水中痕量钼(Ⅵ)的4-(2-吡啶偶氮)-间苯二酚螯合活性炭吸附富集分光光度法测定

提出了一种简单快速预富集水中痕量钼（Ⅵ）的新方法，方法的机理在于4－（2－吡啶偶氮）－间苯二酚（PAR）与钼（Ⅵ）螯合后被活性炭中附，然后用NaOH解吸下来，再用水杨基荧光酮与钼（Ⅵ）显色，分光光度法测定钼（Ⅵ）的含量；详细研究了影响Mo-PAR螯合物定量吸附于活性炭上的各种参数，找出了最佳吸附－解吸条件，包括吸附酸度、PAR用量、吸附时间、解吸酸度等；该法的主要优点是操作简单、快速，干扰小，避免了常规方法中用浓硝酸消化活性炭费时和污染大的解吸方法，该法已用于测定水中痕量钼（Ⅵ），加标回收率达到94％－97％。     

在聚乙烯吡咯啉酮-盐-水的液-固萃取体系中溴络阴离子的萃取行为

本文研究了在聚乙烯吡咯啉酮（PVP）－盐－水的液－固萃取体系中，Au（Ⅲ）、Bi（Ⅲ）、Zn（Ⅱ）和Fe（Ⅲ）与Br形成的络阴离子，在两相间的分配行为。在硫酸和盐酸介质中，Au（Ⅲ）有很高的萃取率，Fe（Ⅲ）的萃取率很低，而Bi（Ⅲ）和Zn（Ⅱ）的萃取率则受溶液的酸度、NH；Br的浓度及溶液介质的影响。在硫酸介质中，通过控制溶液的酸度和NH4Br的浓度，实现了Bi（Ⅲ）－Fe（Ⅲ）、Au（Ⅲ）－Zn（Ⅱ）及Au（Ⅲ）－Fe（Ⅲ）等的定量萃取分离与测定。     

TritonX-100-盐-水液-固萃取体系分离Co,Cd,Zn

在含有一定浓度硫酸铵的条件下，ＴｒｉｔｏｎＸ－１００水溶液能形成盐水相与聚合物固相。本实验研究了Ｃｏ（Ⅱ）、Ｃｄ（Ⅱ）、Ｚｎ（Ⅱ）、Ｃｕ（Ⅱ）、Ｆｅ（Ⅲ）与４－（２－吡啶偶氮）间苯二酚（ＰＡＲ）形成的配合物在ＴｒｉｔｏｎＸ－１００盐水萃取体系液固两相中的分配行为。主要探讨萃取酸度，萃取剂用量和硫酸铵浓度等条件对金属离子萃取率的影响。用控制酸度的方法实现了Ｃｏ（Ⅱ）与Ｃｄ（Ⅱ），Ｃｏ（Ⅱ）与Ｚｎ（Ⅱ）的定量分离。每组金属离子浓度在１∶１０００倍情况下分离互不干扰，结果满意。该法可用于样品的提纯与分离。     

2,4,5-涕丙酸的NMR手性分离条件

以1，2－二苯基二氨基乙烷（简称DPEDA，化合物1）的（1R，2R）体（简称（R）－1）为手性溶剂（CSA），解决了外消旋2，4，5－涕丙酸（化合物2）在氯仿溶剂中溶解性不良的问题，并且化合物2的^1H谱获得了出色的手性分离效果；通过研究包括温度、浓度、底物与CSA的摩尔比、CSA结构等影响化学位移不等价的因素得出结论，对于手性中心CH，在化合物2与（R）－1的摩尔比为2：1时，提高底物浓度和降低测试温度有利于增加手性分离度；而对于与手性中心相连的CH3，增大（R）－1的比例，减小底物浓度，提高测试温度，有利于增大△δH；化合物1的（1S，2S）体（简称（S）－1）与（R）－1具有相同的手性分离作用；另外还对各影响因素的作用机理进行了探讨。     

用PAR作显色剂光度法研究铼（Ⅶ）在双水相萃取体系（聚乙二醇2000-硫酸铵）中的分配行为

以4-（2-吡啶偶氮）-间苯二酚（PAR）为显色剂,用光度法研究了铼（Ⅶ）在聚乙二醇2000（PEG）-硫酸铵双水相萃取体系中的分配行为。萃取系在有一定量铼标准溶液存在,且含有300g·L~（-1）聚乙二醇2000溶液及300g·L~（-1）硫酸铵溶液各3mL及1g·L~（-1）PAR溶液1mL,并用磷酸盐缓冲溶液控制...     

