Influence of glycols on the formation of lamellar liquid crystals with an anionic surfactant,oleic acid,and water

The influence of glycol structures on the formation of lamellar liquid crystals with the physical appearance of transparent gels in formulations composed of an anionic surfactant, oleic acid, and water was investigated. The glycols studied belong to alkyl derivatives of ethylene glycol and diethylene glycol. The relationships between the ingredients of the so-called basic compositions—surfactant, oleic acid, and glycol—were optimized to form transparent gels when diluted with water. The ranges in which transparent gels existed were compared for the systems with different glycols. The most suitable glycols, as defined by the lowest surfactant content in the final transparent gels, were ethylene glycol methyl ether and especially methyl and ethyl derivatives of diethylene glycol. Formulations with 2–3% surfactant could be prepared with these glycols. These data were correlated with the polarity of the glycol structures described by means of log P (octanol/water partition coefficient). Transparent gel formation occurred for log P values ranging from approximately 0.5 to −0.5, whereas liquid crystal formation did not result from higher or lower values.     

Optimization of transparent gels for cosmetic compositions

The necessary conditions were established by which several biocompatible ingredients (phosphated oleyl ether 3 mol ethylene oxide as surfactant, oleic acid as the lipophilic ingredient, and diethylene glycol monoethyl ether and 1,2-propanediol as glycols) were combined to formulate transparent gels through dilution with water. This study was carried out at three constant levels of surfactant concentration (5, 10, and 15%), which determined in each case the appropriate ratios between the other three components to give transparent gels. These ratios were expressed as the global ratios between oleic acid and the two glycols together (ranging from 1∶9to 1∶3), whereas the internal ratios between the glycols moved in each case from 1∶0 to 0∶1. The systems with 5% of initial surfactant and a global ratio between oleic acid and the glycols of 1∶7 appeared to be the most effective for minimizing the final surfactant content. They furnished transparent gels at specified levels of water dilution, resulting in final surfactant concentrations in the range of 2–4%. Microscopic observation of the gels through polarized light showed the typical pattern of a lamellar liquid crystal structure. The mild characteristics of these gels, given their low surfactant content and the harmlessness of the other components, in addition to their attractive transparency and the rheological characteristics of plastic fluids make them suitable for application as topical formulations in the cosmetic or pharmaceutical fields.     

Hydrophobic hydration of cationic mixed micelles by alkoxyethanols in aqueous media

The conductances of hexadecylpyridinium chloride (HPyCl) + tetradecyltrimethylammonium bromide (TTAB) mixtures over the entire mole fraction range of HPyCl (α_HPyCl) were measured in aqueous binary mixtures of ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, and diethylene glycol monobutyl ether containing 10 to 30 wt% additive in their respective binary mixtures at 30°C. Each conductivity curve showed a single break over the whole mole fraction range of HPyCl + TTAB mixtures. From the break in the conductivity curve, various micellar parameters were calculated and the results were discussed on the basis of alkoxyethanol's hydrophobic hydration of the mixed micelle. The micellar parameters of HPyCl, TTAB, and of their mixtures showed a strong dependence both on the amount and on the number of repeating units of ethylene and diethylene glycol derivatives. The hydrophobic hydration was considerably higher in the case of diethylene glycol derivatives owing to the presence of an extra ether oxygen. An evaluation of the non-ideality in the HPyCl + TTAB mixtures in the presence of additives revealed that alkoxyethanols reduce the unlike surfactant monomer interactions in order to form the mixed micelles in comparison to those in pure water. It has also been observed that such interactions systematically decrease with an increase in the number of repeating units from monomethyl ether to monobutyl ether, both in the case of ethylene and diethylene glycol derivatives.     

Preparation of glycol esters of soybean oil fatty acids and their potential as coalescent aids in paint formulations

Soy oil glycol monoesters have been prepared through the transesterification of soybean oil with ethylene, diethylene, propylene, and dipropylene glycols. The molar ratio of soybean oil to glycol used in these reactions was 1∶6. The catalyst used in these reactions was lithium carbonate, 0.5%, based on soybean oil. The transesterifications were carried out at 180–190°C. The composition of soy oil glycol esters and their physical properties were determined. The soy oil glycol esters were incorporated in a water-based paint formulation as the coalescent aid, and the minimum film formation temperature was determined. The minimum film formation temperature results indicated that these esters can be used as coalescent aids in latex paint formulations to help in continuous film formation at or below room temperature.     

