正十二硫醇自组装单层膜改善环氧涂层腐蚀防护性能的研究

通过在正十二硫醇自组装单层膜表面制备环氧树脂涂层的方法,在涂层/铜基体界面引入自组装界面层.采用X射线光电子能谱、电化学阻抗谱、阻抗-时间谱和相位角-时间谱等方法对硫醇自组装界面层及其对涂层腐蚀防护性能的影响进行了研究.结果表明,引入的自组装单层可极大地改善涂层的腐蚀防护性能.论文还对自组装单层改善涂层腐蚀防护性能的机理进行了探讨.     

TiO_2薄膜光催化降解亚甲基蓝(英文)

用常压气相沉积法镀膜制得的二氧化钛薄膜为催化剂,以紫外灯为光源,研究了亚甲基蓝的光催化降解。实验表明：镀膜时基片温度为２００℃;用铜线作为底物,在染料溶液中加Ｈ２Ｏ２,可提高光催化活性。     

Dynamical Mechanical Analysis and Curing Analysis of Fouling Release Coatings and Components

A commercially available fouling release (adsorbed foulants removed by shear flow) coating based on poly(dimethylsiloxane) and a commercial marine epoxy primer have been analyzed by diffusing wave spectroscopy and by thermal and dynamical mechanical methods. Diffusing wave spectroscopy reveals 7–9 distinct relaxation intervals over short (minutes) to long (20 hour) time scales. Several junctures of these intervals are shown to correlate with mechanically determined film formation parameters, such as set to touch times, tack free times, and dry through times. Thickness series of coatings made by casting illustrate similarities and distinct differences between the epoxy primer and poly(dimethylsiloxane)-based fouling release coating formulations. Several low temperature β transitions are resolved in the fouling release coatings in addition the α (T_g) transition in both formulations. A scaling analysis of the thickness series data shows that both the primer and the top coat exhibit a negative exponent for thickness; −0.77 for the epoxy; −1.2 for the top coat. Stress-strain experiments reveal further significant difference between these two types of elastomers. The elastic modulus for the epoxy is 1000-fold higher than for the topcoat. A small elastic modulus is thought to be key in the successful functioning of fouling release coatings. Analyses of substrate effects (wire mesh, fiberglass braid) and of coating or loading levels on dynamical mechanical properties, in comparison with thickness series of thin films are presented. The woven braid offers the advantage that it can be loaded more easily than can wire mesh substrates. The negative exponents show that thinner coatings may be more mechanically resilient than thicker coatings, as the ability to store and dissipate mechanical energy decreases as thickness increases.     

Disproportionation for growing copper nanowires and their controlled self-assembly facilitated by ligand exchange

The coating makes the wire bundle: High-quality free-standing copper nanowires have been successfully produced by disproportionation of Cu(+) in oleylamine. This provides an effective way to prepare high-quality copper nanowires, but also enriches synthetic routes to other nanostructures. These copper nanowires can self-assemble by surface ligand exchange of oleylamine with trioctylphosphine.     

Sonochemical synthesis of silver nanoparticles coated copper wire for low-temperature solid state bonding on silicon substrate

The rapid and efficient preparation of silver-copper wire by sonochemical assisted reduction method for high antioxidant performance and low melting temperature. Good ohmic contact between Ag-Cu wire and Si substrate can be achieved at temperature as low as 320℃.     

利多卡因选择性涂丝电极稳定性的研究

涂丝电极问世已有十多年,可用于离子选择性场效应管^[1]、高效液相色谱检测器^[2],但稳定性差。一般认为涂丝电极的金属与PVC膜之间的电子传递是由不可逆电对Pt|O₂,H₂O所引起^[3],因此可以认为,这一电对的不可逆性以及在使用过程中O₂、H₂O活度的变化是造成涂丝电极稳定性差的根本原因。     

Production and characterization of stable superhydrophobic surfaces based on copper hydroxide nanoneedles mimicking the legs of water striders

