β-成核剂对聚丙烯/木粉复合材料结晶与力学性能的影响

通过挤出成型法制备聚丙烯/木粉复合材料(PP/WF),添加一种镧系稀土金属络合物(WBG)成核剂诱导PP/WF复合材料中等规聚丙烯(iPP)形成β晶型。以差示扫描量热和X射线衍射为表征方法,分析成核剂对PP/WF结晶行为的作用,进而研究其对力学性能的影响。结果表明,WBG成核剂能有效地诱导PP/WF产生β-iPP结晶,当WBG的添加量为m(WBG)/m(PP)=0.3/100时其产生的β晶相对含量达到78.75%,β-iPP的相对含量还与PP/WF的冷却速率密切相关;添加WBG提高了复合材料中iPP的结晶温度;WBG成核剂能显著改善复合材料的冲击韧性,但对弯曲和拉伸性能略有不利影响。     

钛化合物对聚丙烯力学性能和结晶形态的影响

用对叔丁基苯甲酸和钛酸四异丙酯合成了两种聚丙烯成核剂TiD3和TiD4。利用热重分析(TG)考察了成核剂的热稳定性,利用X射线衍射(XRD)、差示扫描量热(DSC)和偏光电子显微镜(PLM)对PP/TiD3、PP/TiD4的结晶行为和晶体形态进行了考察,并考察了PP/TiD3、PP/TiD4的力学性能。结果表明,TiD3、TiD4是有效的α-成核剂,能明显提高PP结晶速率和结晶度,结晶温度分别提高了10℃和12.1℃,PP的力学性能显著提高,当TiD4的添加量为0.3%(质量分数,下同)时,PP的拉伸强度和抗弯曲强度分别提高了5.32MPa和12.1MPa。     

纳米SiO_2及硅溶胶成核剂对透明聚丙烯结构与性能的影响

利用偏光显微镜、光电雾度仪、差热分析(DSC)及力学性能测试分别考察了成核剂纳米SiO2(Nano-SiO2)和硅溶胶(Si sols)对均聚聚丙烯(PP)透明性、结晶性能及力学性能的影响。研究结果表明,由于在PP基体中有更好的分散性,在相同添加量下,硅溶胶的异相成核效果比纳米SiO2明显。在成核剂质量分数达到0.15%时,PP材料的透明性最好;在成核剂加入量为0.05%时,PP材料的冲击强度及拉伸强度均达到最大值。     

有机磷酸酯盐与羧酸盐复配成核剂对等规聚丙烯性能的影响

以2,2'-亚甲基-双-（4,6-二叔丁基苯基）磷酸钠 （NA-11）和双环[2,2,1]-庚烷-2,3-二羧酸钠 （NA-CA）2种成核剂进行复配,研究复配成核剂对等规聚丙烯（iPP）力学性能和结晶行为的影响。采用双螺杆挤出机为共混设备将成核剂与iPP共混,制备了NA-11/NA-CA/iPP复合材料。通过万能材料实验机、XRD、DSC、偏光显微镜（PLM）对其力学性能、结晶形态、微观结构进行了表征。结果表明:NA-11和NA-CA 2种成核剂复配能够显著提高iPP的拉伸性能和弯曲性能。NA-11和NA-CA复配成核剂诱导iPP形成α晶体。2种成核剂1∶1复配,添加量为0.4wt%时,iPP的结晶峰温度提高了20.3 ℃,结晶度提高了8.8%。PLM显示,NA-11和NA-CA复配成核剂使iPP球晶尺寸明显变小。NA-11和NA-CA复配成核剂具有很好的成核效果,这2种成核剂对改善聚丙烯的结晶性能和力学性能具有协同效应。      

