CN115501764A - Waterproof breathable film with gradient pore structure and preparation method and application thereof - Google Patents
Waterproof breathable film with gradient pore structure and preparation method and application thereof Download PDFInfo
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- CN115501764A CN115501764A CN202211277969.4A CN202211277969A CN115501764A CN 115501764 A CN115501764 A CN 115501764A CN 202211277969 A CN202211277969 A CN 202211277969A CN 115501764 A CN115501764 A CN 115501764A
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- 239000011148 porous material Substances 0.000 title claims abstract description 35
- 238000002360 preparation method Methods 0.000 title claims abstract description 18
- 238000009987 spinning Methods 0.000 claims abstract description 100
- 239000002346 layers by function Substances 0.000 claims abstract description 82
- 238000000034 method Methods 0.000 claims abstract description 78
- 239000010410 layer Substances 0.000 claims abstract description 74
- 238000010041 electrostatic spinning Methods 0.000 claims abstract description 52
- 239000002033 PVDF binder Substances 0.000 claims description 30
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 30
- 239000012982 microporous membrane Substances 0.000 claims description 28
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 claims description 24
- -1 polypropylene Polymers 0.000 claims description 23
- 239000002904 solvent Substances 0.000 claims description 19
- URAYPUMNDPQOKB-UHFFFAOYSA-N triacetin Chemical compound CC(=O)OCC(OC(C)=O)COC(C)=O URAYPUMNDPQOKB-UHFFFAOYSA-N 0.000 claims description 18
- 239000004743 Polypropylene Substances 0.000 claims description 17
- 238000001914 filtration Methods 0.000 claims description 17
- 238000002156 mixing Methods 0.000 claims description 16
- 229920001155 polypropylene Polymers 0.000 claims description 16
- DOIRQSBPFJWKBE-UHFFFAOYSA-N dibutyl phthalate Chemical compound CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 claims description 14
- 238000003756 stirring Methods 0.000 claims description 13
- 229920002492 poly(sulfone) Polymers 0.000 claims description 12
- 238000001816 cooling Methods 0.000 claims description 11
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 claims description 9
- 235000013773 glyceryl triacetate Nutrition 0.000 claims description 9
- 238000009998 heat setting Methods 0.000 claims description 9
- 239000004745 nonwoven fabric Substances 0.000 claims description 9
- 229960002622 triacetin Drugs 0.000 claims description 9
- 239000000463 material Substances 0.000 claims description 8
- 229920001343 polytetrafluoroethylene Polymers 0.000 claims description 8
- 239000004810 polytetrafluoroethylene Substances 0.000 claims description 8
- 229920005989 resin Polymers 0.000 claims description 8
- 239000011347 resin Substances 0.000 claims description 8
- 229920001169 thermoplastic Polymers 0.000 claims description 8
- 239000004416 thermosoftening plastic Substances 0.000 claims description 8
- ZFMQKOWCDKKBIF-UHFFFAOYSA-N bis(3,5-difluorophenyl)phosphane Chemical compound FC1=CC(F)=CC(PC=2C=C(F)C=C(F)C=2)=C1 ZFMQKOWCDKKBIF-UHFFFAOYSA-N 0.000 claims description 7
- 229920000840 ethylene tetrafluoroethylene copolymer Polymers 0.000 claims description 7
- 238000002844 melting Methods 0.000 claims description 7
- 230000008018 melting Effects 0.000 claims description 7
- YEJRWHAVMIAJKC-UHFFFAOYSA-N 4-Butyrolactone Chemical compound O=C1CCCO1 YEJRWHAVMIAJKC-UHFFFAOYSA-N 0.000 claims description 6
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 claims description 6
- FLKPEMZONWLCSK-UHFFFAOYSA-N diethyl phthalate Chemical compound CCOC(=O)C1=CC=CC=C1C(=O)OCC FLKPEMZONWLCSK-UHFFFAOYSA-N 0.000 claims description 6
- 238000002074 melt spinning Methods 0.000 claims description 6
- 239000000203 mixture Substances 0.000 claims description 6
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 6
- 239000004800 polyvinyl chloride Substances 0.000 claims description 6
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 6
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 claims description 5
- 239000004698 Polyethylene Substances 0.000 claims description 5
- 229920001577 copolymer Polymers 0.000 claims description 5
- 229910052731 fluorine Inorganic materials 0.000 claims description 5
- 239000011737 fluorine Substances 0.000 claims description 5
- 229920000728 polyester Polymers 0.000 claims description 5
- 229920000573 polyethylene Polymers 0.000 claims description 5
- 239000002861 polymer material Substances 0.000 claims description 5
- 229920001780 ECTFE Polymers 0.000 claims description 4
- 239000004417 polycarbonate Substances 0.000 claims description 4
- 229920000515 polycarbonate Polymers 0.000 claims description 4
- PYGXAGIECVVIOZ-UHFFFAOYSA-N Dibutyl decanedioate Chemical compound CCCCOC(=O)CCCCCCCCC(=O)OCCCC PYGXAGIECVVIOZ-UHFFFAOYSA-N 0.000 claims description 3
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 claims description 3
- 239000004952 Polyamide Substances 0.000 claims description 3
- 239000004695 Polyether sulfone Substances 0.000 claims description 3
- 239000004793 Polystyrene Substances 0.000 claims description 3
