We report a simple preparation method of a renewable superhydrophobic surface by thermally induced phase separation (TIPS) and mechanical peeling. Porous polyvinylidene fluoride (PVDF) membranes with hierarchical ...We report a simple preparation method of a renewable superhydrophobic surface by thermally induced phase separation (TIPS) and mechanical peeling. Porous polyvinylidene fluoride (PVDF) membranes with hierarchical structures were prepared by a TIPS process under different cooling conditions, which were confirmed by scanning electron microscopy and mercury intrusion porosimetry. After peeling off the top layer, rough structures with hundreds of nanometers to several microns were obtained. A digital microscopy determines that the surface roughness of peeled PVDF membranes is much higher than that of the original PVDF membrane, which is important to obtain the superhydrophobicity. Water contact angle and sliding angle measurements demonstrate that the peeled membrane surfaces display super- hydrophobicity with a high contact angle (152°) and a low sliding angle (7.2°). Moreover, the superhydrophobicity can be easily recovered for many times by a simple mechanical peeling, identical to the original superhydrophobicity. This simple preparation method is low cost, and suitable for large-scale industrialization, which may offer more opportunities for practical applications.展开更多
Isotactic polypropylene (iPP) hollow fiber microporous membranes were prepared using thermally induced phase separation (TIPS) method. Di-n-butyl phthalate (DBP), dioctyl phthalate (DOP), and the mixed solvent...Isotactic polypropylene (iPP) hollow fiber microporous membranes were prepared using thermally induced phase separation (TIPS) method. Di-n-butyl phthalate (DBP), dioctyl phthalate (DOP), and the mixed solvent were used as diluents. The effect of α (DOP mass fraction in diluent) on the morphology and performance of the hollow fiber was investigated. With increasing α, the morphology of the resulting hollow fiber changes from typical cellular structure to mixed structure, and then to typical particulate structure. As a result, the permeability of the hollow fiber increases sharply, and the mechanical properties of the hollow fiber decrease obviously. It is suggested that the morphology and performances of iPP hollow fiber microporous membrane can be controlled via adjusting the compatibility between iPP and diluent.展开更多
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
Hydrophilic poly(vinyl butyral)(PVB) /Pluronic F127(F127) blend hollow fiber membranes were prepared via thermally induced phase separation(TIPS) ,and the effects of blend composition on the performance of hydrophilic...Hydrophilic poly(vinyl butyral)(PVB) /Pluronic F127(F127) blend hollow fiber membranes were prepared via thermally induced phase separation(TIPS) ,and the effects of blend composition on the performance of hydrophilic PVB/F127 blend hollow fiber membrane were investigated.The addition of F127 to PVB/polyethylene glycol(PEG) system decreases the cloud point temperature,while the cloud point temperature increases slightly with the addition of F127 to 20%(by mass) PVB/F127/PEG200 system when the concentration of F127 is not higher than 5%(by mass) .Light scattering results show that the initial inter-phase periodic distance formed from the phase separation of 20%(by mass) PVB/F127/PEG200 system decreases with the addition of F127,so does the growth rate during cooling process.The blend hollow fiber membrane prepared at air-gap 5mm,of which the water permeability increases and the rejection changes little with the increase of F127 concentration.For the membrane prepared at zero air-gap,both water permeability and rejection of the PVB/F127 blend membrane are greater than those of PVB membrane,while the tensile strength changes little.Elementary analysis shows that most F127 in the polymer solution can firmly exist in the polymer matrix,increasing the hydrophilicity of the blend membrane prepared at air-gap of 5mm.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
A systematic study of air gap distance effects on the structure and properties of poly(vinyl butyral)hollow fiber membrane via thermally induced phase separation(TIPS)has been carried out.The results show that the hol...A systematic study of air gap distance effects on the structure and properties of poly(vinyl butyral)hollow fiber membrane via thermally induced phase separation(TIPS)has been carried out.The results show that the hollow fiber membrane prepared at air gap zero has no skin layer; the pore size near the outer surface is larger than that near the inner surface; and the special pore channel-like structure near the outer surface is formed,which is quite different with the typical sponge-like structure caused by TIPS and the finger-like structure caused by non-solvent induced phase separation(NIPS),because of the synergistic action of non-solvent induced phase separation at air gap zero.The pore size gradually decreases from outer surface layer to the intermediate layer,but increases gradually from intermediate layer to the inner surface layer.With the increase of air gap distance,the pore size near the outer surface gets smaller and a dense skin layer is formed,and the pore size gradually increases from the outer surface layer to the inner surface layer.Water permeability of the hollow fiber membrane decreases with air gap distance,the water permeability decreases sharply from 45.50×10-7 to 4.52×10-7 m3/(m2·s·kPa)as air gap increases from 0 to 10 mm at take-up speed of 0.236 m/s,further decreases from 4.52×10-7 to 1.00×10-8 m3/(m2·s·kPa)as the air gap increases from 10 to 40 mm.Both the breaking strength and the elongation increase with the increase of air gap distance.The breaking strength increases from 2.25 MPa to 4.19 MPa and the elongation increases from 33.9% to 132.6% as air gap increases from 0 mm to 40 mm at take-up speed 0.236 m/s.