The Properties of Binary Mixtures of Ethoxylated Octyl Phenols with Ethoxylated Fluorinated Alkanols at the Water/Air Interface

Abstract  

Surface tension measurements were carried out for systems containing binary mixtures of ethoxylated tert-octylphenols (with an average of 10 or 16 ethylene oxide groups—HC8PEO10 and HC8PEO16, respectively) with perfluorinated n-alcohol ethoxylates (fluoropentanol with an average of 10 ethylene oxide groups FC5EO10, and fluorohexanol with an average of 14 ethylene oxide groups FC6EO14). The obtained results and calculations indicate that fluorinated surfactants have the better efficiency and effectiveness in the reduction of surface tension of water that the hydrocarbonated alkyl phenol ethoxylates and that their mole fraction in the mixed monolayer at water–air interface for mixtures containing a 0.2 molar fraction of fluorinated surfactants in bulk phase is considerable higher than in the bulk phase. At concentrations of mixtures corresponding to saturated monolayer at water-air interface there is a synergetic effect in the reduction of g_LV \gamma_{\rm LV} for a mixture of HC8PEO16 + FC5EO10 at a 0.2 molar fraction of HC8PEO16; however, taking into account the lowest value of the molecular interaction parameter for mixed micelles calculated on the basis of Rosen approach, the result is that the best synergism takes place for mixture of HC8PEO16 + FC6EO14 at a 0.2 molar fraction of HC8PEO16. Moreover, the ability of the mixed monolayer formation relative to the mixed micelle formation varies with the concentration and composition of the studied mixtures.     

非离子Gemini表面活性剂分子在水中的聚集行为

通过实验和耗散粒子动力学模拟相结合的方法,研究了非离子型Gemini表面活性剂在水溶液中的聚集行为和表面活性剂分子在水-气界面的分布情况。结果表明:10个环氧乙烷(EO)的α,α'-[2,4, 7, 9-四甲基-5-癸炔-4, 7-二醇]双[ω-羟基-聚(环氧乙烷)](S-10)的单体和团簇共存于低浓度溶液中。随着浓度的增加,表面活性剂分子聚集成球状胶束且尺寸增大;当球状胶束的尺寸增加到一定程度时,它们不能稳定存在并聚集成棒状胶束。在水-气界面处,表面活性剂分子或垂直或水平分布,但是随着浓度的增加,疏水基团垂直插进空气,而EO段在水中呈不规则的锯齿形分布。随着EO链段长度的增加,S-4、S-10和S-30的最小吸附分子截面积逐渐增大,这就是随着表面活性剂的EO段长度增加而润湿性降低的原因。实验与模拟相结合的方法为研究非离子Gemini表面活性剂的聚集行为提供了新的思路,通过模拟结果可以快速判断实验的准确性。     

Interfacial Tensions of Ethoxylated Fatty Acid Methyl Ester Solutions Against Crude Oil

The dynamic interfacial tension (IFT) of ethoxylated fatty acid methyl ester solutions against n‐alkanes, kerosene, and diluted heavy oil have been investigated by spinning drop interfacial tensiometry. The influences of ethylene oxide (EO) groups and alkyl chain length on IFT were investigated. The experiment results show that the water solubility decreases with an increase in alkyl chain length or a decrease in EO groups. The ability to lower the interfacial tension against hydrocarbons improves with both increasing alkyl chain length and EO group at the best hydrophilic‐lipophilic balance, which can be attributed to the enhancement of the interfacial hydrophobic interactions and the rearrangement of interfacial surfactant molecules. The mixed adsorption of surfactant molecules and surface‐active components may reduce IFT to a lower value. C₁₈=E₃ shows the best synergism with surface‐active components. However, the IFT values against pure crude oil are obviously higher than those against hydrocarbons, which may be caused by the nature of heavy oil.     