聚谷氨酸苄酯-聚乙二醇嵌段共聚物的合成和表征

通过嵌段共聚技术,合成了聚γ－苄基L－谷氨酸（PBLG）作为疏水性链段－聚乙二醇（PEG）作为亲水性链段的嵌段共聚物。用对甲苯磺酸酯化－氨水皂化法合成带有端氨基的聚乙二醇（AT－PEG）,光气－甲苯液相法制备谷氨酸苄酯－N－羟酸酐（BLG－NCA）。用AT－PEG引发BLG－NCA聚合制备PBLG－PEG或PBLG－PEG－PBLG,通过不同的单体、引发剂浓度比调节聚合物分子量。用GPC、^1HNMR、IR对聚合物的结构进行了表征。结果表明,带有端氨基的聚乙二醇确实能引发BLG－NCA生成PBLG和PEG的嵌段共聚物,产物中几乎没有残存的PEG,共聚物的分子量可控。     

聚醚酮醚酮酮/含萘环聚醚酮醚酮酮无规共聚物的合成与性能

在无水AlCl3及N－甲基吡咯烷酮（NMP）存在下，以4,4′-二（α－萘氧基）二苯酮（DNBP）作为第三单体，将其与4，4′－二苯氧基二苯酮（DPBP）和对苯二甲酰氯（TPC）在1，2－二氯乙烷（DCE）中进行低温溶液共缩聚反应，合成了一系列聚醚酮醚酮酮／含萘环聚醚酮酮醚酮酮无规共聚物，用IR、DSC、TG及WAXD等方法对其结构和性能进行了表征与测试。研究结果表明共聚物的玻璃化转变温度（Tg)要比纯PEKEKK的高，而其熔融温度（Tm)和结晶度（Xc)则随共聚物中含萘环PEKEKK结构单元含量的增加而逐渐降低。共聚物具有优异的耐热性能及抗腐蚀性能。     

酵母核糖核酸的UV-Vis光谱探针反应的机理研究

采用UV－Vis分光光度法，研究在pH7－8的缓冲溶液中，酵母核糖核酸（RNA）与3－氨基－6－二甲氨基－2－甲基吩嗪盐酸盐（ZR）相互作用；反应生成红色配合物，该配合物的最大吸收波长为540nm；反应前后的吸收光谱变化明显，配合物的吸收峰与试剂本身比较红移90nm；研究了体系的酸度、温度、时间等基本反应条件以及不同类型的离子对体系的影响，发现离子强度的改变对体系的吸光度有明显的影响。     

N，N－二乙基甲酰胺代甲基膦酸二正己酯萃取金（Ⅲ）

本文报道Ｎ，Ｎ－二乙基甲酰胺代甲基膦酸二正己酯（简称Ｅ）萃取金（Ⅱ）的各种参数，如分配比、振荡时间、相比、水相酸度及酰的种类，以及其它离子对萃取金（Ⅲ）分配比的影响。并求得了达到平衡时化合物Ｅ萃取金反应的焓变（ＯＨ）和熵变（ＯＳ）。     

铟（Ⅲ）－PMBP－Ferron极谱络合吸附波研究

在ＨＣｌ－ＮａＡｃ介质（ｐＨ２．５）中，可获得灵敏的Ｉｎ（Ⅲ）－ＰＭＢＰ－Ｆｅｒｒｏｎ极谱络合吸附波，峰电位在－０．６５Ｖ处（ｖｓ·ＳＣＥ），检出限为０．０４ｎｇ／ｍＬＩｎ。峰电流与铟浓度在０．０８～２００ｎｇ／ｍＬ范围内呈线性关系。本法测定工业废水中的痕量铟，结果满意。本文还研究了极谱波的性质和机理。     

用简易凝胶渗透色谱柱研究氯醇橡胶

用简易GPC柱研究了三种类型氯醇弹性体的分子量分布。装柱填料是多孔硅胶球。理论塔板数2000块/米以上。用三异丁基铝-磷酸-水-二甲基苯胺催化剂制得的均聚氯醇胶比用三异丁基铝-磷酸-苯并噻唑亚磺酰胺所得氯醇胶分子量分布宽,宽度指数在3—6之间。均聚氯醇胶在素炼过程中,分子量分布变窄,分子量变低。转化率增加,单体浓度增加或温度降低使分布变宽。催化剂中的二甲基苯胺对三异丁基铝克分子比影响二元共聚胶的分布宽度。     

双水相手性萃取拆分扁桃酸外消旋体

研究了扁桃酸(MA)对映体在含β-环糊精(β-CD)手性选择剂的聚乙二醇(PEG)/(NH_4)_2SO_4双水相体系中的萃取分配行为.考察了pH、PEG和(NH_4)_2SO_4的质量分数、β-CD的浓度、MA的浓度与萃取温度等因素对拆分效果的影响.实验结果表明:双水相手性萃取具有很强的手性分离能力,β-CD对L-MA对映体的识别能力大于对D-MA对映体的识别能力;当温度为30℃、pH=1.0、PEG2000质量分数为30%、(NH_4)_2SO_4质量分数为20%、β-CD的浓度为0.008 mol/L、扁桃酸的浓度为0.05 mol/L时,分离因子(α)达到2.46,上、下相对映体过剩值(e.e.%)分别为42.13%和40.43%.     

