碳纳米管悬浮液分散质量影响因素试验研究

选取常见的5种表面活性剂,开展碳纳米管悬浮液的分散性和稳定性实验,定量分析了超声时长、表面活性剂掺比和碳纳米管浓度对悬浮液分散性的影响,量化了使用表面活性剂的碳纳米管悬浮液稳定性。结果表明：(1)超声时长对碳纳米管悬浮液的分散性有显著影响,采用功率为270 W的超声处理,超声40min,悬浮液的分散性趋于平稳;(2)在平均最佳超声时长下,SDBS作表面活性剂具有最优的分散效果,吸光度峰值达到1.729;(3)随着碳纳米管浓度的增加,分散性呈波形变化,SDBS和Triton X-100作表面活性剂,均在碳纳米管浓度为6 g/L时,表现出最佳的分散效果;(4)SDBS作表面活性剂,短期内吸光度值下降较少,有良好的短期稳定性,Triton X-100作表面活性剂,短期内吸光度值下降较多,但7 d后下降较少,有较好的长期稳定性。     

阴非离子型Gemini表面活性剂驱油体系性能评价

为提高低渗透油藏采收率,开发了一种阴非离子型Gemini表面活性剂ANG7-Ⅳ-7,并测定体系的界面张力、乳化性能和吸附量。结果表明,ANG7-Ⅳ-7表面活性剂浓度在1⁴ g/L范围内,油水界面张力均可达到10-3m N/m的超低数量级,当ANG7-Ⅳ-7浓度为4 g/L时,能使油水界面张力达到最低值6.025×10-3m N/m;在注入浓度为4 g/L时,表面活性剂在油砂上的吸附量为2.035 mg/g。室内岩心驱油试验结果表明,4 g/L的ANG7-Ⅳ-7表面活性剂驱可在水驱后提高采收率11个百分点。     

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。     

阴非离子型Gemini表面活性剂驱油体系性能评价

为提高低渗透油藏采收率,开发了一种阴非离子型Gemini表面活性剂ANG7-Ⅳ-7,并测定体系的界面张力、乳化性能和吸附量。结果表明,ANG7-Ⅳ-7表面活性剂浓度在1~4 g/L范围内,油水界面张力均可达到10-3m N/m的超低数量级,当ANG7-Ⅳ-7浓度为4 g/L时,能使油水界面张力达到最低值6.025×10-3m N/m;在注入浓度为4 g/L时,表面活性剂在油砂上的吸附量为2.035 mg/g。室内岩心驱油试验结果表明,4 g/L的ANG7-Ⅳ-7表面活性剂驱可在水驱后提高采收率11个百分点。     

表面活性剂分散碳纳米管的进展

碳纳米管容易聚集成束或缠绕,严重制约了碳纳米管的应用。通过表面功能化可增强碳纳米管在溶剂中的溶解性和其他基质材料中的分散性,从而提高碳纳米管的实际使用价值。用表面活性剂分散碳纳米管的方法进行综述,总结了各种表面活性剂的优缺点并提出了表面活性剂在碳纳米管应用的展望。     

表面活性剂对去血渍复合酶中蛋白酶活性的影响

研究了3种类型8种常用表面活性剂LAS,K12,AES,AOS,TX-10,6501,CAB以及AEO9对去血渍复合酶中蛋白酶活性的影响,表面活性剂浓度设定为0.2~0.8 g/L。结果表明:阴离子表面活性剂LAS,K12,AES和AOS在一般洗涤浓度0.2~0.5 g/L下对蛋白酶活性无明显影响,但在0.8 g/L的高浓度时表现出一定的抑制作用,其中LAS的抑制作用最大;非离子表面活性剂TX-10,6501和AEO9以及两性离子表面活性剂CAB在0.2~0.5 g/L浓度下的激活作用比较明显,这种激活作用随着浓度的继续增大至0.8 g/L而逐渐减弱。总体来说,阴离子表面活性剂在0.2~0.5 g/L浓度下能与去血渍复合酶中蛋白酶良好配伍,而非离子表面活性剂和两性离子表面活性剂在整个实验浓度下都能与去血渍复合酶中蛋白酶良好配伍。     

