室温固化柔韧性水性环氧固化剂的合成与性能

拟合成一种室温固化柔韧性水性环氧固化剂。首先在工艺条件(TETA/EPON 828摩尔比为2.2/1,反应温度65℃,反应时间4.0 h)下,滴加液体环氧树脂EPON 828到三乙烯四胺(TETA)的丙二醇甲醚(PM)溶液中,对TETA扩链反应,合成出TETA-EPON 828加成物;然后在反应温度70℃,反应时间3h的条件下,滴加聚醚多元醇二缩水甘油醚(DGEPG)到TETA-EPON 828加成物的PM溶液中再进行扩链反应,合成出TETA-EPON 828-DGEPG加成物,最后除去大部分PM溶剂后,在55℃左右,滴加蒸馏水到TETA-EPON 828-DGEPG加成物中,将其稀释到固含量为52%左右。所合成出的水性环氧固化剂与液体环氧树脂所形成的双组分室温固化涂膜,具有良好的柔韧性和耐冲击性。并用水溶解性实验及红外光谱等对TETA-EPON 828-DGEPG进行了表征。     

水性环氧固化剂制备及其对涂膜性能的影响

将环氧树脂E-44与三乙烯四胺(TETA)形成的加成物接枝到聚天冬酰胺(PAM)大分子链上,形成聚酰胺-胺-环氧梳形接枝聚合物,以丁基缩水甘油醚部分封端,制备了非离子型水性环氧固化剂。研究了PAM接枝该加成物的比率、接枝加成物在加成物中的含量、伯胺封端量对固化剂性能的影响,并与市售水性环氧涂膜性能进行了比较。试验结果表明,多胺加成物接枝率20%、接枝含量25%、伯胺封端量25%的固化剂体系稳定性良好,与现有的市售水性固化剂性能相比,其固化的环氧体系的柔韧性和耐冲击性能有大幅的提高。     

自乳化水性环氧树脂的制备

采用聚醚醇二缩水甘油醚(PEGGE)、乙醇胺(MEA)及冰乙酸对双酚A环氧树脂(DGEBA)化学改性,在不需Lewis酸催化剂条件下制备低污染、高性能水性环氧树脂。首先,在物料摩尔比(MEA/PEGGE)2∶1,反应温度55℃,反应时间4h下,用PEGGE对MEA扩链合成MEA-PEGGE加成物;然后,在物料摩尔比(DGEBA/MEA-PEGGE)2∶1,反应温度65℃,反应时间5h下,用MEA-PEGGE加成物对DGEBA扩链,合成DGEBA-MEA-PEGGE加成物;再采用冰乙酸与DGE-BA-MEA-PEGGE加成物成盐,制备出具有良好水溶解分散性能的自乳化水性环氧树脂。该树脂涂膜性能优良,具有良好柔韧性和耐冲击性,改善了普通环氧树脂性能较脆的缺陷。     

乳化型水性环氧树脂固化剂的合成与性能研究

在三乙烯四胺(TETA)的分子链段上引入醇羟基、环氧基团,使其改性为亲水亲油的两亲性化合物,即乳化型的水性环氧树脂固化剂,兼具乳化和固化功能.采用封端剂调节亲水亲油平衡值(HLB)使乳化固化性能最佳.激光粒度分析仪的测试乳化环氧树脂粒径在200nm左右.涂料涂膜后的性能测试:表干时间2h左右;涂膜后4天其硬度即达到稳定...     

水性含磷环氧化合物的合成与性能

对9,10-二氢-9-氧杂-10-磷杂菲-10-氧化物(DOPO)改性合成水性含磷环氧化合物。首先,以酚醛环氧树脂F-51和DOPO(初始F-51环氧基与DOPO摩尔比为3∶2)合成出F-51-DOPO加成物。然后,在摩尔比(n(F-51-DOPO的环氧基)/n(MEA))为1∶1下,F-51-DOPO加成物与乙醇胺(MEA)反应合成出F-51-DOPO-MEA加成物;最后,在摩尔比(PEGGE环氧基/F-51-DOPO-MEA)为2∶1下,F-51-DOPO-MEA加成物与聚醚醇二缩水甘油醚(PEGGE)反应,合成了F-51-DOPO-MEA-PEGGE加成物。性能研究结果表明,其在室温下能均匀分散于水性体系中,与涂膜中的环氧树脂基材相容性良好;并可使涂膜在保持良好硬度前提下,耐冲击性明显得到提高。热重分析结果表明,其可使固化涂膜在450~800℃高温下的残炭率和耐热性显著提高。氧指数测定结果表明,其能有效提高水性环氧树脂材料的极限氧指数(LOI)及阻燃性能。     

