二元乳状液稳定性影响因素的研究

制备了聚合物/表面活性剂二元乳状液,考察了聚合物相对分子质量、聚合物质量浓度、表面活性剂质量分数、油水比(原油与聚合物/表面活性剂二元乳状液体积比)对二元乳状液稳定性的影响。结果表明:提高表面活性剂的质量分数和聚合物的质量浓度,采用相对分子质量较低的聚合物,降低油水比,有利于二元乳状液的稳定。     

以酯基为连接基的非离子双子表面活性剂的合成

以蓖麻油酸（RA）、聚乙二醇（600）为原料,马来酸酐为连接基,合成了一种新型的非离子双子表面活性剂MARAPEG-15,考察了催化剂用量、物料摩尔配比、反应时间及温度对酸酐与蓖麻油酸聚乙二醇硼酸酯酯化的影响,并测定了产物的临界胶束浓度和表面张力。马来酸酐与蓖麻油酸聚乙二醇硼酸酯酯化较佳的工艺条件为：催化剂用量为总质量的3%,n（酸酐）∶n（蓖麻油酸聚乙二醇硼酸酯）为3.1∶2,反应温度为110℃,时间为4 h;硼酸酯键水解时间为1.5 h。产物的表面张力及其临界胶束浓度为γCMC=35.73 mN/m,CMC=1.96×10-5mol/L。     

一步法合成十二烷基葡萄糖苷反应过程研究

以正十二醇和葡萄糖为原料一步法制备十二烷基葡萄糖苷,研究了不同反应条件(催化体系、催化剂用量、温度、醇糖比等)对反应过程转化率和选择性的影响,提出了此反应过程的物理模型。研究结果表明,合成十二烷基葡萄糖苷的反应主要由生成十二烷基葡萄糖苷的主反应和生成多糖的副反应组成。十二醇与葡萄糖反应生成烷基葡萄糖苷的主反应属于液相反应机理,首先葡萄糖溶解于十二醇中,然后与十二醇发生均相反应,碳正离子与十二醇的反应是整个反应的控制步骤。反应过程中,反应体系中部分固相葡萄糖处于熔融状态,能捕捉液相中的催化剂,生成多糖副产物。不同反应条件下的实验结果表明,此反应机理能很好地描述反应过程,为此反应过程的动力学研究提供了理论基础。     

羧酸盐型双子表面活性剂合成研究进展

羧酸盐双子表面活性剂因其具有独特的物理化学性能及易生物降解等特性而广受国内外学者关注。本文主要对羧酸盐双子表面活性剂分子的疏水链、亲水基及联接基团的键合方式进行了概述。     

Amphiphilic Properties of Dodecylammonium Chloride/4-(1-Pentylheptyl) Benzene Sodium Sulfonate Aqueous Mixtures and Study of the Catanionic Complex

Surfactants are often used in supramolecular chemistry, due to their ability to self-organize. Surfactant molecules aggregate spontaneously and reversibly to adopt a defined intermolecular arrangement. In this work, general phase behavior, adsorption and association in aqueous mixtures of dodecylammonium chloride, DACl and sodium 4-(1-pentylheptyl) benzenesulfonate, NaDBS, were studied by a combination of techniques including surface tension and conductivity measurements, light scattering and optical microscopy. The strong synergistic properties of the system were brought out with the Regular Solution Theory. Various colloidal objects are observed in wide range of composition: conventional small vesicles, large giant multilamellar or multivesicular vesicles. An excess of NaDBS provides extremely large tubular and elongated multilamellar vesicles. The new catanionic 1:1 complex, dodecylammonium-4-(1-pentylheptyl) benzenesulfonate, formed in the equimolar conditions is a result of intramolecular charge neutralization. The thermal properties of this solid compound were examined by thermal polarizing microscopy, differential scanning calorimetry, and X-ray diffraction. The most probable ion-pair amphiphilic cluster of the crystal smectic phase, at room temperature, consists of ionic groups formed in ordered layers with dodecyl chains packed into somewhat disordered layers, tilted to the layer plane.     

Preparation and Characterization of C10–C14 Alkyl Cellulose Ester Sulfate Surfactant

The aim of this work is to synthesize surfactants based on cellulose with different molecular weights. Raw cotton cellulose was tailored into cellulose segments with different molecular weights by a hydrothermal process, then the average degree of polymerization (DP) was determined by viscosimetry and the molecular weight distribution was estimated by gel permeation chromatography. The C₁₀–C₁₄ alkyl cellulose ester sulfate surfactants were prepared by hydrophilic sulfonation and hydrophobic esterification. The surface tension of the surfactants solution was obtained by the Wilhelmy plate method. Results showed that the cellulose segments presented a broader distribution compared with the raw material. The critical micelle concentration (CMC) value decreased from 1.08 to 0.86 wt% as the hydrophobic chain length was increased from 10 to 14. The CMC values of cellulose surfactants with C₁₄-acyl chloride hydrophobization decreased from 1.32 to 0.86 wt% as the DP was decreased from 2,700 to 296.     

