Alternating Current Electrophoretic Deposition of Antibacterial Bioactive Glass-Chitosan Composite Coatings

Alternating current (AC) electrophoretic deposition (EPD) was used to produce multifunctional composite coatings combining bioactive glass (BG) particles and chitosan. BG particles of two different sizes were used, i.e., 2 μm and 20–80 nm in average diameter. The parameter optimization and characterization of the coatings was conducted by visual inspection and by adhesion strength tests. The optimized coatings were investigated in terms of their hydroxyapatite (HA) forming ability in simulated body fluid (SBF) for up to 21 days. Fourier transform infrared (FTIR) spectroscopy results showed the successful HA formation on the coatings after 21 days. The first investigations were conducted on planar stainless steel sheets. In addition, scaffolds made from a TiAl4V6 alloy were considered to show the feasibility of coating of three dimensional structures by EPD. Because both BG and chitosan are antibacterial materials, the antibacterial properties of the as-produced coatings were investigated using E. coli bacteria cells. It was shown that the BG particle size has a strong influence on the antibacterial properties of the coatings.     

碳纳米管材料在电磁屏蔽涂料中的应用

介绍了碳纳米管材料作为导电填料在电磁屏蔽涂料中的应用,并论述了碳纳米管的特性以及作为导电填料所进行的纯度、分散、偶联处理等分析,阐述了碳纳米管作为导电填料的电磁屏蔽涂料的发展趋势。     

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。     

分散剂对复合电刷镀Ni-P-碳纳米管工艺影响的研究

研究了羟乙基纤维素作分散剂对电刷镀Ni-P-碳纳米管工艺的影响。结果表明，羟乙基纤维素用量不同，电刷镀液中碳纳米管的颗粒尺寸有很大差别，不足或过量的羟乙基纤维素都影响碳纳米管的颗粒尺寸分布。超声搅拌时间长短、溶液pH值是影响电刷镀液中碳纳米管颗粒尺寸的另一个因素。当羟乙基纤维素用量为0．6g／L，溶液pH在5．7左右，碳纳米管颗粒平均粒径最小，刷镀层的碳纳米管成较好的分散状态，表面结晶更细致均匀。     

碳纳米管/苯丙乳液导电内墙涂料的制备

先利用混酸体系和3-氨丙基三乙氧基硅烷偶联剂(KH550)对多壁碳纳米管(MWCNTs)进行表面修饰,然后将修饰后的MWCNTs加入苯丙乳液中,成功制备了具有良好抗静电性能和力学性能的碳纳米管/苯丙乳液改性内墙涂料。利用透射电镜,对修饰前后的MWCNTs进行了热重分析。结果表明:KH550成功地接枝到MWCNTs表面,修饰后的MWCNTs能实现很好的分散。研究了MWCNTs用量对所制备涂料的导电性能、力学性能的影响。研究表明当MWCNTs添加量达到2.50%时,涂料的表面电阻最小,为1.42×107Ω,力学性能最佳。     

Multi-Directional Growth of Aligned Carbon Nanotubes Over Catalyst Film Prepared by Atomic Layer Deposition

The structure of vertically aligned carbon nanotubes (CNTs) severely depends on the properties of pre-prepared catalyst films. Aiming for the preparation of precisely controlled catalyst film, atomic layer deposition (ALD) was employed to deposit uniform Fe₂O₃ film for the growth of CNT arrays on planar substrate surfaces as well as the curved ones. Iron acetylacetonate and ozone were introduced into the reactor alternately as precursors to realize the formation of catalyst films. By varying the deposition cycles, uniform and smooth Fe₂O₃ catalyst films with different thicknesses were obtained on Si/SiO₂ substrate, which supported the growth of highly oriented few-walled CNT arrays. Utilizing the advantage of ALD process in coating non-planar surfaces, uniform catalyst films can also be successfully deposited onto quartz fibers. Aligned few-walled CNTs can be grafted on the quartz fibers, and they self-organized into a leaf-shaped structure due to the curved surface morphology. The growth of aligned CNTs on non-planar surfaces holds promise in constructing hierarchical CNT architectures in future.     