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 (vinyl butyral) (PVB) hollow fiber membranes were fabricated via thermally induced phase separation (TIPS). The effects of coagulation bath temperature (CBT) on the structure and performance of membranes ...Poly (vinyl butyral) (PVB) hollow fiber membranes were fabricated via thermally induced phase separation (TIPS). The effects of coagulation bath temperature (CBT) on the structure and performance of membranes were investigated in detail. The morphologies of the membranes were studied by scanning electron microscopy (SEM), the performances of water permeability, rejection, breaking strength and elongation were measured, respectively. The results indicate that all the membranes have the asymmetric morphology and the thickness of the skin layer decreases and the pore size of the outer layer increases with the increase of CBT. The permeability of membranes prepared at air gap 1.0 cm and take-up speed 0.253 m/s increases from 1.047×10-7 to 5.909×10-7 m3/(m2·s-kPa) with the CBT increasing from 20 ℃ to 40℃, and sharply increases to 35.226×10 7 m3/(m2.s.kPa)once the CBT arrives at 50 ℃. While the carbonic ink rejections have no significant decrease, totally exceed 98%, but that of acid-maleic acid copolymer greatly decreases with the increase of CBT. Both the breaking strength and elongation decrease with the increase of CBT.展开更多
Microporous polyolefin hollow fiber membranes were prepared from high density polyethylene (HDPE)-paraffin solution via thermally induced phase separation (TIPS) method. Effects of extraction and cold-drawing cond...Microporous polyolefin hollow fiber membranes were prepared from high density polyethylene (HDPE)-paraffin solution via thermally induced phase separation (TIPS) method. Effects of extraction and cold-drawing condition on membrane structure and performance were investigated.Five volatile solvents were used as extractant. Dimension of hollow fiber and gas permeation rate of membrane were measured. Mierostructure of membrane was examined by Scanning Electronic Microscope (SEM). The results show that the membrane treated by pentane possesses a higher porosity, nitrogen permeability and lower shrinkage than those of membranes extracted by other three extractants. It is also found that the membrane stretched 133% shows the highest porosity and gas permeability in this study.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 escalating prevalence of anterior cruciate ligament(ACL)injuries in sports necessitates innovative strategies for ACL reconstruction.In this study,we propose a multiphasic bone-ligament-bone(BLB)integrated scaffol...The escalating prevalence of anterior cruciate ligament(ACL)injuries in sports necessitates innovative strategies for ACL reconstruction.In this study,we propose a multiphasic bone-ligament-bone(BLB)integrated scaffold as a potential solution.The BLB scaffold comprised two polylactic acid(PLA)/deferoxamine(DFO)@mesoporous hydroxyapatite(MHA)thermally induced phase separation(TIPS)scaffolds bridged by silk fibroin(SF)/connective tissue growth factor(CTGF)@Poly(L-lactide-co-ε-caprolactone)(PLCL)nanofiber yarn braided scaffold.This combination mimics the native architecture of the ACL tissue.The mechanical properties of the BLB scaffolds were determined to be compatible with the human ACL.In vitro experiments demonstrated that CTGF induced the expression of ligament-related genes,while TIPS scaffolds loaded with MHA and DFO enhanced the osteogenic-related gene expression of bone marrow stem cells(BMSCs)and promoted the migration and tubular formation of human umbilical vein endothelial cells(HUVECs).In rabbit models,the BLB scaffold efficiently facilitated ligamentization and graft-bone integration processes by providing bioactive substances.The double delivery of DFO and calcium ions by the BLB scaffold synergistically promoted bone regeneration,while CTGF improved collagen formation and ligament healing.Collectively,the findings indicate that the BLB scaffold exhibits substantial promise for ACL reconstruction.Additional investigation and advancement of this scaffold may yield enhanced results in the management of ACL injuries.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This work is supported by the National Natural Science Foundation of China (No.51403107), the Natural Science Foundation of Ningbo (No.2015A610014), the Key Laboratory of Marine Materials and Related Tech- nologies (No.2016K07), and K. C. Wong Magna Fund in Ningbo University.
