制备纳米BaSO4的W/O微乳液体系组成及稳定性

以Triton X-100/正己醇/环己烷/水制成W/O微乳反胶团体系，通过测定体系的电导率和观察液晶相的出现确定相点绘制了各体系的拟三元相图，研究了温度、盐浓度和油相组分对W/O微乳液体系稳定性的影响.实验发现助表面活性剂与表面活性剂的配比对微乳液的稳定性有显著影响.随着温度的升高，W/O微乳液稳定区域减小，可通过升高温度对微乳液进行破乳；与以纯环己烷为油相的体系相比，油相中含有少量正己烷的体系具有更优异的性质.所得结果为利用该W/O微乳液体系制备纳米颗粒提供了基础数据.     

CTMAB微乳体系的相行为研究

进行了CTMAB/正丁醇/环己烷/水微乳液体系相行为的研究。通过制备微乳液,总体了解W/O型微乳液的相应性质,对制备过程中的反应条件做逐一的比较,包括CTMAB微乳体系当中表面活性剂的选择,助表面活性剂的选择,油相的选择,最终选择出最佳的配比。当CTAB与正丁醇的质量比为1∶1时,体系对水的增溶量最大,并且确定(CTAB+正丁醇)与环己烷的质量比为1.5∶1,制备温度选为20℃、p H值选为8时,CTMAB微乳体系有较好的温度和酸碱度。     

基于相图法的W/O型微乳液体系稳定性分析

以辛基苯基聚氧乙烯醚(TX-10)、十二烷基磺酸钠(SDS)和十六烷基三甲基溴化铵(CTAB)为表面活性剂,以正戊醇、正己醇和正庚醇为助表面活性剂,以正戊烷为油相,制备了油包水型(W/O)微乳液.用相图法分析了微乳液体系的热力学稳定性,计算了水核半径的大小,并考察了影响微乳液W/O区域范围的各种因素.结果表明:这几种微乳液体系在实验条件下能自发形成:微乳液的水核半径处于纳米量级,可作为制备纳米粒子的超微反应器;以TX-10为表面活性剂时,水核可以包容更多的水分子,微乳液的W/O区域较大;而以CTAB为表面活性剂时,由于其极性头之间的空间和静电排斥作用强,微乳液的W/O区域最小;以硝酸镧溶液作为分散相时,微乳液的W/O区域变化较小;随着温度的升高,微乳液的W/O区域显著减小.     

纳米氧化铈的制备及其反相微乳液的稳定条件

探讨了用于制备氧化铈纳米粒子的反相微乳体系组成及稳定性,以溴化十六烷基三甲基铵/正丁醇/环己烷/水构成了用于制备纳米氧化铈的W/O微乳液,通过测定体系的电导率的方法确定相点,绘制了溴化十六烷基三甲基铵和正丁醇-环己烷-水反相微乳区拟三元相图.结果表明,表面活性剂与助表面活性剂质量比,即溴化十六烷基三甲基铵与正丁醇的质量比等于1.6时为制备纳米粒子的最佳值,加入硝酸铈会使微乳液的区域减小,随着温度的升高微乳区域略微减小.按实验确定的条件,制备出纳米氧化铈,XRD分析结果表明,纳米氧化铈粒径为19~22 nm.     

含非离子表面活性剂吐温-80的微乳液结构研究

采用非离子表面活性剂吐温-80,以石油醚为油相,正丁醇为助表面活性剂来制备微乳液。用稀释法测定并计算了Tween-80/石油醚/正丁醇/水体系O/W型微乳的结构参数。测量微乳液体系在15~30℃温度范围内的pH及电导,考察温度对微乳液体系的影响。向微乳液体系中加入PVP,测量体系的电导和接触角,考察水溶性高分子对微乳液体系的影响。结果表明微乳液体系的电导随温度的上升而变大,相同温度时,加入PVP会使体系的电导变大,接触角变小。     

反相微乳液法制备负载型Pt基催化剂及其选择加氢活性

采用反相(W/O)微乳液法制备负载型Pt基催化剂,以间氯硝基苯(m-CNB)选择加氢反应为探针,考察微乳液组成、助表面活性剂和油相种类、还原剂用量及载体种类等制备参数对催化剂活性的影响,并对Pt粒子及催化剂进行TEM表征。结果表明：选择十六烷基三甲基溴化胺(CTAB)/正丁醇/环己烷/H2PtCl6溶液的W/O微乳体系...     

TX-100反相微乳液体系稳定性的研究

以最大增容水量为考察目标,研究了温度、HLB值和助表面活性剂含量对TX-100/正己醇/环己烷反相微乳液体系稳定性的影响,绘制了该反相微乳体系的拟三元相图,并用电导率法讨论了微乳液的微观结构。结果表明,当温度t=25℃,TX-100与正己醇质量比为1.5时,体系具有最大的增容水量;在不同的增容水量时体系存在3种不同的微乳区域,即油包水、水包油和油水双连续区域。     

水基性透明液体剂型的加工、性能和差异(Ⅱ)

4 微乳剂 早在20世纪40年代,Hoar和Schulman等人发现油-水混合物借助表面活性剂可以自发地形成透明的分散体系,由于所形成的液滴粒径非常小,后来将这种体系命名为微乳液.此后证明,它是一个热力学上稳定的、均相的水包油型乳液可溶体系,加工的微乳液剂型即为微乳剂. 微乳液存在3种结构类型,即O/W型、W/O型和双连续相结构(也称为中间相微乳型).这3种类型可以在一定条件下互相转变[10].农药上的微乳剂大都为以水为连续相的O/W型乳液.     

