Microporous ethylene-vinyl alcohol copolymer (EVOH) flat membranes and hollow-fiber membranes with 38 mol% ethylene content were prepared via thermally induced phase separation (TIPS) using the mixture of 1,4-buta...Microporous ethylene-vinyl alcohol copolymer (EVOH) flat membranes and hollow-fiber membranes with 38 mol% ethylene content were prepared via thermally induced phase separation (TIPS) using the mixture of 1,4-butanediol and poly(ethylene glycol)(PEG400) as diluents. Effects of the ratio of 1,4-butanediol to PEG400 on the phase diagrams, phase separation mechanism and membrane morphology were studied by small angle light scattering (SALS) measurements, differential scanning calorimetry (DSC), and scanning ele~:tron microscopy (SEM). It was found that by varying the composition of the binary solvent, the phase diagrams and membrane morphology can be controlled successfully. Moreover, the phase diagrams showed that broader regions of Liquid-Liquid (L-L) phase separation were obtained, as well as closer distances between L-L phase separation lines and Solid-Liquid (S-L) phase separation lines, Interconnected structures observed both in the flat membrane and hollow fiber membrane consist with the above results.展开更多
The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the bi-nary organic solvent diffusion method. The yield, particle size and size distribution of these nanoparticles wereeva...The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the bi-nary organic solvent diffusion method. The yield, particle size and size distribution of these nanoparticles wereevaluated. The yield of nanoparticles prepared by this method is over 90%, and the average size of the nanoparticlesis between 130-180 nm. In order to clarify the effect of the organic solvent used in the system on nanoparticle yieldand size, the cloud points of PLA and PLGA were examined by cloud point titration. The results indicate that theyields of nanoparticles increase with the increase of ethanol in the acetone solution and attain the maximum at thecloud point of ethanol, while the size of nanoparticles decreases with the increase of ethanol in the acetone solutionand attains the minimum at the cloud point of ethanol. The optimal composition ratio of binary organic solvents coin-cides to that near the cloud point and the optimal condition of binary organic solvents can be predicted.展开更多
Preferential solvation of pomalidomide(PMD)was explored in dimethyl sulfoxide(DMSO)-dimethylformamide(DMF),DMSO-tetrahydrofuran(THF),DMSO-methanol(Me OH),DMSO-isopropanol,DMSO-water,water-DMF,water-THF,water-Me OH,and...Preferential solvation of pomalidomide(PMD)was explored in dimethyl sulfoxide(DMSO)-dimethylformamide(DMF),DMSO-tetrahydrofuran(THF),DMSO-methanol(Me OH),DMSO-isopropanol,DMSO-water,water-DMF,water-THF,water-Me OH,and water–isopropanol binary mixed solvents at 298.15 K.Bosch-Rose model was utilized to determine the electronic transition energies(ET)and other preferential solvation parameters,describing solute-solute and solute-solvent interactions.We found thatλmaxsituation shifted with dielectric constant of the pure solvents meaningfully.According to the obtained results,ETenhanced andλmaxshifted to the lower wavelengths as the percentage of DMSO decreased in the binary mixtures,remarking the important role of DMSO for stabilizing the excited state(π*)of PMD chromophore via efficient intermolecular solute-solvent interactions.In addition,the aqueous binary systems showed an optimum point for the ETvalues as the percentage of water changed in the solutions.The local mole fraction of the solvents in the cybotactic region was also estimated to describe the specific and non-specific interactions in the systems.展开更多
The formation and breaking of intramolecular hydrogen bonds of bilirubin in CDCl_3-DMSO-d_6 binary solvent have been investigated by means of NMR spectroscopy.The chemical shifts of protons at dipyrrinone lactam C=O a...The formation and breaking of intramolecular hydrogen bonds of bilirubin in CDCl_3-DMSO-d_6 binary solvent have been investigated by means of NMR spectroscopy.The chemical shifts of protons at dipyrrinone lactam C=O and N-H,Pyrrole N-H,C-5,C-15 and methylene groups of 8,12-propionic acid side-chains changed markedly as a function of composition of the binary solvent.The hydrogen bond formation is dependent on the conformation of propionic acid side-chains.展开更多
