吐温-20的改性及其表面活性研究

以羟基硅油和吐温-20为原料合成了羟基硅油改性的吐温-20表面活性剂.采用化学分析方法、红外光谱、凝胶渗透色谱法等手段对改性的吐温-20表面活性剂结构进行了表征,研究了其水溶液的表面张力等性能.发现改性吐温-20表面活性剂的数均分子量(Mn=3808.2)是羟基硅油(Mn=1019.4)和吐温-20(Mn=1895.3)数均分子量之和.获得的羟基硅油改性的吐温-20表面活性剂在22℃时的l临界胶束浓度(CMC)约为0.02g/mL.     

羟基硅油改性聚氨酯多元醇水分散体的合成与性能

以甲苯二异氰酸酯(TDI)、聚醚多元醇(N220)、羟基硅油和二羟甲基丙酸(DMPA)等为主要原料,二乙醇胺(DEA)为封端剂引入羟基,合成了羟基硅油改性聚氨酯多元醇水分散体。采用红外光谱、核磁共振氢谱对聚合物结构进行了表征,同时研究了羟基硅油含量对聚合物乳液的粒径、黏度、稳定性以及胶膜的耐水性、耐油污性、力学性能、热性能的影响。结果表明,随着羟基硅油含量的增加,乳液的粒径和水接触角增大,黏度降低,胶膜的拉伸强度和吸水率下降,断裂伸长率升高。当羟基硅油含量为3%时,胶膜的综合性能最佳,此时其乳液粒径为92.4nm,胶膜的水接触角为93°,拉伸强度为5.5 MPa,断裂伸长率为621%,24h吸水率为7.6%。     

有机硅改性聚氨酯胶粘剂的研究

目的合成一种抗水性良好的无溶剂聚氨酯胶粘剂。方法采用聚酯多元醇(PBA)、异佛尔酮二异氰酸酯(IPDI)、蓖麻油和羟基硅油为原料,合成出一系列有机硅改性聚氨酯胶粘剂,并用红外光谱分析仪、热重分析仪对反应产物进行分析。同时考察不同羟基硅油的添加量对胶粘剂固化时间、固化膜吸水性、粘结性能等的影响。结果适量添加羟基硅油可以有效提高胶粘剂的粘接强度、耐热性和耐水性,但是羟基硅油添加量过多会延长预聚体的合成时间。结论羟基硅油添加的质量分数为3%～4%时最佳。     

用聚合-溶解-析出法制备强疏水性聚酯

以聚对苯二甲酸乙二酯(PET)为分子链主要成分,引入第三单体聚羟基氟硅油(FGX),共聚出疏水改性共聚酯(MPET).用1H-NMR、ESCA对MPET进行表征,研究了溶解-析出条件对MPET材料表面形貌、疏水性能及力学性能的影响.结果表明,样品表面结晶析出粒子的形状和疏水效果与溶解时间相关.用溶解-析出法制备的强疏水...     

羟基硅油改性聚丙烯酸酯粘合剂的制备与表征

采用种子乳液聚合法制备了一种新型羟基硅油改性丙烯酸酯粘合剂,并讨论了有机硅用量对乳胶膜的耐水性和耐溶剂性的影响;比较了羟基硅油改性前后粘合剂的力学性能,通过红外光谱和透射电镜分析了改性后的粘合剂的结构和形貌.结果表明,羟基硅油改性后粘合剂的耐水性、耐溶剂性和力学性能得到改善.红外光谱分析表明,羟基硅油与丙烯酸酯以Si-O-C键结合;透射电镜分析表明,其有明显核壳结构.     

四苯基苯基甲基乙烯基硅橡胶的合成及性能研究

以羟基封端多乙烯基硅油,四苯基环戊二烯酮,α-氯萘为原料,通过Diels-Alder反应制得了一种具有稠环结构的四苯基苯基多乙烯基硅油。并对四苯基苯基多乙烯基硅油进行了表征;并分别以四苯基苯基多乙烯基硅油、含氢硅油,乙烯基硅油为原料,通过硅氢加成反应室温硫化制备了四苯基苯基甲基乙烯基硅橡胶,并对四苯基苯基甲基乙烯基硅橡胶的热性能、拉伸强度、剪切强度的性能进行了测试。结果表明:在四苯基苯基多乙烯基硅油添加量为4%(wt,质量分数)条件下,四苯基苯基甲基乙烯基硅橡胶初始分解温度为449.06℃,拉伸强度为1.42MPa,剪切强度为0.84MPa,热稳定性能和力学性能得到提高。     

氟硅油的合成及应用

氟硅油具有优良的耐油、耐溶剂及耐候性。介绍了氟硅油制备过程中的单体合成、分离及水解、开环共聚,论述了氟硅油及其二次产品的应用,展望了其发展前景。     

液晶聚合物/聚苯胺复合材料的导电性能研究

以4,4'-二羟基-a,a'-二甲基苄连(DDBA)羟基硅油合成了系列带有磺酸基团的液晶离聚物(LCI).合成的LCI与聚苯胺原位聚合制备出系列复合材料.采用红外光谱表征了LCI和复合材料的结构;用差示扫描量热法表征了复合材料的液晶性能;交流阻抗法测量了复合材料的电导率;结果表明:掺杂后的最大电导率能达到9.0×10-5/cm.     

羟基硅油改性CaO-SiO2-TiO2有机-无机杂化材料的制备与显微结构

采用溶胶-凝胶法制得了均匀、无裂纹的羟基硅油改性CaO-SiO2-TiO2有机-无机杂化材料。X射线衍射谱图和傅立叶红外吸收光谱的研究表明,制得的材料是非晶态的,由结合了聚二甲基硅氧烷链段的二氧化硅和二氧化钛网络组成,其中钙离子以离子键形式与网络相结合。通过对凝胶粉末的差热分析和热失重分析,确定了材料的热处理制度。通过扫描电子显微镜对材料表面的显微结构进行了观测和表征。溶胶-凝胶法制得的有机-无机杂化材料通常显示低弹性模量、高延展性及高机械强度。因此,羟基硅油改性CaO-SiO2-TiO2杂化材料有望成为一种新型的骨修复材料。     

光固化有机硅改性聚氨酯丙烯酸酯的研制及涂膜性能研究

主要介绍了研制光固化有机硅改性聚氨酯丙烯酸酯用原料硅羟基硅油与烷羟基硅油的选择、合成路线的优化,以及树脂中硅含量的不同对形成涂膜后耐候性的影响。     

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.     

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.     

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.……     

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.