四嗪改性碳纳米管环氧摩擦材料的研究

利用Diles-Alder反应,采用3,6-二氨基-1,2,4,5-四嗪对碳纳米管(CNTs)改性处理,考察了改性处理对碳纳米管表面结构、分散程度以及对环氧复合材料性能的影响,通过扫描电镜(SEM)、红外光谱(FTIR)Raman)分析了材料表面磨损形貌、多壁碳纳米管(MWNTs)分散程度以及碳纳米管结构变化,并探讨复合材料摩擦磨损机理、四嗪与碳纳米管反应机理.结果表明,通过四嗪化合物处理碳纳米管后,碳管表面连接活性基团氨基,结构形态发生改变,提高碳纳米管在基体中分散性和复合材料摩擦性能,8h处理MWNTs/EP比未处理MWNTs/EP复合材料摩擦系数降低6.5%,磨耗率降低71.4%.     

静电纺PA-SA/PET/MWNTs复合相变纤维的制备及储热性能研究

以聚对苯二甲酸乙二酯(PET)、棕榈酸和硬脂酸二元低共熔物(PA-SA)和多壁碳纳米管(MWNTs)为原料,通过静电纺丝的方法制备了新型的PA-SA/PET/MWNTs定形相变复合纤维。研究了强酸处理后的MWNTs对静电纺PA-SA/PET/MWNTs复合相变纤维的形貌结构和储热性能的影响。FT-IR光谱分析表明,强酸处理后在MWNTs的表面成功的引入了羧基(-COOH)官能团。SEM观察表明,随着MWNTs的加入,复合相变纤维表面沟槽变得更加明显且纤维直径明显增大。DSC分析表明了MWNTs的含量对复合相变纤维的熔化焓值和结晶焓值有一定的影响,对熔化温度和结晶温度没有显著性的影响。     

碳管长径比对MWNTs/PI复合薄膜介电性能的影响

采用混酸氧化法处理多壁碳纳米管(MWNTs),在不同处理时间下得到不同长径比的碳纳米管,并通过扫描电镜(SEM)对碳纳米管的形貌进行观察。以不同长径比的碳纳米管掺杂改性MWNTs/PI复合薄膜。运用体积排斥理论和渗滤理论预测分析了碳纳米管长径比对MWNTs/PI复合薄膜渗流阈值和介电常数的影响,并实测了MWNTs/PI复合薄膜的渗流阈值和介电常数,分析了理论预测与实测结果差异的原因。     

粉煤灰改性及其吸附含油废水的研究

研究了改性粉煤灰对含油废水的处理,探索了具体的改性工艺,利用FT-IR、XRD和SEM研究了改性后粉煤灰表面官能团、组分及表面形貌的变化。采用"三波长红外光谱法"的基本数学模型将红外光谱中透过率转化为吸光度算出对应的浓度,进而得出处理效果与浓度的关系;研究了粉煤灰/Ca(OH)2的配比、粉煤灰的改性温度、水灰比及搅拌时间对改性粉煤灰处理含油废水的影响。结果表明,当粉煤灰与Ca(OH)2的质量比为6∶1,粉煤灰的改性温度为600℃,水灰比为20∶1(mL/mg),搅拌时间为120min时,改性粉煤灰对含油废水的处理效果达到最好。     

多壁碳纳米管/SBS复合材料的制备及其渗流特性

以多壁碳纳米管(MWNTs)为导电填充物,以苯乙烯-丁二烯三嵌段共聚物热塑性弹性体(SBS)为基体材料,制备了导电高分子混合物薄膜,考察了采用不同的溶剂和成膜工艺对薄膜表面形貌的影响,同时通过电流/电压特性的测试,得到不同的MWNTs浓度下MWNTs/SBS混合材料的电渗流特性,其渗流区在6～9wt%之间.我们还初步研究了所得混合材料的电阻值受温度的影响,发现其温阻特性具有很强的时间迟滞性.     

