CN1272093C - Method for preparing polyvinylidene fluoride flat plate microporous compound film - Google Patents
Method for preparing polyvinylidene fluoride flat plate microporous compound film Download PDFInfo
- Publication number
- CN1272093C CN1272093C CN 200410067170 CN200410067170A CN1272093C CN 1272093 C CN1272093 C CN 1272093C CN 200410067170 CN200410067170 CN 200410067170 CN 200410067170 A CN200410067170 A CN 200410067170A CN 1272093 C CN1272093 C CN 1272093C
- Authority
- CN
- China
- Prior art keywords
- film
- preparation
- compound film
- polyvinylidene fluoride
- liquid
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Abstract
The present invention discloses a preparation method for polyvinylidene fluoride flat-plate microporous compound films. A supporting layer is arranged on a compound film scraping machine, and the running and distribution speed of the supporting layer on a line speed controller is regulated. The cutting edge thickness (liquid film thickness) between a scraper and the supporting layer is regulated by a plug gauge. Film preparation liquid is poured in a feed chute of the film scraping machine, and the liquid enters a cutting edge chute through a measuring pump and a filter. The machine is started, and the supporting layer runs; the solution is coated on the supporting layer; after the primary compound film runs for a period of time in the air, the film is immersed in a coagulating bath with a certain temperature, and a PVDF/supporting-layer compound film is formed. The present invention is characterized in that a flat-plate PVDF microporous compound film with a large pore diameter, high intensity and a high water flux is prepared by regulating the formulation of film preparation liquid and the film preparation technology. Measurements show that the pore diameter of a product obtained by the present invention is from 0.1 to 1.5 mum; the penetrating flux of pure water is from 400 to 2100 L/h. m (0.1MPa); the film thickness is from 150 to 220 mum; the radial tensile strength of the film is 35.2MPa, and the breaking elongation rate is 51.92%; the transverse tensile strength is 18.2MPa and the breaking elongation rate is 68.7.
Description
Technical field
The present invention relates to a kind of preparation method of polyvinylidene fluoride flat plate microporous compound film.
Background technology
Kynoar is the fluorine-containing multifunctional material that is obtained by vinylidene fluoride monomers homopolymerization or copolymerization, is linear crystalline polymer, and its degree of crystallinity is generally between 55～80%.Because the binding energy height of fluorocarbon chain, have good heat-resisting, decay resistance, the temperature range that is suitable for is-40～150 ℃, the corrosion and the swelling of energy antioxidant, acid, alkali, salt and halogen, aromatic hydrocarbons, aliphatic hydrocarbon and chlorinated solvent, have excellent uvioresistant and ageing-resistant performance, and have characteristics such as nonpolar, antipollution.Particularly this material can be dissolved in dimethyl sulfoxide (DMSO), N, dinethylformamide, N, N-dimethylacetylamide, N-methyl pyrrolidone are configured to polymer solution in the various polarity solvents such as triethyl phosphate, tetramethylurea, be fit to very much immersion precipitation inversion of phases legal system film.Made film has two kinds of configurations: flat sheet membrane and hollow-fibre membrane.
