A new reactor with integrated conventional slurry stirred reactor and ceramic external membrane emulsification system, was introduced in this paper. Toluene and toluene containing surfactant was separately used as dis...A new reactor with integrated conventional slurry stirred reactor and ceramic external membrane emulsification system, was introduced in this paper. Toluene and toluene containing surfactant was separately used as dispersed phase for preparation of emulsions. Two kinds of emulsions were prepared and compared. The volume average sizes of prepared emulsions were 3.53μm and 3.6μm respectively. The results showed that the droplet sizes of two kinds of emulsions were similar, but the monodispersed emulsion was only obtained with addition of surfactant into the dispersed phase.展开更多
Oils and fats exist in many foods as emulsions, and preventing the oxidation of emulsion is vital importance for the food industry. In this study, the effect of different concentrations of Tween 20 (0.5, 2.5, 5.0, 10 ...Oils and fats exist in many foods as emulsions, and preventing the oxidation of emulsion is vital importance for the food industry. In this study, the effect of different concentrations of Tween 20 (0.5, 2.5, 5.0, 10 w% vs. oil) on the oxidation of canola oil O/W emulsion was investigated. Oxidation was conducted at 34°C in the dark and accelerated using 2,2-azobis (2,4-dimethylvaleronitrile) (AMVN) and 2,2’-azobis (2-methylpropionamidine) dihydrochloride (AAPH) as radical generators. Peroxide value (PV, mEq/kg) was monitored as generation of the primary oxidation compound. PV was suppressed by Tween 20 in a dose-dependent manner in both emulsion system using AMVN and AAPH, and the tendency of suppression was clearer in the system using AMVN than in that using AAPH. Contrarily, there were no significant differences in PV when emulsions were prepared with tocopherol-stripped oil. The particle size of emulsion droplets were also consistent among emulsions prepared. However, tocopherol contents at lipid phase of the emulsions prior to oxidation decreased with concentration of Tween 20. These results suggest that excess Tween 20 could cause tocopherol to migrate from the lipid phase of the emulsions to lipid-oil interface, suppressing the oxidation of emulsions.展开更多
Although hydrophilic membranes are desired for reducing resistance to water permeation, hydrophilic surfaces are not used in the water-in-oil(W/O) membrane emulsification process because water spreads on the hydrophil...Although hydrophilic membranes are desired for reducing resistance to water permeation, hydrophilic surfaces are not used in the water-in-oil(W/O) membrane emulsification process because water spreads on the hydrophilic surface without forming droplets. Here, we report that a hydrophilic ceramic membrane can form a hydrophobic interface in diesel at a higher temperature;interestingly, the experiments show that the contact angle increases when the temperature rises. The hydrophilic membrane surface evolves into a hydrophobic interface, particularly near the boiling point of water, resulting in a water contact angle of 147.5° ± 1.2°. This work established a method for preparing W/O monodispersed emulsions by direct emulsification of hydrophilic ceramic membranes at a temperature close to the boiling point of water.Additionally, it made high flux of membrane emulsification of monodispersed W/O emulsions possible,which satisfied the industrial requirements of fluidized catalytic cracking in the petrochemical industry.展开更多
Ultrafine γ-A12O3 particles are synthesized in Triton X- 10 0/n - hexanol/cycloh exan e/wat er water in o if(w/o )Inicroemulsion by mixing two separately prepared microemulsions containing Al(NO)3 and (Wb)ZCO, respec...Ultrafine γ-A12O3 particles are synthesized in Triton X- 10 0/n - hexanol/cycloh exan e/wat er water in o if(w/o )Inicroemulsion by mixing two separately prepared microemulsions containing Al(NO)3 and (Wb)ZCO, respectively.The ultrafine Al2O3 particles are characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD)and their size and distribution are measured. The effects of water, surfactallt and reactant concentrations on the particlesize and distribution are studied. The results show that the particle size and distribution can be changed by varying thepreparation conditions, and the size of the microemulsion droplets has a controlling effect on the size of the pafticles. A. possible mechanism of ultrafine particles (UFPs) prepared by microemulsions is proposed.展开更多
Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water (O/W) microemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., a ...Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water (O/W) microemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., a porous ceramic membrane substrate, a polyvinylidene fluoride (PVDF) ultrafiltration sub-layer, and a polyam-ide/polyvinyl alcohol (PVA) composite thin top-layer. The PVDF polymer was cast onto the tubular porous ceramic membranes with an immersion precipitation method, and the polyamide/PVA composite thin top-layer was fabricated with an interfacial polymerization method. The effects of the sub-layer composition and the recipe in the interfacial po-lymerization for fabricating the top-layer on the structure and performance of composite membranes were systematically investigated. The prepared composite membranes showed a good performance for treating the O/W microemulsions with a mean diameter of about 2.4μm. At the operating pressure of 0.4MPa, the hydraulic permeability remained steadily about 190L?m-2?h-1, the oil concentration in the permeate was less than 1.6mg·L-1, and the oil rejection coefficient was always higher than 98.5% throughout the operation from the beginning.展开更多
A novel kinetic mechanism of esterification reaction of 1-hexanoic acid with 1-butanol,catalyzed by lipase, was studied in water-in-oil microemulsions. The microemulsions were formed by alkyl polyglucoside C10G1.54/1-...A novel kinetic mechanism of esterification reaction of 1-hexanoic acid with 1-butanol,catalyzed by lipase, was studied in water-in-oil microemulsions. The microemulsions were formed by alkyl polyglucoside C10G1.54/1-butanol/cyclohexane/phosphate buffer solution. The restult shows that when the ratio of mol concentration of 1-butanol to 1-hexanoic acid is about 3.0,the initial rate V0 get the maximum values. This phenomenon was explained by the modified fishlike phase diagrams.展开更多
Uniform rice-like CdS particles were synthesized in cyclohexane/Triton X-100/n-pentanol/water quaternary microemulsions. The as-prepared samples were characterized by X-ray diffraction, transmission electron microscop...Uniform rice-like CdS particles were synthesized in cyclohexane/Triton X-100/n-pentanol/water quaternary microemulsions. The as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy, and electron diffraction. The results indicate that the size and the shape of the rice-like CdS particles can be influenced by the molar ratio of water to the surfactant(w value) and the reactant concentrations.展开更多
Spherical （Y, Gd）BO3∶Eu 3+ phosphor particles with a narrow size distribution（2～4 μm） was obtained by firing the Y-Gd-Eu-BO3 precursor prepared in a W/O style emulsion system. In the W/O emulsion system, kerose...Spherical （Y, Gd）BO3∶Eu 3+ phosphor particles with a narrow size distribution（2～4 μm） was obtained by firing the Y-Gd-Eu-BO3 precursor prepared in a W/O style emulsion system. In the W/O emulsion system, kerosene, used as oil phase, was mixed with Span 80 and Tween 80 compounds which were employed as the emulsifier with an HLB （hydrophile-lipophile balance） value of 5.2～5.3. Both rare earths （Y, Gd and Eu） nitrate and boric acid solution or ammonia solution were used as aqueous phase. The synthesis conditions, such as emulsion composition, emulsifying style, precipitation reaction process, reaction temperature, morphology control, and so on, were investigated, and the optimum synthesis conditions for preparing spherical （Y, Gd）BO3∶Eu 3+ phosphor was obtained. The phosphor was characterized by XRD, SEM, laser particle size analysis, emission and excitation spectrum under vacuum ultraviolet （VUV）, and so on. The phosphor synthesized using the water-in-oil emulsion method with median diameter （D 50 ） of 2～4 μm shows agreeable photoluminescence （PL） property and sphericity. The main emission peak appears at about 593 nm, which corresponds to 5D0→7F1 transition （magnetic-dipole transition） of the Eu 3+ ion. The cell parameters and powder diffraction data were indexed. The structure of the phosphor belongs to the hexagonal system with space group P63/m.展开更多
