两性离子/阴离子表面活性剂复配体系协同作用的研究

研究了阴离子表面活性剂十二烷基硫酸钠(SDS)和两性离子表面活性剂月桂酰胺丙基甜菜碱(LMB)的形成胶束能力和降低表面张力能力的协同增效作用。发现SDS和LMB质量比在7:3至3:7范围内增效作用显著。并考察了无机盐对表面活性剂复配体系泡沫性能的影响,结果表明,低浓度的无机盐会使表面活性剂复配体系表面张力和CMC下降,发泡力上升,高浓度的无机盐会使表面活性剂复配体系发泡力下降。例如0.1mol/L的NaCl使0.0025%的复配体系表面张力下降1.73mN/m,0.17mol/L的NaCl使2%的复配体系泡沫高度上升7.2%,而NaCl浓度超过0.26mol/L后会使泡沫高度降低。     

新型树枝状非离子表面活性剂的温度与盐效应研究

以3.0代聚酰胺-胺(PAMAM G-3.0)为起始剂,合成了一种新型树枝状非离子表面活性剂。通过表面张力与稳态荧光法研究了其在水溶液和无机盐溶液中的表面性质与聚集行为,并考察了温度对其性质的影响。结果表明,随着温度的升高,表面活性剂的表面张力逐渐降低,但在研究的温度范围内,临界胶束浓度(CMC)的变化不大。当加入质量浓度为1.0%的NaCl、NaBr及Na2SO4时,均使其表面张力增大;而3种无机盐的加入,对表面活性剂CMC的影响不大。     

十二烷基苯磺酸钠/聚氧乙烯(23)月桂醚复配体系性能的研究

在35℃时通过表面张力法研究了阴离子表面活性剂十二烷基苯磺酸钠(SDBS)和非离子表面活性剂聚氧乙烯(23)月桂醚(Brij35)复配体系在不同配比下的临界胶束浓度(CMC)和降低表面张力效率方面的作用。结果表明:SDBS和Brij35的物质的量比为3∶7时,降低表面张力的效率最高,其CMC为0.2 mmol/L,明显低于单一组分;并在总物质的量浓度一定时,测定了复配体系的稳定性和润湿性。     

十二烷基三甲基氢氧化铵与烷基糖苷复配体系的表面活性和应用性能研究

研究了十二烷基三甲基氢氧化铵(DTAH)与烷基糖苷(APG-0810)复配体系的稳定性、表面张力及应用性能。结果表明,复配体系总活性物质量浓度小于70 g/L时,溶液透光率大于80%,表现出良好的稳定性,且其表面张力和临界胶束浓度(CMC)均比单一表面活性剂的表面张力和CMC低。复配体系中APG-0810的加入有利于提高十二烷基三甲基氢氧化铵的起泡性、乳化性、润湿力及净洗力。     

十二烷基三甲基氢氧化铵与烷基糖苷复配体系的表面活性和应用性能

研究了十二烷基三甲基氢氧化铵(DTAH)与烷基糖苷(APG-0810)复配体系的稳定性、表面张力及应用性能。结果表明,复配体系总活性物质量浓度小于70 g/L时,溶液透光率大于80%,表现出良好的稳定性,且其表面张力和临界胶束浓度(CMC)均比单一表面活性剂的表面张力和CMC低。复配体系中APG-0810的加入有利于提高十二烷基三甲基氢氧化铵的起泡性、乳化性、润湿力及净洗力。     

十二烷基苯磺酸钠表面张力的研究

通过表面张力的测定,研究了浓度、温度对溶液表面张力的影响,同时考察无机盐浓度对溶液表面张力的影响.结果表明:十二烷基苯磺酸钠溶液表面张力随浓度的增加、温度的升高和无机盐浓度逐渐的增大而降低,最终确定其CMC值为1.47×10-3mol/L,由于键能和水合离子半径的原因,NaCl对十二烷基苯磺酸钠表面张力的影响明显于KCl.     