The present work reports a simple and economic route for production and characterization of stable superhydrophobic surfaces from thin copper layers coated on arbitrary solid substrates. The thin copper layer was anodized in a 2 M aqueous solution of potassium hydroxide to form a thin film of copper hydroxide nanoneedles; then the film was reacted with n-dodecanethiol to form a thermally stable Cu(SC12H25)2 superhydrophobic coating. The contact angle of the modified nanoneedle surface was higher than 150 degrees , and its tilt angle was smaller than 2 degrees . Furthermore, the surface fabricated on copper foil kept its superhydrophobic property after heating at 160 degrees C in air for over 42 h. This technique has also been applied for fabrication of copper wire with superhydrophobic submicrofiber coating to mimic water strider legs. The maximal supporting force of the superhydrophobic copper column has also been investigated in comparison to real water striders.     

Study of the fire resistant behavior of unfilled and carbon nanofibers reinforced polybenzimidazole coating for structural applications

With increasing interest in epoxy‐based carbon fiber composites for structural applications, it is important to improve the fire resistant properties of these materials. The fire resistant performance of these materials can be improved either by using high performance epoxy resin for manufacturing carbon fiber composite or by protecting the previously used epoxy‐based composite with some fire resistant coating. In this context, work is carried out to evaluate the fire resistance performance of recently emerged high performance polybenzimidazole (PBI) when used as a coating material. Furthermore, the effect of carbon nanofibers (CNFs) on fire resistant properties of inherently flame retardant PBI coating was studied. Thermogravimetric analysis of carbon/epoxy composite, unfilled PBI and nano‐filled PBI shows that the carbon/epoxy composite maintained its thermal stability up to a temperature of 400°C and afterwards showed a large decrease in mass, while both unfilled PBI and nano‐filled PBI have shown thermal stability up to a temperature of 575°C corresponding to only 11% weight loss. Cone calorimeter test results show that unfilled PBI coating did not improve the fire retardant performance of carbon/epoxy composite. Conversely, nano‐filled PBI coating has shown a significant improvement in fire retardant performance of the carbon/epoxy composite in terms of increased ignition time, reduced average and peak heat release rate and reduced smoke and carbon monoxide emission. These results indicate that addition of carbon nanofibers to inherently flame retardant coating can significantly be helpful for improving the fire resistance performance of composite materials even with low coating thickness. Copyright © 2013 John Wiley & Sons, Ltd.     

A sheathless poly(methyl methacrylate) chip-CE/MS interface fabricated using a wire-assisted epoxy-fixing method

Using a wire-assisted epoxy-fixing method, a sheathless CE/MS interface on a poly-(methyl methacrylate) (PMMA) CE chip has been developed. The sheathless chip-CE/MS interface utilized a tapered fused-silica tip and the electrical connection was achieved through a layered coating of conductive rubber. The wire-assisted method provided facile alignment of channels between the PMMA CE chip and an external capillary sprayer without the need for micromachining. Because the wire was in the channel during fixing, the risk of channel blockage by the epoxy was avoided. This chip CE device has minimal dead volume because the interstitial spaces were filled by a fast-fixing epoxy resin. The performance of the chip-CE-ESI-MS device was demonstrated with the analysis of peptide mixtures.     

Enhanced corrosion protection performance with MWCNT dispersed epoxy coating prepared under supercritical CO2 assistance

The corrosion protection performance of epoxy coatings could be enhanced by incorporation of nanofillers such as MWCNT. However, a homogeneous dispersion of MWCNT in epoxy polymer is still a teasing challenge. Herein, we report an environmentally benign single‐step supercritical CO₂ processing method to improve the dispersion of MWCNT in epoxy matrix in order to achieve an effective anticorrosive coating. The executed approach provides a cluster‐free uniform distribution of MWCNT in epoxy matrix as characterized with UV‐visible spectroscopy, Fourier transforms infrared spectroscopy, X‐ray diffraction, and surface analysis. The anticorrosive characteristics of MWCNT/epoxy coating were studied in NaCl as well as in photodegraded dye medium through electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements. We observed the remarkable corrosion of model metal substrate in photodegraded dye medium besides NaCl medium. In both mediums, the protection efficacy of MWCNT/epoxy coating was deduced from the stable impedance arcs in Nyquist plot and increased impedance modulus. The electrochemical impedance spectra were best fitted with equivalent circuits showing the higher values of pore resistance. Also, the MWCNT/epoxy coating exhibited a positive shift of corrosion potential and possessed a lower corrosion rate as compared with neat epoxy coating. More direct evidence of the excellent barrier properties for MWCNT/epoxy coating was visualized in SEM images. The obtained results implied that the superior dispersion of MWCNT into epoxy matrix significantly reduces the porosity of coating and inhibits the permeability of corrosive ions. We expect supercritical CO₂ assisted dispersion method can offer an efficient, cost‐effective, and industrially viable route to develop high performance protective coatings for varied commercialized applications.     