The flowable latent heat storage material like Oil/Water type emulsion, microencapsulated latent heat material-water mixture or ice slurry, etc., is enabled to transport the latent heat in a pipe. Supercooling phenome...The flowable latent heat storage material like Oil/Water type emulsion, microencapsulated latent heat material-water mixture or ice slurry, etc., is enabled to transport the latent heat in a pipe. Supercooling phenomenon of the dispersed latent heat storage material in continuous phase is obstructed by a latent heat storage. The latent heat storage rates of dispersed waterdrops in W/O (Water/Oil) emulsion are investigated experimentally in this study. The waterdrops in emulsion have the diameter within 3 - 25 μm, the averaged diameter of waterdrops is 7.3 μm and the standard deviation is 2.9 μm. Supercooling release of waterdrops in emulsion is examined by short time impressing of the ultrasonic. The direct contact heat exchange method is chosen as the phase change rate evaluation of waterdrops in W/O emulsion. The supercooled temperature is set as parameters of this study. The previous obtained experimental result, as the condition without impressing ultrasonic wave, showed that the 35 K or more degree from melting point brings 100% latent heat storage rate of W/O emulsion. It is clarified that it is possible to reduce 20 K of supercooling degree by impressing the ultrasonic.展开更多
The stabilizing conditions of W/O microemulsion of Tx 6～C 4H 9OH/c C 6H 12 /H 2O system were studied by visual observation. The result shows that when the weight ratio of Tx 6 to C 4H 9OH is 4∶1,the W/O microemulsio...The stabilizing conditions of W/O microemulsion of Tx 6～C 4H 9OH/c C 6H 12 /H 2O system were studied by visual observation. The result shows that when the weight ratio of Tx 6 to C 4H 9OH is 4∶1,the W/O microemulsion system has stabilizing and extensive regions, and the system is insensitive to the values of pH and in the range of room temperature.In accordance with the theoretical value of HLB,the suitable value of HLB for Tx 6 and C 4H 9OH to compose microemulsion is greater than 9,less than or equal to 10.展开更多
Poly(D,L-Lactic-Co-Glycolic Acid) (PLGA) copolymers have been extensively used as controlled-release carriers for many hydrophilic drugs because they are non-toxic, biodegradable, bioavailable, and biocompatible. In g...Poly(D,L-Lactic-Co-Glycolic Acid) (PLGA) copolymers have been extensively used as controlled-release carriers for many hydrophilic drugs because they are non-toxic, biodegradable, bioavailable, and biocompatible. In general, PLGA particles have been produced by a solvent evaporation technique utilizing water-in-oil-in-water (W/O/W) emulsions. However, W/O/W emulsions are unstable, causing the outer and inner aqueous phases to easily fuse during particle preparation. Consequently, a sufficient amount of drug was not encapsulated inside the particles. In this study, we examined a new particle preparation method utilizing a solid-in-oil-in-water (S/O/W) emulsion technique. The advantages of S/O/W emulsions, wherein a surfactant-drug complex disperses into the oil phase, were as follows: 1) leakage of hydrophilic drugs from the emulsions was inhibited, and 2) facile control over the emulsion particle size. Thus, the PLGA particles prepared by this method showed high encapsulation efficiency of drugs and formation of fine particles of submicron size by membrane emulsification were achieved.展开更多
Low-speed rotation of disc in an internal circulation of a novel de-emulsification with rotation-dise horizental contactor(RHC-D) realized de-emulsification for O/W emulsions due to repeated coalescence in oil-wet nar...Low-speed rotation of disc in an internal circulation of a novel de-emulsification with rotation-dise horizental contactor(RHC-D) realized de-emulsification for O/W emulsions due to repeated coalescence in oil-wet narrow channels at a low rotation speed. For three emulsions included ethanol/water/2-ethyl-1-hexanol, ethanol/water/2-ethyl-1-hexanol/SDS(Sodium Dodecyl Sulfonate) and 2-ethyl-1-hexanol/water/SDS emulsion, deemulsification ratios of oil phase could reach 1, 1 and 0.67 respectively at 170 r·min-1, and de-emulsification ratios increased obviously after agitating 10 min. De-emulsification experiment in the seam indicated that oil droplet sizes in O/W emulsion became larger after de-emulsification. The main de-emulsification mechanism in RHCD was the coalescence of oil droplets in oil-wet narrow channels. With increase of the rotation speed, oil droplets dispersed better in the aqueous phase. However, de-emulsification effect enhanced due to the increase of the coalescence rate at a bit higher rotation speed. In addition, internal circulation made those O/W emulsions to be broken repeatedly, consequently de-emulsification ratio increased. Repeated de-emulsification through internal circulation might make continuous extraction of ethanol come true at a low rotation speed.展开更多
