氟硅油用作高温航空润滑油的研究

对氟硅油的性能进行了研究,主要包括热氧化安定性、润滑性和黏温性能等.结果表明:氟硅油的热氧化稳定性温度可达250℃；通过分子结构中引入了Cl元素,其润滑性能得到明显的提高；此外还具有优异的黏温性能和低温性能.该油的最高使用温度比酯类油提高了50℃以上.     

添加热氧化鳞片石墨对高炉炭砖显微结构和性能的影响

首先采用热氧化方法对鳞片石墨进行处理得到热氧化鳞片石墨,以部分取代高炉炭砖中电煅煤细粉的方式将热氧化鳞片石墨引入到高炉炭砖中,借助X射线衍射仪、场发射扫描电镜以及激光导热仪等研究了热氧化鳞片石墨的添加对高温焙烧后高炉炭砖物相组成、显微结构、导热系数和抗铁水溶蚀等性能的影响。结果表明:与鳞片石墨相比,热氧化鳞片石墨的氧化活化能低,具有更高的反应活性。添加热氧化鳞片石墨在高温下促进了炭砖基体内原位陶瓷相SiC晶须的生成,从而优化了炭砖的微孔结构,提高了炭砖的耐压强度、导热系数和抗铁水溶蚀性能;但是热氧化鳞片石墨添加量过大时,炭砖的导热系数提高不明显,并且小于1μm孔的容积率和耐压强度降低。对比引入相同量的天然鳞片石墨试样,添加热氧化鳞片石墨的炭砖耐压强度、导热系数和抗铁水溶蚀性能更优。当热氧化鳞片石墨的添加量为6%～8%(质量分数)时,高炉炭砖的综合性能最优。     

航空润滑油的氧化安定性

用腐蚀和氧化安定性试验研究了航空润滑油的氧化安定性。对国内的酯类航空润滑油及俄罗斯相同等级产品的氧化安定性进行了对比评定。     

氟硅油的热氧化安定性

研究和讨论了国产含γ-三氟丙基硅氧烷氟硅油基础油的抗氧化性能及不同种类添加剂的作用。结果表明，金属特别是铁的金属有机化合物可以提高氟硅基础油的抗氧化性能，其中硅醇铁化合物与氟硅油还具有较好的相容性。     

氟硅油的合成及应用

氟硅油具有优良的耐油、耐溶剂及耐候性。介绍了氟硅油制备过程中的单体合成、分离及水解、开环共聚,论述了氟硅油及其二次产品的应用,展望了其发展前景。     

氟和碳酸根共替代对羟基磷灰石性能的影响研究

以湿化学法制备了碳氟共替代羟基磷灰石(CFHA)。通过X射线衍射(XRD)、高温膨胀仪、扫描电镜(SEM)和电子万能试验机研究了氟和碳酸根共替代对CFHA高温热稳定性、高温烧结性能、热膨胀系数和抗折强度的影响。结果表明,湿CO2保护气氛有利于碳酸根的热稳定性,失重主要取决于碳酸根含量,碳氟替代对碳酸根的分解温度无明显影响。碳酸根替代促进烧结,而氟替代不利于烧结。碳酸根和氟的共替代能够降低CFHA的高温热膨胀系数(CET)和提高抗折强度。     

喷气燃料高热安定性添加剂定量检测研究

高热安定性添加剂能有效提升喷气燃料的热氧化安定性,其用量大小会对喷气燃料的质量和使用性能产生影响。采用气相色谱/质谱联用技术研究了定量检测高热安定性添加剂含量的可行性,发现高热安定性添加剂中抗氧剂单峰峰高与喷气燃料烃组分最高峰峰高的比值,与添加剂含量具有较好的线性相关性,当添加剂含量在0.125~1g/L时,两者的线性相关系数可以达到0.99927,通过建立不同含量添加剂的校准关系曲线,可实现喷气燃料中添加剂含量的精确测定。     

高强度耐热性加成型高温硫化硅橡胶的研究

本文讨论了多苯(基)苯基乙烯基硅油对加成型高温硫化硅橡胶物理机械性能及其耐空气老化性能的影响。     

热氧化多孔硅制备及其干涉特性研究

采用电化学阳极氧化法制备彩色薄层多孔硅,经高温热氧化处理后形成稳定的热氧化多孔硅.研究电化学制备条件对热氧化多孔硅的干涉效应和光学厚度的影响,分析热氧化处理前后多孔硅的稳定性.结果表明,在可见光波长范围内,所制备的热氧化多孔硅反射光谱出现一定规律性的干涉条纹,表现出明显的反射干涉现象;随阳极氧化时间、电流密度和HF浓度增大,热氧化多孔硅光学厚度呈增大趋势,当阳极氧化时间为30s、电流密度为520mA/cm2、v(HF):v(C2H5OH)为2:1～5:2时,制备的热氧化多孔硅干涉条纹均匀且光学厚度较大;热氧化处理后,多孔硅结构中的Si-Hx键被Si-O键所取代,其反射干涉特性非常稳定.     

