有机蛭石/酚醛树脂熔融插层纳米复合材料的研究

用十六烷基三甲基溴化铵对膨胀蛭石进行了有机化处理,并用熔融法制备了有机蛭石/酚醛树脂插层纳米复合材料.通过XRD,AFM,TGA测试分析了所制备的复合材料的结构与热性能.结果表明:酚醛树脂能插层于蛭石片层中,制得的蛭石/酚醛树脂插层纳米复合材料的耐热性有了很大程度的提高.     

有机蛭石的制备与应用研究现状

从蛭石的晶体化学特征出发,在探讨蛭石有机改性原理的基础上,评述了有机蛭石的改性方法与特点,以及改性蛭石在环境保护和纳米复合材料方面的应用.蛭石层间阳离子的可交换特性是使有机阳离子插入到层间域的驱动力;采用胺盐和有机大分子可获得不同层间距的插层有机蛭石;有机改性蛭石可作为有机污染物的良好吸附剂,也是制备聚合物/蛭石纳米复合材料的前驱体.     

聚乳酸/蛭石纳米复合材料的原位聚合与性能研究

首次用原位聚合的方法制备了剥离型聚乳酸/蛭石纳米复合材料.以液态的单体丙交酯溶胀蛭石,然后引发单体进行聚合.XRD和TEM分析表明原位聚合法制备的纳米复合材料中蛭石片层完全剥离,分散与PLA基体中.用XRD和DSC分析和观察了聚乳酸/蛭石纳米复合材料基材的结晶性能,结果表明层状纳米蛭石聚乳酸的结晶度降低,球晶粒径大大降低.拉伸性能的考察表明制得的纳米复合材料的力学性能大大提高.     

氯丁橡胶/蒙脱石纳米复合材料的研制

以蒙脱石、氯丁橡胶为原料,采用聚合物溶液插层法研究了反应温度、时间和蒙脱石用量对制备氯丁橡胶/蒙脱石纳米复合材料的影响.以X-粉晶衍射法、透射电镜为手段研究了在氯丁橡胶基中有机蒙脱石的插层剥离行为及工艺条件.通过对样品进行分析表征,结果表明,在反应时间72h、温度65℃、蒙脱石含量为4%的条件下,可得到剥离型氯丁橡胶/蒙脱石纳米复合材料.经过混炼硫化,对改性橡胶的力学性能进行测试,结果表明,氯丁橡胶的邵尔A硬度、拉伸强度、定伸应力有明显提高.     

纳米有机蛭石/ 天然橡胶复合材料的制备及性能

以十六烷基三甲基溴化铵为插层剂, 用球磨法对蛭石进行了快速有机插层, 用过熔融共混法制备出纳米有机蛭石/ 天然橡胶复合材料。用XRD、SEM、TEM 对其微观结构进行了表征与分析, 证明蛭石以纳米片层分散在天然橡胶基体中。力学性能测试表明: 复合材料拉伸强度、扯断伸长率、300 %定伸强度、邵氏A 硬度、撕裂强度得到明显的改善。DMA、DSC 测试表明: 复合材料的模量具有明显的提高, 而玻璃化转变温度无明显变化。可见有机插层蛭石对天然橡胶的综合性能具有较明显的改善作用。      

熔融插层制备聚苯乙烯/蛭石纳米复合材料的结构与性能研究

通过熔融插层法制备了聚苯乙烯(PS)/蛭石纳米复合材料,测试了复合材料的力学性能、燃烧性能和熔体流动速率,并对不同蛭石含量的PS/蛭石纳米复合材料进行了对比。结果表明,当蛭石含量为3%时,与纯PS相比,熔体流动速率只降低了4%,即仍具有良好的加工性能,同时拉伸强度、断裂伸长率和缺口冲击强度分别提高了3.4%、77%和41%。氧指数测试结果表明,蛭石的加入有利于提高材料的阻燃性能。     

微波辅助原位聚合法制备聚乳酸/蛭石纳米复合材料

对蛭石(VMT)有机改性后,以丙交酯为单体,在催化剂存在的条件下采用微波辅助原位聚合法制备聚乳酸/蛭石(PLA/VMT)纳米复合材料。利用广角X射线粉末衍射法(WAXD)、傅立叶红外光谱法(FT-IR)以及差示扫描量热法(DSC)对材料进行了表征。对蛭石的添加量对材料的插层效果以及材料性能的影响进行了讨论。结果表明,在反应时间很短的情况下,蛭石即可以纳米尺寸分布在PLA中。随蛭石含量的不同,分别得到了剥离型和插层性PLA/VMT纳米复合材料。     

插层型蔗糖/蛭石纳米复合材料的制备

以蔗糖和蛭石为原料,在超声辅助条件下采用溶液插层法制备插层型蔗糖/蛭石纳米复合材料。X射线衍射（XRD）、红外光谱（FTIR）分析表明,蔗糖/蛭石复合物样品的d001值为1.852nm;样品的红外谱图中出现甲基和亚甲基特征峰2761cm-1和2969cm-1。将蔗糖/蛭石复合物在氮气氛下碳化后,样品的XRD（d001=1.247nm）和红外光谱结果（甲基和亚甲基特征峰2761cm-1和2969cm-1消失）表明,碳/蛭石复合材料层间夹有碳,进一步证实得到插层型蔗糖/蛭石复合材料。同时,确定了优化插层反应工艺条件,超声功率为400W,物料配比为蛭石：蔗糖=1：2.5,超声水化时间为0.5h,超声反应温度为70℃,反应时间为2.5h,静置时间2h。     

纳米蛭石改性聚丙烯薄膜的制备及其透氧性能研究

利用熔融插层法制备了纳米蛭石改性聚丙烯复合材料,测试研究了材料的结晶性能、力学性能、阻氧性能、阻湿性能和表面摩擦系数,并进行了分析。实验结果表明:添加了1%(质量分数)蛭石的改性聚丙烯材料中蛭石纳米级分散效果较好,阻氧性能得到了明显提高,与空白膜相比透氧量降低了12.89%。     

蛭石的改性——有机蛭石的碳化

以十六烷基三甲基溴化铵(CTAB)为有机试剂,通过溶液法将其插入蛭石层间,制得有机改性蛭石(O-Ver).使用X-粉晶衍射仪、差热分析仪研究蛭石、有机改性蛭石煅烧过程中的变化情况,确定碳化工艺,而后在一定条件下对O-Ver进行高温煅烧,使蛭石层间的CTAB碳化,制备碳夹层式的碳-蛭石复合材料.用所制得的碳-蛭石复合材料与天然橡胶复合制备天然橡胶/碳-蛭石复合材料.通过用高阻仪、氧指数测定仪分析测试,结果表明,天然橡胶/碳-蛭石复合材料的导电率增大,抗静电能力增强.因此,说明碳化的O-Ver改善了蛭石的电学性能,同时该材料较好地改进了橡胶的电学性能.     

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.