A water-in-oil (W/O) microemulsion composed of Triton X-100, n-hexanol, n-hexane and water solution with hydrochloric acid was prepared. K3Fe(CN)6 was added in as a water-soluble electroactive probe, and its electroch...A water-in-oil (W/O) microemulsion composed of Triton X-100, n-hexanol, n-hexane and water solution with hydrochloric acid was prepared. K3Fe(CN)6 was added in as a water-soluble electroactive probe, and its electrochemical behavior was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is found that the H+ concentration of the water phase has a great effect on the conductivity of the W/O microemulsion, and hence influences the electrochemical behavior of K3Fe(CN)6. When the pH value of water phase is about 7, the electrical conductivity of the W/O microemulsion is only 1.2×10-6 S/cm, and K3Fe(CN)6 almost cannot react at the glassy carbon electrode. But when the H+ concentration is more than 3 mol/L, the W/O microemulsion has a good electrical conductivity and K3Fe(CN)6 shows good electrochemical performance in it. The results of CV and EIS studies indicate that the electrochemical behavior of Fe(CN)63-/Fe(CN)64- in the W/O microemulsion is different from that in the aqueous solution. This may be due to the unique liquid structure of the W/O microemulsion and the unique mass transfer in the W/O microemulsion.展开更多
Stable water-in-oil emulsions are produced in oil exploitation and cause many environmental and operational issues.In this paper,a co-polymer demulsifier is reported in detail;an emulsion polymerization method is used...Stable water-in-oil emulsions are produced in oil exploitation and cause many environmental and operational issues.In this paper,a co-polymer demulsifier is reported in detail;an emulsion polymerization method is used to prepare nano-P(MMA-AA-EA)with MMA,AA and EA as the monomers,DVB as the cross-linker and APS as the initiator.The resulting products are characterized by FT-IR.Furthermore,the surface tension and particles size analysis is investigated.The results show that the surface tension reduction is 10.66 mN/m at 20?C when the concentration of co-polymer is 1000 ppm and the average size is 76.99 nm.Moreover,the HLB of polymer is discussed specifically by changing the amount of AA.With the increase of AA,the HLB value of the polymer is increased accordingly.Besides,the demulsification performance of the co-polymer is also evaluated at different synthesis and demulsification conditions.It is showed that the maximum demulsification efficiency is 96%at 70?C for 60 min.The optimum concentration of demulsifier is 400 ppm when the amounts of AA and DVB are 1.4 g and 0.1 g,respectively.At last,the process of demulsification is showed under a microscope;the coalescence process of water droplets is indicated under the action of the demulsifier.展开更多
The rational design of emulsions requires study of the main factors that influence their formation, physicochemical properties and, consequently, stability and performance. The use of vegetable oils in the pharmaceuti...The rational design of emulsions requires study of the main factors that influence their formation, physicochemical properties and, consequently, stability and performance. The use of vegetable oils in the pharmaceutical and cosmetic industries has recently become attractive. Dipteryx alata Vogel(D. alata) is an oleaginous species native to Brazil. The seeds of this species contain highly unsaturated oil with significant amounts of tocopherols and phytosterols, representing an important source of agents capable of combatting oxidative processes. In this work, a lamellar gel phase emulsion using oil extracted from the seeds of D. alata(baru) was developed. The steps involved in the development of this research were as follows: 1) development of formulations and 2) in vitro assays by simulating the evaporation of the final product after application to the skin and Electron paramagnetic resonance spectroscopy(EPR) of fatty acid spin labels was used to investigate the profile of interaction of the dispersed systems with stratum corneum(SC) lipids. The results indicate that the developed system shows no signs of instability during the storage period. Moreover, EPR studies indicated that D. alata oil and especially the developed formulation were able to increase SC lipid fluidity and extract a fatty-acid spin label from the lipid domain structures of SC, demonstrating its potential to act as a drug or skin care vehicle.展开更多
基金the National Basic Research Program of China (No. 2003CB615700) the National Natural Science Foundation of China (No. 20125618).
