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The conventional sol-gel method used to synthesize monodispersed spherical silica nanoparticles produces particles with irregular shapes and low monodispersity. Microreactors show a promising new platform to synthesize nanomaterials due to their unique flow and mixing characteristics. In most known shear-based droplet generation microreactors, the effect of the flowing liquid's physical properties on the reactor performance and product characteristics are not well investigated. Scaling-down the flow system was proven to change the flow behavior which will be dominated by the liquid apparent physical properties that are highly controllable. A new method to synthesize silica nanoparticles adapting the sol-gel approach in a microfluidic chip is proposed and experimentally tested in the present work. This work also analyzes changing the flowing reactants' physical properties using nonionic surfactants with different concentrations on the reaction performance and nanoparticle size and properties. A custom-made microreactor, made from polydimethylsiloxane, was designed and then fabricated using a direct writing technique. The investigated surfactant concentration was within the range of 1 to 5 vol/vol%, respective to tetraethyl orthosilicate. A traditional bench-scale sole-gel method was also performed with the same reaction properties for comparison purposes. The obtained nanoparticles were characterized using transmission electron microscopy and EDX. The silica nanoparticles synthesized from a bench-scale system showed poor monodispersity and an irregular shape compared to the perfect spherical particles produced from the microflow system. The addition of surfactant reduced the coalescence of the droplet besides reducing the size of the droplets. Increasing the surfactant concentration reduces the silica nanoparticle size. The results showed that highly monodispersed silica nanoparticles with an average size of 5.76 ± 1.27 nm were synthesized using the microflow system comparing to silica nanoparticles with a mean size of 95 ± 4 nm produced from the bench-scale. [ABSTRACT FROM AUTHOR]

This study demonstrated the possibility of separating fine beryl from quartz by using magnetic carrier technology with the presence of non-ionic surfactant (Sorbitan monooleate). Oleatecoated magnetite was used as a magnetic carrier for enhancing the magnetic properties of fine beryl to be separated and get rid of the most common associated gangue mineral "quartz". This study proved that the most important factors affecting this separation process is the pH, as the study showed that the efficiency of the separation process is the maximum possible when pH at the isoelectric point (IEP) of beryl. Where at IEP, beryl is ready to adsorb oleate-coated maginetite onto its surface and the presence of sorbitan monooleate helps this adsorption and strengthens. To demonstrate the separation process, physico-chemical surface characterization for beryl, quartz, magnetite and oleate-coated magnetite was studied before and after treatment with sorbitan monooleate using zeta potential measurements and Fourier Transform Infrared (FTIR). Mineralogical characterization was take place for separated minerals of beryl, quartz and magnetite using x-ray diffraction (XRD) analyses and scanning electron microscope (SEM) with energy-dispersive spectrometer (EDS) unit. The magnetic carrier separation tests were performed in this study in the case of separate minerals investigated that fine beryl (94% recovery) could be recovered under optimum test conditions of 2.5 pH, 4.29 g/L sorbitan monooleate and 1:0.5 beryl to oleate-coated magnetite ratio, while quartz under the same conditions was recovered by 9.8%. FTIR measurements for the investigated minerals before and after treatment with sorbitan monooleate confirmed that the adsorption of sorbitan monooleate on the surface of beryl far exceeds that of the surface of quartz at beryl IEP. [ABSTRACT FROM AUTHOR]

