聚醚砜和聚醚醚酮

商品牌号为 Victrex~(R)的聚醚砜(PES)是典型的工程塑料,其韧性高、强度大、刚性强,具有极好的耐高温性能,且可燃性低,发烟少。PES 可制造线圈架、连结器、终端部件、热水表、医用聚合物涂料等。但 PES是无定形塑料,具有无定形树脂的特性。聚醚醚酮(PEEK)是结晶性耐高温工程塑料,使用温度可达300℃,其机械强度和耐化学腐蚀性能超过 PES。1.加工过程PES 和 PEEK 可用常规的设备进行模压、注射、挤出等加工,并可回收利用。加工时间与其它常规工程塑料相近。加工前都     

聚醚醚酮的合成与表征

以二苯砜为溶剂,在无水碳酸钾/碳酸钠的催化下,通过对苯二酚与4,4-二氟二苯甲酮进行亲核取代反应,合成了特性黏度为0.89的聚醚醚酮(PEEK);探讨了溶剂与反应温度对分子量的影响.通过IR、DSC、TG和XRD对其结构与性能进行了表征,确定其结构为PEEK;TG测试表明,在N2气氛下开始分解温度为541℃,且到1200℃时也没分解完全;DSC和XRD衍射图表明其为半晶态聚合物,且由DSC曲线可知其熔点(Tm)为347℃.     

甲基取代杂萘联苯型聚芳醚的合成、表征及性能

以自制的新型甲基取代类双酚 4 - ( 3-甲基 - 4 -羟基苯基 ) - 2 - 3-二氮杂萘 - 1-酮 ( OM- HPPZ)为单体与4 ,4′-二氟二苯酮、4 ,4′-二氯二苯砜进行亲核缩聚反应 ,制得了一类新型甲基取代聚芳醚酮、聚芳醚砜及其共聚物聚芳醚砜酮树脂。在适宜的聚合条件下 ,获得了高分子量的聚合物 ,聚醚酮的特性粘度可达0 .70× 10 2 m L/ g;通过调节砜酮比例 ( S/ K)可获得不同分子量、不同玻璃化温度的共聚物 ( PPESK)。利用 DSC、TGA研究了聚合物的耐热性能 ,结果表明 ,新型聚芳醚玻璃化温度高 ( 2 5 2℃～ 2 90℃ ) ,耐热稳定性好 ( 5 %热失重温度高于 4 16℃ ) ,在氯仿、DMAc等极性有机溶剂中可溶解成膜 ,以 FT- IR和 1H-NMR研究了类双酚单体 OM- HPPZ和聚合物的结构 ,证明与设计结构完全一致     

含PDMS聚砜膜的制备及其对CO_2/CH_4分离性能的影响

选用聚二甲基硅氧烷(PDMS 4200)、六氟双酚A及4,4-二氟二苯砜作为单体,通过缩聚反应制备了PDMS 4200含量为5%(摩尔分数,以下同)和10%的共聚物[聚砜(PSF)-PDMS]膜,利用核磁共振氢谱仪和傅里叶变换红外光谱仪对共聚物结构进行了表征。考察了PDMS 4200含量(0~10%)、温度(298~328K)对CO_2和甲烷气体渗透性能的影响。     

P(MMA-MAh)基凝胶聚合物电解质导锂离子性能研究

以甲基丙烯酸甲酯(MMA)和马来酸酐(MAh)单体合成共聚物P(MMA-MAh),并以其为聚合物基体制备了凝胶聚合物电解质。采用傅里叶红外光谱(FT-IR)、差示扫描量热法(DSC)和热失重分析(TGA)对合成共聚物进行了表征,并采用交流阻抗法对制备的凝胶聚合物电解质(GPE)的导锂离子性能作了研究,并且分析了不同温度和配比对其离子电导率的影响。结果表明:成功合成了聚合物P(MMA-MAh),其热分解温度为300℃,玻璃化转变温度为133.9℃,制备的GPE的离子电导率随温度的升高而增大,随聚合物含量的增加而减小,且在研究温度范围内锂离子迁移符合Arrhenius方程。     