- MIMDHDXOBDPUQW-UHFFFAOYSA-N dioctyl decanedioate Chemical compound CCCCCCCCOC(=O)CCCCCCCCC(=O)OCCCCCCCC MIMDHDXOBDPUQW-UHFFFAOYSA-N 0.000 claims description 3
- 238000001125 extrusion Methods 0.000 claims description 3
- 229920002647 polyamide Polymers 0.000 claims description 3
- 229920006393 polyether sulfone Polymers 0.000 claims description 3
- 229920006254 polymer film Polymers 0.000 claims description 3
- 229920002223 polystyrene Polymers 0.000 claims description 3
- 229920000874 polytetramethylene terephthalate Polymers 0.000 claims description 3
- HXJUTPCZVOIRIF-UHFFFAOYSA-N sulfolane Chemical compound O=S1(=O)CCCC1 HXJUTPCZVOIRIF-UHFFFAOYSA-N 0.000 claims description 3
- DQWPFSLDHJDLRL-UHFFFAOYSA-N triethyl phosphate Chemical compound CCOP(=O)(OCC)OCC DQWPFSLDHJDLRL-UHFFFAOYSA-N 0.000 claims description 3
- 229920002313 fluoropolymer Polymers 0.000 claims description 2
- 239000004811 fluoropolymer Substances 0.000 claims description 2
- 239000010865 sewage Substances 0.000 claims description 2
- 238000001523 electrospinning Methods 0.000 claims 2
- 229920005992 thermoplastic resin Polymers 0.000 claims 1
- 239000012528 membrane Substances 0.000 abstract description 46
- 230000008569 process Effects 0.000 abstract description 11
- 239000013505 freshwater Substances 0.000 abstract description 5
- 239000003344 environmental pollutant Substances 0.000 abstract description 3
- 231100000719 pollutant Toxicity 0.000 abstract description 3
- 238000011010 flushing procedure Methods 0.000 abstract description 2
- 230000010287 polarization Effects 0.000 abstract description 2
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 16
- 238000004821 distillation Methods 0.000 description 12
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 12
- 239000011780 sodium chloride Substances 0.000 description 8
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 6
- 230000004907 flux Effects 0.000 description 6
- 150000003839 salts Chemical class 0.000 description 6
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 4
- 230000035699 permeability Effects 0.000 description 4
- 239000000835 fiber Substances 0.000 description 3
- 238000000926 separation method Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 238000005303 weighing Methods 0.000 description 3
- 229920007925 Ethylene chlorotrifluoroethylene (ECTFE) Polymers 0.000 description 2
- XSTXAVWGXDQKEL-UHFFFAOYSA-N Trichloroethylene Chemical group ClC=C(Cl)Cl XSTXAVWGXDQKEL-UHFFFAOYSA-N 0.000 description 2
- 230000001276 controlling effect Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000002209 hydrophobic effect Effects 0.000 description 2
- 230000003647 oxidation Effects 0.000 description 2
- 238000007254 oxidation reaction Methods 0.000 description 2
- 229920000642 polymer Polymers 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- UBOXGVDOUJQMTN-UHFFFAOYSA-N trichloroethylene Natural products ClCC(Cl)Cl UBOXGVDOUJQMTN-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 238000010612 desalination reaction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 235000015203 fruit juice Nutrition 0.000 description 1
- 239000001087 glyceryl triacetate Substances 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000008235 industrial water Substances 0.000 description 1
- 230000008595 infiltration Effects 0.000 description 1
- 238000001764 infiltration Methods 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 238000000614 phase inversion technique Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 238000001223 reverse osmosis Methods 0.000 description 1
- 239000013535 sea water Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 238000002145 thermally induced phase separation Methods 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
- 238000009736 wetting Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/02—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor characterised by their properties
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0002—Organic membrane manufacture
- B01D67/0006—Organic membrane manufacture by chemical reactions
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/44—Treatment of water, waste water, or sewage by dialysis, osmosis or reverse osmosis
Abstract
The invention discloses a waterproof breathable film with a gradient pore structure and a preparation method and application thereof, wherein the waterproof breathable film comprises a supporting layer and a waterproof breathable functional layer, and the waterproof breathable functional layer is spun on the surface of the supporting layer by an electrostatic spinning method; the aperture of the waterproof breathable film from the supporting layer to the waterproof breathable functional layer is gradually reduced. The gradient pore structure is prepared by spinning layer by layer, and the membrane spun by the electrostatic spinning method is thin, large in porosity and easy to control in pore size; the reverse flushing of the membrane is facilitated, the concentration polarization is reduced, and the pollution on the surface of the membrane is avoided, so that the phenomenon that pollutants leak into the fresh water side is reduced; the preparation method of the invention has simple process and easily controlled process conditions, and is a brand new method for preparing the waterproof breathable film.