Waterborne polyurethanes (WPUs) have recently attracted enormous attentions in extensive industrial applications because of their sustainability and low toxicity. However, due to the use of water as the dispersion medium and abundant hydrophilic moieties of the molecular skeleton, waterborne polyurethanes always suffer from poor mechanical properties and inferior water resistance. In this work, dehydrated sorbitan monooleate (SP), a bio-derived renewable polyol, is introduced into the waterborne polyurethane skeleton to modulate the contents of the traditional trifunctional polyol of trimethylolpropane (TMP). Due to the rigid furan ring and the fatty side chain in the SP, the SP-modulated waterborne polyurethanes (WPU-SP) exhibit simultaneous excellent mechanical properties, high toughness, flexibility, and versatility, with the maximum tensile strength of WPU-SP reaching 39.19 MPa, and the film is capable of lifting weights over 25,000 times its own weight without fracture. Additionally, compared to the traditional waterborne polyurethane extended with TMP, the wear resistance and the water resistance of WPU-SP are significantly improved, as the decreases in wear rate and water absorption rate of WPU-SP are up to 59 % and 45 %, respectively. Benefiting from these unique properties, the WPU-SP shows excellent performance in anticorrosion and exceptional applicability for soft leather materials, in which the corrosion prevention efficiency can reach over 95 % and the wear index can be reduced to within 10 mg as a protective coating. This study represents a facile and effective approach for developing high-performance sustainable waterborne polyurethane materials through the incorporation of SP into polymer networks. [Display omitted] • Bio-based waterborne polyurethane (WPU-SP) obtained by introducing dehydrated sorbitan monooleate (SP). • WPU-SP exhibit excellent mechanical properties, high toughness, flexibility, and versatility • Wear resistance and water resistance of WPU-SP are significantly improved. • WPU-SP shows excellent anti-corrosion performance. [ABSTRACT FROM AUTHOR]

The performance of the mixed anionic (sodium oleate) / nonionic (sorbitan monooleate) collectors on fergusonite flotation and separation from silicate gangue minerals was investigated using the flotation tests. The surface characterization of fergusonite before and after the treatment with the mixed collectors was determined using the zeta-potential measurements and FT-IR analyses. The results obtained from this study showed that the flotation recovery of fergusonite using sodium oleate enhanced in the presence of sorbitan monooleate, and the optimum floatability was achieved at pH 5 using 1 Kg/Mg blended collectors of sodium oleate and sorbitan monooleate as by a ratio 1:1 and methyl isobutyl carbinol (MIBC) as a frother. It was also found that the addition of sodium metasilicate to citric acid as a depressant showed a high affinity for silicate gangue minerals and weak affinity for fergusonite. The zeta-potential and FT-IR measurements of fergusonite after the treatment with the mixed collectors indicated a strong adsorption of these molecules on the particle surface due to chemisorptions. Additionally, The SEM analysis of high grade froth and its corresponding tailing product showed that the fergusonite mineral mostly concentrated in the froth, while the gangue silicate minerals relatively concentrated in the tailing. Finally, synergistic interaction between the anionic and nonionic surfactants was observed during adsorption on fergusonite and was succeeded for separation from its gangue silicate minerals. [ABSTRACT FROM AUTHOR]

The effects of a typical anti-agglomerant, sorbitan monooleate (Span80), on the interactions between cyclopentane (CyC5) hydrate particles and water droplets were investigated using a micromechanical force (MMF) apparatus. The concentration of Span80 in CyC5 was ranged from 0.01 wt% to 1 wt%, and the experimental temperature was set at 1.5°C and 7°C, respectively. The results indicate that the absorption of Span80 on the droplet surface can render the interfaces more stable, preventing hydrate agglomeration. When the preload/contact force exceeds the strength of the interface (< ∼ 10 µN), the droplet ruptures, and the subcooling influences the interaction behavior significantly. At the lower temperature (1.5°C), the water droplet can spontaneously spread over the whole hydrate particle due to the significant reduction in water–CyC5 interfacial tension, and the water converts into hydrate rapidly. In this case, Span80 actually accelerates the agglomeration process and grants much shorter time to allow the external force to separate the water droplet and hydrate particle. At the higher temperature (7°C), the capillary bridge dominates the interaction behavior. The addition of Span80 reduced the capillary force through reducing the water–CyC5 interfacial tension. The measurements and observations in the present work can provide new insights into the mechanism of Span80 on inhibiting hydrate agglomeration. [ABSTRACT FROM PUBLISHER]

Measurements by capillary pressure tensiometry, under microgravity conditions aboard the International Space Station, supplied a consistent set of reliable results for the dynamic interfacial tension and for the interfacial dilational viscoelastic modulus, quantitatively characterizing the dynamics of Span-80 adsorbed layers at the paraffin-oil/water interface. The experiments were executed at three different temperatures, i.e., 20, 30 and 40 °C, according to a pre-established built-in time-line in the orbiting facility. The interfacial area was subjected to perturbations with various functional forms (square pulses, ramps and harmonic oscillations), at three consecutive amplitudes (5%, 10% and 20%). Each experiment was performed in three successive repetitions, in view of an advantageous telemetered data redundancy. The interfacial responses to imposed perturbations, for the studied minimal surfactant concentration of Span-80 in paraffin-oil (that is (2 ÷ 3) × 10 −5 mol/dm 3 ) revealed a diffusion-controlled adsorption mechanism, definitely matching the Lucassen & Van den Tempel model in the frequency-domain representation. The interfacial responses also showed a linearity range up to the 20% amplitude. Interfacial relaxation responses to transient interfacial perturbations substantially validated the diffusion-controlled model for the adsorption mechanism, in the time-domain representation. [ABSTRACT FROM AUTHOR]