This research on the solvent effects of 2-methyl-4,5-dimethoxy-3-oxo-2H-pyridizine(MDOP) in binary solvent systems on the infrared spectra for MDOP in n-hexane/CHCl3 mixture solvents showed that there were three forms...This research on the solvent effects of 2-methyl-4,5-dimethoxy-3-oxo-2H-pyridizine(MDOP) in binary solvent systems on the infrared spectra for MDOP in n-hexane/CHCl3 mixture solvents showed that there were three forms of carbonyl stretching vibration band[v(C=O)] of MPOP as mole fraction of CHCl3 in the binary solvents changes.In pure n-hexane solvent,the v(C=O) of MODP appeared at a relatively high wavenumber.With CHCl3 added,the v(C=O) shifted to lower wavenumbers.Two new bands were observed over a certain range of mixture solvent compositions.The origin of the bands was discussed in the terms of two kinds of hydrogen bond together with their individual dependence on mixture composition.COmparisons were drawn for the solvent sensitivities of v(C=O) for propanone.展开更多
Novel sorbent hydrogels containing acrylamide/sodium vinylsulfonate, carboxymethyl cellulose and zeolite were synthesized with free radical solution polymerization by using ammonium persulfate/<i><span style=...Novel sorbent hydrogels containing acrylamide/sodium vinylsulfonate, carboxymethyl cellulose and zeolite were synthesized with free radical solution polymerization by using ammonium persulfate/<i><span style="font-family:Verdana;">N</span></i><span style="font-family:Verdana;">,</span><i><span style="font-family:Verdana;">N</span></i><span style="font-family:Verdana;">,</span><i><span style="font-family:Verdana;">N’</span></i><span style="font-family:Verdana;">,</span><i><span style="font-family:Verdana;">N’</span></i><span style="font-family:Verdana;">-tetramethylethyle</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">nediamine as redox initiating pair in presence of poly(ethylene glycol) diacrylate as crosslinker. It was to investigate the water uptake properties of series of the novel hydrogels, the semi IPNs and the hybrid/biohybrid composite hydrogel sorbents synthesized in this study. Water uptake studies were performed in water and in water-solvent (acetone, methanol and tetrahydrofuran) binary mixtures at 25</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C, gravimetrically. Some swelling and diffusion parameters were calculated and discussed. It has been seen that the lower equilibrium swelling factor values in all solvent compositions in comparison with the equilibrium swelling factor values in water.</span></span></span></span>展开更多
Physical properties including refractive index, density, viscosity and conductivity for binary mixtures of 1-butyl-3-methyl imidazolium chloride([BMIM]Cl) and different organic solvents at 298.15 K have been investiga...Physical properties including refractive index, density, viscosity and conductivity for binary mixtures of 1-butyl-3-methyl imidazolium chloride([BMIM]Cl) and different organic solvents at 298.15 K have been investigated. Excess molar volumes have been calculated and obtained data has been fitted by the Redlich–Kister equation. The density and refractive index were found to increase with increasing concentration of [BMIM]Cl, however, exceptions do exist as in the case of dimethyl sulfoxide(DMSO)/[BMIM]Cl. For DMSO/[BMIM]Cl, the density decreases with increasing concentration. The addition of different organic solvents was able to disrupt the interactions within mixtures, leading to free mobility of ions. The free mobility of ions has been found to enhance conductivity and decrease viscosity to varying extents in all mixtures studied. It has been observed that solubility parameters,dielectric constants and composition of the solvents used play a vital role in determining the resultant properties.The data obtained will play an important role in understanding the effect of the addition of organic solvents in ILs to enhance their applicability.展开更多