聚丙烯腈超滤膜的等离子体接枝改性(Ⅰ)膜材料的表面结构与性能

利用低温等离子体技术对聚丙烯腈超滤膜进行了气相接枝改性，研究了不同等离子体处理功率、时间、不同单体温度、反应时间对接枝反应的影响，用红外光谱(FT—IR)和X光电子能谱(XPS)分析膜的表面结构组成及变化；用扫描电子显微镜观测了表面形态；考察了等离子体改性膜对蔗糖／水体系的分离性能。结果表明，对聚丙烯腈膜表面接枝丙烯酸单体，可使聚丙烯腈膜从超滤膜向纳滤级膜转变。     

载银多壁碳纳米管抗菌剂结构与性能的研究

以多壁碳纳米管(MWNTs)为载体,通过化学吸附的方法制备载银多壁碳纳米管(Ag/MWNTs)抗菌剂.用SEM、TEM、FT-IR、XRD对其表观形貌、结构进行了表征.结果表明,银离子(Ag+)被吸附到MWNTs的表面,通过抑菌环实验表明,Ag/MWNTs对大肠杆菌和金黄色葡萄球菌都有很好的抗菌效果.     

磷酸钙钛生物陶瓷膜诱导HAp沉积的研究

为了提高磷酸钙钛(CaTi4(PO4)6,简称CTP)陶瓷膜的生物活性,采用碱液对其进行了处理.研究了碱液的浓度、温度及处理时间时CTP诱导沉积HAp的影响.采用XRD、SEM检测其物相组成和表面形貌.实验结果表明:碱处理液的浓度、处理温度及时间对CTP陶瓷膜表面成分结构和诱导HAp沉积的能力有较大影响;陶瓷膜经浓度为1.0mol/L、温度为80℃的碱溶液处理2h,在仿生溶液中浸泡4d后有明显HAp沉积.说明碱处理对CTP陶瓷膜起到了生物活化改性的作用,有助于诱导HAp沉积,达到了提高生物活性的目的.     

PPy/MWNTs/GO复合材料的制备与电化学性能研究

以吡咯为单体,多壁碳纳米管和氧化石墨烯为模板,过硫酸铵为氧化剂,采用原位化学聚合法制备了聚吡咯/多壁碳纳米管/氧化石墨烯(PPy/MWNTs/GO)复合材料.利用傅里叶变换红外光谱(FTIR)、X射线衍射谱(XRD)、扫描电镜(SEM)、循环伏安法(CV)和电化学交流阻抗谱(EIS)对制备复合材料的结构、微观形貌和电化学性能进行了研究,探讨了多壁碳纳米管/氧化石墨烯比例、吡咯用量对复合材料电容性能的影响.研究结果显示,PPy/MWNTs/GO复合材料具有较大的比电容和良好的循环稳定性,且具有较小的电荷转移电阻,接近于理想的超级电容器用电极材料.     

低温等离子体接枝改性PVDF膜

采用低温等离子体接枝技术改性聚偏氟乙烯膜(PVDF),在PVDF膜表面引入疏水性单体苯乙烯,达到改变膜表面孔径的大小和孔径分布的目的.通过傅立叶红外光谱仪(FTIR-ATR)对改性前后的PVDF膜表面进行了结构分析,考察了PVDF膜接枝前后官能团的变化.采用示差扫描量热仪(DSC)分析了PVDF改性前后膜的孔径分布,考察了改性条件对膜孔径大小和分布的影响.通过扫描电子显微镜(SEM)和原子力显微镜(AFM)观测了PVDF膜改性前后表面形貌的变化.研究了接枝温度、接枝时间等接枝条件对PVDF改性膜纯水通量的影响.结果表明,随着照射时间和接枝时间的延长,PVDF改性膜的孔径分布变窄,纯水通量下降,接枝率提高.     

A composite of polyelectrolyte-grafted multi-walled carbon nanotubes and in situ polymerized polyaniline for the detection of low concentration triethylamine vapor

Multi-walled carbon nanotubes (MWNTs) grafted with sodium polystyrenesulfonate (NaPSS) were deposited on an interdigitated gold electrode decorated with a layer of positively charged poly(diallyldimethylammonium chloride) by a self-assembly method. Then polyaniline (PANI) was in?situ polymerized on the surface of the MWNTs to prepare a composite. The structure and morphology of the composite were investigated by Raman spectroscopy and scanning electron microscopy. The electrical responses of the composite to triethylamine vapor of low concentrations were measured at room temperature. It was found that the composite exhibited a linear response to the vapor in the range of 0.5-8?ppm with the highest sensitivity of ～80%, which is much higher than that of MWNTs and PANI separately, and an obvious synergetic effect was observed. In addition, the detection limit was as low as the ppb level, and reversible and relatively fast responses (t(90%)～200?s and ～10?min for sensing and recovery, respectively) were observed. The sensing characteristics are highly related to the gas responses of PANI, and a sensing mechanism considering the interaction of MWNTs and PANI was proposed.     

