表面活性剂对镧、钇-8-羟基喹啉-5-磺酸萤光反应的敏化作用

本文讨论了阳离子表面活性剂——溴化十六烷基三甲基铵(CTMAB)对萤光反应敏化作用的机理;提出了镧、钇的萤光分析方法,并确定了萤光反应的最佳条件。镧、钇的三元络合物与其二元络合物相比,萤光强度分别增强了四倍和十倍。表面活性剂的引入也大大地增加了方法的选择性。在此基础上,设计了先测定钇含量,然后用简单的作图法测定镧含量的镧、钇联合测定法。用本法测定了混合稀土样中谰、钇的含量,方法简便,结果令人满意。     

水杨基萤光酮-N-氯化十六烷基吡啶双波长光度法测定钢铁中微量铬

近年来,利用阳离子表面活性剂增敏光度法测定Cr(Ⅵ),见报道的有。其中用高灵敏显色剂萤光酮衍生物的则有,Cr(Ⅵ)-邻羟基氢醌酞-CTMAB(ε=1.64×10~5),Cr(Ⅵ)-二溴苯基萤光酮-CPB(ε_(580)=1.44×10~5)和Cr(Ⅵ)-水杨基萤光酮-CTMAB(ε_(585)=1.2×10~5),前者选择性不理想。本文提出用水杨基萤光酮-CPC双波长光度法测定Cr(Ⅵ),ε_(580)=2.6×10~5,为目前水相光度测定Cr(Ⅵ)的最高值,用于钢铁中微量铬的测定,结果满意。     

水杨基萤光酮-溴化十六烷基三甲基铵分光光度法测定金属材料中的微量锡

在阳离子表面活性剂存在下,利用邻苯二酚紫,苯基萤光酮,茜素紫等试剂测定锡的方法具有较高的灵敏度。例如,苯基萤光酮-溴化十六烷基三甲基铵法的摩尔吸光系数可达到1.34×10~5。本文研究用水杨基萤光酮(SAF)-溴化十六烷基三甲基铵(CTMAB)分光光度法测定微量锡。本法在灵敏度和选择性方面比上述各法均有较大的提高。方法的表观摩尔吸光系数。ε=1.79×10~5(在751型分光光度计上测得)。由于显色反应的酸度较高,因此,除钛、钼、钨、锑     

铽(Ⅲ)萤光探针对核酸单链结构的检测

在室温和中性水溶液中,核酸及其天然碱基的萤光量子产率非常低,使用一般仪器不能测出它们的萤光。因此,进行核酸的萤光分析必须借助各种萤光探针。例如常用的菲啶溴红、原黄素.吖啶橙和光神霉素等有机萤光探针,在核酸分子结构的研究中都提供了许多有用的信息。最近发现稀土元素铽的阳离子     

锡(Ⅳ)和二溴苯基萤光酮显色反应的研究及其分析应用

分光光度测定低含量锡常采用苯基萤光酮、邻苯二酚紫、茜素紫法。其中使用苯基萤光酮较为广泛,摩尔吸光系数最高达1.3×10~5。最近发表的水杨基萤光酮对锡(Ⅳ)的显色反应灵敏度可达1.79×10~5。许多显色剂的溴化物与其母体相比,在与金属离子反应时其灵敏度有显著提高,选择性     

2,5-二取代噁唑的研究(Ⅲ)——2-联苯基-5-苯基噁唑和其5-对位取代苯基衍生物的合成

合成了2-联苯基-5-苯基噁唑和13种5-对位取代苯基衍生物,测定了它们的熔点,红外紫外吸收光谱,萤光发射光谱,萤光量子产率(φ_i)和激光转换效率(η_i)。     

希土元素的定量分析法(下)

(3)萤光分析萤光分析法是另外一种利用发射光谱的分析方法。诚然,它在希土分析方面的应用是受到限制的。它是由于强烈的电磁辐射(如紫外线)所激发而形成的可见发射光谱,紫外线的波长位于210—230mμ范围内时具有最大的效率。从盛有被研究溶液的器皿中摄取萤光光谱是用摄谱仪。摄谱仪的位置和用紫外线照射器皿的方向成垂直萤光光谱大约与电弧或火花激发所产生的线状光谱是同时发现的。但它们应用于分析工作到现在为止仍未     

