埃洛石纳米管/壳聚糖复合材料的研究进展

首先对国内外埃洛石/壳聚糖复合材料的研究现状进行分析,然后介绍了埃洛石纳米管与壳聚糖的基本特点和应用情况。通过化学的视角综述了几种埃洛石/壳聚糖复合材料的制备方法,主要包括溶液共混法、溶剂浇铸法、乳化交联法、化学沉淀法、电化学沉积法、静电纺丝法、溶胶-凝胶法。同时阐述了所制得的复合材料的几种特性,发现其具有机械性能、生物相容性、无毒性和吸附性的优点,使得埃洛石纳米管/壳聚糖复合材料在生物医药、作为吸附剂治理水污染方面的应用有着广泛前景。最后,对该复合材料未来的研究发展予以展望。     

埃洛石纳米管/壳聚糖复合材料的研究进展

首先对国内外埃洛石/壳聚糖复合材料的研究现状进行分析,然后介绍了埃洛石纳米管与壳聚糖的基本特点和应用情况。通过化学的视角综述了几种埃洛石/壳聚糖复合材料的制备方法,主要包括溶液共混法、溶剂浇铸法、乳化交联法、化学沉淀法、电化学沉积法、静电纺丝法、溶胶-凝胶法。同时阐述了所制得的复合材料的几种特性,发现其具有机械性能、生物相容性、无毒性和吸附性的优点,使得埃洛石纳米管/壳聚糖复合材料在生物医药、作为吸附剂治理水污染方面的应用有着广泛前景。最后,对该复合材料未来的研究发展予以展望。     

钛酸纳米管改性高甲氧基果胶/壳聚糖复合膜性能的研究

本文通过流延法制备了高甲氧基果胶/壳聚糖复合膜,并以钛酸纳米管(Titanate nanotubes, TNTs)对其进行了改性。研究结果表明:TNTs的添加促使复合膜表面形成大量颗粒状结构,同时其力学性能、耐水性能和热稳定性上升。在TNTs添加量为0.15 g时,复合膜的拉伸强度、断裂伸长率达到最大,与添加TNTs前相比,分别增加了78.43%,51.23%;同时复合膜的吸水率、水蒸汽透过率则降到最低,与添加TNTs前相比,分别降低了18.18%和26.69%。当TNTs添加量达到0.20 g时,复合膜的各项性能有所回落。     

氮化硼纳米管问世

据报道，中科院物理所微加工实验室与日本物质材料研究机构合作，近日采用化学气相沉积法获得了N型的氮化硼半导体纳米管。     

氮化硼纳米管的合成与表征

以氧化铁和无定型硼粉为原料,反应气氛为碳气氛,在1 400℃下利用化学气相沉积法（CVD）制备出氮化硼纳米管。X射线研究表明,对应着六方氮化硼晶面的特征衍射峰非常清晰。采用扫描电子显微镜（SEM）对样品的结构与形貌进行表征,结果表明,样品属于一端开口的竹节状BN纳米管。     

以氧化钙为生长助剂合成氮化硼纳米管的研究

采用无定形B粉为主要原料、Fe2O3为催化剂,通过添加一定比例的生长助剂CaO,在氨气气氛下合成出氮化硼纳米管(BNNTs),结果表明:合成出的纳米管为多壁氮化硼纳米管(MWBNNTs),长度在数微米范围;CaO的加入使原料在高温下部分形成液相,促进B原子在催化原子Fe原子周围的聚集,并与NH3中的氮原子结合,最终形成BNNTs。     

阿司匹林壳聚糖-明胶载药微胶囊的制备及性能研究

以阿司匹林为囊芯,壳聚糖和明胶为壁材,采用乳化交联法制备了明胶-壳聚糖微胶囊,考察了芯壁比、水油体积比、乳化剂用量、交联时间等因素对微胶囊性能的影响.采用高效液相色谱法来测定微胶囊的载药量、包封率和释放性能.研究发现,当芯壁比为1∶1,水油体积比为1∶3,乳化剂Span-80用量为5％,交联时间为2h的条件下制备的微胶囊形状规整,载药量为47.99％,包封率为83.18％,且在人工肠液中具有明显的缓释效果.     