Synthesis and study of properties of new oligoesters based on soybean oil as potential poly(vinyl chloride) plasticizers

New compounds as potential poly(vinyl chloride) plasticizers based on soybean oil and oligoesters of adipic acid and different glycols by one-pot transesterification are synthesized. In the first step of the plasticizer synthesis oligoesters of adipic acid and diethylene glycol, triethylene glycol, or dipropylene glycol are synthesized, and then in situ in the second step, a defined amount of soybean oil is introduced. By degradation of soybean oil with oligoesters, and transesterification reaction, different compounds are obtained. Their physicochemical properties are determined by NMR, SEC, DSC, TGA, and volatility analyses. The properties of synthesized plasticizers are compared with commercial products: monomeric (DEHP) and aliphatic oligoster of adipic acid and 1,3-butanediol (H-1).     

Temperature dependence of the solubility areas for W/O microemulsions with nonionic/anionic surfactants

The solubitity areas were determined at 30, 50 and 75 C for W/O microemulsions of water and decane stabilized by sodium dodecyl sulfate or hexaethylene glycol dodecyl ether in combination with pentanol. The results showed no pronounced changes when the ionic surfactant was partly replaced with the nonionic one and revealed an excellent temperature stability in the range 30–75 C for the W/O microemulsions.     

The Interaction of Glymes with Surfactant Micelles

The critical micelle concentrations (CMC) values and counterion dissociation (α values) have been determined for a number of mixed micellar systems consisting of two typical ionic surfactants and glycol ethers (glymes) as cosurfactants, namely diethylene glycol dimethyl ether, diethylene glycol diethyl ether, triethylene glycol dimethyl ether, and tetraethylene glycol dimethyl ether. Conductance experiments were used to determine the CMC and α values of the mixed micelles as a function of glyme concentration in the aqueous mixed solvent. Favorable interactions between sodium dodecyl sulfate micelles and glyme cosurfactants were deduced from the decreases in the CMC values and the large increase in the α values of these systems as a function of increasing glyme concentration in the mixed solvents. In contrast to the anionic surfactant/glyme systems, in general, there appeared to be little favorable interactions between the surfactant and glymes when micelles of the cationic surfactant dodecyltrimethylammonium bromide were formed in water/glyme solvent systems containing an increasing amount of the glymes. The interaction of glymes with the surfactant micelles was examined closely via ¹³C nuclear magnetic resonance (NMR) chemical shifts for both surfactant and glyme carbons; these chemical shifts changes were interpreted in terms of the distribution and the localization of the glymes in the aggregates. Finally, partition constants, determined from two-dimensional diffusion-oriented spectroscopy (2D-DOSY) experiments, were used to calculate thermodynamic quantities of transfer of the glymes between the bulk phase and the self-assembled aggregates. All these results are interpreted in terms of the key contributions that both the glyme ethoxylated groups and alkyl endgroups make to the hydrophobic interactions.     

制备纳米BaSO4的W/O微乳液体系组成及稳定性

以TritonX 10 0 正己醇 环己烷 水制成W O微乳反胶团体系 ,通过测定体系的电导率和观察液晶相的出现确定相点绘制了各体系的拟三元相图 ,研究了温度、盐浓度和油相组分对W O微乳液体系稳定性的影响 .实验发现助表面活性剂与表面活性剂的配比对微乳液的稳定性有显著影响 .随着温度的升高 ,W O微乳液稳定区域减小 ,可通过升高温度对微乳液进行破乳 ;与以纯环己烷为油相的体系相比 ,油相中含有少量正己烷的体系具有更优异的性质 .所得结果为利用该W O微乳液体系制备纳米颗粒提供了基础数据     

Influence of Ionic Surfactants on the Formation of Liquid Crystals in Oleic Acid/Glycol/Water Systems

The influence of surfactant structure on the formation of lamellar liquid crystals with very low surfactant concentration was investigated for systems composed of oleic acid, diethyleneglycol ethyl ether and water. Surfactants belonging to anionic and cationic families were checked: phosphated oleyl ether 3 EO (PO₃EO), triethanolamine oleate (TEAO) and sodium lauryl ether sulphate (SLES) as anionic surfactants and two alkyl trimethylammonium bromide type (C₁₂TAB and C₁₄TAB) as cationic surfactants. For each of the surfactants, the appropriate relationships between surfactant, oleic acid and glycol to furnish lamellar liquid crystals when these basic compositions were further diluted with water were established. The appropriate ranges of dilution allowing the liquid crystal formation were also determined. These liquid crystals presented an attractive appearance because of their transparency and high viscosity, although in the beginning of its formation, a short range of less viscous compositions (so called liquid/gel compositions) appears in some cases. Through water dilution, the initial surfactant percentages are noticeably reduced being possible liquid crystals with 2–5 wt% of surfactant.