自乳化型非离子水性环氧树脂固化剂的合成与性能研究

在三乙烯四胺(TETA)的分子链段上通过两步扩链法接入环氧基团,将亲水性多乙烯多胺改性成为亲水亲油的两亲性化合物,即自乳化非离子水性环氧树脂固化剂,兼具乳化和固化功能.激光粒度分析仪测试乳化环氧树脂平均粒径在1μm左右,对该水性环氧涂料涂膜后的性能测试表明:表干时间1.5h左右,涂膜6d后硬度达到稳定值,硬度为4H,涂膜附着力达到1级,涂膜的透明性及耐腐蚀性都较好.     

PEG改性环氧树脂固化剂的合成与性能研究

采用三乙烯四胺(TETA)与具有3个环氧基团的三羟甲基丙烷三缩水甘油醚(TMPEG)进行接枝,使其得到具有3个伯胺和6个仲胺的加成产物(A)。再将(A)与聚乙二醇(PEG)改性后的环氧树脂(B)进行接枝得到(C),然后用苯基缩水甘油醚(PGE)进行封端,产物加去离子水分散即为PEG改性环氧树脂固化剂(D)。对影响本实验的时间、温度和物料比进行了探究。用红外光谱(IR)对合成固化剂进行表征,合成的固化剂与环氧树脂乳液进行涂膜实验,通过扫描电镜(SEM)观察了涂膜层形貌,显示涂膜效果良好。深色面漆的性能测试:硬度为H,附着力达到1级,抗石子冲击为1级,耐腐蚀达3d,涂膜的透明性较好。     

无溶剂纳米SiO2改性环氧涂料的制备及涂覆建筑护栏施工要素

为了克服现有环氧树脂增韧改性时韧性增强而环氧树脂本身优异性能降低的技术难题,并解决环氧树脂的高柔韧性和无溶剂化的矛盾,先以带环氧基团的硅烷偶联剂KH-560改性纳米SiO₂,之后与液体环氧树脂E-51进行化学接枝反应,制得改性环氧树脂,再加入活性稀释剂和低黏度固化剂制备无溶剂纳米改性环氧涂料并对其配方进行优化,获得了柔韧性和防腐蚀性能俱佳的改性环氧涂料。以改性环氧涂料为底漆,以丙烯酸聚氨酯涂料作为面漆,详细介绍了复合涂层体系在不锈钢建筑护栏防护时的施工工艺和作业方法。结果表明:改性纳米SiO₂用量为环氧树脂E-51的2%³%时,纳米改性环氧涂料的柔韧性和防腐蚀性能优良;活性稀释剂用量为纳米改性环氧树脂的30%⁴0%,固化剂选用酚醛树脂固化剂NX-5198,附着力促进剂选用环氧基硅烷KH-560,用量为纳米改性环氧树脂的3%时,得到的改性环氧涂料施工、涂膜性能优良。     

茶油基水性胺类环氧固化剂的结构与性能

以茶油皂脚脂肪酸甲酯为原料制备水性胺类环氧固化剂,通过热失重分析、力学性能测试等考察了封端剂种类、n(四乙烯五胺TEPA)∶n(单环氧甲基四氢邻苯二甲酸双酯SEMeTHP-DE)、脂肪醇聚氧乙烯醚(AEO)的聚合度及n(环氧)∶n(胺氢)对涂膜性能的影响。结果表明,选择苄基缩水甘油醚为封端剂,物质的量比n(TEPA)∶n(SEMeTHP-DE)为1.2∶1,聚合度为4的AEO(AEO-4)为亲水扩链剂制备的水性胺类环氧固化剂与水性环氧乳液AB-EP-20按n(环氧):n(胺氢)之比1.2∶1进行固化时,涂膜性能最佳,此时漆膜柔韧性1mm、铅笔硬度2H、附着力1级、耐冲击性≥50 kg.cm、耐水性(25℃)≥3d、耐乙醇性(25℃)≥3d。     

环氧树脂水性化及其特性的研究

通过化学改性方法将环氧树脂E-44与油酸进行酯化反应,在与马来酸酐加成合成一种阴离子型水性环氧树脂.研究了酯化反应过程中反应温度、反应时间和酯化率的关系;探讨了反应物配比对水性环氧树脂水分散性,稳定性及固化性能的影响.利用红外光谱对产物结构进行表征.结果表明:环氧树脂E-44与油酸等摩尔比,反应温度130℃,反应时间4～5h所制得水性环氧树脂性能最好且体系不含有机溶剂.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

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.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

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.