HDPE-g-MAH对HDPE/石墨导热复合材料性能的影响

针对高密度聚乙烯(HDPE)/石墨复合材料中石墨与HDPE的相容性差,复合材料性能较差的缺点,采用3-氨基丙基三乙氧基硅烷对石墨进行表面改性,然后以HDPE-g-MAH作为HDPE与石墨的相容剂,研究了其对HDPE/石墨导热复合材料性能的影响。结果表明,当HDPE-g-MAH用量为3%(质量分数,下同)时,HDPE/石墨复合材料的拉伸强度和冲击强度分别从未加HDPE-g-MAH时的25.0 MPa和5.9 J/m2提高到27.1 MPa和6.9 J/m2。SEM结果显示,HDPE-g-MAH改善了HDPE与石墨的界面结合情况。接触角和表面能结果进一步证明,HDPE-g-MAH改善了石墨在HDPE基体中的分散性,石墨在HDPE中的团聚减少。     

光棒废料中提取的白炭黑的疏水化改性

为找出光纤预制棒废料中提取的白炭黑的改性效果好的硅烷偶联剂,用KH-560、KH-151、KH-171、KH-602和CG-551等10种硅烷偶联剂对该白炭黑进行改性。白炭黑在140℃下活化20 h,将活化的白炭黑3 g分别与10种不同的偶联剂0.3 m L在45 m L二甲苯溶剂中130℃加热搅拌13 h,离心分离后,固体样品加适量的无水乙醇洗涤烘干后即得到改性的白炭黑。改性后样品的沉降性、亲油化度、表面羟基数等实验结果表明,10种硅烷偶联剂都能对白炭黑进行改性,其中KH-560、CG-8030、KH-151、KH-171、KH-172、KH-570对白炭黑的改性效果优于含氨基或巯基的KH-602、KH-792、CG-551、KH-550等。     

聚乳酸/木粉复合材料的力学及吸水性能研究

采用聚乳酸（PLA）及偶联剂马来酸酐（MAPP）对木粉进行改性,研究采用熔融共混方法制备的聚乳酸/木粉复合材料的力学性能、吸水性能、微观特性,以及宏观与微观之间的联系。研究结果表明力学性能方面,随着木粉含量从10g增加到25g,最大拉力增加了4倍,抗拉强度增加了3倍;偶联剂使用后,最大拉力和抗拉强度较未使用前最大增加值都超过了1倍。吸水性能方面,随着木材成分的增加,复合材料的吸水率同时增加,2和24h增重最多分别为2.85%和8.12%;偶联剂的使用降低了复合材料的吸水率,2和24h增重最多分别为0.72%和3.58%。最后使用电子扫描显微镜（SEM）观察发现同样木粉含量,添加偶联剂后界面更加光滑,PLA与木粉之间的粘合更紧密。     

废纸浆增强HDPE复合材料的力学性能

将废旧瓦楞纸板粉碎制浆,与高密度聚乙烯通过注塑成型制备废纸浆/HDPE复合材料。研究了废纸浆含量,相容剂HDPE-g-MAH和LDPE-g-GMA,加工助剂S-105、TKM-M80和Deoflow A对废纸浆/HDPE复合材料力学性能的影响,通过扫描电镜SEM分析了复合材料的冲击断面,结果表明,HDPE-g-MAH和...     

聚乙烯/杨木粉基木塑复合材料的性能研究

目的 研究硅烷偶联剂(KH-550)处理木粉以及微胶囊红磷(HP)阻燃对木塑复合材料(WPC)的性能影响.方法 以杨木粉、低密度聚乙烯(LDPE)、线性低密度聚乙烯(LLDPE)和HP为原料,采用二次共混造粒及注射模塑法,制备WPC,通过熔体流动速率(MFR)试验、拉伸试验、TGA谱图分析、Kissinger动力学分析和SEM显微观察研究WPC的性能.结果 采用KH-550处理木粉后,体系的MFR提高了0.01 g/min,拉伸时的最大位移提高了2.59 mm,HP的添加使WPC在分解5％和50％时的温度分别提高了18℃和54℃,KH-550和HP共改性的WPC在420～500℃(主要分解阶段)的表观活化能为153 kJ/mol.结论 采用KH-550处理杨木粉后,使体系的拉伸性能得到有效改善,在添加质量分数为10％的HP后,WPC的阻燃效果得到显著提高.     