几种甲基取代的新型可溶性聚芳醚酮醚砜醚酮的合成与表征

在无水A lC l3及DM F存在下,将4,4′-二(4-氯甲酰苯氧基)二苯砜(SPC l)、4,4′-二(3-氯甲酰苯氧基)二苯砜(SM C l)分别与2-甲基二苯醚(o-M DPE)和3-甲基二苯醚(m-M DPE)在1,2-二氯乙烷中进行低温溶液缩聚,合成了4种新型可溶性的甲基取代聚芳醚酮醚砜醚酮(M-PEKESEK)。DSC,TG,FT-IR及W AXD等测试表明,4种聚合物均为无定型结构,其玻璃化转变温度(Tg)介于157℃~167℃,在氮气气氛中5%的热失重温度(Td)均在465℃以上,易溶于氯仿和DM F、DM SO等强极性非质子有机溶剂中。     

含磷环氧树脂固化剂的合成表征与环氧树脂复合材料阻燃性能的研究

以季戊四醇(PER)、三氯氧磷(POCl_3)和乙二胺(EDA)为原料合成了一种阻燃固化剂聚乙二胺季戊四醇螺磷酸酯(PES),并通过红外光谱(FT-IR),核磁共振(1 H NMR)、质谱(ESI-MS)和热重分析(TGA)对其结构和热性能进行了表征。并以PES和4,4-二氨基二苯砜(DDS)为固化剂,双酚A型环氧树脂(E-51)为基体树脂,制备了不同含磷量的阻燃环氧树脂复合材料。通过极限氧指数(LOI)和垂直燃烧(UL-94)实验表征了环氧树脂复合的阻燃性能,热重分析和扫描电镜研究了阻燃环氧树脂的热性能和残炭形貌。研究发现,随着磷含量增加,阻燃环氧树脂的初始分解温度逐渐降低,但与纯样相比,在600℃时的残炭量显著增加,且随着PES加入量的增大,SEM观察形成的炭层越致密。当磷含量为3.48%时,其LOI值可达28.9,并通过UL-94V0级测试,拉伸强度和冲击强度分别达到了62.76 MPa和6.81kJ/m~2,表明PES是一种良好的环氧树脂阻燃剂。     

磺化聚砜膜材料的制备与性能研究

磺化聚砜是制备亲水性滤膜的优良材料。首先以发烟硫酸为溶剂、4,4’-二氯二苯砜(DCDPS)为原料成功制备了磺化单体3,3’-二磺酸钠-4,4’-二氯二苯砜(SDCDPS),并确定了最佳磺化条件,n(SO3)/n(DCDPS)=3.5,反应温度110℃,反应时间20h。以SDCDPS为单体通过亲核缩聚反应合成了一系列不同磺化度的磺化聚砜膜材料,利用红外光谱及核磁共振光谱对其结构进行了表征。热分析实验表明,该聚合物材料具有较高的分子量和热稳定性。     

PEKS分子结构及其合成的动力学研究

测定两种共单体的相对活性(γ)和两种共单体的单位含量(C_R、C_S),可定量评价聚醚酮砜二元共缩聚的非均一性。发现二氯二苯砜(DDS)与二氟二苯酮(DFK)的相对活性为1.97×10~(-08)exp(9.6×10~3/T。由~(13)C-NMR测定了C_R、C_S。PEKS的链结构按不同的三个部分(P_(RR)、P_(RS)、P_(SS))的平均链段长度值(L_R、L_S)来表征说明。 在不同反应温度及共单体的不同比例,采用~(13)C-NMR和DSC研究了合成的一系列PEKS的微观非均一性,并指出共单体和反应温度对链结构影响很大,由T_(?)温度变化能看到链结构对T_(?)的直接影响。     

聚芳硫醚砜酰胺共聚物的常压合成与表征

以自制的4,4′-二氟二苯酰胺和4,4′-二氯二苯砜及精制工业硫化钠为反应单体,在N-甲基吡咯烷酮中采用分批投料、逐步聚合的方式,进行常压缩聚,合成了线型较高分子量的新型聚芳硫醚砜酰胺共聚物(PA SS/A),在较优的反应的条件下,制得了特性黏数在0.25 dL/g~0.40 dL/g的共聚物。用红外和核磁对聚合物进行了结构表征,用TG、DSC等手段对聚合物热性能进行了测试,用XRD对聚集态结构进行了表征。结果表明,共聚物具有优良的耐热性和局部有序结构;且发现该聚合物的玻璃化温度和热稳定性随着酰胺含量的增加而略微降低。     

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.