碳纳米管的功能化修饰及应用研究进展

碳纳米管以其独特的一维结构,优良的力学、电学、光学等性能,受到学术界的广泛关注。但是在实际应用中由于其纳米材料的强大范德华力,碳纳米管很容易聚集在一起。同时碳纳米管不溶于水及有机溶剂,所以限制了其在实际中的应用。因此要对碳纳米管进行表面改性,使其在溶剂中能良好地分散。主要介绍近年来碳纳米管的改性方法,以及在实际应用方面的研究。     

碳纳米管的绿色高效功能化修饰

碳纳米管的功能化修饰为其应用研究奠定了基础。介绍了基于高效、节能、环境友好化学反应的碳纳米管功能化的新方法和新进展，包括以水、离子试剂作为溶剂和不使用有机溶剂的绿色功能化方法，以及应用超声波、微波辐射等技术的快速功能化过程，并对今后的研究方向进行了展望。     

碳纳米管共价修饰功能化研究进展

综述了近年来国内外碳纳米管共价修饰功能化的研究进展,功能化后的碳纳米管不仅保持了原有的特异性质,而且还表现出修饰基团参加反应的活性,为碳纳米管的分散、组装及表面反应提供可能。     

表面功能化碳纳米管改性水性聚氨酯复合材料的制备与性能

以聚酯多元醇(PCDL)、异佛尔酮二异氰酸酯(IPDI)、二羟甲基丁酸(DMBA)、1,4-丁二醇(BDO)、双季戊四醇(DiPE)为原料,合成-NCO封端的水性聚氨酯预聚体(WPU);再以多巴胺(DOA)和γ-氨丙基三乙氧基硅烷(APTES)协同修饰碳纳米管(CNTs),得到A-DOA/CNTs,并与WPU进行共价连接、交联,制备了A-DOA/CNTs/WPU复合材料。通过红外光谱、X射线光电子能谱、透射电镜、扫描电镜、热重分析和拉伸性能等对材料结构和性能进行表征,探究了ADOA/CNTs的用量对胶膜耐水性、热性能、断面形貌及力学性能的影响。结果表明,当A-DOA/CNTs质量分数为0.75%时,能均匀分散在聚氨酯基体中,此时胶膜的综合性能最佳,水接触角为92.6°,吸水率5.7%,拉伸强度为29.6MPa,断裂伸长率为225%,质量损失T_10%时的热分解温度为267℃,与纯聚氨酯相比热分解温度提高了28℃,其耐热性、耐水性、力学性能均有显著提高。     

碳纳米管的表面修饰及其对碳纳米管/氟橡胶复合材料导电性能的影响

分别采用混酸和四氟化碳(CF4 ) 等离子体处理技术对碳纳米管(MWCNTs) 进行了表面修饰, 将处理前后的碳纳米管进行了XPS 和SEM 测试, 获得了处理后前的表面形貌和结构, 并采用溶液浇注的方式制备了MWCNTs/氟橡胶(FE) 复合材料, 探讨了不同碳纳米管状态(未处理、混酸处理、CF4等离子体处理) 的导电性能, 结果表明两种表面处理方式可以使MWCNTs 表面接上极性官能团。而且在相同的碳纳米管添加量下(质量分数分别为0. 1 %、0. 5 %、1. 0 %、2. 0 %) , 酸处理MWCNTs/ FE 的渗流阈值最小, 达0. 5 %。      

功能化碳纳米管的应用研究进展

碳纳米管具有独特的管状结构和优异的性能,由于其表面活性、分散能力的制约,影响了碳纳米管的应用。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。从光电通信、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,展望了碳纳米管的发展与应用前景。     

碳纳米管的功能化及其在复合材料中的应用

碳纳米管具有独特的结构和优异的性能,但其表面活性差、不溶于水和有机溶剂,极大地制约了碳纳米管的应用.介绍了碳纳米管共价功能化、非共价功能化、混杂功能化修饰方法,对比了各自的优缺点;综述了碳纳米管在聚合物基、金属基、陶瓷基复合材料中的作用机理和广泛应用,并对其进一步发展提出展望.高性能功能化修饰碳纳米管复合材料的开发和应用势必会越来越广.     

聚合物基复合材料制备中碳纳米管的分散方法

综述了碳纳米管／聚合物复合材料制备过程中碳纳米管预先分散所使用的方法。为实现碳纳米管在聚合物中的分散，首先要求加入的碳纳米管本身具备足够的分散度。碳纳米管的分散方法主要有：表面化学修饰、分散剂分散、超声分散、机械分散、溶剂分散。     

大豆分离蛋白对单壁碳纳米管的功能化修饰及其性能研究

采用生物表面活性剂大豆分离蛋白(SPI)功能化修饰经酸化提纯的单壁碳纳米管(O-SWCNTs),得到纳米复合材料(SPI-O-SWCNTs)。对SPI-O-SWCNTs及其性能进行了测试和表征。透射电子显微镜(TEM)观察表明:SPI有效提高了O-SWCNTs的分散性。X射线光电子能谱(XPS)和拉曼光谱分析表明:SPI通过物理作用吸附到了O-SWCNTs表面,导致O-SWCNTs表面的C原子混乱度少许增加以及电化学性能降低。药物体外释放实验和细胞毒性检验实验表明:SPI修饰后的O-SWCNTs,能够提高药物的缓释效果,并且降低了对细胞的毒性。     