文摘We report a simple preparation method of a renewable superhydrophobic surface by thermally induced phase separation (TIPS) and mechanical peeling. Porous polyvinylidene fluoride (PVDF) membranes with hierarchical structures were prepared by a TIPS process under different cooling conditions, which were confirmed by scanning electron microscopy and mercury intrusion porosimetry. After peeling off the top layer, rough structures with hundreds of nanometers to several microns were obtained. A digital microscopy determines that the surface roughness of peeled PVDF membranes is much higher than that of the original PVDF membrane, which is important to obtain the superhydrophobicity. Water contact angle and sliding angle measurements demonstrate that the peeled membrane surfaces display super- hydrophobicity with a high contact angle (152°) and a low sliding angle (7.2°). Moreover, the superhydrophobicity can be easily recovered for many times by a simple mechanical peeling, identical to the original superhydrophobicity. This simple preparation method is low cost, and suitable for large-scale industrialization, which may offer more opportunities for practical applications.
基金Supported by the National Natural Science Foundation of China (No.20236030).
文摘Isotactic polypropylene (iPP) hollow fiber microporous membranes were prepared using thermally induced phase separation (TIPS) method. Di-n-butyl phthalate (DBP), dioctyl phthalate (DOP), and the mixed solvent were used as diluents. The effect of α (DOP mass fraction in diluent) on the morphology and performance of the hollow fiber was investigated. With increasing α, the morphology of the resulting hollow fiber changes from typical cellular structure to mixed structure, and then to typical particulate structure. As a result, the permeability of the hollow fiber increases sharply, and the mechanical properties of the hollow fiber decrease obviously. It is suggested that the morphology and performances of iPP hollow fiber microporous membrane can be controlled via adjusting the compatibility between iPP and diluent.
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Supported by the National Natural Science Foundation of China(20776161)
文摘Hydrophilic poly(vinyl butyral)(PVB) /Pluronic F127(F127) blend hollow fiber membranes were prepared via thermally induced phase separation(TIPS) ,and the effects of blend composition on the performance of hydrophilic PVB/F127 blend hollow fiber membrane were investigated.The addition of F127 to PVB/polyethylene glycol(PEG) system decreases the cloud point temperature,while the cloud point temperature increases slightly with the addition of F127 to 20%(by mass) PVB/F127/PEG200 system when the concentration of F127 is not higher than 5%(by mass) .Light scattering results show that the initial inter-phase periodic distance formed from the phase separation of 20%(by mass) PVB/F127/PEG200 system decreases with the addition of F127,so does the growth rate during cooling process.The blend hollow fiber membrane prepared at air-gap 5mm,of which the water permeability increases and the rejection changes little with the increase of F127 concentration.For the membrane prepared at zero air-gap,both water permeability and rejection of the PVB/F127 blend membrane are greater than those of PVB membrane,while the tensile strength changes little.Elementary analysis shows that most F127 in the polymer solution can firmly exist in the polymer matrix,increasing the hydrophilicity of the blend membrane prepared at air-gap of 5mm.
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Project(21176264)supported by the National Natural Science Foundation of ChinaProject(11JJ2010)supported by the Natural Science Foundation of Hunan Province,China
文摘A systematic study of air gap distance effects on the structure and properties of poly(vinyl butyral)hollow fiber membrane via thermally induced phase separation(TIPS)has been carried out.The results show that the hollow fiber membrane prepared at air gap zero has no skin layer; the pore size near the outer surface is larger than that near the inner surface; and the special pore channel-like structure near the outer surface is formed,which is quite different with the typical sponge-like structure caused by TIPS and the finger-like structure caused by non-solvent induced phase separation(NIPS),because of the synergistic action of non-solvent induced phase separation at air gap zero.The pore size gradually decreases from outer surface layer to the intermediate layer,but increases gradually from intermediate layer to the inner surface layer.With the increase of air gap distance,the pore size near the outer surface gets smaller and a dense skin layer is formed,and the pore size gradually increases from the outer surface layer to the inner surface layer.Water permeability of the hollow fiber membrane decreases with air gap distance,the water permeability decreases sharply from 45.50×10-7 to 4.52×10-7 m3/(m2·s·kPa)as air gap increases from 0 to 10 mm at take-up speed of 0.236 m/s,further decreases from 4.52×10-7 to 1.00×10-8 m3/(m2·s·kPa)as the air gap increases from 10 to 40 mm.Both the breaking strength and the elongation increase with the increase of air gap distance.The breaking strength increases from 2.25 MPa to 4.19 MPa and the elongation increases from 33.9% to 132.6% as air gap increases from 0 mm to 40 mm at take-up speed 0.236 m/s.
