One-Step Cutting of Multi-Walled Carbon Nanotubes Using Nanoscissors

Nano-Micro Letters - A novel, simple and effective one-step method has been developed to cut the conventional long and entangled multi-walled carbon nanotubes (MWCNTs) with nanoscissors. The...     

木聚糖/多壁碳纳米管复合水凝胶的制备及性能

以木聚糖和改性碳纳米管为原料,采用半互穿网络方法制备了一系列不同碳纳米管含量的木聚糖/多壁碳纳米管复合水凝胶;利用扫描电镜及红外光谱对凝胶的微观结构及化学结构进行了表征,研究了碳纳米管的含量对凝胶的微观结构及力学性能的影响,考察了凝胶的pH敏感性以及碳纳米管含量和交联剂用量对溶胀率的影响,研究了该凝胶对亚甲基蓝的吸附行为。结果表明,随着改性碳纳米管含量的增加,凝胶的抗压性能提高,溶胀率先增大后减小,但交联剂用量的增加会使凝胶溶胀率明显减小。改性碳纳米管的引入使凝胶的pH敏感性增强、孔径均匀、吸附性能提高。吸附研究表明该木聚糖/多壁碳纳米管复合水凝胶是一种良好的阳离子吸附剂。     

多壁碳纳米管/聚乳酸复合超细纤维的制备及性能

通过静电纺丝法制备出多壁碳纳米管（MWNTs）增强聚乳酸（PLA）复合超细纤维膜。用扫描电镜、透射电镜、差示扫描量热仪、热重分析仪对MWNTs/PLA复合超细纤维进行了表征,并进行了拉伸测试。结果表明,MWNTs分散于PLA纤维中,随着MWNTs含量的增加,纤维平均直径先减小后增大,MWNTs的加入会降低PLA的结晶度...     

多壁碳纳米管/聚氯乙烯复合材料的制备及性能

通过溶液混合法可以简单地制得多壁碳纳米管/聚氯乙烯复合材料。体积电阻率、拉伸强度等测试结果表明,随着碳纳米管含量的增加,碳纳米管在聚合物基体中的分散性降低,所得聚氯乙烯复合材料的体积电阻率呈非线性降低趋势,拉伸强度则呈先增加后降低的变化规律。碳纳米管含量为1%~2.5%(质量分数,下同)时所得复合材料的导电性和拉伸强度均较纯聚氯乙烯有较大改善。     

聚乙烯亚胺功能化多壁碳纳米管的制备及对硫化氢气体的吸附性能

采用聚乙烯亚胺(PEI)对多壁碳纳米管(MWCNTs)进行功能化,并用红外、热失重、拉曼对聚乙烯亚胺改性的碳纳米管进行表征,红外光谱和热失重曲线表明聚乙烯亚胺成功键合到多壁碳纳米管上,拉曼光谱中碳纳米管的D/G比(D峰面积比G峰面积)从0.8398变成1.2364,说明碳纳米管的缺陷程度明显增加,这种缺陷的增加是由碳纳米管表面引入了PEI导致的。利用紫外吸收光谱探究聚乙烯亚胺功能化的多壁碳纳米管(MWCNTs-PEI)对硫化氢的吸收及其可逆性。MWCNTs-PEI对硫化氢的首次吸收效率为0.16 mmol/g,2次重复吸收后仍有0.13 mmol/g的吸收效率,说明MWCNTs-PEI能够对硫化氢起到吸收作用并且具有很好的可逆性。     

Machinablity of Hybrid Natural Fiber Composite with and without Filler as Reinforcement

The filler materials are reinforced along with natural fibers in the composite to improve the quality and property of the component materials based on the requirements and its applications. In this paper, hybrid natural fiber composites were developed with and without filler materials as reinforcement. The developed hybrid natural fiber composites are machined using abrasive water jet cutting process with three different cutting parameters. The influences of cutting parameters are evaluated with respect to the kerf wall inclination, material removal rate, and surface roughness. The surface morphology was also studied to infer the basic mechanism involved during composite machining. The hybrid fiber composite with filler has proved that it can produce good engineering component without delamination and fiber pullouts during machining.     

酸处理碳纳米管/PBO复合材料的制备与表征

用原位聚合法成功地制备了碳纳米管/聚对苯撑苯并双口恶唑(PBO)复合材料。用FT-IR、XPS、SEM和AFM对碳纳米管和所制备的复合材料进行了表征,结果表明,碳纳米管的酸处理效果好,表面含有C-O、COOH等极性官能团;复合材料中碳纳米管在聚合物基体中分散均匀,两相界面间存在较强的作用力。     

多壁碳纳米管/天然橡胶复合材料的结构和动态性能

以HNO₃/H₂SO₄改性的多壁碳纳米管（CNTs）为原料,制备多壁碳纳米管（CNTs）/天然橡胶（NR）复合材料,研究了在NR中填充CNTs对其力学性能、动态性能、Payne效应、压缩生热和损耗因子的影响。结果表明:经HNO₃/H₂SO₄混合酸改性的CNTs表面含有氢原子、含氧官能团和自由基,增强了大管径CNTs与橡胶基体间界面结合,如物理吸附、氢键作用、化学结合等。其结果是,随着CNTs管径的增大,对复合材料的补强作用增强,压缩温升小,其Payne效应也降低;损耗因子（tanδ）越大压缩温升越高;填充不同管径CNTs的份数越大,碳纳米管之间的平均距离减小,更易形成聚集体,其复合材料的Payne效应越大。     

