Polar Oil Research Articles

Organogel-Emulsions with Mixtures of β-Sitosterol and γ-Oryzanol: Influence of Water Activity and Type of Oil Phase on Gelling Capability

In this study, water-in-oil emulsions were prepared from water containing different salt concentrations dispersed in an oil phase containing a mixture of β-sitosterol and γ-oryzanol. In pure oil, the β-sitosterol and γ-oryzanol molecules self-assemble into tubular microstructures to produce a firm organogel. However, in the emulsion, the water molecules bind to the β-sitosterol molecules, forming monohydrate crystals that hinder the formation of the tubules and resulting in a weaker emulsion-gel. Addition of salt to the water phase decreases the water activity, thereby suppressing the formation of sitosterol monohydrate crystals even after prolonged storage times (∼1 year). When the emulsions were prepared with less polar oils, the tubular microstructure was promoted, which significantly increased the firmness of the emulsion-gel. The main conclusion of this study is that the formation of oryzanol and sitosterol tubular microstructure in the emulsion can be promoted by reducing the water activity and/or by using oils of low polarity.

Pickering emulsions stabilized by surface-modified Fe3O4 nanoparticles

Unmodified Fe3O4 nanoparticles do not stabilize Pickering emulsions of a polar oil like butyl butyrate. In order to obtain stable emulsions, the Fe3O4 nanoparticles were modified by either carboxylic acid (RCOOH) or silane coupling agents (RSi(OC2H5)3) to increase their hydrophobicity. The influence of such surface modification on the stability of the resultant Pickering emulsions was investigated in detail for both a non-polar oil (dodecane) and butyl butyrate in mixtures with water. The stability of dodecane-in-water emulsions in the presence of carboxylic acid-coated particles decreases as the length of the alkyl group (R) and the coating extent increase. However, such particles are incapable of stabilizing butyl butyrate-water emulsions even when the carboxylic acid length is decreased to two. However, the silane-coated Fe3O4 nanoparticles can stabilize butyl butyrate-in-water emulsions, and they also increase the stability of dodecane-in-water emulsions. Thermal gravimetric analysis indicates that the molar quantity of silane reagent is much higher than that of carboxylic acid on nanoparticle surfaces after modification, raising their hydrophobicity and enabling enhanced stability of the resultant polar oil–water emulsions.

Carbon black–clay hybrid nanocomposites based upon EPDM elastomer

The present study explored the effect of nanoclay on the properties of the ethylene–propylene–diene rubber (EPDM)/carbon black (CB) composites. The nanocomposites were prepared with 40 wt% loading of fillers, where the nanoclay percentage was kept constant at 3 wt%. As the modified nanoclay contains the polar groups and the EPDM matrix is nonpolar, a polar rubber oil extended carboxylated styrene butadiene rubber (XSBR), was used during the preparation of nanocomposites to improve the compatibility. Primarily the nanoclay was dispersed in XSBR by solution mixing followed by ultrasonication. After that EPDM-based, CB–clay hybrid nanocomposites, were prepared in a laboratory scale two roll mill. The dispersion of the different nanoclay in the EPDM matrix was observed by wide-angle X-ray diffraction (WAXD) and high resolution transmission electron microscopy. It was found that the mechanical properties of the hybrid nanocomposites were highly influenced by the dispersion and exfoliation of the nanoclays in the EPDM matrix. Thermo gravimetric analysis, scanning electron microscopy and dynamic mechanical thermal analysis was carried out for each nanocomposite. Among all the nanocomposites studied, the thermal and mechanical properties of Cloisite 30B filled EPDM/CB nanocomposite were found to be highest.