吐温-80/对二甲苯/1,2-丙二醇水溶液拟三元体系相图研究

采用稀释法绘制了吐温-80/对二甲苯/1,2-丙二醇水溶液拟三元体系的25℃相图,利用电导法测定了其中微乳液的微观结构。结果表明：体系中包含单相微乳区、两相分层区、白色乳液区三部分,其中微乳区又分为油包水（W/O）微乳区、双连续区（B.C.）、水包油（O/W）做乳区三部分。另外。考察了醇水溶液中醇的质量分数及温度对撒乳区域范围的影响,发现醇的质量分数越高,微乳区域范围越大;温度越高,O/W微乳区域范阻越小。经稳定性实验表明：O/W微乳液稳定.     

W/O型微乳液稳定性实验及PAM水溶液微胶囊制备

基于电导率的测定得到最大增容水量,探究表面活性剂种类、复配后亲水亲油平衡值(HLB)、用量、温度等因素对油包水(W/O)微乳液体系稳定性的影响。结果表明,以Span 80和Tween 80复配的表面活性剂,在HLB值等于5.5的条件下,W/O型微乳液的稳定性最佳。以此为基础,以甲基丙烯酸甲酯(MMA)和甲基丙烯酸丁酯(BMA)的共聚物为壁材,聚丙烯酰胺(PAM)水溶液为芯材,通过原位聚合法合成了微胶囊,并对其形貌及理化性质进行了表征。     

Soybean oil microemulsions with oleic acid/glycols as cosurfactants

The preparation of biocompatible microemulsions of soybean oil in systems made of anionic surfactant, oleic acid, water, and several glycols was considered. The selected glycols were ether derivatives (methyl, ethyl, dimethyl, and diethyl ether) of ethylene glycol and diethylene glycol. The study was performed using pseudoternary phase diagrams in which the three apexes were occupied by soybean oil, a combination of surfactant/oleic acid, and a combination of water/glycol, respectively. The widest regions of microemulsions were obtained for systems containing methyl ether and especially ethyl ether of both ethylene glycol and diethylene glycol. The two latter compounds allowed the preparation of oil-in-water, bicontinuous, and water-in-oil microemulsions with final surfactant contents of 3–4%.     

Effect of Alkyl Sulfate on the Phase Behavior of Microemulsions Stabilized with Monoacylglycerols

In this study the effect of an anionic surfactant (sodium dodecyl sulfate SDS) and oils (hydrocarbons: C12–C16) on the formation and phase behavior of the systems of oil/monoacylglycerols (MAG):SDS/propylene glycol/water has been investigated. The effects of the surfactant mixture on the phase behavior and the concentration of water or oil in the systems were studied at three temperatures (50, 55, 60 °C). Electrical conductivity measurement, FT-IR spectroscopy and differential scanning calorimetry methods were applied to determine the structure and type of the microemulsions formed. The dimension of microemulsion droplets was characterized by dynamic light scattering. It has been stated that the concentration of SDS has a strong influence on the shape and extent of the microemulsion areas. Addition of an ionic surfactant to the mixture with MAG promotes an increase in the area of microemulsion formation in the phase diagrams, and these areas of the isotropic region change with the temperature. It was shown that the presence in the systems of a surfactant more hydrophilic than MAG caused an increase in water content in the microemulsions. It was found that, depending on temperature and concentration of the surfactant mixture, it was possible to obtain a W/O type microemulsion with a dispersed particles size distribution ranging from 20 to 50 nm and containing about 17–38% water in the system. Among different alkanes (from C12 to C16), hexadecane embedded microemulsions showed a maximum water solubilization capacity.     

Model microemulsions containing vegetable oils part 1: Nonionic surfactant systems

Nonionic microemulsions containing triglycerides and fatty acid esters as lipophilic components have been studied. The phase inversion temperature (PIT) of the systems was determined by a conductometric method. Partial phase diagrams were constructed in the phase inversion temperature range. Water solubilization capacity of the nonionic surfactant systems studied was dependent on surfactant and oil types in analogy to ordinary hydrocarbon systems. The PIT:s increased with increased molecular weight for both esters and triglycerides.     

