丙烯酸-丙烯酰胺合成树脂的制备及其性能研究

采用水溶液聚合的方法,以丙烯酰胺(AM)和丙烯酸(AA)为单体,以过硫酸钾(KPS)和亚硫酸氢钠为引发剂,N,N′-二甲基双丙烯酰胺(NMBA)为交联剂,来制备丙烯酸-丙烯酰胺合成吸水树脂。研究了其工艺过程并对其性能进行了测试。结果表明:在30℃下,丙烯酸-丙烯酰胺共聚树脂的最佳制备条件为:单体浓度为25%,n(AA)∶n(AM)=4∶1,中和度为75%,交联剂的用量和引发剂的用量分别为单体质量的0.04%和0.3%,所得到的树脂最佳吸纯水倍率及最佳吸0.9%(质量分数)NaCl溶液倍率分别为980g/g和95g/g。     

聚合物P(AMPS-AM-DMAM-NVP)的制备及降滤失性能

以2-丙烯酰胺基-2-甲基丙磺酸(AMPS)、丙烯酰胺(AM)、N,N-二甲基丙烯酰胺(DMAM)、N-乙烯吡咯烷酮(NVP)为单体,采用自由基水溶液聚合法制备P(AMPS-AM-DMAM-NVP)。通过正交实验设计得到最佳反应条件:引发剂用量0.3%,单体的物质的量比AMPS∶AM∶DMAM∶NVP=3∶4∶2∶1,乙二胺四乙酸(EDTA)用量0.15%,温度75℃,单体质量分数30%;采用红外光谱和TG-DSC分析法对其进行表征;并考察其降滤失性能。结果表明,聚合物质量分数增加,滤失量降低;在饱和盐水泥浆中,聚合物的加入使滤失量从105.6 mL降到7.5 mL,降滤失效果明显。     

羧甲基含共价氮高吸水树脂的合成及其性能研究

羧甲基马铃薯淀粉(AA)接枝丙烯酸(AC)、丙烯酰胺(AM)正交优化合成含共价氮高吸水树脂,最大吸蒸馏水率1700g/g。最优制备方案为:AA∶AC(质量配合比)=1∶7,AA∶AM(质量配合比)=1∶10;交联剂为0.08%(相对AA的质量分数);引发剂为0.45%(相对AA的质量分数);单体中和度为50%;体系总水量85mL。红外光谱、元素分析和热重分析表明,该高吸水树脂耐热性能优良,在395℃之前较稳定;高温下保水率较高,80、120℃时,4h的保水率分别大于70%和30%。     

水溶性AA/AM/AHPSE/DNDA四元共聚物驱油剂的合成及性能研究

以丙烯酸(AA)、丙烯酰胺(AM)、3-烯丙氧基-2-羟基-丙烷磺酸钠(AHSPE)和N,N-二烯丙基油酸酰胺(DNDA)为原料,制备了一种水溶性四元共聚物AA/AM/AHPSE/DNDA。确定了最佳合成条件:温度35℃、pH=7、m(AA)∶m(AM)∶m(AHPSE)∶m(DNDA)=69.7∶25∶5∶0.3%和引发剂加量0.3%(wt,质量分数,下同)。对共聚物进行了FT-IR和1 H-NMR表征。2g/L该共聚物溶液在Na+、Ca2+、Mg2+浓度为20、2和2g/L时,表观黏度分别为35.1、33.8和34.5mPa·s,黏度保留率分别为17.3%、16.7%、16.4%;在剪切速率为170s-1时共聚物黏度保留率为13.2%;在65℃下该共聚物盐溶液可提高原油采收率13.0%。     

无N2下合成钠基膨润土/P(AA-AM)复合吸水树脂的研制

以N,N'-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,丙烯酸(AA)和丙烯酰胺(AM)为单体,采用水溶液聚合法合成出钠基膨润土复合聚丙烯酸钠-丙烯酰胺复合吸水树脂.研究了钠基膨润土的添加量、交联剂用量、引发剂用量、中和度及AM的用量对吸水倍率的影响.结果表明,钠基膨润土用量为40%,交联剂用量为0.025%,引发剂用量为0.3%,AM用量为12%及AA的中和度为80%时,吸蒸馏水倍率与吸收0.7%NaCl溶液倍率分别为422.28 g/g和65.80 g/g.     

