叠层法制备环氧树脂梯度交联聚合物及其性能

以α,ω-对苯甲胺基聚乙二醇、聚醚胺D400和双酚A环氧树脂(DGEBA)为原料,通过叠层法制备了玻璃化转变温度范围最大可达80℃且峰值半高宽为47.26℃的梯度聚合物材料。通过扫描电镜、拉力试验机和高级扩展流变仪研究了固化剂组分对制备的梯度交联聚合物材料结构、力学性能和阻尼性能的影响规律。结果表明,通过调整单层聚合物的交联密度即可得到适用于不同使用温度范围的宽玻璃化转变温度且力学性能优异的无微相分离结构的梯度交联聚合物材料。梯度交联聚合物tanδ>0.3的有效阻尼温域为41.54℃,且处于室温工作温度范围内。     

微交联PPG型聚氨酯弹性体的制备与性能

聚氧化丙烯多元醇(PPG)型聚氨酯弹性体具有良好的耐水解性和耐候性,但其力学性能和耐热性能不足。本工作以丙氧化季戊四醇(PPG-4,四官能度聚醚多元醇)、4,4'-二苯基甲烷二异氰酸酯(MDI)和PPG-1000为原料,合成含有交联中心的PPG型聚氨酯预聚体,以1,4-丁二醇(BDO)为扩链剂制备微交联PPG型聚氨酯预聚体弹性体。通过拉伸试验、维卡软化温度测试、动态力学性能分析(DMA)、差示扫描量热(DSC)和动态流变等手段,考察了不同PPG-4含量对PPG型聚氨酯弹性体力学性能、热性能和流变性能的影响。研究结果表明,PPG-4的加入可提高PPG型聚氨酯弹性体的拉伸强度、撕裂强度和硬度;微交联PPG型聚氨酯预聚体弹性体的耐热性能显著提升,其维卡软化温度由90℃(PPG-4含量为0%)提高至135℃(PPG-4占PPG-1000含量的3%);DSC与DMA结果表明,微交联PPG型聚氨酯预聚体弹性体的玻璃化转变温度明显提高;流变测试表明,PPG型聚氨酯弹性体的弹性模量、粘性模量和复数黏度均显著提高。     

不同交联层厚度的聚丙烯酸酯乳液的制备及压敏性能

通过调控增长阶段交联剂参与反应的时间,采用半连续种子乳液聚合方法制备了一系列固含量为50%,乳胶粒粒径相同但交联层厚度不同的聚丙烯酸酯乳液。采用动态光散射、凝胶渗透色谱和动态力学热分析等手段,考察了交联层厚度对乳液聚合过程、聚合物分子结构及分子运动的影响。结果表明,交联层厚度对聚合过程和乳液稳定性没有明显影响;随着交联层厚度的增加,聚合物的凝胶含量和储能模量增加,可溶部分相对分子质量和缠结相对分子质量减小。依据FINAT标准测试了该乳液压敏胶的初黏力、剥离力和耐持黏性。控制交联层厚度在合适范围,可得到压敏性能均衡的乳液。     

交联改性阴离子聚氨酯水分散体的制备与性能研究

由甲苯二异氰酸酯（TDI）、聚己内酯二醇（PCL）和二羟甲基丙酸（DMPA）反应,再与高醚化度甲醇醚化三聚氰胺甲醛树脂（HMMM）反应,制备了一种交联型阴离子水性聚氨酯。采用红外光谱对样品进行表征,并讨论了交联改性对聚氨酯乳液粒径分布、胶膜耐水性、力学性能、热稳定性及结晶度的影响。红外分析证实HMMM与聚氨酯发生了交联反应。当m（HMMM）∶m（—COOH）=2.25时,胶膜拉伸强度达到30.3MPa,吸水率为17.2%,吸乙醇率为10.9%,与水接触角为69.6°,Tmax（最快分解温度）为301.5℃,结晶度为1.10%。     

交联型聚醚聚氨酯的表征、力学性能及其碱金属盐络合物的导电性能

采用三羟甲基丙烷（ＴＭＰ）作交联剂与聚乙二醇（ＰＥＯ－１５４０）和甲苯二异氰酸酯（ＴＤＩ）反应，得到了具有较好力学性能的交联型聚醚聚氨酯（ＰＥＵ），该聚合物与ＬｉＣｌＯ４的结合物具有较高的室温电导率（σ３０℃＝１．８７×１０￣（－４）Ｓ／ｃｍ）。采用全反射红外光谱（ＡＴＲ－ＩＲ）对聚合物的结构进行了表征。对聚合物的组成、不同ＴＤＩ类型及络合盐浓度对聚合物力学性能及其络合物电导率的影响进行了探讨。低度交联聚合物的络合物，其电导率与温度的关系符合建立在自由体积理论上的ＶＴＦ方程，表明络合物中离子的传导主要是在无定形区域进行，与自由体积有关。     