烷基糖苷-十二烷基甜菜碱复配性能及无机盐的影响

考察了非离子型表面活性剂烷基糖苷(APG)和两性表面活性剂十二烷基甜菜碱(BS-12)之间的复配性能,测定了不同摩尔比的APG和BS-12复配体系的表面张力、泡沫和乳化性能,并且研究了无机盐对复配体系表面活性的影响。结果表明,与单独任一表面活性剂体系相比,APG和BS-12复配体系具有较好的表面活性,呈现明显的协同增效作用;在摩尔比为3∶7时,复配体系的表面活性最高、起泡性能最好、形成的泡沫和乳状液最稳定,协同增效作用最显著。此外,无机盐的加入提高了复配体系的表面活性,当NaCl浓度为0.03 mol·L-1时,表面张力和临界胶束浓度最小,表面活性最高;而对于无机盐,其离子价态越高,提高表面活性程度越明显;相比之下,阳离子提高复配体系表面活性的能力大于阴离子。     

脂肪酸甲酯磺酸钠与改性木质素磺酸钠的复配及其物化性能的研究

木质素磺酸盐(LS)是制浆造纸的副产物,属于高分子表面活性剂。实验通过复配的方法,研究了脂肪酸甲酯磺酸钠(MES)与改性木质素磺酸钠(GLS)复配后的表面张力以及CMC的变化;同时,通过测定乳化性能、钙皂分散力以及泡沫的性能,来进一步阐明复配体系物化性能的变化规律。研究结果表明,复配体系的水溶液表现出更低的CMC以及表面张力。同时,随着复配体系中改性木质素磺酸钠比例的增加,复配体系的乳化力升高,表现出协同效果;复配体系的起泡力几乎不受改性木质素磺酸钠的影响,但消泡速度加快。     

新型Gemini表面活性剂与SDS复配性能研究

利用K100表面张力仪测试新型阴离子Gemini表面活性剂(IXC8)与传统阴离子表面活性剂十二烷基硫酸钠(SDS)复配体系的表面张力,研究了不同温度(25、30、35、40℃)下复配体系的相互作用。结果表明,35℃时IXC8/SDS复配体系0.3∶0.7和0.7∶0.3在降低表面张力的效能方面存在增效作用;25℃时复配体系0.5∶0.5以及30℃和35℃时的全部配比在降低表面张力的效率方面存在增效作用;所有的复配体系均在形成胶束能力方面存在增效作用。     

茶皂素与十二烷基硫酸钠复配体系浮选去除废水中金属离子的研究

研究了非离子生物表面活性剂茶皂素(TS)和阴离子表面活性剂十二烷基硫酸钠(SDS)复配体系的表面活性及无机盐的影响、浮选去除废水中铜离子的处理效果。结果表明,当TS与SDS的混合比例为0.2∶1~0.3∶1时,复配体系的表面张力和临界胶束浓度均降至最低,起泡性和稳泡性均比较稳定;无机盐主要对溶液中的SDS表面活性产生影响,茶皂素性质比较稳定,基本不受影响。采用TS∶SDS=0.25∶1的复配体系进行浮选,溶液中铜离子的去除效率可以达到92%。     

Surface adsorption in the mixtures of sodium dodecylsulphate and oxyethylenated nonylphenol with different oxyethylenation degrees

The effectiveness of surface adsorption in an aqueous solution of mixtures of surfactants composed of an anionic surfactant, sodium dodecylsulphate, mixed with a nonionic one, polyoxyethylenated nonylphenol, was studied. Their behavior was compared separately. This surface adsorption was characterized by the values of the surface tension at 25°C of the total concentrations below, but near to the critical micelle concentration (CMC) in the mixtures mentioned. These were obtained as a function of different proportions of surfactants in the mixture and different chain lengths of nonionic polyoxyethylenated surfactant. The total surface excess concentrations of the surfactant mixtures and the average of molecular area per surfactant species at the aqueous solution/air interface were calculated. Finally, the values were analyzed vs the above parameters. Presented at the XDCth Meetings of CED/AID, Granada, Spain, March, 1988.     

Structural and Physicochemical Properties of a Polymerizable Surfactant Synthesized from <Emphasis Type="Italic">N</Emphasis>-Methylol Acrylamide

A new polymerizable nonionic surfactant with reactive vinyl groups has been synthesized from N‐methylol acrylamide using a two‐step procedure. The structure of the surfactant molecule was characterized by Fourier transform infrared, ¹H nuclear magnetic resonance and mass spectroscopy. The surface active properties alongside its self‐assembly properties were investigated by surface tension, electrical conductivity, and fluorescence spectroscopy measurements. As compared with other nonionic surfactants, this study showed that this polymerizable surfactant possesses slightly a higher critical micelle concentration (CMC) value and the surface tension value at CMC. The obtained CMC values were compatible among measurements, ca. 0.02–0.038 M. The evidence of micelle formation also provided by the zeta potential measurements and the obtained zeta potential values showed that the polymerizable surfactant solutions had limited stability. The hydrolysis stability and solubility of the polymerizable surfactant were also investigated. The solubility results have shown that it was soluble in polar solvents while insoluble in nonpolar solvents both at room temperature and 40 °C. The acidic and basic hydrolysis of the surfactant increased as the temperature increased and the hydrolysis stability was 180 min (basic medium) and 55 min (acidic medium) at 80 °C.     