氧化钕改性树脂传递模塑聚酰亚胺树脂的热氧化稳定性

采用纳米氧化钕(Nd₂O₃)为热氧化稳定性的改性剂,利用机械共混方法制备了氧化钕改性的树脂传递模塑(RTM)聚酰亚胺低聚物,经375℃高温固化获得了改性RTM聚酰亚胺树脂,研究了氧化钕含量对RTM聚酰亚胺树脂的热氧化稳定性、工艺性能和力学性能的影响。结果表明,一定量氧化钕的加入能够显著提高RTM聚酰亚胺树脂的热氧化稳定性,随着氧化钕含量增加,热氧化稳定性和拉伸强度先升高后下降,当氧化钕填充含量为1%时,RTM聚酰亚胺树脂在350℃老化150 h的老化失重率降低幅度可达64%,拉伸强度则提高了42%,同时对流变性能影响较小,显示了良好的改性效果。     

Synthesis and characterization of antioxidants and detergent dispersant based on some polyisobutylene copolymers

Polyisobutylene succinic anhydride-urea/polyamines (PIBSA) copolymers were synthesized as potential antioxidants and detergent dispersant agents for lubricating oils samples (SAE-30). Homogeneity, thermal stability and dispersancy of the solutions were determined. Fully soluble oil compounds that are thermally stable up to 250 °C were achieved. The oxidation stability of lube oil samples in the presence of four designed PIBSA additives (varying in the number of amine groups) was determined for a time period of up to 72 hours. The dependence of the additive efficiency on its concentration was studied to achieve maximum stability. Some PIBSA additives at concentration 3.0 · 10⁴ ppm exhibit the best results. Dispersivity values were measured at predetermined oxidation times. The results proved reliable dispersion capability as the nitrogen content of the additive is increased, i.e. the increase in the basic character of the additive leads to the increase in the neutralization capability. Moreover, the designed PIBSA additives retain their efficiency after long oxidation times, confirming their role as multifunctional nitrogen containing polymeric additive. Electronic Publication     

The significance of fullerene electron acceptors in organic solar cell photo-oxidation

Stability of organic solar cells requires development before their commercialisation is possible. This review will give a brief overview of organic solar cells and their stability, before focussing on the photochemical stability of the active layer. The photo-oxidation of the donor polymers will be looked at first which has been studied quite extensively and then fullerene electron acceptors, such as widely used phenyl-C61-butyric acid methyl ester, which has been considerably less studied. It has been shown that oxidation of the fullerene cage on phenyl-C61-butyric acid methyl ester results in oxides with a deeper lowest unoccupied molecular orbital (LUMO) level than the fresh electron acceptor. These oxides act as electron traps, leading to deterioration of the blend photoconductivity. The significance of fullerene photo-oxidation on device stability has been indirectly shown via research on: photoconductivity; organic solar cells made with an oxidised fullerene derivative and organic field effect transistors. Techniques that could be developed to increase photochemical stability of fullerene electron acceptor resistance to photo-oxidation include: reducing its LUMO level; increasing its crystallinity or aggregation and changing its chemical structure. Improving the photochemical stability of organic solar cells would move us one step closer to a more accessible solar power.     

Influence of C60 and Fullerene Soot on the Oxidation Resistance of Vegetable Oils

The influence of fullerene soot as well as pure C₆₀ on the oxidation stability of rapeseed oil is studied. Fullerene soot (C₆₀ content between 0-6 wt.%) was synthesized by using a carbon arc method. Differential scanning calorimetry was applied to estimate the oxidation induction time of fullerene-oil composites. The addition of fullerene soot significantly hampered the peroxide formation thus increasing of oxidation stability of tested oils.     

自然制冷剂R290与冷冻机油的相溶性研究

为了探讨制冷剂R290与冷冻机油的相溶性,建立了一套油与制冷剂相溶性测试实验台,考察了制冷剂R290与矿物油、POE油、PAG油、AB油五种类型冷冻机油的相溶性。结果表明,制冷剂R290在五种冷冻机油中的溶解质量百分含量顺序为：AB油＞环烷基矿物油＞烷基矿物油＞POE油＞PAG油;R290在烷基矿物油、POE油、PAG油中的溶解质量百分含量均随温度的增大而降低,随压力的增大而升高;在环烷基矿物油、POE油、PAG油中的溶解质量百分含量均随运动粘度增大而降低;与运动粘度相比,温度和压力对R290在冷冻机油中的溶解质量百分含量影响较大。     

Catalytic oxidation of benzene using DBD corona discharges

Plasma oxidation of benzene (C(6)H(6)) in oxygen and nitrogen was investigated using a dielectric barrier discharge (DBD) reactor with or without MnO2 or TiO2 at atmospheric pressure and without external heating except plasma heating. An alternative current power supply was used to generate corona discharges for the plasma oxidation. The energy density was controlled under 200 J/L to keep an increase in gas temperature less than 167 K. C(6)H(6) was oxidized to carbon monoxide (CO) and dioxide (CO(2)). Typically, the energy efficiency at an energy density of 92J/L was about 0.052, 0.039, and 0.024 mol/kWh with MnO2, TiO2, and without MnO2 and TiO2, respectively. Benzene oxidation mechanism was mentioned. A comparison on energy efficiency as a function of initial concentration of hydrocarbons, inorganic sulphur compounds, and chloro (fluoro and bromo) carbons was given.     

