聚醚介质中的离子传导机理

以单阳离子导体作为传导模型,通过对阳离子淌度的表征,证实了碱金属盐在聚合物介质中的负温度依赖性。发现在离子传导过程中,离子淌度对其电导率温度依赖性的影响远甚于载流离子数。并运用聚合物链段松驰理论对这种反常离解行为进行了唯象学的诠释。     

丙烯酸-丙烯酸钠共聚物在水溶液中的离解

聚丙烯酸和聚丙烯酸盐是一类重要的水溶性聚合物,也是典型的聚电解质的代表．聚电解质在溶液中可以离解为聚离子和对离子,这一行为是它的根本特性．聚电解质的离解行为与相应的小分子．弱酸和弱酸强碱所生成的盐的离解行为有很大的不同,从而引发了许多实验和理论的研究.早期的工作,大都是用电位滴定的方法研究酸性聚电解质的离解,     

耐温抗盐驱油聚合物溶液黏弹性

对3种不同结构类型的耐温抗盐驱油聚合物〔高分子量聚丙烯酰胺(HPAM)、磺化聚丙烯酰胺(S-HPAM)和疏水缔合聚丙烯酰胺(A-HPAM)〕的溶液黏弹性能进行了研究。在温度85℃下,通过稳态剪切和动态剪切试验,考察了质量浓度和矿化度对聚合物溶液黏弹性的影响。结果表明,随剪切速率增加,溶液表观黏度逐渐降低。质量浓度越高,溶液的储能模量(G')和损耗模量(G″)越大。由动态剪切实验数据,计算得到第一法向应力差(N1)。随质量浓度增加,聚合物溶液的N1逐渐增大;随矿化度增加,聚合物溶液的N1出现不同盐敏感区域,说明不同结构类型的驱油聚合物溶液对矿化度的弹性响应不同。研究结果为高温高盐油藏聚合物驱剂的选择及开发提供了理论参考。     

新型阳离子聚丙烯酰胺离解行为的研究

前文曾报导,以聚丙烯酰胺为母体,通过甲醛为桥梁引入二氰二胺可合成一种新型阳离子聚电解质,简称PAm·MG,它是一种弱聚碱的盐酸盐,结构式如下(S 为取代度):PAm·MG 对含活性艳红染料的废水有明显的絮凝脱色作用,其絮凝效果受聚合物的取代度、介质的pH 以及外加盐浓度的影响,而这些影响因素又直接与聚碱的离解行为或胺基离子化度(指已离子化的胺基占全部胺基的分数)密切相关.为此,本文对影响PAm·MG 离解行为和离子化度的一些因素作进一步探讨,并通过粘度测定考察离解行为对聚合物在水中形态的影响,为PAm·MG 的实际应用提供理论根据.     

不同锂盐对超支化/梳状复合型聚合物电解质的性能影响研究

利用PVA侧链上的羟基的化学活性,采用超支化聚胺-酯对改性纳米SiO_2和PVA接枝改性,并加入不同锂盐,制备了SiO_2-g-HBPAE/PVA-g-HBPAE超支化/梳状复合型聚合物电解质,利用SEM观察了纳米粒子在基体中的分散情况,采用DSC、拉伸实验以及介电谱研究了锂盐种类及添加量对复合体系性能的影响.结果表明,超支化接枝改善了SiO_2和基体的界面相容性;磺酸类锂盐在复合材料中表现出自增塑现象,材料的玻璃化转变温度(Tg)大幅度下降;LiClO_4在基体中的离解能力强于Li CF_3SO_3和Li N(SO_3CF_3)_2;当Li CF3SO3添加量为20%(by mass,下文同)时,聚合物电解质的室温电导率达到最大值2.58×10-6S·cm-1.     