Effect of strain on the properties of an ethylene–octene elastomer with conductive carbon fillers

Composites that incorporate a conductive filler into an ethylene–octene (EO) elastomer matrix were evaluated for DC electrical and mechanical properties. Comparing three types of fillers (carbon fiber, low structure carbon black, and high structure carbon black), it was found that the composite with high structure carbon black exhibited a combination of properties not generally achievable with this type of filler in an elastomeric matrix. A decrease in resistivity at low strains is unusual and has only been reported previously in a few instances. Reversibility in the resistivity upon cyclic deformation is a particularly unusual feature of EO with high structure carbon black. The mechanical and electrical performance of the high structure carbon black composites at high strains was also impressive. Mechanical reinforcement in accordance with the Guth model attested to good particle–matrix adhesion. The EO matrix also produced composites that retained the inherent high elongation of the unfilled elastomer even with the maximum amount of filler (30% by volume). The EO matrix with other conducting fillers did not exhibit the exceptional properties of EO with high structure carbon black. Composites with carbon fiber and low structure carbon black did not maintain good mechanical properties, generally exhibited an increase in resistivity with strain, and exhibited irreversible changes in both mechanical and electrical properties after extension to even low strains. An explanation of the unusual properties of EO with high structure carbon black required unique features of both filler and the matrix. The proposed model incorporates the multifunctional physical crosslinks of the EO matrix and dynamic filler–matrix bonds. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 76: 894–905, 2000     

橡胶硫化活性剂氧化锌在轮胎胎侧胶中的应用

对比分析了间接法氧化锌和纳米氧化锌分别应用于胎侧配方后对于胎侧胶料性能的影响.结果表明,纳米氧化锌因具有颗粒粒径小、比表面积大的特点,同时具有界面、小尺寸、隧道三种效应,可显著提高活化效率,对次磺酰胺类促进剂有较大的吸附作用;纳米氧化锌添加到胎侧胶料配方,橡胶高聚物大分子链的运动性被迟滞,与硫化体系的反应能力降低,生产...     

脂肪醇乙氧基化物的环氧乙烷加合数对非离子/阴离子表面活性剂混合体系洗涤力的影响

研究了在非离子表面活性剂／阴离子表面活性剂／电解质的混合体系中,直链脂肪醇乙氧基化的ＥＯ数对体系洗涤力的影响效果,并用相转移化温度（ＰＴＴ）和油／水界面张力（ＩＦＴ）的观点对实验结果进行了解释,研究表明,随着体系中非离子与阴离子表面活性剂相对含量的增大,为达到最大洗涤力,非离子表面活性剂的ＥＯ数也需随之增大;随着体系中电解质含量的增大,最佳ＥＯ数也需随之增大,但前者的影响效果远高于后者。     

The energetics of surfactant adsorption at the air-water interface

The standard free energy, enthalpy, and entropy changes (ΔG, ΔH, and ΔS, respectively) for the adsorption at the air-water interface of a commercial ethylene oxide (EO) adduct of straight chain nonylphenol from monomer solution at the critical micelle concentration (CMC) have been calculated from surface tension-concentration data at 21C–45C using the Gibbs equation, the standard free energy change equation ΔG=−RT (In interfacial monomer concentration/CMC), and the Gibbs-Helmholtz equation which gave ΔH directly from the slope of the (ΔG/T) vs (1/T) function. The CMC and surface tension at the CMC (γCMC) decreased, and −ΔG and molecular area increased slightly, with increasing temperature. The ΔH and ΔS values were positive, and appear explainable by the postulations applied to micellization. At ambient temperature (28C) an increase in the (EO) mol ratio of straight chain nonylphenol and C₁₃ secondary alcohol ethoxylates resulted in increases of CMC, γCMC, and molecular area, and slight decreases in −ΔG. A comparison of the 9 (EO) mol ratio adducts of C₁₃ straight chain primary and secondary alcohols showed that the CMC and molecular area of the secondary alcohol ethoxylate were larger, and the γCMC and −ΔG smaller, than the corresponding values of the primary alcohol ethoxylate.     

Tuning Interfacial Activity of Polymeric Resin–Surfactant/<Emphasis Type="Italic">n</Emphasis>-Alcohol Solution Interactions