To the latter stage nineties, the PVDF flat sheet membrane mainly is a homogeneous membrane from the mid-80 exploitation PVDF flat sheet membrane.As U.S.Pat.No.4,384,047 adopt immersion precipitation to prepare the PVDF milipore filter, and the film average pore size is 1-100nm, water flux 6-120L/m
2H (0.2Mpa).U.S.Pat.No.4,203,847 and U.S.Pat.No.4,203,848 adopt immersion precipitation to prepare homogeneous PVDF perforated membrane, and the quantity-produced technical process is disclosed, the thickness of the film of this patent disclosure is about 90～120 μ m, and solvent is an acetone, and coagulating bath is the aqueous solution of 5-80% (v/v) acetone, complex process, the cost height; U.S.Pat.No.6,146,747 and U.S.Pat.No.6,110,309 have improved a kind of preparation film and non-homogeneous symmetric membrane symmetrically, and the aperture is at 0.01～3.0 μ m, thickness is 25～30 μ m, and the aperture of upper surface is less than the lower surface aperture, but film strength is very low, can only once use being lower than 0.07Mpa; U.S.Pat.No.6,013,688 provide a kind of method for making and product of PVDF perforated membrane, solvent is a miscible agent, and isopropyl alcohol, methyl alcohol or ethanol have been adopted in coagulating bath, and cost of manufacture is higher, the performance of gained film is as follows: thickness is about 120 μ m, membrane aperture 0.018～6 μ m, working pressure is at 0.055～0.07Mpa, and it is not enough as seen to change film strength; Sasaki adopts immersion precipitation to prepare the asymmetric perforated membrane of PVDF, at process aspect mainly is the structure that the size of non-solvent vapour pressure in temperature by the aerial evaporation time of film of regulating and control to come into being, when evaporation and the air is come controlling diaphragm, the characteristics of gained film are that one deck structure of minimum-value aperture in the film is in the place from upper surface 1～30 μ m, thickness is 100～115 μ m, and also there are the low characteristics of intensity in this film.By above preparation PVDF homogeneous membrane patent as can be seen, PVDF homogeneous membrane intensity is low, and the pressure that bears during application is little, and film is thicker, and these two make film flux is little in actual applications, and the process resistance is big; And the complicated process of preparation of above patent, coagulating bath all are the mixtures of solvent/non-solvent, and production cost is higher.Therefore study the large aperture, pvdf membrane thin, that intensity is big has very important and practical meanings.At above problem, the PVDF composite membrane becomes the research focus in recent years.U.S.Pat.No.5,376,273 have described the preparation of PVDF/PVDF fabric composite membrane and the performance of product, employed solvent is N, N-dimethylacetylamide, N-methyl pyrrolidone, used little molecule cosolvent formic acid, coagulating bath is a methyl alcohol, film average pore size 0.02～2 μ m.This composite membrane has greatly improved film strength, is convenient to make membrane module, but the hydrophobicity of film is very strong, and coagulating bath is a methyl alcohol, and methyl alcohol easily volatilization makes that manufacturing process toxicity is big, and supporting layer is the PVDF fabric, and this has increased production cost.
Summary of the invention
The preparation method who the purpose of this invention is to provide the polyvinylidene fluoride flat plate microporous compound film of the simple and low production cost of a kind of technical process.Composite membrane had both solved the problem of intensity, also can significantly increase the average pore size of film.In the multiple industrial circles such as this film can be widely used in biochemistry, food, medical treatment, brews alcoholic beverages, purification, wastewater treatment.
The step of method is:
1) Kynoar, additive, non-solvent are dissolved in the organic solvent, heating stirs, and filters, and obtains the preparation liquid that Kynoar concentration is 8～14wt% after the vacuum defoamation, set aside for use, additive is: polyvinylpyrrolidone K30 or Macrogol 6000;
2) be that 25～65 ℃ preparation liquid is coated on the supporter of nonwoven or woven dacron by knifing machine with temperature range, regulate the edge of a knife of knifing machine and the thickness that the distance between the supporter is controlled knifing, scraping film thickness is 100～200 μ m, and the cloth speed of walking of supporting layer is 1.0m/min or 1.5m/min;
3) supporter that will be coated with preparation liquid is exposed in the air, and the sky time of exposing to the sun is 5～25s;
4) supporter that is coated with preparation liquid after sky is exposed to the sun immerses in the coagulating bath, forms microporous compound film, and coagulation bath temperature is 0～25 ℃;
5) microporous compound film that forms was soaked in deionized water 6～9 days, then microporous compound film is dipped in the glycerine water solution of 15～20% (v/v) and carries out hydrophilicity-imparting treatment, the processing time
Advantage of the present invention is:
1) simple, the serialization of preparation process, industrialization easily.
2) coagulating bath consist of common non-solvent pure water, the temperature of coagulating bath is at 10～25 ℃ in addition, easy control of temperature, and saved the needed energy consumption of high temperature coagulating bath; This two-phase has significantly reduced production cost;
3) existence of supporting layer, make the compound film strength of gained improve greatly, hot strength is 26.7Mpa, elongation at break is 60.31%, the hot strength of homogeneous pvdf membrane has only 0.925MPa, elongation at break is 36.05%, and the hot strength of composite membrane is 28.7 times of homogeneous membrane intensity, and elongation at break is 1.67 times of homogeneous membrane;
4) supporting layer improves film strength greatly, so the top layer polyvinylidene fluoride film can apply extremely thinly, at 30～80 μ m, the aperture is 0.1～1.5 μ m, the aperture is big, narrowly distributing, and because supporting layer can not cause resistance to filter process in microfiltration applications, therefore, the PVDF homogeneous flat sheet membrane before the resistance ratios that this composite membrane forms filter process in microfiltration process is much smaller.