文摘A new reactor with integrated conventional slurry stirred reactor and ceramic external membrane emulsification system, was introduced in this paper. Toluene and toluene containing surfactant was separately used as dispersed phase for preparation of emulsions. Two kinds of emulsions were prepared and compared. The volume average sizes of prepared emulsions were 3.53μm and 3.6μm respectively. The results showed that the droplet sizes of two kinds of emulsions were similar, but the monodispersed emulsion was only obtained with addition of surfactant into the dispersed phase.
文摘Oils and fats exist in many foods as emulsions, and preventing the oxidation of emulsion is vital importance for the food industry. In this study, the effect of different concentrations of Tween 20 (0.5, 2.5, 5.0, 10 w% vs. oil) on the oxidation of canola oil O/W emulsion was investigated. Oxidation was conducted at 34°C in the dark and accelerated using 2,2-azobis (2,4-dimethylvaleronitrile) (AMVN) and 2,2’-azobis (2-methylpropionamidine) dihydrochloride (AAPH) as radical generators. Peroxide value (PV, mEq/kg) was monitored as generation of the primary oxidation compound. PV was suppressed by Tween 20 in a dose-dependent manner in both emulsion system using AMVN and AAPH, and the tendency of suppression was clearer in the system using AMVN than in that using AAPH. Contrarily, there were no significant differences in PV when emulsions were prepared with tocopherol-stripped oil. The particle size of emulsion droplets were also consistent among emulsions prepared. However, tocopherol contents at lipid phase of the emulsions prior to oxidation decreased with concentration of Tween 20. These results suggest that excess Tween 20 could cause tocopherol to migrate from the lipid phase of the emulsions to lipid-oil interface, suppressing the oxidation of emulsions.
基金the support from the National Key Research and Development Program of China (2021YFB3801303)the National Natural Science Foundation of China (21838005, 21921006)the Key Scientific Research and Development Projects of Jiangsu Province (BE201800901)。
文摘Although hydrophilic membranes are desired for reducing resistance to water permeation, hydrophilic surfaces are not used in the water-in-oil(W/O) membrane emulsification process because water spreads on the hydrophilic surface without forming droplets. Here, we report that a hydrophilic ceramic membrane can form a hydrophobic interface in diesel at a higher temperature;interestingly, the experiments show that the contact angle increases when the temperature rises. The hydrophilic membrane surface evolves into a hydrophobic interface, particularly near the boiling point of water, resulting in a water contact angle of 147.5° ± 1.2°. This work established a method for preparing W/O monodispersed emulsions by direct emulsification of hydrophilic ceramic membranes at a temperature close to the boiling point of water.Additionally, it made high flux of membrane emulsification of monodispersed W/O emulsions possible,which satisfied the industrial requirements of fluidized catalytic cracking in the petrochemical industry.
