聚六亚甲基碳酸酯二醇增韧环氧树脂的结构与性能

采用羟基封端的脂肪族碳酸酯－聚六亚甲基碳酸酯二醇对环氧树脂进行了增韧，通过扫描隧道显微镜，扫描电子显微镜，差示扫描量热分析以及动态力学性能分析等方法研究了增韧ＥＰ的结构与性能的关系。     

大豆油基多元醇改性水性聚氨酯胶黏剂的制备及性能研究

分别以自制大豆油基多元醇(P-OA-ESBO)、聚己二酸-1,4-丁二醇酯二醇(PBA)、聚ε-己内酯二醇(PCL)为原料制备了不同结构的脂肪族水性聚氨酯胶黏剂,在相同的R(NCO/OH)比和亲水基含量下对不同聚氨酯乳液进行了红外光谱、粒径、透射电镜、热重和差示热量表征及性能测试。结果表明:与以传统的石油类多元醇制备的水性聚氨酯相比,大豆油基多元醇改性的聚氨酯乳液粒径稍有增大,粘接强度有所下降,同时也展现出了良好的拉伸性能和较好的耐水性,且原料绿色可再生。     

基于不同碳链长度二元酸的脂肪族聚酯的合成及性能

分别以5种不同碳链长度的脂肪族二元酸(C4、C6、C8、C10、C12)和丁二醇为单体,采用先酯化后缩聚的两步法合成一系列脂肪族聚酯:聚丁二酸丁二醇酯(PBS)、聚己二酸丁二醇酯(PBA)、聚辛二酸丁二醇酯(PBSu)、聚癸二酸丁二醇酯(PBSe)和聚十二烷二酸丁二醇酯(PBD)。研究了脂肪族二元酸单体的碳链长度对5种聚酯的结构、热性能和力学性能的影响。研究表明,5种聚酯的Mw在125000~250200之间,其结果与特性黏度具有一致性。随着脂肪族二元酸碳链长度的增加,聚酯的T_c,T_m和T_g均先降低后升高;PBSu(C8)的结晶度最高(71.2%),PBA(C6)的结晶度最低(33.8%)。随着碳链长度的增加,聚酯的初始分解温度逐渐向高温区移动,聚酯的拉伸强度逐渐降低;断裂伸长率先增加后降低,PBS(C4)的拉伸强度最大(58.55 MPa),PBSu(C8)的断裂伸长率最大(897.2%)。5种脂肪族聚酯均属于典型的假塑性流体。     

聚醚酯型聚氨酯弹性体的结构与阻尼性能关系

以丙氧基新戊二醇(PONPG)与二元酸缩聚反应合成了聚丁二酸丙氧基新戊二醇酯(PNPS)和聚己二酸丙氧基新戊二醇酯(PNPA),再与2,4-甲苯二异氰酸酯(TDI-100)和3,3’-二氯-4,4’-二氨基二苯甲烷(MOCA)制备聚醚酯型聚氨酯(PU)弹性体。用傅里叶变换红外光谱、凝胶渗透色谱和核磁共振对聚醚酯二醇结构及相对分子质量进行了测试,用原子力显微镜表征了PU弹性体的微观结构、DMA表征了聚醚酯二醇种类及相对分子质量对PU弹性体阻尼性能的影响。结果表明,随着聚醚酯二醇相对分子质量增加,PU弹性体的损耗因子最大值(tanδmax)增加,阻尼温域明显地向低温方向移动。PU的AFM谱图的相畴随聚醚酯二醇相对分子质量的增加而增大,三维立体图呈现出高低不平的丛林状形貌。对相同相对分子质量聚醚酯二醇,由PNPA反应制备的PU弹性体,其tanδmax较低,且更偏向于低温区域。     

脂肪族聚酯的热稳定性研究

用热失重(TG)和F lynn方法(等转化率方法)研究了聚丁二酸乙二醇酯(PESu),聚丁二酸丁二醇酯(PBSu),聚丁二酸已二醇酯(PHSu),聚癸二酸己二醇酯(PHSe)的热稳定性。结果表明,这些聚酯的热分解温度和分解活化能均随酯基浓度的降低而升高。该研究可对脂肪族聚酯的分子设计、合成和加工工艺提供参考。     