Description of drawings
Fig. 1 is a technical process schematic diagram of producing Kynoar micropore flat composite membrane continuously;
Fig. 2 be the prepared composite membrane surface of different Kynoar preparation liquid concentration the SEM photo (A:8wt%, B:10wt%, C:12wt%, D:14wt%);
Fig. 3 is the surperficial SEM photo that makes composite membrane under the different coagulation bath temperatures (A:10 a ℃, B:18 ℃, C:25 ℃);
Fig. 4 is the SEM photo (A: lithium chloride, B: Macrogol 6000, C: polyvinylpyrrolidone K30) that contains the configuration of surface of different additive film;
Fig. 5 be different polyvinylpyrrolidone content composite membranes configuration of surface SEM photo (A:0wt%, B:2wt%, C:5wt%, D:7wt%);
Fig. 6 be the composite membrane configuration of surface SEM photo that obtains the different sky times of exposing to the sun (A:5s, B:15s, C:25s);
The preparation liquid temperature SEM photo of composite membrane configuration of surface (A:35 ℃, B:45 ℃, C:55 ℃, D:65 ℃) simultaneously not when Fig. 7 is knifing.
The specific embodiment
The present invention with a certain proportion of Kynoar, additive and solvent about 70 ℃ in flask abundant stirring and dissolving, dissolve fully to Kynoar, solution keeps clarification, the time is generally 48h.The solution of said method preparation is filtered with Buchner funnel, carry out vacuum defoamation a few hours, set aside for use then.
Supporting layer is installed on compound knifing machine, walk cloth speed by what regulate that the linear speed controller regulates supporting layer; Mix up edge of a knife thickness (thickness of liquid film) between scraper and the supporting layer with feeler gauge, edge of a knife thickness is 100～200 μ m, and optimum value is 150 μ m; In the preparation liquid feed well of falling the knifing machine, through measuring pump, filter, enter in the edge of a knife groove, start, the supporting layer operation, solution is coated with to be scraped on the supporting layer, and nascent composite membrane moves a period of time in air, be immersed in the coagulating bath of uniform temperature PVDF solution freezing film on supporting layer subsequently.The composite membrane of scraping was soaked in deionized water 6～9 days, make fully exchange of solvent and non-solvent (water).Then film is carried out post processing, wet film is soaked 24h in 15～20% glycerine water solution, natural then airing (Fig. 1).
Kynoar used herein is a Shanghai 3F new material limited company, and model is FR904, molecular weight: Mn=475637, Mw=2092027, d=4.398372.The degree of crystallinity of PVDF raw material is 33%, belong to semicrystalline polymeric, liquid-solid phase-splitting also can take place in solution system except common liquid liquid phase process takes place when adopting immersion precipitation inversion of phases legal system film, can observe crystal structure in the structure of prepared telolemma.Condition during according to film forming, the phase-splitting branch of crystalline polymer has three kinds of situations, and a kind of is to have crossed the crystallization line, liquid-liquid phase-splitting takes place, and crystallization still took place in the phase-splitting later stage, and this is instantaneous phase-splitting, identical with the instantaneous liquid-liquid phase-splitting of amorphous polymer, phase-splitting mechanism is nucleating growth; Another is exactly that liquid-solid phase-splitting (crystallization) takes place earlier, and liquid-liquid phase-splitting takes place again; Also having a kind of is that liquid-liquid phase-splitting and liquid-solid phase-splitting take place simultaneously, and back two kinds is the time-delay phase-splitting, is a very slow process because liquid-solid phase-splitting is a crystallization.The structure of these three kinds of formed films of branch phase behavior also respectively has characteristics.The film that first kind of phase-splitting forms and the instantaneous liquid of amorphous polymer-the formed membrane structure of liquid phase-splitting is similar, is asymmetric membrane has dense layer surface and column macroporous structure, and spongelike structure.Second kind of formed film of phase-splitting do not have fine and close cortex, and the surface of film is made up of the spheric granules that equidimension closely links to each other mutually, and the cross section also is made up of spherocrystal, and spongelike structure is not clearly.The film that forms under the third phase-splitting situation, the surface is made up of spheric granules, but the size of particle obviously than under second kind of situation greatly, the cross section is the spongelike structure of even porous, spongy hole is an open bore, and connects mutually, and polymeric matrix is that the spherolite of the equidimension of distortion is formed.These three kinds of structures have all occurred in this invention.
