Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UH...Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UHMWPE. Small angle laser light scattering (SALLS) and differential scanning calorimetry (DSC) were used to determine the phase separation temperatures,i.e.the cloud points and the dynamic crystallization temperatures,respectively.It was found that the cloudI points were coincident with the cryst...展开更多
Ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6)as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF)membranes via thermally induced phase s...Ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6)as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF)membranes via thermally induced phase separation(TIPS).Phase diagram of PVDF/[BMIM]PF6 was measured.The effects of polymer concentration and quenching temperature on the morphologies,properties,and performances of the PVDF membranes were investigated.When the polymer concentration was 15 wt%,the pure water flux of the fabricated membrane was up to nearly 2000 L·m-2·h-1,along with adequate mechanical strength.With the increasing of PVDF concentration and quenching temperature,mean pore size and water permeability of the membrane decreased.SEM results showed that PVDF membranes manufactured by ionic liquid(BMIm PF6)presented spherulite structure.And the PVDF membranes were represented asβphase by XRD and FTIR characterization.It provides a new way to prepare PVDF membranes with piezoelectric properties.展开更多
High density polyethylene (HDPE)/polyethylene-block-poly(ethylene glycol) (PE-b-PEG) blend porous membranes were prepared via thermally induced phase separation (TIPS) process using diphenyl ether (DPE) as d...High density polyethylene (HDPE)/polyethylene-block-poly(ethylene glycol) (PE-b-PEG) blend porous membranes were prepared via thermally induced phase separation (TIPS) process using diphenyl ether (DPE) as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry (DSC). By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD). The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS). Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.展开更多
Poly(vinylidene fluoride) /polysulfone(PVDF/PSF) flat blend membrane was prepared via thermally induced phase separation(TIPS) technique.The membrane formation mechanism and membrane structure were investigated and th...Poly(vinylidene fluoride) /polysulfone(PVDF/PSF) flat blend membrane was prepared via thermally induced phase separation(TIPS) technique.The membrane formation mechanism and membrane structure were investigated and the effects of PSF/PVDF weight ratio on morphology,crystallinity,porosity,and mechanical properties of the membrane were discussed.The relationship between membrane structure and performances,such as pure water flux and the rejection of carbonic black,was also discussed.It was found that solid-liquid(S-L) phase separation occurred for the PVDF/PSF/diluent system.The addition of PSF influences structure and crystallinity of the membrane,which in turn influences mechanical properties and performances of the membrane.The results reveal that it is possible to obtain network structure via S-L phase separation by blending the polymer,which has a partial compatibility with PVDF.展开更多
A review of recent research related to micro- porous polymeric membranes formed via thermally induced phase separation (TIPS) and the morphologies of these membranes is presented. A summary of polymers and suitable ...A review of recent research related to micro- porous polymeric membranes formed via thermally induced phase separation (TIPS) and the morphologies of these membranes is presented. A summary of polymers and suitable diluents that can be used to prepare these microporous membranes via TIPS are summarized. The effects of different kinds of polymer materials, diluent types, cooling conditions, extractants and additive agents on the morphology and performance of TIPS membranes are also discussed. Finally new developments in TIPS technology are summarized.展开更多
A non-toxic and environmentally safe diluent,acetyl tributyl citrate,was employed to prepare poly(vinylidene fluoride)-co-hexafluoropropylene membranes via thermally induced phase separation.Effects of the polymer con...A non-toxic and environmentally safe diluent,acetyl tributyl citrate,was employed to prepare poly(vinylidene fluoride)-co-hexafluoropropylene membranes via thermally induced phase separation.Effects of the polymer concentration on the phase diagram,membrane morphology,hydrophobicity,pore size,porosity and mechanical properties(tensile stress and elongation at break)were investigated.The results showed that the pore size and porosity tended to decrease with increasing polymer concentration,whereas the contact angle,liquid entry pressure and mechanical properties showed the opposite trend.In direct contact membrane distillation operation with 3.5 wt-%sodium chloride solution as the feed solution,the prepared membranes performed high salt rejection(>99.9%).Furthermore,the prepared membranes retained excellent performance in long-term stability tests regarding the permeate flux and salt rejection. ne distillation.展开更多