Synthesis and Surface Properties of Novel Gemini Imidazolium Surfactants

Five new Gemini imidazolium surfactants were synthesized from imidazole and 1-bromoalkane (C₈, C₁₀, C₁₂, C₁₄, C₁₆) to get 1-alkylimidazole, which was further reacted with 1,3-dichloropropan-2-ol to form the surfactant molecule, 1,1′-(propane-1,3-diyl-2-ol) bis(3-alkyl-1H-imidazol-3-ium) chloride. The structures of the five new surfactants and intermediates were characterized by ¹H-NMR, ¹³C-NMR and IR spectra. Thermal properties of the five new surfactants were studied with thermogravimetric analysis and differential scanning calorimetry, the five new surfactants showed a transition from a crystalline phase to a thermotropic liquid–crystalline phase at around ca. 100 °C, which transformed to an isotropic liquid phase at around ca. 165 °C. The five new surfactants critical micelle concentrations (CMC) in the aqueous solutions were determined by surface tension and electrical conductivity methods. The surface tension measurements provided a series of parameters, including critical micelle concentration (CMC), surface tension at the CMC (γ _CMC), adsorption efficiency  (pC ₂₀), and effectiveness of surface tension reduction (π_CMC). In addition, with application of the Gibbs adsorption isotherm, maximum surface excess concentration (Γ_max) and minimum surface area/molecule (A_min) at the air–water interface were obtained. The parameters β (degree of counterion binding to micelles), ΔG _ads ^θ (Gibbs free energy of adsorption), and ΔG _mic ^θ (Gibbs free energy change of micellization) were also derived. The results indicated that the five new Gemini surfactants exhibited very low CMC and a good efficiency in lowering the surface tension of water. The foamability and foam stability of the five new surfactants were also examined at different CMC.     

Effect of Hydrophobicity and Temperature on the Interactions in the Mixed Micelles of Triblock Polymers [(EO76PO29EO76) and (EO19PO69EO19)] with Monomeric and Gemini Surfactants

The interactions in the mixed micelles of two triblock polymers, F68 (EO₇₆PO₂₉EO₇₆) and P123 (EO₁₉PO₆₉EO₁₉), with a series of monomeric (dodecyltrimethyl ammonium bromide, tetradecyltrimethyl ammonium bromide and cetyltrimethyl ammonium bromide) and gemini {dimethylene bis(alkyldimethyl ammonium bromide), m-2-m, where m = 10, 12 and 14} cationic surfactants were studied by surface tension and viscosity measurements in aqueous solutions at different temperatures. The mixed micellar and interfacial properties of the binary mixtures were analyzed using Clint, Rubingh, Rosen and Maeda approaches. Both F68 and P123 show weak interactions with the studied cationic surfactants at 298.15 K which become favorable (synergistic) at higher temperatures. Further, the synergistic interactions are more in mixtures of P123 than F68 at higher temperatures. A comparison of the effects of number of EO and PO blocks in triblock polymers on various physicochemical parameters of the mixed micelles has also been made. The unfavorable enthalpy changes are compensated by favorable entropy changes as a result of the hydrophobic effect. The relative viscosity (η _r) studies show that the size of the micelles formed by pure P123 is smaller than those of F68. The values of η _r for the mixed micelles of F68 show significant variation with chain length of gemini surfactants whereas no such effect is seen in mixtures with P123.     

非离子表面活性剂作用下分散染料对棉沾色机理研究

通过研究非离子表面活性剂结构和浓度对C.I.分散红60增溶量、分散体系的高温稳定性、C.I.分散红60的上染率以及染浴中染料残留量的影响,探讨了在非离子表面活性剂作用下C.I.分散红60对棉沾色的机理。结果表明:非离子表面活性剂用量较低(0.5 g/L左右)时,分散体系有较好的高温稳定性,此时非离子表面活性剂对分散染料的增溶量为影响沾色的主要因素,分散染料的增溶有利于减少其对棉的沾色;随着非离子表面活性剂用量的增加(≥1 g/L),染料的上染百分率和分散体系的高温稳定性降低,分散染料对棉的沾色加重,沾色等级降低到2级。