The content of Kynoar in preparation liquid is generally 8～14% (wt), is preferably 10～12% (wt), and when Kynoar concentration was lower than 8% (wt), preparation liquid concentration was low excessively, because the knifing thinner thickness, therefore resulting composite membrane is easy to generate defective; When concentration was higher than 14% (wt), preparation liquid viscosity was bigger, and generally speaking, resin content original text in the preparation liquid can make pore-foaming agent content reduce, and these all make the gained membrane porosity reduce, and are difficult to obtain the composite membrane of larger aperture.Polymer concentration is a key factor that influences membrane structure form and performance.Increase with concentration, thickness increases, water flux reduces gradually, the average pore size on surface reduces, according to thermodynamic principles, after preparation liquid immerses coagulation bath, solvent and non-solvent will be bathed the interface by system membrane polymer solution/gel and be spread mutually, and cause polymer solution generation liquid-liquid phase-splitting, along with the increase of polymer concentration in the preparation liquid, the liquid-liquid phase-splitting of polymer-poor phase nucleation will take place in system and since polymer stingy in formed nucleus increase, and under the promotion of concentration gradient, constantly increase, up to around rich in polymers continuous phase till gelation is solidified, slough the formed network structure of these nucleus densification more behind the solvent, the aperture that shows as film diminishes, the hole proportion reduces, and the porosity of film reduces; On the other hand, increase along with PVDF concentration in the preparation liquid, solution viscosity also increases thereupon, thereby solvent in the preparation liquid and the non-solvent dynamics exchange process in the coagulating bath are obviously slowed down, the feasible delay behavior that is separated is more obvious, suppresses finger-like pore and generates, and the film superficial layer of generation is finer and close, water flux reduce (example 1, Fig. 2).
Among the present invention, be N as the employed solvent of preparation liquid, the N-dimethylacetylamide, N, dinethylformamide, N-methyl pyrrolidone, dimethyl sulfoxide (DMSO), triethyl phosphate, total addition of solvent is: 71～87% (wt).
Among the present invention, can add 0～7% pore additive in the preparation liquid, on the principle, additive has three aspects to the influence of membrane structure: the one, because the solvability of different additives and solvent is different, the dissolved state of Kynoar strand in solution there is different influences; The 2nd, the adding of additive has also had influence on the chemical potential of solvent, and then the mutual exchange velocity of solvent and non-solvent in the gel process of impact polymer in non-solvent, has changed the structure of film; The 3rd, water miscible additive is also very easy being dissolved in the non-solvent water in gel process, stays the space after making film solidify, and improved the degree of communication between the micropore fenestra and the porosity of film.This paper uses two class additives, and a class is hydrophilic polyvinylpyrrolidone and two kinds of polymer of polyethylene glycol, and another kind of is the inorganic molecules lithium chloride.With respect to the micromolecule additive lithium chloride, water flux with the polyvinylidene fluoride microporous film of hydrophilic additive polyvinylpyrrolidone and polyethylene glycol preparation wants big, average pore size and thickness reduce according to the order of adding polyvinylpyrrolidone, polyethylene glycol, lithium chloride, three's surface contact angle also is this to be increased in proper order, shows that making additive with hydrophilic polymers can effectively improve the hydrophily on film surface.Analyze reason, lithium chloride is the very strong little molecule of hydrophily, can fast speeds being solidified bath water displacement (dissolving) from nascent film in the solidification stages of film comes out, and when select polyvinylpyrrolidone for use, when polyethylene glycol is additive, because both strands are longer, stronger with the effect of Kynoar chain, being difficult for being solidified bath water in the solidification stages of film cements out, may partly can remain in the microporous barrier after solidifying, therefore its to the hydrophilic effect of polyvinylidene fluoride microporous film may be more obvious (example 4, Fig. 4).On the other hand, but when polyvinylpyrrolidone content from 0% to 7% increases, polyvinylpyrrolidone shared volume in preparation liquid is big more, it is many more that migration is come out, final