The asymmetric polyamide-6 (PA6) membranes were prepared by thermally induced phase separation. From the scanning electron microscopy (SEM) images, it is observed that with the increase of silicon dioxide (SiO2)...The asymmetric polyamide-6 (PA6) membranes were prepared by thermally induced phase separation. From the scanning electron microscopy (SEM) images, it is observed that with the increase of silicon dioxide (SiO2) content the structure of obtained membranes gradually varied from cellular structure to large ball-shaped cluster aggregates. Subsequently, with the addition of SiO2, pure water flux increased first and then decreased, while rejection showed the opposite trend. Besides, raising the coagulation bath temperature was favorable to increase pure water flux. Consequently, different membrane morphologies and performance were obtained by changing SiO2 content and coagulation bath temperature.展开更多
The effect of a N,N-dimethylformamide(DMF)/acetone solvent system(3:7,4:6,5:5,6:4,7:3)and spinning medium(air and water)on the membrane morphology and the structure-property relationship were investigated.A facile met...The effect of a N,N-dimethylformamide(DMF)/acetone solvent system(3:7,4:6,5:5,6:4,7:3)and spinning medium(air and water)on the membrane morphology and the structure-property relationship were investigated.A facile method was optimized to generate a porous,polymer-fiber membrane via the combinative effect of electrospinning and thermally inducing phase separation of the DMF/acetone(4:6)solvent system in a water medium.The attenuated total reflection(ATR)-Fourier transform infrared(FTIR)results showed an increased b-phase compared to the pristine poly(vinylidene fluoride)(PVDF).The XRD and DSC results further confirmed that the co-existing a-and b-phases in the pristine PVDF were converted into a unique b-phase in the electrospun membranes.In addition,the solvent uptake percentage of the DMF/acetone(4:6)solvent system in a water medium(540)is much greater than that in an air medium(320),and over two times better than that of commercial polyethylene(PE)membranes(190).Similarly,the discharge capacity of the PVDF membrane separator prepared with the DMF/acetone(4:6)solvent system in a water medium is higher than that of the air medium.This enhancement of solvent uptake might be due to the interconnected porous morphology present in the water medium.展开更多
Porous carbon membranes were favorably fabricated through the pyrolysis of polyacrylonitrile(PAN) precursors, which were prepared with a template-free technique-thermally induced phase separation. These carbon membr...Porous carbon membranes were favorably fabricated through the pyrolysis of polyacrylonitrile(PAN) precursors, which were prepared with a template-free technique-thermally induced phase separation. These carbon membranes possess hierarchical pores, including cellular macropores across the whole membranes and much small pores in the matrix as well as on the pore walls. Nitrogen adsorption indicates micropores(1.47 and 1.84 nm) and mesopores(2.21 nm) exist inside the carbon membranes, resulting in their specific surface area as large as 1062 m2/g. The carbon membranes were used to adsorb organic dyes(methyl orange, Congo red, and rhodamine B) from aqueous solutions based on their advantages of hierarchical pore structures and large specific surface area. It is particularly noteworthy that the membranes present a selective adsorption towards methyl orange, whose molecular size(1.2 nm) is smaller than those of Congo red(2.3 nm) and rhodamine B(1.8 nm). This attractive result can be attributed to the steric structure matching between the molecular size and the pore size, rather than electrostatic attraction. Furthermore, the used carbon membranes can be easily regenerated by hydrochloric acid, and their recovery adsorption ratio maintains above 90% even in the third cycle. This work may provide a new route for carbon-based adsorbents with hierarchical pores via a template-free approach, which could be promisingly applied to selectively remove dye contaminants in aqueous effluents.展开更多
Isotactic polypropylene(iPP) and graphene oxide(GO), dispersed in dibutyl phthalate(DBP) and dioctyl phthalate(DOP), were blended to prepare organic-inorganic-blended microfiltration membranes using thermally ...Isotactic polypropylene(iPP) and graphene oxide(GO), dispersed in dibutyl phthalate(DBP) and dioctyl phthalate(DOP), were blended to prepare organic-inorganic-blended microfiltration membranes using thermally induced phase separation(TIPS). These membranes were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), contact angle measurements, mechanical properties, permeation tests, and porosity measurements. The morphology studied by SEM shows larger pores of the GO-blended membranes when compared to those of unmodified iPP membranes. Composite iPP/GO membranes achieve better performance in terms of water fluxes and pure water fluxes recovery ratio due to the hydrophilic nature of GO when compared with the pure iPP membranes. The addition of GO increases the permeability and the tensile strength by 352.98% and 123%, respectively, and also decreases the contact angle from 125° to 52.33°. We concluded that the composite membrane with 0.3% GO has the best antifouling ability of the membranes tested because it has the highest values of mean pore radius, porosity, and water flux observed in this study.展开更多
基金supported by Special Funds for Major State Basic Research Projects,China (No.2003CB615705).