聚偏氟乙烯凝胶电解质组成间相互作用及其凝胶化研究

通过冷却聚偏氟乙烯 (PVDF) 丙烯碳酸酯 (PC)或PVDF PC LiClO4的溶液 ,制备了数个聚合物凝胶 .实验表明 ,聚合物凝胶的凝胶化时间 (tgel)与凝胶温度、聚合物浓度有关 ,且强烈地依赖于体系中盐的浓度 ,因为盐会缩短体系的tgel.凝胶体系中LiClO4的存在提高了其凝胶熔融温度 (Tgm) ,LiClO4的含量越大 ,相应凝胶的Tgm 越高 .用DSC和落球法所测凝胶的Tgm 有较大的差别 .这说明凝胶中可能存在热稳定性好和热稳定性相对较差的两种不同结构部分 .FT IR的研究结果表明 ,凝胶电解质的各组成 (LiClO4,PC和PVDF)间存在较强的相互作用 .对含盐和不含盐的两类凝胶体系的对比研究表明 ,两者不同的凝胶化现象和Tgm 归因于盐与聚合物或溶剂间的络合作用     

聚N-烷基丙烯酰胺结构与性能及外界环境对溶液性能影响

聚N-烷基丙烯酰胺具有温度敏感的特殊性能、其良好的应用潜力成为高分子领域的研究热点。决定该类聚合物温度敏感性的关键因素是聚合物本身的结构,而且与聚合物所处的外界环境也有紧密关系。利用该类聚合物的温敏特性来适应油气田开发中的高温高盐地层具有重要的研究价值。本文综述了聚N-烷基丙烯酰胺结构对聚合物性能的影响,如亲疏水单体比例、温敏单体共聚方式、改性单体种类等;总结了聚N-烷基丙烯酰胺聚合物水溶液性能的影响因素,如不同种类表面活性剂、溶剂、离子强度、剪切速率等。     

磺胺异噁唑印迹聚合物的制备与选择结合性能的研究

以磺胺异唑为模板分子, 二甲基丙烯酸乙二醇酯为交联剂, 分别用甲基丙烯酸和4_乙烯基吡啶为功能单体, 采用牺牲硅胶法合成了磺胺异唑分子印迹聚合物; 通过静态平衡结合法和Scatchard分析法, 系统研究了不同单体对聚合物识别性能和选择性的影响; 对比磺胺异唑和磺胺二甲嘧啶的结合特性, 以4_乙烯基吡啶为功能单体的印迹聚合物具有较好的选择性; Scatchard分析表明, 该印迹聚合物在印迹过程中形成了两类不同的结合位点, 计算了离解常数分别为2.01×10-4 和7.30×10-3 mol/L。     

磺胺异(口恶)唑印迹聚合物的制备与选择结合性能的研究

以磺胺异噁唑为模板分子,二甲基丙烯酸乙二醇酯为交联剂,分别用甲基丙烯酸和4-乙烯基吡啶为功能单体,采用牺牲硅胶法合成了磺胺异噁唑分子印迹聚合物;通过静态平衡结合法和Scatchard分析法,系统研究了不同单体对聚合物识别性能和选择性的影响;对比磺胺异噁唑和磺胺二甲嘧啶的结合特性,以4-乙烯基吡啶为功能单体的印迹聚合物具有较好的选择性;Scatchard分析表明,该印迹聚合物在印迹过程中形成了两类不同的结合位点,计算了离解常数分别为2.01×10-4和7.30×10-3mol/L.     

高铁酸钾在中性、酸性介质中的稳定性

研究了温度、pH、醋酸钠、Fe(Ⅲ)、氯化钠等对K2FeO4,水溶液稳定性的影响.随着温度的升高,K2FeO4在酸性介质中的稳定性逐渐减弱,随pH的增大,K2FeO4的稳定性逐渐增强;在中性介质中醋酸钠能够增强K2FeO4的稳定性,而在酸性介质中,却能够加速K2FeO4的分解;在中性和酸性介质中,三价铁盐的存在能够加速K2FeO4的分解;氯化钠能增强K2FeO4的稳定性.     