2,4-二氯苯基萤光酮-溴化十六烷基三甲基铵分光光度测定钽

2,3,7-三羟基-9取代基萤光酮是胶束增敏分光光度法中一类高灵敏的显色剂,已有用水杨基萤光酮,二溴苯基萤光酮测定钽的报导,但直接测定均只是铌钽合量。我们用自行合成的九种不同9取代三羟基萤光酮,对铌和钽的测定性能作了系统的比较,从中筛选出灵敏度高、选择性好的2,4-二氯萤光酮,推荐作为测钽的优良试剂。因在2～3.6N高酸度下     

铬(Ⅵ)与9-取代-2,3,7-三羟基萤光酮氧化显色反应的研究及其在金属材料分析中的应用

在盐酸与磷酸的混合酸介质中,铬(Ⅵ)与9-取代-2,3,7-三羟基萤光酮(水杨基萤光酮、邻硝基苯基萤光酮以及邻氯苯基萤光酮)反应产生橙黄色氧化产物。其吸收峰位于492-497nm。反应具有很高的选择性,除氧化性物质以外,其他各种金属元素均不干扰铬(Ⅵ)的测定。拟定了用邻硝基苯基萤光酮分光光度法测定各种金属材料中铬的新方法。     

镝钬混合物中微量铽的萤光分光光度测定

在铽镝钬分离工艺中,要求控制镝(80—90%)钬(10—20%)混合物中铽<0.03%(均以氧化物计),而发射光谱法测定镝基体中铽的下限为0.07%。H.C.Полуэктов曾研究用钛铁试剂萤光光度法测定铽,我们在前人工作的基础上,进一步进行了试验。表明,铽-钛铁试剂络合物的萤光具有较高的灵敏度,但共存的镝钬及其他稀土元素和常见元素的含量变化,对铽的萤光强度有一定影响。为消除基体组份变化及可能存在的其他离子影响,需采用标准加入法。铽络合物在24小时内萤光强度不变,但其萤光强度受紫外光     

Cope elimination and complexation of poly(dimethylaminoethyl methacrylate N-oxide)

Poly(dimethylaminoethyl methacrylate N-oxide) (poly(DMAEMNO)) was prepared by oxidation of poly(dimethylaminoethyl methacrylate) with hydrogen peroxide in methanol. From thermogravimetric and IR spectroscopic investigations Cope elimination of amine oxide group in poly(DMAENO) was found to occur at 120–150°C. The postpolymerization of partially pyrolyzed polymer carrying vinyl ester group as pendant was performed with azobisisobutyronitrile at 60°C in methanol to give cross-linked polymer that was found to form hydrogel. Poly(DMAEMNO) gave metal–polymer complexes with CuCl₂, ZnCl₂, and CoCl₂. Cobalt–polymer complex had a constitution of 1:2 of metal ion to amine oxide group, while copper– and zinc–polymer complexes seemed to have structures of 1:1 and 1:2 of metal ion to amine oxide group. Furthermore, polymer complexes of poly(DMAEMNO) with poly(methacrylic acid) and poly(acrylic acid) were found to be formed by mixing aqueous solutions of both polymers and also by radical polymerization of the acid monomers in the presence of poly(DMAEMNO). From elemental analysis, thermogravimetric investigation, and measurement of turbidity it was concluded that the resulting polymer–polymer complexes contained more than one acid monomer unit per one N-oxide unit.     

Application of inverse gas chromatography in the surface characterization of diethanol amine modified polystyrene based polymer

In the present work, diethanol amine modified polystyrene based polymer (PVBC-Diethanol amine) was synthesized and characterized, then surface properties of the polymer were examined by inverse gas chromatography method at infinite dilution. The retention diagrams obtained based on the interaction of polar and nonpolar probes with the polymer were drawn over a temperature range from 30 to 55 °C. Through the diagrams, the dispersive component of the surface free energy, g _S ^D of the polymer surface, and the specific enthalpy of adsorption, DH _A ^S , of probes on the polymer were also calculated. Lewis acid, K _A , and Lewis base, K _D , parameters of PVBC-Diethanol amine surface were determined. The values of K _A and K _D indicated that PVBC-Diethanol amine surface exhibited a basic behavior.     

