Microporous membranes of low-high density polyethylene and their blends were prepared bythermally-induced phase separation of polymer/long-aliphatic chain alcohol (diluent) mixtures.The microstructures of this particu...Microporous membranes of low-high density polyethylene and their blends were prepared bythermally-induced phase separation of polymer/long-aliphatic chain alcohol (diluent) mixtures.The microstructures of this particular membrane, which depends on the diluent properties,polymer concentration and cooling rate, were observed by scanning electron microscopy.'Beehive-type,'leafy-like, and lacy porous structure morphologies can be formed,depending onthe blend composition and phase separation conditions, which were discussed by the polymer anddiluent crystallization processes.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
Preparation and blood compatibility of different shape polyvinyl alcohol（PVA） membrane were investigated. Firstly, the tabular and tubular[polytetrafluoroethylene（PTFE） capillary as supporter] PVA membranes were p...Preparation and blood compatibility of different shape polyvinyl alcohol（PVA） membrane were investigated. Firstly, the tabular and tubular[polytetrafluoroethylene（PTFE） capillary as supporter] PVA membranes were prepared; then, methoxy polyethylene glycol（mPEG） was grafted onto the surface of the PVA membranes. The effects of the shape, structure and properties of the membrane surface on blood compatibility were studied in detail. The experiment results show that mPEG modified PVA membranes, especially mPEG modified tubular membrane, could availably repel the adhesion of the platelets. In addition, the anticoagulant mechanism of mPEG with a steric repulsion effectiveness was confirmed further via different grafting methods.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
Membranes were fabricated with high-density polyethylene (HDPE) and ethylene vinyl acetate (EVA) blend through thermally induced phase separation and were then used for vacuum membrane distillation (VMD). The membrane...Membranes were fabricated with high-density polyethylene (HDPE) and ethylene vinyl acetate (EVA) blend through thermally induced phase separation and were then used for vacuum membrane distillation (VMD). The membranes were supported by non woven polyester fabric with a special cellular structure. Different membrane samples were obtained by adjusting the polymer concentration, HDPE/EVA weight ratio, and coagulation bath temperature. The membranes were characterized by scanning electron microscopy (SEM) analysis, contact angle test, and evaluation of porosity and pore size distribution. A series of VMD tests were conducted using aqueous NaCI solution (0.5 mol·L^-1) at a feed temperature of 65 ℃ and permeate side absolute pressure of 3 kPa. The membranes showed excellent performance in water permeation flux, salt rejection, and long-term sta-bility. The HDPE/EVA co-blending membranes exhibited the largest permeation flux of 23.87 kg·m^-2·h^-1, and benign salt rejection of ≥99.9%.展开更多
Membranes from block copolymer poly(amide-12-b-ethylene oxide)(Pebax1074) and its blends with different molecular weight poly(ethylene glycol)(PEG)(200, 400, 600, 1500, 4600 and 8000) were prepared. The thermal proper...Membranes from block copolymer poly(amide-12-b-ethylene oxide)(Pebax1074) and its blends with different molecular weight poly(ethylene glycol)(PEG)(200, 400, 600, 1500, 4600 and 8000) were prepared. The thermal properties and structures of Pebax1074/PEG blend membranes were characterized by DSC and SEM, and the gas permeation properties of CO_2 and N_2 were also investigated at different temperatures. For Pebax1074/PEG blend membranes with low molecular weight PEG(MW≤ 600), higher gas permeabilities than Pebax1074 were achieved. The permeability increased with the increase of PEG molecular weight. The addition of low molecular weight PEG resulted in decrease in activation energy of permeation. For Pebax1074/PEG blend membranes with high molecular weight PEG(MW≥ 1500), due to the melt of PEO phase crystals, the gas permeation properties of blend membranes were temperaturedependent, which could be divided into crystalline region, transition region and amorphous region according to two different transition temperatures. PEG molecular weight and operation temperature determined different gas permeation properties of Pebax1074/PEG blend membranes in three regions. The activation energies of permeation in crystalline region were larger than those in amorphous region.展开更多
A novel mixed matrix nanofiltration membrane was constructed by coating a casting solution containing polyvinylidene fluoride(PVDF),polyethylene glycol(PEG)as hydrophilic agent,zeolitic like framework-67(ZIF-67),ethyl...A novel mixed matrix nanofiltration membrane was constructed by coating a casting solution containing polyvinylidene fluoride(PVDF),polyethylene glycol(PEG)as hydrophilic agent,zeolitic like framework-67(ZIF-67),ethylenediamine as cross-linking agent on Ag-nanoparticle-decorated polyester textile(PT)support(PT/AgNPs/PVDF-PEG/ZIF-67).PT/Ag-NPs/PVDF-PEG/ZIF-67 morphology,crystalline structure,surface chemical composition and hydrophilicity of PT/Ag-NPs/PVDF-PEG/ZIF-67 were fully characterized by field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR)and water contact angle technique,respectively.PT/Ag-NPs/PVDF-PEG/ZIF-67 was applied in cross module set-up for removal of contaminated water containing rose bengal(RB)dye.The effect of operational parameters such as dye concentration,solution pH and flow rate on performance of PT/Ag-NPs/PVDF-PEG/ZIF-67 were investigated and optimized by central composite design(CCD).Casting solution containing 0.5 wt.%ZIF-67 as optimum value showed the good wettability,high pure water flux(PWF;35.8 L·m-2·h-1),flux recovery ratio(FRR;90%),dye removal efficiency(96.41%).The selectivity factor of 12.72 and 14.42 was found to be for RB in the presence of amido black and methylene blue as interferent dyes,respectively,which showed a good selective recognition ability for RB dye.展开更多
文摘Microporous membranes of low-high density polyethylene and their blends were prepared bythermally-induced phase separation of polymer/long-aliphatic chain alcohol (diluent) mixtures.The microstructures of this particular membrane, which depends on the diluent properties,polymer concentration and cooling rate, were observed by scanning electron microscopy.'Beehive-type,'leafy-like, and lacy porous structure morphologies can be formed,depending onthe blend composition and phase separation conditions, which were discussed by the polymer anddiluent crystallization processes.