预混天然气在多孔介质燃烧器中的燃烧与传热

在一台小型渐变型多孔介质燃烧器上进行了预混天然气燃烧与传热试验研究，探讨了天然气速度和多孔介质厚度对多孔介质燃烧室的温度分布、排烟温度和流动阻力的影响。结果表明，天然气在渐变型多孔介质燃烧器中燃烧稳定，燃烧室与水冷夹套间的换热受天然气速度和多孔介质厚度影响，换热效果比空管中燃烧明显增强，同时预混天然气通过多孔介质的进出口压差随着天然气速度和多孔介质厚度的增加而增加。     

Mathematical Model of Foam Flowing Characteristics by Snap-Off Mechanisms at Steady State in Porous Media

Flow characteristics and regeneration processes of foams were influenced by lamella properties and pore-throat structure in porous media. In this article, porous media was simplified as a bunch of constricted capillary tubes according to grain size, pore-throat radius, and immobile water saturation in porous media. Based on an analysis of forces upon liquid lamella, a mathematical model of foam migration and regeneration at steady state was established according to the mass conservation law and the momentum conservation law in porous media. The model could be used to calculate some important parameters in porous media, such as pressure distribution, shearing stress, lamella morphology, liquid-layer thickness, regeneration bubble size, etc. A series of flow experiments were carried out to investigate the influence of liquid properties and pore-throat structure on flow characteristics and resistance behavior of foams in porous media. The experimental results showed that pressure distribution monotonously decreased along porous media. The theoretical results were in good agreement with the experimental results. Foam structure, that is, foam quality was an important factor upon foam resistance behavior in porous media. The strongest resistance ability of foams was achieved at foam quality of 85% in porous media.      

氯诺昔康与中性及电荷型β-环糊精衍生物的包合作用

采用溶解度法研究了不同pH值下氯诺昔康与中性及电荷型β-环糊精衍生物的包合作用．结果表明,氯诺昔康与3种环糊精都形成了1：1的包合物．以包合常数作为包合作用的量度,在酸性和中性条件下包合能力较碱性强,其中磺丁醚-β-环糊精（SBE移CD）在酸性条件下包合常数最大．电荷型伊环糊精除了通常的疏水作用力为主客体间包合驱动力外,还存在额外的静电包合作用力．     

The dielectric constant and salt effects upon the acid hydrolysis of methyl propionate

The hydrolysis of methyl propionate catalyzed by hydrochloric acid has been studied at three temperatures in water-acetone media and in water media containing different concentrations of sodium nitrate. The specific velocity constants in wateracetone media were shown to conform to the theory for reaction between positive ions and dipolar molecules. bender's mechanism for ester hydrolysis has been accepted as plausible in view of the kinetics in mixed media. The specific velocity constants in the sodium nitrate solutions were shown to conform to the theory of Euler.     

A rapid fluorescence based method for the quantitative analysis of cell culture media photo-degradation

Cell culture media are very complex chemical mixtures that are one of the most important aspects in biopharmaceutical manufacturing. The complex composition of many media leads to materials that are inherently unstable and of particular concern, is media photo-damage which can adversely affect cell culture performance. This can be significant particularly with small scale transparent bioreactors and media containers are used for process development or research. Chromatographic and/or mass spectrometry based analyses are often time-consuming and expensive for routine high-throughput media analysis particularly during scale up or development processes.     

低温高活性熔铁催化剂上的超临界相费托合成反应

在固定床反应器中超临界相条件下研究了熔铁催化剂上的费托合成反应,发现在超临界介质中反应物和产物更容易扩散,较好地抑制了催化剂表面非活性碳的沉积,从而提高了费托合成反应中的CO转化率和烯烃选择性,增加了链增长因子,降低了甲烷选择性.同时,考察了超临界介质、反应温度、压力、H2/CO比和空速等条件对费托合成反应的影响.结果表明,C5-8正构烷烃在催化剂活性温度下都是适宜的超临界介质.当温度和压力都在介质的临界点以上时,介质表现出较好的传质与传热性能,可改善费托合成反应性能.     