聚乙二醇改性相变微胶囊制备MicroPCMs-WF/HDPE复合材料物理力学性能

以正十二烷醇（DA）为芯材,密胺树脂（MF）和聚乙二醇改性密胺（PMF）树脂为壁材制备了相变微胶囊（MicroPCMs）,并分别添加到木粉/高密度聚乙烯（WF/HDPE）复合材料中,获得了具有相变蓄热能力的MicroPCMs-WF/HDPE复合材料。采用SEM、FTIR和纳米压痕等方法对MicroPCMs的表面形态、力学性能进行了分析与表征,同时对MicroPCMs-WF/HDPE复合材料的物理力学及热性能进行了测试。结果表明:经聚乙二醇改性后,改性微胶囊（PMF-MicroPCMs）的弹性模量和硬度较未改性微胶囊（MF-MicroPCMs）分别增加了13.9%和30.0%;MicroPCMs-WF/HDPE复合材料的熔融温度区间（22.2~28.7℃）满足人体舒适温度范围,较纯WF/HDPE复合材料温度变化速率明显减缓;相比纯WF/HDPE复合材料,MicroPCMs-WF/HDPE复合材料的吸湿性、冲击强度和表面硬度增加,弯曲和拉伸性能下降;PMF-MicroPCMs-WF/HDPE复合材料的性能均优于MF-MicroPCMs-WF/HDPE复合材料,且达到了木塑装饰板材的力学性能标准要求。      

离子聚合物改性木粉/HDPE复合材料流变特性

为了提高木塑复合材料（WPC）的加工流动性能,利用离子聚合物改性WPC,通过HAAKE Minilab微量混合流变仪研究了离子聚合物改性木粉/高密度聚乙烯（HDPE）的毛细管流变特征。结果表明：添加与未添加离子聚合物的木粉/HDPE均为非牛顿流体中的假塑性流体,均呈现出“剪切变稀”的效应;随着钠离子聚合物含量的增加,改性木粉/HDPE的剪切应力和表观黏度均随着剪切速率的增大呈现降低的趋势,表明钠离子聚合物的加入可以显著改善聚合物熔体的流动特性;添加4wt%的钠离子聚合物和4wt%的锌离子聚合物的木粉/HDPE剪切应力和表观黏度均要低于添加4wt%的偶联剂马来酸酐接枝聚乙烯（MAH-g-PE）的WPC的值,表明与MAH-g-PE相比,离子聚合物更能够改善WPC的流动性能,减小熔体流动时HDPE与木粉之间的摩擦阻力;SEM分析表明,添加离子聚合物后HDPE塑料对木粉有很好的包覆效果,没有明显的界面缝隙,且在WPC断面上存在大量的毛刺纤维。     

复配偶联剂对SiO_2/聚四氟乙烯复合材料性能的影响

制备了不同组分配比的氨丙基三乙氧基硅烷(KH550)-苯基三甲氧基硅烷(Z6124)复配偶联剂(KH550-Z6124)改性SiO2/聚四氟乙烯(PTFE)复合材料,系统地研究了KH550-Z6124组分配比对复合材料介电性能、吸水率和导热性能的影响。采用Lichtenecker模型计算了SiO2/PTFE复合材料的介电常数和介电损耗理论值,并与实验值进行对比。结果表明:当KH550、Z6124的含量(以SiO2的质量为基准)分别为0.3wt%和1.7wt%时,KH550-Z6124改性SiO2/PTFE复合材料的介电损耗由Z6124改性SiO2/PTFE复合材料的1.7×10-3降低至1.0×10-3,吸水率由0.082 6wt%降低至0.020 3wt%,导热率提高66%;SEM形貌分析发现KH550-Z6124改性SiO2颗粒在PTFE基体中均匀分散,界面连接更紧密;KH550-Z6124改性SiO2/PTFE复合材料的介电常数和介电损耗实验值更接近其理论值。     

硅烷偶联剂改性的木粉/P34HB复合包装材料的制备

目的研究硅烷偶联剂KH550含量对木粉/P34HB复合包装材料性能的影响。采用KH550改性木粉,提高与聚(3-羟基丁酸酯-4-羟基丁酸酯)(P34HB)的结合强度,改善复合材料的力学性能和界面相容性。方法以KH550为改性剂,木粉和P34HB为原料,利用共混热压工艺制备改性木粉/P34HB复合材料;通过对复合材料的形貌进行观察,以及傅里叶变换红外光谱(FTIR)、热重分析(TGA)和力学性能分析,研究KH550质量分数不同时对复合材料界面相容性、力学性能和热性能的影响。结果添加KH550后,复合材料的的界面相容性得到改善;FTIR分析表明,KH550已经成功接枝到木粉中;适量的KH550提高了复合材料的热稳定性;复合材料的储能模量增加;复合材料的力学性能也有所提高。此外还得到了最佳的KH550添加量,即质量分数为0.5%。结论 KH550不仅使得木粉与P34HB的相容性得到改善,同时也增强了复合包装材料的力学性能和热性能。     

机械共混法制备改性氧化石墨烯/天然橡胶复合材料及性能表征

采用Hummers法制备氧化石墨烯(GO),用硅烷偶联剂γ―氨丙基三乙氧基硅烷(KH-550)对氧化石墨烯进行改性,得到改性氧化石墨烯(MGO),并用红外光谱、X射线衍射仪和扫描电镜对其进行表征分析。用机械共混的方法制备MGO/天然橡胶(NR)复合材料,研究了MGO/NR复合橡胶的力学性能、动态性能以及动态生热性能,并与GO/NR复合材料性能对比。结果表明,经KH-550改性后的氧化石墨烯能有效地去除部分亲水基团,改善其在天然橡胶中的分散性。随着MGO用量的增加,复合材料的力学性能有所提高,损耗因子和动态温升均有所提高,Payne效应增大。     

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.