两亲聚合物溶液的流变规律及影响因素

针对大庆油田应用的两亲聚合物,通过扫描电镜揭示了其微观结构;利用MCR301流变仪测定了两亲聚合物的流变性,使用Carreau模型对流变曲线进行了拟合,确定了Na+、K+、S2-浓度越高,体系的黏度越低,η0越小;Ca2+、Mg2+浓度增加,η0先增加后降低。同时,研究了温度对两亲聚合物溶液黏度的影响,浓度低于临界聚集浓度(CAC)值时,浓度越高,两亲聚合物溶液的黏度对温度越敏感,而浓度高于CAC值后的规律则相反。因此,对于两亲聚合物驱,应选择浓度尽可能高于CAC值的体系。     

疏水缔合聚合物溶液的流变性研究

流变性是疏水缔合聚合物溶液在应用时最受关注的性能。寻找分子结构溶液结构流变性的关系有助于进一步理解水溶性疏水缔合聚合物溶液内部结构的本质。因此对比研究疏水缔合聚合物溶液(HAP)在浓度、矿化度、剪切速率等因素影响下的剪切特性。     

荧光探针研究温敏大分子单体在水溶液中的热缔合行为

通过芘荧光探针研究了基于双丙酮丙烯酰胺(DAAM)的新型温敏大分子单体在溶液中的热缔合行为。结果表明,温敏大分单体的临界缔合浓度(CAC)取决于丙烯酰胺(AM)与DAAM的组成比。DAAM的比例越大,CAC就越低;随着温敏大分子单体中DAAM的含量、大分子单体浓度和溶液pH的增加,芘的I1/I3值降低,疏水缔合作用增强,且温度越高,I1/I3值越低,呈现明显的热缔合行为。温敏大分单体的热缔合行为随组成、浓度和pH变化的这种性质有可能在新型温敏聚合物及凝胶的合成设计上获得应用。     

离子型表面活性剂与疏水缔合聚丙烯酰胺的相互作用

通过动态流变、幂律模型、动/静态激光光散射以及荧光光谱考察了丙烯酸十八酯(ODA)、丙烯酰胺(AM)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)经超声辅助(Ultrasonic assist)自由基共聚制得的疏水缔合聚丙烯酰胺(UHAPAM)的动态流变性及其与阴阳离子型表面活性剂(十二烷基硫酸钠(SDS)和十六烷基三甲基溴化铵(CTAB))之间相互作用关系。结果表明,这种假塑性流体的临界聚集浓度(CAC)为0.27%。当UHAPAM水溶液浓度高于CAC时,SDS影响分子间疏水缔合,使水溶液表观粘度下降;CTAB反而改善疏水缔合性,使表观粘度明显增加,但增粘效果越来越缓和。表面活性剂均使溶液触变性降低。同时,形状因子(〈Rg〉/〈Rh〉)在SDS-UHAPAM体系里随SDS浓度的增加而增加,聚合物分子线团变得相对舒展;而在CTAB-UHAPAM体系里则随CTAB浓度增加而出现最低值,聚合物分子链段历经一个卷缩然后舒展的过程。在SDS和CTAB胶束中加入UHA-PAM,SDS聚集数先减小后增大,而CTAB聚集数则持续增加。     

β-环糊精为核的阳离子星形聚合物的合成及应用

以β-环糊精(β-CD)和2-溴异丁酰溴进行酰化反应合成得到Br-β-CD。然后采用原子转移自由基聚合(ATRP)技术,以甲基丙烯酸二甲氨基乙酯(DMAEMA)和丙烯酰胺(AM)为共聚单体,Br-β-CD为引发剂,CuBr为催化剂和2,2′-联吡啶(bpy)为配位剂,合成了阳离子星形聚合物。利用FT-IR、1H-NMR对所制备的引发剂和阳离子星形聚合物进行了表征。同时利用阳离子星形聚合物对阴离子的碱性膨润土进行改性,用于吸附溶液中的重金属Cr6+,考察了改性剂用量、吸附时间、改性剂浓度、溶液pH值对复配体系吸附Cr6+的影响。结果表明,在研究范围内,碱性白土经改性阳离子星形聚合物改性后,对Cr6+的吸附率由原来的15%提高到57%。     