长支链聚碳酸丁二酯的制备及表征

脂肪族聚碳酸丁二酯是一种有着广泛应用前景的生物可降解材料,但是材料在加工过程中发生的热降解反应及材料本身存在的熔体强度低、拉伸强度低等缺陷却大大限制了其应用。为此,采用反应加工的方式对聚碳酸丁二酯进行改性,通过在共混体系内加入多官能团单体的方法来制备长支化的聚碳酸丁二酯。探索出了一种用酸酐类和环氧类多官能单体联用的方法,制备得到了高支化度、高分子量的聚碳酸丁二酯,并通过凝胶渗透色谱仪(GPC)及流变学方法,表征了长支化结构的产生,并推测了制备长支化聚碳酸丁二酯的官能团反应过程及可能出现的支化结构。研究结果表明,与未改性的聚碳酸丁二酯相比,改性后的样品力学性能得到明显改善,采用多官能单体联用的方法制备得到的长支化样品的力学性能最优。     

不同低聚多元醇软段结构水性聚氨酯膜的制备

分别以相对分子质量均为2000的聚丙二醇(PPG)、聚四氢呋喃醚二醇(PTMG)、聚己二酸己二醇酯二醇(PHA)和聚己二酸乙二醇酯二醇(PEA)为软段原料,以异佛尔酮二异氰酸酯(IPDI)和小分子多元醇、小分子多元胺为硬段原料制备了系列水性聚氨脂(WPU)膜。通过红外光谱、动态力学热分析,以及溶胀和溶解选择因子、渗透汽化分离苯/环己烷测试对膜的结构和性能进行了表征。研究表明,WPU-PTMG膜硬段结合紧密,WPU-PPG膜溶胀率和渗透汽化通量较大;WPU-PEA膜的酯基密度较大,微相分离程度较高,对苯的亲和性最好;WPU-PHA膜的酯基密度小于WPU-PEA膜,其溶胀率和渗透汽化通量大于WPU-PEA。     

不同低聚多元醇软段结构水性聚氨酯膜的制备EI北大核心CSCD

分别以相对分子质量均为2000的聚丙二醇(PPG)、聚四氢呋喃醚二醇(PTMG)、聚己二酸己二醇酯二醇(PHA)和聚己二酸乙二醇酯二醇(PEA)为软段原料,以异佛尔酮二异氰酸酯(IPDI)和小分子多元醇、小分子多元胺为硬段原料制备了系列水性聚氨脂(WPU)膜。通过红外光谱、动态力学热分析,以及溶胀和溶解选择因子、渗透汽化分离苯/环己烷测试对膜的结构和性能进行了表征。研究表明,WPU-PTMG膜硬段结合紧密,WPU-PPG膜溶胀率和渗透汽化通量较大;WPU-PEA膜的酯基密度较大,微相分离程度较高,对苯的亲和性最好;WPU-PHA膜的酯基密度小于WPU-PEA膜,其溶胀率和渗透汽化通量大于WPU-PEA。     

脂肪族聚碳酸亚丙酯的脱溶方法

采用甲醇洗涤聚合产物脂肪族聚碳酸亚丙酯中残余的环氧丙烷、催化剂,使脂肪族聚碳酸亚丙酯中的灰份降低,过量的环氧丙烷脱出。     

聚(衣康酸丁二醇酯癸二酸丁二醇酯)的合成与表征

以衣康酸(IA)、癸二酸(SA)和1,4-丁二醇(BDO)为反应单体,采用熔融酯化缩聚法合成了一系列新型可生物降解脂肪族聚(衣康酸丁二醇酯癸二酸丁二醇酯)(PBIS)。采用核磁共振、凝胶渗透色谱、差示扫描量热、热失重分析和酶降解测试等方法对共聚酯的结构和性能进行了表征。凝胶渗透色谱测试结果表明,随着共聚酯中衣康酸含量的增加,其数均相对分子质量先减小后增大;差示扫描量热分析得出,产物的熔点和结晶温度随衣康酸含量的增加而下降;热失重分析表明,共聚酯拥有较好的热稳定性;酶降解测试得出共聚酯具有良好的生物降解性,且降解速率随衣康酸含量的增加而加快。     

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.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

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.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

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.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.