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Project(21176264)supported by the National Natural Science Foundation of ChinaProject(11JJ2010)supported by the Hunan Provincial Natural Science Foundation of China
文摘Poly (vinyl butyral) (PVB) hollow fiber membranes were fabricated via thermally induced phase separation (TIPS). The effects of coagulation bath temperature (CBT) on the structure and performance of membranes were investigated in detail. The morphologies of the membranes were studied by scanning electron microscopy (SEM), the performances of water permeability, rejection, breaking strength and elongation were measured, respectively. The results indicate that all the membranes have the asymmetric morphology and the thickness of the skin layer decreases and the pore size of the outer layer increases with the increase of CBT. The permeability of membranes prepared at air gap 1.0 cm and take-up speed 0.253 m/s increases from 1.047×10-7 to 5.909×10-7 m3/(m2·s-kPa) with the CBT increasing from 20 ℃ to 40℃, and sharply increases to 35.226×10 7 m3/(m2.s.kPa)once the CBT arrives at 50 ℃. While the carbonic ink rejections have no significant decrease, totally exceed 98%, but that of acid-maleic acid copolymer greatly decreases with the increase of CBT. Both the breaking strength and elongation decrease with the increase of CBT.
基金Supported by Zhejiang Natural Science Foundation (ZJNSF Y404096) and SRF for ROCS ,SEM
文摘Microporous polyolefin hollow fiber membranes were prepared from high density polyethylene (HDPE)-paraffin solution via thermally induced phase separation (TIPS) method. Effects of extraction and cold-drawing condition on membrane structure and performance were investigated.Five volatile solvents were used as extractant. Dimension of hollow fiber and gas permeation rate of membrane were measured. Mierostructure of membrane was examined by Scanning Electronic Microscope (SEM). The results show that the membrane treated by pentane possesses a higher porosity, nitrogen permeability and lower shrinkage than those of membranes extracted by other three extractants. It is also found that the membrane stretched 133% shows the highest porosity and gas permeability in this study.
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 Fundamental Research Funds for the Central Universities(2232019A3-07,2232019D3-20)the Science and Technology Commission of Shanghai Municipality(20S31900900,20DZ2254900)+8 种基金the Sino German Science Foundation Research Exchange Center(M0263)the National Natural Science Foundation of China(82102579,81871753)the Shanghai Rising-Star Program(22QC1401200)the Basic Scientific Research Project of Shanghai Sixth People’s Hospital(ynqn202101)the Opening Project of National Engineering Laboratory for Modern Silk,Soochow University(SDGC2149)the National Key Research and Development Program of China(2018YFC1106200,2018YFC1106202)the Key R&D Program of Shandong province(2019JZZY011104)the Deutsche Forschungsgemeinschaft(German Research Foundation(B.R.:RO 2511/11-1),This project was also supported by Researchers Supporting Project Number(RSP2023R65)King Saud University,Riyadh,Saudi Arabia,and the combined Sino-German Mobility Programme of the National Natural Science Foundation of China(NSFC)/Deutsche Forschungsgemeinschaft(German Research Foundation(B.R.:M0332).
文摘The escalating prevalence of anterior cruciate ligament(ACL)injuries in sports necessitates innovative strategies for ACL reconstruction.In this study,we propose a multiphasic bone-ligament-bone(BLB)integrated scaffold as a potential solution.The BLB scaffold comprised two polylactic acid(PLA)/deferoxamine(DFO)@mesoporous hydroxyapatite(MHA)thermally induced phase separation(TIPS)scaffolds bridged by silk fibroin(SF)/connective tissue growth factor(CTGF)@Poly(L-lactide-co-ε-caprolactone)(PLCL)nanofiber yarn braided scaffold.This combination mimics the native architecture of the ACL tissue.The mechanical properties of the BLB scaffolds were determined to be compatible with the human ACL.In vitro experiments demonstrated that CTGF induced the expression of ligament-related genes,while TIPS scaffolds loaded with MHA and DFO enhanced the osteogenic-related gene expression of bone marrow stem cells(BMSCs)and promoted the migration and tubular formation of human umbilical vein endothelial cells(HUVECs).In rabbit models,the BLB scaffold efficiently facilitated ligamentization and graft-bone integration processes by providing bioactive substances.The double delivery of DFO and calcium ions by the BLB scaffold synergistically promoted bone regeneration,while CTGF improved collagen formation and ligament healing.Collectively,the findings indicate that the BLB scaffold exhibits substantial promise for ACL reconstruction.Additional investigation and advancement of this scaffold may yield enhanced results in the management of ACL injuries.
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.