润滑剂分子结构及其润滑作用机理的红外发射光谱研究

在自制的“原位“摩擦装置上,利用红外发射光谱技术对润滑剂在摩擦过程中的化学行为进行跟踪测量,以期对润滑剂分子结构变化与润滑作用机理进行某些关联。实验证明,红外发射光谱技术可作为原位观测摩擦过程中化学变化的有效手段。     

Influence of fluorine-containing lubricant on properties of NR/BR rubber

K95 experimental lubricant being a product of fluorine reaction with a blend of mutually soluble poly(fluorine alcohols) and poly(fluorine esters) with molecular weight 240-900 g/mol was studied as an additive for rubber compounds based on blend of NR and BR. It was thermally stable till 270-300 °C. For comparison, it was tested simultaneously with homogenizing agent, Struktol MS40. Lubricant K95 added in a quantity of 0.5 wt% reduced the viscosity of rubber compound; it also improved compound flow in the mold. Mechanical properties of cured rubber not decrease while resistance to abrasion and fatigue increased. K95 participated in forming strong physical junctions (lower molecular weight between junctions of thermally stable network) while Struktol MS40 reduced the networking degree of rubber. As a result, it acts a multifunctional additive for NR/BR rubber.     

压力对甲烷氧化偶联均相反应的影响(英文)

在０．１～１．１ＭＰａ范围研究了压力对甲烷氧化偶联气相反应、乙烷和乙烯气相氧化反应的影响。同时考察了压力对管壁效应的影响，另外考察了不同氯化物的添加作用。     

Role of N,N-dimethyl-para-toluidine and saccharin in the radical polymerization of methyl methacrylate initiated by a redox system. II. Cumene hydroperoxide/iron saccharinate

The role of N,N-dimethyl-p-toluidine (DMPT) and saccharin as accelerators in the polymerization of methyl methacrylate initiated by the redox decomposition of cumene hydroperoxide (CHP) in the presence of iron saccharinate has been kinetically investigated. DMPT reduces ferric ions to ferrous ions, so that an equilibrium is established between the two oxidation states. With the assumption of a steady-state concentration of propagating radicals, the rate of initiation was deduced from the rate of polymerization and the kinetic orders with respect to each compound involved in the initiation step have been determined. The reaction is first-order in CHP, iron saccharinate, and saccharine and second-order in DMPT. In a proposed scheme, Fe²⁺ ions, complexed by two DMPT molecules, are much more reactive than uncomplexed Fe²⁺ and saccharin activates the decomposition of CHP by protonation of the O? O bond. This mechanism, similar to that proposed in the case of copper saccharinate, explains the synergistic effect of both accelerators. © 1994 John Wiley & Sons, Inc.     

Ammoxidation of methylpyrazine over vanadium-titanium catalysts modified by alkali additives

Vanadium-titanium catalysts modified with sodium or potassium additives (1-15 wt.% of Me₂O) have been studied in methylpyrazine ammoxidation. Introduction of the additives results in a decrease in the activity and selectivity of the catalysts due to formation of low-active phase - bronzes (MeV₆O₁₅) and vanadates (α-NaVO₃, KVO₃ and K₃V₅O₁₄). The active sites of the modified samples, similar to those in the V-Ti-O catalyst, are found to be V⁵⁺ cations strongly bound to TiO₂ and located in a significantly distorted octahedral oxygen environment. This revised version was published online in August 2006 with corrections to the Cover Date.     

Influence of additives on the structure and properties of polymers

Investigations into the transformation of hexagonal into monoclinic modification in isotactic polypropylene (iPP) were carried out. The hexagonal phase () was obtained by crystallization from a melt of iPP samples containing small molecular compounds (additives). A decline in the amount of-modification and changes of dimensions of ordering areas, perpendicular to the chain axes of iPP, was analysed at various temperatures and times of heating.The interdependence between the structure of additives and the amount of-phase occurring and also the stability of this modification during thermal treatment was observed.Obtained results indicated that only some additives play the role of moderating agents for the phase transition process.A preliminary report of this work has been presented at XIII Congress of the International Union of Crystallography (9–18 August 1984).     

Investigation of the thermal degradation of the aged pyrotechnic titanium hydride/potassium perchlorate

In previous works, the effects on the devitrification mechanism of a certain composition calcium phosphate with additives of TiO₂, SiO₂, Al₂O₃, CeO₂ have been studied. It was found that some metal oxide additives played a key role as the nucleation agent in calcium phosphate glass-ceramics, and the devitrification mechanism of calcium phosphate glass system was changed drastically by addition such as metal oxide. Hydroxyapatite (HAp), tricalcium phosphate (TCP) and β-calcium phosphate (β-CaP₂O₆) whisker are the three most biologically compatible materials to human bone in bio-ceramics field. In this work, the effect on devitrification mechanism and the physical properties of certain composition calcium phosphate glass with three above additives were investigated, and the result shown that although no fine crystalline was induced in the certain composition of calcium phosphate glass when a large amount of additive was added, but such additives play a catalyst role by lowering the activation energies of devitrification. It would supplement the mechanical properties and the biocompatibility for the calcium phosphate glasses.     

Measurement of water by oven evaporation using a novel oven design. 2. Water in motor oils and motor oil additives

The measurement of water in lubricating oils is important because water accelerates the corrosion of metal parts and bearings in motors. Some of the additives added to lubricating oils to improve their performance react with the Karl Fischer reagent (KFR) causing a positive bias in the water measurement. A new oven evaporation technique for measuring water in oils has been developed that is automated, requires less sample handling, is easily calibrated, and is capable of measuring relatively small mass fractions of water (50 mg/kg sample). A series of motor oils was analyzed with the standard KFR, a reagent that detects interfering substances that reduce iodine, and the aldehyde–ketone reagent that does not detect substances that react with methanol and form water. The oil samples were heated to 107°C and then reheated to 160°C. At both temperatures, material was measured by both KFRs, but only zinc dithiophosphate released sulfur compounds that would react with the reagent that detects interfering substances. Mass fractions of between 20 and 70% of the volatile material released at either temperature were measured with the standard KFR but not with the aldehyde–ketone reagent. These results demonstrate that there are a number of sources of positive bias in the measurement of water in motor oils and that the standard KFR cannot be used to measure water in motor oils and motor oil additives. These results also indicate that some of the material reacts with methanol to form water. Finally, these results suggest that some of the material that is volatile at 160°C and not at 107°C may be water that is physically occluded or may be substances that react with diethyleneglycol monomethylether to produce water.     

五彩湾煤灰的烧结特性及不同添加剂的影响规律

采用热机械分析仪、高温热台显微镜、XRD及FactSage软件相结合的方法,研究了五彩湾煤灰的烧结特性及不同添加剂的影响规律。结果表明,沙子(SiO_2含量约为80%)和煤矸石(SiO_2含量为54%,Al_2O_3含量为42%)能改变煤灰的烧结特性(烧结温度和烧结速率),但不同添加剂改变的程度不同。添加10%的沙子能使烧结温度提高70℃,而0-15%煤矸石不能使烧结温度升高。此外,烧结速率随添加剂增多而减小,烧结区间随添加剂增多而延长。进一步研究表明,添加剂能够改变煤灰初始液相温度、组成、含量、煤灰中硫酸盐的分解温度及初始液相温度从而改变煤灰的烧结特性。