Description
Technical Field
The invention relates to the technical field of preparation of water treatment separation membranes, in particular to a waterproof breathable membrane with a gradient pore structure and a preparation method and application thereof.
Background
Membrane distillation is a new membrane technology developed in recent years, which organically combines the characteristics of distillation with those of membranes. In the membrane distillation process, the vapor mass transfer condensation process in the conventional distillation and the membrane separation process of separating substances diffusing and permeating the membrane are adopted. It avoids the defects of easy scaling and corrosion resistance of the distillation method and the need of high-pressure operation of the reverse osmosis method. Can be used for pure water production (seawater and brackish water desalination, power plant boiler water and semiconductor industrial water), solution concentration (wastewater treatment, fruit juice concentration, salt and acid concentration) and volatile biological product removal.
Membranes that can be successfully used in membrane distillation processes must be non-hydrophilic and porous, and polymeric membrane materials that meet this condition should have low surface energy, i.e., good hydrophobic properties, such as polycarbonate, polyester, polyethylene, polypropylene, halogenated polyethylene, fluoropolymers, and the like. The common membrane for membrane distillation includes Polytetrafluoroethylene (PTFE) membrane, polyvinylidene fluoride (PVDF) membrane, and polypropylene (PP) membrane. PTFE membranes are most hydrophobic and have better oxidation resistance and chemical stability than the other two membranes, which makes PTFE membranes very versatile in terms of the systems used, next to PVDF membranes. Although the chemical stability and oxidation resistance of the PP film are relatively poor, the PP film has wide market application due to low price.
Although the membrane distillation technology has been studied internationally since the 60's in the 20 th century, the research on this new membrane separation process has been going into depth in recent decades, but the technology has not been applied industrially on a large scale. The reason is mainly as follows: (1) the water flux of the practical membrane is low; (2) the membrane pollution in the operation process of membrane distillation not only causes the reduction of membrane flux, but also more importantly accelerates the wetting of the membrane, so that impurities such as salt and the like leak into the fresh water side, and the quality of the fresh water is reduced; (3) in addition, the conventional phase inversion method, mechanical stretching method and thermally induced phase separation method have not yet been developed for the preparation of porous films.
The waterproof breathable film is a novel high-molecular waterproof material, and water vapor can permeate to the capillary (film) along the micropores of the waterproof film to reach the other side, so that the breathable phenomenon is generated. It can prevent the emergence of the infiltration phenomenon of water and isolate liquid such as water outside to make waterproof ventilated membrane really possess waterproof ventilative function, avoided traditional membrane distillation operation in-process membrane to be moistened, the phenomenon that the pollutant seepage went into the fresh water side takes place. The electrostatic spinning method can prepare thinner membranes, can better regulate and control the pore structure of the membranes, enables the porosity, the pore diameter and the distribution of the membranes to be more reasonable, and is suitable for the membrane distillation process.
Disclosure of Invention
The invention aims to overcome the defects of the membrane preparation technology for membrane distillation and the membrane operation process thereof in the prior art, and provides a waterproof breathable membrane with a gradient pore structure.
In order to achieve the aim, the waterproof breathable film with the gradient pore structure comprises a supporting layer and a waterproof breathable functional layer, wherein the waterproof breathable functional layer is spun on the surface of the supporting layer by an electrostatic spinning method; the aperture of the waterproof breathable film from the supporting layer to the waterproof breathable functional layer is gradually reduced.
The invention also aims to provide a preparation method of the waterproof breathable film with the gradient pore structure, which is simple and easy to control process conditions so as to prepare the waterproof breathable film with excellent performance.
In order to achieve the aim, the preparation method of the waterproof breathable film with the gradient pore structure comprises the following steps:
s1, preparing a spinning solution of a waterproof and breathable functional layer: at the temperature of 50-300 ℃, the mass concentration is 10-30: 70-90 fluorine-containing polymer material and solvent are mixed, stirred and dissolved, and then the mixture is prepared after filtration and deaeration;
s2, preparing a waterproof and breathable functional layer: spinning the waterproof breathable functional layer spinning solution on the supporting layer by adopting an electrostatic spinning method;
s3, preparing a waterproof breathable film: the waterproof breathable functional layer/supporting layer is prepared by heat setting.
According to the present invention, the fluorine-containing polymer material in step S1 is polyvinylidene fluoride (PVDF), PVDF/hexafluoropropylene copolymer, ethylene-tetrafluoroethylene (ETFE), or ethylene-chlorotrifluoroethylene (ECTFE).
