多重乳状液稳定性的研究

多重乳状液稳定性的研究刘沛妍，褚莹，吴子生，严忠，康万利（东北师范大学化学系，长春，１３００２４）（大庆石油学院，安达）关键词多重乳状液，示踪法，稳定性Ｗ／Ｏ型或Ｏ／Ｗ乳状液的稳定性是研究得比较成熟的课题［１］，但对Ｗ／Ｏ／Ｗ型多重（层）乳状液稳定性...     

烯丙基硅烷的一步法合成研究

采用一步合成方式,将3-溴丙烯与金属镁在以甲苯和供电子溶剂(乙醚或THF)构成的混合溶剂中进行反应,继而与四氯化硅反应,成功合成了四烯丙基硅烷,其产率在乙醚与3-溴丙烯的摩尔比为4(V甲苯/V乙醚=1·1)时达到极值,超过了91%。研究同时发现,选择THF代替乙醚时,同样在THF与3-溴丙烯的摩尔比为4(V甲苯/VTHF=1·7)时产率达到极值(63·12%)。本过程可提高产率,降低成本,是一条好的生产四烯丙基硅烷的路线。     

CdS量子点的一步法合成及量子产率

以油酸为配体,十八烯为溶剂,采用一步法合成了CdS量子点,研究了反应温度、反应时间和Cd/S的摩尔比对量子点光谱性能的影响.X射线衍射(XRD)和高分辨透射电镜(HRTEM)测试结果表明,所获得的CdS量子点为立方闪锌矿结构,且尺寸分布均一,结晶度高,其较强的带边发光、尖锐的紫外吸收峰以及狭窄的荧光发射峰进一步表明量子...     

水热体系合成锂皂石结构的演化和影响规律研究

以氟化锂、氯化镁、水玻璃、氨水为主要原料，采用水热体系合成了锂皂石（Hectorite）。通过化学成分分析、粉末X-射线衍射（XRD）、场发射扫描电镜（SEM）、 傅立叶变换红外光谱（FTIR）、 热重和差示扫描量热（TG-DSC）、激光纳米粒度分析等技术，考察了晶化时间、原料比、晶化温度对锂皂石产物结构演化的影响规律。实验结果表明，采用水热晶化体系合成锂皂石，6 h后体系中即能生成锂皂石。在实验的6～49 h晶化时间范围内，体系为锂皂石、硅酸锂、氟化锂、氢氧化镁等组成的多相共存体系。经72 h晶化后生成结晶好的锂皂石。在水热晶化体系增加锂盐的量，有利于提高锂皂石结晶性，并能促进Li取代片层上六配位Mg，导致产生更高的层电荷和更多的层间可交换离子。提高水热晶化温度，对提高锂皂石产物结晶性有利。晶化时间短，锂皂石产物粒径小，结晶性差，但颗粒分布窄。晶化时间长，锂皂石产物粒径增大，结晶性好，热稳定性提高。     

白油乳状液稳定性实验研究与机理分析

乳状液的微观特征影响着油包水乳状液的稳定性,从而影响油基钻井液的稳定性能。室内选用3^#白油、26%CaCl₂水溶液、JH主辅乳化剂,采用超声分散乳化方法,配制得到油包水型白油乳状液。采用显微图像技术,研究了JH主辅乳化剂加量、油水比、有机土对白油乳状液微观特性的影响;以油水界面张力、动态界面张力以及界面扩张粘弹性等为参数分析了乳状液稳定性的机理。结果表明：JH主辅乳化剂配比为4∶1,加量为4%,油水比为80∶20时,白油乳状液中的分散相呈球形液珠,直径为3.31～12.93μm;油水界面张力为0.559 mN·m^-1;JH主辅乳化剂形成的油水界面膜强度大,白油乳状液稳定性好;有机土与JH主辅乳化剂的协同作用使白油乳状液和油基钻井液的稳定性能显著提高。     

