PET/官能化CNTs共混物的熔体黏度均比PET有所提高,切力变稀行为比PET也有所增强;PET/未官能化CNTs共混物和PET/官能化CNTs共混物的热稳定性、导电性能及机械性能均得到改善。     

Preparation,structure and properties of thermoplastic olefin nanocomposites containing functionalized carbon nanotubes

The morphology and properties of multiwalled carbon nanotube modified polypropylene (PP)/ethylene–octene copolymer blends were studied. Polypropylene chains are covalently grafted onto the surface of carbon nanotubes (CNTs) in order to improve their interaction with the polymer matrix. It is observed that functionalization of CNTs improves their dispersion and increases the interfacial bonding between CNTs and polymer matrix. The functionalized CNTs are selectively distributed in the continuous polypropylene phase. The size of the dispersed elastomer phase decreases after the addition of CNTs. Functionalized CNTs act as a nucleating agent and increase the crystallinity of the polypropylene. More importantly, an important increase in impact strength, stiffness and toughness can be achieved through introducing functionalized CNTs. Copyright © 2011 Society of Chemical Industry     

Improvement of dispersion of carbon nanotubes in epoxy resin through pyrogallol functionalization

Multiwalled carbon nanotubes (MWNTs) were functionalized with pyrogallol. The functionalized MWNTs were well‐dispersed in the epoxy/curing agent/ethanol solution, as demonstrated by UV‐vis spectra and optical micrographs. Epoxy resin/MWNTs composites were prepared via solution mixing method. The cure behavior was characterized using differential scanning calorimetry. Pyrogallol‐functionalized carbon nanotubes (CNTs) reacted with the epoxy through the mediation reaction of pyrogallol with the curing agent, leading to the interfacial bonding between the functionalized carbon nanotubes (CNTs) and the resin matrix. Due to the excellent dispersion and interfacial bonding, the mechanical strength and electrical conductivity of the epoxy resin/CNTs composites have been improved. POLYM. ENG. SCI. 56:1079–1085, 2016. © 2016 Society of Plastics Engineers     

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.     

Comparative study of the thermal and mechanical properties of nanocomposites prepared by in situ polymerization of ε‐caprolactone and functionalized carbon nanotubes

As an effort to compare the influence of several types of functionalized carbon nanotubes (CNTs) upon the mechanical and thermal properties of nanocomposites prepared with a poly(ε‐caprolactone) (PCL) as matrix and functionalized CNTs as fillers; nanocomposites of PCL–CNTs were studied in this study. CNTs were synthesized by chemical vapor deposition using dry ethanol as the carbon source. High resolution scanning electron microscopy, high resolution transmission electron microscopy, and Raman and infrared spectroscopies were used to characterize the CNTs obtained. Four chemical synthesis routes were exploited to add different types of chemical groups onto the surface of purified CNTs. Specifically, the authors inserted: (i) N‐methylpyrrolidine, (ii) carboxyl and hydroxyl, (iii) urethane, and (iv) phenylmethanol groups onto CNTs surface. Nanocomposites were synthesized by in situ polymerization of ε‐caprolactone (ε‐CL) in presence of 1 wt% of each type of functionalized CNTs. Young's moduli of the nanocomposites prepared with N‐methylpyrrolidine or carboxyl and hydroxyl functionalized CNTs are higher than the one of pure PCL, whereas all the mechanical properties of the nanocomposites containing urethane or phenylmethanol groups evaluated at the break point were higher than those of pure PCL. Thermal stability of all the nanocomposites studied improved with respect to pure PCL. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers     

Development of plasticized PLA/NH2‐CNTs nanocomposite: potential of NH2‐CNTs to improve electroactive shape memory properties

A polymer nanocomposite system comprising epoxidized soya oil plasticized‐polylactic acid (PLA) and amine functionalized carbon nanotubes (NH₂ functionalized‐CNTs) has been prepared with the aim of producing electrically conductive PLA products suitable for shape memory (SM) applications. An influence of the addition of NH₂ functionalized‐CNTs on thermal, mechanical properties, and morphology development of plasticized PLA/NH₂ functionalized‐CNTs nanocomposite was investigated by differential scanning calorimetry, tensile tests, scanning electron microscope, and atomic force microscopy, respectively. In addition, electroactive SM behavior in resulting nanocomposite was evaluated by a bending test, and the recovery process was recorded with video camera. The results showed that SM behavior in nanocomposite was influenced by NH₂ functionalized‐CNTs weight percent in matrix. Nanocomposite with 5 wt% NH₂ functionalized‐CNTs showed optimum values of shape recovery due to its relatively high electrical conductivity, and an adequate degree of crosslinking between NH₂ functionalized‐CNTs and plasticized PLA matrix. However, more than 5 wt% loading of NH₂ functionalized‐CNTs dropped down an elongation at break, while tensile at break increased with the increasing of CNTs weight percent in matrix. Interesting point in this study is that all improvements in the properties of resulting PLA/NH₂ functionalized‐CNTs nanocomposite sheet were observed at very low filler content, while other literature reports where large quantities of CNTs were used. POLYM. COMPOS., 35:2129–2136, 2014. © 2014 Society of Plastics Engineers     

