Polyperoxide surfactants for interface modification and compatibilization of polymer colloidal systems. I. Synthesis and properties of polyperoxide surfactants

Anhydride‐containing polyperoxides were synthesized by copolymerization of 5−tert−butylperoxy−5−methyl−1−hexen−3−yne with either maleic anhydride or its blends with styrene. The integral composition of the polyperoxides was theoretically calculated as the copolymerization process proceeded and its direct experimental evidence was obtained. In macrochain‐formation behavior, the process was found to be consistent with the generally accepted regularities of binary and ternary copolymerization. By employing their polymerizational transformations, water‐soluble polyperoxides exhibiting surface activity and initiating properties were obtained. In aqueous solutions, such polyperoxide surfactants form micellelike colloidal structures. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 1217–1227, 2000     

Effect of cefoperazone sodium on the physicochemical properties of surfactants

The effects of cefoperazone sodium (CS), a pharmaceutical compound, on the critical micelle concentration (CMC) of surfactants with different charges [cetyl trimethylammonium bromide (CTAB), sodium dodecyl sulfate (SDS), and Triton X-100], the cloud point of Triton X-100, and the Krafft temperatures of SDS and CTAB were studied. The interaction of CS with differently charged surfactants was determined by ultraviolet and fluorescence spectrophotometry. The results show that with increasing CS concentration, the Krafft temperature increases and the CMC decreases in the SDS/H₂O system, whereas the opposite results are obtained in the CTAB/H₂O system. Both the cloud point and the CMC of Triton X-100 increase with the addition of CS. The above results are attributed to the different micellar interactions between CS and surfactants with different charges.     

新型双子两性表面活性剂的合成及性能

以十二烷基叔胺、环氧氯丙烷和氧氯化磷为原料合成了一种新型双子两性磷酸酯表面活性剂。在三亚甲基中引入PO43-作为柔性基团来提高联接基团的亲水性。通过红外光谱对合成的表面活性剂进行了结构表征。测试了该表面活性剂的水溶液最低表面张力为31.9 mN/m、临界胶束浓度为1.4×10-4mol/L、等电点为pH 8.5~10.5,c20=1.41×10-5mol/L。考察了其发泡性、乳化性等,通过摄像显微镜对乳化效果进行了观察。     

Phase behavior of laundry surfactants in polar solvents

Laundry surfactants are usually mixtures of ionic and nonionic detergents that exhibit a complex phase behavior. Here the ternary phase behavior of an isotropic and a liquid crystalline (LC) surfactant mixture has been examined in water/solvent systems. The size of the LC area in the ternary phase diagram was correlated to solvent parameters including the dielectric constant and the Gordon cohesiveness parameter. The Gordon parameter was found to have a linear relationship with the amount of solvent needed to go from an LC to an isotropic state over a wide range of solvents from polar to apolar. For solvents in which no surfactant aggregation (micellar or inverted micellar) is expected, the size of the LC area is linear with the reciprocal of the dielectric constant of the solvent. On diluting practical detergent liquids with water, a large LC area can be avoided by using solvents with a relatively low dielectric constant and with a relatively low molecular weight. The aggregated state of the surfactant mixtures in the isotropic regions of the phase diagram was studied using the solvatochromic fluorescent probe Nile Red. In the water corner of the phase diagram, the surfactants are aggregated into micelles. In strongly polar solvents, such as glycerol, ethylene glycol, formamide, and ethanolamine, the surfactants are also aggregated into micelles. In somewhat less polar solvents, such as methanol, ethanol, and t-butanol, the surfactant molecules are randomly distributed. In the surfactant-rich corner of the phase diagram of the isotropic mixture, the surfactant forms inverted micelles. An inverted micelle-to-micelle transition could be observed on dilution in ethylene glycol as a discontinuity in the trend of the Nile Red fluorescence maxima.     