Measurements of surface tension were carried out for several aqueous solutions of different amphiphilic systems. This research studied the interaction between two polymeric resins (more structure definition) (PR) and nonyl phenol ethoxylates (NP) with degrees of ethoxylation varying from 10 to 20 ethylene oxide groups. The results show that in mixtures of PR and NP₂₀EO, the adsorption on the surface was lower, with the molecules tending to remain within the liquid. On the other hand, mixtures of PR and NP₁₀EO have resulted in greater surface adsorption. The effect of the added alcohols was to tune the interfacial activity of the PR as function of the PR and alcohol concentrations. The general tendency of the surface tension curves to decrease with increasing PR/alcohol concentration in solutions was not significantly modified with the addition of alcohols; however, the surface tension values changed due to the addition of alcohols and a model is proposed to explain these changes, as they depend on both alcohol chain length and the PR/alcohol concentration. An emulsion stability test was performed on polymeric resins–surfactant systems to determine the correlation between their surface properties. Nonionic surfactants present in these mixtures are mainly responsible for the emulsion stability. It was concluded that mixtures of the less hydrophilic PR (PR_B) with NP₁₀EO have good interfacial properties, including a high interfacial concentration and a low critical micellar concentration.     

活性炭变压吸附回收环氧乙烷装置排放气中的乙烯

以活性炭为吸附剂，对工业环氧乙烷装置排放气中乙烯的回收进行了研究。测定了环氧乙烷装置排放气中主要组分的吸附等温线及脱附性能，发现活性炭对乙烯的吸附量较高，与氧气、氮气和氩气等组分的分离度较大。在此基础上，研究了活性炭的变压吸附性能，在常规真空脱附工艺条件下，乙烯的回收率较低，但通过提高脱附真空度或进行甲烷反向吹扫，可以大大提高乙烯回收率和惰性气体的脱附率。     

Impact of molecular structure on the performance of methyl ester ethoxylates

Methyl ester ethoxylates are a new class of ethylene oxide (EO)-derived surfactants. Little is known about the impact of structural variations on their performance properties. The effects of carbon chain length, EO content, the degree of unsaturation of the methyl ester feedstock, and feedstock purity were examined for their impact on both physical properties and surfactant performance properties. Physical properties examined included surface properties (surface tension, critical micelle concentration, surface excess adsorption), melting point, water solubility, viscosity, foam stability, color, clarity, and odor. The impact of molecular structure on performance was examined for various applications, including laundry detergents, dishwashing detergents, and hard-surface cleaners. Presented at the AOCS Annual Meeting & Expo, May 1997, Seattle, Washington.     

Optimization of nonionic surfactants for hard-surface cleaning

The hard-surface cleaning performance of various nonionic homologs was evaluated as a function of carbon chain length, ethylene oxide (EO) content, blending and concentration. Results show carbon chain length to be very important to hard-surface cleaning. Performance significantly increases as carbon-chain length decreases, probably as a result of an increase in solvency properties as carbon chain length is decreased. EO content is also important, particularly if nonionics with longer carbon chain lengths are used. Surfactant concentration (dilution) has little effect on the optimum ethylene oxide content but significantly affects the optimum carbon chain length of the hydrophobe. With 5% homolog solutions, the optimally performing nonionic contains a C6 hydrophobe, but with 0.2% solutions, the optimal carbon chain length is shifted to the C8–C10 range. This is thought to result from a trade-off between the surfactant and solvent properties of the nonionic. Overall results show the optimal nonionic for hard-surface cleaning to consist of a blend of C6, C8 and C10 alcohols ethoxylated to a 50% EO level. Commonly used surfactant systems, e.g., alkylphenol ethoxylates and alkylphenol ethoxylate (APE)-butyl cellosolve (BC) blends, were also examined. Results show that alkylphenol ethoxylates give relatively poor performance compared with lower molecular weight linear nonionics because of the large size of their hydrophobe. Under concentrated use, a synergism does exist between APE and BC, but under dilute conditions, the addition of BC is ineffective. BC does not help the performance of low molecular weight nonionics. Surfactant-soil diffusion studies indicate that surfactant penetration of the soil may be the primary mechanism involved in the hard-surface cleaning of solid soils. Presented May 10, 1983, at the 74th Annual Meeting of the AOCS, Chicago, IL.     

