铜表面修饰硅烷膜在碱性溶液中的耐蚀性能研究

为了提高铜的耐蚀性,用自组装技术在铜表面上制备了3-巯基丙基三甲氧基硅烷(MPTS)自组装膜. 利用红外光谱和扫描电子显微镜研究了该膜的结构,运用极化曲线和交流阻抗图谱等电化学方法考察了 MPTS膜在0.5 mol/L NaOH溶液中对铜电极的缓蚀性能.结果表明,MPTS在铜表面可能以化学吸附方式强烈吸附到铜表面, 同时在表面以Si-O-Si键自我交联形成了线性低聚物, MPTS浓度越高, 其膜更致密.与裸铜电极相比,经MPTS修饰后的铜的腐蚀电位正移200 mV, 腐蚀电流降低一个数量级,其缓蚀效率为86.5%.     

Polymer brush coatings for combating marine biofouling

A variety of functional polymer brushes and coatings have been developed for combating marine biofouling and biocorrosion with much less environmental impact than traditional biocides. This review summarizes recent developments in marine antifouling polymer brushes and coatings that are tethered to material surfaces and do not actively release biocides. Polymer brush coatings have been designed to inhibit molecular fouling, microfouling and macrofouling through incorporation or inclusion of multiple functionalities. Hydrophilic polymers, such as poly(ethylene glycol), hydrogels, zwitterionic polymers and polysaccharides, resist attachment of marine organisms effectively due to extensive hydration. Fouling release polymer coatings, based on fluoropolymers and poly(dimethylsiloxane) elastomers, minimize adhesion between marine organisms and material surfaces, leading to easy removal of biofoulants. Polycationic coatings are effective in reducing marine biofouling partly because of their good bactericidal properties. Recent advances in controlled radical polymerization and click chemistry have also allowed better molecular design and engineering of multifunctional brush coatings for improved antifouling efficacies.     

Structure-related behavior of hybrid organic–inorganic materials prepared in different synthesis conditions from Zr-based NBBs and 3-methacryloxypropyl trimethoxysilane

The copolymerization of zirconium oxo-clusters (Zr12) with 3-methacryloxypropyl (trimethoxy)silane (MPTMS), using a Si/Zr molar ratio of 4, was investigated. The hybrid samples were prepared both with and without organosilane prehydrolysis. Differential scanning calorimetry (DSC), multinuclear liquid, and solid state NMR analyses and Fourier transform infrared (FTIR) spectroscopy were used to characterize the hybrid materials and study the influence of synthesis conditions on condensation and polymerization. The degree of condensation (DOC) of the silsesquioxane network and the polymerization yield are generally high. However, the organosilane prehydrolysis step leads to the reduction of the extent of phase interaction, thus favoring the phase separation between silica-zirconia-based domains. Dynamic mechanical spectroscopy (DMS) analyses were performed on the hybrid polymers obtained by means of the two synthetic pathways. The sample prepared without the organosilane prehydrolysis step presents a higher glass transition temperature (T_g) than the one with silane prehydrolysis. By heating above the T_g, the samples retain shape and size, due to the lack of viscous flow. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Cellulose nanocomposites based on silane reinforced 3-butynoate-substituted zirconium-oxocluster copolymers: Mechanical,thermal and hydrophobic properties

Silica based cellulose nanocomposites obtained from (3-mercaptopropyl)trimethoxysilane or vinyltrimethoxysilane and 3-butynoate-substituted zirconium-oxoclusters were prepared and their surface morphology, wettability, and thermo-mechanical properties were studied. The composites showed a hydrophobic surface, high strength, and resistance to thermal degradation and aging; in comparison to the untreated paper they required a higher temperature to activate combustion and generated less heat during all thermal processes.     

Immobilization of horseradish peroxidase on self-assembled (3-mercaptopropyl)trimethoxysilane film: Characterization, direct electrochemistry, redox thermodynamics and biosensing

Highly organized (3-mercaptopropyl)trimethoxysilane (3-MPT) films have been prepared via self-assembled coupled with sol–gel linking technology. Horseradish peroxidase (HRP) is successfully immobilized onto the densely packed three-dimensional (3D) 3-MPT network and the direct electrochemistry of HRP is achieved without any electron mediators or promoters. Redox thermodynamics of HRP on the 3-MPT films, which is obtained from the temperature dependence of the reduction potential, suggests that the positive shift of redox potentials of HRP at the interface of 3-MPT originates from the solvent reorganization effects and conformational change of the polypeptide chain of HRP. Based on the direct electrochemistry and electrocatalytic ability of HRP, a sensitive third-generation amperometric H₂O₂ biosensor is developed with two linear dependence ranges of 5.0 × 10⁻⁷ to 1.0 × 10⁻⁴ and 1.0 × 10⁻⁴ to 2.0 × 10⁻² mol L⁻¹.     