文摘Ultra-high molecular weight polyethylene (UHMWPE) with a microporous structure was prepared via thermally induced phase separation (TIPS).Liquid paraffin (LP) was used as a diluent in the preparation of microporous UHMWPE. Small angle laser light scattering (SALLS) and differential scanning calorimetry (DSC) were used to determine the phase separation temperatures,i.e.the cloud points and the dynamic crystallization temperatures,respectively.It was found that the cloudI points were coincident with the cryst...
基金the financial support of the National Natural Science Foundation of China(Grant No.21606125)the Natural Science Foundation of Jiangsu Province(Grant No.BK20160984)+3 种基金the National Key R&D Program of China(Grant No.2017YFC0403702)the Materials-Oriented Chemical Engineering State Key Laboratory Program(KL16-09)the open project program of Jiangsu Key Lab for Chemistry of Low-Dimensional Materials(JSKC17005)the Priority Academic Program Development of Jiangsu Higher Education Institution(PAPD)。
文摘Ionic liquid(IL),1-butyl-3-methylimidazolium hexafluorophosphate([BMIM]PF6)as a new and environmentally friendly diluent was introduced to prepare poly(vinylidene fluoride)(PVDF)membranes via thermally induced phase separation(TIPS).Phase diagram of PVDF/[BMIM]PF6 was measured.The effects of polymer concentration and quenching temperature on the morphologies,properties,and performances of the PVDF membranes were investigated.When the polymer concentration was 15 wt%,the pure water flux of the fabricated membrane was up to nearly 2000 L·m-2·h-1,along with adequate mechanical strength.With the increasing of PVDF concentration and quenching temperature,mean pore size and water permeability of the membrane decreased.SEM results showed that PVDF membranes manufactured by ionic liquid(BMIm PF6)presented spherulite structure.And the PVDF membranes were represented asβphase by XRD and FTIR characterization.It provides a new way to prepare PVDF membranes with piezoelectric properties.
基金supported by the 863 program(No.2006AA03Z233)973 program(No.2009CB623402) of China
文摘High density polyethylene (HDPE)/polyethylene-block-poly(ethylene glycol) (PE-b-PEG) blend porous membranes were prepared via thermally induced phase separation (TIPS) process using diphenyl ether (DPE) as diluent. The phase diagrams of HDPE/PE-b-PEG/DPE systems were determined by optical microscopy and differential scanning calorimetry (DSC). By varying the content of PE-b-PEG, the effects of PE-b-PEG copolymer on morphology and crystalline structure of membranes were studied by scanning electron microscopy (SEM) and wide angle X-ray diffraction (WAXD). The chemical compositions of whole membranes and surface layers were characterized by elementary analysis, Fourier transform infrared spectroscopy-attenuated total reflection (FTIR-ATR) and X-ray photoelectron spectroscopy (XPS). Water contact angle, static protein adsorption and water flux experiments were used to evaluate the hydrophilicity, antifouling and water permeation properties of the membranes. It was found that the addition of PE-b-PEG increased the pore size of the obtained blend membranes. In the investigated range of PE-b-PEG content, the PEG blocks could not aggregate into obviously separated domains in membrane matrix. More importantly, PE-b-PEG could not only be retained stably in the membrane matrix during membrane formation, but also enrich at the membrane surface layer. Such stability and surface enrichment of PE-b-PEG endowed the blend membranes with improved hydrophilicity, protein absorption resistance and water permeation properties, which would be substantially beneficial to HDPE membranes for water treatment application.