文摘Ultrafine γ-A12O3 particles are synthesized in Triton X- 10 0/n - hexanol/cycloh exan e/wat er water in o if(w/o )Inicroemulsion by mixing two separately prepared microemulsions containing Al(NO)3 and (Wb)ZCO, respectively.The ultrafine Al2O3 particles are characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD)and their size and distribution are measured. The effects of water, surfactallt and reactant concentrations on the particlesize and distribution are studied. The results show that the particle size and distribution can be changed by varying thepreparation conditions, and the size of the microemulsion droplets has a controlling effect on the size of the pafticles. A. possible mechanism of ultrafine particles (UFPs) prepared by microemulsions is proposed.
基金Supported by the Trans-century Training Programme Foundation for the Talents by the Ministry of Education of China (No.2002-48).
文摘Fouling-resistant ceramic-supported polymer composite membranes were developed for removal of oil-in-water (O/W) microemulsions. The composite membranes were featured with an asymmetric three-layer structure, i.e., a porous ceramic membrane substrate, a polyvinylidene fluoride (PVDF) ultrafiltration sub-layer, and a polyam-ide/polyvinyl alcohol (PVA) composite thin top-layer. The PVDF polymer was cast onto the tubular porous ceramic membranes with an immersion precipitation method, and the polyamide/PVA composite thin top-layer was fabricated with an interfacial polymerization method. The effects of the sub-layer composition and the recipe in the interfacial po-lymerization for fabricating the top-layer on the structure and performance of composite membranes were systematically investigated. The prepared composite membranes showed a good performance for treating the O/W microemulsions with a mean diameter of about 2.4μm. At the operating pressure of 0.4MPa, the hydraulic permeability remained steadily about 190L?m-2?h-1, the oil concentration in the permeate was less than 1.6mg·L-1, and the oil rejection coefficient was always higher than 98.5% throughout the operation from the beginning.
文摘A novel kinetic mechanism of esterification reaction of 1-hexanoic acid with 1-butanol,catalyzed by lipase, was studied in water-in-oil microemulsions. The microemulsions were formed by alkyl polyglucoside C10G1.54/1-butanol/cyclohexane/phosphate buffer solution. The restult shows that when the ratio of mol concentration of 1-butanol to 1-hexanoic acid is about 3.0,the initial rate V0 get the maximum values. This phenomenon was explained by the modified fishlike phase diagrams.
文摘Uniform rice-like CdS particles were synthesized in cyclohexane/Triton X-100/n-pentanol/water quaternary microemulsions. The as-prepared samples were characterized by X-ray diffraction, transmission electron microscopy, and electron diffraction. The results indicate that the size and the shape of the rice-like CdS particles can be influenced by the molar ratio of water to the surfactant(w value) and the reactant concentrations.
基金Project supported by National Hi-Tech . R&D Program of China (863 Program, 2002AA302604) , MOST of China(2006CB601104) ,and Synchrotron Radiation fund of Innovation Project of Ministry of Education (20041213S)
文摘Spherical （Y, Gd）BO3∶Eu 3+ phosphor particles with a narrow size distribution（2～4 μm） was obtained by firing the Y-Gd-Eu-BO3 precursor prepared in a W/O style emulsion system. In the W/O emulsion system, kerosene, used as oil phase, was mixed with Span 80 and Tween 80 compounds which were employed as the emulsifier with an HLB （hydrophile-lipophile balance） value of 5.2～5.3. Both rare earths （Y, Gd and Eu） nitrate and boric acid solution or ammonia solution were used as aqueous phase. The synthesis conditions, such as emulsion composition, emulsifying style, precipitation reaction process, reaction temperature, morphology control, and so on, were investigated, and the optimum synthesis conditions for preparing spherical （Y, Gd）BO3∶Eu 3+ phosphor was obtained. The phosphor was characterized by XRD, SEM, laser particle size analysis, emission and excitation spectrum under vacuum ultraviolet （VUV）, and so on. The phosphor synthesized using the water-in-oil emulsion method with median diameter （D 50 ） of 2～4 μm shows agreeable photoluminescence （PL） property and sphericity. The main emission peak appears at about 593 nm, which corresponds to 5D0→7F1 transition （magnetic-dipole transition） of the Eu 3+ ion. The cell parameters and powder diffraction data were indexed. The structure of the phosphor belongs to the hexagonal system with space group P63/m.