β-环糊精为核的阳离子星形聚合物的合成及应用EI北大核心CSCD

以β-环糊精(β-CD)和2-溴异丁酰溴进行酰化反应合成得到Br-β-CD。然后采用原子转移自由基聚合(ATRP)技术,以甲基丙烯酸二甲氨基乙酯(DMAEMA)和丙烯酰胺(AM)为共聚单体,Br-β-CD为引发剂,CuBr为催化剂和2,2′-联吡啶(bpy)为配位剂,合成了阳离子星形聚合物。利用FT-IR、1H-NMR对所制备的引发剂和阳离子星形聚合物进行了表征。同时利用阳离子星形聚合物对阴离子的碱性膨润土进行改性,用于吸附溶液中的重金属Cr6+,考察了改性剂用量、吸附时间、改性剂浓度、溶液pH值对复配体系吸附Cr6+的影响。结果表明,在研究范围内,碱性白土经改性阳离子星形聚合物改性后,对Cr6+的吸附率由原来的15%提高到57%。     

疏水改性聚合物P(AM/AA/POEA)的溶液性质

应用黏度法研究了新型缔合聚合物P(AM/AA/POEA)的溶液流变性质。该聚合物由丙烯酰胺(AM)、丙烯酸(AA)和少量2-苯氧乙基丙烯酸酯(POEA)组成。结果表明,共聚物中疏水嵌段的数量、长度和离子基团含量对溶液流变性质有重要影响,这种离子型聚合物的溶液性质同时受疏水基团的缔合作用和离子基团间的静电排斥作用的共同影响。同时进一步研究了聚合物浓度和pH值对溶液黏度的影响。研究结果表明,这类聚合物在较宽pH值范围黏度较高,说明在实际应用中可操作的范围较宽。     

基于聚醚的热增黏接枝聚合物的合成及性能

聚合物水溶液黏度通常会随温度升高而降低。为了解决高温下聚合物溶液的增黏难题,文中利用聚醚(F127)分别与丙烯酸、丙烯酰胺、2-丙烯酰胺基-2-甲基丙磺酸接枝共聚,得到了系列热增黏聚合物。考察了聚合条件、聚合物浓度、亲水单体的性质对聚合物溶液热增黏能力的影响。结果表明,聚合物浓度越高、聚合物相对分子质量越高,聚合物的热增黏性能越好,热缔合温度也越低。     

疏水缔合羟乙基纤维素水溶液的流变性及驱油性能

研究了疏水缔合改性羟乙基纤维素(BHEC)水溶液的流变性和驱油性能。结果表明,BHEC的临界缔合浓度在4000 mg/L左右,其增粘性能是HEC的近22倍;NaCl对BHEC水溶液有促进作用,当NaCl含量达到100000 mg/L时,BHEC的表观黏度仍然稳定在699.9 mPa.s,说明其具有良好的抗盐性。BHEC水溶液达到临界缔合浓度才具有粘弹性,并随着聚合物浓度的增加,聚合物溶液的粘弹性越显著,振荡频率越高,损耗因子越低。浓度为6000 mg/L的BHEC水溶液可在水驱基础上提高原油采收率25%~32%。     

阳离子丙烯酸酯共聚物表面活性剂的结构及溶液性能

通过自由基溶液共聚合法合成了无规型阳离子丙烯酸酯共聚物表面活性剂,利用红外光谱(FT-IR)和核磁共振谱(1H-NMR和13C-NMR)对聚合产物的结构和组成进行了表征,考察了浓度、温度等对聚合物丙酮溶液的增比黏度和聚合物水溶液表面张力的影响。结果表明,聚合物丙酮溶液的增比黏度随溶液浓度增加总体呈现上升趋势,在相同溶液浓度下,其增比黏度随温度升高呈先降低后升高再降低的趋势;聚合产物可将水溶液的表面张力降低到43mN/m,其临界胶束浓度为0.8 g/L;聚合物水溶液的表面张力随温升高而降低,且随溶液pH值增大而增大。     

