光油用聚乙二醇型聚氨酯丙烯酸酯聚合物的合成

本文以2,4-甲苯二异氰酸酯(TD)、聚乙二醇(PEG)为主要原料合成了聚乙二醇型聚氨酯,再通过二羟甲基丙酸(DMPA)进行扩链,最后采用甲基丙烯酸羟乙酯(HEMA)对端基异氰酸酯进行酯化封端,合成了聚乙二醇型聚氨酯丙烯酸酯(PUA)树脂。通过调整反应温度、时间和反应物配比优化了合成工艺,对聚合物结构、分子量、粒度分布进行了表征。结果表明,按分子结构的设计要求合成得到了PUA聚合物,分子量约为26800 g/mol,分子量分布为1.26,水溶液中分散粒度尺寸在20～50μm范围内,主要集中在30μm,聚合物分散粒度均匀,分散状态稳定,有利于光油在纸品表面的涂覆。     

环氧类扩链剂的合成及对回收PET的扩链效果

采用悬浮聚合方法合成了环氧类扩链剂苯乙烯-EMC的共聚物SMC,并对其进行红外分析表征。SMC中含有活性环氧基团,可与回收PET链端的羧基反应,将其用于PET(聚对苯二甲酸乙二醇酯)的反应共混,能够大大提高回收PET的分子量,特性黏度从0.448 dL/g提高至0.57 dL/g,羧基含量减少至很低,扩链效果显著。DSC分析扩链后的PET其固有性能保持不变。这种共聚物可作为PET的扩链剂使用。     

端羧基聚苯乙烯的合成及室温缩聚

采用链式聚合方法,用4,4'-偶氮-二(4-氰基戊酸)为引发剂引发苯乙烯的自由基聚合,合成了两端带有羧基基团的功能化聚苯乙烯。研究了单体、引发剂、溶剂之间的配比及聚合温度对合成端羧基聚苯乙烯的影响。并用合成得到的端羧基聚苯乙烯与聚乙二醇在室温、常压等十分温和的条件下进行酯化缩聚反应,得到聚苯乙烯/聚乙二醇两亲性嵌段共聚物。红外分析(FT-IR)和核磁共振(~1H-NMR)测试结果证实成功合成了端羧基聚苯乙烯和聚苯乙烯/聚乙二醇嵌段共聚物;凝胶渗透色谱(GPC)和差热分析(DSC)测试结果分别表明合成得到的端羧基聚苯乙烯的分子量较大、分子量分布比较均匀,并且随着分子量的增加,端羧基聚苯乙烯的玻璃化转变温度逐渐升高。     

扩链剂对水性聚氨酯树脂性能的影响

通过马来酸酐与多元反应形成羧基酯多元醇,然后再与其他的单体和ＴＤＩ－８０、交联剂以及扩链剂等反应,制备了含羧基的聚氨酯预聚体,将其分散于三乙醇胺的水溶液中,制备了水性聚氨酯,并对扩链剂的种类和用量对树脂性能的影响进行了研究,发现氨基扩链剂比羟基扩链剂更有利于提高树脂的力学性能,但是乳液的粒径比较大。     

软段结构对聚氨酯-聚丙烯酸酯复合乳液乳胶粒形态结构的影响

为了探讨聚氨酯水分散液(WPU)的软段结构对聚氨酯-聚丙烯酸酯复合乳液(PUA)乳胶粒子形貌结构的影响,首先分别合成了不同软段结构的WPU,然后以其为种子乳液并滴加溶有引发剂的丙烯酸酯混合单体形成预乳液,升温聚合后得到PUA。通过对乳胶粒径测试和形貌观察发现,软段分子量较小时,形成的PUA乳胶粒没有明显的核/壳结构,软段分子量较大时,形成过渡层型、梯度型和草莓型结构的核/壳结构PUA乳胶粒,采用两种分子量的软段共混得到的PUA乳胶粒具有复杂的核/壳结构。     

PLA—PEG共聚物的合成与性能研究

采用熔融缩聚法合成一定分子量的聚乳酸（PLA）,并用聚乙二醇（PEG）的聚氨酯预聚体进行扩链。研究了扩链反应条件对产物分子量的影响及产物的热性能。结果表明,扩链反应后PLA的分子量有大幅度提高,且扩链前后的PLA都具有良好的热稳定性。     

聚氨酯/聚丙烯酸酯复合乳液胶束的粒径及形态

以水性聚氨酯PU为种子,加入丙烯酸酯单体进行无皂乳液聚合,合成了聚氨酯/聚丙烯酸酯(PUA)复合乳液.动态激光光散射的测试结果表明,PU分散液和PUA复合乳液的粒径大小,与聚氨酯制备过程中的亲水性扩链剂的用量有密切关系.当扩链剂用量为7.5%时, PU/PA配比对PUA复合乳液粒子的粒径大小及分布影响不大,但是PUA复合乳液的平均粒径比纯PU乳液的粒子粒径显著增大,说明形成了核壳结构.并用透射电镜进行了证实.     