formed membrane structure is more and more loose, macropore and finger-like pore are more and more, and the aperture of film surface holes also shows the trend of increase, and the hole count of surface unit area increases.The second, as can be seen, when polyvinylpyrrolidone content was increased to 7%, water flux and average pore size were that 5% film that makes is to have reduced with respect to polyvinylpyrrolidone content.This may be because under the same situation of filming technology, the concentration of the preparation liquid of 7% polyvinylpyrrolidone content is bigger, in solvent and non-solvent exchange diffusion process, it is fewer that migration is come out, and in follow-up vacuolar membrane technology, the time of vacuolar membrane and the film of other content too, even the amount of moving out of polyvinylpyrrolidone is identical with other film during this period, but the residual quantity of polyvinylpyrrolidone is obviously greater than other film in the film of 7% polyvinylpyrrolidone.Owing to above two reasons, thus polyvinylpyrrolidone content is 7% telolemma show average pore size and water flux all reduce (example 5, Fig. 5), so the consumption optimum value of pore additive is about 5 ± 0.5%.For the selection of polymeric additive molecular weight, increase with molecular weight, the water flux of gained composite membrane increases, and in the polyethylene glycol series additive, Macrogol 6000 is best selection.
Among the present invention, the non-solvent that adds in the preparation liquid is the composition of coagulating bath: deionized water.Here water also can be regarded as a kind of pore-foaming agent, in addition, the concentration that improves non-solvent water in the preparation liquid is the same with improving polymer concentration with the effect that reduces temperature, make the liquid-solid phase-splitting of system generation crystallization, obtain the membrane structure of solidifying at last by crystallization, the surface that shows as film is made up of many spherolite dress particles, and, increase average pore size with water content in the preparation liquid increases to some extent, this is owing to the water on nascent film surface and solidifies the easier exchange of bath water, this moment, surface water shared space structure solidified to get off faster, the aperture during compared with solvent and water exchange formed aperture big.
Among the present invention, the temperature of preparation liquid is controlled at 25 ℃, 35 ℃, 45 ℃, 55 ℃ and 65 ℃ respectively during knifing.Rising along with the preparation liquid temperature, crystallization alignment polymer-non-solvent axle moves, this explanation raises with temperature, on the one hand if liquid-solid phase-splitting (crystallization) takes place, just needs more polymer and non-solvent, on the other hand, temperature raises, and the speed of solvent and non-solvent exchange improves, and dominant liquid-solid phase-splitting dies down gradually, system is more and more tended to liquid-liquid phase-splitting, and the aperture and the number in the hole that the surface generates all can increase (example 8).
Among the present invention, coagulating bath consist of deionized water, this greatly reduces the production cost of Kynoar micropore flat composite membrane, and the temperature of coagulating bath has been selected 10 ℃, 18 ℃ and 25 ℃, and coagulation bath temperature is similar to the preparation liquid Temperature Influence with Effect on Performance to membrane structure.The crystalline polymer film forming procedure also exists instantaneous phase-splitting and time-delay phase-splitting, and still, instantaneous phase-splitting and time-delay phase-splitting are determined by the result that liquid-solid phase-splitting of crystallization and the phase-splitting of liquid liquid are competed.Rising along with temperature, the water flux of microporous barrier and surperficial average pore size all increase to some extent, reason may be when the temperature of coagulating bath raises, the activity of solvent and non-solvent strengthens, the exchange velocity of solvent and non-solvent was accelerated when preparation liquid was separated, the phase-splitting of instantaneous liquid liquid takes place, and has caused the formation of loose pore structure, so the water flux of microporous barrier and all increases to some extent of average pore size.When temperature was low, solvent and non-solvent exchange velocity reduced, and the time-delay phase-splitting takes place, and helped that the PVDF crystal forms in the preparation liquid, and phase-splitting mainly is made owing to the liquid-solid phase-splitting of crystallization, and it is less that formed film contains macropore, be mainly spongelike structure (example 3, Fig. 3).