异氰酸酯功能化碳纳米管/热塑性聚氨酯弹性体复合材料的制备及流变性能

采用甲苯-2,4-二异氰酸酯(TDI)对碳纳米管(CNT)进行表面修饰,制得TDI功能化CNT(CNT-TDI),将其分散于4,4′-二苯基甲烷二异氰酸酯中,通过原位聚合法制备CNT-TDI/热塑性聚氨酯弹性体(TPU)复合材料。利用FTIR、XPS和TG等测试手段,表征和分析了CNT-TDI的表面结构;利用旋转流变仪研究了CNT-TDI含量对CNT-TDI/TPU复合材料动态流变性能的影响。结果表明,TDI成功接枝改性CNT,接枝率约17%。动态流变研究结果表明,随CNT-TDI含量增加,复合材料的储能模量(G′)、损耗模量(G″)和复数黏度(η*)均明显提高,G′和G″交点对应的频率向低频移动,损耗峰频率也向低频偏移,说明复合材料的结构性增强,大分子链松弛时间延长;Han曲线上移且逐渐靠近对角线,van Gurp-Palmen曲线下移,说明复合材料的弹性响应逐渐增强;Cole-Cole曲线拖尾现象消失,说明填料的加入降低了TPU基体的微相分离程度。     

Photochemical modification of single-walled carbon nanotubes using HPHMP photoinitiator for enhanced organic solvent dispersion

Photochemical modification of single-walled carbon nanotubes (SWCNTs) was carried out by covalent attachment of 2-propanol-2-yl radicals on the surface of SWCNTs, which were engendered by the photolysis of 1-[4-(2-Hydroxyethoxy)-phenyl]-2-hydroxy-2-methyl-1-propane-1-one (HPHMP) under ultraviolet (UV) light. Pristine single-walled carbon nanotubes (p-SWCNTs) were dispersed in acetone along with HPHMP photoinitiator. After that, the mixture was irradiated by UV light to generate the free radicals which were introduced onto the surface of SWCNTs. The modification of SWCNTs was supported by UV/visible spectroscopy, Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, thermal gravimetric analysis–mass spectrometry (TGA–MS), and transmission electron microscopy (TEM). UV/visible results revealed the loss of van Hove singularities due to covalent modification. The modification was further verified by FT-IR showing the signals at 3421 and 1100 cm⁻¹ due to stretching and bending of O–H group, respectively. Moreover, other peaks at 2927 and 2858 cm⁻¹ indicated the asymmetric and symmetric stretching modes of aliphatic C–H bond, respectively. Raman spectra illustrated that the intensity ratio of the tangential mode to the disorder mode (I _G/I _D), for modified SWCNTs (F-SWCNTs), decreased nearly four times than p-SWCNTs. TGA–MS also evidenced the signal corresponding to m/z 59 at 400 °C indicating the presence of 2-propanol-2-yl groups. TEM and dispersibility data demonstrated that the sidewall modification detached the bundled structure, enhanced the dispersion in common organic solvents and retained the original size of SWCNTs without hefty modification, which could cut or damage the nanotubes.     

Efficient direct water dispersion of multi-walled carbon nanotubes by functionalization with lysine

A small molecule, lysine, has been attached onto the Multi-Walled carbon nanotubes (MWNTs) by producing acyl chloride on the carboxylic groups associated with the nanotubes. Subsequently, highly water-dispersed nanotubes were obtained. Stable concentration as high as 10 mg/ml was obtained in deionized water that was nearly 2 orders of magnitude higher than that obtained from the acidized MWNTs. The functionalized MWNTs can be dispersed in water under a wide range of pH values (5-14) and exhibit pH responsive. Combining the properties of carbon nanotubes and the versatility and biocompatibility of lysine, these lysine functionalized MWNTs could find potential applications in biological applications. And this method could also be used to functionalize other nanomaterials by lysine.     

多壁碳纳米管的表面改性及其在防火涂料中的应用

利用两亲性聚合物对多壁碳纳米管(MWCNTs)进行改性,采用红外光谱、热重分析手段对改性MWCNTs进行表征;将改性MWCNTs应用到膨胀型防火涂料体系中,研究了其对防火涂料性能的影响.结果表明:在适合的条件下两亲性聚合物可以被引入到多壁碳纳米管表面,改性后的MWCNTs在醋酸丁酯和水中具有良好的溶解性;合适含量的改性MWCNTs可以提高防火涂料受火后的炭化层强度和膨胀倍率,降低背温升高速率,增强涂层的抗开裂性能.     