紫脲酸铵分光光度法测定复盐法水氯镁石脱水产品中氧化镁

对于水氯镁石的复盐(C6H5NH2·HCl·MgCl2·6H2O)法脱水产品中微量MgO含量的测定,采用了直接测定样品水溶残渣中镁含量而得MgO含量的方法代替传统的间接法,获得了更准确的结果。用紫脲酸铵分光光度法测定了水溶残渣用稀H2SO4溶解后溶液中微量镁,研究了金属镁离子与显色剂的络合比、溶液酸度、显色时间对显色的影响,以及盐酸苯胺阳离子、Fe3+、Zn2+、Ba2+、Ca2+、Ni2+、Co2+等离子对显色的干扰及其消除。并采用修正法消除了显色后残余显色剂对测定镁的影响。结果表明,在镁离子浓度0~2mmol/L范围内,修正吸光度与镁离子浓度呈线性关系,摩尔吸光系数为2.45×102 L/(mol·cm)。加标镁离子的测定结果证明该法具有较高的精密度和准确度（加标回收率近100%）,适合于水氯镁石脱水产品中总MgO含量的准确测定。     

微波均相沉淀法制备Nd:YAG纳米粉体及其表征

以Al(NO3)3,Y(NO3)3为母盐,尿素为沉淀剂,添加占母盐质量为8%的(NH4)2SO4,以不同浓度的Nd3+取代Y3+,采用微波均相沉淀法制备了具有良好分散性和可烧结性、平均粒径为71nm的Nd:YAG纳米粉体。利用IR、DTA-TG、XRD、TEM、LD等技术对YAG前驱物及其煅烧粉体进行表征。结果表明:采用微波均相法,前驱体在1100℃下煅烧,可得到分散良好的纯YAG相,无YAP、YAM中间相出现,且YAG的单相程度不随Nd3+掺杂浓度的增加而变化。     

ANSYS在水电站固卷机架结构设计中的应用

针对糯扎渡水电站2x800kN固定卷扬机的设计,分析了固卷的计算工况及计算载荷,用ANSYS软件建立SHELL63弹性壳单元模型,对金属结构的连接、约束、载荷进行有效处理,对固卷机架的应力、变形进行有限元计算,并对机架进行了模态分析,为结构系统的振动特性分析、振动故障诊断和预报以及结构动力特性的优化设计提供依据。     

环糊精二聚体与双支化两亲聚合物包合体系的构筑

将实验室自制的环糊精二聚体(66βCDsu)与双支化两亲聚合物(P(AM/BHAM/NaA))加入到水溶液中,发生包合作用构筑包合体系。研究该体系的增黏及溶液流变学特性,并采用荧光光谱仪、扫描电镜及差示扫描量热仪等研究包合体在溶液中的包合机制及结构形态。结果表明,由于P(AM/BHAM/NaA)中1个疏水单体中存在2个疏水基团(正十六烷基和苄基),因此环糊精与疏水单体BHAM最大摩尔包合比为2∶1,完全包合后溶液中没有游离态疏水基团,因此溶液不存在临界聚集浓度(CAC)。当环糊精与BHAM摩尔包合比为1∶1,体系存在明显的CAC,这是由于环糊精首先包合双支化疏水单体中的苄基形成包合体,而正十六烷基依然存在于水溶液中。当P(AM/BHAM/NaA)浓度为800mg/L时,该体系中存在2种聚集方式,一种是疏水基团的疏水缔合;另一种是包合作用。通过扫描电镜证明了不同体系的微观聚集形态。     

Dynamic behaviors of lipid-like self-assembling peptide A6D and A6K nanotubes

Nanoscience and nanotechnology require development of nanomaterials that are amiable for molecular design from bottom up. Molecular designer self-assembling peptides are one of such nanomaterials that will become increasingly important for the endeavor. Peptides have not only been used in all aspects of biomedical and pharmaceutical research and medical products, but also have had enormous impact in nascent field of designed biological materials. We here report the dynamic structures of lipid-like designer peptide A6D (AAAAAAD) and A6K (AAAAAAK) that undergo self-assembly into nanotubes in water and salt solution. We not only analyzed their self-assemblies using dynamic light scattering to determine the critical aggregation concentration (CAC), but also use atomic force microscope to observe their nanostructures. We also propose a simple scheme by which these lipid-like peptides self-assemble into dynamic nanostructures. Since the knowledge of CAC is important for uses of these peptides for a variety of applications, these findings may have significant implications in the study of molecular self-assembly and for a wide range of utilities of designer self-assembling peptide materials.     