丙烯酸阳极电泳涂料的电泳涂装工艺研究

针对铝型材丙烯酸阳极电泳涂料,探讨了槽液固体含量、电泳电压、电泳时间、槽液pH等因素对漆膜外观和厚度的影响,确定了电泳涂装的最佳工艺参数:固体分5%～6%,电压120 V,电泳时间80～100 s,电泳槽液pH 7.6～8.1。     

微弧氧化-电泳沉积一步法制备羟基磷灰石/TiO2复合涂层

采用微弧氧化-电泳沉积一步法在钛表面生成了羟基磷灰石(HA)/TiO2复合涂层。探讨了电解液中乙醇含量的不同对涂层表面形貌、相组成及抗腐蚀能力的影响。结果表明:乙醇含量为25%时,涂层中HA的含量最高,其抗腐蚀能力最强。     

纳米Ni及碳纳米管对AP热分解的催化性能

分别用溶液还原法和化学沉淀法制备出了纳米NiNi／CNTs复合催化剂粒子,并用TEM,SEM,XRD,FT—IR对其进行了表征;运用差热分析（DTA）研究了纳米Ni及Ni／CNTs复合催化剂粒子对AP热分解性能的影响。结果表明。纳米Ni使AP热分解的高温分解峰温降低104．47C,纳米Ni／CNTs复合催化剂粒子可使AP热分解的高温分解峰温降低137．05℃,证明碳纳米管在纳米Ni对AP热分解的催化过程中起到了很好的助催化作用。     

Acid‐Resistant Coatings on Marble

Inorganic coatings are being developed to protect marble monuments and sculpture from weathering. In this work, the acid resistance of hydroxyapatite (HAP), calcium oxalate, and calcium tartrate coatings on Carrara marble were compared. To quantify the rate of attack on calcite, the pH of the solution was measured. This approach was validated by confirming that the rate of dissolution of untreated calcite inferred from the change in pH agrees with data in the literature. Calcium tartrate coatings were incomplete, and the mineral is so soluble that it offered no significant protection. Calcium oxalate forms coherent coatings, so it serves as a sacrificial coating in spite of having solubility comparable to that of calcite. HAP was deposited from aqueous solutions of 1M diammonium hydrogen phosphate (DAP), with or without millimolar additions of CaCl₂ (which improved coverage) and (NH₄)₂CO₃ (which resulted in cracking). The best HAP coatings remained porous; nevertheless, they were comparable to oxalate coatings in the short term and superior in the long term, reducing the dissolution rate by about 40%.     

阴极电泳涂装工艺管理入门提要

探讨了阴极电泳涂装工艺管理人员应具备的条件及其职责、工作方法和学习方法。     

碳纳米管负载纳米金属氧化物的研究进展

综述了碳纳米管负载纳米金属氧化物的制备方法以及当前研究的热点和存在的问题,重点论述了纳米金属氧化物沉积在碳纳米管表面上的方法及其相互作用机理,并展望了这类复合材料的应用前景.     

电泳沉积原理及其在陶瓷制备中的应用

本文介绍了电泳沉积(EPD)的原理,从胶体悬浮体系的DLVO经典静电稳定理论出发讨论了EPD的机理,综述了国外关于电泳沉积应用于陶瓷(包括传统瓷、技术瓷、超导瓷、生物瓷和复合瓷)坯体直接成型的研究进展。     

Removal of methylene blue from aqueous solution by electrophoretically deposited titania‐halloysite nanotubes coatings

Two‐component suspensions of titania and halloysite nanotubes (HNTs) were prepared in ethanol with 0.5 g/L (optimum concentration) of polyethyleneimine (PEI) and different wt% of HNTs. Kinetics of Electrophoretic deposition (EPD) decreased with increasing the HNTs content in suspensions due to their less mobility compared with titania particles. HNTs reinforced the microstructure of coatings and reduced or completely prevented from cracking during drying and heat‐treatment steps. Removal of methylene blue (MB) via adsorption by HNTs coatings was faster than its photocatalytic degradation by titania coating. Dispersion of HNTs (up to ≈30 wt%) in the matrix of titania resulted in the synergistic catalytic effect in MB removal. The synergistic effect was because of the shorter traveling distance of MB molecules adsorbed on HNTs toward the photocatalytic active site of titania particles in composite coatings. However, the synergistic effect was destroyed with increasing the HNTs content in coating. Difference between the amount of MB removed by titania and composite coatings increased at longer times (≥60 minutes). Mass transfer of MB adsorbed on HNTs toward the photocatalytic active sites of adjacent titania particles can compensate the decline in the mass transfer from solution at longer times.     