In this paper, based on the optimized formulation of olanzapine (OLN) transdermal patch, the role of sorbitan monooleate (SP) in OLN release and percutaneous absorption processes was probed in vitro and in vivo . Rheological test, DSC, FT-IR and molecular modeling were conducted to elucidate the effect of SP on the release process of OLN from transdermal patch. Additionally, the action of SP on the percutaneous absorption process was probed using tape stripping transdermal experiment, confocal laser scanning microscopy (CLSM), ATR-FTIR and molecular docking. The results showed that the hydrogen bonding interaction between OLN and pressure sensitive adhesive (PSA) was weakened by SP, which resulted in a decrease in the cohesive interaction between polymer chains and an increase in the formation of free volume of PSA, thus, the release of OLN from patch was promoted. Meanwhile, the O H groups of SP interacted with the polar head groups of the ceramides, which increased the fluidity of the skin lipids, thereby improved the ability of OLN percutaneous absorption. In summary, this study demonstrated that not only the release but also the percutaneous absorption processes were promoted by SP. This study provided comprehensive molecular level understanding on the effect of penetration enhancer on transdermal patch and strategies for rationally selection of chemical enhancer for transdermal drug delivery systems. [ABSTRACT FROM AUTHOR]

To improve the lower contrast ratio of yellow-white dual color electrophoretic display cell, dispersion polymerization, and miniemulsion polymerization method were used to obtain good performance of Pigment Yellow 110 (PY110) composite particles. Crude PY110 particles and Span80 were suspended into the ethanol by dispersion method to obtain PY110-S, which were subsequently coated with styrene (St) through a mini-emulsion polymerization procedure to acquire PS/PY110-S as an electronic ink material. The modified pigments were characterized by Fourier transform infrared spectroscopy (FTIR), Scanning electron microscope (SEM), UV–vis spectroscopy. Furthermore, the Pigment Red 146 which coated with styrene (St) through a miniemulsion polymerization procedure was doped into the PS/PY110-S. Then, the obtained mixed particles were successfully incorporated in an electrophoretic display cell. And the contrast ratio of yellow-white electrophoretic display cell was significantly improved. The contrast ratio reached 1.58. [ABSTRACT FROM PUBLISHER]

Innovative approaches in nanotechnology can provide drug delivery systems with a high potential in different fields. To avoid trial and error assays as a main driving force governing new designs and, furthermore, to develop successful nanosystem optimization strategies, it is of the greatest importance to develop specific characterisation techniques beyond conventional determinations of size, zeta potential and morphology. However, the application of techniques able to determine some key characteristics, such as nanostructure (i.e., solid structure vs vesicular), and the way in which the reorganization of components takes place on these structures has been scarcely explored. The present work has been devoted to provide some insights about the potential offered by some NMR techniques to those scientists working on nanotechnological approaches. For this purpose, we selected our nanosystems based on sorbitan monooleate as a case study. We used 1 H NMR methods, including a recently proposed method relying in the well-known Saturation Transfer Difference (STD) experiment for the observation of ‘invisible signals’ in large aggregates (Invisible State STD or ISSTD). Overall, these techniques revealed the presence in these nanosystems of a gradient of flexibility from an internal rigid core towards a more flexible region located on their surface, as well as the absence of water content in both regions. Such structure, corresponding to a solid nanostructure rather than a vesicular one, can explain some of the interesting properties previously observed for these innovative nanosystems, such as their high stability, and allows us to refer to these nanosystems with the term “Solid Sorbitan esters Nanoparticles” (SSN). On the basis of the valuable information provided by the mentioned characterisation techniques, it is our understanding that they could facilitate the future design of new drug delivery nanosystems as well as the improvement of existing ones and/or the development of new applications for classical drug delivery concepts. [ABSTRACT FROM AUTHOR]