New hybrid materials incorporating tetrabutyl titanate and tetraethoxysilane with functional SEBS elastomer via the sol-gel process: Synthesis and characterization

New flexible hybrid materials were prepared by incorporating amino-functionalized styrene-ethylene-butylene-styrene block copolymer (SEBS elastomer) with tetrabutyl titanate and tetraethoxysilane. SEBS was modified via nitration and subsequent reduction, giving the product SEBS II bearing amino groups in the hard segments. The trimethoxylsilane functionalization was then achieved by the addition of coupling agent, 3-glycidyloxypropyl trimethoxysilane (GOTMS) in the sol-gel processing. The hydrolytic condensation of these trimethoxylsilane groups on SEBS II with metal alkoxide led to the formation of covalent bonds between the organic polymer chains and the inorganic networks produced in situ to prevent macrophase separation, resulting in better optical properties. Electron micrographs clearly show that the size of dispersed inorganic phase can be reduced by the use of trimethoxyl silane functionalization. The results of dynamic mechanical analysis are also discussed. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 66: 853–860, 1997     

硅氢加成一步合成γ-氨基丙基三甲氧基硅烷

以Speier催化剂为前体、三乙胺为配体,制备了Pt-N(C2H5)3络合物催化剂,研究了该催化剂对3-氨基丙烯与三甲氧基硅烷(TMOS)硅氢加成一步合成γ-氨基丙基三甲氧基硅烷(KH-540)的催化性能。考察了配体种类、反应温度、反应时间、催化剂用量、原料配比和初始压力等因素对硅氢加成反应的影响。实验结果表明,N2保护下,在n(TMOS)∶n(3-氨基丙烯)=1.19∶1(3-氨基丙烯用量为0.064mol)、Pt-N(C2H5)3催化剂用量为1.5μmol、反应初始压力0.9MPa、140℃条件下反应270min时,3-氨基丙烯的转化率为87.9%,KH-540的选择性为81.7%,且无高聚物生成。     

季铵碱树脂催化三甲氧基硅烷制备甲硅烷

为制备高纯度甲硅烷气体,用强碱性季铵碱阴离子交换树脂催化三甲氧基硅烷溶液进行歧化反应.采用脉冲放电氦离子化检测器测试粗甲硅烷气体,用气相色谱-质谱联用仪、感应耦合等离子体质谱仪测试精馏提纯的副产物四甲氧基硅烷.实验结果表明:在30～50℃和0.2～0.3 MPa条件下反应制备的粗甲硅烷气体中,H2、O2、Ar、N2、CH4的质量浓度分别为221.12、1.76、1.61、17.97、0.15μg/L,纯度达到99.9%;副产物四甲氧基硅烷中,金属杂质总质量浓度低于0.15μg/L,可用来制备高纯度硅溶胶;季铵碱催化三甲氧基硅烷歧化反应,反应条件温和,三甲氧基硅烷转化率96%,硅烷产率95%.催化剂易于购买,采用固定床反应器易于控制反应,易于连续加料,此工艺具有工业化生产价值.     

Silicate-based polymer-nanocomposite membranes for polymer electrolyte membrane fuel cells

Proton-exchange membrane fuel cells have emerged as a promising emission free technology to fulfill the existing power requirements of the 21st century. Nafion^® is the most widely accepted and commercialized membrane to date and possesses excellent electrochemical properties below 80 °C, under highly humidified conditions. However, a decrease in the proton conductivity of Nafion^® above 80 °C and lower humidity along with high membrane cost has prompted the development of new membranes and techniques. Addition of inorganic fillers, especially silicate-based nanomaterials, to the polymer membrane was utilized to partially overcome the aforementioned limitations. This is because of the lower cost, easy availability, high hydrophilicity and higher thermal stability of the inorganic silicates. Addition of silicates to the polymer membrane has also improved the mechanical, thermal and barrier properties, along with water uptake of the composite membranes, resulting in superior performance at higher temperature compared to that of the virgin membrane. However, the degrees of dispersion and interaction between the organic polymer and inorganic silicates play vital roles in improving the key properties of the membranes. Hence, different techniques and solvent media were used to improve the degrees of nanofiller dispersion and the physico-chemical properties of the membranes. This review focuses mainly on the techniques of silicate-based nanocomposite fabrication and the resulting impact on the membrane properties.     

烷氧基封端聚硅氧烷及其脱醇型RTV-1硅橡胶的研制

通过α,ω-二羟基聚二甲基硅氧烷(107硅橡胶)与烷氧基硅烷的"封端"反应,制得烷氧基封端聚硅氧烷;再配合纳米碳酸钙、交联剂和钛酸酯催化剂,制得脱醇型单组分室温硫化(RTV-1)硅橡胶。探讨了封端剂类型、纳米碳酸钙和交联剂用量、钛酸酯种类和用量对硅橡胶性能的影响。结果表明,以环己酮肟为催化剂、乙烯基三甲氧基硅烷为封端剂,对黏度20 000 mPa.s的107硅橡胶进行封端制成的烷氧基封端聚硅氧烷(PDMS-4)最适合作脱醇型RTV-1硅橡胶的基胶;当PDMS-4用量为100份、纳米碳酸钙用量为100～130份、交联剂用量为5份、螯合型钛酸酯用量为4.0～5.0份时,脱醇型硅橡胶在生产过程中无"黏度高峰"效应,硫化速度适中,触变性较好,储存期长达1年;邵尔A硬度大于35度,拉伸强度大于2.0 MPa,拉断伸长率大于400%;无需添加增粘剂,对玻璃、铝合金、PC、ABS等材料具有良好的粘接性。