胶原/明胶的结构(构象)与性能研究V.铜离子与明胶中不同构象组分络合形态的研究

利用CM-52离子交换层析和无火焰原子吸收光谱法对明胶中铜离子与不同构象组分络合形态进行了研究。其研究结果表明:明胶中的铜离子是与明胶大分子中的不同构象(α、β和γ)组分中的游离基因以络合的形式稳定地存在着,铜离子与不同构象的络合能力大小可以排列成以下的顺序:(γ>β>α).金属铜与不同构象络合的能力是如此之强,以致明胶中微量的铜离子可以认为是明胶大分子结构中的一部分。     

环氧树脂的物理老化

本工作发展了补偿式示差扫描量热(CDSC)法,用于环氧树脂热焓松弛研究,实验结果证明CDSC法较DSC法灵敏并能提供更多的信息。用CDSC法研究了交联度对环氧树脂热焓松弛动力学的影响,计算了活化能,对结果进行了讨论。     

自由体积与亲水性对环氧涂层防护性能的影响

报道了涂层聚合物自由体积和亲水性对涂层腐蚀防护性能影响的初步研究结果.实验表明,相对于自由体积,树脂的亲水性是决定树脂吸水率的更主要因素.低亲水性涂层腐蚀防护性能的提高主要源自到达涂层/金属界面的水量的显著降低.但由于采用活性酯固化的环氧树脂涂层中水通道的尺寸相对较大,水合离子扩散较容易,因此该类涂层覆盖下的金属基体被润湿部分的腐蚀趋势反而较一般涂层为大.     

气相生长碳纤维对环氧树脂固化反应的影响及其复合物固化动力学研究

用示差扫描量热方法研究了气相生长碳纤维作为填料对4,4′-二氨基二苯甲烷四缩水甘油环氧树脂(TGDDM)/4,4′-二氨基二苯基砜(DDS)等温固化反应的影响.与纯环氧树脂一样,气相生长碳纤维复合物的固化反应也属于自催化反应类型.气相生长碳纤维对环氧树脂的固化反应动力学影响很小.固化反应的过程可以用一种修正过的自催化动力学模型来描述,在整个固化反应过程中纯TGDDM/DDS环氧树脂及其气相生长碳纤维复合物模型拟合得到的结果和实验数据相当一致.     

Facile fabrication of colored superhydrophobic coatings by spraying a pigment nanoparticle suspension

Superhydrophobic coatings were prepared by spraying a pigment nanoparticle suspension. By changing the type of pigment nanoparticles, the colors of the coating could be controlled. The particle size of the pigments, which determines the surface structure of the coatings, played an important role in exhibiting superhydrophobicity. The spray-coating process is applicable to a variety of materials (e.g., copper, glass, paper, coiled wire, and tied thread), and the superhydrophobicity was repairable.     

EFFECT OF CROSS-LINKING ON THE EXCESS ENTHALPY RELAXATION OF EPOXY

A method of comparative DSC technique is proposed for excess enthalpy relaxation study. The essential of the comparative DSC technique consists of comparing the enthalpy relaxation behavior of an aged sample with a quenched sample as reference. The accuracy of comparison is improved because of simultaneous measuring of the sample and reference which makes noise of the apparatus subtractive. This technique has been applied to studying the influence of crosslinking on the enthalpy relaxation behavior of epoxy resins. The effect of crosslinking on the kinetics of enthalpy relaxation of epoxy resins is discussed.     