含碳癸硼烷交联聚氨酯弹性体的合成及热性能

以1,2-二(4′-羟基苯基)邻碳癸硼烷、甲苯二异氰酸酯(TDI)三聚体和端羟基聚丁二烯为原料,采用两步法合成了一种新型的含碳癸硼烷结构的交联聚氨酯弹性体。通过研究催化剂用量、预聚时间、反应物浓度等对交联聚氨酯凝胶率的影响,确定了交联聚氨酯的合成条件,在TDI三聚体质量分数为32%、催化剂用量为0.1%和预聚时间为4h的条件下,可得到具有较高凝胶率的交联产物。利用热分析技术研究了在氩气气氛下,交联聚氨酯从室温至800℃的热性能。研究发现,含5.3%碳癸硼烷聚氨酯第1阶段最快降解速率对应温度比普通聚氨酯提高了53℃,800℃的残余率提高了16.7%。     

双重可逆交联互穿网络聚合物的制备与表征

以三联吡啶修饰聚己内酯(PCL-Tpy)、蒽修饰聚四氢呋喃(PTMEG-An)制备得到2种线型结构聚氨酯,混合后向其中先加入金属离子再施加紫外辐照形成热可逆的三联吡啶-金属离子配位键与光可逆的双蒽环加成2种交联,制备出双重可逆交联的动态互穿网络(IPN)聚氨酯,利用核磁共振与红外光谱对交联剂和预交联聚合物的化学结构进行表征。紫外-可见吸收光谱、差示扫描量热分析(DSC)与凝胶含量测试表明,蒽交联聚合物随辐照时间加长交联度增加;DSC的测试结果表明,Zn~(2+),Sn~(2+)与Ni~(2+)作为配位中心交联强度与可逆温度区间不同;IPN样品中两相均成形成了交联网络。表征结果表明,设计制备的该IPN样品结构在紫外光与热的多重刺激下分子结构可实现由线型到Semi-IPN以及IPN的可逆转变,两相交联性能容易调控。     

高温拉伸制备交联聚乙烯微孔膜的探索研究

采用热拉伸-高温退火-冷拉的拉伸工艺制备了交联聚乙烯微孔膜,考察了交联聚乙烯的交联度、拉伸温度、退火温度和冷拉等工艺条件对交联聚乙烯微孔膜成孔性能的影响,并对成孔过程和机理进行了探讨.交联聚乙烯的交联度显著影响成孔性能,随着交联度的增加,成孔性增加.拉伸温度在90～120℃时,膜片基本由纤维状晶构成.拉伸温度升至130℃,并在此温度进行高温退火处理,膜片开始出现细缝状微孔.施加冷拉可以调控细缝状微孔形态演变,进一步被拉伸成圆形或椭圆洞状微孔.本文所用拉伸工艺为制备高性能聚乙烯微孔膜提供了一种新的思路,有助于开发自主知识产权的聚乙烯微孔膜技术,突破锂离子电池隔膜等高端聚乙烯微孔膜的国外技术垄断.     

基于吡啶盐的热固性交联聚氨酯的合成与非线性光学性质的研究

合成了双芪唑盐的衍生物,双四苯硼（反式）－4,4′－二[p-（（N－乙基－N－羟乙基）氨基）苯乙烯基]-N,N′－（1,6－己基）－二吡啶盐。该生色团与2,4－二异氰酸酯甲苯及三乙醇胺反应生成了交联的聚氨酯体系。Marker条纹法测得聚合物的二阶非线性系数d33为12．5pm/V。利用紫外－可见光谱吸收法测定了聚合物薄膜电晕极化后的生色团取向度,考察了在室温及100℃的取向稳定性。结果表明在100℃放置1200h序参数为0．46,保持为初始的65％。用双脂数函数拟合了聚合物的退极化曲线。     

用介电方法研究COPU/PMMA交联共聚物的转变与松弛

用TRS-10C型介电损耗仪,在不同频率,-180℃～170℃范围内测得COPU/PMMA交联共聚物的介电损耗谱。计算了各松弛过程的活化能,考察了组成和交联密度对分子运动、相容性及形态结构的影响。结果表明,COPU/PMMA交联共聚物是个半相容体系,其相容性随PMMA含量的增加和交联密度的减小而变坏。介电损耗谱上的次级松弛是COPU链段运动的贡献。界面极化区松弛谱的各点温度和频率的关系符合Arrhenius方程,各点温度和其高温侧松弛曲线线性部分斜率的大小可以反映相容性的好坏。     

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.……     

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.