基金National Natural Foundation of China(No.51003074)
文摘Poly(vinylidene fluoride) /polysulfone(PVDF/PSF) flat blend membrane was prepared via thermally induced phase separation(TIPS) technique.The membrane formation mechanism and membrane structure were investigated and the effects of PSF/PVDF weight ratio on morphology,crystallinity,porosity,and mechanical properties of the membrane were discussed.The relationship between membrane structure and performances,such as pure water flux and the rejection of carbonic black,was also discussed.It was found that solid-liquid(S-L) phase separation occurred for the PVDF/PSF/diluent system.The addition of PSF influences structure and crystallinity of the membrane,which in turn influences mechanical properties and performances of the membrane.The results reveal that it is possible to obtain network structure via S-L phase separation by blending the polymer,which has a partial compatibility with PVDF.
文摘A review of recent research related to micro- porous polymeric membranes formed via thermally induced phase separation (TIPS) and the morphologies of these membranes is presented. A summary of polymers and suitable diluents that can be used to prepare these microporous membranes via TIPS are summarized. The effects of different kinds of polymer materials, diluent types, cooling conditions, extractants and additive agents on the morphology and performance of TIPS membranes are also discussed. Finally new developments in TIPS technology are summarized.
基金supported by the National Natural Science Foundation of China(Grant No.22078146)the National Key R&D Program of China(Grant No.2020YFC0862903)+4 种基金the Natural Science Foundation of Jiangsu Province(Grant No.BK20200091)the Jiangsu Province Department of Human Resources and Social Security(Grant No.JNHB-036)the Materials-Oriented Chemical Engineering State Key Laboratory Program(Grant No.KL19-04)the Priority Academic Program Development of Jiangsu Higher Education Institution(PAPD).N.Tavajohi is grateful for financial support by the Kempe Foundation(Grant No.SMK-1850)Bio4energy program(Grant No.B4E3-TM-1-01).
文摘A non-toxic and environmentally safe diluent,acetyl tributyl citrate,was employed to prepare poly(vinylidene fluoride)-co-hexafluoropropylene membranes via thermally induced phase separation.Effects of the polymer concentration on the phase diagram,membrane morphology,hydrophobicity,pore size,porosity and mechanical properties(tensile stress and elongation at break)were investigated.The results showed that the pore size and porosity tended to decrease with increasing polymer concentration,whereas the contact angle,liquid entry pressure and mechanical properties showed the opposite trend.In direct contact membrane distillation operation with 3.5 wt-%sodium chloride solution as the feed solution,the prepared membranes performed high salt rejection(>99.9%).Furthermore,the prepared membranes retained excellent performance in long-term stability tests regarding the permeate flux and salt rejection. ne distillation.
基金supported by the National Natural Science Foundation of China(No.20874073)National 863(high-tech research and development) Program of China(No.2007AA030304)Tianjin Science and Technology Key Support Plan (No.08ZCGYGX03700).
文摘The asymmetric polyamide-6 (PA6) membranes were prepared by thermally induced phase separation. From the scanning electron microscopy (SEM) images, it is observed that with the increase of silicon dioxide (SiO2) content the structure of obtained membranes gradually varied from cellular structure to large ball-shaped cluster aggregates. Subsequently, with the addition of SiO2, pure water flux increased first and then decreased, while rejection showed the opposite trend. Besides, raising the coagulation bath temperature was favorable to increase pure water flux. Consequently, different membrane morphologies and performance were obtained by changing SiO2 content and coagulation bath temperature.