Effect of various parameters on sodium dodecyl sulfate (SDS) flux through a collagen membrane

The influence of various experimental parameters on the flux of sodium dodecyl sulfate (SDS) through a collagen membrane has been studied. The variables evaluated were donor concentration, time, temperature, pH and ionic strength. Data on the influence of both surfactant concentration and time on surfactant diffusion through the collagen film allow one to postulate a diffusion process mainly of the monomeric type. This diffusion mechanism based on surfactant monomers has been corroborated by studying the effect of ionic strength. Thisin vitro technique could be a useful tool to predict the effect of diverse experimental parameters on the percutaneous absorption of surfactants.     

氨基酸表面活性剂体系的增稠研究

研究了氨基酸表面活性剂的增稠方法,通过椰油酰胺丙基甜菜碱和甘油月桂酸酯对椰油酰谷氨酸钠、月桂酰肌氨酸钠、椰油酰丙氨酸钠进行增稠。调节pH(5.1~5.5),椰油酰谷氨酸钠体系黏度随pH降低逐渐增大,pH为5.4时椰油酰丙氨酸钠体系黏度最大,pH为5.3时月桂酰肌氨酸体系黏度最大。在椰油酰丙氨酸钠体系中,研究了H~+浓度、椰油酰胺丙基甜菜碱和甘油月桂酸酯的协同增稠作用,且增加甘油月桂酸酯用量,体系可获得更高黏度,所需H~+也更少。皱波角叉菜对氨基酸表面活性剂的增稠与其加入量相关,随着皱波角叉菜添加量的增加,体系黏度逐渐增大。     

Mixing from Fickian diffusion and natural convection in binary non‐equilibrium fluid phases

A two‐dimensional (2‐D) model that describes mass transport between non equilibrium gas and liquid phases of a binary non polar mixture in a closed system of fixed volume and temperature is presented. Diffusion, convective mass transport due to compressibility and non ideality, and the motion of the interface upon evaporation and dissolution are accounted. Natural convection in both phases is incorporated, which allows to study the effect of density increase in the liquid phase from gas dissolution. The Peng‐Robinson equation of state is used to calculate the densities and the fugacities needed to find the interfacial composition consistent with local chemical equilibrium. The results obtained with a one‐dimensional model was compared to our 2‐D results, showing that natural convection influences the mixing time drastically. In the liquid bulk phase, convective flux is much higher than diffusive flux. Across the interface, diffusive flux is, however, the dominating flux, which allows accurate measurement of diffusion coefficients at high pressure in 2‐D domains. © 2011 American Institute of Chemical Engineers AIChE J, 2012     

Kinetics of precipitation of surfactants. II. Anionic surfactant mixtures

Precipitation kinetics were measured for calcium-induced precipitation of mixtures of two anionic surfactants. The overall time required for precipitation to occur increased dramatically in specific ranges of compositions for the surfactant mixtures when compared to single components. Adsorption of the nonprecipitating surfactant onto the precipitate surface was shown to be responsible for this remarkable synergism. The higher the supersaturation of surfactant monomers, the more rapidly precipitation occurred. Under conditions where both surfactants were supersaturated, precipitation sometimes occurred in stepwise fashion, where crystals of different composition were formed with different induction times. Image analysis of the crystalline precipitate showed that crystal habit was affected when the two surfactants were mixed, indicating that processes such as adsorption and coprecipitation (most likely by inclusion) were occurring. When the crystals were allowed to age in solution for a period of 1 wk, the crystalline phase from the mixed surfactant solutions was found to separate into two types of crystals, which resembled week-old crystals formed from single surfactant systems.     

V-L-S multiphase equilibrium in bitumen-diluent systems

A multiphase flash algorithm is developed for the prediction of V-L-L-S equilibrium. The algorithm uses the Patel-Teja equation of state for the fluid phases and a separate model, based on vapour pressure, for the solid phase. A novel technique is presented for avoiding the phase disappearance problem commonly encountered in multiphase equilibrium calculations involving multiple fugacity models. The predictions are shown to be in good agreement with the data for several CO₂ and hydrocarbons V-L-S systems. This paper also presents new experimental data for the solubility of Peace River bitumen in n-pentane, n-heptane and n-octane at atmospheric conditions, and these are compared with the model predictions.     