表面有丝状吸附物的氮化硼纳米管的制备

采用简单工艺,即：将块体氧化硼（B2O3）在氮气气氛中球磨后,在1200℃、流动的氨气中热处理,成功合成了表面有大量丝状吸附物的BN纳米管。纳米管为六方BN晶体且呈竹节形貌,其直径为80～120nm,长度近1μm。纳米管表面丝状的吸附层也是六方BN晶体,细丝的长度为100nm左右,直径不到10nm。     

合成工艺对氮化硼纳米管显微结构和性能的影响

采用无定型B粉为原料,在催化剂Fe2O3和CaO辅助作用下,控制反应气氛氨气的流量(150~200 mL/min),在1200℃下于真空管式炉中保温4 h,制备氮化硼纳米管(BNNTs)。采用透射电子显微镜(TEM)、X射线衍射(XRD)和傅里叶转换红外光谱分析(FTIR)等手段对产物的结构和形貌进行了表征,结果表明:所得产物为竹节状氮化硼纳米管(BNNTs),其晶体结构为六方氮化硼,外径约为35~100 nm,长度为数微米至数十微米。     

Novel sulfonated multi-walled carbon nanotubes filled chitosan composite membrane for fuel-cell applications

In the present study, multi-walled carbon nanotubes (MWCNTs) were sulfonated by 1,3-propane sultone and distillation–precipitation polymerization, respectively, and then incorporated into chitosan (CS) to prepare CS/MWCNTs composite membranes for fuel cell applications. CS/MWCNTs membranes show better thermal and mechanical stability than pure CS membrane due to the strong electrostatic interaction between the  SO₃H groups of MWCNTs and the  NH₂ groups of CS, which can restrict the mobility of CS chain. The sulfonated MWCNTs provide efficient proton hopping sites ( SO₃H,  SO₃⁻ …. ₃⁺HN ), thereby resulting in the formation of continuous proton conducting channels. The composite membranes with 5 wt % of MWCNTs modified by two different ways show a proton conductivity of 0.026 and 0.025 S·cm⁻¹, respectively. In conclusion, CS/MWCNTs membrane is a promising proton exchange membrane for fuel-cell applications. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47603.     

外壁荷电性质对双壁碳纳米管中水分子运动行为的影响

采用分子动力学模拟方法考察了双壁碳纳米管外壁荷电性质对孔道内水分子运动行为的影响。模拟结果显示：外壁荷电的双壁碳纳米管中水分子链呈现“双偶极”分布,由此将水分子的偶极翻转限制在碳纳米管的中部,避免了整条水分子链的偶极翻转,加速了水分子运动。外壁负载电荷也增强了水分子与碳纳米管之间相互作用,降低了水分子进入碳纳米管的能量壁垒,增强了碳纳米管内水分子内的氢键稳定性,这些均有利于水分子加速进入碳纳米管并在其中连续运动。上述结果从分子水平上揭示了碳管中水分子流动机理,为设计新型水纯化膜材料提供了有益的启示。     

Effect of degree of substitution and molecular weight of carboxymethyl chitosan nanoparticles on doxorubicin delivery

The aim of this study was to evaluate the potential of carboxymethyl chitosan (CM‐chitosan) nanoparticles as carriers for the anticancer drug, doxorubicin (DOX). Different kinds of CM‐chitosan with various molecular weight (MW) and degree of substitution (DS) were employed to prepare nanoparticles through ionical gelification with calcium ions. Factors affecting nanoparticles formation in relation to MW and DS of CM‐chitosan were discussed. By the way of dynamic light scattering (DLS), TEM, and atomic force microscopy (AFM), nanoparticles were shown to be around 200–300 nm and in a narrow distribution. FTIR revealed strong electrostatic interactions between carboxyl groups of CM‐chitosan and calcium ions. DOX delivery was affected by the molecular structure of CM‐chitosan. Increasing MWs of CM‐chitosan from 4.50 to 38.9 kDa, DOX entrapment efficiency was enhanced from 10 to 40% and higher DS slightly improved the load of DOX. In vitro release studies showed an initial burst followed by an extended slow release. The DOX release rate was hindered by CM‐chitosan with high MW and DS. These preliminary studies showed the feasibility of CM‐chitosan nanoparticles to entrap DOX and the potential to deliver it as controlled release nanoparticles. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4689–4696, 2006     

In situ grown carbon nanotubes on carbon paper as integrated gas diffusion and catalyst layer for proton exchange membrane fuel cells

In situ grown carbon nanotubes (CNTs) on carbon paper as an integrated gas diffusion layer (GDL) and catalyst layer (CL) were developed for proton exchange membrane fuel cell (PEMFC) applications. The effect of their structure and morphology on cell performance was investigated under real PEMFC conditions. The in situ grown CNT layers on carbon paper showed a tunable structure under different growth processes. Scanning electron microscopy (SEM) and Brunauer–Emmett–Teller (BET) demonstrated that the CNT layers are able to provide extremely high surface area and porosity to serve as both the GDL and the CL simultaneously. This in situ grown CNT support layer can provide enhanced Pt utilization compared with the carbon black and free-standing CNT support layers. An optimum maximum power density of 670 mW cm⁻² was obtained from the CNT layer grown under 20 cm³ min⁻¹ C₂H₄ flow with 0.04 mg cm⁻² Pt sputter-deposited at the cathode. Furthermore, electrochemical impedance spectroscopy (EIS) results confirmed that the in situ grown CNT layer can provide both enhanced charge transfer and mass transport properties for the Pt/CNT-based electrode as an integrated GDL and CL, in comparison with previously reported Pt/CNT-based electrodes with a VXC72R-based GDL and a Pt/CNT-based CL. Therefore, this in situ grown CNT layer shows a great potential for the improvement of electrode structure and configuration for PEMFC applications.     

