Effect of chemical modification of ion-exchange membrane MA-40 on its electrochemical characteristics

Transport characteristics of commercial heterogeneous anion-exchange membranes MA-40 and MA-41 are studied, together with those of membrane MA-40M fabricated by treating the MA-40 surfaces with a strong polyelectrolyte complex. It is demonstrated that, after modification, the electrical conductivity of MA-40M in an NaOH solution increases. At overlimiting currents, the water dissociation rate on this membrane decreases as compared with the initial membrane. At the same time, no noticeable change in the rate of transport of counter-ions (ions Cl^-) through the membrane at a fixed potential drop is discovered at under-and overlimiting currents. The MA-40M membrane behavior is explained by the conversion of secondary and tertiary functional ammonium groups in the near-surface membrane layers approximately 80 μm thick into quaternary groups during the treatment by the polyelectrolyte.     

金属盐对O2/CO2煤粉混燃钙基脱硫反应的影响

利用添加剂调制改性的方法，考察了以碳酸钠为代表的金属盐对石灰石微观结构的影响，得出调制改性优化了石灰石的物理结构，并在离子比γ为15∶1的加入量效果最佳。在此基础上，借助定硫仪比较了O2-CO2气氛下调制前后石灰石对燃煤SO2释放的影响，并对燃烧产物进行灰熔点分析及灰成分的XRD测试。实验结果表明，在不影响煤粉燃烧结渣特性的前提下，改性后的石灰石可以更有效地抑制SO2的排放，固硫效果在1 000 ℃时达到最佳。     

Surface modification of proteins by covalent binding of acrylic polymers

Surface modification of enzymes for a potential use in therapy was obtained with a new type of tailor-made copolymers ofNacryloylmorpholine andN-acryloxysuccinimide. The first monomer was designed to confer solubility on the polymer, whereas the second was used to give it reactivity toward protein amino groups. The reactivity of polymers of different composition towards amino acid derivatives and model proteins, such as catalase and ribonuclease-A, is described. Water soluble and catalytically active enzyme derivatives were obained using copolymers prepared with a mixture of N-acryloxysuccinimide andn-acryloylmorpholine in a 1:99 molar ratio. At increasing molar ratio (3:97, 10:90) extensive crosslinking between polymer and enzymes takes place, yielding insoluble adducts.     

C_（60）化学修饰的PNVC材料的UV－VIS谱研究

本实验采用金属有机化学方法成功地将富勒烯分子引入到ＰＮＶＣ侧链形成ＣＢＰ（ＣｈａｒｍＢｒａｃｅｌｅｔＰｏｌｙｍｅｒ）型共聚功能材料，研究了其ＵＶ－ＶＩｓ谱行为。结果表明，Ｃ_（６０）或Ｃ_（６０）／Ｃ_（７０）混合物化学修饰的产物其紫外可见谱明显向长波方向移动，谱峰范围由２８０ｎｍ扩展至８７０ｎｍ。Ｃ_（６０）含量增加，红移程度增大，在可见区域的吸收程度亦增加。产物主要存在５个特征峰，分别位于２１５ｎｍ、２６５ｎｍ、２９８ｎｍ、３３５ｎｍ、３４５ｎｍ处，其中２１５ｎｍ峰为Ｃ_（６０）仅存的特征峰。最后讨论了不同合成条件与产物硝化处理对其ＵＶ－ＶＩＳ谱行为的影响。     

HZSM－20沸石分子筛的水蒸汽改性

ＨＺＳＭ－２０沸石分子筛的水蒸汽改性项寿鹤，任大立，王敬中，李赫晅（南开大学化学系，天津３０００７１）关键词ＨＺＳＭ－２０沸石，水蒸汽处理，改性ＺＳＭ－２０沸石是一种具有大孔和开放结构的分子筛［１］，其结构与八面沸石（如Ｙ型沸石）类似，但其硅铝比较高...     

低分子量聚乙烯双单体非均相共接枝

在非均相体系中采用甲苯－水共沸条件下由自由基引发剂引发，低分子量的聚乙烯与丙烯酸和甲基丙烯酸甲酯进行双单体共接枝反应，从而对非极性聚乙烯进行化学改性，探索一条新型聚乙烯接枝改性的途径，考察了反应温度、时间、物料比、引发剂用量等诸多因素对接枝效果的影响。     

Modification of HPTLC-plates by in situ chemical bonding with non-polar and polar organosilanes

A method has been developed for the preparation of modified silica plates for high performance thin-layer chromatography (HPTLC). Some typical organosilanes were thus allowed to react in situ with the silica of Merck HPTLC-plates. This method was found to be highly reproducible, simple and cheap. Non-polar plates were prepared and compared with commercial plates from Merck, Whatman and Macherey-Nagel. Modification with cyanodecyltrichlorosilane resulted in plates that showed good coverage, efficiency and low residual silica activity. Silica modified with a multifunctional silane has different properties in different organic solvents. It will appear to be non-polar in a polar solvent and vice versa. New advantageous separation systems are thus made feasible by the presence of cyano groups on the plate. The utility of modified thin-layer plates is demonstrated by the separation of some homologues of p-hydroxybenzoic acid esters and of some polycyclic aromatic hydrocarbons.     

Electroless preparation and electrochemical behavior of a platinum-doped nickel hexacyanoferrate film–zinc modified electrode: catalytic ability of the electrode for electrooxidation of methanol

The use of a zinc substrate as an electrode and the modification of its surface by means of a thin film of platinum-doped nickel hexacyanoferrate (Pt-NiHCF) were developed. The modification conditions of the zinc surface including the electroless deposition of metallic nickel on the electrode surface from NiCl₂ solution, chemical derivatization of the deposited nickel to the NiHCF film in 0.5 M K₃[Fe(CN)₆] solution, and electrochemical penetration of metallic platinum into the modified film are described. The modified zinc electrodes prepared under optimum conditions show a well-defined redox couple due to the [Ni^IIFe^III/II(CN)₆]^1–/2– system. The effects of pH, the alkali metal cation, and the anion of the supporting electrolyte on the electrochemical characteristics of the modified electrode were studied in detail. The diffusion coefficients of hydrated alkali metal cations in the film (D), the transfer coefficient (), and the transfer rate constant for the electron (k_s) were calculated in the presence of some alkali metal cations. The electrocatalytic activity of the modified electrode for methanol oxidation was demonstrated. The stability of the modified electrode under various experimental conditions was investigated.     

Complexation of an acrylic resin by tertiary amines: synthesis and characterisation of new binders for antifouling paints

Antifouling coatings are the most reliable way to prevent biofouling of immersed surfaces. As concerning the high toxicity of organotin paints, the tendency is the development of coatings, which do not present environmental risks. In this work, we prepare binders from modification of acrylic copolymers containing free carboxylic acid groups. Biocides chosen are tertiary ammonium salts; alkyl chain substituents with different length are considered. The chemical modifications of resins are carried out via a single step reaction. Modification extents are monitored through proton nuclear magnetic resonance and thermogravimetric analysis and the modified resins are characterised by Fourier transform infrared spectroscopy. The glass transition temperature of the acrylate systems is assessed by dynamical mechanical analysis (pin point method) and compared with data obtained by differential scanning calorimetry. The erosion and antifouling properties of the binders are followed during an exposure to marine environment by a visual observation.     

尼龙1010结构与性能研究进展（下）：结晶,熔融,性质,改性

本文介绍了尼龙１０１０的结晶过程与动力学、晶体的熔融与转化；并论述了其稀溶液、热降解与动态力学性质及共聚、共混、填充、增强、交联改性方面的研究进展。