According to the invention, the solvent in step S1 is one of N, N-dimethylformamide, N-dimethylacetamide, dibutyl phthalate, diethyl phthalate, dioctyl sebacate, dibutyl sebacate, dioctyl adipate, glycerol triacetate, sulfolane and gamma-butyrolactone.
According to the invention, the voltage of the electrostatic spinning in step S2 is 10-40 kV.
Preferably, the voltage of the electrostatic spinning is 15 to 30kV.
According to the invention, the support layer in step S2 is a nonwoven fabric or a microporous membrane.
Furthermore, the non-woven fabric is made of PP or PET.
Further, the microporous membrane is prepared by a melt spinning method or an electrostatic spinning method.
The method for preparing the microporous membrane by the melt spinning method specifically comprises the following steps: melting thermoplastic slice resin in a screw extruder, extruding into melt trickle through a spinneret plate, stretching, cooling and obtaining the thermoplastic slice resin by a flat screen type receiving device.
According to the invention, the thermoplastic slice resin is one of polypropylene, polyvinyl chloride, polyvinylidene fluoride, polyester, polyamide, polyethylene, polytetrafluoroethylene, polycarbonate, polyacrylonitrile, polytetramethylene terephthalate or polystyrene.
According to the invention, the melting temperature is between 100 and 350 ℃.
According to the invention, the extrusion temperature is between 200 and 400 ℃.
According to the invention, the electrostatic spinning method for preparing the microporous membrane comprises the following steps:
s1, at the temperature of 50-90 ℃, mixing the components with the mass concentration of 12-30: 70-82, mixing, stirring and dissolving the macromolecular film-forming material and a solvent, and filtering and defoaming the mixture to obtain spinning solution;
and S2, spinning the spinning solution into a microporous membrane by adopting an electrostatic spinning method.
According to the invention, the polymer film forming material in the step S1 is one of polyvinylidene fluoride, polysulfone, polyethersulfone, polyvinyl chloride and polyacrylonitrile.
According to the present invention, the solvent in step S1 is one of N, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, and triethyl phosphate.
According to the invention, the voltage of the electrostatic spinning in step S2 is 10-40 kV.
Preferably, the voltage of the electrostatic spinning is 15 to 30kV.
According to the invention, the heat-setting temperature in step S3 is 140 to 250 ℃.
In the preparation method of the waterproof breathable film, in the step S1, the waterproof breathable functional layer spinning solutions with different mass concentrations are prepared, and the waterproof breathable functional layer spinning solutions are spun on the support layer by layer in the order of high mass concentration to low mass concentration by an electrostatic spinning method.
In the process of preparing the microporous membrane by the electrostatic spinning method, in the step S1, the spinning solutions with different mass concentrations are prepared, and the microporous membrane is prepared by spinning the spinning solutions layer by layer according to the sequence of the mass concentrations from high to low by adopting the electrostatic spinning method.
The invention further aims to provide application of the waterproof breathable film with the gradient pore structure in sewage treatment.
Compared with the prior art, the invention has the following advantages:
1) The aperture of the waterproof breathable film with the gradient pore structure is gradually reduced from the supporting layer to the waterproof breathable functional layer, the range of the aperture is 0.1-2 mu m, the gradient pore structure is favorable for the reverse flushing of the film, the concentration polarization is reduced, and the pollution on the surface of the film is avoided, so that the phenomenon that pollutants leak into the fresh water side is reduced;
2) The waterproof breathable film with the gradient pore structure is obtained by spinning layer by layer, and the film spun by the electrostatic spinning method is thin, large in porosity and easy to control in pore size; the pore size of the spinning membrane can be regulated and controlled by controlling the concentration of the spinning solution and the electrostatic spinning process thereof, so that the membrane with a gradient pore structure is prepared;
3) The waterproof breathable film with the gradient pore structure can also be obtained by adopting a method combining a melt-blown spinning method and an electrostatic spinning method, and the melt-blown spinning method is easy to control the thickness of fibers so as to control the pore diameter of the microporous support film; then spinning one layer or layer by an electrostatic spinning method to prepare a membrane with a gradient pore structure;
4) The preparation method of the waterproof breathable film with the gradient pore structure is simple in process and easy to control process conditions, and is a brand-new method for preparing the waterproof breathable film.
Detailed Description
The invention discloses a preparation method of a waterproof breathable film with a gradient pore structure, which comprises the following steps:
s1, preparing a spinning solution of a waterproof and breathable functional layer: at the temperature of 50-300 ℃, the mass concentration is 10-30: 70-90 fluorine-containing polymer material and solvent are mixed, stirred and dissolved, and then the mixture is prepared after filtration and deaeration;
s2, preparing a waterproof and breathable functional layer: spinning the waterproof breathable functional layer spinning solution on the supporting layer by adopting an electrostatic spinning method;
s3, preparing a waterproof breathable film: the waterproof breathable functional layer/supporting layer is prepared by heat setting.