Adsorption of carbon dioxide using polyethyleneimine modified silica gel

To find an ideal adsorbent for carbon dioxide capture, a new polyethyleneimine modified silica gel material was synthesized with a simple procedure. Three silica gel materials with various particle sizes (15, 25 and 40–63 μm) were prepared and functionalized with polyethyleneimine. The carbon dioxide adsorption amounts of modified silica gel and non-modified silica gel were calculated using a mass balance equation at three different temperatures (298.15, 308.15 and 318.15 K), respectively, and the influence of gas pressure and particle size on adsorption was discussed. Experimental data showed that the carbon dioxide adsorption capacity of modified silica gel was better than non-modified silica gel, and the adsorption capacity gradually decreased with increasing particle size. The smaller particle size (15 μm) PEI modified silica gel had the largest adsorption capacity, at 298.15 K, and the adsorption amounts of various particle sizes of PEI-silica better fit the Langmuir isotherm model.     

分子动力学模拟研究两亲聚合物与疏水纳米粒子自组装核-壳结构

基于Martini力场采用粗粒化分子动力学模拟研究了Pluronic嵌段共聚合物在疏水纳米表面自组装膜结构,考察了Pluronic嵌段共聚合物结构对自组装单分子膜结构的影响。模拟结果发现Pluronic聚合物在疏水纳米表面自组装形成了以纳米材料为核,聚合物为壳的特殊核-壳结构。聚合物的浓度和结构都会影响该壳层结构,在浓度较低时,聚合物EO嵌段卷曲地附着在疏水纳米颗粒表面,类似形成层状的壳层结构;随着浓度的提高,EO嵌段伸向溶剂相,形成星形自组装膜结构。增加Pluronic共聚物相对分子质量,吸附在纳米材料的聚合物壳层厚度也逐渐增加。随着聚合物PO摩尔的增加,吸附在纳米材料表面的PO嵌段由“S”形或“W”形吸附逐渐变成“U”形吸附。这可能因为随着聚合物浓度的提高,有限的纳米颗粒表面不足以提供足够多的吸附位点导致聚合物吸附构型转变。     

Chromium electrodeposition from [BMIm][BF<Subscript>4</Subscript>] ionic liquid

The electrodeposition of black chromium coatings from ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate with chromium chloride, and the chemical composition of the deposits are discussed in this article. The UV–Vis spectra recorded for chromium(III) species in 1-butyl-3-methylimidazolium tetrafluoroborate suggest that along with the chromium(III) complexes containing three ligands, there are some amounts of chromium species containing four ligands in the bath employed. The cathodic process of chromium electrodeposition in the employed ionic liquid is complicated by the electrochemical reduction of water molecules, which is followed by chemical disintegration of tetrafluoroborate ions. The surface morphology of black chromium films deposited potentiostatically (–1.5 to −2.0 V) at 85 °C shows nodules and microcracks increasing in size with cathodic potential. Analysis of the X-ray photoelectron spectra recorded from surface to depth of the deposit has shown that the black oxide-rich chromium coating consists of chromium in both oxide and metallic states with small impurities of other elements (fluorine, boron, carbon and nitrogen) and the surface is covered with a thin layer of organic substances. The results of this study show that 1-butyl-3-methylimidazolium tetrafluoroborate may be considered as a promising substitute of toxic Cr(VI) baths for black chromium plating.     

Ethylene oxide oligomer distribution in nonionic surfactants via high performance liquid chromatography (HPLC)

A high performance liquid chromatography (HPLC) method using adsorption columns combined with linear gradient elution has been developed for the determination of ethylene oxide (EO) distribution in nonionic surfactants. The quantitative ethoxylate adduct distribution in single-carbon-number and mixed-carbon-number primary alcohol-based samples can be obtained. The HPLC method is also applicable for determining the molar EO distributions in diverse ethylene oxide adduct compounds such as alkylphenol ethoxylates, branched alcohol ethoxylates and secondary alcohol ethoxylates. Nonionic surfactant samples containing adducts up to 25 mol have been successfully separated and the individual adducts quantitated.     

活性炭吸附法处理乙烯废碱液的研究

以活性炭为吸附剂处理乙烯废碱液,通过单因素实验,考查了吸附时间、吸附温度、活性炭粒度、活性炭投加量、废碱液pH对硫去除率的影响。吸附法处理乙烯废碱液的最佳工艺条件:吸附时间50 min、吸附温度25℃、活性炭粒度20~40目、活性炭投加量1.8 g、乙烯废碱液pH为3。在此条件下可使20 mL乙烯废碱液中硫浓度由1113.25 mg/L降到1.98 mg/L,硫去除率达99.82%,COD浓度由800000 mg/L降到5600 mg/L,COD去除率达99.9%。     