Preparation of liquid crystal 4'‐allyloxy‐biphenyl‐4‐ol functionalized MWCNTs and their application on improving mechanical and thermal properties of silicon resin

A liquid crystalline molecule, 4'‐allyloxy‐biphenyl‐4‐ol (AOBPO), was used to functionalize carbon nanotubers (CNTs) via physical means and chemical means, respectively. The physically functionalized CNTs (AOBPO‐CNTs) and chemically functionalized CNTs (AOBPO‐O‐CNTs) were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), fluorescent spectroscopy, and Raman spectroscopy. The two functionalized CNTs were mixed with silicone resin as fillers to fabricate organosilicone nanocomposites. Scanning electron microscopy (SEM) images indicated that the dispersion of CNTs in silicone resin and compatibility of CNTs with silicone resin were improved effectively after functionalization with liquid crystal via physical or chemical means. The thermal and mechanical properties testing indicated that, the chemically functionalized CNTs got a better effect in improvement of mechanical properties of silicon resin than the physically functionalized CNTs, whereas the physically functionalized CNTs was more applicable to enhance the thermal conductivity of silicon resin. The tensile strength of AOBPO‐O‐CNTs/silicon resin increased by 37.8% over that of neat CNTs/silicon resin when the mass fraction of AOBPO‐O‐CNTs was 1.0%, and the elastic modulus of AOBPO‐O‐CNTs/silicon resin increased by 32.8% over that of CNTs/silicon resin if it came up to 2.0%. The thermal conductivity of the resin filled with AOBPO‐CNTs was improved to be 1.176 W (m^?1 K^?1) at the mass fraction of 5.0%, which was enhanced more than 73.2% over that of CNTs/silicon resin. POLYM. ENG. SCI., 56:1118–1124, 2016. © 2016 Society of Plastics Engineers     

Behavior of load transfer in functionalized carbon nanotube/epoxy nanocomposites

This paper presents the correlation between the functional groups, interfacial microstructure and behavior of load transfer in carbon nanotube (CNT)/epoxy nanocomposites. Nanocomposites consisting of epoxy and CNTs with/without functionalities (amino and epoxide groups) are prepared and characterized to evaluate the CNT-matrix interactions based on strain-sensitive Raman spectroscopy. The results show that nanocomposites filled with functionalized CNTs exhibit a noticeable G′-band shift in tension while those containing pristine CNTs have a marginal shift, suggesting a more efficient load transfer between the epoxy matrix and functionalized CNTs. An interesting observation is that the slope of the G′-band shifts can be either positive or negative, depending on the functional groups on CNTs and the interfacial structures created between the functionalized CNTs and polymer matrix. The mechanisms behind this observation are discussed with reference to fractography and thermo-mechanical properties of nanocomposites.     

Effect of CNT decoration with silver nanoparticles on electrical conductivity of CNT-polymer composites

A simple approach to decorate carbon nanotube (CNT) with silver nanoparticles (Ag-NPs) was developed to enhance the electrical conductivity of CNT. CNTs were functionalized using ball milling in the presence of ammonium bicarbonate, followed by reduction of silver ions in N, N-dimethylformamide, producing silver decorated CNTs (Ag@CNTs). The Ag@CNTs were employed as conducting filler in epoxy resin to fabricate electrically conducting polymer composites. The electrical, thermal and mechanical properties of the composites were measured and compared with those containing pristine and functionalized CNTs. It was found that when pH was about six, highly dispersed Ag-NPs can be decorated on functionalized CNTs. The electrical conductivity of composites containing 0.10 wt% of Ag@CNTs was more than four orders of magnitude higher than those containing same content of pristine and functionalized CNTs, confirming the advantage of the Ag@CNTs as effective conducting filler. The ameliorating effect of improved electrical conductivity was not at the expense of thermal or mechanical properties.     

The synthesis of polyacrylonitrile/carbon nanotube microspheres by aqueous deposition polymerization under ultrasonication

Polyacrylonitrile (PAN)/carbon nanotube (CNT) microspheres with diameters approximately 300-500 nm were synthesized by aqueous deposition polymerization under ultrasonication. A new absorption band appeared in the Fourier transform infrared spectrum of the PAN/CNT microspheres indicated that the functionalized CNTs interacted chemically with the itaconic acid on the PAN macromolecules. The results from the UV-vis and Raman spectra suggested that the functionalized CNTs and PAN macromolecules had interfacial interaction. The peak shift for the radical breathing modes in Raman spectra indicated that the functionalized CNTs were debundled by the PAN macromolecules during polymerization under ultrasonication. X-ray diffraction data showed that the PAN/CNT microspheres had higher degree of crystallization and larger crystal size than those of PAN, which was confirmed by the second exothermic peak of the differential scanning calorimeter scan in a nitrogen atmosphere. Thermogravimetric analysis showed that the addition of the functionalized CNTs improved the thermal stability of PAN.