Tar sand extractions with microemulsions: I-the dissolution of light hydrocarbons by microemulsions using 2-butoxyethanol and diethylmethylamine as cosurfactants

For oil sand extractions with microemulsions it is important to disperse large quantities of light hydrocarbons in an aqueous medium. Fundamental studies on the properties of 2-butoxyethanol (BE) and diethylmethylamine (Et₂McN) in water suggest that these two liquids could be more effective cosurfactants than the usual alcohols used for this purpose. The phase diagrams of microemulsions using BE and Et₂MeN as cosurfactants, combined with typical ionic and non-ionic surfactants and typical aliphatic and aromatic hydrocarbons, were therefore investigated and compared with microemulsions based on n-butanol. Although the phase diagrams depend significantly on the nature of the surfactant and of the oil, the monophasic region generally increases with the cosurfactant in the order n-butanol < Et₂McN < BE. With the active mixture BE-cetyltrimethylammonium bromide, temperature has little effect on the phase diagram and NaCl generally destabilizes the microemulsion.     

应用拟三元体系相图法制备烟嘧磺隆微乳剂

介绍了通过绘制烟嘧磺隆／表面活性剂,正丁醇／水拟三元体系相图,制备烟嘧磺隆水基化微乳剂的方法。从表面活性剂筛选入手,对阴离子、非离子表面活性剂复配,确定了水基化微乳液的配方,研究了水质、热贮、冷贮对制剂稳定性的影响,同时进行了流变性及高效液相测定原药含量等实验,分析原药分解率。该方法获得的烟嘧磺隆水基化微乳剂,具有成本低,质量稳定,使用环保、安全,市场前景看好等特点,社会、经济效益显著。     

The effect of type of self-assembled system and pH on the efficiency of corrosion inhibition of carbon-steel surfaces

In this work, three surfactants were used in the preparation of self-assembled systems to inhibit acidic corrosion on API5LX Gr X52 carbon-steel surfaces: CTAB (a cationic surfactant), SDS (an anionic surfactant), and C₁₂E₉ (a non-ionic surfactant). These surfactants were used in the form of aqueous solutions and in microemulsions. Pseudoternary diagrams were constructed using aqueous phases consisting of 0.5 M NaCl at pH = 2, 4 and 7, butan-1-ol as co-surfactant and kerosene as oil phase. The values of c.m.c., maximum surface excess, minimum surfactant cross-sectional area and free energy of micellization were determined using surface tensiometry. The distinct effects of pH and type of self-assembled system on the efficiency of corrosion inhibition have been elucidated by electrochemical techniques (polarization and Tafel curves). It has been demonstrated that these parameters can significantly affect the results, which depend largely on the mechanism of aggregate adsorption on the metal surface and droplet stability. By establishing the optimal conditions, excellent corrosion efficiencies were found for these systems, even at low surfactant concentrations.     

Preparation of SiO2/epoxy nanocomposite via reverse microemulsion in situ polymerization

Reverse water/oil (w/o) microemulsions composed of epoxy resin (EP) (the oil phase) and nonionic surfactant and ammonia aqueous solutions (the water phase) were used in the synthesis of SiO2/EP nanocomposites. The stability of reverse microemulsion was evaluated by measuring water solubilization of the microemulsion. Effects of surfactant type and content, ammonia concentration and temperature on the water solubilization were systematically investigated. Higher water solubilization capacity was obtained by nonionic surfactant TX‐100 compared with other two surfactants, Span‐80 and Tween‐80. Ammonia concentration of 5 wt% and preparation temperature at 35°C were favorable for forming a stable microemulsion and enabling the subsequent hydrolysis and condensation reaction of inorganic precursor tetraethoxysilane (TEOS). SiO2/ epoxy nanocomposites were prepared via in situ polymerization of TEOS within the nanoscale reverse microemulsion “water pool”. FTIR, SEM, and universal testing machine were used to characterize the structural and mechanical properties of the composite. The results revealed that the optimal mechanical properties were obtained at 3 wt% TEOS content. Compared with neat epoxy resin, the tensile and flexural strength of the composite were 40% and 12% higher, respectively. The formation of the silica structure in the hybrid was investigated with FTIR. The SEM and optical observations showed a ductile fracture morphology and good miscibility between inorganic and organic phases. POLYM. COMPOS., 35:1388–1394, 2014. © 2013 Society of Plastics Engineers     

Olive oil microemulsions as a biomimetic medium for enzymatic studies: Oxidation of oleuropein

Microemulsions consisting of olive oil as the non-polar solvent, lecithin as surfactant, 1-propanol as cosurfactant, and water were prepared. The choice of the compositions of the microemulsions used was based on the pseudo-ternary phase diagrams of the system determined at 30°C, for different weight ratios of lecithin/olive oil. Lecithin solubilization and water incorporation in these microemulsion systems was limited. Tyrosinase, an oxidizing enzyme present in olives, was successfully incorporated in the water core of these microemulsions. Enzymatic oxidation of oleuropein, the most abundant olive phenolic compound, in the restricted aqueous environment of olive oil microemulsions was studied. Formation of oleuropein oxidation products was followed spectrophotometrically at 30°C for several minutes. An absorption maximum was observed at 415 nm. When the enzymatic reaction was considered at different tyrosinase and oleuropein concentrations, a rapid inactivation of the enzyme was observed. Addition of l-proline as a coupling reactor did not succeed in preventing enzyme inactivation in the microemulsions, probably owing to substrate localization and product accumulation around the entrapped enzyme molecules in the micellar interface.