磺酸型水性聚氨酯胶粘剂的制备及性能研究

采用预聚体合成法,以二羟甲基丙酸(DM-PA)和2,4-二氨基苯磺酸钠(SDBS)为亲水扩链剂,制备了一种水性聚氨酯预聚体,再将高分子乳液乙烯-醋酸乙烯酯(EVA)与去离子水均匀混合对其乳化,制得固含量高达50%磺酸型水性聚氨酯鞋用胶粘剂。利用红外光谱对SDBS和聚氨酯的结构进行了表征,证实了SDBS作为亲水扩链剂引入聚氨酯链上。研究了SDBS用量对胶粘剂的剥离强度,耐热性及稳定性的影响。当SDBS用量从0%增加到2.5%时,皮革初期剥离力由20.98N上升至89.23N,其耐热性和稳定性也有所增强。透射电镜图片显示,与EVA共乳化后的磺酸型水性聚氨酯(SWPU)乳液分散均匀,呈圆球状。     

无有机溶剂法合成水性聚氨酯-聚丙烯酸酯胶粘剂

采用羧酸型亲水扩链剂二羟甲基丁酸(DMBA)以及磺酸型亲水扩链剂2,4-二氨基苯磺酸钠(SDBS),选用乙烯基单体作为聚氨酯(PU)预聚合的连续相,制备了稳定的无挥发性有机溶剂(VOC)水性聚氨酯-聚丙烯酸酯(SPUA)胶粘剂。利用傅里叶变换红外光谱(FT-IR)对改性前后PU的分子结构进行分析对比,并考察了亲水扩链剂用量、聚丙烯酸酯(PA)含量对胶粘剂的耐水性、稳定性和力学性能的影响。结果表明。当SDBS含量为2%(wt,质量含量,下同),DMBA为4.5%,PA为25%时,SPUA胶粘剂的耐水性、稳定性和力学性能最佳,固含量可达43%。透射电镜(TEM)照片表明,SPUA乳胶粒呈圆球状,乳液平均粒径分布均匀。     

新型可紫外光固化水性聚氨酯的制备与表征

以异佛尔酮二异氰酸酯(IPDI)、聚酯二元醇Pol-1256、二羟甲基丙酸(DMPA)为主要原料,采用预聚体法制备了水性聚氨酯预聚体,然后用自制的扩链剂对该预聚体进行扩链,并用丙烯酸羟乙酯(HEA)对扩链后的预聚体进行封端,最后中和乳化,制备了高紫外光(UV)固化基团含量的可UV固化水性聚氨酯乳液。采用FTIR对产物的结构进行了鉴定,利用旋转流变仪对分散体的流变性能进行了表征,通过TGA分析了UV固化膜的耐热性能,并对其拉伸性能进行了测试。研究结果表明:所制扩链剂符合预期结构特征,所得产物符合可UV固化的水性聚氨酯结构特征;乳液呈现出剪切变稀的特征,属于假塑性流体;UV固化膜具有良好的耐热性能,同时具有较高的断裂伸长率和良好的拉伸强度。     

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.     

胶原蛋白改性水性聚氨酯的合成及表征

以异佛尔酮二异氰酸酯(IPDI)与聚四氢呋喃醚二醇(PTMG-2000)为原料,二羟甲基丙酸(DMPA)为扩链剂,三乙胺为中和剂制备聚氨酯预聚体。采用碱水解法水解明胶,制备胶原蛋白水解液,作为后扩链剂,在乳化分散的同时进行链增长,得到胶原蛋白改性水性聚氨酯。研究胶原蛋白改性水性聚氨酯合成过程中R值、DMPA用量对其性能的影响,采用红外(FT-IR),差热分析(DSC)等分析对制备的胶原蛋白改性水性聚氨酯胶膜进行分析。在R值为1.30,DMPA用量为0.065mol条件下,制得的胶原蛋白改性水性聚氨酯膜的各项性能较好,结晶趋势增加,耐水性得到改善,平均粒径68.33nm,延伸率为554.5%,抗张强度为5.51N/mm。     

亲疏水扩链剂比例对XDI型水性聚氨酯性能的影响

为了研究亲水/疏水性扩链剂比例对芳脂族的二异氰酸酯XDI型水性聚氨酯性能的影响,文中采用聚酯多元醇为软段,间苯二亚甲基二异氰酸酯(XDI)、亲水性的二羟甲基丙酸(DMPA)和1,4-丁二醇(BDO)扩链剂为硬段,合成了XDI型水性聚氨酯(XWPUs),研究了DMPA/BDO比例对聚氨酯乳液的粒径、耐水性、力学性能和耐热性的影响。研究发现,随着DMPA/BDO的比例从0.74到6.14逐渐增大,XWPUs聚氨酯乳液粒径从71.66nm增加到159.40nm,微相分离程度增加,样品薄膜的吸水率从1.87%增到12.17%。XWPUs薄膜的拉伸强度较高,均在20 MPa左右,并具有较高的耐热性,失重5%时温度在280~250℃之间,但耐热温度随着DMPA/BDO值的增加而降低。XDI型水性聚氨酯结构中适宜的亲水/疏水性扩链剂比例,既能保证乳液的粒径和稳定性,又能使样品具有较好的耐水性、力学性能和耐热性。     

