NEW SURFACTANTS FOB SOLUBLE EXTREME PRESSURE CUTTING OILS

The use of nonionic and anionic surfactants is common in soluble cutting oils to facilitate spontaneous emulsification and to keep the formulation stable. Various additives are also introduced in order to achieve high pressure stability, better resistance to high sheers, minimum corrosion and other related properties. Tailor-made surfactants into which specific functional groups are introduced into the hydrophobic chain are of special interest mainlv if extreme pressure (EP) properties can be improved. Those surfactants will help to replace part of the additives and will reduce the cost of the formulation. Incorporation of halogens (chlorine, bromine) to the hydrophobic tail of ethoxylated nonylphenols; sorbitan esters of fatty acids, ethoxylated oleyl alcohols and polyglycerol esters has been carried out. The new surfactants have high specific gravities and therefore can minimize creaming of the emulsion and will improve the EP properties of the soluble cutting oils. Functionalization of the surfactants did not retained the emulsion stability, yet reduced the creaming and the cost of the formulation. It has been also shown that the lubrication properties e.g. the resistance to load and torque have been improved.     

From the microscopic to the mesoscopic properties of lyotropic reverse hexagonal liquid crystals

In the present study we aimed to explore a correlation between the microstructural properties of the lyotropic reverse hexagonal phase (HII) of the GMO/tricaprylin/phosphatidylcholine/water system and its mesoscopic structure. The mesoscopic organization of discontinuous and anisotropic domains was examined, in the native state, using environmental scanning electron microscopy. The topography of the HII mesophases was imaged directly in their hydrated state, as a function of aqueous-phase concentration and composition, when a proline amino acid was solubilized into the systems as a kosmotropic (water-structure maker) guest molecule. The domain structures of several dozen micrometers in size, visualized in the environmental scanning electron microscopy, were found to possess fractal characteristics, indicating a discontinuous and disordered alignment of the corresponding internal water rods on the mesoscale. On the microstructural level, SAXS measurements revealed that as water content (Cw) increases the characteristic lattice parameter of the mesophases increases as well. Using the water concentration as the mass measure of the mixtures, a scaling relationship between the lattice parameter and the concentration was found to obey a power law whereby the derived fractal dimension was the relevant exponent, confirming the causal link between the microscopic and mesoscopic organizations. The topography of the HII mesophase was found to be affected by the microstructural parameters and the composition of the samples. Thermal analysis experiments involving these systems further confirmed that the behavior of water underpins both microscopical and mesoscopic features of the systems. It was shown that both the swelling of the lattice parameter and the mesoscopic domains is correlated to the bulk water concentration in the water rods.     

Tiltan

We prove the consistency of ? with the negation of Galvin's property. On the other hand, we show that superclub implies Galvin's property. We also prove the consistency of ${?}_{{\kappa }^{+}}$ with ${\mathfrak{s}}_{\kappa }>{\kappa }^{+}$ for a supercompact cardinal κ.     

High-resolution NMR "chromatography" using a liquids spectrometer

NMR spectroscopy is an excellent tool for the structural analysis of pure compounds. However, for mixtures it performs poorly because of overlapping signals. Diffusion can be used to separate compounds of widely differing molecular weight but the amount of separation is usually insufficient.Addition of a solid medium, analogous to the stationary phase in chromatography, can preferentially slow the diffusion of some components of a mixture permitting separation in the diffusion dimension. However, this would usually require a solid-state NMR spectrometer otherwise the signals would be too broad.Susceptibility matching the solvent to the solid medium yields a spectrum with narrow signals allowing the measurement of a DOSY spectrum with enhanced separation in the diffusion dimension.     

NMR chromatography using microemulsion systems

NMR spectroscopy is an excellent tool for structural analysis of pure compounds. However, for mixtures, it performs poorly because of overlapping signals. Diffusion ordered NMR spectroscopy (DOSY) can be used to separate the spectra of compounds with widely differing molecular weights, but the separation is usually insufficient. NMR "chromatographic" methods have been developed to increase the diffusion separation but these usually introduced solids into the NMR sample that reduce resolution. Using nanostructured dispersed media, such as microemulsions, eliminates the need for suspensions of solids and brings NMR chromatography into the mainstream of NMR analytical techniques. DOSY was used in this study to resolve spectra of mixtures with no increase in line-width as compared to regular solutions. Components of a mixture are differentially dissolved into the separate phases of the microemulsions. Several examples of previously reported microemulsions and those specifically developed for this purpose were used here. These include a fully dilutable microemulsion, a fluorinated microemulsion, and a fully deuterated microemulsion. Log(diffusion) difference enhancements of up to 1.7 orders of magnitude were observed for compounds that have similar diffusion rates in conventional solvents. Examples of commercial pharmaceutical drugs were also analyzed via this new technique, and the spectra of up to six components were resolved from one sample.     