Among the present invention, when adopting immersion precipitation to send out the system film, the time of the nascent membrane air walk that scrapes, promptly the sky time of exposing to the sun is respectively 5s, 15s, 25s, and three kinds of sky times of exposing to the sun are not very big to membrane structure and Effect on Performance.
Among the present invention, for making in the application afterwards of prepared PVDF micropore flat composite membrane, especially easier when handling the aqueous solution, so the film to gained carries out hydrophilicity-imparting treatment, be about to composite membrane and in the glycerine water solution of 15% (v/v), soak about 24h, allow and all adsorb glycerol molecule in the surperficial and hole of PVDF micropore flat composite membrane.
Following embodiment is done more detailed description to the present invention, but described embodiment is not construed as limiting the invention.
Embodiment 1
Preparation liquid concentration is to dull and stereotyped composite microporous membrane structure of PVDF and Effect on Performance
Ratio is respectively the Kynoar/polyvinylpyrrolidone/N of 8/5/87,10/5/85,12/5/83,14/5/81 (wt%), the N-dimethylacetylamide about 70 ℃ in flask abundant stirring and dissolving 48h, dissolve fully to polymer, solution keeps clarification; Above-mentioned preparation liquid is filtered with Buchner funnel, carry out vacuum defoamation a few hours, set aside for use then.The PET nonwoven is installed on compound knifing machine, and the cloth speed of walking of regulating linear speed controller control nonwoven is 1.5m/s; With; Mix up edge of a knife thickness 150 μ m between scraper and the supporting layer with feeler gauge; 14.5 ℃ of environment temperatures are that 25 ℃ preparation liquid is poured in the hopper with temperature, carry out knifing then, solution is coated with to be scraped on the supporting layer, moves 5s in air, is immersed in subsequently in 18 ℃ the coagulating bath, coagulating bath is a deionized water, the very fast freezing film of polymer solution.Room temperature during knifing is 16 ℃, and humidity is controlled at 80%.The composite membrane of scraping was soaked in deionized water about 7 days; Then film is carried out post processing, wet film is soaked 24h in 15% glycerine water solution, at last with film nature airing.
The clip diameter is 8 centimeters a circular film, puts into SCM-300 type ultrafiltration cup, this film at first under 0.15MPa precompressed 30 minutes basicly stable until water flux, under 0.1MPa, measure then.The configuration of surface of film is by the direct gold-plated back of dry film scanning electron microscopic observation.The thickness of prepared composite membrane, average pore size and water flux see Table 1.The configuration of surface of various films is seen accompanying drawing 2.No. 2 films and the homogeneous membrane that No. 2 films, 1%NaOH solution are soaked 18h have carried out the stretching mechanical experiment on Shimadzu AG-1 type electronic tensile machine, the results are shown in Table 2.
The different PVDF concentration of table 1. are to the Effect on Performance of flat composite membrane
| The film numbering | PVDF concentration wt % | Film surface average pore size μ m | Thickness μ m | Water flux L/h.m 2 (0.1Mpa) |
| 1 | 8 | 1.0-1.5 | 150 | 2035 |
| 2 | 10 | 0.8-1.2 | 172 | 1665 |
| 3 | 12 | 0.6-1.0 | 174 | 1332 |
| 4 | 14 | 0.2-0.4 | 200 | 407 |
Table 2 Mechanical test results
| Film | Hot strength MPa | Elongation at break % |
| No. 2 films | 26.70 | 60.31 |
| No. 2 films of dipping by lye | 26.38 | 58.90 |
| Homogeneous membrane | 0.925 | 36.05 |
Embodiment 2
Supporting layer is to the influence of film properties
The Kynoar of mass ratio 10/5/85, polyvinylpyrrolidone, N, dinethylformamide about 70 ℃ in flask abundant stirring and dissolving 48h, dissolve fully to PVDF, solution keeps clarification; Above-mentioned preparation liquid is filtered with Buchner funnel, carry out vacuum defoamation a few hours, set aside for use then.Use PET nonwoven and terylene to be supporting layer respectively, supporting layer is installed on knifing machine, the cloth speed of walking of regulating linear speed controller control supporting layer is 1.5m/s; Mix up edge of a knife thickness 150 μ m between scraper and the supporting layer with feeler gauge; With temperature is that 25 ℃ of preparation liquids are poured in the hopper, carries out knifing then, and solution is coated with to be scraped on the supporting layer, moves 5s in air, is immersed in subsequently in 26 ℃ the coagulating bath, and coagulating bath is a deionized water, the very fast freezing film of polymer solution.Room temperature during knifing is 28 ℃, and humidity is controlled at 80%.The composite membrane of scraping was soaked in deionized water about 7 days; Then film is carried out post processing, wet film is soaked 24h in 15% glycerine water solution, at last with film nature airing.