超声辅助芬顿氧化法制备功能化碳纳米管的研究

以FeSO_4·7H_2O及H_2O_2为原料配制芬顿试剂,对多壁碳纳米管(CVD法制备)进行处理,在超声辅助下制备芬顿功能化碳纳米管,对功能化前后碳纳米管的宏观液相体系稳定性、微观形貌、表面官能团情况及热失重等性能进行测试与表征。结果表明:经过芬顿功能化处理后的碳纳米管表面接枝了羧基、羟基等极性基团,处理后的碳纳米管曲率减小,团聚、缠结度降低,能均匀的混合于有机溶剂且溶液体系稳定。     

碳纳米管改性填料对氟碳涂料性能的影响

采用混合酸和表面活性剂对碳纳米管表面进行改性处理,利用改性碳纳米管与不同的填料构造复合填料,并与FEVE氟碳树脂合成了碳纳米管改性复合氟碳材料,并将其涂覆在陶瓷基底上形成氟碳涂层。采用红外光谱（FTIR）对表面改性后的碳纳米管进行了表征分析,用扫描电镜（SEM）、接触角测量仪等仪器观察和测试了纳米复合氟碳涂层表面的微观结构及疏水性。研究结果表明：用混合酸和表面活性剂改性碳纳米管,碳纳米管的缠绕、团聚现象得到明显的改善,提高了其在氟碳树脂体系中的分散性能;当改性碳纳米管的量为0.75 g时,涂层的憎水性能较好。     

表面活性剂对复合刷镀液中纳米WC分散性的影响

研究了在(Ni-P)-纳米WC复合刷镀液中添加阴离子型表面活性剂SDS、阳离子型表面活性剂PEI、非离子型表面活性剂OP对分散体系分散效果的影响.结果表明:表面活性剂能有效阻止复合刷镀液中微粒的絮凝、团聚,其用量对复合刷镀液分散效果有显著的影响.当阴离子型表面活性剂SDS的质量浓度为0.2g/L,阳离子型表面活性剂PEI为O.8g/L时,刷镀液中沉降粉体体积最小,添加非离子型表面活性剂OP的分散体系分散效果较差.     

新型羟基磺基甜菜碱/聚丙烯酰胺二元复合体系性能评价

新型羟基磺基甜菜碱表面活性剂与相对分子质量为2 500万的聚丙烯酰胺进行复合,测定体系的界面张力、黏弹性及乳化性能。结果表明,新型羟基磺基甜菜碱表面活性剂在浓度2.16 mmol/L时,表面张力33.39 m N/m,且乳化性能较好,具有较好的表面活性剂性能。相比于单独的表面活性剂,二元复合体系使溶液的临界胶束浓度增大,且界面张力也升高。当表面活性剂浓度为1.3 g/L,聚合物浓度为0.5 g/L时,体系的界面张力达到最低。聚合物的加入能显著降低体系的粘弹性,且随着聚合物浓度的增加,出现黏度最大值的表面活性剂的浓度越低。当表面活性剂水溶液质量浓度1.3 g/L,聚合物浓度1.5 g/L时,体系乳化性能最佳,实验表明,在低渗透岩心中,可以提高采收率5.78%。     

Dispersion, interfacial interaction and re-agglomeration of functionalized carbon nanotubes in epoxy composites

The surface, interfacial and dispersion properties of carbon nanotubes (CNTs), and the mechanical properties of the CNT/epoxy composites affected by CNT functionalization are investigated. It is demonstrated that there exists strong correlations between amino-functionalization, dispersion, wettability, interfacial interaction and re-agglomeration behaviour of CNTs and the corresponding mechanical and thermo-mechanical properties of CNT/epoxy composites. The amino-functionalized CNTs exhibit higher surface energy and much better wettability with epoxy resin than the pristine CNTs, and the attached amine molecules arising from the functionalization effectively inhibit the re-agglomeration of CNTs during the curing of resin. These ameliorating effects along with improved interfacial adhesion between the matrix and functionalized CNTs through covalent bonds result in improved flexural and thermo-mechanical properties compared with those without functionalization.     