壳聚糖接枝共聚制备高吸水性树脂的研究

以壳聚糖(CTS),丙烯酸(AA),丙烯酰胺(AM)为原料,N,N-亚甲基双烯酰胺(MBAM)为交联剂,NaH-SO3/K2S2O8氧化还原体系为引发剂,通过接枝共聚合反应制备高吸水性树脂。较佳制备条件为:m(CTS)∶m(AA)∶m(AM)为1∶3∶1,丙烯酸的中和度为70%,引发剂用量4%,交联剂用量0.04%,反应温度45℃。研究表明,此条件下所得树脂吸水率为402g/g,吸盐水(浓度0.9%)率为102g/g,并最后采用红外光谱、扫描电镜表征分析了树脂的结构。     

高分子量两性聚丙烯酰胺长时间稳定的水分散体制备

以丙烯酰胺(AM)、顺丁烯二酸(MA)及二甲基二烯丙基氯化铵(DMDAAC)为聚合单体,由偶氮二异丁咪唑啉盐酸盐(VA-044)为引发剂,采用水分散聚合法合成了高分子量两性聚丙烯酰胺(AmPAM)水分散体系。研究了分散体颗粒形貌以及单体浓度、单体摩尔比、引发剂用量、聚合温度、pH值等条件对聚合反应的影响。研究表明,AmPAM分子由稳定剂包裹以球形状态存在,均匀分散在硫酸铵溶液中,且当分散稳定剂用量为0.45 g/g,单体质量分数为20%,硫酸铵质量分数为25%,单体摩尔比为1∶8∶1,引发剂质量分数为0.05%,温度55℃,pH值为7时,相对分子质量高达4.12×107,体系稳定时间达到240 d以上。     

AA/AM二元共聚超强吸水剂的合成

以丙烯酰胺(AM)和丙烯酸(AA)为原料,用蒙脱土(MMT)作为无机添加剂,依据均匀设计法设计试验,采用水溶液聚合法合成了抗温抗盐性吸水剂.应用模糊优化设计理论,在建立吸水剂性能指标多目标隶属函数的基础上,对吸水剂的膨胀度、抗温性和抗盐性进行了综合研究,得到了优化合成工艺:单体AM和从的质量配比为5:1,交联剂质量分数为0.09%,引发剂质量分数为0.05%,MMT质量分数为7.5%;该吸水剂的综合性能:膨胀度为149g/g,在80℃下的抗温系数为0.73,在10%NaCl溶液中的抗盐系数为0.48.     

叔丁醇-水基凝胶注模工艺因素研究

以叔丁醇-水混合介质为溶剂,丙烯酰胺(acrylamide, AM)为单体进行凝胶注模成型,研究了叔丁醇含量、反应温度、引发剂和催化剂加入量等参数对凝胶时间与胶体形态的影响。结果发现,凝胶时间随叔丁醇用量的增加而增加,但随反应温度的提高显著下降;随引发剂含量的增加,凝胶时间先快速降低至一定水平后保持较为稳定的状态,继续增加引发剂用量,凝胶时间基本呈线性增加;随催化剂用量的增加,凝胶时间持续减少,在催化剂加入量较低时凝胶时间变化显著。在反应温度25℃、叔丁醇含量30%(体积分数)、引发剂2.5%(质量分数)、催化剂0.1%(质量分数)时,凝胶时间为25 min,凝胶时间适宜,所得样品表面质量良好,干燥收缩率较低,能够满足实际需要。     

微波辐射海带接枝AA/AM合成高吸水树脂

以N,N-亚甲基双丙烯酰胺为交联剂,通过微波辐射法制备了海带接枝丙烯酸(AA)和丙稀酰胺(AM)高吸水树脂。讨论了单体配比、丙烯酸中和度、交联剂用量及引发剂用量、辐射时间等因素对吸水性能的影响,采用响应面分析法优化合成条件,并用红外光谱对产物进行了表征。研究结果表明:当海带用量35%,AM∶AA比例为20%,引发剂用量8.1%,交联剂用量0.052%,NaOH的中和度为79.3%,辐射时间45s时,制备的高吸水树脂的吸自来水倍率达176.62g/g。     

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.……     

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.     

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.     

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 ...