环氧树脂改性水性聚氨酯乳液的制备研究

传统的单一聚氨酯乳液存在耐水性和耐热性较差的缺点，目前最有效的方法是对其进行改性，以增强聚氨酯乳液胶粘剂的性能，使其应用更加广泛。控制异氰酸酯指数(R值)为3.5,以聚丙二醇(PPG1000)和甲苯二异氰酸酯(TDI)为主要原料合成聚氨酯预聚体，使用环氧树脂对聚氨酯乳液进行改性。用控制变量法将不同环氧值的环氧树脂和不同添加量的环氧树脂分别作为2个变量，讨论2个变量对乳液及胶膜性能的影响，按照相关标准对其性能进行了测试与表征。结果表明：在相同用量下，环氧树脂E-44的改性效果好于其他类型环氧树脂，E-44添加量为15%(质量分数)时，制备的改性材料性能最佳。     

水性聚氨酯/聚乙烯醇复合表面施胶剂在特种纸上的应用

以聚己内酯二元醇(PCL,Mn=1000)、甲苯二异氰酸酯(TDI)和二羟甲基丙酸(DMPA)为原料,采用自乳化法制备水性聚氨酯(WPU)乳液,并用此聚氨酯乳液与聚乙烯醇(PVA)以及外加交联剂氮丙啶进行复配制得WPU/PVA复合乳液。实验研究了m(WPU)/m(PVA)对复合乳液性能及纸张表面性能的影响。研究表明,当复合乳液中WPU含量为75%,此WPU/PVA复合乳液具有优异的表面施胶性能,纸张耐折度达到1 025次,干湿强度分别为162.3,57.4N,施胶度达到97s。并通过红外光谱(FT-IR)、动态激光光散射法(DLS)及热重分析(TGA)对聚合物进行了表征。     

水性聚氨酯/聚脲乳液的制备及对纸张的表面处理

以聚己内酯二元醇为软段、异佛尔酮二异氰酸酯和二乙烯三胺扩链剂为硬段合成了水性聚氨酯乳液,研究了聚氨酯乳液对纸张的表面施胶性能,并优化了实验合成工艺。研究表明,当n(NCO)/n(OH)=1.6,w(DMPA)=3.4%,w(DETA)=0.5%时,此水性聚氨酯/聚脲乳液具有优异的表面施胶性能。以质量分数为1%的聚氨酯进行表面施胶时,施胶度达74s,湿强度达36.02%,耐折度达125次,并通过红外光谱(FT-IR),热重分析(TG)及扫描电镜(SEM)对聚合物结构及膜性能进行了表征。FT-IR表明,扩链剂的加入使聚合物形成了聚脲结构,使膜的韧性得到提高,TG表明,经扩链剂改性的聚氨酯乳液具有优良的热稳定性,SEM表明经聚氨酯乳液施胶后的纸张表面纤维间的界面变得模糊,纸张表面的纤维结合更加紧密。     

非铵盐型PUA乳液接枝PVC复合树脂的制备与表征

采用聚乙二醇单甲醚(MPEG)、异氟尔酮二异氰酸酯(IPDI)和甲基丙烯酸β-羟乙酯(HEMA)合成混合单体。然后与丙烯酸丁酯(BA)反应,通过乳液聚合的方法合成了聚氨酯-丙烯酸酯(PUA)复合乳液。以此为种子进行氯乙烯(VC)原位接枝乳液共聚,制造出了一种新型的PUA/PVC复合树脂。采用透射电镜(TEM)、动态力学分析仪、扫描电镜(SEM)等手段对PUA/PVC乳胶粒的形态、乳液PUA动态力学性能以及材料的断面形貌进行了研究。     

环氧树脂改性水性聚氨酯的合成研究

采用甲苯二异氰酸酯(TDI-80)、聚醚二醇(N220)、二羟甲基丙酸(DMPA)、环氧树脂和丙烯酸羟丙酯(HPA),合成了环氧改性的双键封端水性聚氨酯乳液.乳液由于含有不饱和双键而具有感光性能,故此乳液可用作水性紫外光固化涂料或胶粘剂的预聚物.实验结果表明,随着环氧树脂用量的增大,涂膜的硬度、耐水性、耐溶剂性及力学性能增强,但乳液外观和稳定性变差,故适宜的环氧树脂添加量为4%～8%.通过傅立叶变换红外光谱、粒径分析仪、凝胶渗透色谱(GPC)和透射电镜(TEM)等对乳液进行了表征.粒径分析仪分析显示,加入环氧树脂后,水性聚氨酯(WPU)分散体粒径增大,粒径分布变宽.凝胶渗透色谱分析表明环氧树脂改性水性聚氨酯提高了聚氨酯的分子量.     

