一种新型UV固化超支化水性聚氨酯的合成及性能研究

以异佛尔酮二异氢酸酯(IPDI)、聚碳酸酯二元醇(PCDL)、端羟基聚醚改性硅油(THPDMS)、二羟甲基丙酸(DMPA)和甲基丙烯酸羟乙酯(HEMA)为主要原料,合成了单NCO封端的聚氨酯预聚物,然后将其接枝到二季戊四醇(Di-PE)核分子上,合成一种新型UV固化超支化水性聚氨酯树脂。通过调节有机硅含量制备出一系列不同有机硅含量乳液及胶膜,对其结构、性能进行表征。实验结果表明,随着有机硅含量增加乳液粒径逐渐增大、分布变宽,胶膜耐水性和热稳定性增强。拉伸强度先增大后降低。     

织物涂层用含氟硅油改性聚氨酯水分散体的合成与表征

为合成高性能织物涂层剂,以聚四氢呋喃醚、聚乙二醇、端氨基含氟硅油为混合软段,合成了有机硅改性的水性聚氨酯(WFSPU)。用红外光谱、核磁共振谱表征了改性聚氨酯的化学组成;通过纳米粒度测定及Zeta电位分析考察了乳液的稳定性;通过差热扫描量热、正电子湮灭谱及静态拉伸试验分别研究了WFSPU膜的热性能、自由体积空洞及力学性能。研究结果表明,当含氟硅油用量(质量分数)<10%时,可以制得稳定的乳液,聚氨酯膜的软段玻璃化转变温度约为-78℃。当含氟硅油质量分数为6%时,WFSPU膜的拉伸模量最高,达到47.33 MPa,断裂伸长率为663.49%。     

有机硅改性水性聚氨酯的研究进展

综述了有机硅改性水性聚氨酯的研究发展,主要包括有机硅、有机硅-环氧树脂、有机硅-丙烯酸酯和无机纳米SiO2对水性聚氨酯改性的不同方法和特点,相应地介绍了这些改性水性聚氨酯在不同领域的应用进展,并对有机硅改性水性聚氨酯的未来发展前景作了展望。     

改性有机硅及其竹基材料的制备条件

通过试验筛选出合成有机硅树脂的较佳条件,并且通过聚氨酯与有机硅树脂的共混得到改性有机硅树脂,将所得改性有机硅树脂应用于竹基材料的表面涂装,以获取最佳的改性有机硅竹基材料的制备条件.结果表明：有机硅树脂的合成最佳条件为以苯基三甲氧基硅烷与甲基二甲氧基硅烷为合成单体,且两单体的体积之比为1.5,水解温度为55 ℃,水解时间为2.5 h,w（HCl）：w（Si——OR）,w（H2O）：w（Si——OR）,w（H2O）：w（二甲苯）：w（丙酮）分别为0.002 00,10：3和8：4：1;改性硅树脂竹基材料的最佳制备条件为聚氨酯与硅氧烷的添加质量分数为树脂总质量的12.5%,固化剂用量为树脂总质量的24.5%,并于80 ℃条件下烘烤3 h;红外光谱分析表明,有机硅树脂在—Si—O—Si—有较宽的吸收峰;耐化学腐蚀性试验结果表明,所合成的有机硅改性树脂漆膜具有很好的耐化学腐蚀性能.     

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。     

水性光固化聚脲的制备与性能研究

优化马来酸二乙酯改性己二胺反应条件，并与异氰酸酯丙烯酸乙酯(AOI)反应，制备了含端双键的一元胺，采用异佛尔酮二异氰酸酯(IPDI)、聚醚胺(PEA,数均分子量M_n约2000)、改性己二胺、二乙基甲苯二胺(DETDA)、乙二胺基乙磺酸钠盐(AAS盐)为主要原料，制备了一系列水性光固化聚脲。采用红外光谱(FT-IR)、核磁氢谱(¹H-NMR)对合成树脂的结构进行了表征探究，采用纳米粒径分析仪、紫外分光光度计、光学接触角测量仪、热重分析仪等手段对乳液和涂膜进行一系列测试表征。结果表明：制备了水性光固化聚脲树脂，其中脂肪族聚脲树脂体系的乳液以及热稳定性更好，芳香族聚脲树脂体系的基本性能更好。     

