原位聚合制备聚丙烯/蒙脱土纳米复合材料及其结构性能表征

首先制备MMT／MgCl2／TiCl4插层催化剂，并通过原位聚合的方法制得聚丙烯(PP)／蒙脱土(MMT)纳米复合材料。XRD和TEM分析结果表明，蒙脱土在聚丙烯基体中被剥离并成纳米级分散。在低于80℃左右时，PP／MMT纳米复合材料的储能模量明显高于纯聚丙烯的储能模量。PP／MMT复合材料的玻璃化温度比纯PP提高了2℃～5℃。     

有机改性蒙脱土对聚乙烯稳定性影响

用甜菜碱为有机改性剂对蒙脱土(MMT)进行有机改性,使其变为有机蒙脱土(O-MMT),并采用熔融插层法制备了聚乙烯/有机蒙脱土(PE/O-MMT)复合材料。通过特性黏度分析了不同含量有机改性蒙脱土的聚乙烯/有机蒙脱土复合材料样品膜在人工加速老化实验下的光降解特性,并采用扫描电镜分析了有机蒙脱土含量为0%和4%的聚乙烯/有机蒙脱土复合膜表面形貌。结果表明:有机改性蒙脱土(O-MMT)能有效提高聚乙烯的光降解稳定性。     

硬聚氯乙烯/蒙脱土纳米复合材料的制备与性能

以蒙脱土为主要原料，通过适宜的有机物插层荆对其改性研制有机蒙脱土。利用高聚物PVC的亲油性，且运用插层技术将聚合物熔融插入有机蒙脱土层间，将蒙脱土片层刺离出来，使之蚋米级地分散在PVC相中，从而制得硬聚氯乙烯（PVC—U）／层状硅酸盐蚋米复合管材，管材的力学性能得到了较大的改善。同时，FT—IR和XRD也证实了蒙脱土已均匀地分散在PVC基体中。此外，文中还用热重分析仪考察了复合材料的热性能，蒙脱土的加入提高了PVC的耐热等级。     

苯乙烯-N苯基马来酰亚胺共聚物/蒙脱土纳米复合材料的制备与表征

分别使用无机蒙脱土和有机蒙脱土用乳液插层的方法制备了苯乙烯-N苯基马来酰亚胺共聚物／蒙脱土纳米复合材料，并用FT-IR、XRD、DSC、TGA对其进行了表征。结果表明，两种蒙脱土在St-NP-MI共聚物基体中，均已达到纳米分散，而且复合材料的热稳定性较纯St-NPMI共聚物有很大提高，尤其是有机蒙脱土纳米复合材料，其Ta提高60℃以上。     

PP/蒙脱土纳米复合材料的制备及剪切粘度

应用双螺杆挤出机熔融插层制备出PP／蒙脱土纳米复合材料，X射线衍射表明，PP高分子链已插层进入有机蒙脱土片层之间。应用两种不同缝隙厚度的窄缝流变仪对PP及PP／蒙脱土纳米复合材料的剪切粘度及影响因素进行了研究。结果表明，PP／蒙脱土纳米复合材料为剪切变稀性流体。在190℃和210℃温度下，PP／蒙脱土纳米复合材料呈现类固体的非牛顿流体行为，剪切粘度随着剪切速率的升高逐渐降低。在230℃和剪切速率小于80s^-1的情况下，PP／蒙脱土纳米复合材料呈现类牛顿性流体行为。温度较高时,蒙脱土的含量对复合材料的剪切粘度的影响较为明显。     

煤基聚乙烯/蒙脱土复合材料的阻燃特性

研究了以聚磷酸铵(APP)、季戊四醇(PER)和三聚氰胺(MEL)复配成的膨胀型阻燃荆、煤及蒙脱土阻燃协同作用及其对煤基聚乙烯／蒙脱土复合材料阻燃性能的影响。少量蒙脱土即可显著提高聚乙烯的极限氧指数。超细煤粉的含量在一定范围内可明显提高聚乙烯／蒙脱土复合材料的极限氧指数．煤、蒙脱土及膨胀型阻燃剂之间存在良好的协同阻燃效应．可使聚乙烯的极限氧指数得到一定的提高。热氧化分解及红外光谱分析表明，煤、蒙脱土及膨胀型阻燃荆之间的协同阻燃效应与煤基聚乙烯／蒙脱土阻燃材料具有良好的热稳定性和较高的残炭率有关。     

聚乙烯/有机蒙脱土纳米复合材料结晶动力学

采用熔融插层法制备了聚乙烯/有机蒙脱土纳米复合材料,利用示差扫描量热法(DSC)研究了复合材料的等温及非等温结晶行为,并与纯聚乙稀进行了比较.通过Avrami方程,修正Avrami方程的Jeziorny法及Ozawa法分别对等温及非等温结晶过程进行了处理.结果表明:蒙脱土片层在复合材料结晶过程中起到了异相成核作用,复合材料的成核机理与生长方式已不同于聚乙烯;在相同结晶条件下,复合材料的结晶速率明显比聚乙烯快;纯PE的表观活化能为142.14 kJ/mol,而复合材料为158.38 kJ/mol,复合材料的活化能有一定程度提高;对非等温结晶过程分析,Jeziorny方法适用,而Ozawa方法不适用.     

蒙脱土填充相对蒙脱土/淀粉复合材料结构和性能的影响

利用XRD和DMTA分析手段对填充不同类型蒙脱土的蒙脱土／淀粉复合材料的结构、性能及其相互关系进行了初步研究。结果表明，蒙脱土／淀粉复合材料的性能与蒙脱土片层的无序分散程度相关。通过对有机化蒙脱土的溶胀处理，有机化蒙脱土的片层趋向于无规分散，从而也令蒙脱土／淀粉复合材料的性能大为改观。     

一锅法乳液聚合制备聚苯乙烯/蒙脱土纳米复合材料

采用一锅法乳液聚合制备了聚幕乙烯／蒙脱土(PS／MMT)蚋米复合材料．一锅法即在无机蒙脱土(Na—MMT)有机化处理后,直接将乳化剂和幕乙烯单体等加入有机蒙脱土(O—MMT)悬浮液进行乳液聚合,克服了传统方法中有机蒙脱土在乳液聚合体系中不易分散的难题。XRD谱图表明,该方法成功地实现了聚苯乙烯对蒙脱土的插层．获得了良好的插层效果(蒙脱土d001面片层间距＞4nm);FT—IR表明,PS大分子链已插层进入蒙脱土片层间;DSC显示,蒙脱土的加入使聚幕乙烯的玻璃化温度Tε由原来的99．7℃提高到107．1℃;TGA表明．插层复合提高了聚幕乙烯的热稳定性。此外,由XRD谱图还初步提出了一锅法乳液聚合的插层机理。     

硅烷交联聚乙烯/纳米蒙脱土复合材料的研究

以聚乙烯接枝马来酸酐为载体树脂制备纳米蒙脱土母料，在双螺杆挤出机中制备了硅烷交联聚乙烯／有机蒙脱土复合材料，研究了有机蒙脱土含量对硅烷交联聚乙烯接枝料力学性能、热性能以及交联料交联度的影响，并使用X射线衍射(XRD)、透射电子显微镜(TEM)研究了复合材料的微观结构。结果表明：硅烷交联聚乙烯接枝料的力学性能得到了提高，拉伸强度最大提高了近30％，断裂延伸率基本不变；维卡软化温度及热稳定性有一定提高；交联料的交联度有所下降，但可以通过延长交联时间弥补。XRD和TEM表明硅烷接枝聚乙烯大分子能够实现对有机蒙脱土的插层。     

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.