A Temperature Window for the Synthesis of Single-Walled Carbon Nanotubes by Catalytic Chemical Vapor Deposition of CH4 over Mo2-Fe10/MgO Catalyst

A temperature window for the synthesis of single-walled carbon nanotubes by catalytic chemical vapor deposition of CH₄ over Mo₂-Fe₁₀/MgO catalyst has been studied by Raman spectroscopy. The results showed that when the temperature is lower than 750 °C, there were few SWCNTs formed, and when the temperature is higher than 950 °C, mass amorphous carbons were formed in the SWCNTs bundles due to the self-decomposition of CH₄. The temperature window of SWCNTs efficient growth is between 800 and 950 °C, and the optimum growth temperature is about 900 °C. These results were supported by transmission electron microscope images of samples formed under different temperatures. The temperature window is important for large-scale production of SWCNTs by catalytic chemical vapor deposition method.     

Electrophoretic deposition of ZnO–CeO2 mixed oxide nanoparticles

ZnO–CeO₂ nanoparticles were synthesized by microwave combustion and deposited by electrophoretic deposition (EPD). The effect of using two different alcohols, ethanol and methanol, was investigated on EPD behavior and morphology of deposited film. Moreover, the effect of concentration of nanoparticles and applied voltage on the mass of deposit and the variation in the current density were investigated. With a change in the alcohol type, the surface morphology of deposition changed and some voids were observed on the deposition surface in ethanol. In all cases, with increasing concentration of nanoparticles in suspension, the number of developed cracks increased. Besides, a rise in voltage led to an increase in the number of cracks. The EPD processes in ethanol and methanol suspension were simulated over time using different zero boundary conditions. Hemi‐spherical morphology was seen for the nanoparticles deposited in ethanol. This kind of growth was simulated based on the changes in electrical field.     

Conductive, Polypyrrole Coating on Mullite/Alumina Fibers for Electrophoretic Deposition of Oxide Matrices

Mullite/alumina fibers (Nextel™ 720) have been rendered conductive for electrophoretic deposition (EPD) by coating with polypyrrole (Ppy) from an aqueous solution of pyrrole (Py). The polymer coating was characterized by thermogravimetric (TG) analysis, scanning electron microscopy (SEM), and conductivity measurements. The Ppy coating thickness is ∼0.1 μm and the fiber resistance 1–2 (kΩ/cm)/fiber tow. A maximum conductivity of ∼48 S/cm was achieved from a 0.005 M pyrrole solution. A Nextel 720/Al₂O₃ composite was synthesized using Ppy-coated fibers as the cathode in an EPD cell. The green and sintered microstructures of the resultant composites are reported.     

纳米碳管对CL-20热分解性能的影响

用DSC和TG研究了含纳米碳管的CL-20热分解特性。结果表明,纳米碳管的加入降低了CL-20的起始分解温度和分解峰温度,活化能由原来的184．3kJ／mol降低为172．2kJ／mol,放热量也由原来的2604．48J／g降低到2256．69J／g。同时,随着纳米碳管百分含量的增大,CL-20的起始分解温度、分解峰处温度、活化能以及放热量都逐步降低。     

碳纳米管的研究进展

碳纳米管是具有由石墨层片卷成的管状结构的一种新型纳米材料,拥有独特的物理化学、电学、热学和机械性能,以及十分诱人的应用前景。对碳纳米管的制备方法、性质、用途及研究新动向进行了简要的综述。     

碳纳米管负载铂-二氧化钌纳米颗粒催化剂的制备及表征

以多壁碳纳米管(MWNTs)为载体,采用化学还原法制备了多壁碳纳米管负载的铂-二氧化钌纳米颗粒催化剂(Pt-RuO2/MWNTs),并利用透射电镜(TEM)、电化学法等技术对该催化剂形貌和电化学性质进行了表征。结果表明,大小约为4～5nm的金属纳米颗粒均匀地分散在碳纳米管上,同时考察了该催化剂在铁氰化钾溶液中的循环伏安行为以及对该催化剂进行了电化学阻抗分析。