光学镜头用酸性脱墨剂研制与应用

文章所涉及酸性脱墨剂,以二氯甲烷为主溶剂,以乙二醇丁醚或二乙二醇丁醚为助溶剂,以甲酸为促进剂,加入表面活性剂十二烷基苯磺酸,并以细粒度蜡粉作为挥发抑制剂,应用于光学镜头加工过程中光学专用墨的脱除。该酸性脱墨剂已在多家光学元件生产厂家应用,具有脱墨效果好,脱墨速度快,可反复使用,不损伤光学镜头等特点。     

Properties of titanium glykolates as precursors for the synthesis of titanium dioxide

The reactions of the formation of monosubstituted titanium ethylene, diethylene, and triethylene glycolates based on the interaction of glycols with tetrabutoxytitanium in solutions were investigated. It was shown that ethylene glycol predominantly forms cyclic structures: diethylene glycol, a mixture of cyclic and linear structures, and triethylene glycol, mainly linear structures. The comparative analysis of the reaction products showed that the most promising precursor for the synthesis of TiO₂ is a titanium compound based on triethylene glycol.     

Sol-Gel负载磷钨酸催化合成乙二醇单乙醚醋酸酯

以醋酸和乙二醇单乙醚为原料,硅酸乙酯为硅源,通过溶胶-凝胶法(Sol-Gel)负载磷 钨酸为催化剂,合成了乙二醇单乙醚醋酸酯。实验结果表明:当正硅酸乙酯:水(mol／mol)=1∶4, 正硅酸乙酯:磷钨酸(W/W)=10∶1,醋酸:醇醚(mol／mol)=1．4∶1,催化剂用量为醇醚质量的 10％,带水剂甲苯用量为反应物质量的15％,反应时间为60 min时,收率可达96％以上。比较了 以硅胶直接负载磷钨酸作为催化剂的使用情况。     

Interactions of Glycols with Dodecyl Isothiouronium Cationic Surfactant on the Surface Active Parameters

Surface properties of the dodecyl isothiouronium cationic surfactant in a mixed solvent of water and polyethylene glycol of different molecular weights varied from ethylene glycol to polyethylene glycol-600 were determined using surface tension and conductivity measurements. The results showed an increase in the surface properties including critical micelle concentration, effectiveness and efficiency, compared to the surfactant in pure water as the solvent. The interaction between the cationic surfactant and the glycols was described and the molecular weight of the different glycols was rationalized.     

Structural features of poly(alkylene ether carbonate) diols and intermediates formed during their preparation

Capillary vapor-phase chromatography and carbon-13 nuclear magnetic resonance (NMR) have been used to elucidate the structure of poly(ethylene ether carbonate) diols and certain intermediates produced by the oligomerization of ethylene carbonate (EC) using monoethylene glycol (MEG) or diethylene glycol (DEG) as initiator and catalyzed by sodium stannate trihydrate. These diols are alternating copolymers of carbon dioxide and DEG which also contain smaller amounts of higher glycols as determined by comparing their ¹³C NMR spectra to the spectra of model compounds. Diethylene glycol is an important reaction intermediate and is present in steady-state concentrations. Although both 2-hydroxyethyl carbonate and 2-hydroxyethyl ether end groups are present at an intermediate stage in the reaction, only 2-hydroxyethyl ether end groups are present at high EC conversion. Molecular weight builds as a smooth function of conversion and time.     

Quantitative analysis of oil removal from cotton fabrics through thein situ formation of microemulsions by solid-state nuclear magnetic resonance

Solubilization and subsequent removal of soybean oil from cotton fabrics through thein situ formation of microemulsions were evaluated by solid-state nuclear magnetic resonance (NMR) spectrometry. Regions of water-in-oil and oil-in-water microemulsions were identified for systems that contained polyoxyethylene (60) sorbitol hexaoleate, soybean oil, and an aqueous phase composed of water/ethanol or isopropanol (80:20 wt%) at 25°C. The amount of oil removed from the cotton fabrics was determined by solid-state NMR after constructing a calibration curve relating the intensity of camphor/oil NMR signals (I_c/I_o) to their molar ratio (M_c/M_o). A precision Crockmeter (Mul-Tech Industries, New York, NY) was used to reproducibly remove soybean oil stain from cotton fabric, which was subsequently analyzed by NMR. Typically, more than 90% of the oil stain was removed after 200 revolutions of the Crockmeter finger with 2 wt% surfactant at 25°C. Increasing the amount of surfactant to 6 wt% improved soybean oil removal from the fabric to 99 wt%.     

制备纳米BaSO4的W/O微乳液体系组成及稳定性

以Triton X-100/正己醇/环己烷/水制成W/O微乳反胶团体系，通过测定体系的电导率和观察液晶相的出现确定相点绘制了各体系的拟三元相图，研究了温度、盐浓度和油相组分对W/O微乳液体系稳定性的影响.实验发现助表面活性剂与表面活性剂的配比对微乳液的稳定性有显著影响.随着温度的升高，W/O微乳液稳定区域减小，可通过升高温度对微乳液进行破乳；与以纯环己烷为油相的体系相比，油相中含有少量正己烷的体系具有更优异的性质.所得结果为利用该W/O微乳液体系制备纳米颗粒提供了基础数据.     

