α-MSAN共聚物的组成对PMMA/α-MSAN共混物相容性的影响

采用乳液聚合技术合成了一系列配比不同的α-甲基苯乙烯和丙烯腈共聚物粉料（α-MSAN）,将其与聚甲基丙烯酸甲酯(PMMA)熔融共混,利用透射电镜(TEM)和动态力学黏弹谱仪(DMA)考察了PMMA/α-MSAN共混物的相容性。结果表明,当α-MSAN共聚物中丙烯腈含量为15 %～25 %时,α-MSAN与PMMA形成相容体系,其相容性随丙烯腈含量的增加而变好;当丙烯腈含量大于30%时,共混物均为不相容体系。     

PVC/α-MSAN共混物的性能研究

采用机械共混法制备了PVC与α-甲基苯乙烯类-丙烯腈共聚物(α-MSAN)共混材料,探讨了α-MSAN用量对共混材料的力学性能、耐热性能和加工性能的影响。结果表明:α-MSAN可以改善共混材料的耐热性能和加工性能;随着α-MSAN用量的增多,共混材料的热变形温度(最大弯曲正应力分别为1.80 MPa和0.45MPa)、拉伸强度、弯曲强度、弯曲模量和熔体流动速率上升,而冲击强度、断裂伸长率下降。综合考虑性能与成本等因素,α-MSAN用量为30份最佳,此时,共混材料的热变形温度由72.4℃提高至81.6℃(最大弯曲正应力为1.80 MPa)。     

The impact of the discovery of the polymerization of the α-olefins on the development of the stereospecific polymerization of vinyl monomers

After a short survey of the first indications on the existence of stereoregularity in the main chains of the vinyl polymers, the first syntheses of stereoregular poly(vinylethers) and polystyrene are briefly summarized. The difficulties encountered in the early investigations of the propylene polymerization by the CoO/MoO₃/Al₂O₃ and CrO₃/SiO₂/Al₂O₃ catalysts are considered and the isolation and identification of a crystalline component in the mixture of diastereomeric macromolecules thus obtained, are discussed. The results obtained by different research groups, independently investigating the stereospecific polymerization of vinyl monomers, are compared and finally an attempt is made to explore the origin of the very rapid progress made in this field by Natta and coworkers in connection with their discovery of the stereospecific polymerization of α-olefins with the ‘Ziegler-Natta catalysts’.     

DOP含量对PVC/α-MSAN共混物相容性的影响

在PVC与α-甲基苯乙烯-丙烯腈共聚物(α-MSAN)配比不变的条件下,采用动态力学分析仪和扫描电子显微镜,系统地分析了DOP含量对PVC/α-MSAN共混体系相容性的影响。结果表明:1PVC/α-MSAN共混物是相容的均相体系;2少量DOP的加入不足以破坏PVC/α-MSAN共混物的均相体系;3随着DOP含量的增加,其对PVC/α-MSAN均相体系中分子作用力的破坏程度加大,体系的相分离程度加大;4随着DOP含量的增加,PVC/α-MSAN共混物链段运动的分散性增大,分子链断裂,分子链的柔韧性增加,表现出很好的柔韧性。     

The role of the symmetry and the flexibility of the anion on the characteristics of the nanostructures and the viscosities of ionic liquids☆

The transport properties of ionic liquids (ILs) are crucial properties in view of their applications in electrochem-ical devices. One of the most important advantages of ILs is that their chemical–physical properties and conse-quently their bulk performances can be well tuned by optimizing the chemical structures of their ions. This will require elucidating the structural features of the ions that fundamentally determine the characteristics of the nanostructures and the viscosities of ILs. Here we showed for the first time that the“rigidity”, the order, and the compactness of the three-dimensional ionic networks generated by the anions and the cation head groups determine the formation and the sizes of the nanostructures in the apolar domains of ILs. We also found that the properties of ionic networks are governed by the conformational flexibility and the symmetry of the anion and/or the cation head group. The thermal stability of the nanostructures of ILs was shown to be con-trolled by the sensitivity of the conformational equilibrium of the anion to the change of temperature. We showed that the viscosity of ILs is strongly related to the symmetry and the flexibility of the constitute ions rather than to the size of the nanostructures of ILs. Therefore, the characteristics of the nanostructures and the viscosities of ILs, especially the thermal stability of the nanostructures, can be fine-tuned by tailoring the symmetry and the conformational flexibility of the anion.     