用热差法研究成核剂对PET结晶性能的影响

通过溶液法制样,采用DSC测试方法测试了成核剂添加种类和添加量不同的PET树脂的结晶行为。结果表明:加入碘化钠、滑石粉、碳酸钠成核剂可以提高PET树脂的结晶性能,具体表现为提高PET的结晶温度和缩短其结晶时间,其中碘化钠成核剂的效果最为明显,滑石粉作为成核剂的效果不理想。由于成核剂和树脂相容性和溶液法残留的溶剂的影响,成核剂添加量对改善PET结晶性能的影响并不明显。     

聚丙烯包装材料透明改性的研究

目的以均聚聚丙烯为研究对象,研究具有更好透明度的聚丙烯材料的配方。方法使用直接加入法对各种原材料进行配比,在单螺杆挤出机进行共混熔融挤出造粒,根据测试标准进行制样并测试。结果添加质量分数为0.3%的α成核剂到均聚聚丙烯中时,聚丙烯试样的熔融温度最高,结晶度最大,半结晶时间最短,透光率和拉伸强度最大,冲击强度最小。结论在均聚聚丙烯中添加质量分数为0.3%的α成核剂复配助剂可以制备耐150℃以下的温度,且具有更好透明度的聚丙烯材料。     

口服液瓶用聚丙烯包装材料的改性研究

通过添加成核剂改善口服液瓶用聚丙烯(PP)材料的耐热性能与力学性能,研究了成核剂种类与用量对PP性能的影响.结果表明:α晶型成核剂C可以有效提高PP热变形温度、透明性、刚性、拉伸强度及弯曲强度;β晶型成核剂B可以有效提高PP热变形温度、冲击强度;成核剂的加入使得PP结晶温度提高;改性的PP材料经注射吹瓶,可以满足PP口服液瓶灌封后蒸汽灭菌要求,且α晶型成核剂C改性PP的水蒸汽渗透性低于未改性PP.     

稀土β成核剂含量对PPR性能与结晶行为的影响

选用新型稀土β成核剂(WBGⅡ)对无规共聚聚丙烯(PPR)进行改性。借助广角X射线衍射(WAXD)、差示扫描量热仪(DSC)及偏光显微镜(POM)研究了稀土β成核剂诱导无规共聚聚丙烯的结晶行为及晶体形态;并研究了WBGⅡ对PPR力学性能和热变形温度(HDT)的影响。结果表明,加入少量WBGⅡ后,PPR的晶型和结晶形态均发生变化;非等温结晶过程的结晶温度(Tc)从95.8℃提高到102.1℃;PPR的冲击强度提高24%,拉伸和弯曲性能却略有下降;热变形温度提高20℃。     

聚乳酸/癸二酸二苯基二酰肼的制备及其性能

为改善聚乳酸（PLA）的结晶性能,以癸二酸二苯基二酰肼（TMC）为成核剂,采用熔融共混法制备PLA/TMC共混物,研究成核剂TMC的含量对聚乳酸结晶性能、热性能及力学性能的影响。结果表明,成核剂TMC对PLA有良好的异相成核作用,纯PLA在以10 ℃/min的速率降温过程中没有结晶峰,而添加成核剂TMC后,PLA有明显的结晶峰,并且随着TMC含量的增加,PLA的冷结晶温度从117.03 ℃降低至110.60 ℃。成核剂的加入使得PLA球晶密度增加且尺寸减小。当添加TMC的质量分数为0.8%时,PLA的断裂伸长率提高了26.4%。     

有机磷类成核剂作用下聚丙烯结晶行为及其力学性能

研究了含有不同含量成核剂的聚丙烯的结晶行为对其力学性能的影响．结果表明，当成核剂含量从0增至0．8％(质量)时，树脂的拉伸强度和弯曲强度提高了15％，弯曲模量增加了35％，结晶温度提高了10℃，由非线性Volterra积分方程得到的成核密度提高了10^4倍，而且成核聚丙烯的成核密度与其材料的力学性能之间存在着线性关系，即随着成核密度的增大，材料的拉伸和弯曲性能呈线性的增大．     

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.