ABS/多层石墨烯纳米复合材料性能研究

利用双螺杆挤出制备了ABS/多层石墨烯(GNPs)纳米复合材料并研究了其性能。结果表明,GNPs的加入一定程度上提高了ABS的杨氏模量和弯曲模量,但冲击强度有明显的降低。GNPs加入较少时能有效地提高ABS的耐热性能,GNPs含量为2%时,维卡软化点提高8.4℃;GNPs加入更多反而使ABS的维卡软化点温度降低。冲击断面SEM和DSC分析表明,GNPs主要分散于SAN相中。     

聚氯乙烯/粘土纳米复合材料的制备及性能

通过原位插层法制备了聚氯乙烯／粘土纳米复合材料，分别采用X射线衍射，透射电子显微镜对其结构与形态进行了表征。结果表明，粘土片层已基本被刺离，均匀分散于聚氯乙烯树脂基体中。复合材料的力学性能和耐热性能测试结果表明，适量有机粘土的加入能使其拉伸强度和维卡软化点均较纯聚氯乙烯有较大提高。     

邻甲酚醛树脂/邻甲酚醛环氧/氧化石墨烯复合材料

为改进酚醛固化环氧树脂复合材料的性能,合成了邻甲苯酚醛树脂(o-CFR)、邻甲酚醛环氧树脂(o-CFER)和氧化石墨烯(GO),制备了o-CFR/o-CFER/GO玻璃钢复合材料,研究了不同含量的氧化石墨烯对复合材料物理力学性能的影响。结果表明,GO加入可以改善材料的力学性能、耐热性能和电绝缘性能。当酚醛与环氧质量比为4∶6,材料中加入1.2%的GO时,起始分解温度(Tid)提高了91℃,复合材料的拉伸强度和冲击强度分别提高了102%和86%;加入2.0%时材料玻璃化转变温度(Tg)可提高19℃。     

纳米 TiO 2/聚乳酸复合材料的制备和表征

采用原位聚合的方法制备了有机化处理过的纳米 TiO 2粒子质量分数分别为 1 wt %、3 wt %、5 wt %和10 wt %的 4种纳米 TiO 2/聚乳酸复合材料。SEM结果表明 , 当纳米 TiO 2粒子质量分数较低时 , 纳米 TiO 2在聚乳酸基体中呈现均匀稳定分散 , 而质量分数较高时则发生团聚。通过力学和热学等性能测试发现复合材料的最大热分解温度、 玻璃化转变温度和力学性能相对于聚乳酸有较大幅度提高 , 其中纳米 TiO 2的质量分数为 3 wt %时改善效果最明显 , 其最大热分解温度、 玻璃化转变温度分别比聚乳酸提高了 25. 3℃和 4. 9℃, 拉伸强度、 断裂伸长率和弹性模量分别提高了 83. 6 %、 6. 73 %和 129. 4 %。     

石墨烯-多壁碳纳米管协同增强环氧树脂复合材料的低温力学性能

为了提高环氧树脂的低温力学性能,采用石墨烯与多壁碳纳米管(MWCNTs)协同改性环氧树脂,系统研究了石墨烯-MWCNTs/环氧树脂复合材料的室温(RT)和低温(77K)力学性能。结果表明:当石墨烯的质量分数为0.1wt%,MWCNTs的质量分数为0.5wt%时,纳米填料的加入可同时改善环氧树脂的低温拉伸强度、弹性模量和冲击强度;在此最佳含量下,石墨烯-MWCNTs/环氧树脂复合材料在RT和77K时的拉伸强度皆达到最大值,比纯环氧树脂的拉伸强度分别提高了11.04%和43.78%。石墨烯和MWCNTs能协同提高环氧树脂的低温力学性能。     