一步法合成二甲醚整体式催化剂的制备及反应性能研究

以蜂窝陶瓷为载体、γ-Al₂O₃为惰性涂层、C301/HZSM-5为活性组分制备出一种整体式合成二甲醚催化剂。BET、XRD和SEM分析结果表明,活性组分均匀负载在载体表面上,催化剂具有良好的结构和织构特点。在固定床反应器中考察了整体式催化剂上CO加氢一步法合成二甲醚的反应性能,并与C301/HZSM-5颗粒（粉末）催化剂进行了比较。在温度260℃、压力4.0MPa、合成气空速1500mL/(g·h)的条件下,整体式催化剂上CO转化率达到79.62%,二甲醚选择性为70.58%,分别比C301/HZSM-5颗粒催化剂高出7.78%和9.44%。100h的稳定性实验结果表明,整体式催化剂可以保持较高的活性和选择性,而颗粒状催化剂的活性有明显的下降。
     

含TOMAC乳状液膜萃取L-苯丙氨酸的迁移机理及应用

以L 苯丙氨酸在液膜体系里的迁移机理为基础 ,把液膜萃取过程中的萃取和反萃两个连续过程结合起来加以研究 ,推出了在整个液膜体系达到萃取终了时的内外相氨基酸浓度比公式 ,并以TOMAC为载体萃取L 苯丙氨酸为例 ,讨论了影响液膜萃取的控制因素 ,实现了L 苯丙氨酸的有效回收。     

乳状液膜法迁移及分离钯(Ⅱ)的研究

本文采用以叔胺N_{7301为流动载体、span 80为表面活性剂、煤油为膜溶剂、EDTA作内相试剂的乳状液膜体系迁移分离钯(Ⅱ)。确证了其迁移机理。实验表明在所筛选出的适宜制乳及迁移分离等最佳条件下，96%以上的Pd(Ⅱ)迁入内相，并能有效地与Cu²⁺、 Zn²⁺、Cd²⁺、Pb²⁺、Ni²⁺、Fe²⁺等离子分离。}     

Brij类表面活性剂与Laponite纳米颗粒的相互作用及其稳定乳液的研究

通过表面张力、Zeta电位和流变学参数的测定, 研究了聚氧乙烯烷基醚类非离子型表面活性剂(Brij 30和Brij 35)在合成锂皂石(Laponite)纳米颗粒表面的吸附及对Laponite水分散体系中颗粒间相互作用和体系粘度的影响. 结果表明, 这类表面活性剂能显著地吸附在Laponite颗粒表面上, 且吸附量随其分子中POE链长短而不同. 这种吸附没有改变Laponite粒子的带电性质, 但一定程度地降低了Laponite颗粒Zeta电位; 吸附也会减弱颗粒间的相互作用, 降低体系的粘度. 实验以Laponite和Brij为乳化剂, 制备了O/W型乳状液. 乳液稳定性变化和乳液粒径分布结果表明, 体系中Brij的浓度较低时, 乳液的性质主要是由Laponite颗粒决定的; 而Brij浓度较高时, 则主要取决于Brij表面活性剂. 高速剪切含Brij的Laponite水分散体系, 剪切后表面张力随时间的变化表明, 剪切作用会使得吸附在Laponite颗粒表面的Brij分子不同程度地解吸下来. 这也意味着乳液制备时, 高速剪切作用也会造成Brij分子自Laponite颗粒表面的脱附, 这可能是非离子表面活性剂与阳离子表面活性剂对负电固体颗粒稳定乳液影响不同的原因.     

一步法合成沙利度胺及其重要的衍生物

沙利度胺（1）最早是由德国的一家制药公司在20世纪50年代上市的一种用于镇静和孕妇止吐的药物,当时被认为是一个毒性很小的药物,但是很快就发现这个药物有非常强的致畸性,于是在1962年这个药物撤出了市场。后期研究结果表明,沙利度胺的致畸性是由其5－异构体导致的,     

Surfactant-Free Multiple Pickering Emulsions Stabilized by Combining Hydrophobic and Hydrophilic Nanoparticles