多壁碳纳米管/环氧树脂复合材料的制备及性能

以化学修饰法在多壁碳纳米管上成功接枝了四乙烯五胺,并用溶液共混法制备出多壁碳纳米管/环氧树脂复合材料。使用电子拉力试验机、Agilent 4294A、差示扫描量热(DSC)和扫描电镜(SEM)对复合材料进行研究。结果表明,修饰后的碳纳米管能均匀分散在基体中,添加经修饰后的碳管比添加原始碳管更能提高环氧树脂的力学强度、热稳定性和介电性能。当经修饰后的碳管质量分数为1.5%时拉伸强度和断裂伸长率分别增加了84.3%和150%,玻璃化转变温度提高了32℃,复合材料的介电常数高达25.8。     

Adsorption of Dinitrogen Tetroxide (N2O4) on Multi-walled Carbon Nanotubes (MWCNTs)

The adsorption of dinitrogen tetroxide (N₂O₄) on multi-walled carbon nanotubes (MWCNTs) has been studied by FT-IR, Raman and X-ray photoelectron spectroscopy (XPS). The N₂O₄ adsorption is fully reversible, and after the desorption there is no evidences of MWCNTs nitration. Instead, the MWCNTs have been found oxidized by the action of N₂O₄. By thermogravimetric analysis (TGA) about 5% by weight of oxygenated groups have been found. Thermal analysis has revealed that MWCNTs having a surface area of 275 m²/g are able to reversibly adsorb about 25% by weight of N₂O₄, a value comparable to that observed for certain active carbons.     

Integrated Uniformly Microporous C4N/Multi-Walled Carbon Nanotubes Composite Toward Ultra-Stable and Ultralow-Temperature Proton Batteries

Benefiting from the proton's small size and ultrahigh mobility in water, aqueous proton batteries are regarded as an attractive candidate for high-power and ultralow-temperature energy storage devices. Herein, a new-type C₄N polymer with uniform micropores and a large specific surface area is prepared by sulfuric acid-catalyzed ketone amine condensation reaction and employed as the electrode of proton batteries. Multi-walled carbon nanotubes (MWCNT) are introduced to induce the in situ growth of C₄N, and reaped significantly enhanced porosity and conductivity, and thus better both room- and low-temperature performance. When coupled with MnO₂@Carbon fiber (MnO₂@CF) cathode, MnO₂@CF//C₄N-50% MWCNT full battery shows unprecedented cycle stability with a capacity retention of 98% after 11 000 cycles at 10 A g⁻¹ and even 100% after 70 000 cycles at 20 A g⁻¹. Additionally, a novel anti-freezing electrolyte (5 m H₂SO₄ + 0.5 m MnSO₄) is developed and showed a high ionic conductivity of 123.2 mS cm⁻¹ at -70 °C. The resultant MnO₂@CF//C₄N-50% MWCNT battery delivers a specific capacity of 110.5 mAh g⁻¹ even at -70 °C at 1 A g⁻¹, the highest in all reported proton batteries under the same conditions. This work is expected to offer a package solution for constructing high-performance ultralow-temperature aqueous proton batteries.     

Synthesis of Heterogenous Multi-Walled Carbon Nanotubes in a Carbon Arc in Water

Boron-doped multi-walled carbon nanotubes (MWCNTs) were generated by arc discharge in water by using B-doped graphite electrodes. The product morphology was studied by SEM and HRTEM microscopy. The electronic features were determinated by Raman and EELS spectroscopy. Optical emission spectroscopy (OES) was used to evaluate the temperature and C₂ content distributions in arc plasma.     

多壁碳纳米管对聚丙烯韧性和阻燃的影响

通过添加表面活性剂和两步法的加工工艺,研究了未进行任何预处理的多壁碳纳米管对聚丙烯力学性能、阻燃性能和电性能的影响。结果显示,聚丙烯/多壁碳纳米管复合材料在具有一定抗静电能力的同时,其缺口冲击强度可达47.3 k J/m2,相对于纯的聚丙烯提高了414%。在聚丙烯溴系阻燃体系中,多壁碳纳米管比超导炭黑更适合作为导电填料,在燃烧时能抑制火焰和滴落物的产生,并能有效缩短续焰时间t1和t2,最终使复合材料具备抗静电性能,且达到V-0阻燃级别。     

碳纳米管-纳米ZnO改性环氧复合材料的制备与性能

采用混酸对多壁碳纳米管(MWNT)进行羧基化产生-COOH、-OH等反应性基团,通过纳米ZnO与活性基团的共价连接得到MWNT-纳米ZnO复合结构。应用熔融共混法分别制备不同填料的环氧树脂复合材料,并通过FTIR、XRD、SEM、UV-Vis等进行测试表征。结果表明:经酸化处理及纳米ZnO复合后碳纳米管与环氧树脂的结合加强,复合材料的性能提高,其中当填料添加为2%(质量分数)时,羧基化和ZnO-MWNT/EP复合材料的导热率分别达到0.604W/(m·K)、0.636W/(m·K),与环氧树脂自身相比分别提高168%、177%;纳米ZnO赋予复合材料在一定波长范围的紫外吸收性,改善了材料的抗紫外老化性能。     