On the measurement of critical micelle concentrations of pure and technical-grade nonionic surfactants

The critical micelle concentrations (CMC) of nine commercial nonionic surfactants (Tween 20, 22, 40, 60, and 80; Triton X-100; Brij 35, 58, and 78) and two pure nonionics [C₁₂(EO)₅ and C₁₂(EO)₈] were determined by surface tension and dye micellization methods. Commercially available nonionic surfactants (technical grade) usually contain impurities and have a broad molecular weight distribution owing to the degree of ethoxylation. It was shown that the surface tension method (Wilhelmy plate) is very sensitive to the presence of impurities. Much lower CMC values were obtained with the surface tension method than with the dye micellization method (up to 6.5 times for Tween 22). In the presence of highly surfaceactive impurities, the air/liquid interface is already saturated at concentrations well below the true CMC, leading to a wrong interpretation of the break in the curve of surface tension (γ) vs. concentration of nonionic surfactant (log C). The actual onset of micellization happens at higher concentrations, as measured by the dye micellization method. Furthermore, it was shown that when a commercial surfactant sample (Tween 20) is subjected to foam fractionation, thereby removing species with higher surface activity, the sample yields almost the same CMC values as measured by surface tension and dye micellization methods. It was found that for monodisperse pure nonionic surfactants, both CMC determination methods yield the same results. Therefore, this study indicates that precaution should be taken when determining the CMC of commercial nonionic surfactants by the surface tension method, as it indicates the surface concentration of all surface-active species at the surface only, whereas the dye method indicates the presence of micelles in the bulk solution.     

Synergistic Effect of Mixed Surfactant Systems on Foam Behavior and Surface Tension

Foam and surface tension behaviors of different ionic/nonionic surfactant solutions along with their different combinations have been investigated. Among different surfactants, sodium dodecyl sulfate showed the highest foamability over other surfactants. Mixed surfactant systems were always found to have higher foamability than the individual surfactant. It was also noticeable that nonionic surfactants show good foamability when they combine with anionic and cationic surfactants. In the case of mixed surfactant systems, nonionic/cationic surfactant mixtures showed lower surface tension than nonionic/anionic surfactant mixture due to a synergistic effect.     

Thermodynamic Parameters and Interfacial Properties of Poly(ethylene glycol)-octyl Sulfosuccinates

Surface tension of a series of poly(ethylene glycol)-octyl sulfosuccinates at different temperatures was measured, and the interfacial properties were investigated in the absence and presence of inorganic salts. Surface tension results indicate that critical micelle concentration (CMC) values of five surfactants (C8-PEG200, C8-PEG400, C8-PEG600, C8-PEG800, and C8-PEG1000) decrease as the molecular weight of polyethylene glycol (PEG) segments and the experimental temperature increases. The surface activity of the C8-PEG series changes with temperature, and the surface tension at the CMC (γ_CMC) of the C8-PEG series decreases initially and then increases as the PEG molecular weight increases. This behavior may be attributed to the dehydration of the surfactant molecules, resulting in the change of hydrophile–lipophile balance for the different EO numbers in the surfactant molecules, which form a different surface energy film at the air–water interface. Negative ΔG_m indicates that the micellization process of these surfactants is spontaneous and an entropically driven process. For the water/alkane interface, these surfactants have low interfacial activity. The interfacial tension (IFT) between these surfactants and alkanes increases first and then decreases with the increase in the molecular weight of PEG segments. After the addition of salt, the interfacial activity of the investigated surfactants increases significantly. The IFT between C8-PEG800 and 10–12 alkanes and between C8-PEG1000 and 12–16 alkanes reaches a low IFT magnitude of 10⁻² mN m⁻¹ in the presence of 0.5% CaCl₂ or the mixed inorganic salts 0.5% NaCl+0.5% CaCl₂.     

Surface Activity and Performance Properties of Gemini Salts of Linear Alkylbenzene Sulfonate in Aqueous Solution