Influence of the glycol component in dibenzoate plasticizers on the properties of plasticized PVC films

A series of glycol dibenzoates was synthesized by transesterification of glycols with methyl benzoate. PVC films were prepared from suspension grade PVC and the dibenzoates at a constant content of the dibenzoates. The mechanical properties of the films were measured. In addition, the extractability and the absorption of various liquids was determined. The effect of the structure of the glycol component in the dibenzoates on the mechanical properties of the films and the plasticizing efficiency was investigated. Neopentyl glycol dibenzoate exhibits the highest plasticizing effect, followed by triethylene and ethylene glycol dibenzoates and the 2‐(n‐butyl)‐2‐ethyl‐1,3‐propanediol derivative. It was found that the ether linkages in the dibenzoates mainly contribute to the plasticization of PVC. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 97: 822–824, 2005     

SYNTHESIS OF UNSATURATED POLYESTER RESIN—EFFECT OF CHOICE OF REACTANTS AND THEIR RELATIVE PROPORTIONS

Unsaturated polyesters are synthesized in the laboratory by the condensation of saturated and unsaturated anhydrides with glycols. The condensate obtained is mixed with styrene monomer to get an unsaturated polyester resin formulation. The properties of the polyester resin synthesized are affected by the synthesis parameters. In this study, the parameters investigated are the effect of choice of reactants and their relative proportions. Properties such as tensile strength, tensile modulus, elongation-at-break, toughness, impact strength, surface hardness, abrasion resistance, and water absorption were tested after curing the resin. Various combinations of (a) maleic anhydride and phthalic anhydride, (b) propylene glycol and ethylene glycol, and (c) propylene glycol and diethylene glycol were used to investigate the effect on the properties of the synthesized resin. The combinations of the anhydrides and glycols that give optimum properties are identified. The results show that most of the properties are maximum at 60% maleic anhydride composition in a mixture of maleic anhydride and phthalic anhydride. Similarly, a better balance of properties is obtained when propylene glycol is mixed with 30% ethylene glycol or 20% diethylene glycol.     

Effect of Alkyl Sulfate on the Phase Behavior of Microemulsions Stabilized with Monoacylglycerols

In this study the effect of an anionic surfactant (sodium dodecyl sulfate SDS) and oils (hydrocarbons: C12–C16) on the formation and phase behavior of the systems of oil/monoacylglycerols (MAG):SDS/propylene glycol/water has been investigated. The effects of the surfactant mixture on the phase behavior and the concentration of water or oil in the systems were studied at three temperatures (50, 55, 60 °C). Electrical conductivity measurement, FT-IR spectroscopy and differential scanning calorimetry methods were applied to determine the structure and type of the microemulsions formed. The dimension of microemulsion droplets was characterized by dynamic light scattering. It has been stated that the concentration of SDS has a strong influence on the shape and extent of the microemulsion areas. Addition of an ionic surfactant to the mixture with MAG promotes an increase in the area of microemulsion formation in the phase diagrams, and these areas of the isotropic region change with the temperature. It was shown that the presence in the systems of a surfactant more hydrophilic than MAG caused an increase in water content in the microemulsions. It was found that, depending on temperature and concentration of the surfactant mixture, it was possible to obtain a W/O type microemulsion with a dispersed particles size distribution ranging from 20 to 50 nm and containing about 17–38% water in the system. Among different alkanes (from C12 to C16), hexadecane embedded microemulsions showed a maximum water solubilization capacity.     

Microcellular polymeric materials from microemulsions: Control of microstructure and morphology

The effect of a crosslinking agent on the formation of porous solids by polymerizing microemulsions formulated with monomers was investigated. Phenomenological studies were carried out to evaluate the possibility of controlling the morphology of the porous polymeric materials by using precursor microemulsions having a distinct microstructure. A microemulsion system, containing methyl methacrylate (MMA), acrylic acid (AA), the crosslinking agent ethyleneglycol dimethacrylate (EGDMA), water, and sodium dodecylsulfate (SDS) as surfactant, was studied. An identical surfactant-free system, formed using the same monomers, crosslinking agent, and water, but without surfactant, was also studied. Microemulsion samples from both these systems, having a water in oil droplet microstructure and also samples exhibiting bicontinuous microstructural characteristics, were used as precursor systems for polymerization. The morphology of the polymeric solids obtained was examined using scanning electron microscopy and thermogravimetric analysis. The results of this study indicate the possibility of forming porous polymeric solids having specifically tailored morphology and microstructure by the polymerization of monomer containing microemulsions. © 1993 John Wiley & Sons, Inc.