Stress simulation of carbon nanotubes in tension and compression

Based on a continuum shell model, a structural mechanics approach is presented to simulate stress-strain behavior of carbon nanotubes (CNTs). The nanoscale continuum theory is established to directly incorporate the Morse potential function into the constitutive model of CNTs. According to the present model, the mechanical properties of both zigzag and armchair tubes are investigated. The result shows that the atomic structures of CNTs have a significant influence on the stress-strain behavior. The armchair zigzag tube exhibits larger stress-strain response than the zigzag tube under tensile loading, but its relationship turns over between the tension and compression deformations. The theoretical approach supplies a set of very simple formulas and able be serve as a good approximation on the mechanical properties for CNTs.     

High-crystallization polyoxymethylene modification on carbon nanotubes with assistance of supercritical carbon dioxide: Molecular interactions and their thermal stability

As a typical engineering plastic and high-crystallization polymer, polyoxymethylene (POM) has been successfully wrapped on single-walled carbon nanotubes (SWCNTs) using a simple supercritical carbon dioxide (SC CO₂) antisolvent-induced polymer epitaxy method. The characterization results of scanning electron microscopy (SEM) and transmission electron microscopy (TEM) reveal that the SWCNTs are coated by laminar POM with the thicknesses of a few nanometers. The polymer adsorption on CNTs via multiple weak molecular interactions of CH groups with CNTs has been identified with FTIR and Raman spectroscopy. The experimental results indicate that the decorating degree of POM on the surface of CNTs increases significantly with the increase of SC CO₂ pressure, and accordingly the dispersion of SWCNT modified by POM at higher pressure are more excellent than that of obtained at lower pressure. Further the processing stability of POM/CNTs composites are investigated by differential scanning calorimetry and thermogravimetric analysis. The experimental results obtained show that their thermal stability behavior is closely related to surface properties of CNTs. Apparently, the composites with POM-decorating SWCNTs as the filler shows higher melting points compared to the POM composites with pristine SWCNTs as the filler. Therefore, we anticipate this work may lead to a controllable method making use of peculiar properties of SC CO₂ to help to fabricate the functional CNTs-based nanocomposites containing highly crystalline thermoplastic materials such as POM.     

纳米管固定化生物分子及其应用

综述了纳米管固定化生物分子的几种主要方法,如交联法、吸附法、包埋法等,并简要地介绍了纳米管固定化生物分子在生物传感、生物催化和生物分离等领域的应用。     

Functionalization of multiwalled carbon nanotubes by reversible addition fragmentation chain-transfer polymerization

In this study, a new way was used to chemically synthesize polymer-connected MWNT nanocomposites. Reversible addition fragmentation chain-transfer (RAFT) agent was successfully grafted onto the surface of multiwalled carbon nanotubes (MWNTs). Polystyrene (PS) chains were successfully grafted from the surface of MWNTs via RAFT process by using RAFT agent immobilized on MWNTs. FTIR, XPS and TGA were used to determine chemical structure and the grafted PS quantities of the resulting products. TEM images of the samples provide direct evidence for the formation of a core-shell nanostructure, i.e. the MWNT coated with polymer layer and the solubility be improved.     

醇类在Pt-TiO2纳米管上的光催化制氢

采用溶胶-凝胶法(sol-gel)、水热法和光沉积法制备了铂(Pt)负载量为0.5%的二氧化钛纳米管催化剂(TNT),并利用甲醇等醇类制氢。结果表明,所制备的催化剂具有良好的管状形貌;甲醇(CH₃OH)和水在同等数量级上共同吸附在催化剂表面9 h后制氢效率最高,核磁共振氢谱(¹H NMR)分析表明甲醇裂解制氢过程在催化剂表面进行,因氢键束缚产生的过渡产物无法脱附直至形成CO₂;醇类碳链长度、支链数目、羟基数目以及苯环基团等都对醇类制氢有着不同的影响,制氢过程中醇分子与催化剂的吸附作用强弱和醇分子被羟基植入的难易程度是制氢效果差异的主要原因。     

MFC聚苯胺碳纳米管阳极电化学法制备及其性能

引言经济的高速可持续发展,迫切需要新能源和可再生能源的研究和开发。而微生物燃料电池(MFC)是利用电化学方法将微生物代谢能转化为电能的一种新型能源技术[1]。虽然MFC功率密度和输出电压近年来有了很大提高,但和普通氢燃料电池相比,MFC的库仑效率和输出功率都较低,实现MFC技术的商业化应用还需要多方面技术研