STUDIES ON THE ORGANIC PEROXIDE-DITERTIARY AMINE INITIATION SYSTEMS

Radical polperization of methyl methacrylate (MMA) initiated with organic peroxide-ditertiaryamine binary systems was studied. Benzoyl peroxide (BPO), lauroyl peroxide (LPO), t-butyl hydro-peroxide (TBH), and t-butyl peroxybenzoate (TBPB) were used as organic peroxide components,aromatic ditertiay amine 4, 4′-tetramethyldiaminodiphenylmethane (TMDAPM) an d aliphatic di-tertiary amine tetramethylethylenediamine (TMEDA) were used as amine components. The polymeri-zation rate R_P, the overall activation energy of polymerization E_a, the rate equation of MMA poly-merization, and the end group of polymer formed were determined.     

Substrate-Independent Stable and Adherent Reactive Surface Coatings and their Conversion with Amines

Summary: To create stable, adherent and reactive surface coatings, a hybrid polymer composed of poly(methylsilsesquioxane) (PMSSQ) and poly(pentafluorophenyl acrylate) PFPA with a M_n of 32000 g/mol was prepared by a RAFT polymerization procedure. These hybrid polymer has been used for coating experiments. The PFPA part enabled a variable functionalization of the coating afterwards. The stability on various substrates (e.g. glass, PMMA, steel) was tested in an ISO tape test. These reactive surface coatings were modified using different amines, such as amino-terminated PEG, dodecyl amine and N-isopropyl amine. The conversion was analyzed by FT-IR and contact angle measurements.     

Amine‐Appended Hierarchical Ca‐A Zeolite for Enhancing CO2/CH4 Selectivity of Mixed‐Matrix Membranes

An amine‐appended hierarchical Ca‐A zeolite that can selectively capture CO₂ was synthesized and incorporated into inexpensive membrane polymers, in particular polyethylene oxide and Matrimid, to design mixed‐matrix membranes with high CO₂/CH₄ selectivities. Binary mixture permeation testing reveals that amine‐appended mesoporous Ca‐A is highly effective in improving CO₂/CH₄ selectivity of polymeric membranes. In particular, the CO₂/CH₄ selectivity of the polyethylene oxide membrane increases from 15 to 23 by incorporating 20 wt % amine‐appended Ca‐A zeolite. Furthermore, the formation of filler/polymer interfacial defects, which is typically found in glassy polymer‐zeolite pairs, is inhibited owing to the interaction between the amine groups on the external surface of zeolites and polymer chains. Our results suggest that the amine‐appended hierarchial Ca‐A, which was utilized in membrane fabrication for the first time, is a good filler material for fabricating a CO₂‐selective mixed‐matrix membrane with defect‐free morphology.     

Area Selective Polymer Brush Deposition

Polymer brush films with chemical functionality to attach to site specific substrate areas are introduced for area selective deposition (ASD) application. It is demonstrated that polymer brushes with chemically defined end sites can be selectively bound to copper‐specific regions of patterned copper/silica (Cu/SiO₂) substrates. The process described overcomes various limitations of currently used technology including cost, complexity, and throughput, with potential implications for future electronic devices and nanomanufacturing. A comparative study of amine‐terminated polystyrene and amine‐terminated poly‐2‐vinyl pyridine polymer brushes (i.e., PS‐NH₂ and P2VP‐NH₂) with similar molecular weights display contrasting behavior on patterned Cu/SiO₂ line features. Further, a thiol terminated poly‐2‐vinyl pyridine polymer brush (i.e., P2VP‐SH) is investigated as a direct spin‐on process to fabricate a metal oxide layer atop Cu areas only. The results presented here detail a novel methodology and open a new exciting process for ASD practices that can facilitate the precise deposition of dense metal, semiconductor, or dielectric films. We also discuss the applicability of polymer brushes to ASD uses going forward.     

Rhodium amino complexes [Rh(COD)(Amine)2]PF6 immobilized on poly(4-vinylpyridine) as catalysts in the water gas shift reaction

Catalysts for the water gas shift reaction prepared from Rh(COD)(amine)₂ PF₆ (COD=1,5-cyclooctadiene, amine=4-picoline, 3-picoline, 2-picoline, pyridine, 3,5-lutidine or 2,6-lutidine) immobilized on poly(4-vinylpyridine) in contact with 80% aqueoux 2-ethoxyethanol for 1×10⁻⁴ mol Rh/0.5 g of polymer, P(CO)=0.9 atm at 100 °C, are described. The role of the coordinated amine effect on the catalytic activity was investigated.     