文摘The flowable latent heat storage material like Oil/Water type emulsion, microencapsulated latent heat material-water mixture or ice slurry, etc., is enabled to transport the latent heat in a pipe. Supercooling phenomenon of the dispersed latent heat storage material in continuous phase is obstructed by a latent heat storage. The latent heat storage rates of dispersed waterdrops in W/O (Water/Oil) emulsion are investigated experimentally in this study. The waterdrops in emulsion have the diameter within 3 - 25 μm, the averaged diameter of waterdrops is 7.3 μm and the standard deviation is 2.9 μm. Supercooling release of waterdrops in emulsion is examined by short time impressing of the ultrasonic. The direct contact heat exchange method is chosen as the phase change rate evaluation of waterdrops in W/O emulsion. The supercooled temperature is set as parameters of this study. The previous obtained experimental result, as the condition without impressing ultrasonic wave, showed that the 35 K or more degree from melting point brings 100% latent heat storage rate of W/O emulsion. It is clarified that it is possible to reduce 20 K of supercooling degree by impressing the ultrasonic.
文摘The stabilizing conditions of W/O microemulsion of Tx 6～C 4H 9OH/c C 6H 12 /H 2O system were studied by visual observation. The result shows that when the weight ratio of Tx 6 to C 4H 9OH is 4∶1,the W/O microemulsion system has stabilizing and extensive regions, and the system is insensitive to the values of pH and in the range of room temperature.In accordance with the theoretical value of HLB,the suitable value of HLB for Tx 6 and C 4H 9OH to compose microemulsion is greater than 9,less than or equal to 10.
文摘Poly(D,L-Lactic-Co-Glycolic Acid) (PLGA) copolymers have been extensively used as controlled-release carriers for many hydrophilic drugs because they are non-toxic, biodegradable, bioavailable, and biocompatible. In general, PLGA particles have been produced by a solvent evaporation technique utilizing water-in-oil-in-water (W/O/W) emulsions. However, W/O/W emulsions are unstable, causing the outer and inner aqueous phases to easily fuse during particle preparation. Consequently, a sufficient amount of drug was not encapsulated inside the particles. In this study, we examined a new particle preparation method utilizing a solid-in-oil-in-water (S/O/W) emulsion technique. The advantages of S/O/W emulsions, wherein a surfactant-drug complex disperses into the oil phase, were as follows: 1) leakage of hydrophilic drugs from the emulsions was inhibited, and 2) facile control over the emulsion particle size. Thus, the PLGA particles prepared by this method showed high encapsulation efficiency of drugs and formation of fine particles of submicron size by membrane emulsification were achieved.
文摘Low-speed rotation of disc in an internal circulation of a novel de-emulsification with rotation-dise horizental contactor(RHC-D) realized de-emulsification for O/W emulsions due to repeated coalescence in oil-wet narrow channels at a low rotation speed. For three emulsions included ethanol/water/2-ethyl-1-hexanol, ethanol/water/2-ethyl-1-hexanol/SDS(Sodium Dodecyl Sulfonate) and 2-ethyl-1-hexanol/water/SDS emulsion, deemulsification ratios of oil phase could reach 1, 1 and 0.67 respectively at 170 r·min-1, and de-emulsification ratios increased obviously after agitating 10 min. De-emulsification experiment in the seam indicated that oil droplet sizes in O/W emulsion became larger after de-emulsification. The main de-emulsification mechanism in RHCD was the coalescence of oil droplets in oil-wet narrow channels. With increase of the rotation speed, oil droplets dispersed better in the aqueous phase. However, de-emulsification effect enhanced due to the increase of the coalescence rate at a bit higher rotation speed. In addition, internal circulation made those O/W emulsions to be broken repeatedly, consequently de-emulsification ratio increased. Repeated de-emulsification through internal circulation might make continuous extraction of ethanol come true at a low rotation speed.