A series of W/O/W or O/W/O emulsion stabilized solely by two different types of solid nanoparticles were prepared by a two-step method. We explored the option of particular emulsifiers for the multiple Pickering emulsions, and a variety of nanoparticles (silica, iron oxide, and clay) only differing in their wettability was used. The primary W/O emulsion was obtained by the hydrophobic nanoparticles, and then the hydrophilic nanoparticles were used as emulsifier in the secondary emulsification to prepare the W/O/W emulsion. In a similar way, the primary O/W emulsion of the O/W/O emulsion was stabilized by the hydrophilic nanoparticles, while the secondary emulsification to prepare the O/W/O emulsion was effected with the hydrophobic nanoparticles. The resultant multiple Pickering emulsion was stable to coalescence for more than 3 months, except the W/O/W emulsions of which the secondary emulsion stabilized by clay nanoparticles became a simple O/W emulsion in a day after preparation. Moreover, the temperature and pH sensitive poly(N-isopropylacrylamide-co-methacrylic acid) (P(NIPAm-co-MAA)) microgels were introduced as an emulsifier for the secondary emulsification to obtain the stimulus-responsive multiple W/O/W emulsion. Such microgel-stabilized multiple emulsions could realize the efficient controlled release of water-soluble dye, Rhodamine B (RB) on demand in a multiple-emulsion delivery system.      

Chemical One Step Method to Prepare Polyaniline Nanofibers with Electromagnetic Function

A “Chemical one step method” (COSM) is proposed to prepare electromagnetic functional composite nanofibers of polyaniline (PANI/γ‐Fe₂O₃) having a diameter of ≈20 nm. In this approach FeCl₃ is acts as the oxidant either for polymerization of aniline or for preparation of γ‐Fe₂O₃ magnets. Besides, it also provides protons produced by the hydrolysis process for doping PANI. It is found that the composite nanofibers have a high conductivity (10⁻¹ ∼ 10⁰ S · cm⁻¹) and super‐paramagnetic properties (M_s = 0.46 ∼ 6.03 emu · g⁻¹ and H_c = 0) at room temperature, where the conductivity is mainly affected by the molar ratio of FeCl₃ to aniline monomer whereas the magnetic properties are dominated by the amount of FeCl₂.

     

室温一步固相反应合成纳米氧化锌的表征、光催化性能及动力学

以七水硫酸锌、氢氧化钠为原料,采用室温一步固相反应合成ZnO纳米粒子,并分别利用X射线衍射分析（XRD）、傅里叶变换红外光谱分析（FTIR）、热重分析（TG）、扫描电子显微分析（SEM）、透射电子显微分析（TEM）、N₂吸附-脱附、紫外可见漫反射光谱分析（UV-Vis DRS）等方法对ZnO纳米粒子进行表征。实验结果表明：不需任何添加剂,室温下可通过一步固相反应合成ZnO纳米粒子,其形成过程首先是ZnSO₄·7H₂O和NaOH充分接触,然后反应形成Zn₄SO₄（OH）₆·5H₂O,最后NaOH的溶解热可使Zn₄SO₄（OH）₆·5H₂O转变为ZnO并逐渐长大形成纳米粒子。同时以甲基橙为降解对象评价了ZnO纳米粒子的光催化活性,实验结果表明：紫外光照射下,该方法合成的ZnO纳米粒子对甲基橙具有较好的光催化活性,且光催化动力学方程符合准一级反应动力学。     

Tailoring of High‐Order Multiple Emulsions by the Liquid–Liquid Phase Separation of Ternary Mixtures

Multiple emulsions with an “onion” topology are useful vehicles for drug delivery, biochemical assays, and templating materials. They can be assembled by ternary liquid phase separation by microfluidics, but the control over their design is limited because the mechanism for their creation is unknown. Herein we show that phase separation occurs through self‐similar cycles of mass transfer, spinodal decomposition or nucleation, and coalescence into multiple layers. Mapping out the phase diagram shows a linear relationship between the diameters of concentric layers, the slope of which depends on the initial ternary composition and the molecular weight of the surfactant. These general rules quantitatively predict the number of droplet layers (multiplicity), which we used to devise self‐assembly routes for polymer capsules and liposomes. Moreover, we extended the technique to the assembly of lipid‐stabilized droplets with ordered internal structures.     