水性丙烯酸酯涂料改性的研究进展

介绍了环氧树脂改性水性丙烯酸涂料、有机氟改性水性丙烯酸涂料、聚氨酯改性水性丙烯酸涂料、有机硅改性水性丙烯酸涂料及外加纳米助剂改性水性丙烯酸涂料的研究进展,经过改性水性丙烯酸树脂涂料能够获得优良的综合性能,提高了水性丙烯酸树脂涂料的使用性能,扩大了水性丙烯酸树脂涂料的推广应用范围。提出了当前水性丙烯酸改性研究存在的难题,指出将来水性丙烯酸涂料的研究应朝着多功能、高性能、多样化和绿色化方向发展。     

耐热线型小分子对有机硅耐温吸波涂层的增韧改性研究

目的 采用能与有机硅单体反应的耐热小分子对苯基硅树脂基吸波涂层进行增韧改性,调控有机硅树脂的交联网络结构,并将改性树脂与耐温吸波剂复合,制备具有高柔韧、高附着力和耐温的吸波涂层。方法 将不同端基或链长的耐热增韧剂通过硅氢加成接枝到有机硅树脂基体,改变基体的交联网络结构,通过红外、扫描电镜、万能电子试验机、动态热机械分析仪和矢量网络分析仪测试其性能。结果 随着乙烯基封端聚二甲基硅氧烷含量的增加,涂层的柔韧性提高,但耐温性能和附着力降低;当乙烯基封端聚二甲基硅氧烷质量分数为45%时,1 mm涂层的柔韧性达20 mm,附着力达7.73 MPa,抗冲击性大于50 kg·cm。在300℃热处理15 h后,改性涂层挠度从未改性时的1.08 mm提升至1.35 mm,涂层在高温工作后仍保持较好的柔韧性。结论 采用耐热线型小分子对有机硅树脂交联网络结构进行改性,可有效地调控耐温吸波涂层的力学性能,为耐高温吸波涂层增韧及其工程应用提供参考。     

硅烷改性水性聚氨酯表面施胶剂的制备与性能研究

以甲苯二异氰酸酯、混合多元醇为基本原料,N-甲基二乙醇胺为亲水扩链剂,有机硅为改性剂,通过醋酸中和反应制备出一种可用于纸张表面施胶的自乳化阳离子水性聚氨酯乳液;研究了硅烷用量、预聚温度、R值(体系中异氰酸酯基和羧基的摩尔比)、聚酯＼聚醚质量比对乳液性能和施胶效果的影响.结果表明:硅烷用量为4.5％,预聚温度为60℃,R值为1.10,聚酯＼聚醚质量比为3.6时制备的乳液性能良好;FT-IR分析表明有机硅烷已通过化学方法结合到聚氨酯分子链中;TGA分析表明有机硅的加入对水性聚氨酯耐热性有明显提高;粒径分析表明,有机硅的加入能使乳液粒子分布更均匀且粒径更小;施胶效果表明水性聚氨酯对改善纸张强度作用明显,有机硅烷的加入能显著提高纸张的施胶度.     

光固化水性聚氨酯导热涂层的制备及性能

为了提高光固化水性聚氨酯(WPU)涂层的导热性能,采用硅烷偶联剂和半封端聚氨酯来改性纳米氧化铝(Al_2O_3),将改性后的纳米Al_2O_3加入水性聚氨酯中制备了Al_2O_3/光固化水性聚氨酯导热复合涂层。利用光学接触角仪、电子拉力机、热重分析仪等对涂层的性能进行了研究,探讨不同Al_2O_3的改性方法对涂层耐水性、力学性能、水接触角、热稳定性和导热性能的影响,并用扫描电子显微镜(SEM)对材料断面的形貌进行了观察。结果表明:不同的Al_2O_3改性方法对光固化涂层的导热性能有较大的提高,热性能和接触角提高,拉伸强度和断裂伸长率也有一定增加。     

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.……     

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...     

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.     

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.     

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...