Barium titanate, BaTiO 3 , nanoparticles (NPs) have been widely used as a ferroelectric/piezoelectric/ pyroelectric material in the electronic-optical ceramic industry. However, the stability of BaTiO 3 NP suspension is a matter of concern for their advanced applications in wet-ceramic manufacturing, imaging, and electrorheological fluids. In this study, we investigated the effect of three different surfactants (sodium dodecylbenzenesulfonate (anionic), cetyltrimethylammonium bromide (cationic), and sorbitan monooleate (non-ionic)) on the stability of PEGylated BaTiO 3 nanoparticles in two solvents (water and ethylene glycol) by means of dynamic light scattering, ζ potential, UV–visible spectroscopy, scanning electron microscopy, and visual observation. Our findings indicate that the anionic surfactant acted as the best stabilizer for BaTiO 3 nanofluids, while the cationic surfactant was the least favorable stabilizer in both water and ethylene glycol, due to the balance between attraction and repulsive forces. The results of this research provide a simple and effective approach to control and improve the colloidal stability of BaTiO 3 nanoparticles. [ABSTRACT FROM AUTHOR]

A stable emulsion with NaOH as the inner phase, sorbitan monooleate (span80) as the surfactant, and kerosene, cyclohexane, n-heptane, methylbenzene or p-xylene as the organic membrane phase, was prepared successfully by a magnetic stirring apparatus at low stirring speed (720rev min−1) to make the pre-emulsion and then using the ultra-sonication devices. The separation efficiency in emulsion liquid membrane system to remove 1-naphthol was investigated. The parameters that affect the removal efficiency of 1-naphthol were studied systematically. At the optimal conditions, cyclohexane as the solvent phase, 2% NaOH as the inner phase, ultrasound time 5 minutes, the ratio of oil to inner phase 1:2, pH of feed phase without adjusted (pH = 6·4), contact time 15 minutes, ratio of emulsion to water 1:5, 1-naphthol removal can nearly reach 98% with a low level of 1·14% of emulsion leakage at 20 minutes. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bio-based WPU with excellent mechanical and thermo-physical properties were prepared. • The bio-based WPU films could lift heavy objects 10,330 times their own weight. • These WPU coatings demonstrated effectively anticorrosive effect. • The resulting WPU coatings exhibited excellent UV resistance in outdoor practical application tests. Sorbitan monooleate (SP) is considered to be a promising renewable polyol with unique molecular structures for the development and design of bio-based waterborne polyurethane (WPU) with versatility and excellent mechanical properties. In this study, SP was used as a bio-based polyol in combination with castor oil to design and prepare a series of bio-based WPU with anti-ultraviolet, corrosion resistance and excellent mechanical properties. The influence of the hydroxyl ratios between SP and castor oil on the chemical structures and properties of bio-based WPU dispersions and the resulting WPU films was systematically studied. The resulting WPU films exhibited excellent mechanical properties and thermo-physical properties due to the presence of large amounts of hydrogen bonding and rigid furan ring, and high crosslinking densities. The bio-based WPU films could lift heavy objects 10,330 times their own weight. The resulting WPU coatings could resist ultraviolet radiation in the region (200–400 nm) and exhibited excellent UV resistance in outdoor practical application tests. In addition, these WPU coatings demonstrated effectively anticorrosive effect in which the anticorrosion period of the coating on the tinplate outdoors could be as long as 6 months in terms of corrosion potential, corrosion current and corrosion protection efficiency of the coating reached −0.507 V, 2.92 × 10−6 A, and 95.39%, respectively. This study provides a new and simple method for preparing bio-based WPU with excellent anti-ultraviolet performance, anti-corrosion performance and excellent mechanical properties. [ABSTRACT FROM AUTHOR]

In this study, sorbitan monooleate was used to pretreat lignite prior to flotation tests. First, the lignite sample and water were mixed with 0%, 0.5%, 1%, 1.5% and 2% (on the basis of the weight of the coal) of sorbitan monooleate to produce five types of flotation slurries. FTIR, XPS and SEM were used to analyze the surface properties of the lignite sample. The flotation tests were used to indicate the improvements in flotation of lignite after the sorbitan monooleate pre-treatment. FTIR and XPS results showed that there are many oxygenated functional groups in lignite such as carboxyl group and hydroxyl groups. Furthermore, SEM results showed that there are many holes on the lignite surface. These holes will be filled with water in the flotation pulp. The flotation results indicated that sorbitan monooleate can improve the lignite flotation at low concentrations of sorbitan monooleate. However, the flotation behavior of lignite deteriorated at higher concentrations of sorbitan monooleate. [ABSTRACT FROM AUTHOR]