一种凝血酶亲和色谱介质的制备方法

对凝血酶-琼脂糖亲和色谱介质的制备方法进行了研究。首先使用凝血酶和溴化氰活化的琼脂糖制备凝血酶-琼脂糖亲和色谱介质,然后用生色底物法考察亲和色谱介质上凝血酶的活性,以凝血酶活性为指标对最佳偶联条件进行了优化。结果表明最佳条件为使用pH 8.3的Na₂CO₃-NaHCO₃溶液(含0.5 mol/L NaCl)为缓冲溶液,凝血酶用量为每1 g色谱介质加入凝血酶200 U,室温反应10 h。在最佳条件下所制备的色谱介质有较好的稳定性,在4℃条件下存放40天,亲和介质上的凝血酶活性仍有70.6%保留。该亲和色谱介质可广泛用于含凝血酶抑制剂的天然药物筛选和分离纯化。     

Robustness of virus removal by protein A chromatography is independent of media lifetime

The robustness of virus clearance with respect to protein A media reuse was demonstrated using media with four matrix chemistries: Protein A immobilized ProSep A, Poros A50, Protein A ceramic Hyper DF and MabSelect SuRe, an alkali resistant protein A ligand. Endogenous retrovirus clearance, step yield, impurity clearance and other performance parameters were evaluated periodically in media cycled up to 300 times. Media lifetime was generally limited by either declining step yield or media fouling. However, clearance of endogenous retrovirus remained in an acceptable range, either increasing or remaining constant. Multiply cycled media were tested for clearance of three viruses (SV40, X-MuLV, and MMV); clearance was comparable to na?ve media. Overall, virus clearance by protein A chromatography appears to be extremely robust with respect to media age.     

Preparation of radioactive chloramine-B by isotopic exchange with radioactive chlorine

The exchange between chloramine-B and radioactive chlorine has been carried out in various media. The exchange is slow in strong acid and very weak acid media. Its maximum is at pH 3.3. There is no exchange in alkaline media. Optimum conditions for the preparation of radiochloramine-B with high specific activity are reported.     

Novel in situ polymerized coatings for hydrophobic interaction chromatography media

Hydrophobic interaction chromatography (HIC) and other capture media are typically produced by grafting different ligands to base matrices at defined surface densities. This often complicates media production. An alternative approach to media involving in situ radical initiated polymerization was used to graft polymer coatings directly at Sepharose(R) polymeric base matrices. This method appears suitable for producing many different chromatography media on a variety of base matrices. In the present study, it also favorably increased the solution pressure-flow properties of a Sepharose base matrix used to produce HIC media. A wide range of HIC media could be produced by simply varying the reaction ratio of butyl vinyl ether, and hydroxybutyl vinyl ether. The new HIC media was evaluated using five test proteins (bovine serum albumin, ribonuclease A, alpha-chymotrypsinogen A, myoglobin and alpha-lactalbumin). The media exhibited classic HIC behavior, predictably controlled hydrophobicity, plus good protein selectivity, capacity (70mgprotein/ml gel) and often total protein recovery. By modifying the degree of matrix hydrophobicity, we could also reduce effects of protein denaturation often seen with conventional HIC and observed as multiple peaks in the chromatograms. Separation of crude protein extracts from Eschericha coli, expressing a green fluorescent protein (GFPuv) and, a more hydrophobic, recombinantly-modified, tyrosine-tagged green fluorescent protein (YPYPY-GFPuv), was also performed. These proteins were very stable, exhibited significantly different retention times, and could be used to study the ability of the media to work with complex protein mixtures. Such GFP mutants appear ideal for characterizing the performance of chromatographic media.