耐高低温环氧有机硅胶粘剂的力学性能研究

介绍了一种研制的室温固化、耐高温、耐低温环氧有机硅胶粘剂。通过对胶粘剂的剪切强度分析,探讨了原料配比,偶联剂等因素对环氧有机硅胶粘剂力学性能的影响。研究表明:增韧剂在胶粘剂中含量适当时(质量比25%),能与固化剂充分反应,有机硅与环氧树脂也能获得较好的相溶性,制备的环氧有机硅胶粘剂的综合性能较优;硅烷偶联剂能改善胶膜界面层的胶接强度,提高环氧有机硅胶粘剂的剪切强度。     

固化剂对聚酰亚胺挠性覆铜板剥离强度的影响

采用双氰胺(DICY)、间苯二胺(m-PDA)、长链柔性二胺(DAMI)固化双酚A型环氧树脂(E-51),制备了三种环氧胶粘剂,分别考察了三种固化剂对挠性覆铜板剥离强度的影响。根据差示扫描量热仪(DSC)曲线,通过t-β外推法得到了各固化剂固化环氧胶粘剂的固化工艺。采用扫描电子显微镜(SEM)考察其不同的破坏形式。结果表明,采用双氰胺固化的环氧胶粘剂粘接的挠性覆铜板,剥离后聚酰亚胺薄膜、铜箔表面都留有大量的胶粘剂,此破坏形式属于内聚破坏。同时双氰胺固化的环氧胶粘剂剥离强度最高,粘接强度达到0.74 N/mm,符合日本JPAC行业标准。     

自修复环氧胶粘剂分子设计

在自修复聚合物复合材料中,修复剂黏度和高聚物强度是保证自修复过程实现的重要因素。文中以合成用于自修复材料的环氧树脂微胶囊为目的,在双酚A型环氧树脂(E-51)中加入稀释剂正丁基缩水甘油醚(BGE)降低黏度,采用傅里叶红外(FT-IR)分析稀释剂对环氧胶粘剂与微胶囊咪唑类固化剂交联反应的影响,表征了在固化过程中稀释剂参与环氧胶粘剂与咪唑类固化剂的交联反应;使用差示扫描量热(DSC)技术对该固化反应进行动力学研究,确定出稀释剂的最佳用量;通过拉伸实验测定了环氧树脂固化产物的强度,表明BGE的加入增强了环氧树脂的胶粘性能。     

LCD/OLED用紫外光固化胶粘剂研究进展

紫外光(UV)固化环氧丙烯酸胶粘剂粘结强度高、化学稳定性好、电学性能优良、耐热性好,特别适合LCD/OLED的封装.介绍了UV固化环氧丙烯酸胶粘剂的国内外生产、研究进展,提出了混杂固化、可循环使用和水性化是其发展趋势.     

新型室温固化双组分胶粘剂的研究

利用自合成聚丙烯酸酯聚合物和环氧丙烯酸酯制备了新型双组分室温固化丙烯酸酯胶粘剂.研究并讨论了该胶粘剂组成的比例、活性单体对粘合强度、胶粘性能和胶粘剂的贮存稳定性的影响、确定了室温固化氧化-还原体系剂及适宜固化时间用量.该胶粘剂对金属的拉伸强度可达23.5MPa.     

一种耐高温聚酰亚胺胶粘剂的合成

以醚胺(ODA)、砜胺(DDS)和醚酐(ODPA)、酮酐(BTDA)为原料,采用冷却法和加热法分别合成了一种耐高温聚酰亚胺胶粘剂。通过搭接试验和聚酰亚胺膜结构表征,比较了两种不同合成方法所得聚酰亚胺胶粘剂的性能差异。通过试验选择了亚胺胶的搭接工艺和固化工艺,从而使聚酰亚胺胶粘剂的粘接性能达到最佳。     

端氨基聚氨酯的合成及增韧环氧树脂的研究

合成了数均分子量(M^-n)不同的聚乙二醇型端氨基聚氨酯(ATPU2)。并用它与E-44环氧树脂配成了综合力学性能好的胶粘荆。用DSC、FT—IR、SEM分别表征了ATPU2／E-44胶粘剂的固化过程、固化产物的结构以及冲击断面形貌,测试了胶粘荆的柔韧性、附着力和剥离强度等力学性能与ATPU结构的关系。结果表明,ATPU2/E-44胶粘剂的中温固化主要是通过端氨基与环氧基反应完成的;它具有的冲击强度高等优异的力学性能与其固化后的交联网络形成了一种由环氧刚性链段和柔性聚乙二醇链段组成的两相结构和产生断裂时能形成微纤结构密切相关。     

膜组件浇铸用室温固化环氧树脂耐热胶粘剂的研究

针对耐高温膜组件的浇铸,研制了可室温固化环氧树脂耐热胶粘剂.探讨了环氧树脂、固化剂的种类以及固化剂和稀释剂添加量对胶粘剂性能的影响.考察了胶粘剂的粘接性能,并通过差示量热扫描仪(DSC)分析了固化反应过程中的放热情况及固化产物的耐热性.结果表明:双酚F树脂与A105固化剂配制的胶粘剂耐热性好,黏度低,粘接性能优良,当固化剂质量分数为28%时,固化物的玻璃化温度Tg可达91℃.     

聚氨酯胶粘剂固化反应对其流变性能的影响

利用HAAKE旋转流变仪研究了双组分聚氨酯胶粘剂的流变性质及固化过程中不同结构聚氨酯胶粘剂的凝胶时间与固化活化能,并通过差示扫描量热法(DSC)研究了样品的固化过程,分析了固化过程对胶粘剂流变性质的影响。通过Arrhenius公式推导得到聚氨酯胶粘剂的交联活化能。结果表明,预聚物的游离二苯基甲烷二异氰酸酯(MDI)含量越高、或分子量越高,聚合物的流体强度越强,固化反应速度越快,凝胶时间越短;提高固化温度可以促进交联反应的进行,缩短凝胶时间。     

有机硅改性环氧丙烯酸预聚物的合成和UV固化膜性能

以四丁基溴化铵为催化剂,对苯二酚为阻聚荆,环氧树脂和甲基丙烯酸以及乙烯基三乙氧基硅氧烷为原料,合成有机硅改性的环氧丙烯酸光敏预聚物.分析了合成反应机理,讨论了反应时间、反应温度、阻聚剂用量对反应的影响.用红外光谱表征了合成产物的结构.将合成的光敏预聚物配制成光固化胶粘剂固化,测定了固化膜的硬度和柔韧性.结果表明:在环氧丙烯酸聚合物中含有C=C双键和Si-O-Si键;反应温度为90～100℃,对苯二酚阻聚荆的加入量为0.3%(质量分数),合成反应时间4.5h;光固化膜的铅笔硬度为5H,柔韧性良好,膜层光洁.     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

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.     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

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.