有机蒙脱土与白炭黑复合填充三元乙丙橡胶性能研究

采用溶液插层法分别制备了含乙烯基的有机蒙脱土(VMMT)和不含乙烯基的有机蒙脱土(OMMT),并通过与三元乙丙橡胶(EPDM)机械共混方法制备了VMMT/EPDM、OMMT/EPDM两种纳米复合材料,对复合材料的力学性能和气体阻隔性能进行了研究。实验发现:当添加相同份数有机蒙脱土时,VMMT/EPDM复合材料的力学性能和气体阻隔性能优于OMMT/EPDM复合材料;当有机蒙脱土添加量为5份时,OMMT/EPDM的拉伸强度提高了60%、100%伸长模量提高了68%,N2透气率降低了29%;当有机蒙脱土添加量为7份时,VMMT/EPDM的拉伸强度提高了99%、100%伸长模量提高了157%、N2透气率降低了52%。结果表明:通过含乙烯基官能团的有机插层剂改性后,有机蒙脱土/EPDM纳米复合材料的力学性能和气体阻隔性能显著提高。     

蒙脱土填充木塑复合材料的弯曲性能和蠕变特性

对蒙脱土进行有机插层改性制得有机蒙脱土(OMMT),用硅烷接枝木粉制备了有机蒙脱土/木粉/聚氯乙烯(OMMT/WF/PVC)纳米复合材料。加入的接枝木粉与OMMT分散在界面上起增强作用,有助于提高复合材料性能。用质量分数1.5%的偶联剂处理木粉,添加质量分数1.5%的OMMT时,复合材料的弯曲性能和抗蠕变性最好。用KWW模型和广义Voigt模型分析了蠕变曲线。     

聚氨酯/聚甲基丙烯酸甲酯/有机蒙脱土纳米复合材料的制务、结构与性能

首次将插层纳米复合技术与互穿聚合物网络（IPN）技术相结合,通过同步插层聚合法制备了聚氨酯/聚甲基丙烯酸甲酯/有机蒙脱土（PU/PMMA/OMMT）纳米复合材料.XRD、SEM、TGA等研究表明,在聚氨酯/有机蒙脱土（PU/OMMT）体系中蒙脱土以40～700 nm的团聚体不均匀地分散在聚氨酯基体中,且部分蒙脱土被插层,其层间距增加了0.95nm,体系为插层型纳米复合材料.PU/PMMA/OMMT体系中蒙脱土以20～80nm的粒子分布于聚合物基体中,且蒙脱土的插层效果显著,是PU/OMMT体系的2.5倍,形成了插层型纳米复合材料.同时,蒙脱土的加入使得聚氨酯和聚甲基丙烯酸甲酯的互穿聚合物网络（PU/PMMA-IPN）体系中PU相与PMMA相间相分离更明显,塑性相畴粒子尺寸显著增加,且各相中两组分相互作用加强,分布更均匀.PU/PMMA/OMMT纳米复合材料的热稳定性高于其他材料.同时对其力学性能进行了研究,发现其力学性能明显优于聚氨酯、基于聚氨酯和PU/PMMA-IPN和PU/OMMT纳米复合材料.     

有机蒙脱土插层改性丁腈橡胶纳米复合材料

用丁腈橡胶(NBR)、自制有机蒙脱土(OMMT)通过机械共混方法制备了丁腈橡胶/有机蒙脱土(NBR/OMMT)复合胶。研究了有机蒙脱土的用量(0 phr~30 phr)对复合胶的微观结构、物理性能、力学性能、耐热性能、耐油与耐溶剂性能、耐紫外老化性能的影响。研究表明,有机蒙脱土的加入缩短了正硫化时间,少量的OMMT尤为明显;X射线衍射显示在OMMT(10 phr~25 phr)时,丁腈橡胶与有机蒙脱土形成了良好的纳米插层结构;有机蒙脱土的加入有助于提高复合胶的物理性能、耐热性能、耐油性能、耐溶剂性能,热重分析显示添加30 phr有机蒙脱土比未添加蒙脱土的胶料Tmax提高17.4℃,且25 phr时复合胶综合性能最佳。     