According to the present invention, the fluorine-containing polymer material in step S1 is polyvinylidene fluoride (PVDF), PVDF/hexafluoropropylene copolymer, ethylene-tetrafluoroethylene (ETFE), or ethylene-chlorotrifluoroethylene (ECTFE).
According to the invention, the solvent in step S1 is one of N, N-dimethylformamide, N-dimethylacetamide, dibutyl phthalate, diethyl phthalate, dioctyl sebacate, dibutyl sebacate, dioctyl adipate, glycerol triacetate, sulfolane and gamma-butyrolactone.
According to the invention, the voltage of the electrostatic spinning in step S2 is 10-40 kV.
Preferably, the voltage of the electrostatic spinning is 15 to 30kV.
According to the invention, the support layer in step S2 is a nonwoven fabric or a microporous membrane.
Furthermore, the non-woven fabric is made of PP or PET.
Further, the microporous membrane is prepared by a melt spinning method or an electrostatic spinning method.
The method for preparing the microporous membrane by the melt spinning method is characterized in that high-speed hot air is utilized to draw polymer melt trickle extruded from spinneret orifices, so that superfine fibers are formed and are condensed on a net curtain, and the microporous membrane is formed by self adhesion. Microporous membranes with different pore diameters can be prepared by controlling the thickness of the superfine fibers. The method specifically comprises the following steps: melting thermoplastic slice resin in a screw extruder, extruding into melt trickle by a spinneret plate, stretching, cooling and obtaining the thermoplastic slice resin by a flat screen type receiving device.
According to the invention, the thermoplastic slice resin is one of polypropylene, polyvinyl chloride, polyvinylidene fluoride, polyester, polyamide, polyethylene, polytetrafluoroethylene, polycarbonate, polyacrylonitrile, polytetramethylene terephthalate or polystyrene.
According to the invention, the melting temperature is between 100 and 350 ℃.
According to the invention, the extrusion temperature is between 200 and 400 ℃.
According to the invention, the method for preparing the microporous membrane by the electrostatic spinning method comprises the following steps:
s1, at the temperature of 50-90 ℃, mixing the components with the mass concentration of 12-30: 70-82, mixing, stirring and dissolving the polymer film-forming material and a solvent, and filtering and defoaming to prepare a spinning solution;
and S2, spinning the spinning solution into a microporous membrane by adopting an electrostatic spinning method.
According to the invention, the polymer film forming material in the step S1 is one of polyvinylidene fluoride, polysulfone, polyethersulfone, polyvinyl chloride and polyacrylonitrile.
According to the present invention, the solvent in step S1 is one of N, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, and triethyl phosphate.
According to the invention, the voltage of the electrostatic spinning in step S2 is 10-40 kV.
Preferably, the voltage of the electrostatic spinning is 15 to 30kV.
In the preparation method of the waterproof breathable film, in the step S1, the waterproof breathable functional layer spinning solutions with different mass concentrations are prepared, and the waterproof breathable functional layer spinning solutions are spun on the support layer by layer in the order of high mass concentration to low mass concentration by an electrostatic spinning method.
The waterproof and breathable functional layer with the gradient pore structure can be prepared by the layer-by-layer spinning method, namely the pore diameter of the waterproof and breathable functional layer is gradually reduced from the supporting layer to the functional layer.
In the process of preparing the microporous membrane by the electrostatic spinning method, in the step S1, the spinning solutions with different mass concentrations are prepared, and the microporous membrane is prepared by spinning the spinning solutions layer by layer according to the sequence of the mass concentrations from high to low by adopting the electrostatic spinning method.
The microporous membrane with a gradient pore structure can be prepared by the layer-by-layer spinning method, namely the pore diameter of the microporous membrane is gradually reduced from the bottom layer to the upper layer (namely the surface contacted with the waterproof breathable functional layer).
Example 1
1) Preparing a spinning solution of a waterproof and breathable functional layer: mixing, stirring and dissolving 1.5g of PVDF/hexafluoropropylene copolymer and 8.5g of dibutyl phthalate at 180 ℃, filtering and defoaming to prepare a waterproof and breathable functional layer spinning solution with the mass concentration of 15%; weighing 2g of PVDF/hexafluoropropylene copolymer and 8g of dibutyl phthalate, mixing, stirring and dissolving at 200 ℃, and filtering and defoaming to prepare a waterproof and breathable functional layer spinning solution with the mass concentration of 20%;
2) Preparing a waterproof breathable functional layer: sucking the spinning solution of the waterproof and breathable functional layer with the mass concentration of 20% into a syringe needle tube of an injector, spinning the spinning solution on the surface of a PP non-woven fabric by adopting an electrostatic spinning method (the voltage is 40kV, the distance between a needle point and a polyester non-woven fabric is 10 cm), cooling the PP non-woven fabric by air, and extracting a dibutyl phthalate solvent by using ethanol to obtain a bottom layer of the waterproof and breathable functional layer; absorbing the waterproof breathable functional layer spinning solution with the mass concentration of 15% into a syringe needle tube, spinning the spinning solution on the upper surface of the waterproof breathable functional layer bottom layer by adopting an electrostatic spinning method (the voltage is 30kV, and the distance between a needle point and the waterproof breathable functional layer bottom layer is 15 cm), cooling by air, and extracting a dibutyl phthalate solvent by using ethanol to obtain a waterproof breathable functional layer film;
s3, heat setting the waterproof and breathable functional layer film at 140 ℃ to obtain the waterproof and breathable film with the gradient pore structure. The average breaking tensile strength of the film was 85N, and the evaporated moisture permeability was 143kg/m 2 D (70 ℃), water pressure resistance of 0.5MPa, permeation flux of 6.64L/m 2 H (70 ℃,3% aqueous NaCl solution), a salt cut of 99.8% (70 ℃,3% aqueous NaCl solution), a porosity of 64.2%, and a contact angle of 137.9 °.
