季铵化聚砜/改性蒙脱土阴离子交换膜的制备与表征

以聚乙烯亚胺(PEI)和二甲基二烯丙基氯化铵-丙烯酰胺共聚物(PAADDA)为改性剂,对蒙脱土K10纳米片进行了包覆。将改性K10添加于氯甲基化聚砜的N,N-二甲基乙酰胺溶液中制备复合膜,经季铵化和碱化处理得到复合的阴离子交换膜。采用傅里叶变换红外光谱、X射线衍射仪、热重分析仪对改性蒙脱土和阴离子交换膜进行了表征,并测试了阴离子交换膜的吸水率、力学性能和离子传导率。结果表明,PEI和PAADDA成功包覆于K10纳米片表面,复合的阴离子交换膜吸水率、热稳定性和力学性能与季铵化聚砜膜相比都有明显改善,PAADDA改性K10含量为5%的阴离子交换膜具有最高的离子传导率,60℃时超过3.0×10-2S/cm。     

咪唑季铵化聚醚砜阴离子交换膜的制备与性能表征

以1-甲基咪唑为季铵化试剂,通过氯甲基化、季铵化、碱化等步骤,成功制备了不同氯甲基化取代度咪唑季铵化聚醚砜(PES-ImOH)阴离子交换膜。并对膜的离子交换容量(IEC)、吸水率、溶胀度和氢氧根传导率等性能进行表征。实验结果表明,当PES-ImOH膜的氯甲基化取代度(DC)为40%~61%,60℃时膜具有适宜的吸水率(24%~80%),较低的溶胀度(15%~44%)。DC为73%时,膜的IEC达到1.85 mmol/g,20℃时的离子传导率达到34 mS/cm,初始分解温度达到190℃。说明PES-ImOH膜在碱性阴离子交换膜燃料电池方面有很好的应用前景。     

高耐碱性交联型聚苯醚阴离子交换膜的制备

以溴化聚苯醚(BPPO)为主链,N,N-二甲基己胺(DMHA),N,N-二异丙基乙胺(DIEA)和三乙胺(TEA)为季铵化试剂,N,N,N′,N′-四甲基-1,6-己二胺为交联剂制备了一系列交联型阴离子交换膜(AEMs),并对交联膜物理和电化学性能进行了表征与测试.结果表明,膜具有明显的微相分离结构、高的离子电导率、优异的尺寸稳定性和化学稳定性.其中接枝N,N-二异丙基乙胺的膜(c-PPO-DIEA)离子电导率在80℃下可达到72.3 mS/cm;在1 mol/L NaOH中经480 h的耐碱性测试发现,膜c-PPO-DIEA的离子电导率能够保留80%以上,表现出良好的耐碱性;将该膜组装成单电池测试,开路电压为0.983 V,在80℃下电流密度200 mA/cm~2时其功率密度达到89 mW/cm~2.     

基于乌尔曼偶联反应制备的密集季铵化型全钒液流电池阴离子交换膜

离子传导率和选择性是全钒液流电池隔膜的两项核心性能指标.本文基于乌尔曼偶联反应设计合成含八苯甲基的双酚单体,然后依次将其聚合、溴甲基化、季铵化制得一系列密集季铵化型阴离子交换膜(QA-OMPFEKs).产物QA-OMPFEK-20 (离子交换容量IEC=1.66 mmolg^-1)的室温SO42-传导率为9.62 mS...     

改性聚酰胺-胺阳离子树状大分子的合成与表征

以甲醇为溶剂、投料比为3.0GPAMAM/N,N-二甲基乙醇胺=1∶16,N,N-二甲基乙醇胺/环氧氯丙烷=1∶1、反应温度50℃、反应时间12h的优化条件下,利用环氧氯丙烷与整代产品进行加成反应,以及环氧氯丙烷与N,N-二甲基乙醇胺进行季铵化反应,对3.0GPAMAM树状大分子进行阳离子改性。并采用红外光谱(FT-IR)、核磁共振(NMR)对产品进行了结构表征。结果表明:所合成的产品与预期产物结构吻合较好,达到预期目标,且阳离子转化率达到90%以上。     