聚乳酸/有机蒙脱土复合材料制备及性能研究

目的测试聚乳酸/有机蒙脱土复合材料的性能并进行研究。方法通过溶液插层法制备聚乳酸(PLA)/有机蒙脱土(OMMT)纳米复合材料,对材料的热稳定性能、流变学性能和力学性能等进行测试分析。结果 PLA,PLA/OMMT(质量分数为3%)和PLA/OMMT(质量分数为6%)的结晶度分别为13.01%,15.43%,18.26%,热分解温度分别为336.36,343.55,345.14℃,在336.36℃时残余质量分数分别为82.45%,85.57%,87.58%。当温度一定时,频率增大,储能模量和耗能模量也随之增大,在测试频率范围内,耗能模量大于储能模量。几种材料均呈现剪切变稀效应,且随着频率的增大,有机蒙脱土纳米含量越多的复合材料其粘度也增大且较为显著。随着OMMT含量的增加,拉伸模量得到提高,拉伸强度基本不受影响,伸长率先提高再降低。结论同聚乳酸相比,纳米复合材料的热稳定性能得到提高,结晶度增大,流变学性能和拉伸力学性能得到提高。     

有机蒙脱土/丁腈橡胶-聚氯乙烯隔声复合材料的制备及性能

轻质隔声材料一直是隔声功能材料的研究热点.本研究以NBR-PVC为基料,通过纳米有机蒙脱土(OMMT)填充改性制备了有机蒙脱土/丁腈橡胶-聚氯乙烯隔声材料,并探讨了纳米有机蒙脱土添加量对材料面密度、力学性能、阻尼性能和隔声性能的影响.实验结果表明,当OMMT质量含量为3.73%时,OMMT/NBR-PVC复合材料的弹性模量、拉伸强度、断裂伸长率及阻尼性能综合最佳,其隔声指数可达32.6 dB.     

阻燃聚丙烯/蒙脱土纳米复合材料的制备及性能研究

通过熔融挤出法制备出了膨胀阻燃剂/聚丙烯/有机蒙脱土(IFR/PP/OMMT)阻燃纳米复合材料,XRD分析表明,蒙脱土的层间距扩大,复合材料进入其层闻,形成了纳米复合材料;结果表明,当复合材料中IFR含量为25%时,加入4%的OMMT体系的缺口冲击强度为7.8kJ/m2,拉伸强度为25.3MPa,弯曲模量为1520MPa,极限氧指数(LOI)提高到26,而耐热性也得到提高,复合材料的综合性能最好;通过对膨胀炭层的SEM分析表明,OMMT可以使炭层更加紧密,阻燃性能进一步提高.     

乳液插层法制备天然胶/蒙脱土复合材料的性能

先用乳液插层法制共沉胶,再通过熔融混炼法制备有机化蒙脱土(OMMT)/天然胶乳复合材料。研究复合材料的结构、拉伸性能、硬度、热性能。结果表明:OMMT/天然胶乳形成了插层型纳米结构。与天然橡胶相比,OMMT/天然胶乳复合材料的拉伸强度、硬度增加。当OMMT含量为6%时,能获得拉伸强度、断裂伸长率较优的材料。该OMMT/天然胶复合材料的力学性能超过白碳黑对材料的增强效果。     

原位乳液插层法制备PBA/OMMT纳米复合母料及其在ABS中的应用

通过原位乳液插层法制备高有机蒙脱土(OMMT)含量的聚丙烯酸丁酯/有机蒙脱土(PBA/0MMT)纳米复合物,将其作为母料与ABS进一步熔融插层制得力学性能良好的ABS/OMMT纳米复合材料,并通过XRD、TGA和TEM等对材料进行了表征.结果表明:制得的PBA/OMMT母料为插层型纳米复合物,OMMT片层间距从2.38nm增大到3.85nm;采用母料法制备ABS/OMMT纳米复合材料,ABS链段易插层进入OMMT层间,使OMMT片层在ABS基体中达到剥离并以纳米尺度均匀分散,较好地保持了ABS的缺口冲击强度.     

OMMT/EP/CF三元复合材料的制备及耐热性能研究

为了提高碳纤维复合材料的热学性能及高温力学性能,通过有机化蒙脱土改性环氧树脂(EP)制备了有机化蒙脱土/环氧树脂/碳纤维(OMMT/EP/CF)三元复合材料,研究了有机化蒙脱土在环氧树脂中的插层效果,有机化蒙脱土的类型与加入份数对OMMT/EP/CF三元复合材料力学性能及热学性能的影响,同时研究了温度对OMMT/EP/CF三元复合材料的力学性能的影响.研究表明,加入了有机化蒙脱土后,复合材料的力学性能及热学性能均有较大幅度的提高,同时还表明随着温度的升高,复合材料的性能逐渐降低.     

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...     

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.     

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.     

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.……     

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.     

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.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.