Example 2
1) Preparing a microporous membrane spinning solution: 1.2g of polysulfone and 8.8gN, N-dimethylacetamide are mixed, stirred and dissolved at 50 ℃, and are filtered and defoamed to prepare polysulfone spinning solution with the mass concentration of 12 percent; 1.5g of polysulfone and 8.5g of N, N-dimethylacetamide are mixed, stirred and dissolved at the temperature of 50 ℃, and are filtered and defoamed to prepare polysulfone spinning solution with the mass concentration of 15 percent; 1.8g of polysulfone and 8.2gN, N-dimethylacetamide are mixed, stirred and dissolved at the temperature of 60 ℃, and the mixture is filtered and defoamed to prepare polysulfone spinning solution with the mass concentration of 18 percent;
2) Preparing a microporous membrane: absorbing polysulfone spinning solution with the mass concentration of 18% into a needle tube of an injector, and spinning the spinning solution on a collecting plate by adopting an electrostatic spinning method (the voltage is 20kV, and the distance between a needle point and the collecting plate is 20 cm) to prepare a bottom layer of a supporting layer; then, absorbing 15% mass concentration polysulfone spinning solution into a syringe needle tube, and spinning the spinning solution on the upper surface of the bottom layer of the support layer by adopting an electrostatic spinning method (the voltage is 10kV, and the distance between the needle point and the bottom layer of the support layer is 15 cm) to obtain a middle layer of the support layer; then sucking the polysulfone spinning solution with the mass concentration of 12% into a syringe needle tube, and spinning the spinning solution on the upper surface of the middle layer of the supporting layer by adopting an electrostatic spinning method (the voltage is 15kV, and the distance between a needle point and the middle layer of the supporting layer is 10 cm) to prepare a microporous membrane (namely the supporting layer);
3) Preparing a spinning solution of a waterproof and breathable functional layer: weighing 2g of ETFE and 8g of dioctyl adipate, mixing, stirring and dissolving at 230 ℃, filtering and defoaming to prepare a waterproof and breathable functional layer spinning solution with the mass concentration of 20%; weighing 2.5g of ETFE and 7.5g of dioctyl adipate, mixing, stirring and dissolving at 250 ℃, filtering and defoaming to prepare a waterproof breathable functional layer spinning solution with the mass concentration of 25%;
4) Preparing a waterproof breathable functional layer: sucking 25% mass concentration spinning solution of the waterproof breathable functional layer into a syringe needle tube, spinning the spinning solution on the upper surface of the microporous film by adopting an electrostatic spinning method (the voltage is 30kV, the distance between a needle point and the microporous film is 30 cm), cooling by air, and extracting dioctyl adipate solvent by trichloroethylene to prepare a bottom layer of the waterproof breathable functional layer; absorbing the waterproof breathable functional layer spinning solution with the mass concentration of 20% into a syringe needle tube, spinning the spinning solution on the upper surface of the waterproof breathable functional layer bottom layer by adopting an electrostatic spinning method (the voltage is 25kV, and the distance between a needle point and the waterproof breathable functional layer bottom layer is 20 cm), cooling by air, and extracting a dioctyl adipate solvent by trichloroethylene to obtain a waterproof breathable functional layer film;
5) And (3) performing heat setting on the waterproof and breathable functional layer film at 160 ℃ to obtain the waterproof and breathable film with the gradient pore structure. The average breaking tensile strength of the film was 90N, and the vapor permeability was 135kg/m 2 D (70 ℃), a water pressure resistance of 0.6MPa, a permeation flux of 5.88L/m 2 H (70 ℃,3% aqueous NaCl solution), a salt cut of 99.82% (70 ℃,3% aqueous NaCl solution), a porosity of 63.5%, a contact angle of 150.9 °.