STUDIES ON ULTRASONIC ABSORPTION AND VISCO-RELAXATION OF POLY (ETHYLENE GLYCOL) AQUEOUS SOLUTIONS

Ultrasonic absorption and velocity measurements were made on aqueous solutions of poly (ethylene glycol)(PEG)of different molecular weights and concentrations, using a pulse sender-receiver ultrasonic generator, Measurements were obtained at a frequency of 2MHz. , and a temperature of 293 K. The results show a linear increase of the Values of velocity, density and viscosity with increase of molecu lar weight and concentration of PEG. On the contrary, the attenuation values decreased with increase of molecular weight and concentration of PEG. A mathematical equation correlating relaxation amplitude and molecular weight of the polymer is suggested. This was applied to calculate the molecular weights of unknown samples of PEG from their measured relaxation amplitude. The results obtained were in good agreement with those obtained from osmometry.     

Thermo-Responsive Hydrogels Based on Branched Poly(L-lactide)-poly(ethylene glycol) Copolymers

Summary: Branched poly(L -lactide)-poly(ethylene glycol) (PLLA-PEG) block copolymers were synthesized from trifunctional PLLA and amine functionalized methoxy poly(ethylene glycol)s. The copolymers in water formed hydrogels that showed thermo-responsive behavior. The hydrogels underwent a gel to sol transition with increasing temperature as determined with the vial tilting method and oscillatory rheology. For all copolymers, the transition temperature increased with increasing copolymer concentration. The transition temperature of corresponding branched copolymers also increased with increasing PEG molecular weight, and surprisingly decreased with increasing molecular weight of the PLLA branches. In general, the gel-sol transition is explained by disruption of micellar or aggregate interactions because of partial dehydration and shrinkage of the PEG chains. An increase in the molecular weight of the PLLA branches led to the formation of micelles and aggregates as observed with DLS at low concentrations. It is speculated that the non-uniform size distribution and possible crystallization of longer PLLA blocks may have a negative effect on the formation of micellar packing upon gelation, allowing the disruption of micellar or aggregate interactions to occur at lower temperatures. The transition temperature of the gels could be tuned closely to body temperature by varying the concentration of the solution or the molecular weight of the PEG block and the PLLA blocks, which implies that these polymers may be used as injectable systems for in-situ gel formation.     

Polyethylene Glycol for LiFePO<Subscript>4</Subscript>/C Composites Preparation: Large or Small Molecular Weight

Olivine LiFePO₄ is challenged by its poor electronic and ionic conductivities for lithium-ion batteries. Polyethylene glycol (PEG) has been applied for LiFePO₄ preparation by different research groups, but there is no consensus on the influence of the mean molecular weight of PEG on the structure and electrochemical performances of LiFePO₄/C composites. In this work, LiFePO₄/C composites were prepared by using micronsized FePO₄·2H₂O powder as starting material, PEG (mean molecular weight of 200, 400, 4000 or 10000) and citric acid as complex carbon source. The structure and electrochemical performances of LiFePO₄/C composites would be decided considerably by the mean molecular weight of PEG, and the sample using PEG200 exhibited the least inter-particle agglomeration, the smallest charge transfer resistance and the highest discharge capacity. A probable growth mechanism is also proposed based on SEM images and electrochemical results: with the assistance of citric acid, PEG molecule with small molecular weight tends to cover one or only a few micron-sized FePO₄·2H₂O particles, significantly suppress the agglomeration of primary LiFePO₄ particles and thus result in uniform particle-size distribution and carbon coating.     