改性淀粉/聚氨酯复合微球的合成与性能研究

采用超声改性法制备改性淀粉,通过预聚-扩链-中和-分散法合成聚氨酯水溶液,并用相分离法制备出超声改性淀粉/聚氨酯复合微球。考察了R值[n(—NCO)/n(—OH)]、改性淀粉的含量、聚乙二醇的分子量及固含量对复合微球形态的影响。研究了载药复合微球在体外的药物释放规律。并通过扫描电子显微镜和傅里叶变换红外光谱对微球的表面及剖面结构和化学组成进行了表征。结果表明:复合微球合成的最佳条件:R值为3,改性淀粉含量为6%(wt,质量分数,下同),聚乙二醇分子量为200,固含量为38%;复合微球表面光滑并且内部有很多致密的孔道,且聚氨酯和改性淀粉之间通过氢键连接,稳定性良好;降解性及药物释放研究显示,该类微球适于充当药物载体。     

丙烯酸改性水性聚氨酯的制备与表征

以聚乙二醇、二羟甲基丙酸(DMPA)、甲苯二异氰酸酯(TDI)为基本原料,合成了水性聚氨酯(PU)预聚体,并在此基础上加入适量丙烯酸,制备出丙烯酸改性水性聚氨酯(PUA)。对所得产物进行了表征与测试,同时,探讨了丙烯酸含量对水性聚氨酯性能的影响。研究结果表明:丙烯酸成功地接枝到水性聚氨酯分子链上,改性后的水性聚氨酯的耐热性能提高;随着丙烯酸体积分数的增加,PUA的断裂伸长率减小,拉伸强度和吸水率显著提高。     

聚氨酯-丙烯酸酯-苯乙烯复合水分散液的粒径及形态

采用原位乳液聚合法制备了水性聚氨酯-丙烯酸酯-苯乙烯(WPUAS)复合水分散液,研究了NCO/OH摩尔比、PU预聚物/MMA/ST质量比、羧基含量及羧基中和度对分散液粒子尺寸及形态的影响。结果表明,NCO/OH摩尔比减小、羧基含量增大及羧基中和度提高,都会导致分散液粒径减小;PU/(MMA+ST)质量比越小,粒径越大,粒子形态越不规整;MMA/ST质量比的变化对粒径影响不明显。     

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.     

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.     

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.     

Early ironwork in Biscay: Survey,excavation, experimentation and materials characterization. An integral study of the mountainside ironworks (ferrerías de monte or “haizeolak”)

ABSTRACT

The production of iron in Biscay (Basque Country, Spain) has been a hallmark of this territory of the North of the Iberian Peninsula throughout its history. The Archaeology team of the Basque Country Mining Museum has spent 13 years, so far, studying the origins of this activity through the evidences left at the old pre-hydraulic iron production workshops known as mountainside ironworks (ferrerías de monte) or haizeolak. It has catalogued 170 archaeometallurgical sites of this type in Biscay, and the archeological excavation of some of them has led to the knowledge of the different stages of the production process that took place in these workshops. The team has also experimentally reproduced the work carried out in a mountainside ironworks from the High Middle Ages, and it has currently started the characterization process of this type of activity through the study of the collected materials.     

Mechanism Study on the Wear of CrAlTiN Coated High-Speed Steel Twist Drills Under Dry Cutting Conditions

As demands about environment protection are growing up, dry cutting technology is getting more and more concerns from all over the world. Main works performed here are study on dry cutting performances and wear mechanisms of M2high-speed steel (HSS) twist drills with CrAlTiN multicomponent coatings, which was deposited using magnetron sputter ion plating system, in drilling 45 and 30CrMnSiA steel, and their comparisons to those in drilling the same steel but using monolayer CrN and commercial TiN coated drills. Drilling performances of drills are evaluated mainly through the measurements of width on outer corner flank land and the cutting forces. Results show that performances of CrAlTiN coated drills are better than those of monolayer CrN and TiN coated drills. In drilling 45 and 30CrMnSiA steel, the average tool life of the CrAlTiN coated drills are 17.2 and 11.8 times higher than those of the uncoated drills. Observing wear of the drill with scanning electronic microscope, results show that there is no crack or spallation of the CrAlTiN coatings in wear zones. Main mechanism of the wear here is adhesion.     

Study on Bond Ability of Arc-Spraying Coatings with Different Surface Pretreatment on Cast-Iron

Arc spraying coatings are widely used in various applications, but uncommon in cast iron substrate. Different surface pretreatment technology is tested on substrates of gray cast iron. Surface roughness and residual stress were measured by TR200 and X-ray diffraction analyzer. Influence of different surface pretreatment methods ( dry blasting and fusebond) on roughness and residual stress was analyzed. The arc-sprayed coatings of wire 3Cr13 (φ2mm) on gray cast iron substrate is studied. The microstructure and interface of bonding layer were observed by SEM. The bond strength was taken by tensile test. Results show that bond strength with grit blasting is higher than fuse-bond; it is feasible to make wire 3Cr13 coating with arc spraying on cast iron substrate roughened by grit blasting.     

Structural Characteristics of TiO2 Ceramic Coating by Micro-Plasma Oxidation

TiO2 ceramic coatings with thickness of 20 μm were formed on the surface of pure titanium by micro-plasma oxidation. Their micro-structures were investigated by by using X-ray diffraction and their surface images were detected by using scan electronic microscope. There were three kinds of TiO2 coatings, pure anatase type TiO2 phase, mixed phases consisted of rutile type TiO2 phase and anatase type TiO2 phase, pure rutile type TiO2 phase. The coating surface with the pure anatase type TiO2 phase is rough, while the coating surface with the pure rutile type TiO2phase is smooth. The upper coating surface with the mixed type TiO2 phases is anatase type TiO2 structure and the subsurface of the TiO2 coating is rutile type TiO2structure.     

Evaluation of fatigue life of steel using steel grain size

The insightful discussion of the relationship between the construction of metallographic and fatigue life and proposition of mathematical relationships describing this relationship was conducted in the paper. This paper presents a method for estimating the fatigue life, based on the construction of the microstructural material taking into account the grain size and the participation of ferrite and pearlite phase.