基金supported by the Natural Science Foundation of China(Grant No.51372042,51872053)Guangdong Provincial Natural Science Foundation(2015A030308004)the NSFCGuangdong Joint Fund(Grant No.U1501246).
文摘The effect of a N,N-dimethylformamide(DMF)/acetone solvent system(3:7,4:6,5:5,6:4,7:3)and spinning medium(air and water)on the membrane morphology and the structure-property relationship were investigated.A facile method was optimized to generate a porous,polymer-fiber membrane via the combinative effect of electrospinning and thermally inducing phase separation of the DMF/acetone(4:6)solvent system in a water medium.The attenuated total reflection(ATR)-Fourier transform infrared(FTIR)results showed an increased b-phase compared to the pristine poly(vinylidene fluoride)(PVDF).The XRD and DSC results further confirmed that the co-existing a-and b-phases in the pristine PVDF were converted into a unique b-phase in the electrospun membranes.In addition,the solvent uptake percentage of the DMF/acetone(4:6)solvent system in a water medium(540)is much greater than that in an air medium(320),and over two times better than that of commercial polyethylene(PE)membranes(190).Similarly,the discharge capacity of the PVDF membrane separator prepared with the DMF/acetone(4:6)solvent system in a water medium is higher than that of the air medium.This enhancement of solvent uptake might be due to the interconnected porous morphology present in the water medium.
基金financially supported by the National Natural Science Foundation of China(No.21174124)K.C.Wong Magna Fund in Ningbo University
文摘Porous carbon membranes were favorably fabricated through the pyrolysis of polyacrylonitrile(PAN) precursors, which were prepared with a template-free technique-thermally induced phase separation. These carbon membranes possess hierarchical pores, including cellular macropores across the whole membranes and much small pores in the matrix as well as on the pore walls. Nitrogen adsorption indicates micropores(1.47 and 1.84 nm) and mesopores(2.21 nm) exist inside the carbon membranes, resulting in their specific surface area as large as 1062 m2/g. The carbon membranes were used to adsorb organic dyes(methyl orange, Congo red, and rhodamine B) from aqueous solutions based on their advantages of hierarchical pore structures and large specific surface area. It is particularly noteworthy that the membranes present a selective adsorption towards methyl orange, whose molecular size(1.2 nm) is smaller than those of Congo red(2.3 nm) and rhodamine B(1.8 nm). This attractive result can be attributed to the steric structure matching between the molecular size and the pore size, rather than electrostatic attraction. Furthermore, the used carbon membranes can be easily regenerated by hydrochloric acid, and their recovery adsorption ratio maintains above 90% even in the third cycle. This work may provide a new route for carbon-based adsorbents with hierarchical pores via a template-free approach, which could be promisingly applied to selectively remove dye contaminants in aqueous effluents.
文摘Isotactic polypropylene(iPP) and graphene oxide(GO), dispersed in dibutyl phthalate(DBP) and dioctyl phthalate(DOP), were blended to prepare organic-inorganic-blended microfiltration membranes using thermally induced phase separation(TIPS). These membranes were characterized by scanning electron microscopy(SEM), Fourier transform infrared spectroscopy(FTIR), contact angle measurements, mechanical properties, permeation tests, and porosity measurements. The morphology studied by SEM shows larger pores of the GO-blended membranes when compared to those of unmodified iPP membranes. Composite iPP/GO membranes achieve better performance in terms of water fluxes and pure water fluxes recovery ratio due to the hydrophilic nature of GO when compared with the pure iPP membranes. The addition of GO increases the permeability and the tensile strength by 352.98% and 123%, respectively, and also decreases the contact angle from 125° to 52.33°. We concluded that the composite membrane with 0.3% GO has the best antifouling ability of the membranes tested because it has the highest values of mean pore radius, porosity, and water flux observed in this study.