高性能UV固化聚氨酯的制备及性能研究

选用二羟甲基丙酸(DMPA)、六亚甲基二异氰酸酯(HDI)三聚体、异佛尔酮二异氰酸酯(IPDI)、季戊四醇三丙烯酸酯(PETA)、三乙胺等为主要原料合成了高性能UV固化水性聚氨酯乳液,并在添加光引发剂1173后,UV固化制备涂层。采用FT-IR、1H NMR、TGA和DSC等对合成树脂的结构和性能进行表征。与市售水性UV固化聚氨酯乳液对比,本乳液具有更小的粒径、更高的活性,所制备的涂层具有更高的硬度、更优异的耐磨和耐水等性能。     

缩聚物/加聚物复合胶乳的制备科学Ⅱ.核壳结构聚氨酯-丙烯酸酯复合乳液的合成与表征

用合成的含羧基端羟基聚氨酯树脂，通过强外力乳化可形成稳定的水性聚氨酯乳液，与苯乙烯和丙烯酸丁酯等单体共聚，合成具有核壳结构的聚氨酯－丙烯酸酯接枝乳液，通过接枝乳液和共混乳液的性能差别对比，及DSC，FT－IR，粒径分析及力学性能测试分析表明，在聚氨酯－丙烯酸酯接枝乳液中，聚氨酯与丙烯酸酯发生部分交联形成稳定的核－壳结构，文中还对聚氨酯－丙烯酸酯接枝乳液的交联机理进行了研究。     

一种聚氨酯型高分子染料的制备及皮革涂层着色性能研究

用2,4-甲苯二异氰酸酯(TDI)、聚丙二醇1000(PPG-1000)和2,2-二羟甲基丙酸(DMPA)合成聚氨酯聚合体,再用酸性红B染料进行封端,制备了一种聚氨酯型高分子染料。通过傅立叶红外光谱对其结构进行了表征,并测定了这种聚氨酯型染料分散乳液的粒径分布,最后对坯革进行着色涂饰实验。结果表明,用含单羟基活性基团的酸性红B染料对端异氰酸酯大分子进行封端处理,能够实现染料与聚氨酯大分子的结合,可以衍生制得聚氨酯型高分子染料;在制备反应过程中,预聚反应最佳R比值为3∶1,聚合反应体系总R值为1.1,这种聚氨酯型大分子染料乳液分散体系的粒径主要分布在80～160μm之间;采用聚氨酯染料作为着色材料对坯革表面进行涂饰操作,其坯革涂层耐干湿擦色牢度、耐洗色牢度和耐色迁移性的色牢度极佳,均达到了5级,均明显高于酸性红B染料的着色涂层。     

可逆聚氨酯乳液的制备与研究

以甲苯二异氰酸酯与二官能度及三官能度的聚氧化丙烯二醇为原料,合成了乳胶粒子内分子结构分别为线型及三维网状的聚氨酯乳液,将两种乳液室温干燥成膜后,在搅拌下再进行分散乳化,通过丁达尔现象及透射电镜结果表明:前者不能通过二次分散乳化得到乳液;后者可以通过二次分散乳化再次得到乳液,成功制备了可逆聚氨酯乳液。并对这种乳液成膜及再分散乳化的机理(可逆机理)进行了初步研究。     

聚氨酯-含氟丙烯酸酯防水防油性复合乳液的制备及性能

以自乳化自交联的阳离子水性聚氨酯乳液(PU)为种子乳液进行含氟丙烯酸酯(FA)、苯乙烯(St)和丙烯酸丁酯 (BA)等乙烯基单体的自由基共聚合,制得阳离子聚氛醋-含氟丙烯酸酯(FPUA)复合乳液.通过红外光谱分析、接触角测试、表面自由能计算、粒径及粒径分布测试及透射电镜测试对聚合物乳液及其膜结构与性能进行了表征.结果表...     

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.