聚二甲基硅氧烷-梯形苯基倍半硅氧烷共聚物的制备

探讨了用羟基硅油(PDMS)和苯基三甲氧基硅烷(PTMS)合成聚二甲基硅氧烷-梯形苯基倍半硅氧烷共聚物的反应条件,通过IR、1H-NMR确定了目标产物的结构.     

聚苯基倍半硅氧烷研究进展

分别介绍了梯型、笼形聚苯基倍半硅氧烷及其共聚物的结构、性质和合成方法,重点综述了苯基倍半硅氧烷共聚物研究进展,并对苯基倍半硅氧烷材料的发展趋势进行了展望。     

梯形聚苯基倍半硅氧烷的新型制备方法

以苯基三氯硅烷为原料,利用经过改良的热平衡缩合法,得到产物梯形聚苯基倍半硅氧烷(Ph-T)。借助傅立叶红外、X射线衍射和核磁共振硅谱等方法,确定了产物具有规整的梯形分子结构;以热重分析测定了其耐热性,在空气中失重5%时温度为530℃,具有优良的耐热性能。     

巯基-苯基聚倍半硅氧烷的合成

以巯丙基三甲氧基硅烷和苯基三甲氧基硅烷为原料,在甲醇作溶剂、浓HCl作催化剂的条件下水解缩合制备了巯基聚倍半硅氧烷和巯基-苯基聚倍半硅氧烷,并利用FTIR和GPC对合成产物进行了表征。结果表明:当苯基单体添加量为20%时,所制备的巯基-苯基聚倍半硅氧烷中均含有一定量的巯基和苯基,在引入部分苯环增加折光率的同时也保持了产物拥有进一步反应的活性巯基,且相对分子质量较大,分子量分布较窄。     

梯形聚苯基倍半硅氧烷／聚甲基丙烯酸甲酯溶液浇注共 …

用溶液浇注法制备了具有不同质量配比的高分子量，低分子量梯形聚苯基倍半硅氧烷与聚甲基丙烯酸甲酯的共混物。用扭辫分析技术研究了不同分子量ＰＰＳＱ与ＰＭＭＱ间的相容性及热历史对其相容性的影响。     

笼型倍半硅氧烷的合成与应用

笼型倍半硅氧烷(POSS)是一种新型有机硅杂化材料,在耐高温材料、阻燃材料以及高分子增强材料方面具有广阔的发展前景.主要介绍了苯基、氨基、环氧基和甲基等4种官能团取代笼型倍半硅氧烷的合成方法及影响因素、性能和应用前景.     

桥联聚倍半硅氧烷纳米带的制备

依照文献以L-丙氨酸为手性源合成了一阴离子型两亲小分子化合物,利用圆二色谱研究了该化合物在水中的自组装行为,同时通过溶胶-凝胶复制法,以该手性阴离子型两亲小分子化合物的自组装体作为模板,以(3-胺丙基)三甲氧基硅为结构助剂,以倍半硅氧烷为硅源制备了桥联聚倍半硅氧烷纳米带,并利用扫描电镜、透射电镜和圆二色谱方法研究了该纳米带结构。透射电镜和圆二色谱表征结果表明,1,4-亚苯基桥联聚倍半硅氧烷和4,4′-亚联苯基桥联聚倍半硅氧烷的结构为中间有间隙的双层纳米带,且在纳米和埃的尺度下具有手性。     

一种聚苯基甲基硅氧烷改性环氧树脂耐高温防腐蚀涂料的制备研究

采用苯基三甲氧基硅烷和苯基甲基二甲氧基硅烷水解合成了聚苯基甲基硅氧烷(PS),然后改性E-20环氧树脂,通过环氧值、红外光谱分析表明,有机硅接枝了环氧树脂且环氧基保持不变。用DSC、TGA分析了有机硅含量对改性树脂固化体系耐热性能的影响,当m(E-20)∶m(PS)=100∶25时,化学改性树脂固化体系的耐热性能明显提高。以此改性树脂为基料,采用适宜的固化剂,添加适当的颜料、功能填料、助剂等制备耐高温防腐蚀涂料。结果表明,该涂料不仅具有优异的常规涂膜性能,同时还具有优异的耐高温及防腐蚀性能。     

超支化有机硅树脂的制备、改性及其应用

综述了以ABn(n=2,3,4)型单体制备超支化聚碳硅烷、超支化聚碳硅氧烷和超支化聚烷氧基硅烷三类超支化有机硅树脂的合成工艺及其改性技术,重点介绍了制备含不饱和双键和环氧基团的功能性超支化有机硅树脂单体的分子设计与制备技术。论述了超支化有机硅树脂在薄膜材料、复合催化剂、增强助剂等领域的应用研究进展。     

新型反应性硅氧烷

日本大阪市立工业研究所有机硅树脂研究室采用非传统的制备方法开发了新型反应性硅氧烷——双(羟苯基)二硅氧烷和双(烯丙氧基苯基)二硅氧烷。前者具有与双酚A相类似的结构,可望用作合成聚酯、聚碳酸酯、环氧树脂的改性剂;后者可以用作特种共聚用单体和交联剂。有机硅树脂所具有的可挠性、耐热性、耐寒性、耐候性、耐氧化性、透氧性、耐氧等离子性、消泡性、生理惰性、疏水性、剥离性等表面特性以及溶解性等等,莫不源于聚硅氧烷各种特异的物性。为了将这些优异特性引入其他聚合物,已开发了采用①硅烷偶联剂;②单端反应性硅氧烷低聚体;③双     

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.     

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 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.……     

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.……     

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.     

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.     

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.