The mineral of manganese oxalate dihydrate was synthesized in aqueous and organic-water binary solvent system (OWBS), respectively. The samples were characterized by XRD and SEM. The results show that OWBS can effecti...The mineral of manganese oxalate dihydrate was synthesized in aqueous and organic-water binary solvent system (OWBS), respectively. The samples were characterized by XRD and SEM. The results show that OWBS can effectively control the phase and morphology of manganese oxalate dihydrate. The distinction of thermal decompositon of monoclinic and orthogonal manganese oxalate dihydrate can be ascribed to the different linkage mode of manganese cation, oxalate anion and crystallized water in inter-molecules. The kinetic parameters of thermal decomposition were obtained by TG-DTA curves in various scan rates, and notably, porous manganese oxide was prepared from orthogonal manganese oxalate.展开更多
基金This work was financially supported by the Special Funds for Major State Basic Research Project (No. 2003CB615705)
文摘Microporous ethylene-vinyl alcohol copolymer (EVOH) flat membranes and hollow-fiber membranes with 38 mol% ethylene content were prepared via thermally induced phase separation (TIPS) using the mixture of 1,4-butanediol and poly(ethylene glycol)(PEG400) as diluents. Effects of the ratio of 1,4-butanediol to PEG400 on the phase diagrams, phase separation mechanism and membrane morphology were studied by small angle light scattering (SALS) measurements, differential scanning calorimetry (DSC), and scanning ele~:tron microscopy (SEM). It was found that by varying the composition of the binary solvent, the phase diagrams and membrane morphology can be controlled successfully. Moreover, the phase diagrams showed that broader regions of Liquid-Liquid (L-L) phase separation were obtained, as well as closer distances between L-L phase separation lines and Solid-Liquid (S-L) phase separation lines, Interconnected structures observed both in the flat membrane and hollow fiber membrane consist with the above results.
基金Project ( 2001AA218011) supported by the National High Technology Development "863" Program of China
文摘The nanoparticles of polylactide (PLA) and poly(lactide-co-glycolide) (PLGA) were prepared by the bi-nary organic solvent diffusion method. The yield, particle size and size distribution of these nanoparticles wereevaluated. The yield of nanoparticles prepared by this method is over 90%, and the average size of the nanoparticlesis between 130-180 nm. In order to clarify the effect of the organic solvent used in the system on nanoparticle yieldand size, the cloud points of PLA and PLGA were examined by cloud point titration. The results indicate that theyields of nanoparticles increase with the increase of ethanol in the acetone solution and attain the maximum at thecloud point of ethanol, while the size of nanoparticles decreases with the increase of ethanol in the acetone solutionand attains the minimum at the cloud point of ethanol. The optimal composition ratio of binary organic solvents coin-cides to that near the cloud point and the optimal condition of binary organic solvents can be predicted.
文摘Preferential solvation of pomalidomide(PMD)was explored in dimethyl sulfoxide(DMSO)-dimethylformamide(DMF),DMSO-tetrahydrofuran(THF),DMSO-methanol(Me OH),DMSO-isopropanol,DMSO-water,water-DMF,water-THF,water-Me OH,and water–isopropanol binary mixed solvents at 298.15 K.Bosch-Rose model was utilized to determine the electronic transition energies(ET)and other preferential solvation parameters,describing solute-solute and solute-solvent interactions.We found thatλmaxsituation shifted with dielectric constant of the pure solvents meaningfully.According to the obtained results,ETenhanced andλmaxshifted to the lower wavelengths as the percentage of DMSO decreased in the binary mixtures,remarking the important role of DMSO for stabilizing the excited state(π*)of PMD chromophore via efficient intermolecular solute-solvent interactions.In addition,the aqueous binary systems showed an optimum point for the ETvalues as the percentage of water changed in the solutions.The local mole fraction of the solvents in the cybotactic region was also estimated to describe the specific and non-specific interactions in the systems.