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Supported by the National Natural Science Foundation of China(No.29405038)
文摘Preparation and blood compatibility of different shape polyvinyl alcohol（PVA） membrane were investigated. Firstly, the tabular and tubular[polytetrafluoroethylene（PTFE） capillary as supporter] PVA membranes were prepared; then, methoxy polyethylene glycol（mPEG） was grafted onto the surface of the PVA membranes. The effects of the shape, structure and properties of the membrane surface on blood compatibility were studied in detail. The experiment results show that mPEG modified PVA membranes, especially mPEG modified tubular membrane, could availably repel the adhesion of the platelets. In addition, the anticoagulant mechanism of mPEG with a steric repulsion effectiveness was confirmed further via different grafting methods.
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.
基金Supported by the Natural Science Foundation of Tianjin(18JCZDJC37200)the State Key Laboratory of Separation Membranes and Membrane Processes of Tianjin Polytechnic University(M2-201610)+2 种基金the Tianjin higher school innovation team training program(TD13-5008)the Yangtze Scholars and Innovative Research Team in University(IRT-17R81)the Innovative Research Team of Tianjin Municipal Education Commission(TD12-5004)
文摘Membranes were fabricated with high-density polyethylene (HDPE) and ethylene vinyl acetate (EVA) blend through thermally induced phase separation and were then used for vacuum membrane distillation (VMD). The membranes were supported by non woven polyester fabric with a special cellular structure. Different membrane samples were obtained by adjusting the polymer concentration, HDPE/EVA weight ratio, and coagulation bath temperature. The membranes were characterized by scanning electron microscopy (SEM) analysis, contact angle test, and evaluation of porosity and pore size distribution. A series of VMD tests were conducted using aqueous NaCI solution (0.5 mol·L^-1) at a feed temperature of 65 ℃ and permeate side absolute pressure of 3 kPa. The membranes showed excellent performance in water permeation flux, salt rejection, and long-term sta-bility. The HDPE/EVA co-blending membranes exhibited the largest permeation flux of 23.87 kg·m^-2·h^-1, and benign salt rejection of ≥99.9%.
基金Financial support from the National Science and Technology Planning Project (No. 2011BAC08B00)the National High Technology Research and Development Program of China (863 Program) (No.2012AA03A611)
文摘Membranes from block copolymer poly(amide-12-b-ethylene oxide)(Pebax1074) and its blends with different molecular weight poly(ethylene glycol)(PEG)(200, 400, 600, 1500, 4600 and 8000) were prepared. The thermal properties and structures of Pebax1074/PEG blend membranes were characterized by DSC and SEM, and the gas permeation properties of CO_2 and N_2 were also investigated at different temperatures. For Pebax1074/PEG blend membranes with low molecular weight PEG(MW≤ 600), higher gas permeabilities than Pebax1074 were achieved. The permeability increased with the increase of PEG molecular weight. The addition of low molecular weight PEG resulted in decrease in activation energy of permeation. For Pebax1074/PEG blend membranes with high molecular weight PEG(MW≥ 1500), due to the melt of PEO phase crystals, the gas permeation properties of blend membranes were temperaturedependent, which could be divided into crystalline region, transition region and amorphous region according to two different transition temperatures. PEG molecular weight and operation temperature determined different gas permeation properties of Pebax1074/PEG blend membranes in three regions. The activation energies of permeation in crystalline region were larger than those in amorphous region.
文摘A novel mixed matrix nanofiltration membrane was constructed by coating a casting solution containing polyvinylidene fluoride(PVDF),polyethylene glycol(PEG)as hydrophilic agent,zeolitic like framework-67(ZIF-67),ethylenediamine as cross-linking agent on Ag-nanoparticle-decorated polyester textile(PT)support(PT/AgNPs/PVDF-PEG/ZIF-67).PT/Ag-NPs/PVDF-PEG/ZIF-67 morphology,crystalline structure,surface chemical composition and hydrophilicity of PT/Ag-NPs/PVDF-PEG/ZIF-67 were fully characterized by field emission scanning electron microscopy(FE-SEM),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FT-IR)and water contact angle technique,respectively.PT/Ag-NPs/PVDF-PEG/ZIF-67 was applied in cross module set-up for removal of contaminated water containing rose bengal(RB)dye.The effect of operational parameters such as dye concentration,solution pH and flow rate on performance of PT/Ag-NPs/PVDF-PEG/ZIF-67 were investigated and optimized by central composite design(CCD).Casting solution containing 0.5 wt.%ZIF-67 as optimum value showed the good wettability,high pure water flux(PWF;35.8 L·m-2·h-1),flux recovery ratio(FRR;90%),dye removal efficiency(96.41%).The selectivity factor of 12.72 and 14.42 was found to be for RB in the presence of amido black and methylene blue as interferent dyes,respectively,which showed a good selective recognition ability for RB dye.