Formula Optimization of Emulsifiers for Preparation of Multiple Emulsions Based on Artificial Neural Networks

Formulation optimization of emulsifiers for preparing multiple emulsions was performed in respect of stability by using artificial neural network (ANN) technique. Stability of multiple emulsions was expressed by the percentage of reserved emulsion volume of freshly prepared sample after centrifugation. Individual properties of multiple emulsions such as droplet size, δ, viscosity of the primary and the multiple emulsions were also considered. A back‐propagation (BP) network was well trained with experimental data pairs and then used as an interpolating function to estimate the stability of emulsions of different formulations. It is found that using mixtures of Span 80 and Tween 80 with different mass ratio as both lipophilic and hydrophilic emulsifiers, multiple W/O/W emulsions can be prepared and the stability is sensitive to the mixed HLB numbers and concentration of the emulsifiers. By feeding ANN with 39 pairs of experimental data, the ANN is well trained and can predict the influences of several formulation variables to the immediate emulsions stability. The validation examination indicated that the immediate stability of the emulsions predicted by the ANN is in good agreement with measured values. ANN therefore could be a powerful tool for rapid screening emulsifier formulation. However, the long‐term stability of the emulsions is not good, possibly due to the variation of the HLB number of the mixed monolayers by diffusion of emulsifier molecules, but can be greatly improved by using a polymer surfactant Arlacel P135 to replace the lipophilic emulsifier.     

Synthesis and Characterization of Nano-silica/Polyacrylate Composite Emulsions by Sol-gel Method and in-situ Emulsion Polymerization

Organic nano-silica was firstly synthesized by sol-gel method with methyl methacrylate (MMA) and butyl acrylate (BA) in the micelles as dispersing media, tetraethoxysilicate (TEOS) as precursor, hydrochloric acid as catalyst and methacryloylpropyl trimethoxysilane (A174) as modifier. Subsequently, the nano-silica/polyacrylate composite emulsions were directly prepared by in-situ emulsion polymerization under the action of the initiator. The structure and properties were characterized by Fourier transform infrared spectroscopy (FTIR), dynamic light-scattering (DSL), thermogracvimetry (TG) and transmission electron microscopy (TEM). The results showed that A174-modified nano-silica was successfully synthesized in the acrylate-based emulsions by the sol-gel method. The nano-silica was encapsulated by polyacrylate, and the composite latex particles exhibited an apparent core-shell structure. The A174 could improve the lipophilicity of nano-silica and increase the grafting efficiency of polyacrylate on nano-silica particles. The nano-silica/polyacrylate composite latex film had better thermal stability, and the composite latex particles had greater average size and broader size distribution in contrast to those of pure polyacrylate emulsions.     

Osmotically Driven Formation of Double Emulsions Stabilized by Amphiphilic Block Copolymers

Double emulsions are valuable for the formation of multi‐compartmental structures. A variety of pathways to prepare double emulsions have been developed, but high‐throughput routes to droplets of controlled size and architecture remain scarce. A new single‐step process is introduced for preparation of water‐in‐oil‐in‐water double emulsions by a previously unexplained process of self‐emulsification. We show that the origin of this process is the osmotic stress resulting from the presence of salt impurities within the amphiphilic block copolymers used for emulsion stabilization. Further, we utilize osmotically driven emulsification to tailor the structures of multiple emulsions, which upon solvent evaporation can yield multi‐compartmental capsules or hierarchically structured porous films.     

硅氧烷乳液聚合过程中大颗粒形成机理研究Ⅰ．阳离子型乳液的耐电解质稳定性

探讨了二甲基聚硅氧烷阳离子型乳液耐电解质稳定性的影响因素。结果表明,加入少量的非离子型表面活性剂与阳离子型乳化剂并用进行乳液聚合,可以保护乳液粒子,防止由于电解质引起的乳液粒子的相互凝聚而形成大颗粒。     

硅氧烷乳液聚合过程中大颗粒形成机理研究：Ⅰ.阳离子型乳液的耐电解质…

探讨了二甲基聚硅氧烷阳离子型乳液耐电解质稳定性的影响因素。结果表明，加入少量的非离子型表面活性剂与阳离子型乳化剂并用进行乳液聚合，可以保护乳液粒子，防止由于电解质引的乳液粒子的相互凝聚而形成大颗粒。