Example 3
1) Melting a polypropylene slicing raw material in a screw extruder at 200 ℃, extruding the raw material into melt trickle by a spinneret plate at 280 ℃, stretching and cooling the melt trickle, and preparing a polypropylene microporous membrane by a flat screen type receiving device;
2) Preparing a spinning solution of a waterproof and breathable functional layer: mixing 2g of ECTFE and 8g of glyceryl triacetate at 280 ℃, stirring, dissolving, filtering and defoaming to prepare a waterproof and breathable functional layer spinning solution with the mass concentration of 20%; mixing 2.2g of ECTFE and 7.8g of glycerol triacetate at 290 ℃, stirring, dissolving, filtering and defoaming to prepare a waterproof breathable functional layer spinning solution with the mass concentration of 22%; mixing 2.5g of ECTFE and 7.5g of glycerol triacetate at 300 ℃, stirring, dissolving, filtering and defoaming to prepare a waterproof breathable functional layer spinning solution with the mass concentration of 25%;
3) Preparing a waterproof and breathable functional layer: sucking 25% by mass of waterproof breathable functional layer spinning solution into a syringe needle tube, spinning the spinning solution on the surface of a polypropylene microporous membrane by adopting an electrostatic spinning method (the voltage is 30kV, the distance between a needle point and the polypropylene microporous membrane is 10 cm), cooling by air, and extracting a glycerol triacetate solvent by acetone to obtain a waterproof breathable functional layer bottom layer; absorbing the spinning solution with the mass concentration of 22% of the waterproof and breathable functional layer into a syringe needle tube, spinning the spinning solution on the upper surface of the bottom layer of the waterproof and breathable functional layer by adopting an electrostatic spinning method (the voltage is 20kV, and the distance between a needle point and the bottom layer of the waterproof and breathable functional layer is 15 cm), cooling by air, and extracting a glycerol triacetate solvent by acetone to prepare a waterproof and breathable functional layer middle layer; then absorbing the waterproof breathable functional layer spinning solution with the mass concentration of 20% into a syringe needle tube, spinning the spinning solution on the upper surface of the waterproof breathable functional layer intermediate layer by adopting an electrostatic spinning method (the voltage is 15kV, and the distance between a needle point and the waterproof breathable functional layer intermediate layer is 20 cm), cooling by air, and extracting a glycerol triacetate solvent by acetone to obtain a waterproof breathable functional layer membrane;
4) And (3) performing heat setting on the waterproof and breathable functional layer film at 240 ℃ to obtain the waterproof and breathable film with the gradient pore structure. The average tensile strength at break of the film was 92N, and the vapor permeability was 138kg/m 2 D (70 ℃), a water pressure resistance of 0.65MPa, a permeation flux of 5.64L/m 2 H (70 ℃,3% aqueous NaCl solution), a salt cut of 99.89% (70 ℃,3% aqueous NaCl solution), a porosity of 61.2%, and a contact angle of 158.2 °.
Example 4
1) Preparing a spinning solution: mixing, stirring and dissolving 1g of polyvinylidene fluoride and 9gN, N-dimethylformamide at 50 ℃, and filtering and defoaming to prepare a polyvinylidene fluoride spinning solution with the mass concentration of 10%; mixing 1.5g of polyvinylidene fluoride and 8.5g of N, N-dimethylformamide at 60 ℃, stirring, dissolving, filtering and defoaming to prepare a polyvinylidene fluoride spinning solution with the mass concentration of 15%; mixing 2g of polyvinylidene fluoride and 8gN, N-dimethylformamide at 70 ℃, stirring, dissolving, filtering and defoaming to prepare polyvinylidene fluoride spinning solution with the mass concentration of 20%; 2.2g of polyvinylidene fluoride and 7.8gN, N-dimethylformamide are mixed, stirred and dissolved at the temperature of 80 ℃, and the polyvinylidene fluoride spinning solution with the mass concentration of 22 percent is prepared through filtration and defoaming.
2) Preparing a waterproof breathable functional layer: absorbing polyvinylidene fluoride spinning solution with the mass concentration of 22% into a needle tube of an injector, and spinning the spinning solution on a collecting plate by adopting an electrostatic spinning method (the voltage is 20kV, and the distance between a needle point and the collecting plate is 20 cm) to prepare a waterproof and breathable functional layer bottom layer; absorbing polyvinylidene fluoride spinning solution with the mass concentration of 20% into a syringe needle tube, and spinning the spinning solution on the upper surface of the bottom layer of the waterproof and breathable functional layer by adopting an electrostatic spinning method (the voltage is 15kV, and the distance between a needle point and the bottom layer of the waterproof and breathable functional layer is 15 cm) to obtain a middle layer of the waterproof and breathable functional layer; then absorbing polyvinylidene fluoride spinning solution with the mass concentration of 15% into a syringe needle tube, and spinning the spinning solution on the upper surface of the waterproof breathable functional layer middle layer by adopting an electrostatic spinning method (the voltage is 15kV, and the distance between a needle point and the waterproof breathable functional layer middle layer is 12 cm) to obtain a waterproof breathable functional layer lower layer; finally, absorbing the polyvinylidene fluoride spinning solution with the mass concentration of 10% into a syringe needle tube, and spinning the spinning solution on the upper surface of the lower layer of the waterproof and breathable functional layer by adopting an electrostatic spinning method (the voltage is 10kV, and the distance between a needle point and the lower layer of the waterproof and breathable functional layer is 10 cm) to obtain a waterproof and breathable functional layer film;
3) And (3) performing heat setting on the waterproof and breathable functional layer film at 160 ℃ to obtain the waterproof and breathable film with the gradient pore structure. The average tensile strength at break of the film was 89N, and the vapor permeability was 140kg/m 2 D (70 ℃), a water pressure resistance of 0.4MPa, a permeation flux of 6.51L/m 2 H (70 ℃,3% aqueous NaCl solution), a salt cut of 99.74% (70 ℃,3% aqueous NaCl solution), a porosity of 66.8%, and a contact angle of 135.4 °.
