液化MDI基形状记忆聚氨酯软段组成的选择

以液化MDI和BDO（1,4-丁二醇）为硬段,分别以聚乙二醇（PEG）,聚己二酸乙二醇酯（PEAG）,聚己二酸丁二醇酯（PBAG）,聚己二酸己二醇酯（PHAG）,聚己内酯（PCL）为软段合成了聚氨酯形状记忆材料。通过FT—IR,DSC等考察了它们的结构,比较了聚乙二醇聚氨酯（EGPU）,聚己二酸乙二醇酯聚氨酯（EAPU）,聚己二酸丁二醇酯聚氨酯（BAPU）,聚己二酸己二醇酯聚氨酯（HAPU）及聚己内酯聚氨酯（CLPU）的形状记忆性能和力学性能,研究表明,PHAG是液化MDI基形状记忆聚氨酯软段的最佳原料。     

异佛尔酮二异氰酸酯基聚醚聚氨酯弹性体的热行为

采用熔融预聚二步法合成了以环氧乙烷－四氢呋喃无规共聚醚为软段，异佛尔酮二异氰酸酯和1，4－丁二醇为硬段的热性聚氨酯弹性体，利用DSC，DMA和TG对聚合物的热行为进行了研究。结果表明，异佛尔酮二异氰酸酯基聚醚聚氨酯弹性体具有典型的微相分离特征，随着硬段含量的增加,微相分离程度增加。     

交联对透明聚氨酯弹性体结构与性能的影响

采用一步法以异佛尔酮二异氰酸酯（IPDI）、聚氧四亚甲基二醇（PTMG）、1，4－丁二醇（BD）和聚氧化丙烯三醇（N3010）为原料合成了透明聚氨酯弹性体，通过DSC、FT－IR、TG等方法研究了物理交联和化学交联对聚氨酯弹性体的力学性能、光学透明性和热稳定性的影响。结果表明，尽管聚醚二元醇的分子量增大，但由于硬段间的氢键作用增加，使微相分离程度提高，聚氨酯弹性体的力学强度增加。加入交联剂三元醇N3010，聚氨酯弹性体在硬段间形成化学交联、透度、热稳定性和力学性能与未加交联剂的聚氨酯弹性体相比有明显提高。     

以聚六亚甲基碳酸酯二醇和聚四亚甲基醚二醇为基的聚氨酯的合成…

以聚六亚甲基碳酸酯二醇（ＰＨＭＣＤ）和聚四亚甲基醚二醇（ＰＴＭＥＧ），４．４’－对二苯基甲烷二导氰酸酯（ＭＤＩ）及１．４－丁二醇（ＢＤＯ）合成线型聚碳酸酯聚氨酯，研究了其软段相的Ｔｇ，力学性能和流变特性。结果表明随ＰＨＭＣＤ含量增大，聚合物的拉伸强度增加，而熔体的表观粘度则降低。     

形状记忆聚氨酯的结构与性能研究

以 2 ,4 -甲苯二异氰酸酯 (2 ,4 -TDI)、不同分子量的聚己二酸丁二醇酯 (PBAG)和 1,4-丁二醇 (BDO)为原料合成了具有形状记忆功能的聚氨酯材料。通过DSC、弯曲实验和力学实验 ,研究了形状记忆聚氨酯的性能 ,发现软段高度结晶和硬段聚集形成硬段微区是其具有较好形状记忆性能的必要条件。     

聚碳酸丁二醇酯多孔膜的制备及亲水改性

通过热致相分离法结合双扩散法制备了聚碳酸丁二醇酯(PBC)多孔膜,并将之与聚己内酯(PCL)多孔膜进行力学性能和接触角的比较。发现PBC的接触角小于PCL多孔膜的接触角,但其力学性能不及后者。通过不同分子量的聚乙二醇(PEO)对PBC多孔膜进行改性,其亲水性进一步提高,发现分子量为2.0×105的PEO改性的多孔膜亲水性提高较大,该组膜材料降解速率与亲水性具有正相关性。     

聚丁二烯聚氨酯弹性体的微相结构与性能

用端羟基聚丁二烯齐聚物（ＨＴＰＢ）作为软段，以甲苯二异氰酸酯（ＴＤＩ），１，４－丁二醇（ＢＤＯ）作为硬段合成了聚氨酯弹性体，用ＦＴ－ＩＲ、ＷＡＸＤ、ＳＡＸＡ、ＤＳＣ和回弹性实验对聚合物的性能进行了表征。结果表明，聚合物具有微相分离的特征，硬段微区尺寸为４０×１０－１０～１００×１０－１０ｍ。受热史对聚合物的玻璃化温度有较大的影响，随着硬段含量的增加而变大。     

对苯二酚—双（β—羟乙基）醚扩链聚醚型聚氨酯的 …

分别用对苯二酚－双（β－羟乙基）醚（ＨＱＥＥ）和１,４－丁二醇（ＢＤＯ）作扩链剂,采用本体一步法合成几种不同硬段含量（０￣５０％）的二苯苛甲烷－４,４’－二异氰酸酯／聚四亚甲基醚二醇的聚醚聚氨酯,借助ＤＳＣ和ＩＲ等手段分析该聚氨酯的结晶性以及氢键行为,最后主为ＨＱＥＥ扩链聚醚型聚氨酯的微相分离程度较高,这是由其形成的硬链段刚性较强所致。     

聚酯型热塑性聚氨酯弹性体的制备及阻尼性能

以聚酯多元醇、4,4’-二苯基甲烷二异氰酸酯(MDI)和1,4-丁二醇为原料制备了一系列聚酯型热塑性聚氨酯弹性体(TPU),对硬段含量、软段种类和软段的分子量等分子结构参数对其力学性能和阻尼性能的影响进行了研究,探索影响规律性,采用原子力显微镜对其软/硬段微相分离结构进行了研究。     

碳酸乙二酯与二醇反应制备聚碳酸酯二元醇

以碳酸乙二酯、1,4-丁二醇和1,6-己二醇为原料,醋酸锌、硝酸锌为催化剂,考察了反应温度、反应时间等条件对碳酸乙二酯与二元醇反应的影响,制备出结构规整的以β-羟乙基、ω-羟烷氧基为端基的聚碳酸酯二元醇。产物经核磁共振波谱表征,1,4-丁二醇反应的聚碳酸酯二元醇的数均分子量为300-560,产物中由脱羰基反应形成的醚键链段含量可小于3%,1,6-己二醇反应的聚碳酸酯二元醇的数均分子量为700-980,产物中醚键链段含量可降低至0.24%。最后探讨了碳酸乙二酯与二元醇的反应机理。     

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.