基金Projects(20673036, J0830415) supported by the National Natural Science Foundation of ChinaProjects(05JT1026, 2007JT2013) supported by the Science Technology Project of Hunan Province, China
文摘A water-in-oil (W/O) microemulsion composed of Triton X-100, n-hexanol, n-hexane and water solution with hydrochloric acid was prepared. K3Fe(CN)6 was added in as a water-soluble electroactive probe, and its electrochemical behavior was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). It is found that the H+ concentration of the water phase has a great effect on the conductivity of the W/O microemulsion, and hence influences the electrochemical behavior of K3Fe(CN)6. When the pH value of water phase is about 7, the electrical conductivity of the W/O microemulsion is only 1.2×10-6 S/cm, and K3Fe(CN)6 almost cannot react at the glassy carbon electrode. But when the H+ concentration is more than 3 mol/L, the W/O microemulsion has a good electrical conductivity and K3Fe(CN)6 shows good electrochemical performance in it. The results of CV and EIS studies indicate that the electrochemical behavior of Fe(CN)63-/Fe(CN)64- in the W/O microemulsion is different from that in the aqueous solution. This may be due to the unique liquid structure of the W/O microemulsion and the unique mass transfer in the W/O microemulsion.
基金the Open Project Program of State Key Laboratory of Petroleum Pollution Control(Grant No.PPC2016006)CNPC Research Institute of Safety and Environmental Technology.
文摘Stable water-in-oil emulsions are produced in oil exploitation and cause many environmental and operational issues.In this paper,a co-polymer demulsifier is reported in detail;an emulsion polymerization method is used to prepare nano-P(MMA-AA-EA)with MMA,AA and EA as the monomers,DVB as the cross-linker and APS as the initiator.The resulting products are characterized by FT-IR.Furthermore,the surface tension and particles size analysis is investigated.The results show that the surface tension reduction is 10.66 mN/m at 20?C when the concentration of co-polymer is 1000 ppm and the average size is 76.99 nm.Moreover,the HLB of polymer is discussed specifically by changing the amount of AA.With the increase of AA,the HLB value of the polymer is increased accordingly.Besides,the demulsification performance of the co-polymer is also evaluated at different synthesis and demulsification conditions.It is showed that the maximum demulsification efficiency is 96%at 70?C for 60 min.The optimum concentration of demulsifier is 400 ppm when the amounts of AA and DVB are 1.4 g and 0.1 g,respectively.At last,the process of demulsification is showed under a microscope;the coalescence process of water droplets is indicated under the action of the demulsifier.
基金supported by CAPES (Coordenacao de Aperfeicoamento de Pessoal de Ensino Superior) through a student fellowship to C.S.S. Moraes
文摘The rational design of emulsions requires study of the main factors that influence their formation, physicochemical properties and, consequently, stability and performance. The use of vegetable oils in the pharmaceutical and cosmetic industries has recently become attractive. Dipteryx alata Vogel(D. alata) is an oleaginous species native to Brazil. The seeds of this species contain highly unsaturated oil with significant amounts of tocopherols and phytosterols, representing an important source of agents capable of combatting oxidative processes. In this work, a lamellar gel phase emulsion using oil extracted from the seeds of D. alata(baru) was developed. The steps involved in the development of this research were as follows: 1) development of formulations and 2) in vitro assays by simulating the evaporation of the final product after application to the skin and Electron paramagnetic resonance spectroscopy(EPR) of fatty acid spin labels was used to investigate the profile of interaction of the dispersed systems with stratum corneum(SC) lipids. The results indicate that the developed system shows no signs of instability during the storage period. Moreover, EPR studies indicated that D. alata oil and especially the developed formulation were able to increase SC lipid fluidity and extract a fatty-acid spin label from the lipid domain structures of SC, demonstrating its potential to act as a drug or skin care vehicle.