Noncovalent functionalization of multi-walled carbon nanotubes with amphiphilic polymers containing pyrene pendants

A novel noncovalent approach was developed for the functionalization of multiwalled carbon nanotubes (MWNTs) using an amphiphilic copolymer of PVP-co-PAH containing pyrene pendants. A homogeneous polymer layer was formed on the surface of MWNTs, and the wrapped copolymer layer with a thickness of about 17.7 nm was found. The noncovalent modified MWNTs were dispersed very well in solvent of dimethylformamide (DMF), water and chloroform (CHCl₃), and the high stability of dispersed suspensions could be maintained for more than 2 months without observed MWNT precipitation. In addition, the dispersing behavior of the noncovalent functionalized MWNTs by PVP-co-PAH in a solvent mixture of water/CHCl₃ was also investigated, and it was found that a carbon nanotube layer was formed at the water/CHCl₃ interface.     

Functionalization of single-walled carbon nanotubes by citric acid/oxygen plasma treatment

A safe and simple method of functionalizing single-walled carbon nanotubes (SWCNTs) has been developed, that significantly increases their dispersibility in water. SWCNTs in pure ethanol are treated with a supersonic homogenizer and dried. Then they are wetted with weak citric acid solution. Finally an RF (13.56 MHz) citric acid/oxygen plasma reaction is carried out under optimum conditions. As a result, hydrophilic functional groups attach onto the SWCNT surfaces, which enhance their dispersibility in water. The attachment of functional groups is identified by the FT-IR spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis. The dispersibility and dispersion stability are studied by the precipitation tests, UV-visible spectroscopy, and transmission electron microscopy. These functionalized SWCNTs are expected to be used in various applications.     

Covalent Surface Chemistry of Single‐Walled Carbon Nanotubes

In this review article, we explore covalent chemical strategies for the functionalization of carbon‐nanotube surfaces. In recent years, nanotubes have been treated as chemical reagents (be it inorganic or organic) in their own right. Indeed, from their inherent structure, one can view nanotubes as sterically bulky, π‐conjugated ligands, or conversely as electron‐deficient alkenes. Hence, herein we seek to understand, from a structural perspective, the breadth and types of reactions single‐walled nanotubes (SWNTs) can undergo in solution phase, not only at the ends and defect sites but also along the sidewalls. Controllable chemical functionalization suggests that the unique electronic and mechanical properties of SWNTs can be tailored in a determinable manner. Moreover, prevailing themes in nanotube functionalization have been involved with dissolution of tubes.     

Flexible organic thin-film transistors using single-walled carbon nanotubes as an activated channel

We report on the fabrication of organic thin-film transistors (OTFTs) with a spun cross linked poly-4-vinylphenol (PVP) dielectric on a polyethersulphone (PES) flexible substrate. To improve the electrical performance of OTFTs, we employed a random single-walled carbon nanotubes (SWNTs) network as a carrier transfer underlay without sacrificing the flexibility of the TFTs. The random SWNTs showed that they can act as a semiconducting channel and conduction path to shorten the channel length in our TFTs. The flexible thin-film transistors (TFTs) with a random SWNTs/pentacene bilayer as an active channel exhibited an improved saturation field effect mobility (µ_sat) of 2.6 × 10^− 1 cm²/Vs compared to that of TFTs without the SWNTs underlay, while creating only a minor reduction of the current on/off ratio.     

碳纳米管溶解性及其化学修饰

详细评述了增加碳纳米管在水和有机溶剂中溶解性的途径，包括单一溶剂直接分散、电子供一受体电荷转移、可溶性聚合物或表面活性剂筒状胶束包裹等非共价键相互作用和顶端开口、化学衍生以及侧壁化学修饰等共价化学修饰。指出今后一段时期碳纳米管化学的主要任务为通过非共价的或共价的化学修饰，改善碳纳米管本身的性能和用途，并耦合其他如化学的、生物的或物理的功能扩展其应用范围。进一步深入理解碳纳米管化学(尤其是其溶液化学)反应理论。     

Functionalized single-walled carbon nanotubes for the improved solubilization and delivery of curcumin

The surface modification of single-walled carbon nanotubes (SWCNTs) can enhance their solubility and stability in water and biological systems. The present study demonstrated the application of the functionalized SWCNTs (f-SWCNTs) as drug-delivery vehicles. In this study, f-SWCNTs were functionalized with one of four different chemical groups for the delivery of curcumin to splenic lymphocytes. Since free curcumin can modulate the proliferation of splenic lymphocytes, we compared the abilities of different f-SWCNTs for the delivery of water-insoluble curcumin to inhibit cell proliferation, which were stimulated with concanavalin A (Con A) and lipopolysaccharide (LPS). The results showed that curcumin can be loaded onto the f-SWCNTs surface through π?π stacking with a loading capacity of 235–327 mg/g (curcumin/f-SWCNTs). The f-SWCNTs-curcumin complexes display considerable cell proliferation inhibition efficacy when compared with free curcumin diluted in dimethyl sulfoxide (DMSO). Furthermore, curcumin loaded onto SWCNTs functionalized with poly(ethylene glycol) (SW-PEG) showed good dispersion and stability in water, confirming the excellent biocompatibility of SW-PEG as a drug carrier.