Worldwide cheap and heavy oil productions: A long-term energy model

Crude oil, natural gas liquids, heavy oils, deepwater oils, and polar oils are non-renewable energy resources with increasing extraction costs. Two major definitions emerge: regular or ‘cheap’ oil and non-conventional or ‘heavy’ oil. Peaking time in conventional oil production has been a recent focus of debate. For two decades, non-conventional oils have been mixed with regular crude oil. Peaking time estimation and the rate at which production may be expected to decline, following the peak, are more difficult to determine. We propose a two-wave model for world oil production pattern and forecasting, based on the diffusion of innovation theories: a sequential multi-Bass model. Historical well-known shocks are confirmed, and new peaking times for crude oil and mixed oil are determined with corresponding depletion rates. In the final section, possible ties between the dynamics of oil extraction and refining capacities are discussed as a predictive symptom of an imminent mixed oil peak in 2016.

Formulation Design and Experiments of Emulsion for Rolling Process of Magnesium Alloy

The formulation design and fundamental experiments of O/W type emulsions as lubricant and coolant in the hot rolling process of magnesium alloy were conducted in this work. The main components of emulsion were determined by the comparision of some candidates of base oil, polar oil additive and emulsifier in microstructure and properties, respectively. It is found that the conservation stability of emulsions is mainly dominated by the emulsifier concentration and type. The results showed that the suitable stability and microstructure was obtained by using compound emulsifier of nonionic and anionic surfactants. The feasible contents of both emulsifier and polar agents are about 10 percent, respectively.

Nano-scale structure of crude oil deposits on water-wet substrates: Dependence on aqueous phase and organic solvents

Wettability alteration of glass substrates due to displacement of the surrounding salt solution by crude oil, and its reversal via salt solution flooding, were investigated as a function of salt concentration and solution pH, and the sample preparation procedure. The resulting wettability states were analyzed by microscopy of the substrate-bound oil residues and contact angle goniometry. Atomic force microscopy of the flooded state under its salt solution showed partial coverage of the substrate by adhering oil nano-blobs. Scanning electron microscopy provides a simpler means to acquire images of residues, but the need to rinse the bulk liquids and dry can introduce preparation artifacts. Three organic solvent rinsing procedures were examined, all showing that oil residue coverage decreases with increasing NaCl concentration and pH, and also decreases after flooding to follow these same trends. However, procedures in which bulk oil was rinsed from the flooded state using the solvents decalin and heptane created extraneous deposition; removal of the salt solution by methanol better preserved the oil residues. After flooding, even the salt solution allowing greatest adsorption/deposition of polar oil components, and strongest oil-substrate adhesion, had reduced coverage to only 20%. Analogous experiments on sandstone rock supported these findings. This suggests that local wettability of reservoirs can fluctuate in response to the oil and water slowly passing through pores during oil recovery by flooding.

Interactions of hydrophilic silica nanoparticles and classical surfactants at non-polar oil–water interface

The interfacial and bulk properties of submicron oil-in-water emulsions simultaneously stabilised with a conventional surfactant (either lecithin or oleylamine) and hydrophilic silica nanoparticles (Aerosil®380) were investigated and compared with emulsions stabilised by either stabiliser. Emulsions solely stabilised with lecithin or oleylamine showed poor physical stability, i.e., sedimentation and the release of pure oil was observed within 3 months storage. The formation and long-term stability of silica nanoparticle-coated emulsions was investigated as a function of the surfactant type, charge, and concentration; the oil phase polarity (Miglyol®812 versus liquid paraffin); and loading phase of nanoparticles, either oil or water. Highly stable emulsions with long-term resistance to coalescence and creaming were formulated even at low lecithin concentrations in the presence of optimum levels of silica nanoparticles. The attachment energy of silica nanoparticles at the non-polar oil–water interface in the presence of lecithin was significantly higher compared to oleylamine in line with good long-term stability of the former compared to the sedimentation and release of oil in the latter. The attachment energy of silica nanoparticles at the polar oil–water interface especially in the presence of oleylamine was up to five-times higher compared to the non-polar liquid paraffin. The interfacial layer structure of nanoparticles (close-packed layer of particle aggregates or scattered particle flocs) directly related to the free energy of nanoparticle adsorption at both MCT oil and liquid paraffin–water interfaces.