基于原子转移自由基聚合法制备多壁碳纳米管/Ag复合材料

在多壁碳纳米管(MWNT)表面键接可用于原子转移自由基聚合(ATRP)的引发剂,并以此引发甲基丙烯酸缩水甘油酯(GMA)在MWNT表面的ATRP.利用红外光谱(FT-IR)、核磁共振(<'1>H-NMR)和透射电镜(TEM)对接枝聚合物MWNT的结构和外观形貌进行了研究.接枝在MWNT表面的PGMA与过量的乙二胺发生开...     

Carbon nanotube arrays for optical design of amorphous silicon solar cells

Effective light trapping is essential for the conversion efficiency increase in thin film solar cells. Vertically aligned multiwalled carbon nanotubes (MWNTs) arrays with proper spacing form an ideal light trapping structure. In this work, we have demonstrated feasibility of the incorporation of MWNTs as back contact into amorphous silicon solar cells. Intrinsic amorphous silicon films were uniformly deposited onto vertically aligned MWNTs arrays. Scanning Electron Microscopy (SEM) was used to investigate the surface morphology of our films. The film surface area exposed to light was found to be increased dramatically due to the high-aspect ratio of MWNTs. Our findings open up a new way of managing light in thin film silicon solar cells by controlling the nano-geometry of MWNTs on substrates.     

Effect of pyrene-modified multiwalled carbon nanotubes on the properties of epoxy composites

The block polymer of poly(styrene-b-pyrene) (PS-b-PAH) containing pyrene units was successfully applied on the surface of multiwalled carbon nanotubes (MWNTs) and the properties of nanocomposites were enhanced. The morphology of the modified MWNTs was characterized by transmission electron microscopy (TEM), and the results showed that PS-b-PAH helped effectively the MWNTs to disperse well in epoxy matrices, and these dispersed MWNTs were stabilized by the pyrene modifier. The mechanical properties of the composites, such as impact toughness and flexural strength, and the electrical conductivity of the nanocomposites, are improved significantly after the treatment of the MWNTs using PS-b-PAH. The results show that the mechanical and electrical properties of the modified MWNTs/epoxy composites with PS-b-PAH are obviously superior to those of pristine MWNTs/epoxy composites. The enhanced interfacial interactions lead to good dispersion of MWNTs in epoxy matrices, thus enhancing the mechanical and electrical properties of the nanocomposites.     

Oxidation behavior of ferritic/martensitic steels in flowing supercritical water

The oxidation behavior of two Ferritic/Martensitic(F/M)steels including novel SIMP steel and commercial P91 steel were investigated by exposure to flowing deaerated supercritical water(SCW)at 700℃for up to 1000 h.The kinetic weight gain curves follow parabolic and near-cubic rate equations for SIMP and P91 steels,respectively.X-Ray Diffraction analysis showed the presence of magnetite and a spinel phase in flowing SCW for both steels.The morphology and structure of the oxide scales formed on these two steels were analyzed.The relationship between the microstructure and oxidation behavior and the reason that SIMP steel showed better oxidation resistance than P91 steel were discussed.     

Study on morphology and characterization of poly(mphenylene isophtalamide)/multi-walled carbon nanotubes composite nanofibers by electrospinning

Electrospinning technique is the main method of preparing polymer nanofiber simply, directly and continuously at present. In this work, electrospinning blend solution was prepared by in-situ polymerization using acid-modified multi-walled carbon nanotubes (MWNTs), m-phenylenediamine (MPD) and isophthaloyl chloride (IPC). And then composite nanofibers were prepared by electrospinning. MWNTs played an important role in nanofiber's properties. The effects of MWNTs on the morphology and characterization of the MWNTs/PMIA composite nanofibers were investigated. Scanning electron microscopy (SEM), thermal gravimetric analyzer (TGA), and X-ray diffraction (XRD) were utilized to characterize the MWNTs/PMIA nanofibers morphology and properties. The experimental results indicated that the nanofibers diameter decreased and solution dynamic viscosity increased with increasing MWNTs contents. XRD data demonstrated that PMIA composite nanofibers had the same crystal type as the pure PMIA nanofiber, and crystallinity was improved with increasing MWNTs loading. Transmission electron microscopy (TEM) was used to confirm MWNTs aligned along the axis of composite nanofibers.     