Synthesis of new extended surfactants containing a carboxylate or sulfate polar group

New extended anionic surfactants with a carboxylate or sulfate polar head were synthesized from polypropoxylated alcohols, and their structures were confirmed by ¹H and ¹³C nuclear magnetic resonance analysis. The extended surfactant critical micelle concentration was found to decrease with the length of the polypropylene glycol spacer. Surfactants containing a diethylene glycol link to the head group exhibited a higher critical micelle concentration than did their nondiethoxylated homologs.     

Effects of sulfonated surfactants on parallel diffusion of mono azo dye with high aggregation constant into cellulose membranes

The effects of sulfonated surfactants on the adsorption and diffusion of mono azo dye into water‐swollen cellulose membranes were studied at 25–55°C. The results were analyzed on the basis of the parallel diffusion theory of surface and pore diffusion. Addition of the surfactants increased the equilibrium adsorption of the dye onto cellulose and the pore diffusivity for the parallel diffusion model. The surface diffusivity for the model was not affected. The temperature dependence of the effects was also discussed. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 1781–1785, 2002     

马来酸酐双酯型表面活性单体的合成和性质

表面性单体（也称为可聚合表面活性剂），既具有表面活性又可以与聚合单体发生聚合反应，可以改善聚合物乳液的稳定性，提高乳液成膜后的耐水性，其中以马来酸酐为反应基团的表面活性单体，由于其不易发生均聚反应而具有特殊的意义，首先以马来酸酐和十二醇为原料制备马来酸酐单十二醇酯，然后与环氧丙基三甲基氯化胺反应合成了3种新型的马来酸酐双酯型阳离子表面活性单体，产品的结构用红外光谱，核磁共振氢谱以及元素分析进行了表征，该产品能显著降低水的表面张力（22mN.m^-1,26mN.m^-1)，并具有较低的临界胶束浓度（0.2mmol.L^-1-0.6mmol.L^-1)。     

Comments on modelling the diffusion-controlled adsorption of surfactants

In this study, dynamic interfacial tension data are obtained with a drop volume tensiometer at the mineral oil-water interface for Triton X-100 dissolved in the water phase, and for Span 80 dissolved in the oil phase. Surfactant adsorption is modelled under diffusion-controlled conditions using either long or short diffusion time approximations. A dimensionless parameter relating adsorption time, t_a, to a characteristic diffusion time of each surfactant, t_D, is introduced in order to determine the general applicability of the diffusion approximations. In the case of Triton X-100, the long time approximation is valid, and the ratio of t_a/τ_D is found to be much greater than one. In the case of Span 80, the short time approximation provides a good fit to the experimental data, and the ratio t_a/τ_D is found to be on the order of unity or less. A consideration of experimental data found in the literature for other surfactants leads to the general conclusion that the ratio t_a/τ_D is useful in characterising diffusion-controlled adsorption of surfactants.     

Formulation of ultralow interfacial tension systems using extended surfactants

Inspired by the concept of lipophilic and hydrophilic linkers, extended surfactants have been proposed as highly desirable candidates for the formulation of microemulsions with high solubilization capacity and ultralow interfacial tension (IFT), especially for triglyceride oils. The defining characteristic of an extended surfactant is the presence of one or more intermediate-polarity groups between the hydrophilic head and the hydrophobic tail. Currently only limited information exists on extended surfactants; such knowledge is especially relevant for cleaning and separation applications where the cost of the surfactant and environmental regulations prohibit the use of concentrated surfactant solutions. In this work, we examine surfactant formulations for a wide range of oils using dilute solutions of the extended surfactant classes sodium alkyl polypropyleneoxide sulfate (R-(PO) _x −SO₄Na), and sodium alkyl polypropyleneoxide-polyethyleneoxide sulfate (R-(PO) _y -(EO) _z −SO₄Na). The IFT of these systems was measured as a function of electrolyte and surfactant concentration for polar and nonpolar oils. The results show that these extended surfactant systems have low critical micelle concentrations (CMC) and critical microemulsion concentrations (CμC) compared with other surfactants. We also found that the unique structure of these extended surfactants allows them to achieve ultralow IFT with a wide range of oils, including highly hydrophobic oils (e.g., hexadecane), triolein, and vegetable oils, using only ppm levels of these extended surfactants. It was also found that the introduction of additional PO and EO groups in the extended surfactant yielded lower IFT and lower optimum salinity, both of which are desirable in most formulations. Based on the optimum formulation conditions, it was found that the triolein sample used in these experiments behaved as a very polar oil, and all other vegetable oils displayed very hydrophobic behavior. This unexpected triolein behavior is suspected to be due to uncharacterized impurities in the triolein sample, and will be further evaluated in future research.     