碳纳米管在聚合物基体中的分散方法

综述了碳纳米管（CNTs）在聚合物基体中的分散方法，包括直接分散法和表面修饰法，其中表面修饰又根据是否形成共价键分为两类，重点叙述了近几年成为研究热点的非共价键修饰法。直接分散法简单、快捷，保证了CNTs的结构完整性，但分散效果较差；表面修饰法通过共价键或非共价键的方式对CNTs的表面进行改性，克服了直接分散法的缺点，但共价键的形成会破坏CNTs的结构完整性，造成CNTs其他性能的下降，而非共价键修饰又存在结合不牢固的问题。因此，CNTs在聚合物基体中的分散方法仍是今后聚合物／CNTs复合材料应用中需要解决的一个重点问题。     

Effect of SWCNT dispersion on epoxy nanocomposite properties

In nanocomposites containing single wall carbon nanotubes (SWCNTs), the final properties strongly depend on the dispersion quality of these fillers. Various methods have been used to improve the dispersion of nanofillers; however, one of the most effective ways is to functionalize carbon nanotubes (CNTs) with covalent and noncovalent functional groups. In this work, the dispersion of SWCNTs in an epoxy system was studied by using surfactants, acid (COOH), and ester groups (PGE)‐modified CNTs. Rheological and scanning electron microscopy analysis showed that functionalization of CNTs helped in improving the dispersion of fillers in the epoxy matrix. Systems with surfactant modified SWCNTs (1 wt%) exhibited the highest storage modulus at low frequencies after 5‐min sonication. This behavior is associated to a stronger network of fillers as a result of a good dispersion. However, longer sonication times lowered the storage modulus, corresponding to a degradation of the tubes. The effect of the dispersion quality on mechanical properties was also studied using a three‐point bending set‐up. POLYM. COMPOS.,, 2012. © 2012 Society of Plastics Engineers     

DNA-Functionalized Carbon Nanotubes: Synthesis,Self-Assembly,and Applications

Carbon nanotubes (CNTs) possess outstanding structural, mechanical, and electronic properties. Nevertheless, to achieve the full potential of CNTs, researchers must develop new purification methodologies or improvements in the existing purification and separation protocols, design and study novel functionalization chemistries that result in increased solubility of the CNTs without altering their properties, and devise a straightforward methodology for the attachment of aligned CNTs on solid substrates. To address these challenges, our group has studied the chemical functionalization of CNTs with deoxyribonucleic acid (DNA)—by covalent and non-covalent approaches—in combination with the self-assembling technique. In this short review, we will present an overview of DNA-functionalized CNTs, focusing on the main findings of our group, and the application of the DNA-CNT complexes as electrochemical biosensors.     

改性碳纳米管增强环氧树脂力学性能研究进展

具有低密度、高强度和高模量等优异力学性能的碳纳米管(CNTs)是环氧树脂(EP)基体的理想增强材料,然而CNTs在EP基体中分散性较差,并且其与EP之间难以形成有效的结合界面,这成为制约CNTs/EP复合材料力学性能进一步增强的关键因素,对CNTs进行官能化改性则是解决上述问题的有效途径之一。从增强EP力学性能方面介绍了CNTs的羧基化、胺基化和硅烷化等官能团化改性方法的研究应用进展,总结了其改性机理,结合该领域研究中的一些不足以及实际应用的需求,指出了进一步的研究方向。     

Adsorption of binary CO2/CH4 mixtures using carbon nanotubes: Effects of confinement and surface functionalization

Effect of confinement and surface functionalization in carbon nanotubes (CNTs) on the competitive adsorption of a binary CO₂/CH₄ mixture has been investigated by grand canonical Monte Carlo simulations. Adsorption using CNTs with different functionalization arrangements, different diameters, different functionalization degrees, and different functional groups, such as –COOH, –CO, –OH, –CH₃, is investigated. Effects of (a) the pore textural properties, such as pore size and accessible surface area, and (b) the gas–adsorbent interaction, especially the electrostatic interaction, are discussed. From these results, we discuss the impact that variables such as confinement and surface functionalization have on the performance for CO₂ separation.     

