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。     

环氧大豆油改性水性聚氨酯胶粘剂

以聚氧化丙烯二醇、甲苯二异氰酸酯等为原料,以环氧大豆油为改性剂制备出环氧大豆油改性聚氨酯乳液,以该乳液配制出复合软包装膜用水性聚氨酯胶粘剂.用傅立叶变换红外光谱和粒度分析仪对乳液进行了表征,考察了聚氨酯乳液的稳定性及其胶膜的耐水性,研究了水性聚氨酯胶粘剂对几种复合薄膜的粘接性能.红外分析表明,环氧大豆油中的环氧基发生反应,形成了环氧大豆油改性水性聚氨酯.当环氧大豆油用量为4%～6%(质量分数,后同),聚氨酯乳液的稳定性较好,粘度较小,胶膜的吸水率不高,以该乳液配制的胶粘剂可满足复合软包装膜对粘接的要求.     

环氧-聚氨酯复合乳液的合成及表征

以甲苯二异氰酸酯(TDI-80)、聚醚二醇(N220)、二羟甲基丙酸(DMPA)、环氧树脂为主要原料,合成了环氧-聚氨酯复合乳液。主要讨论了环氧树脂对水性聚氨酯乳液及其涂膜性能的影响。实验结果表明,环氧-聚氨酯乳液的表面张力、粘度,涂膜的硬度、耐水性及力学性能随着环氧树脂用量的增大而增强,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%。采用傅里叶变换红外光谱、粒径分析仪、凝胶渗透色谱(GPC)、透射电镜(TEM)对乳液和涂膜进行了表征。傅里叶变换红外光谱分析表明,环氧树脂的环氧基和羟基都参与了反应。粒径分析仪和凝胶渗透色谱分析显示,加入环氧树脂后,水性聚氨酯(WPU)分散体粒径和分子量增大,粒径分布和分子量分布均变宽。     

硅烷改性水性聚氨酯表面施胶剂的制备与性能研究

以甲苯二异氰酸酯、混合多元醇为基本原料,N-甲基二乙醇胺为亲水扩链剂,有机硅为改性剂,通过醋酸中和反应制备出一种可用于纸张表面施胶的自乳化阳离子水性聚氨酯乳液;研究了硅烷用量、预聚温度、R值(体系中异氰酸酯基和羧基的摩尔比)、聚酯＼聚醚质量比对乳液性能和施胶效果的影响.结果表明:硅烷用量为4.5％,预聚温度为60℃,R值为1.10,聚酯＼聚醚质量比为3.6时制备的乳液性能良好;FT-IR分析表明有机硅烷已通过化学方法结合到聚氨酯分子链中;TGA分析表明有机硅的加入对水性聚氨酯耐热性有明显提高;粒径分析表明,有机硅的加入能使乳液粒子分布更均匀且粒径更小;施胶效果表明水性聚氨酯对改善纸张强度作用明显,有机硅烷的加入能显著提高纸张的施胶度.     

油脂基聚氨酯改性脂肪胺水性环氧固化剂的结构与性能

以甲苯2,4-二异氰酸酯(TDI)、高级脂肪醇聚氧乙烯醚(AEO-6)、四乙烯五胺、丙烯腈为原料合成了油脂基聚氨酯改性脂肪胺水性环氧固化剂(CA-B)。将CA-B分别与水性环氧乳液AB-EP-20、AB-EP-44、AB-EP-51组成固化体系,经分析可知,水性体系CA-B/AB-EP-44性能最优。通过差示扫描量热法、涂膜力学性能测试,研究了n(环氧基)∶n(胺氢)对CA-B/AB-EP-44体系固化物性能的影响,结果表明,n(环氧基)∶n(胺氢)为1.1∶1(摩尔比)时涂膜的综合性能最佳,此时漆膜柔韧性达1 mm、铅笔硬度达2 H、附着力达1级、耐冲击性≥60 kg.cm、乙醇渗透量(%(24 h))为15.3,与参比样Ⅰ、参比样Ⅱ(市售)固化物的物理性能相当。     

环氧树脂改性水性聚氨酯胶粘剂的性能研究

通过丙酮法合成了一系列在软、硬段均含有离子基的水性聚氨酯分散液,采用共混法重点研究了环氧值,环氧树脂加入量以及R值(NCO/OH比)和离子基含量对水性聚氨酯乳液性能和胶粘剂粘接性能的影响。结果表明:选择E-44具有最佳的工艺和性能平衡,当E-44含量为3(wt%,质量分数),R值为1.3和离子基含量为1.15(wt%,质量分数)时所合成粘合剂的乳液稳定性,耐热性能和最佳的粘合性能。     

丙烯酸酯软硬单体含量对PU/PA复合乳液及其表面施胶性能的影响

采用原位无皂乳液聚合法制备了水性聚氨酯-丙烯酸酯(WPUA)复合乳液。分析了软硬单体比例对WPUA乳液粒径、粘度,对胶膜的凝胶率、吸水率和力学性能的影响,并研究了WPUA乳液对纸张的增强作用。研究表明,随着m(MMA)增大,胶粒粒径增大,乳液粘度下降,胶膜凝胶率上升,吸水率先下降后上升,且当m(MMA)为14.37%时,胶膜力学性能最佳。以质量分数为1%的WPUA乳液进行表面施胶,施胶度达37.47s,湿强度达31.61%。当m(MMA)为8.64%时,耐折度达54次。     

环氧改性水性聚氨酯的合成及因素分析

用异佛尔酮二异氰酸酯(IPDI)、聚丙二醇2000(PPG2000)、2,2-双(羟甲基)丙酸(DMPA)为主要原料合成预聚体,环氧树脂(E44)开环合成环氧改性水性聚氨酯(EWPU),考察了不同影响因素对EWPU乳液及胶膜性能的影响。首先,通过FT-IR证实了环氧改性水性聚氨酯的合成;然后,经过TG测试证明了改性后水性聚氨酯耐热性能优于水性聚氨酯;最后详细探究了DMPA量、—NCO与—OH的摩尔比(R值)、硬单体配比以及环氧量对EWPU乳液粒径、贮存稳定性、涂膜耐水性、涂膜耐磨性和力学性能的影响。结果表明,当DMPA量为5%、R值为1.5、硬单体配比为35%、EP量为8%时,EWPU乳液的综合性能最优。     

环氧大豆油改性水性聚氨酯的制备及性能表征

用二乙醇胺按照不同比例将环氧大豆油中的部分环氧基开环,然后以不同的添加量引入到水性聚氨酯链段中,合成出环氧大豆油改性的水性聚氨酯乳液。通过FT-IR表征及改性前后性能比较,表明部分开环的环氧大豆油是以化学键和的方式接入到聚氨酯分子链段中的。性能测试结果显示:经环氧大豆油改性的乳液的粒径变大,储存稳定性略有下降;改性后胶膜的拉伸强度增加,断裂伸长率下降,耐热性有提高。     

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.     

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.