Claims (10)
1. The waterproof breathable film with the gradient pore structure is characterized by comprising a supporting layer and a waterproof breathable functional layer, wherein the waterproof breathable functional layer is spun on the surface of the supporting layer by an electrostatic spinning method; the aperture of the waterproof breathable film from the supporting layer to the waterproof breathable functional layer is gradually reduced.
2. A method for preparing the waterproof breathable film having a gradient pore structure according to claim 1, comprising the steps of:
s1, preparing a spinning solution of a waterproof and breathable functional layer: at the temperature of 50-300 ℃, the mass concentration is 10-30: 70-90 fluorine-containing polymer material and solvent are mixed, stirred and dissolved, and then the mixture is prepared after filtration and defoaming;
s2, preparing a waterproof and breathable functional layer: spinning the waterproof breathable functional layer spinning solution on the supporting layer by adopting an electrostatic spinning method;
s3, preparing a waterproof breathable film: the waterproof breathable functional layer/supporting layer is prepared by heat setting.
3. The method according to claim 2, wherein the fluoropolymer in step S1 is PVDF/hexafluoropropylene copolymer, PTFE, ETFE or ECTFE; the solvent is one of N, N-dimethylformamide, N-dimethylacetamide, dibutyl phthalate, diethyl phthalate, dioctyl sebacate, dibutyl sebacate, dioctyl adipate, glycerol triacetate, sulfolane and gamma-butyrolactone; the voltage of the electrostatic spinning in the step S2 is 10-40 kV; preferably, the voltage of the electrostatic spinning is 15-30 kV; in the step S2, the supporting layer is a non-woven fabric or a microporous membrane; the heat setting temperature in the step S3 is 140-250 ℃.
4. The preparation method according to claim 3, wherein the non-woven fabric is made of PP or PET; the microporous membrane is prepared by a melt spinning method or an electrostatic spinning method.
5. The preparation method of claim 4, wherein the melt spinning method for preparing the microporous membrane specifically comprises the following steps: melting thermoplastic slice resin in a screw extruder, extruding into melt trickle by a spinneret plate, stretching, cooling and obtaining the thermoplastic slice resin by a flat screen type receiving device.
6. The method according to claim 5, wherein the thermoplastic resin chip is one of polypropylene, polyvinyl chloride, polyvinylidene fluoride, polyester, polyamide, polyethylene, polytetrafluoroethylene, polycarbonate, polyacrylonitrile, polytetramethylene terephthalate, or polystyrene; the melting temperature is 100-350 ℃; the extrusion temperature is 200-400 ℃.
7. The method of claim 4, wherein the electrospinning method for preparing the microporous membrane comprises the steps of:
s1, at the temperature of 50-90 ℃, mixing the components with the mass concentration of 12-30: 70-82, mixing, stirring and dissolving the macromolecular film-forming material and a solvent, and filtering and defoaming the mixture to obtain spinning solution;
and S2, spinning the spinning solution into a microporous membrane by adopting an electrostatic spinning method.
8. The preparation method according to claim 7, wherein the polymer film forming material in step S1 is one of polyvinylidene fluoride, polysulfone, polyethersulfone, polyvinyl chloride and polyacrylonitrile; in the step S1, the solvent is one of N, N-dimethylformamide, N-dimethylacetamide, dimethyl sulfoxide, N-methylpyrrolidone and triethyl phosphate; the voltage of the electrostatic spinning in the step S2 is 10-40 kV; preferably, the voltage of the electrostatic spinning is 15 to 30kV.
9. The preparation method according to claim 2, wherein in the step S1, the waterproof and breathable functional layer spinning solution with different mass concentrations is prepared, and the waterproof and breathable functional layer spinning solution is spun on the support layer by layer according to the sequence from high mass concentration to low mass concentration by an electrospinning method.
10. Use of the waterproof breathable film of any one of claims 1 to 9 in sewage treatment.
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