Dynamic surface tension of aqueous surfactant solutions. 6. Compounds containing two hydrophilic head groups and two or three hydrophobic groups and their mixtures with other surfactants

Dynamic surface tensions (γ_t)—measured by the maximum bubble pressure method—of some surfactants containing two hydrophilic (sulfonate) groups and two or three hydrophobic groups in the molecule (“gemini surfactants”), and of their mixtures with a nonionic surfactant or an amine oxide, have been measured at 25°C in 0.1 M NaCl. Linearity of the plots of surface pressure vs. square root of the surface age indicated that the systems studied were all diffusion-controlled. For the individual surfactant systems, the apparent diffusion coefficient decreases with an increase in the number of alkyl chains and the bulkiness of the surfactant molecules. For the mixtures, when interaction between the two surfactants is weak, γ_t at short times (t<1s) is close to that of the component with the lower surface tension; at longer times, it is closer to that of the component with the lower equilibrium surface tension. When interaction is strong, γ_t at short times is greater than that of either component. The molar ratio at which maximum effect on γ_t is observed depends upon the strength of the interactions between the two surfactants.     

Classification of global fluid-phase equilibrium behaviors in binary systems

The study of phase equilibria is one of the most important sources of information about the nature of intermolecular forces in liquids and their mixtures and is of the highest importance for designing and optimizing processes. Many of the main features of vapor–liquid and liquid–liquid phase behavior were well characterized experimentally during the early part of the 20th century, and many equations of state were developed to reproduce the many types of phase diagrams observed for binary systems. In spite of the quasi-infinite number of possible configurations and rearrangements of fluid–fluid equilibrium phase diagrams, this paper presents a near-exhaustive classification scheme of fluid phase equilibria in binary systems. It starts from the one proposed by Van Konynenburg and Scott and brings it up-to-date by detailing the progress carried out on this topic since their classification scheme was first proposed. The second part of this paper is devoted to describing the transitions between the various types of systems.     

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。     

Water diffusion studies in polyimide thin films

The water diffusion behaviors and activation energies of PDA- and ODA-based polyimide thin films were quite dependent on both the chemical structure and the morphological structure in the films. The water diffusion coefficients of polyimide thin films increased with increasing temperature. The activation energies varied in the range of 5.81 to 9.27 kcal/mol and were relatively higher for the PDA-based polyimide thin films than for the corresponding ODA-based polyimide thin films. For the PDA- and ODA-based polyimide films, the differences in the morphological structures and the chemical affinity to water molecules might be reflected directly on the water diffusion behaviors. The PDA-based polyimide films exhibited a relatively more ordered morphological structure (high crystallinity and good in-plane orientation) than that of the corresponding ODA-based polyimide thin films, which may serve as impenetrable obstacles for the water diffusion in the out-of-plane direction. Consequently, it may lead to a relatively slower water diffusion and high activation energy in the PDA-based polyimide thin films. Additionally, the PDA-based polyimide films with relatively lower chemical affinity showed relatively low diffusion coefficients and high activation energies. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 82: 731–737, 2001     

Vapor liquid equilibrium constants through a non-equation of state approach: Methane-free aliphatic binary systems

Using vapor liquid equilibrium measurements available in the literature for the three binaries of the system ethane—n-butane—n-heptane, correlations have been developed that predict K-constants for other aliphatic binary mixtures, not containing methane. This approach does not involve the use of an equation of state, but utilizes fundamental properties associated with the pure state components and the critical pressure of the mixture. This method produces for seven additional binary systems, K-values that are in good agreement with experimental measurements, and particularly in the vicinity of the critical point.