To investigate the influence of various processing parameters on the mechanical properties of fibers,lignin/graphene oxide(GO)/poly(vinyl alcohol)(PVA)fibers with different mass ratios of lignin and GO to PVA were pre...To investigate the influence of various processing parameters on the mechanical properties of fibers,lignin/graphene oxide(GO)/poly(vinyl alcohol)(PVA)fibers with different mass ratios of lignin and GO to PVA were prepared by gel spinning technique.Air drawing process and spinneret diameters were tuned as the main factors.The tensile strength increased up to 472 MPa with air drawing process applied in 30L0.05GO0.72D-A PVA fibers(air-drawn PVA fibers reinforced by 30%lignin and 0.05%GO spun with a spinneret diameter of 0.72 mm),indicating 17.4%higher than that of the fiber without air drawing process(402 MPa).Similarly,at least a 14.6%increase in Young's modulus has been achieved for 30L0.05GO0.72D-A fiber.In addition,a smaller spinneret diameter(0.72 mm)also led to a 24.9%increase in tensile strength and a 7.7%increase in Young's modulus in comparison with those of 5L0.05GO0.84D-A fibers.展开更多
Porous poly(vinylidene fluoride)(PVDF)/poly(methyl methacrylate)(PMMA) blend five-bore hollow fiber membranes are prepared by wet phase inversion methods.In spinning these PVDF hollow fibers, N,N-dimethylacetamide(DMA...Porous poly(vinylidene fluoride)(PVDF)/poly(methyl methacrylate)(PMMA) blend five-bore hollow fiber membranes are prepared by wet phase inversion methods.In spinning these PVDF hollow fibers, N,N-dimethylacetamide(DMAc) and polyvinyl pyrrolidone(PVP) are used as the solvent and the non-solvent additive,respectively.The external coagulant uses water.The internal coagulants use water and DMAc-water solutions.The membranes are characterized in terms of water flux and molecular weight cut-off for the wet membranes.The cross-sectional structures are examined by scanning electron microscopy(SEM).The effects of polymer concentration and the internal coagulant on the permeation properties and membrane structures are examined keeping the bore liquid flow and air-gap constants.Relative high flux,rejection and strengh PVDF five-bore hollow fiber membranes could be prepared from the polymer concentration in dope solution at 17%of mass fraction,the air gap distance of 14 cm,and using 10%of mass fraction of DMAc solution as the internal coagulant at 13 mL/min of flow.展开更多
基金Fundamental Research Funds for the Central Universities,China(Nos.20D110110 and 2232020G-01)National Natural Science Foundation of China(No.51903033)Shanghai Sailing Program,China(No.19YF1400800)。
文摘To investigate the influence of various processing parameters on the mechanical properties of fibers,lignin/graphene oxide(GO)/poly(vinyl alcohol)(PVA)fibers with different mass ratios of lignin and GO to PVA were prepared by gel spinning technique.Air drawing process and spinneret diameters were tuned as the main factors.The tensile strength increased up to 472 MPa with air drawing process applied in 30L0.05GO0.72D-A PVA fibers(air-drawn PVA fibers reinforced by 30%lignin and 0.05%GO spun with a spinneret diameter of 0.72 mm),indicating 17.4%higher than that of the fiber without air drawing process(402 MPa).Similarly,at least a 14.6%increase in Young's modulus has been achieved for 30L0.05GO0.72D-A fiber.In addition,a smaller spinneret diameter(0.72 mm)also led to a 24.9%increase in tensile strength and a 7.7%increase in Young's modulus in comparison with those of 5L0.05GO0.84D-A fibers.
基金the China Postdoctoral Science Foundation (No.20110490645)the Science Foundation of Shanghai(No.11ZR1400800)
文摘Porous poly(vinylidene fluoride)(PVDF)/poly(methyl methacrylate)(PMMA) blend five-bore hollow fiber membranes are prepared by wet phase inversion methods.In spinning these PVDF hollow fibers, N,N-dimethylacetamide(DMAc) and polyvinyl pyrrolidone(PVP) are used as the solvent and the non-solvent additive,respectively.The external coagulant uses water.The internal coagulants use water and DMAc-water solutions.The membranes are characterized in terms of water flux and molecular weight cut-off for the wet membranes.The cross-sectional structures are examined by scanning electron microscopy(SEM).The effects of polymer concentration and the internal coagulant on the permeation properties and membrane structures are examined keeping the bore liquid flow and air-gap constants.Relative high flux,rejection and strengh PVDF five-bore hollow fiber membranes could be prepared from the polymer concentration in dope solution at 17%of mass fraction,the air gap distance of 14 cm,and using 10%of mass fraction of DMAc solution as the internal coagulant at 13 mL/min of flow.