Magnetic Pickering Emulsions Stabilized by Fe3O4 Nanoparticles

Superparamagnetic Fe(3)O(4) nanoparticles prepared by a classical coprecipitation method were used as the stabilizer to prepare magnetic Pickering emulsions, and the effects of particle concentration, oil/water volume ratio, and oil polarity on the type, stability, composition, and morphology of these functional emulsions were investigated. The three-phase contact angle (θ(ow)) of the Fe(3)O(4) nanoparticles at the oil-water interface was evaluated using the Washburn method, and the results showed that for nonpolar and weakly polar oils of dodecane and silicone, θ(ow) is close to 90°, whereas for strongly polar oils of butyl butyrate and 1-decanol, θ(ow) is far below 90°. Inherently hydrophilic Fe(3)O(4) nanoparticles can be used to prepare stable dodecane-water and silicone-water emulsions, but they cannot stabilize butyl butyrate-water and decanol-water mixtures with macroscopic phase separation occurring, which is in good agreement with the contact angle data. Emulsions are of the oil-in-water type for both dodecane and silicone oil, and the average droplet size increases with an increase in the oil volume fraction. For stable emulsions, not all of the particles are adsorbed to drop interfaces; the fraction adsorbed decreases with an increase in the initial oil volume fraction. Changes in the particle concentration have no obvious influence on the stability of these emulsions, even though the droplet size decreases with concentration.

Hepatotoxicity and Langerhans Islets Regenerative Effects of Polar and Neutral Lipids of Nigella sativa L. in Nicotinamide/streptozotocin-Induced Diabetic Rats

Abstract The extracted oil from Nigella sativa seeds is reported to be effective against various diseases and chemicallyinduced hepatotoxicity and nephrotoxicity. The effect of oral administration of Nigella sativa total, polar and neutral oils was investigated on hepatoprotective status in streptozotocin/nicotinamide (STZ-N)-induced diabetic rats. The toxicity was assessed biochemically by monitoring aspartate transaminase (AST), alanine transaminase (ALT), gamma-glutamyl transpeptitase (g-GT) and alkaline phosphatase (AP) activities as well as biluribin titre and histologically under light microscope. The study was also undertaken to evaluate the effect of oil fractions on the regeneration of pancreatic Langerhans islets in treated diabetic rats. Biochemical analysis showed that lipid fractions from total oil of Nigella sativa seeds are not hepatotoxic. However, histological study of the liver demonstrated major and minor tissue damages with the neutral fraction exhibiting the most protective effect. At the end of the experiment period (17 days) of treatment with thymoquinone (25mg/kg bw/day) or neutral lipid fraction (100mg/kg bw/day), a positive effect on the regenerative of Langerhans islets, initially distorted by STZ, was observed. Thus, the hypoglycaemic effect of neutral lipid fraction could be a result of the regeneration of the pancreatic Langerhans islets.

Oil foams stabilised solely by particles

The influence of the surface tension of the liquid (γla) on the material formed upon aerating mixtures of the liquid and fluoroethylene particles is investigated. For non-polar oils of relatively low tension, an oil dispersion of particles is formed as the liquid wets the particles. For polar liquids of relatively high tension like ethylene glycol or water which do not wet the particles, a powder-like material is formed composed of drops of the liquid coated with particles dispersed in air. However, for polar oils of intermediate tension (30–45 mN m−1) which partially wet these particles, stable air-in-oil foams can be prepared in which particles form a close-packed layer enveloping air bubbles. Using five commercial poly- or oligotetrafluoroethylene particle samples, we describe the effect of particle type, oil type and particle concentration on these foams and use freeze fracture electron microscopy to observe the arrangement of particles at the air–oil surface. Using contact angle (θ) measurements on pressed tablets of the particles, the relation between γla and θ is established: particle-stabilised oil foams form for θ between ca. 40 and 90°.

