新型缔合聚合物P(AM/POEA)溶液的流变性质

应用黏度法和动态模量研究了新型缔合聚合物P(AM／POEA)的溶液流变性质。该聚合物由丙烯酰胺(AM)和少量2-苯氧乙基丙烯酸酯(POEA)(n(POEA)≤1．0％)组成。结果表明,共聚物的微结构对其溶液的流变性能有重要影响。嵌段共聚物(BP系列)具有显著的增黏能力,而无规共聚物(RP系列)则没有这种作用。这种由分子间的疏水缔合作用而产生的疏水缔合增黏能力与疏水嵌段的数量和长度密切相关．同时进一步研究了聚合物浓度、盐浓度、温度和剪切速率对溶液黏度的影响。动态模量测试表明,该聚合物缔合体系在实验浓度范围内黏性响应占有优势。     

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。     

聚合物P(NaAMPS-VCL-DVB)分子结构对其温敏缔合行为的影响

采用可见分光光度计、变温核磁共振氢谱、流变仪等,从浊点和黏度变化方面研究了2-甲基-2-丙烯酰胺基丙磺酸钠(NaAMPS)/N-乙烯基己内酰胺(VCL)/二乙烯苯(DVB)聚合物PAVD在水溶液中的温敏缔合作用,揭示了PAVD分子结构对其温敏缔合作用的影响规律。可见分光光度计和变温核磁共振氢谱对PAVD水溶液相变过程的跟踪研究表明,聚合物分子中VCL含量越高,浊点越低,且变温核磁共振氢谱测试表明,PAVD分子VCL侧链上亚甲基链段会随着温度的升高而变为疏水性,进而产生疏水缔合作用;流变测试表明,只有当聚合物分子中VCL含量处于一定范围内时,其溶液会出现明显的温敏增稠现象,且VCL含量越高,临界增稠温度越低,温敏增稠现象越显著。最后基于临界增稠温度和浊点的对比分析,对聚合物水溶液的温敏缔合过程进行探讨。     

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。     

AM-STD-NaAMPS三元疏水缔合共聚物的表征及耐热性能

以自制的疏水单体苯乙烯衍生物(STD)和丙烯酰胺(AM)、2-甲基-2-丙烯酰胺基丙磺酸钠(NaAMPS)为原料,合成了三元疏水缔合水溶液共聚物PASA。用红外光谱、核磁共振1H谱和DSC分析证实了共聚物的结构,采用元素分析测定了聚合物的组成,通过原子力显微镜对聚合物溶液形态的表征,证实了PASA水溶液疏水微区的存在。TG分析显示PASA具有优良的耐热性能,其分解温度高达312℃。PASA浓度为0.1g/dL时,表观粘度达208mPa.s,表明了其聚合物具有优良的增粘能力。     

聚合物P(NIPAM-AM-NPA)的合成及溶液性能

以丙烯酸壬基酚聚氧乙烯酯(NPA)、丙烯酰胺、N-异丙基丙烯酰胺为单体,采用自由基水溶液聚合方法制备了水溶性共聚物P(NIPAM-AM-NPA)。采用FT-IR、1H-NMR对该共聚物以表征;研究了共聚物浓度、温度以及不同电解质对共聚物溶液性能的影响。结果表明,随着盐浓度的增加,聚合物溶液表观黏度有较大幅度上升。在相同情况下,NaCl的增粘效果最为显著,而MgCl2和CaCl2则影响不大。该共聚物的盐水溶液在升温条件下可保持良好的增粘作用,适当条件下还会出现黏度随温度升高而上升的独特现象。     

温敏聚合物正辛基苯乙烯/N,N-二乙基丙烯酰胺/丙烯酰胺合成及溶液性能

采用实验室自制的疏水单体对正辛基苯乙烯(OBS)、温敏单体N,N-二乙基丙烯酰胺(DEAM)及亲水单体丙烯酰胺(AM),利用氧化-还原胶束聚合法共聚合成温敏聚合物,并对产物进行红外光谱、核磁共振结构表征,结果表明合成产物为目标聚合物。研究了聚合物溶液的温度敏感性,在不同盐浓度(NaCl,CaCl_2)中的敏感性及与阴离子表面活性剂的复合效应;聚合物溶液随温度的升高黏度出现先增加后降低再增加的变化特点,在45℃黏度达到了最大值;聚合物溶液随着NaCl浓度增加,黏度逐渐增加再逐渐下降又上升的特点,最大黏度处NaCl浓度为10000 mg/L;随着CaCaCl_2浓度的增加,出现黏度逐渐增加又下降的特点,最大黏度处为CaCaCl_2浓度500 mg/L;阴离子表面活性剂和聚合物溶液复合后溶液黏度增加,而且相同浓度的表面活性剂对溶液表观黏度的贡献为:十二烷基硫酸钠十二烷基磺酸钠十二烷基苯磺酸钠。     

非离子型疏水缔合聚合物PBAM的溶液性能

由丙烯酰胺和N-苯基对烷基丙烯酰胺采用水溶液自由基胶束聚合法合成疏水缔舍聚合物PBAM。研究了共聚物浓度、盐浓度、温度及表面活性剂浓度对共聚物溶液粘度的影响。结果表明,当聚合物的浓度大于临界缔合浓度时溶液的粘度怠剧增加;NaCl的加入使得溶液的粘度下降,但适当结构的聚合物表现出较好的抗盐能力;聚合物浓度恒定时,溶液粘度随表面活性剂SDS浓度的增加急剧增加,达到最大值后迅速下降。聚合物稀溶液的流变行为呈现牛顿流体的性质。     

基于NIPAM和HEMA的温敏性共聚物水溶液性能研究

以N-异丙基丙烯酰胺(NIPAM)、甲基丙烯酸羟乙酯(HEMA)、丙烯酰胺(AM)、丙烯酸(AA)为原料,采用水溶液自由基聚合法制备了N-异丙基丙烯酰胺基温敏水溶性共聚物P(NIPAM-HEMA-AM)和P(NIPAM-HEMA-AM-NaAA)。研究了无机盐及聚合物结构对共聚物低临界溶解温度(LCST)的影响,考察了共聚物浓度、盐浓度、表面活性剂浓度对共聚物溶液流变性能特别是粘温特性的影响。结果显示,随着盐浓度的增加,共聚物溶液的LCST呈下降趋势。共聚物浓度较高时,在LCST附近表现出显著的升温增稠性。在P(NIPAM-HEMA-AM-NaAA)溶液中加入NaCl后溶液黏度增加,升温增稠效应明显。     

溶液自由基法高分子量聚丙烯腈的合成

采用以偶氮二异丁腈(AIBN)为引发剂,丙烯腈(AN)与丙烯酰胺(AM)在二甲亚砜(DMSO)溶剂中的自由基溶液共聚合,考察了单体浓度,单体配比,引发剂含量,反应温度和聚合时间等对共聚反应的影响。分别用称量法和乌氏黏度计测定了反应的转化率和聚合物的相对分子质量,用红外光谱对聚合物的结构进行了分析。研究结果表明,提高反应温度及引发剂含量,则转化率升高,分子量下降。单体浓度越高,分子量及转化率均可提高。这符合自由基聚合的一般规律。通过工艺优化,共聚物的转化率可达90%以上,黏均分子量约21万。     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.