Dependence of the Time‐Space Structure of the Chemical‐Reaction Zone on the Initial Density of the Explosive

The results of a study of the chemicalreaction zone structure for a number of high explosives (HEs) are discussed. It is found that an increase in the initial density of the HEs leads to a structural change in the chemicalreaction zone involving elimination of the Von Neumann spike at the critical density point. Conversely, as the initial density of the explosive decreases, the ratios of the gasdynamic parameters (in particular, mass velocities) at the Von Neumann point to the same parameters at the Jouguet point increase. It is shown that to explain the indicated regularities, one does not need to invoke the assumption of an increasing contribution of the exothermic decomposition of the HE the shock. The results can be explained within the framework of classical Zeldovich–Von Neumann–Döring theory with an ordinary shock at the detonationwave front and, hence, with a nearly zero contribution to the total energy release in the chemical reaction zone.     

Investigation of the effect of minor ions on the stability of β-C2S and the mechanism of stabilization

In this paper the effect of minor ions on the stability of β-C₂S has been studied. It is discovered that the effect of minor ions on the stability of β-C₂S is closely related to the polarization ability of the ions. According to this the authors propose a new judgement, the ion polarization ability judgement, by which we can determine if minor ions have the stabilizing affect on β-C₂S. The judgement is that those ions, either having smaller polarization ability than that of calcium ion or greater than that of silicon ion, all have the ability to effect the stability of β-C₂S. This judgement is more practical than those made by other authors. In this paper a new mechanism about the stabilization has been described on the basis of applying the principles of thermodynamics and dynamics of the transformation of solid phases in accordance with the above judgement.     

PVC/α-MSAN/ASA共混物的结构与性能研究

采用乳液聚合技术合成了一系列不同核壳比的丙烯酸丁酯-苯乙烯-丙烯腈接枝共聚物(ASA)和组成为69/31的α-甲基苯乙烯-丙烯腈共聚物(α-MSAN)。将ASA接枝共聚物与聚氯乙烯(PVC)和α-MSAN熔融共混制备了PVC/α-MSAN/ASA共混物,利用扫描电子显微镜(SEM)和差示扫描量热仪(DSC)对该共混体系的性能与形态进行了表征。结果表明:随着体系中橡胶含量的增加,PVC/α-MSAN/ASA共混物的冲击强度先增大后减小,拉伸强度则逐渐降低,其中橡胶含量为15%的共混物具有较高的韧性;当ASA接枝共聚物的核壳比逐渐增大时,共混物的冲击强度先增大后减小,而拉伸强度基本不变;此外,共混试样的断面形态与其力学性能相符。     

Parametric Analysis of the Simplest Model of the Theory of Thermal Explosion—the Zel''dovich—Semenov Model

Parametric analysis is performed for the Zel'dovich–Semenov model, a basic model of the theory of thermal explosion that describes the dynamics of an exothermic reaction with arbitrary kinetics in a continuous stirred tank reactor. Particular attention is given to the cases of first and nthorder reactions, oxidation reaction, and reaction with arbitrary kinetics. Parametric dependences of steady states on dimensionless parameters, curves of multiplicity and neutrality of steady states, and parametric and phase portraits of the system are constructed. Regions of multiple steady states and selfoscillations and a region of technological safety are distinguished.     

Effect of the fractional composition of the solid components of coal–water fuel on the characteristics of ignition and combustion

The experimental results of studies of the ignition and subsequent combustion processes of the single drops of organic coal–water fuels (OCWFs) arranged on the junction of a quick-response thermocouple (thermal inertia, <1 s) in an atmosphere of heated (600–1000 K) air are presented. The particles of 2B brown coal and D coal, water, and oils of different types (turbine, motor, and transformer oils) were used as the main OCWF components. The effect of the degree of grinding (fineness) of the solid fuel components of OCWFs on the following integral characteristics of the ignition and combustion of prepared fuel compositions was established: the delay times of ignition and complete combustion. A decrease in the delay times of ignition and complete combustion with decreasing the degree of grinding was detected (in a range of 40–200 μm used as an example). The reasons and special features of the influence of this factor on the integral characteristics of the test processes were recognized.     

Influence of the temperature dependence of the thermophysical properties of coal–water fuel on the conditions and characteristics of ignition

The results of an experimental study and mathematical simulation of the ignition of coal–water fuel (CWF) particles, the main thermophysical characteristics of which (thermal conductivity (λ), heat capacity (C), and density (ρ)) depend on temperature, are reported. Based on the results of the numerical study, the influence of changes in the thermophysical properties upon the heating of the main bed of fuel on the conditions and characteristics of its ignition was analyzed. The ignition delay times (t _i) of CWF particles were determined under the typical furnace conditions of boiler aggregates. As a result of the mathematical simulation of the process of CWF ignition, it was established that the temperature dependence of thermophysical characteristics can exert a considerable effect on the characteristics and conditions of ignition. In this case, it was found that the ignition of coal–water drops is possible under the conditions of their incomplete dehydration. A good agreement of the theoretical ignition delay times of the CWF particles and the experimental values of t _i was established.     