Copolymers sensitive to temperature and pH in water and in water + oil mixtures: A DSC, ITC and volumetric study

Block copolymer micelles are receiving an increasing interest because of the variety of structures and the possibilities to tune them by changing external and internal parameters achieving the desired properties for a specific purpose. We have investigated the acid/base behavior, self-assembling and solubilization ability towards polar oils of star-like copolymers named Tetronics. They are composed of branched four-arms each one consisting of two blocks made of EO and PO units linked to the diethylenediamine group, which confers pH response ability. The copolymers T1107 and T90R4 were studied with a sequential and reverse architecture. The thermodynamics of the acid/base equilibrium was studied by ITC. The aggregation of T1107 in water was analyzed as functions of pH, composition and temperature. The enhanced oil solubilization in the aqueous T1107 aggregates was widely investigated highlighting the role of the oil structure, composition, temperature and pH. As a general result, the oil induces the copolymer aggregation and the solubilization power of micelles is tunable by changing the pH. Efforts have been devoted to model the calorimetric data in order to achieve the thermodynamic properties of the involved process. Finally, we showed that the Tetronic micelles are more promising than the conventional surfactants micelles because of the larger solubilization power and flexibility of the macromolecular system.

Nanoparticle Modification by Weak Polyelectrolytes for pH-Sensitive Pickering Emulsions

The affinity of weak polyelectrolyte coated oxide particles to the oil-water interface can be controlled by the degree of dissociation and the thickness of the weak polyelectrolyte layer. Thereby the oil in water (o/w) emulsification ability of the particles can be enabled. We selected the weak polyacid poly(methacrylic acid sodium salt) and the weak polybase poly(allylamine hydrochloride) for the surface modification of oppositely charged alumina and silica colloids, respectively. The isoelectric point and the pH range of colloidal stability of both particle-polyelectrolyte composites depend on the thickness of the weak polyelectrolyte layer. The pH-dependent wettability of a weak polyelectrolyte-coated oxide surface is characterized by contact angle measurements. The o/w emulsification properties of both particles for the nonpolar oil dodecane and the more polar oil diethylphthalate are investigated by measurements of the droplet size distributions. Highly stable emulsions can be obtained when the degree of dissociation of the weak polyelectrolyte is below 80%. Here the average droplet size depends on the degree of dissociation, and a minimum can be found when 15 to 45% of the monomer units are dissociated. The thickness of the adsorbed polyelectrolyte layer strongly influences the droplet size of dodecane/water emulsion droplets but has a less pronounced impact on the diethylphthalate/water droplets. We explain the dependency of the droplet size on the emulsion pH value and the polyelectrolyte coating thickness with arguments based on the particle-wetting properties, the particle aggregation state, and the oil phase polarity. Cryo-SEM visualization shows that the regularity of the densely packed particles on the oil-water interface correlates with the degree of dissociation of the corresponding polyelectrolyte.

The Cleaning Mechanisms on Organic Grinding Fluid Applied for Si<sub>3</sub>N<sub>4</sub> Ceramic Grinding

A series of experiment were performed to test the cleaning ability of different organic emulsion for Si3N4 ceramic grinding. The experiment results showed that the grinding fluid made by short chain organic substance and alkane will induces the jam of grinding wheels. At the same time, polar organic substance with long carbon chain can suppress wheel loading phenomenon. The main reason of the jam by alkane is the nonpolar oil film surface possesses the strong attraction to abrasive dust of Si3N4, which will lead to jam in the grinding process. The polar oil film relieves the aggregation of abrasive dust in the grinding area to some extant, which is beneficial to decrease jam. By analyzing the cleaning property by some types of polar organic substances, the paper discusses the relationships of molecular structure characters to their cleaning ability.