Newly designed polysiloxane-graft-poly (oxyethylene) copolymeric surfactants: preparation,surface activity and emulsification properties

Two sets of comb-grafted polymeric surfactants based on poly-(methylhydrogen siloxane) (PHMS) and/or poly(dimethylsiloxane) (PHMS-PDMS) were prepared by sililation of the active Si-H group with an active omega-vinyl group of specially designed undecenoic-polyethyleneglycol esters (UPEG) to form newly-designed polysiloxane-grafted-polyethyleneglycol comb-copolymeric surfactants.The hydrophilic moieties are hooked to the hydrophobic backbone through a spacer (undecenoic acid). The variations in the surfactants' structures were in the length and density of the grafted hydrophilic moieties, the chain length (DP) and nature of the hydrophobic backbone.The first 12 different polymeric surfactants (set 1), termed PHMS-UPEG, were found to be ineffective emulsifiers with limited ability to stabilize oil-in-water emulsions. The second set of surfactants, named PHMS-PDMS-UPEG comb-grafted copolymers, significantly reduced the oil-water interfacial tension and effectively stabilized several types of oil-in-water emulsions. The best emulsifier of this set (PHMS-PDMS-52-UPEG-45), seems to be the one whose anchor backbone (PHMS-PDMS) dissolves (rather than spreads) in the oil phase, and whose stabilizing moieties are sufficiently long (45 EO units) and hooked to the silicone backbone at high density (52% substitution).     

Combinatorial Aspects of the Splitting Number

This paper deals with the splitting number ${\mathfrak{s}}$ and polarized partition relations. In the first section we define the notion of strong splitting families, and prove that its existence is equivalent to the failure of the polarized relation $$\left(\begin{array}{lll}\mathfrak{s} \\ \omega \end{array} \right) \rightarrow {\left(\begin{array}{ll}\mathfrak{s} \\ \omega \end{array} \right)}^{1, 1}_{2}$$ . We show that the existence of a strong splitting family is consistent with ZFC, and that the strong splitting number equals the splitting number, when it exists. Consequently, we can put some restriction on the possibility that s is singular. In the second section we deal with the polarized relation under the weak diamond, and we prove that the strong polarized relation $$\left(\begin{array}{lll}2^{\omega} \\ \omega \end{array} \right) \rightarrow {\left(\begin{array}{ll}2^{\omega} \\ \omega \end{array} \right)}^{1, 1}_{2}$$ is consistent with ZFC, even when cf ${(2^{\omega}) = \aleph_{1}}$ (hence the weak diamond holds).     

Strong Polarized Relations for the Continuum

We prove that the strong polarized relation ${\left(\begin{array}{ll} 2^\mu\\ \mu \end{array}\right)\rightarrow \left(\begin{array}{ll} 2^\mu\\ \mu \end{array}\right)^{1,1}_2}$ is consistent with ZFC. We show this for ${\mu = \aleph _0}$ , and for every supercompact cardinal???. We also characterize the polarized relation below the splitting number.     

Sugar-Ester Nonionic Microemulsion: Structural Characterization

Surfactants containing sugar components and fatty acids satisfy the quality standards for food application. The food grade sugar ester in this study is a commercial sucrose monoester of stearic acid (abbreviated SES), the oil phase consists of a 1:1 mixture of n-tetradecane and l-butanol. The originally planned food grade oil, a medium chain triglyceride, is substituted by tetradecane because tetradecane is available as a fully deuterated product, which is necessary for some structural investigations. The investigated system is solid at room temperature, but liquefies and structures into a homogeneous microemulsion when heated to above 37 degrees C. The structural characterization of such microemulsions is the aim of this work. The established methods for this purpose are scattering methods, such as small-angle scattering of X-rays and neutrons and dynamic light scattering. These scattering techniques can be used to obtain valuable information on the size, shape, and internal structure of colloids and complex fluids. We started our investigation with the pseudobinary system SES, tetradecane and l-butanol, varying the SES content. The scattering results show that the sugar ester form inverse globular micelles in the oil phase. The size of these micelles is about 6 nm. While the size is nearly constant in a wide SES concentration regime (5 up to 40% surfactant), the volume or aggregation number increases significantly with SES. This is explained by an increasing replacement of l-butanol molecules by sugar-ester molecules in the micelles formed. Moreover, it can be shown that these micelles strongly overlap. Their center-to-center distance is about 3.8 nm at 40% SES at a micellar diameter of 6 nm. The micellar overlap leads to a highly reduced diffusion of the micelles as was found with dynamic light scattering. When incorporating water in the micellar core, the micelles swell up to about 10 nm and the shape of the aggregates becomes more and more elongated with higher water content. Copyright 2001 Academic Press.     

New insights into silica-based NMR "chromatography"

Silica is used as an important component for NMR “chromatography”. In this study the effect of the binding strength to silica of a variety of compounds on their diffusion rate is measured for the first time. Over two orders of magnitude of diffusion difference enhancement was obtained in the presence of silica for some compounds. An explanation of the enhancement is given that also allows one to predict the “chromatographic” behavior of new compounds or mixtures. The binding strength is divided into categories of weakly bound, singly bound and multiply bound. Carboxylates, sulfonates, and diols are found to be particularly strongly bound and to diffuse up to 2½ orders of magnitude more slowly in the presence of silica.