Surface tension of Nanofluid-type fuels containing suspended nanomaterials

ABSTRACT: The surface tension of ethanol and n-decane based nanofluid fuels containing suspended aluminum (Al), aluminum oxide (Al2O3), and boron (B) nanoparticles as well as dispersible multi-wall carbon nanotubes (MWCNTs) were measured using the pendant drop method by solving the Young-Laplace equation. The effects of nanoparticle concentration, size and the presence of a dispersing agent (surfactant) on surface tension were determined. The results show that surface tension increases both with particle concentration (above a critical concentration) and particle size for all cases. This is because the Van der Waals force between particles at the liquid/gas interface increases surface free energy and thus increases surface tension. At low particle concentrations, however, addition of particles has little influence on surface tension because of the large distance between particles. An exception is when a surfactant was used or when (MWCNTs) was involved. For such cases, the surface tension decreases compared to the pure base fluid. The hypothesis is the polymer groups attached to (MWCNTs) and the surfactant layer between a particle and the surround fluid increases the electrostatic force between particles and thus reduce surface energy and surface tension.     

Synthesis and characterization of thermo‐ and pH‐sensitive block copolymers bearing a biotin group at the poly(ethylene oxide) chain end

A poly(ethylene oxide)‐block‐poly(dimethylamino ethyl methacrylate) block copolymer (PEO‐b‐PDMAEMA) bearing an amino moiety at the PEO chain end was synthesized by a one‐pot sequential oxyanionic polymerization of ethylene oxide (EO) and dimethylamino ethyl methacrylate (DMAEMA), followed by a coupling reaction between its PEO amino and a biotin derivative. The polymers were charac terized with ¹H NMR spectroscopy and gel permeation chromatography. Activated biotin, biotin‐NHS (N‐hydroxysuccinimide), was used to synthesize biotin‐PEO‐PDMAEMA. In aqueous media, the solubility of the copolymer was temperature‐ and pH‐sensitive. The particle size of the micelle formed from functionalized block copolymers was determined by dynamic light scattering. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 3552–3558, 2006     

Oxyethylated sulfonamides as nonionic soil wetting agents

Various N-alkylbenzenesulfonamides of the type RφSO₂NHR′, where R is t-butyl, or hydrogen and R′ is decyl, octyl, t-octyl, 2-ethylhexyl, hexyl, and butyl, were treated with ethylene oxide (EO) to yield polydisperse adducts RφSO₂ N(R′)(EO)_xH where x is any integer from 2 to 20. Each series of adducts exhibited a range of properties and water solubility. Wetting ability, surface tension, cloud point, and hydrophilic-lipophilic balance (HLB) were related to structure and EO content to determine the most efficient wetting agent for peat moss and cotton skeins. Optimum wetting properties were found for adducts containing 5–10 EO units and in particular with t-C₄ H₉φSO₂N(t-C₈H₁₇)(EO)_xH. This EO chain-length region corresponded to cloud points of 25°, minimal surface tensions, and HLB values 10–12. Agricultural Research Service, U.S.D.A.     

Finite element analysis of TGO thickness on stress distribution and evolution of 8YSZ thermal barrier coatings

According to the experimental research results of the thermally grown oxide (TGO) layered growth during the pre-oxidation process of 8 wt.% yttria-stabilized zirconia thermal barrier coating (TBC), a two-dimensional sinusoidal TC/bonding coat (BC) curve interface model of the longitudinal section of TBCs based on finite element simulation was constructed; the thickness and composition of the TGO layer relative to the TC/BC curve interfacial stress distribution and its evolution during the thermal cycling process were studied. The results show that when the TGO layer uses α-Al₂O₃ as the main oxide (black TGO), the thicker the black TGO layer, the more uniform the stress distribution of the TC/BC interface. When the TGO layer is dominated by spinel-structured Co and Cr oxides (gray TGO), the stress “band” of the TC/BC interface is destroyed; it shows the alternating phenomenon of tensile stress zone and compressive stress zone, and after the rapid random growth of TGO, the concentrated tensile stress increased by a large jump. Affected by the thickness of the prefabricated black TGO layer, there is a limit peak in the thickness of the black TGO layer, the normal stress at the TC/BC boundary is minimized, and the magnitude of the stress change is also minimized.