Effect of Lipophilic Tail Architecture and Solvent Engineering on the Structure of Trehalose-Based Nonionic Surfactant Reverse Micelles

We use small-angle X-ray scattering and dynamic light scattering to investigate the structural and dynamical properties of trehalose polyisostearate, abbreviated as TQ-n (n = 3, 5, and 7), in different organic solvents, where n represents the number of isosterate chains per surfactant molecule. TQ-n spontaneously assembles into reverse micelles without addition of water at 25 °C. We found that for TQ-5 and TQ-7, steric hindrance of the lipophilic surfactant tail causes significant reduction of the aggregation number, whose scheme is clearly distinguished from the modification of the critical packing parameter. Increasing the hydrocarbon chain length of oils from octane to hexadecane favors one-dimensional micellar growth, leading to the formation of rodlike micelles due to different penetration tendencies of oils into the lipophilic shell of the surfactant. Subtle differences in solvent polarity also plays a crucial role in the micellar size, which is decreased when liquid paraffin is replaced with squalene. A further decrease is attained in more polar mixed triglyceride oils. A rising temperature also results in the same direction. The extrapolated structure factor to the zero scattering vector, S(q → 0), for the TQ-3/decane systems almost exactly follows that predicted for hard spheres, demonstrating that osmotic compressibility of the system is well explained if accounting for the excluded volume. However, we found that the effective diffusion coefficient decreases with surfactant concentration, which is an opposite trend to what is expected for hard spheres. This apparent contradiction is likely to be due to the occurrence of transient interdigitation between the lipophilic tails of neighboring reverse micelles at higher concentration. Our data highlight the relevance of the concept of "tunable reverse micellar geometry" in the novel trehalose-based nonionic surfactant binary mixtures, in which lipophilic tail architecture, solvent engineering, concentration, and temperature act as intrinsic parameters for the structure control of the reverse micelles.

The influence of base oil polarity on the tribological performance of zinc dialkyl dithiophospate additives

ZDDP blended in two base oils with different polarities were tested in mixed rolling–sliding conditions. The results showed significant differences in friction and wear when the additive is blended in the different oils. When ZDDP is blended in a non-polar base oil, the additive molecules have a better access to the steel surface, leading to higher adsorption rates than when ZDDP is blended in a polar oil, resulting in the formation of thicker ZDDP-derived reaction layers and influencing tribological performance. These results indicate the importance of base oil polarity on the ability of ZDDP to reach the surface and the influence on tribological performance.

Solubilization of dibutyltin dichloride with surfactant solutions in single and mixed oil systems

The harmful effects of organometallic compounds and their metabolites on the environment and human health require the development of more effective remediation methods. Surfactant enhanced remediation has been considered as a potential method for the removal of organometallic compounds; however, additional understanding is needed about the solubilization processes of these compounds. The surfactant enhanced solubilization of dibutyltin dichloride (DBT), an organometallic compound, was the focus of this research. In addition, the synergistic effects of DBT solubilization in perchloroethylene (PCE) and decane mixtures were evaluated. The results indicate that PCE and decane were solubilized into the core of these surfactant micelles in both single and mixed oil systems. DBT solubilization was limited when DBT alone was present (single oil system), and the nature of the solubilization isotherm suggests that DBT solubilization tended to occur near the micelle surface in a single oil system. DBT solubilization was found to increase when present in the PCE and decane oil mixture. PCE and decane may have facilitated the solubilization of DBT because they were solubilized in the micelle core. From this study, it may be concluded that the DBT behaves like polar oil such as dodecanol, having properties of a polar organic compound.

Cosmetic application of a novel technique preparing lamellar‐structure‐nano capsule with POE/POP dimethyl ether

We have developed various kinds of ultrafine emulsifying methods using POE/POP dimethyl ether. Among ultrafine emulsions made by these methods, it was reported that an o/w type emulsion, which had been prepared with POE/POP dimethyl ether, sterol surfactant, and polar oils, was characterized by a lamellar structure on the outside of nano‐size emulsified particles (lamellar nano‐capsules). The investigation of the use of various kinds of lipophilic active ingredients inside the particles showed that the particles could hold the ingredients stably. The fluidity of emulsified particles was also investigated from the measurements of fluorescent polarization and NMR measurements. On the other hand, panel tests of a cosmetic essence containing the emulsion showed that approximately 80% of panelists confirmed the essence could improve their skin condition including skin‐moisture and skin‐tension after the treatments, and they felt a clear progress in skin‐improvement by continuing use of the essence.Keywords: POE/POP dimethyl ether, sterol surfactant, polar oil, ultrafine emulsion, lamellar structure, lipophilic active ingredient, fluorescent polarization, cosmetic essence, skin‐moisture, skin‐tension