迈科烯/乙烯-醋酸乙烯共聚物纳米复合材料的制备及性能

迈科烯是兼具优异导电性与亲水性的新兴二维纳米材料,将其与加工性能好、柔韧性高的弹性体结合制备纳米复合材料是实现柔性功能材料的热门研究方向之一。首先采用氟化钠NaF/浓盐酸HCl水热法制备迈科烯Ti_3C_2T_X,然后用溶液混合法制备了不同比例的Ti_3C_2T_X/EVA(乙烯-醋酸乙烯共聚物)纳米复合材料。采用差示扫描量热仪、维卡软化点测试仪和热重分析仪探究了Ti_3C_2T_X/EVA纳米复合材料的热学性能,数据表明随着Ti_3C_2T_X质量分数的增加,Ti_3C_2T_X/EVA纳米复合材料的熔融温度、结晶温度、维卡软化点温度、最大热失重温度都比纯乙烯-醋酸乙烯共聚物(EVA)高,说明了加入Ti_3C_2T_X提高了EVA的耐热性;使用万能拉力实验机研究了复合材料的力学性能,结果显示随着Ti_3C_2T_X含量的增加,复合材料的拉伸强度、断裂伸长率、弹性模量均呈现出先增大后减小的趋势,说明适量的Ti_3C_2T_X可以提高EVA的力学性能。     

含稀土的N-环己基马来酰亚胺耐热改性剂在PVC中的应用

用乳液聚合的方法制备了马来酸单十二酯镧-N-环己基马来酰亚胺-丙烯腈-甲基丙烯酸甲酯四元共聚物,将其作为耐热改性剂与PVC共混。研究了马来酸单十二酯镧的用量对共聚物组成、PVC的热性能和力学性能的影响。结果表明,LaTM用量为20%(文中物质含量均为质量百分数)时,共聚物用量为PVC的20%时,共混物的维卡软化点比纯PVC的提高了1.6℃,热分解温度Td50比纯PVC提高了12.33℃,拉伸强度、冲击强度均明显提高。     

石墨烯/低密度聚乙烯复合膜的制备及性能

目的以石墨烯/低密度聚乙烯(LDPE)复合包装材料为研究对象,讨论石墨烯、石墨烯微片对低密度聚乙烯薄膜力学性能、颜色、透光率及透氧率的影响。方法使用熔融共混方法制备不同石墨烯质量分数的石墨烯/LDPE复合材料,检测并比较其性能变化。结果石墨烯以及石墨烯微片的加入,使LDPE薄膜的弹性模量提高了9%~50%,横纵向拉伸强度提高了2%~30%,透光率降低了10%~60%,透氧率提高了10%~15%。结论由于石墨烯比表面积大、刚性高,对LDPE材料的拉伸强度、弹性模量等力学性能有明显改善,同时可提高薄膜透氧率,加深LDPE材料的颜色,降低薄膜透光率。     

共混法制备耐热型ABS树脂研究

通过共混法制备了AS树脂与ABS胶粉的合金以及不同种类ABS树脂之间的共混合金,测试了合金的力学性能和耐热性能,通过配方设计制得了维卡软化点温度分别满足95,100,105,110℃的四个等级的耐热型ABS树脂,维卡软化点温度最高可以达到114.6℃,并且其抗冲击性能优良.     

PBS/SiO2纳米复合材料的制备及其结构与性能分析

以聚丁二醇丁二酸酯（PBS）为基材,经-甲基丙烯酰氧基丙基三甲氧基硅烷偶联剂（KH570）改性过的纳米SiO2和未改性的SiO2为填料,采用熔融共混法制备了PBS/SiO2纳米复合材料。研究了所得纳米复合材料的热稳定性能、力学性能和降解性能等。结果表明：当经KH570表面改性的纳米SiO2（KH570与纳米SiO2的质量之比为1：5）的添加质量分数为4%时,复合材料的维卡软化点约提高了10℃,拉伸强度约提高30%,同时复合材料的降解性能比PBS纯料的降解性能有一定的提高。     

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.