Highlights: [•] Novel amphiphilic gellan co-polysaccharide was synthesized and characterized. [•] Co-polysaccharide formed stable, spherical nanomicellar structures in water. [•] Nanomicelles incorporated >95% budesonide in their lipophilic core. [•] Maximum 50% drug released into simulated nasal fluid (pH 5.5) in 6h. [•] Micellar solution of budesonide could avoid adverse events of anti-rhinitis. [Copyright &y& Elsevier]

The crystallization behavior of cocoa butter (CB) is the essential structuration issue in the development of chocolate products. An alternative to modify and control the crystallization patterns of CB in chocolate production is the incorporation of specific emulsifiers in their formulations. In this work, the effects of sorbitan monostearate (SMS) and sorbitan monooleate (SMO) in the crystallization and consistency behaviors as well as on the microstructure of CB were evaluated. CB samples at three different concentrations (0.5, 1.0 and 1.5 % w/w) of SMS and SMO were prepared and their main physical-chemical attributes determined. CB added with 1.5 % of SMS showed the largest effects with a sharp increase in the onset of the crystallization temperature (from 19.3 to 23.8 °C) and doubling the yield value (consistency) of pure cocoa butter. The classic two-step isothermal crystallization behavior and morphology of CB were also modified with the addition of SMS. A possible explanation based on the solubility of SMS in an organic medium and its ability of self-assembling was suggested as a mechanism for SMS performance in CB. SMS was considered as a potential crystal modifier for CB by changing its crystal structure and enhancing its thermal resistance-factors that favor the use of this emulsifier in the production of improved thermally stable chocolates. [ABSTRACT FROM AUTHOR]

Abstract: Although the stability of emulsions is widely discussed in the literature, most of them dealt with oil-in-water emulsions or water-in-oil systems with solid and semi-solid structures, which are easier to stabilize. In this study, the stability mechanism of liquid water-in-oil emulsions was investigated in different systems. The combination of two different oils (soybean oil and hexadecane) and three emulsifiers (PGPR, Span 80 and lecithin) at two water:oil ratios was investigated. Emulsions with higher kinetic stability – water and soybean oil emulsion stabilized with PGPR and water and hexadecane with Span 80 – presented an interface with low initial interfacial tension and practically constant complex viscoelastic modulus with time. Therefore, small droplets were formed and their coalescence was hindered by a stable elastic interface. The molecular structure of both oil and emulsifier were important to define the emulsion stability. Better chemical affinity of the hydrophobic moieties of the emulsifier and the oil led to more stable interface. Steric stability was obtained in more viscous systems, such as those at higher water volume fraction content. However, the water incorporation capacity into the emulsion depended on the molecular structure of hydrophilic portion of the emulsifier. Moreover, the water – soybean oil systems with Span 80 or lecithin emulsifiers did not form a macroemulsion, but a gelled structure. This study discussed the many factors that affect the emulsion formation and stability, which can contribute to the development of new water-in-oil emulsion based products with higher stability. [Copyright &y& Elsevier]

Aim and scope. The purpose of this study was to determine the effects of 2 different concentrations of sorbitan monooleate and methylated spirit as surfactants in the electromotive administration of diclofenac diethylamine among participants with knee osteoarthritis (OA). Materials and methods: Fifteen participants with knee OA were randomly allocated into 3 groups. Prior to diclofenac diethylamine iontophoresis, participants in group 1 had the stimulation electrode pads soaked in 1% w/v sorbitan monooleate and same procedures were adopted for those in group 2 and 3 but soaking and cleansing were in 0.5% w/v sorbitan monooleate and methylated spirit surfactants respectively. The data were analyzed using descriptive and inferential statistics. Results. There was significant reduction in pain intensity immediately after the first treatment session within group 1, (p< 0.02) and group 3, (p<0.05) but there was no significant difference in pain intensities of the subjects who received 0.5% sorbitan monooleate (group 2). Also, there was significant increase in knee flexion of group 1 participants after the first treatment session (p< 0.006). At 4th week, there was no significant difference in pain intensity and active knee flexion ROMs across the groups. Conclusion. The study concluded that there was no difference in the cumulative effects of 1%, 0.5%w/v sorbitan monooleate concentrations and methylated spirit as surfactants at the end of 4 weeks. However, 1% w/v of sorbitan monooleate concentration and methylated spirit enhanced reduction in pain intensity and increase in knee flexion at first treatment session. [ABSTRACT FROM AUTHOR]