the determination of rig

per or not. For many years, scientists in the world have done a lot of research work in this field. As opinions vary, no unanimous conclusion can be drawn.In this paper, the physical concept of each items in rigidity is analysed first, an     

Effect of the processing on the production of cordierite–mullite composite

In this study, effect of process on the production of cordierite–mullite composite was studied. For this reason two different processing methods were used in the production of cordierite–mullite composites. In first process, in situ cordierite–mullite composites were produced from cordierite and mullite layers which were formed by using aqueous tape casting method. In second one, composite was produced by addition of pre-produced mullite powders (in different weight percents, 0–30) into cordierite starting powders. The results show that the addition of pre-sintered mullite powders to the cordierite slip has more effect on densification behavior and mechanical properties of composites than layered production method.     

Influence of the nature of the activating molecules on the catalytic activity of cobalt—molybdenum/alumina catalysts

The effectiveness of the activation of a commercial CoMo/Al₂O₃ catalyst was evaluated using five different sulphiding agents (carbon disulphide, dimethyldisulphide, butanethiol, thiophene and hydrogen sulphide) at high pressure (3 MPa) in the 300–450°C temperature range. The results indicate that the behaviour of the cobalt—molybdenum catalysts depends strongly on the nature of the activating molecule as well as the pretreatment temperature. The catalyst exhibited two different patterns, below and above 400°C. At 300°C, differences in the degree of sulphidation and in activities were observed when using different activating molecules. The most efficient of the sulphiding agents used was butanethiol while the least efficient one was thiophene. The activity of the catalyst was a maximum when carbon disulphide was used at 350°C or the other sulphiding agents at 400°C. We attributed the differences of effects of the various molecules to coupling effects between reduction and sulphidation reactions. Under the activation giving excellent activities, the coupling effect is optimal. Using carbon disulphide or thiophene at temperatures higher than 400°C, a catalyst with strongly decreased activity was produced. This behaviour is attributed to coke formation during sulphidation.     

Effect of Self-Assemblies on the Dynamics of the Briggs–Rauscher Reaction

The study involves the dynamic evolution of the Briggs–Rauscher (BR) reaction in the presence of various surfactants—SDS (sodium dodecyl sulphate) as anionic, CTAB (cetyl trimethylammonium bromide) as cationic and TritonX‐100 [4‐(1,1,3,3‐(tetramethylbutyl) phenyl polyethylene glycol] as a neutral one in single as well as mixed mode conditions (SDS + TX‐100 and CTAB + TX‐100). The reaction has been monitored potentiometrically at 30 °C under CSTR conditions. These surfactants affect the reaction dynamics to an extent which depends on the nature and concentration of the surfactant and the formation of their self‐assemblies. The experimental findings indicate that the oscillatory behavior of the BR reaction in the presence of surfactants is due to the efficacy of organized surfactant assemblies to selectively distribute the key species involved in the reaction, and their interaction with the counter ions in cases of ionic micelles. The study reveals that the evolution of oscillatory behavior is a characteristic feature of the surfactant.     

Effect of the Location of the Detonation Initiation Point and the Position of the Air–Fuel Cloud on Explosion‐Field Parameters

The effect of the location of the initiation point on explosionfield parameters is studied numerically using as an example the detonation of a stoichiometric mixture of propane with air. The shape of the cloud of the mixture (toroid) and the ratio of its dimensions in calculations are typical of the volumes of air–fuel mixtures formed in accidents. The effect of the initiation point location within the cloud cross section was studied with variation in the position of the lower edge of the cloud above the underlying surface.     

Modernization of oil refineries as the basis for the development of the Russian oil refining industry in the period of 2010–2020

Ways of developing and modernizing Russian oil refineries are considered on the basis of an analysis of the presentations of Russian and foreign companies at the 10th Russian and CIS Refining Technology Conference (RRTC) held by Euro Petroleum Consultants in Moscow on September 23–24, 2010. It is shown that the main trends in the development of the Russian oil refining industry with the purpose of overcoming the current economic crisis are the rational use of production facilities, the modernization of existing plants to increase the depth of processing and the profitability of production, satisfying the growing demand for motor fuels (especially diesel) and improving their quality to meet the parameters of eurostandards, increasing the conversion of the processing of oil at oil refineries, reducing the consumption of energy, and improving the process control and optimization systems at existing plants to increase their efficiency and minimize the environmental risks in operating plants. The development of hydrogenation processes that allow the synthesis of high-quality products from cheap sour crude oil or the qualified preparation of raw materials for the process of catalytic cracking must now become the main direction of oil refining in Russia and CIS countries. Oil residue processing technologies (e.g., hydrogenation processes, catalytic cracking, new and improved catalysts for hydrocracking, catalytic cracking, hydrotreatment of heavy oil residues; and hydrogen synthesis technologies) are discussed.