The Effect of Hydrothermal Aging on the Low-Velocity Impact Behavior of Multi-Walled Carbon Nanotubes Reinforced Carbon Fiber/Epoxy Composite Pipes

Chemical transmission lines, petroleum and natural gas lines, pressure vessels, and pipes used in thermal facilities are expected to maintain their mechanical properties for many years without being damaged and not to be corroded in working conditions. The composite materials are the right candidate for these harsh conditions due to their superior properties. Reinforcement of nanoadditives to composite materials improves both the mechanical properties and the resistance to environmental conditions, thereby increasing the lifetime. In this study, multi-walled carbon nanotube (MWCNT) reinforced [±?55°] carbon fiber/epoxy composite pipes produced with filament wound method were used. It was hydrothermally aged in 80 °C distilled water for 1, 2, 3 weeks in order to examine the effect of environmental conditions. In order to investigate its resistance against loads that may occur in working conditions, ring tensile tests (ASTM D 2290–16 procedure A), and low-velocity impact tests at 5, 10, 15 J, energy levels were carried out. The effect of hydrothermal aging on neat and MWCNT added epoxy composite had been examined by considering the aging period. Consequently, the impact resistance of neat and MWCNT added samples decreased with the aging process. Besides, tangential tensile strength loss was 17% in MWCNT reinforced sample and 13% in the neat sample.

     

Study of Composite Interface Fracture and Crack Growth Monitoring Using Carbon Nanotubes

Interface fracture of woven fabric composite layers was studied using Mode II fracture testing. Both carbon fiber and E-glass fiber composites were used with a vinyl ester resin. First, the single-step cured (i.e., co-cured) composite interface strength was compared to that of the two-step cured interface as used in the scarf joint technique. The results showed that the two-step cured interface was as strong as the co-cured interface. Carbon nanotubes were then applied to the composite interface using two-step curing, and then followed by Mode II fracture testing. The results indicated a significant improvement of the interface fracture toughness due to the dispersed carbon nanotube layer for both carbon fiber and E-glass fiber composites. The carbon nanotube layer was then evaluated as a means to monitor crack growth along the interface. Because carbon nanotubes have very high electrical conductivity, the electrical resistance was measured through the interface as a crack grew, thus disrupting the carbon nanotube network and increasing the resistance. The results showed a linear relationship between crack length and interface resistance for the carbon fiber composites, and allowed initial detection of failure in the E-glass fiber composites. This study demonstrated that the application of carbon nanotubes along a critical composite interface not only improves fracture properties but can also be used to detect and monitor interfacial damage.     

嵌段共聚物非共价修饰碳纳米管/环氧纳米复合材料的性能

采用原子转移自由基聚合法(ATRP)合成了嵌段共聚物聚苯乙烯/苯乙烯基芘丁酸酯(PS-b-PAH),并将其对碳纳米管(MWNTs)进行非共价键表面修饰(PS-b-PAH/MWNTs),采用浇注成型法制备了MWNTs/环氧树脂(EP)纳米复合材料。透射电镜表明,嵌段聚合物PS-b-PAH包覆于MWNTs表面,形成有机包覆层的厚度为17.7nm。嵌段聚合物修饰有效地改善了碳纳米管在环氧基体中的分散性并提高了PS-b-PAH/MWNTs/EP纳米复合材料的导电性。当PS-b-PAH/MWNTs质量分数为0.8%时,复合材料的阈渗值pc=0.124%(质量分数),较MWNTs/EP(pc=0.625%)降低了5倍;电导率为10-3S/cm,较MWNTs/EP高了3～4个数量级。     

Mass-Spectrometric Investigation of Gases Evolved from Fluorinated Multi-Walled Carbon Nanotubes at Heating

The mass-spectrometric investigation of the gases evolved from fluorinated multi-walled carbon nanotubes under heating was carried out. It was shown that in temperature interval from 20°C to 120°C the gases are composed predominantly of CO₂, CO and H₂O. Molecules of COF₂ can be finding in gas phase of products of decomposition at 120-300°C. Molecules of CF₄ and C₂F₆ realized from fluorinated nanotubes at 300-450°C.     

多壁碳纳米管的化学修饰及其增强环氧树脂复合材料的性能

研究原生多壁碳纳米管和己二胺修饰的多壁碳纳米管分别对环氧树脂的增强作用。用SEM、FT-IR及XPS对修饰前后的碳纳米管进行的表征表明,所用的方法可以在碳纳米管的表面接上己二胺。研究发现,修饰后的碳纳米管比原生碳纳米管对环氧树脂有更明显的增强作用。修饰后的碳管含量为2%时,拉伸强度、断裂伸长率和冲击强度比纯环氧树脂分别提高79.7%、160.4%和188.2%。