The water-based materials for mine gas absorption and explosion suppression were prepared, in which the mixed organic aggregate of Span80 and alkaline salt can be used as methane absorbent. Methane was used as a model of mine gas, and the absorptions of methane with different complex materials were studied using head space gas chromatography. Then the state of aqueous material was characterized with laser light scattering instrument and the effects of different complex materials on explosion suppression were preliminarily studied in explosion chamber which can simulate mine gas explosion. The research results showed that complex material could absorb methane and there was some correlation between the mean diameter of organic aggregate in aqueous material and the absorption effect. Additionally, the aqueous material could suppress the methane explosion to some degree. The material can absorb mine gas in atomization condition, therefore, degrease mine gas concentration and influence the distribution of mine gas in the space, and then suppress the mine gas explosion to some extent. [ABSTRACT FROM AUTHOR]

[Display omitted] • Needle-like γ-Al 2 O 3 nanoparticles and SMO was successfully used as CFI additives. • The addition of γ -Al 2 O 3 nanoparticles and SMO reduces of crystallization temperature. • CFI additives were able to prohibit thermodynamic spontaneity of wax crystallization. • DLVO analysis showed that γ -Al 2 O 3 nanoparticles had high colloidal stability in fuel. • CFI additives were able to suppress the insoluble paraffinic "house of cards" crystals. This paper reports a thermodynamic investigation on the role of γ-Al 2 O 3 nanoparticles and sorbitan monooleate (SMO) as cold-flow improver additives for B30 biodiesel blend. Here, the two additives were able to improve fuel's cold-flow properties and responsible for reducing wax crystallization temperature as low as 6.42 °C. Based on DCS analysis, the addition of individual SMO or γ-Al 2 O 3 nanoparticles gave rise to the increase in crystallization enthalpy and entropy. However, the opposite effect was observed when they were used in combination. This synergistic effect was found to be responsible for making them effective in the prohibiting the spontaneity of wax crystallization, which was proven by the increase in crystallization Gibbs free energy (Δ G xtal) value from −72.9 to −35.7 J/g. This is primarily due to that the ability of SMO to stabilize wax nuclei and the role of γ-Al 2 O 3 nanoparticles as an additional nucleation site. Furthermore, DLVO analysis also revealed that γ-Al 2 O 3 nanoparticles exhibited high colloidal stability, enabling them to facilitate stable Pickering emulsion formation. Finally, microscopic observations demonstrated that both additives could suppress the formation of insoluble paraffinic "house of cards" crystals. [ABSTRACT FROM AUTHOR]

The molecular compositions of the commercial nonionic surfactants Span 80 and Span 85 were analyzed by reversed phase high performance liquid chromatography (HPLC). Both surfactants are mixtures of fatty acid esters, containing monoesters, diesters, triesters, and tetraesters. While diesters dominate in the case of Span 80, Span 85 contains mainly tetraesters. Vesicles were prepared from Span 80 (or Span 85) by a two‐step emulsification method that involved homogenization and separation steps in which a portion of the surfactants was removed. The composition of the vesicles was analyzed by HPLC with respect to the different esters present. Although commercial Span 80 and Span 85 differ considerably in their molecular compositions, the ester profiles of the vesicles formed were in both cases rather similar and dominated by diesters. Therefore, the particular vesicle preparation method leads to a molecular selection of mainly those components that are prone to form bilayers. [ABSTRACT FROM AUTHOR]