The effect of surface functionalization of carbon nanotubes on properties of natural rubber/carbon nanotube composites

The objective of this study was to prepare natural rubber composites filled with carbon nanotubes (CNTs) that show an electrical percolation threshold at very low CNT concentrations. Therefore, two methods of surface functionalization of CNTs were investigated to enable an improved dispersion of CNTs and chemical interaction between CNTs and rubber matrix. On one hand, the CNTs have been functionalized ex situ by acid treatment and silanization reaction with bis(triethoxysilylpropyl) tetrasulfide before mixing with the rubber and otherwise in situ functionalization was directly carried out during the processing of the composites in the internal mixer. The grafting of silane molecules onto CNT surface was established by Fourier transform infrared spectroscopy and scanning electron microscopy. Tensile tests revealed the outstanding properties of composites prepared by in situ silanization method. The in situ silanization led to a better dispersion of the CNTs and the formation of chemical linkages between CNT surface and rubber and this became manifest in higher reinforcement of the rubber, higher crosslink densities, and a lower electrical percolation threshold. It was also shown that the in situ silanization is retarding the vulcanization reaction. POLYM. COMPOS., 36:2113–2122, 2015. © 2014 Society of Plastics Engineer     

Role and impact of surfactants in carbon nanotube dispersions and sorting

Carbon nanotubes (CNTs) are proving to be versatile nanomaterials that exhibit superior and attractive electrical, optical, chemical, physical, and mechanical properties. Different kinds of CNTs exist, and their associated properties have been actively explored and widely exploited from fundamental studies to practical applications. Obtaining high-quality CNTs in large volumes is desirable, especially for scalable electronic, photonic, chemical, and mechanical systems. At present, abundant but random CNTs are synthesized by various growth methods including arc discharge, chemical vapor deposition, and molecular beam epitaxy. An economical way to secure pristine CNTs is to disperse the raw soot of CNTs in solutions, from which purified CNTs are collected via sorting methods. Individual CNTs are generally hydrophobic, not readily soluble, requiring an agent, known as a surfactant to facilitate effective dispersions. Furthermore, the combination of surfactants, polymers, DNA, and other additives can enhance the purity of specific types of CNTs in confidence dispersions. With highly-pure CNTs, designated functional devices are built to demonstrate improved performance. This review surveys and highlights the essential roles and significant impacts of surfactants in dispersing and sorting CNTs.     

Mechanical properties and morphology of papers prepared from single-walled carbon nanotubes functionalized with aromatic amides

Carbon nanotube papers (CNT papers, also referred to as “buckypapers”) prepared from chemically functionalized single-walled CNTs are being investigated for their mechanical tensile properties. While the Young’s moduli are unaffected by the functionalization with diazonium salts of aniline or aromatic mono- and bis-amides tensile strengths of CNT papers are found to increase with a growing degree of functionalization, and more pronounced with a growing number of amide groups capable of hydrogen bonding. The importance of hydrogen bonding becomes evident after its inhibition through N-methylation of the amide groups, resulting in a distinct reduction of strength values. Scanning electron micrography indicates that a high degree of functionalization or a high number of amide group results in the formation of domains with aligned CNTs.     

Decoration of multi-walled carbon nanotubes by polymer wrapping and its application in MWCNT/polyethylene composites

ABSTRACT: We dispersed the non-covalent functionalization of multi-walled carbon nanotubes (CNTs) with a polymer dispersant and obtained a powder of polymer-wrapped CNTs. The UV-vis absorption spectrum was used to investigate the optimal weight ratio of the CNTs and polymer dispersant. The powder of polymer-wrapped CNTs had improved the drawbacks of CNTs of being lightweight and difficult to process, and it can re-disperse in a solvent. Then, we blended the polymer-wrapped CNTs and polyethylene (PE) by melt-mixing and produced a conductive masterbatch and CNT/PE composites. The polymer-wrapped CNTs showed lower surface resistivity in composites than the raw CNTs. The scanning electron microscopy images also showed that the polymer-wrapped CNTs can disperse well in composites than the raw CNTs.