微量元素对镀锌层微观结构的影响

研究了硫酸盐镀锌液中常见金属微量元素离子Pb^2 ,Cu^2 ,In^ ,Fe^2 对沉积层的外观形貌，显微组织，结晶择优取向和耐蚀性的影响，研究表明，不同的要质对镀层的外观，显微组织以及晶面的择优取向的影响不同，铅离了孤引入降低了镀层的外观质量和（002）晶面的强度，镀离子的引入使镀层的外观质量和（002）昌面的强度均得到提高，起到了无机光亮剂的作用。     

Aqueous solution-based synthesis of rare earth-doped metal oxide thin films

Rare earth-doped TiO₂ thin films have been successfully formed on glass and Si wafer substrates from aqueous solution through equilibrium reaction between metal–fluoro complex and metal oxide, in which Ln³⁺–ethylenediaminetetraacetic acid (EDTA) complex (Ln: rare earth metal) was added into the reaction solution. Ln/Ti ratio and crystalline structure of the film could be controlled by varying the initial concentration of Ln³⁺–EDTA complex solution. The obtained Ln-doped films were densely-packed and had no cracks.     

Poly(L-cysteine) as an electrochemically modifiable ligand for trace metal chelation

The short-chain (n approximately equal to 50) homopolymer poly(L-cysteine) (PLC) has been previously studied for use as a novel metal chelator. PLC exhibits reversible oxidation-reduction chemistry involving the thiol groups of the cysteine (Cys) residues. Previously, chemical oxidation of the PLC immobilized on silica showed that metal binding capacity was minimal in the oxidized state. In this study, Cys and PLC are immobilized on a glassy carbon disk electrode (GCE) to study these redox processes and how they impact metal binding and release. Voltammetric and chronoamperometric methods were employed to demonstrate nearly monolayer coverage of both immobilized Cys monomer and immobilized PLC on GCE. The PLC-GCE exhibited a maximum metal binding capacity for Cd2+ of approximately 11 Cd2+ ions/chain. No detectable metal binding capacity was observed for oxidized PLC. The bound metals were capable of being efficiently released through disulfide bond formation and tertiary structure changes by means of repetitive oxidative pulses. The Cys-modified electrode exhibited a metal binding capacity for Cd2+ of approximately 1 Cd2+/Cys. Oxidized Cys did retain a significant capacity following oxidation, likely as a result of complexation with the terminal carboxylate site and unoxidized thiols. A glycine (Gly)-modified electrode was also evaluated as an amino acid control. Minimal Cd2+ binding was observed. Further metal binding studies were conducted using PLC-GCE with single metal solutions of Co2+, Cu2+, Ni2+, and Pb2+, as well as a multimetal solution composed of equal concentrations of all five target metals. The observed metal binding trend was as follows: Cu2+ > Cd2+ > Ni2+ > Pb2+ > Co2+. All metals were quantitatively released upon oxidation of PLC using the same anodic potential, 600 mV vs Ag/AgCl.     

Photocatalytic activity of manganese, chromium and cobalt-doped anatase titanium dioxide nanoporous electrodes produced by re-anodization method

Transition metal-doped TiO₂ electrodes were prepared by re-anodization and characterized. The structure of these electrodes was investigated by X-ray diffraction and electron diffraction, which mainly showed typical characteristic anatase reflections without any dopant-related peaks. The amount of transition metal dopant in TiO₂ was kept at approximately 1.0 at.%, as measured by energy dispersive X-ray spectroscopy. The effects of different types of dopants on the photocatalytic activity were revealed by measuring the degradation of an organic aqueous solution containing a dye (acid red G) using a combination of ultraviolet (UV) light energy in the presence of these electrodes. The photocatalytic efficiency was remarkably enhanced by the incorporation of Mn ²⁺ and Cr³⁺. Mn²⁺ showed the most significant enhancement. However, Co²⁺ accelerated the rate of acid red G degradation only slightly. Langmuir-Hinshelwood rate expression was employed for the degradation of acid red G by UV/TiO₂ electrodes system. The adsorption equilibrium constant, the rate constant, and the initial degradation rate were determined for different electrodes. The effect of the concentration of Mn²⁺ on the degradation of acid red G was also investigated and the results showed that there is an optimal value (about 1.0 at.%) of the concentration of Mn²⁺ for inducing faster degradation of the dye. The enhanced photocatalytic degradation rate of acid red G in the presence of transition metals is attributed to the increase of the charge separation in these systems.