SYNTHESIS OF CONDENSATION POLYMERS OF SALICYLIC ACID, FORMALDEHYDE AND ALKYL PRIMARY AMINES AND ITS APPLICATION AS A CATALYST FOR THE HYDROLYSIS OF p-NITROPHENYL ACETATE (PNPA) IN AQUEOUS SOLUTION

As a model of serine hydrolase, the condensation polymers of salicylic acid, formaldehyde and methyl amine, n-propyl amine, n-hexyl amine or n-lauryl amine were prepared by polycondensation catalyzed by sulfuric acid. It was confirmed by potentiometric titration and infrared spectrum that the polymers containing tertiary amino group possess the structure which resembles the internal salt of amino acid in weak basic and weak acidic solution:     

Incorporation of a photochromic hinge in a rodlike polypeptide and its influence on dielectric and optical properties

A hinged, photoresponsive polypeptide (PAzP) was prepared and the effect of the photochromic hinge on the dielectric and photoisomerization behavior of the polymer in solution was probed. Polymerization of N‐carboxyanhydride of γ‐benzyl‐L ‐glutamate was carried out with two different bifunctional photochromic amine initiators: di[(mercaptoethylamine)‐methylpropanamide]azobenzene (DMMPAB) and diaminoazobenzene (DAAB). Careful structural comparison of the polymers revealed that the basicity of the initiator plays a key role in determining the shape and structure of the polymer. Specifically, the use of a novel initiator DMMPAB prepared by the addition of flexible aliphatic amine substituents onto DAAB resulted in a hinged polymer (PAzP1), in which a single photochromic hinge was located within the polymer chain (M_w ～ 36 kDa). In contrast, direct initiation with DAAB resulted in a polymer (PAzP2) in which the photochromic moiety was preferentially near the terminus of the polymer chain (M_w ～ 21 kDa) and the polymer possessed a significant degree of asymmetry. Dielectric spectroscopy revealed that, in spite of a higher molecular weight, PAzP1 had a lower rotational relaxation time (2.72 μs) in solution than that of PAzP2 (4.41 μs). The residual dipole moment for the hinged PAzP1 was also smaller than that observed for PAzP2. The hinged polypeptide PAzP1 prepared from DMMPAB showed uniform photoisomerization between cis and trans states. However, the presence of flexible aliphatic amine substituents on DMMPAB caused the rate of isomerization of PAzP1 to be similar to the initiator DMMPAB. Optical characterization revealed that heterogeneity in the structure of PAzP2 was manifested as nonuniform rates of photoisomerization and thermal relaxation. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 2759–2773, 2001     

Preparation and Characterization of In-Situ Polymerized Nanocomposites Based on Polyaniline in Presence of MWCNTs

Summary: Polyaniline (PANI) composites were prepared with both unmodified and amine modified MWCNTs with and without BaTiO₃ through in-situ oxidative polymerization. Uniform coating of PANI on the MWCNTs and BaTiO₃ surfaces was found which was evident from the Field Emission Scanning Electron Microscopic (FESEM) and High Resolution Transmission Electron Microscopic (HRTEM) images. The structure of pure and amine modified MWCNTs was identified by Fourier Transform Infrared Spectroscopy (FTIR). The thermal stability of the amine modified composite with BaTiO₃ is higher than that of the unmodified composite because of the better affinity between modified MWCNTs and polymer matrix and due to the higher stability of barium titanate itself. The capacitance of amine modified MWCNTs and BaTiO₃ composites was less than that of the pure MWCNTs composites but the thermal stability increased in amine modified MWCNTs and BaTiO₃ composites with respect to the pure MWCNTs composites. The maximum capacitance and energy density values were found in MWCNT/PANI composites which were equal to 523.20 F/g and 142.83 Wh/kg respectively at a scan rate of 10mv/s. Maximum power density was found to be 5147.70 W/kg in the same composite at a scan rate of 200 mv/s.