水性低羟基值丙烯酸改性醇酸树脂的制备及应用研究

为了改善水性醇酸涂料的干燥性能和防腐性能,以妥尔油酸、苯甲酸、顺丁烯二酸酐、三羟甲基丙烷、间苯二甲酸反应制备醇酸树脂,采用含羟基的丙烯酸类单体对醇酸树脂进行改性,制备了性能优异的水性低羟基值丙烯酸改性醇酸树脂。以改性后的水性低羟基值丙烯酸改性醇酸树脂为成膜物质,设计了水性羟基丙烯酸改性醇酸涂料,讨论了脂肪酸种类、醇酸树脂的油度、丙烯酸单体用量、醇酸树脂羟基值、改性树脂羟基值、醇酸树脂和丙烯酸酯类单体比例及助溶剂等因素对树脂性能的影响。结果表明：制备的水性羟基丙烯酸改性醇酸涂料在低温、高湿环境中干燥速度快、机械性能好,同时具有优异的耐候性和防腐性能。     

环氧改性自干型水性醇酸树脂的影响因素分析

采用亚麻油、甘油、邻苯二甲酸酐以及顺丁烯二酸酐作为原料合成醇酸树脂,并在酯化反应中后期加入环氧树脂,利用醇酸树脂分子端羧基与环氧基的反应对醇酸树脂进行改性。环氧树脂的分子量越大,在溶剂中溶解度越小,与醇酸树脂的混溶性越差;醇酸树脂的酸值越低,与环氧树脂的混溶性越差,经环氧树脂改性后的醇酸树脂,分子量分布相对较窄,而且大分子量组分的比例明显增加,证明环氧树脂确实起到了增加醇酸树脂分子量、改善其涂膜性能的作用。选用中等分子量的环氧树脂E-20,用量为理论计算值的90%左右,质量分数为19%,最佳投料时间为35~40mg KOH/g,此时环氧树脂与醇酸树脂的混溶性好,反应程度高,产物基本透明,粘度适宜。     

水性环氧丙烯酸酯的制备与表征

通过双羟基化合物中的羟基与环氧树脂反应 ,获得具有亲水链段两端为环氧基的改性环氧树脂 ,然后和丙烯酸羧基发生酯化反应 ,制得水性环氧丙烯酸酯。研究了催化剂种类、催化剂用量和反应温度对转化率的影响 ,结果表明选用KOH作催化剂 ,用量为 0 7% ,反应温度为 90℃时所得产物外观和水溶性都很好。采用FT IR红外光谱对所合成的树脂的结构进行了表征 ,表明获得了目的结构的产物。     

有机氟阴极电泳涂料的制备工艺

水性含氟涂料既具有氟树脂的耐候、耐污、耐腐蚀等性能,又具有水性涂料环保、安全等性能,目前国内对此研究还不够深入。以环氧树脂为主体,选择合适的丙烯酸单体、有机氟单体对其改性,合成了同时具备环氧树脂、丙烯酸树脂、氟树脂性质的阳离子型含氟环氧丙烯酸树脂,并以此为主体树脂制备出水稀释型阴极电泳涂料,重点探讨了含氟单体的种类和数量、反应温度、反应时间等因素对树脂合成以及漆膜性能的影响。结果表明:在合适的工艺条件下,可以得到高耐腐蚀性、耐老化性、自洁性的电泳漆膜。     

W30—11有机硅漆冷混改性中油度醇酸漆试验

采用物理冷混法,将适量W_(30.11)有机硅烘干绝缘清漆掺入中油度C_(01-1)醇酸清漆或自制醇酸树脂的二甲苯溶液中,得到改性醇酸清漆;采用相同基料和类似方法,研制成了相应的磁漆和铝粉漆。测试证明:所研制的清漆、磁漆和铝粉漆能室温固化,所成漆膜表面光亮,机械性能、耐常见介质腐蚀性能以及其它综合性能良好,还具有优良的耐热性能。     

丙烯酸改性醇酸树脂热变色涂料的研究

论述了丙烯酸改性醇酸树脂和热变色材料的制备方法,并将热变色材料分散于丙烯酸改性醇酸树脂中,制备出丙烯酸改性醇酸树脂热变色涂料.结果表明:所得的丙烯酸改性醇酸树脂热变色涂料的性能优良,受热变色效果明显.     

系列紫外光-热混杂固化树脂的合成及其性能

合成了一系列同时具有光固化基团(双键)和热固化基团(环氧)的聚氨酯改性丙烯酸环氧单酯。用红外光谱(FT-IR)表征了固化过程特征吸收峰的变化,测试了柔性链段对聚氨酯改性丙烯酸环氧单酯光-热混杂固化膜的凝胶率、吸水率、力学性能、体积收缩率和热性能的影响。结果表明,在相同稀释剂条件下,与丙烯酸环氧单酯光-热固化膜相比,聚氨酯改性丙烯酸环氧单酯光-热固化膜的凝胶率可达97%以上,断裂强度有所下降,但断裂伸长率由4.6%提高到19.5%,体积收缩率由6.07%下降到4.22%,光-热固化膜的热分解温度超过了240℃。     

苯乙烯改性醇酸树脂及快干醇酸漆的研制

以脂肪酸、季成四醇、苯酐和顺酐为原料合成基础醇酸树脂,通过比较几种不同的苯乙烯改性醇酸树脂方法,确定采用后苯乙烯化法的改性工艺路线,并对到树脂的合成及改性工艺条件进行了优化。检测结果表明,所得改性树脂具有颜色浅、快干、硬度高、综合性能较好等特点。     

AECATI改性部分丙烯酸环氧酯树脂

采用自制4-丙烯酰氧乙氧甲酰氨基甲苯2-异氰酸酯(简称AECATI)与自制部分丙烯酸环氧酯树脂(制备时环氧树脂E-51中的环氧基与所用丙烯酸羧基的当量比为1:0.6)的羟基反应,制得本改性树脂;经优选试验,得到了适宜于本改性树脂的成膜条件及其清漆适用的固化条件,所成漆膜综合性能良好,耐水性能优良。     

短油度水性醇酸树脂的合成工艺研究

采用熔融聚合成盐法合成短油度水性醇酸树脂,考察了醇超量r、聚合阶段酸值和终点酸值、分子量及分布、偏苯三酸酐的加入量等对树脂水分散性及漆膜性能的影响。试验结果表明,醇超量r在25%、聚合阶段酸值控制在20 mgKOH/g、终点酸值在55~65 mgKOH/g、偏苯三酸酐加入量为二元酸摩尔量的1/4~1/5范围时树脂综合性能较好。分子量及分布对树脂水分散性及漆膜性能影响较大,控制数均分子量在2500左右,分子量分布系数在12左右为宜。     

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.……     

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.     

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...     

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 ...