Morphology and electrical properties of polyamide 6/polypropylene/multi-walled carbon nanotubes composites

Morphology, electrical properties and conductive mechanisms of polyamide 6/polypropylene/muti-walled carbon nanotubes (PA6/PP/MWNTs) composites with varied compositions and different blending sequences were investigated. The MWNTs were found to be located preferentially in the PA6 phase in the composites, whatever the PA6 was continuous or dispersed phase. While the incorporation of MWNTs changed the dispersed PA6 phase from spherical to elongated or irregular shape. The PA6/PP/MWNTs (20/80/4) composite with a dispersed PA6 phase exhibited a higher electrical conductivity in comparison with the PA6/PP/MWNTs (50/50/4) composite which has a co-continuous phase and exhibits double percolation. This was due to the formation of a conductive MWNTs networks in the PA6/PP/MWNTs (20/80/4) composite as proved by means of field emission scanning electron microscopy and rheological measurements. The morphology and electrical properties of the PA6/PP/MWNTs (20/80/4) composites were significantly influenced by blending sequences. When blending 3.9 phr MWNTs with a pre-mixed PA6/PP/MWNTs (20/80/0.1) composite, the dispersed PA6 phase formed an elongated structure, which was beneficial to the electrical properties.     

The effect of constant electric field on the oxidation rate of massive zinc in supercritical water and the formation of zinc oxide nanocrystals

It is established that the rate of oxidation of a massive zinc plate by supercritical water (SCW) at 673 K and 23 MPa increases and the morphology of obtained ZnO nanocrystals changes when strength E of the constant electric field applied perpendicular to the plate increases from 0 to 286 kV/m. A decrease in the SCW density at the same temperature results in the formation of a more compact nanostructured ZnO layer, while the increase in E leads to loosening of structure in the inner part of the ZnO layer.     

The effects of synthesis procedures on the structure and morphology of multiwalled carbon nanotubes (MWNTs)/titania (TiO2) nanocomposites prepared by hydrothermal method

The nanocomposites of multiwalled carbon nanotubes (MWNTs)/titania (TiO₂) were prepared by direct growth of TiO₂ nanocrystals onto carboxyl-modified MWNTs under hydrothermal condition. The structure and morphology of TiO₂ nanocrystals growing on MWNTs were tuned by adjusting acidity, reaction temperature, and reactant ratio. The results showed that a uniform layer of anatase TiO₂ nanocrystals on MWNTs could be achieved at proper synthesis parameters. Flowerlike assemblage of rutile TiO₂ nanocrystals was dispersed on MWNTs. The formation mechanism of MWNTs/TiO₂ nanocomposites was further provided.     

Synthesis and characterization of processable multi-walled carbon nanotubes-sulfonated polydiphenylamine graft copolymers

Water soluble and processable nanocomposites composed of multi-walled carbon nanotubes (MWNTs) and poly(diphenylamine sulfonic acid) (PDPASA) are synthesized and characterized. Two types of methodologies are adopted. MWNTs are covalently functionalized with 2,5-diaminobenzene sulfonic acid (DABSA) and further in situ polymerized with diphenylamine-4-sulfonic acid (DPASA). This results in the formation of nanocomposites, MWNT(DABSA)-g-PDPASA, in which PDPASA is presented as the graft chains onto MWNTs. In another approach, DPASA is in situ polymerized in presence of unfunctionalized MWNTs, results in a nanocomposite in which MWNTs are present as entrapped mass in PDPASA matrix. Both nanocomposites are found to be water soluble and can form free standing films. The conductivity of MWNT(DABSA)-g-PDPASA and MWNT/PDPASA is found to be 1.25 mS x cm(-1) and 0.65 mS x cm(-1), respectively, which is higher than that of pristine PDPASA (0.25 x 10(-5) S x cm(-1)). The nanocomposites are characterized for their structure, morphology, optical and thermal properties.