Gemini salts of linear alkylbenzene sulfonate (LABS) were prepared by neutralization of sulfonic acid with a series of low-molecular-weight diamines in aqueous solution. The equilibrium surface activity of Gemini salts of LABS was determined by measuring the surface tension as a function of surfactant concentration to determine the critical micelle concentration (CMC), surface tension at the CMC (γ_CMC), and the area per molecule at the air-water interface (Ų). Electrical conductivity was measured as a function of surfactant concentration to determine the CMC and counterion binding. Dynamic surface tension was measured using a bubble pressure tensiometer to infer the rate at which the surfactant migrates to the air-water interface. Equilibrium interfacial tension against mineral oil was measured using a spinning drop tensiometer. Dynamic interfacial tension was measured using a drop volume tensiometer. The surface tension, CMC, and interfacial tension of Gemini salts of LABS decreased compared to monovalent organic and inorganic salts. The CMC decreases with increasing molecular weight of the diamine spacer group. Dynamic surface and interfacial tension of Gemini salts of LABS are lower than monovalent salts. The foam volume of Gemini salts of LABS was determined using a high shear blender test. The foam volume of Gemini salts of LABS is lower than monovalent salts and depends on the size of the spacer group. Hard-surface cleaning was measured using artificial soil applied to white Formica tiles. Soil removal was determined by optical reflectance as a function of abrasion cycles. Gemini salts of LABS show reduced hard-surface cleaning performance compared to monovalent salts. Detergency of different types of soils on cotton and polyester/cotton fabric was determined by optical reflectance measurements. Gemini salts of LABS show improved cleaning performance compared to monovalent salts. Cleaning performance increases with increasing molecular weight of the diamine spacer group. In situ neutralization of LABS with organic diamines is a simple and efficient way to prepare anionic Gemini surfactants for industrial scale applications.     

Effects of surface activity on aquatic toxicity of binary surfactant mixtures

The purpose of this study was to discuss the effects of surface activity on the aquatic toxicity of binary surfactant mixtures comprising anionic, nonionic, and cationic surfactants. Surface tension was measured to determine the cmc (critical micelle concentration), and acute aquatic toxicity tests were conducted on Daphnia magna to obtain 24h-EC(50) (24h 50% effective concentration). TU (toxic unit) was calculated to evaluate the toxicity of the mixture. Most of the surfactant mixtures showed no synergistic increase in the aquatic toxicity. The mixture of anionic/nonionic surfactants showed synergistic interfacial activity with decreasing cmc, but the toxicity did not increase. The surface tension of the mixture at 24h-EC(50) (γ(tox)), which was used as an indicator of the toxic concentration, decreased considerably and TU was >1, indicating decreased toxicity. γ(tox) of the anionic/anionic surfactant mixture decreased when tested with hard water (hardness of 625 ppm). γ(tox) could not be used as a toxic indicator for the anionic/cationic surfactant mixtures because they showed aquatic toxicity before their surface tension began to decrease.     

Micellization and Adsorption Behaviors of New Reactive Polymerizable Surfactants Based on Modified Nonyl Phenol Ethoxylates

The synthesis and characterization of a series of polymerizable surfactants based on alkyl phenol ethoxylate backbone and carboxylic or anhydride chain ends were investigated. Surface activities of these polymerizable surfactants were investigated to correlate their structure and their performances. The new bifunctional surfmers were prepared by reacting polyoxyethylene 4-nonyl-2-propylene-phenol nonionic reactive surfactants with maleic anhydride. The chemical structure of the prepared surfactants was characterized by ¹³C and ¹H NMR analyses. The surface activities of the modified polymerizable surfactants were measured from the adsorption isotherm measurements which were determined from the relationship between the concentrations and surface tension of surfactants in aqueous medium at different temperatures. Critical micelle concentration (CMC) values were determined for water soluble surfactants. It was found that CMC decreases with the incorporation of the anhydride and acid groups in the chemical structure of polyoxyethylene 4-nonyl -2-propylene-phenol nonionic surfactant. surface-active parameters such as area per molecule at the interface (A _min), surface excess concentration (Γ_max) and the effectiveness of surface tension reduction (π_CMC) were measured from the adsorption isotherms of the modified surfactants. Some thermodynamic data for the adsorption process were calculated and discussed. The data indicated that the new surfmers are more reactive than the simple polyoxyethylene 4-nonyl-2-propylene-phenol and more adsorbed at interfaces. We have performed a preliminary experiment to explore the emulsification efficiency of the newly synthesized reactive surfactants in equal volume oil–water emulsions. Different emulsion types and stabilities were obtained.     

Some Surface Properties of Polysorbates and Cetyl Trimethyl Ammonium Bromine Mixed Systems

Mixed surfactant solutions consisting of cationic/nonionic surfactants were prepared in different compositions of the components in aqueous solution in order to determine the surface properties. The critical micelle concentration (CMC) of aqueous solutions of the individual surfactants cetyl trimethyl ammonium bromide (CTAB) and polysorbate nonionics, and their mixtures are determined at different proportions. The results show that there is synergistic behavior in mixtures at higher mole fraction of nonionic surfactant. The effect of the alkyl chain on the CMC is also determined.