N,N-二甲基乙醇胺在本体消光型水性聚氨酯中的作用EI北大核心CSCD

本体消光型水性聚氨酯可以避免外加消光剂带来的弊端,是一种新型的功能性环保涂料。文中以异氟尔酮二异氰酸酯、聚己二酸丁二醇酯多元醇、二羟甲基丙酸(DMPA)、三羟甲基丙烷为预聚体原料,三乙胺和N,N-二甲基乙醇胺(DMEA)为中和剂,乙二胺基乙磺酸钠和水合肼为后扩链剂,采用预聚体分散法制备出水性聚氨酯(WPU)乳液。对不含DMEA的WPU样品系列与含有DMEA的WPU样品系列的消光性能进行了对比研究。结果表明,当DMEA的质量分数为1%时,不同DMPA用量的WPU乳液的平均粒径均保持在2100 nm左右,且粒径分布较窄,DMPA用量对其粒径和粒径分布影响不大;含有DMEA的WPU涂膜透过率相对有所降低,其表面凸起由球状颗粒紧密堆积而成,测得表面光泽度(60°)低于1。     

两性离子型水性聚氨酯构效关系研究

以异佛尔酮而异氰酸酯、含磺酸基的聚酯二元醇、聚己二酸丁二醇酯二醇、1,4-丁二醇为原料,以叔胺型扩链剂为亲水扩链剂,将含有阴离子磺酸基的水溶性聚酯多元醇引入到阳离子性的水性聚氨酯分子结构中,制备出含有阴、阳两性离子型聚氨酯。利用红外光谱、透射电子显微镜、激光粒度分析仪、原子力显微镜、扫描电子显微镜和乳液电位分析等手段对两性离子乳液进行了分析表征,结果发现两性离子水性聚氨酯在不同pH值环境下具有不同的电离状态,乳液在酸性条件下,zeta电位为50.4mV,呈现阳离子性,乳液在碱性条件下,zeta电位为-48.3mV,乳液显示为阴离子性,说明水性聚氨酯具有阴、阳两性特征。因此两性离子型水性聚氨酯较单一离子特性的水性聚氨酯在烘干过程中更容易产生胶粒与胶粒间作用力,能够表现出更大初粘性,更适合制备水性聚氨酯粘合剂。     

N,N-二甲基乙醇胺在本体消光型水性聚氨酯中的作用

本体消光型水性聚氨酯可以避免外加消光剂带来的弊端,是一种新型的功能性环保涂料。文中以异氟尔酮二异氰酸酯、聚己二酸丁二醇酯多元醇、二羟甲基丙酸(DMPA)、三羟甲基丙烷为预聚体原料,三乙胺和N,N-二甲基乙醇胺(DMEA)为中和剂,乙二胺基乙磺酸钠和水合肼为后扩链剂,采用预聚体分散法制备出水性聚氨酯(WPU)乳液。对不含DMEA的WPU样品系列与含有DMEA的WPU样品系列的消光性能进行了对比研究。结果表明,当DMEA的质量分数为1%时,不同DMPA用量的WPU乳液的平均粒径均保持在2100 nm左右,且粒径分布较窄,DMPA用量对其粒径和粒径分布影响不大;含有DMEA的WPU涂膜透过率相对有所降低,其表面凸起由球状颗粒紧密堆积而成,测得表面光泽度(60°)低于1。     

正丁胺为扩链剂合成水性聚氨酯皮革涂饰剂

采用异佛尔酮二异氰酸酯(IPDI)、二羟甲基丙酸(DMPA)、聚四氢呋喃(PTMG)为原料制备聚氨酯预聚体,分别以乙二醇(EG)、乙二胺(EN)和正丁胺(n-butylamine)为扩链剂制备了水性聚氨酯皮革涂饰剂,研究了该涂饰剂所成膜的力学性能、断裂伸长率和吸水性。结果表明,以正丁胺为扩链剂制备的水性聚氨酯膜的断裂伸长率最好,高达1454%;其玻璃化转变温度可达-82℃,耐水性也比用其它两种扩链剂合成的产品好。     

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...     

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.     

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.     

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.     

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.     

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.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.