文摘The formation and breaking of intramolecular hydrogen bonds of bilirubin in CDCl_3-DMSO-d_6 binary solvent have been investigated by means of NMR spectroscopy.The chemical shifts of protons at dipyrrinone lactam C=O and N-H,Pyrrole N-H,C-5,C-15 and methylene groups of 8,12-propionic acid side-chains changed markedly as a function of composition of the binary solvent.The hydrogen bond formation is dependent on the conformation of propionic acid side-chains.
文摘This research on the solvent effects of 2-methyl-4,5-dimethoxy-3-oxo-2H-pyridizine(MDOP) in binary solvent systems on the infrared spectra for MDOP in n-hexane/CHCl3 mixture solvents showed that there were three forms of carbonyl stretching vibration band[v(C=O)] of MPOP as mole fraction of CHCl3 in the binary solvents changes.In pure n-hexane solvent,the v(C=O) of MODP appeared at a relatively high wavenumber.With CHCl3 added,the v(C=O) shifted to lower wavenumbers.Two new bands were observed over a certain range of mixture solvent compositions.The origin of the bands was discussed in the terms of two kinds of hydrogen bond together with their individual dependence on mixture composition.COmparisons were drawn for the solvent sensitivities of v(C=O) for propanone.
文摘Novel sorbent hydrogels containing acrylamide/sodium vinylsulfonate, carboxymethyl cellulose and zeolite were synthesized with free radical solution polymerization by using ammonium persulfate/<i><span style="font-family:Verdana;">N</span></i><span style="font-family:Verdana;">,</span><i><span style="font-family:Verdana;">N</span></i><span style="font-family:Verdana;">,</span><i><span style="font-family:Verdana;">N’</span></i><span style="font-family:Verdana;">,</span><i><span style="font-family:Verdana;">N’</span></i><span style="font-family:Verdana;">-tetramethylethyle</span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">nediamine as redox initiating pair in presence of poly(ethylene glycol) diacrylate as crosslinker. It was to investigate the water uptake properties of series of the novel hydrogels, the semi IPNs and the hybrid/biohybrid composite hydrogel sorbents synthesized in this study. Water uptake studies were performed in water and in water-solvent (acetone, methanol and tetrahydrofuran) binary mixtures at 25</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">°</span><span style="font-family:Verdana;">C, gravimetrically. Some swelling and diffusion parameters were calculated and discussed. It has been seen that the lower equilibrium swelling factor values in all solvent compositions in comparison with the equilibrium swelling factor values in water.</span></span></span></span>
基金the National Natural Science Foundation of China(51273041)
文摘Physical properties including refractive index, density, viscosity and conductivity for binary mixtures of 1-butyl-3-methyl imidazolium chloride([BMIM]Cl) and different organic solvents at 298.15 K have been investigated. Excess molar volumes have been calculated and obtained data has been fitted by the Redlich–Kister equation. The density and refractive index were found to increase with increasing concentration of [BMIM]Cl, however, exceptions do exist as in the case of dimethyl sulfoxide(DMSO)/[BMIM]Cl. For DMSO/[BMIM]Cl, the density decreases with increasing concentration. The addition of different organic solvents was able to disrupt the interactions within mixtures, leading to free mobility of ions. The free mobility of ions has been found to enhance conductivity and decrease viscosity to varying extents in all mixtures studied. It has been observed that solubility parameters,dielectric constants and composition of the solvents used play a vital role in determining the resultant properties.The data obtained will play an important role in understanding the effect of the addition of organic solvents in ILs to enhance their applicability.
文摘The mineral of manganese oxalate dihydrate was synthesized in aqueous and organic-water binary solvent system (OWBS), respectively. The samples were characterized by XRD and SEM. The results show that OWBS can effectively control the phase and morphology of manganese oxalate dihydrate. The distinction of thermal decompositon of monoclinic and orthogonal manganese oxalate dihydrate can be ascribed to the different linkage mode of manganese cation, oxalate anion and crystallized water in inter-molecules. The kinetic parameters of thermal decomposition were obtained by TG-DTA curves in various scan rates, and notably, porous manganese oxide was prepared from orthogonal manganese oxalate.