Effect of base oil polarity on micro and nanofriction behaviour of base oil + ZDDP solutions

Ball on disc tribometer and atomic force microscopy (AFM) were used to analyse the effect of base oil polarity on the friction behaviour of steel–steel contacts lubricated with base oil + zinc dialkyldithiophosphate (ZDDP) solutions. Understanding the lubrication properties of the first chemisorbed layer of additives on work pieces yields important information for the optimisation of lubricant formulation, in particular with regard to the type of additive and amount needed. To characterise the influence of base oil polarity, two reference base oils [hexadecane (non–polar) and diethylenglycol (polar)] were blended with different concentrations of C4-ZDDP, and the solutions were tested. A monolayer of base oil/additive solution was deposited on an ASI 52100 steel plate and scanned in AFM contact mode under various rubbing times and applied load conditions. An AFM technique was developed to estimate the microscopic values of friction coefficients showing how the oil polarity contributes to the differences in friction behaviour of the solution due to the addition of ZDDP. With different base oils [(hexadecane (non-polar base oil) and diethylenglycol (polar oil)] the authors observed significant different friction behaviours (in micro scale and nano scale) due to the addition of ZDDP compared to the base oil alone. This observation may be attributed to the contribution of base oil to transport the ZDDP additive onto the surface which will be discussed in more details in the paper. These results display the importance of base oil polarity on the friction behaviour of formulated lubricants containing additives.

Synthesis of silica particles with lamellar and wormhole-like bi-modal mesopores using anionic surfactant as the template

Silica particles with lamellar and wormhole-like bi-modal mesopores have been synthesized using anionic surfactant (N-lauroylsarcosine sodium) as the template. The particles with diameters of 300–500 nm possess bi-modal mesopores with pore sizes of 3 nm and 12 nm, which were ascribed to the disordered wormhole-like mesophase and lamellar mesophase, respectively. The BET surface area of the particles was 536 m2/g and the pore volume was 0.83 cm3/g. The lamellar mesophase and cylindrical mesophase were formed due to the co-assembly of the anionic surfactant and its protonized polar oil.

Effect of β-sitosterol in the antioxidative activity of oxidized lipid–amine reaction products

Abstract Phosphatidylethanolamine (PE), phosphatidylcholine (PC), lysine (Lys), and mixtures of them were tested for activity in a polar compound-stripped olive oil (SOO) and in the same oil after addition of 1500 ppm of β-sitosterol (phytosterol-added olive oil, PAO) to evaluate the role of phytosterols in the antioxidant activity of oxidized lipid–amine products. None of the added compounds protected either SOO or PAO, when tested alone at 0–400 ppm. However, mixtures of PE/Lys and PC/Lys (100/300, 200/200, and 300/100 ppm) significantly increased the induction periods of both oils. Furthermore, there was a synergism between the phospholipids and Lys, which was a consequence of the reaction between the carbonyl compounds produced in the oxidation of the phospholipid fatty acid chains and the amino group of Lys. Some of these carbonyl–amine reaction products were determined by gas chromatography–mass spectrometry after converting them into volatile derivatives. In addition, stepwise multiple regression analysis demonstrated the relationship between the induction periods and the formed products. However, the contribution of carbonyl–amine reaction products to oil stability also depended on the type of oil, therefore suggesting a role of β-sitosterol in the antioxidative activity of the compounds produced by carbonyl–amine reactions. This contribution was also confirmed by the higher synergism observed for PE/Lys and PC/Lys mixtures in PAO than in SOO.