聚(丙烯酸-丙烯酰胺)/绢云母复合高吸水树脂的制备及其机理探讨

以过硫酸钾(KPS)为引发剂,N,N’-亚甲基双丙烯酰胺(NMBA)为交联剂,丙烯酸(AA)、丙烯酰胺(AM)和绢云母为原料,采用快速水溶液聚合法,在没有氮气保护的条件下制备有机-无机复合高吸水树脂。采用傅里叶红外光谱(FT-IR)、扫描电镜(SEM)对复合高吸水树脂结构进行了表征。考察了单体配比、绢云母用量、丙烯酸中和度、交联剂用量、引发剂用量对高吸水树脂吸液性能的影响。得到了最佳聚合反应条件:丙烯酰胺与丙烯酸的质量比为1∶5,交联剂用量为0.014%,引发剂用量为0.2%,绢云母用量为5%,丙烯酸中和度为80%,反应温度为65℃。在此条件下制备的复合高吸水树脂的蒸馏水吸收倍率为790g/g,0.9%的NaCl水溶液的吸收倍率为69.8g/g。最后,对聚(丙烯酸-丙烯酰胺)/绢云母复合高吸水树脂的机理进行了探讨。     

PVA类高吸水性树脂的制备

以PVA为原料,用顺丁烯二酸酐作交联剂制得了PVA类高吸水性树脂.研究了交联剂用量、反应温度、PVA聚合度以及处理产物的溶液pH值对树脂吸水率的影响.得到的最佳制备条件为:ω(顺丁烯二酸酐/PVA)为30%,反应温度在98～105℃,所用PVA的聚合度为1700,处理产物的溶液pH值为10左右.     

三元共聚高吸水树脂的简易合成

在没有氮气保护和引发剂作用下,以N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,采用静置热聚合法成功合成了2-丙烯酰胺基-2-甲基丙磺酸(AMPS)/丙烯酰胺(AM)/壳聚糖(CTS)三元共聚高吸水树脂。同时研究了反应条件对树脂吸水倍率的影响,并借助FT-IR对树脂的分子结构进行了分析。实验结果表明,所合成的树脂最佳反应条件为:n(AM)∶n(AMPS)=3∶1,ω(CTS)=2%,ω(NMBA)=0.05%,pH=1.5,固含量为15%。在此条件下合成的高吸水树脂室温下最大吸蒸馏水倍率为1302g/g。     

四烯丙基氯化铵交联的耐高温吸水树脂的研究

采用水溶液聚合法,以丙烯酸(AA)、2-丙烯酰胺基-2-甲基丙磺酸(AMPS)为单体,四烯丙基氯化铵(TAAC)为交联剂,过硫酸铵(APS)为引发剂,制备了耐高温吸水树脂,考察了单体配比、引发剂和交联剂用量对吸水树脂在高温下吸水性能的影响,并对吸水树脂结构进行扫描电镜分析。研究结果表明,所合成的吸水树脂具有良好的耐高温性能,最佳合成条件:AMPS与AA的质量比为0.22,引发剂、交联剂与单体的物质的量比分别为0.11%、0.14%,此条件下合成的吸水树脂在300℃蒸馏水中的吸水倍率为248g/g。     

静置热聚合法合成AMPS/AM/CMC三元共聚高吸水树脂

在没有氮气保护的作用下,以N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,以过硫酸铵(APS)为引发剂,采用静置热聚合法合成2-丙烯酰胺基-2-甲基丙磺酸(AMPS)/丙烯酰胺(AM)/羧甲基纤维素钠(CMC)三元共聚高吸水树脂。研究了反应条件对树脂吸水率的影响,并借助FT-IR、TG-DTA和偏光对树脂的分子结构、热稳定性和表面形态进行了分析。实验结果表明:所得树脂的最佳反应条件为:n(AM)∶n(AMPS)=1∶1、ω(APS)=0.45%、ω(CMC)=9%、ω(NMBA)=0.085%和pH=1.2,在此条件下合成的高吸水树脂室温下最大吸蒸馏水倍率为909g/g。     

羟化聚天冬氨酸高吸水性树脂的制备及性能研究

以中间体聚琥珀酰亚胺( PSI)为原料,己二胺为交联剂,无水乙醇为分散剂,采用乙醇胺对其进行改性,制备了羟化聚天冬氨酸高吸水性树脂(HPASP).研究了PSI相对分子质量、反应温度、交联剂用量、乙醇胺用量及无水乙醇用量等因素对树脂吸水性能的影响.结果表明,树脂在蒸馏水和0.9％ NaCl水溶液中的吸水率分别达到804g...     

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。     

高吸油性树脂的合成及性能研究

采用悬浮聚合法合成了低交联度的聚甲基丙烯酸酯高吸油性树脂，研究了交联剂用量、单体配比、反应温度和时间等对树脂性能和反应的影响，确定了合适的聚合工艺条件。     

聚(丙烯酸-co-丙烯酰胺)/高岭土复合高吸水性树脂的制备

采用N,N'-亚甲基双丙烯酰胺作交联剂,过硫酸铵作引发剂,通过水溶液聚合法制得了聚(丙烯酸-co-丙烯酰胺)/高岭土复合高吸水性树脂.研究了高岭土的添加量、丙烯酰胺用量、中和度、引发剂用量以及交联剂用量等对吸水率的影响.得到的最佳反应条件为:中和度为70%,丙烯酰胺、高岭土、引发剂和交联剂量分别为丙烯酸单体质量24%、18%、0.96%和0.09%.制得的高吸水性树脂在室温下30min每克吸蒸馏水和自来水分别约为其自身质量的890倍和290g倍.     

羽毛蛋白-聚(丙烯酸-丙烯酰胺)高吸水性树脂的制备及吸水性能

以羽毛蛋白、丙烯酸和丙烯酰胺为原料,N,N′-亚甲基双丙烯酸胺为交联剂,过硫酸铵和亚硫酸氢钠为引发剂,采用水溶液聚合法制备了羽毛蛋白-聚(丙烯酸-丙烯酰胺)高吸水性树脂。研究了羽毛蛋白用量、引发剂用量、交联剂用量以及温度对树脂吸水倍率的影响,并考察了树脂的综合吸水性能。结果表明,树脂在蒸馏水和0.9%NaCl溶液中的吸水率分别为1152g/g和69.2g/g。树脂拥有较高的吸水速率,粒径80目以上的树脂在3min以内可达到吸水溶胀平衡,并且在较宽的pH值范围(pH=5～10)内的溶液中均有较高的吸水率。     

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 ...