Abstract: This study reports the laboratory optimization for the preparation of sustained release amoxicillin (AMX) ethylcellulose microcapsules by an emulsion solvent evaporation process by adjusting the viscosity and concentration of ethylcellulose, ratio of amoxicillin to ethylcellulose, and concentration of emulsifier and pore inducer. When ethylcellulose with a viscosity of 45 mPa·s was used, almost no material stuck to the inside wall of the beaker and uniform microcapsules were prepared. The average diameter of microcapsules increased and yield and release rate decreased as the concentration of ethylcellulose increased from 1% to 8%. The release of amoxicillin from microcapsules was influenced by the ratio of the weight of drug to that of ethylcellulose and ratios of 2:1 and 4:1 were most suited for optimum amoxicillin release. The average diameter of microcapsules decreased and the release rate increased as the concentration of the emulsifier increased from 1.5% to 6.0%, however, the size distribution became significantly wider with the increase in the concentration of sorbitan monooleate. Addition of small amounts of a water-soluble agent sucrose improved the release of active ingredient from the microcapsule matrix without influencing the morphology and particulate properties of the microcapsules. [Copyright &y& Elsevier]

Abstract: Surfactant-enhanced in situ flushing was performed to remediate soil and groundwater at a diesel contaminated area, which had been used as a military vehicle repair area in Korea for 45 years. A pilot-scale site (4m×4m×4m) was selected within the contaminated area for in situ flushing; the selected site was composed of heterogeneous sandy and silt-sandy soils, with an average hydraulic conductivity (K) of 2.0×10−4 cm/s. Two percent of sorbitan monooleate (POE 20) was mixed with uncontaminated groundwater and five pore volumes of solution (three pore volumes of surfactant solution and two pore volumes of groundwater alone) were flushed to remove diesel from the site. The effluent TPH (total petroleum hydrocarbon) concentration with surfactant solution flushing increased to 1761mg/L, which was over 200 times higher than the average concentration with only groundwater flushing. A total of 48kg of TPH (about 88% of the initial TPH) was removed from the pilot site with five pore volumes of 2% sorbitan monooleate solution flushing; this total was more than 75 times the amount that was removed when flushing with water alone (less than 640g). All of the extracted solution was treated by means of a chemical treatment process, which included the use of a dissolved air flotation system to lower the concentration of solution below 5mg/L and the treated solution was then disposed of in a nearby sewage drain. [Copyright &y& Elsevier]

This paper is devoted the synthesis of poly(sodium acrylate) by an inverse-suspension polymerization technique. Ammonium persulfate, ethylcellulose and toluene were used as initiator, suspending agent, and continuous organic phase, respectively. Two surfactants, sorbitan monooleate (SMO) and sorbitan monostearate, were used as the suspension stabilizers. The effect of the initiator concentration as well as the type and concentration of the surfactant on the polymer molecular weight and solution viscosity was investigated. Participation of the unsaturated surfactant (SMO) in the free radical polymerization was recognized to be the main reason of enhancement of the average molecular weight and viscosity of the products. A similar effect was observed when the polymerization reactions were run in the presence of air. In the latter conditions, however, an inhibition effect of atmospheric oxygen resulted in substantially decreased solution viscosity. Meanwhile, it was found that higher polymers were obtained when the as-synthesized beads were dewatered and hardened in methanol rather than in acetone. [Copyright &y& Elsevier]

Creams from three components, surfactant, purified water and oil, were prepared. Comparable molar fractions of components were used in order to better understand the structural properties of the components used. The surfactants were sorbitan monoesters, sorbitan monolaurate, monopalmitate, monostearate and monooleate, which differed from each other in the length or structure of the hydrocarbon chain. The oils used were isopropylpalmitate and myristate, and they differed from each other in the length of the fatty acid chain. Rheological properties, droplet size distributions and types (either o/w or w/o) of the creams were studied. The rheological tests used were oscillation stress sweep test, creep recovery test and viscosity test. The modelling of the creep phase was based on the creep recovery test. Sorbitan monolaurate and monostearate formed w/o creams, sorbitan monopalmitate and monooleate o/w creams. It appeared that the double-bonded structure of the surfactant made the cream less elastic. Elasticity was increased due to lenghtening of the alkyl chain of the surfactant and increased amount of surfactant. Also the lenghtening of the fatty acid chain of the oil made the creams more elastic. The results of the rheological tests and droplet size distributions correlated well each other. According to the modelling of the creep phase, creams could be represented either with the Burger model or with the Maxwell model. [Copyright &y& Elsevier]