Characterization and differentiation of gel-like elastomers and compact silicones in order to realize a sensorial rating

Sensorial tests on silicones tackiness perception with naïve consumers show that the stickiness sensation can be disturbed by the sensation of finger penetration into the sample. Indeed a frequent report is that a non-expert people cannot perceive whether tackiness sensation is related to the material adhesion properties or whether it is related to the finger penetration. The samples are both elastomers silicones but some are gel-like elastomers and others are compact silicones. We use an experimental device to realize indentation tests in order to try to differentiate mechanically the two silicones. The apparatus developed in the laboratory allows to characterize and to study the adhesion properties of materials. The analysis of the results should allow to investigate which parameter can influence the sensorial analysis of tackiness.     

Stability of penethamate,a benzylpenicillin ester prodrug,in oily vehicles

Penethamate (PNT) is an ester prodrug of benzylpenicillin which is marketed as dry powder for reconstitution with aqueous vehicle prior to injection. The purpose of this paper was to investigate the chemical stability of PNT in oily formulations to provide a basis for a ready-to-use (RTU) oil-based PNT formulation. The chemical stability of PNT solutions and suspensions in light liquid paraffin (LP), medium chain triglyceride (MIG), ethyl oleate (EO) and sunflower oil (SO) was investigated at 30?°C. Solid state stability of PNT powder and stability of PNT in EO suspensions with different moisture contents were also evaluated. The solubility of PNT in the oils was in order SO?>?EO?>?MIG?>?LP. Degradation of PNT was rapid in oily solutions and less than 10% remained after 7–15 days. Stability of PNT decreased with increase in moisture content in ethyl oleate suspensions. PNT was stable over four weeks in the solid state. Hydrolysis, due to moisture in the oil formulation is not the only degradation mechanism. PNT stability (% drug remaining) in oily suspensions after 3.5 months was in the order LP (96.2%)?>?MIG (95.4%)?>?EO (94.1%)?>?SO (86%). A shelf-life of up to 5.5 years at 30?°C may be achieved for PNT suspension in these oils.     

魔芋葡甘聚糖基缓释膜材料的结构表征

以魔芋葡甘聚糖和大豆油为原料通过碱催化制备魔芋葡甘聚糖脂肪酸酯疏水膜(F-KGM);采用紫外-可见分光光度计、傅立叶变换红外光谱仪、十八角静态激光光散射仪、X射线衍射仪、热分析仪和扫描电子显微镜对其进行结构表征。结果表明,F-KGM的重均分子量(-Mw)为3.653×106g/mol,明显高于KGM的1.619×106g/mol,魔芋葡苷聚糖与脂肪酸分子形成酯键,KGM经酯化后,改变了原有的晶体结构,结晶度降低,具有更高的热稳定性,分子乳化融合流延成膜过程中发生分子自组装行为,形成性质稳定且具有良好疏水性能的缓释膜材料。     

Chemical interactions between an active pharmaceutical ingredient and its counterion in a tromethamine salt under forced degradation conditions

In this study, the tromethamine salt of an active pharmaceutical ingredient containing both a carboxylic acid and ethyl ester functionality was subjected to forced degradation conditions. Based on HPLC-MS analysis, it was found that tromethamine formed both amide and ester type condensation products with the API, with amide formation predominating over ester formation. Addition of tromethamine at the carboxylic acid group of the API was favored over addition at the ethyl ester group. Tromethamine condensation products were observed only under the harshest stress conditions (80 degrees and 75% relative humidity), in which the salt physically changed from a crystalline form to a deliquesced state. Under stress conditions in which the crystalline structure of the salt remained intact, good stability was observed. Thus, the interaction between tromethamine and API occurred only in cases where the crystallinity of the salt was compromised.     

Electrochemiluminescence determination of 2',6'-difluorophenyl 10-methylacridan-9-carboxylate

Electrochemical oxidation of the acridan 2',6'-difluorophenyl 10-methylacridan-9-carboxylate produces the corresponding acridinium ester, which reacts with hydrogen peroxide forming a dioxetanone intermediate. Decomposition of the dioxetanone generates light at 430 nm when it relaxes to the ground state. The effect of pH and hydrogen peroxide concentration on this ECL reaction and on the stability of the acridan were investigated. At pH 8.0 and a hydrogen peroxide concentration of 10 mM, light emission from the ECL reaction was used to determine the acridan concentration with a detection limit of 54 pmol L(-1). Results suggest that acridan esters could be used as labels in ECL immunoassays and nucleotide assays.