THE MECHANISM OF CURE REACTION OF 4,4''''-DIAMINODIPHENYL METHANE WITH TETRAGLYCIDYL 4,4''''-DIAMINODIPHENYL METHANE EPOXY

The cure reaction of tetraglycidyl 4,4'-diaminodiphenyl methane (TGDDM) epoxy resin with 4,4'-diaminodiphenyl methane (DDM) has been studied by using DSC. Instead of one exothermic peak, two exothermic peaks, indicative of a complex reaction mechanism, are shown in the DSC curve of TGDDM-DDM mixtures in nonisothermal cure experiments when the content of DDM is lower than stoichiometric ratio. The result of the kinetic analysis of the cure reaction shows that the activation energy of the lower temperature exotherm peak is about 56 kJ/mol and that of the higher temperature exotherm peak is about 136 kJ/mol. The lower temperature cure reaction peak can be attributed to the primary amine-epoxide and secondary amine-epoxide reactions, and the higher temperature cure reaction peak can be attributed to the epoxide-hydroxy reaction under catalysis of tertiary amine in the TGDDM epoxy resin. Because the network density of the cured epoxy resin is determined by these two reactions, the content of DDM has little effect on the glass transition temperature of cured epoxy resin.     

硅烷改性纳米ZrO2对镁锂合金表面环氧树脂涂层耐蚀性能的影响

采用涂覆法在镁锂合金表面制备了含双-[3-(三乙氧基硅)丙基]四硫化物(KH-69硅烷)改性纳米ZrO₂的环氧树脂涂层. 通过傅里叶变换红外光谱(FTIR)、 扫描电子显微镜(SEM)和电化学阻抗谱(EIS)等手段表征了该涂层. 考察了KH-69硅烷改性纳米ZrO₂浓度对环氧树脂涂层耐蚀性能的影响. 结果表明, KH-69硅烷改性纳米ZrO₂能显著提高镁锂合金表面环氧树脂涂层的耐腐蚀性能, 其中1.0%(质量分数) KH-69硅烷改性纳米ZrO₂环氧树脂涂层具有较好的耐蚀性能. 在NaCl溶液中浸渍528 h后的低频阻抗值为1.6×10⁹ Ω·cm², 相比在NaCl溶液中浸渍240 h的纯环氧树脂涂层提高约5个数量级.     

Functionalized boron carbide for enhancement of anticorrosion performance of epoxy resin

In this study, epoxy coatings were modified by adding various compositions of B₄C particles. In order to achieve proper dispersion of particles in the epoxy coating and increasing chemical interactions between particles and polymeric coating, the surface of the B₄C particles was treated with γ‐(2,3‐epoxypropoxy) propytrimethoxysilane (KH560). The surface modification and microstructure of B₄C were characterized by Fourier transform infrared, X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. Electrochemical impedance spectroscopy was also used to evaluate the impedance of coatings. The results revealed that the KH560 not only enhanced the interaction between B₄C particles and epoxy resin but also exhibited a remarkable ability to improve the anticorrosion performance of epoxy resin. The epoxy coating with the 3 wt% B₄C‐KH560 particles exhibited the best anticorrosion performance, which can be attributed to the best uniform dispersion of the B₄C‐KH560 particles, and the particles effectively block the aggressive species (Cl⁻, O₂, and H₂O) from the coating.     

COORDINATION POLYMERIZATION OF BENZOTRIAZOLE ON THE SURFACE OF METALLIC COPPER

The coordination polymerization of benzotriazole with metallic copper has been investigated by infrared and X-ray photoelectron spectroscopies. We found that benzotriazole could react with copper (0) under mild conditions to form bis (benzotriazolato) copper (Ⅱ) and benzotriazolato copper (Ⅰ)which covered the surface of copper metal in the shape of polymeric materials. Since benzotriazole is of great interest as a ligand in that its presence in many biological system with metal ions, and is considered as a corrosion inhibitor, this work will be in favour of the study of protective corrosion.