Self-diffusion in poly(N -vinyl pyrrolidone) – poly(ethylene glycol) systems

 We have applied the PFG NMR technique to investigate the translational mobility in the PVP-PEG system as a function of composition and temperature at the stages of PVP-PEG complex formation, its swelling, and dissolution in excess of liquid PEG. It has been found that the variations of the spin-echo attenuation with PEG content, water amount, and temperature reflect the different stages. The first two stages are characterized by a distribution of the self-diffusion coefficients of PEG involved in the network. The dissolution shows two diffusion coefficients; the fast one is attributed to PEG molecules, the slow one to the associates of PEG and PVP. The temperature dependencies can be described by an Arrhenius law with an activation energy depending on the composition of the blend. The concentration dependence of the PEG self-diffusion coefficients in the blend occurred to be independent of the molecular weight of PVP. The results are discussed in terms of the Mackie-Meares model. Received: 23 August 2000 Accepted: 19 October 2000     

一种新的PEG凝聚人血清白蛋白液相压电免疫传感器

以ＰＥＧ为乳剂，建立了一种基于ＰＥＧ凝集的液相压电免疫分析法，并用于人血清白蛋白（Ａｌｂ）的测定。详细考察了ＰＥＧ浓度，抗体稀释度、ＰＥＧ分子量及反应温度等因素对频移的影响，采用终点法和初始速率法测得Ａｌｂ线性范围分别为４７．８３－１０３．１ｍｇ／Ｌ和４０．６２－１０１．２ｍｇ／Ｌ。对７个血清样本的分析，其结果与双缩脲法基本一致。用一简单的方法合晶振再生后可获得重视的结果。     

Fabrication and photoelectrochemical properties of porous ZnWO4 film

Porous ZnWO₄ films have been fabricated on Indium-tin oxide (ITO) glass and its photoelectrochemical properties and high photocatalytic activities towards degradation of rhodamine B (RhB) has been investigated. Using amorphous heteronuclear complex as precursor and with the addition of polyethylene glycol (PEG, molecular weight=400), the porous ZnWO₄ films have been achieved at the temperature of 500 °C via dip-coating method. It is composed of approximately 70 nm-sized particles and exhibits substantial porosity. The textures and porosity of ZnWO₄ films are dependent on preparation factors, such as the ratio of precursor/PEG and the annealing conditions. The formation mechanism of porous ZnWO₄ films was proposed. The porous ZnWO₄ films exhibited high photocatalytic activities towards degrading RhB. The top of valence band and the bottom of the conduction band was estimated to be −0.56 and 3.45 eV (vs. saturated calomel electrode (SCE)), respectively.     

Structural and dynamical aspects of PEG/LiClO4 in solvent mixtures via NMR spectroscopy

Motivated by the potential usefulness of polyethylene glycol (PEG)/Li⁺ salt mixtures in several industrial applications, we investigated the structure and dynamics of PEG/LiClO₄ mixtures in D₂O and its mixtures with CD₃CN and DMSO-d₆, in a series of PEG-based polymers with a wide variation in their molecular weights. ¹H NMR chemical shifts, T₁/T₂ relaxation rates, pulsed-field gradient NMR diffusion experiments, and 2D HOESY NMR studies have been performed to understand the structural and dynamical aspects of these mixtures. Increasing the temperature of the medium results in a significant perturbation in the H-bonded structure of PEG in its PEG/LiClO₄/D₂O mixtures as observed from the increase in chemical shifts. On the other hand, the addition of molecular cosolvents has a negligible effect. The hydrodynamic structure of PEG shows a pronounced variation at low temperature with increasing molecular weight, which, however, disappears at higher temperatures. Increasing the temperature leads to a decrease in the hydrodynamic structure of PEG, which can be explained on the basis of solvation–desolvation phenomena. The 2D HOESY NMR spectra reveal a new finding of Li⁺-water binding in the PEG/LiClO₄/D₂O mixtures with the addition of molecular solvents, suggesting that the Li⁺ cation diffuses freely in the D₂O mixtures of polymers as compared with the polymer mixtures with DMSO or CD₃CN.     

Sol–gel silica antireflective coating with enhanced abrasion-resistance using polypropylene glycol as porogen

Silica antireflective (AR) coatings with high transmittance and enhanced abrasion-resistance were synthesized by sol–gel process using polypropylene glycol (PPG) as porogen. The effects of molecular weight of PPG and weight ratio of PPG to SiO₂ on the refractive index and abrasion-resistance of the coating were systematically studied and compared with those of polyethylene glycol (PEG). Experimental data showed that the refractive index decreased with increasing the weight ratio to SiO₂ and molecular weight of both PEG and PPG, but PPG was much more effective than PEG. In the case of same molecular weight, PPG modified coating has the higher porosity than PEG modified one. When the weight ratio of PPG to SiO₂ is in a low level, the PPG-containing silica AR coatings exhibit the good abrasion-resistance. PPG is liquid at room temperature and the better solubility than PEG. These effective and economic AR coatings with enhanced abrasion-resistance have potential value in the field of solar thermal collectors.