N-长烷基壳聚糖季铵盐的合成及其抗菌活性研究

先用甲醛-甲酸法(eschweiler-clarke反应)合成N,N-二甲基壳聚糖(DMC),再与溴代烷进行Hoffman烷基化反应制备了N-十二烷基-N,N-二甲基壳聚糖季铵盐(DODMC)和N-十六烷基-N,N-二甲基壳聚糖季铵盐(HDMC),用FT-IR、1 H NMR、EA、TG等对产物进行表征。抗菌实验结果表明所合成产物具有较好的抗菌活性,对革兰氏阳性菌S.aureus的抗菌活性优于革兰氏阴性菌E.coli,抗菌活性随着烷基链长度的增加而增强;产物在pH值=5.5比在pH值=7.2条件下表现出更好的抗菌活性;在碱性及中性条件下,HDMC的抗菌活性随着季铵化度的提高而提高,而在酸性条件下抗菌活性则随着季铵化度提高而降低。     

两亲水溶性阳离子聚电解质研究Ⅱ.聚(苯乙烯-丙烯酰胺)的阳离子季铵化改性

疏水性苯乙烯和亲水性丙烯酰胺共聚,得到两亲聚(苯乙烯-丙烯酰胺)(P(St-Am)).P(St-Am)中-CONH2官能团具有反应性,通过氨交换反应,对P(St-Am)的侧链进行功能化改性,N,N-二甲基丙二胺在乙二醇中和P(St-Am)反应生成聚(苯乙烯-N'-丙烯酰胺基-N,N-二甲基丙二胺).以硫酸二甲酯为季铵化试剂,对上述产物进行季铵化反应,得到硫酸二甲酯季铵化聚(苯乙烯-丙烯酰胺).P(St-Am)及其阳离子季铵化改性产物的结构由IR和1H NMR得到了确证.     

聚胍盐离子液体的合成及其在阴离子交换膜中的应用

以溴丙烯、N,N,N′,N′-四甲基胍(TMG)为原料,合成N,N,N′,N′-四甲基-N″-丙烯基胍离子液体(IL),以偶氮二异丁氰(AIBN)为引发剂,将丙烯基胍离子液体聚合成聚胍盐离子液体(PIL).通过核磁共振氢谱(1 H NMR)对离子液体及聚离子液体进行分析,并将二者引入聚砜为基质的阴离子交换膜中,采用流延法制备了聚砜/离子液体复合膜(PSf-IL)和聚砜/聚离子液体复合膜(PSf-PIL).借助红外(FTIR)、扫描电镜(SEM)、热重分析(TGA)和机械性能测试等对两种复合膜的结构及理化性能进行测试.结果表明,当离子液体与聚离子液体添加量相同时,聚砜/聚离子液体复合膜的各项性能均好于聚砜/离子液体复合膜.当质量比PSf∶PIL=1∶0.2时,PSf-PIL复合膜离子交换量为0.68meq/g;80℃时电导率为7.8×10-2 S/cm;经过80℃、400h、KOH(6mol/L)的耐碱性测试后,虽然胍盐离子液体部分降解,但K+会进入膜微结构中,使得电导率不降反升,为初始值的1.17倍,膜质量损失小于3%,IEC由原来的0.68meq/g上升到0.79meq/g.     

膜接触器分离混合气中二氧化碳

以N-甲基二乙醇胺（MDEA）水溶液为吸收剂,采用疏水性聚丙烯中空纤维膜组件（HFPPM）作为膜接触器,研究了膜接触器分离CO2/N2混合气传质性能,主要考察了吸收剂浓度,液速,吸收温度,原料气浓度和气速等因素对CO2吸收性能的影响,比较了同一膜组件不同流程和不同膜组件及膜形态对分离效果的影响,并对膜组件运行的稳定性进行了初步考察,实验结果表明,采用MDEA溶液和HFPPM膜接触器分离CO2/N2混合气具有较快的传质速率和较高的分离效率．     

基于聚乙烯醇/支化聚乙烯亚胺离子交换膜不同烃基对其性能的影响EI北大核心CSCD

以聚乙烯醇/支化聚乙烯亚胺(PVA/BPEI)为基体,分别选用多种卤代烃为季铵化试剂制备阴离子交换膜(AEMs),并采用多种测试方法对膜的关键性能进行表征,以及基于分子结构对结果进行分析讨论。结果表明,以3-氯-1-丙醇为季铵化试剂制备所得的AEM于80℃电导率可达79. 03 m S/cm,IEC值为3. 1 meq/g,且该膜由于羟基在膜内形成的氢键作用使其具有优异的热力学性能、尺寸稳定性和化学稳定性;膜内季铵基团随其疏水链长度及结构的不同对AEMs性能的影响也有所差异,引入含有羟基的柔性侧链可在膜内构成氢键网络形成亲疏水结构,是提高膜综合性能的有效途径。     

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...     

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.……     

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.     

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.     

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.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

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.     

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