The mensuration of water flux and the sign of SEM are with embodiment 1.The thickness of prepared composite membrane, average pore size and water flux see Table 3.
The comparison of the different supporting layer composite membranes of table 3.
| The film numbering | Supporting layer | Film surface average pore size μ m | Thickness μ m | Water flux L/h.m 2 (0.1Mpa) |
| 5 | Terylene | 0.5-0.6 | 186 | 888 |
| 6 | Nonwoven | 0.5-0.7 | 177 | 974 |
Embodiment 3
Coagulation bath temperature is to polyvinylidene fluoride flat structure of composite membrane and Effect on Performance
Preparation liquid preparation is with to scrape membrane process identical with embodiment 1, and being solvent employed is the N-methyl pyrrolidone, 18 ℃ of environment temperatures, and the temperature of coagulating bath is set at 10 ℃, 18 ℃, 25 ℃ respectively in addition, and the mensuration of water flux and the sign of SEM are with embodiment 1.The thickness of prepared composite membrane, average pore size and water flux see Table 4.The configuration of surface of various films is seen accompanying drawing 3.
The PVDF compound slab film properties for preparing under the different coagulation bath condition of table 4. relatively
| The film numbering | Coagulation bath temperature ℃ | Film surface average pore size μ m | Thickness μ m | Water flux L/h.m 2 (0.1Mpa) |
| 7 | 10 | 0.8-1.2 | 174 | 1554 |
| 8 | 18 | 0.8-1.0 | 172 | 1635 |
| 9 | 25 | 1.0-1.2 | 177 | 1690 |
Embodiment 4
Additive types is to membrane structure and Effect on Performance
Mass ratio is 10/5/85 Kynoar, additive, N, the N-dimethylacetylamide about 70 ℃ in flask abundant stirring and dissolving 48h, dissolve fully to PVDF, solution keeps clarification; Above-mentioned preparation liquid is filtered with Buchner funnel, carry out vacuum defoamation a few hours, set aside for use then.Additive is respectively LiCl, Macrogol 6000 (PEG6000) and PVP; The PET nonwoven is installed on compound knifing machine, and the cloth speed of walking of regulating linear speed controller control nonwoven is 1.5m/s; With; Mix up edge of a knife thickness 150 μ m between scraper and the supporting layer with feeler gauge; 26.5 ℃ of environment temperatures are that 25 ℃ preparation liquid is poured in the hopper with temperature, carry out knifing then, solution is coated with to be scraped on the supporting layer, moves 5s in air, is immersed in subsequently in 25 ℃ the coagulating bath, coagulating bath is a deionized water, the very fast freezing film of polymer solution.Room temperature during knifing is 26.5 ℃, and humidity is controlled at 80%.The composite membrane of scraping was soaked in deionized water about 7 days; Then film is carried out post processing, wet film is soaked 24h in 15% glycerine water solution, at last with film nature airing.
The mensuration of water flux and the sign of SEM are with embodiment 1.The thickness of prepared composite membrane, average pore size and water flux see Table 5.The configuration of surface of various films is seen accompanying drawing 4.The measurement of contact angle is as follows, and the PVDF flat sheet membrane that drying is handled freeze-day with constant temperature 4 hours in 80 ℃ of baking ovens is measured contact angle with a method of lying with three-stage distillation water then on KR SS DSA 10 MK2 type contact angle instruments.Each sample is surveyed and is averaged for 8 times.
Table 5. different additive is to the Effect on Performance of PVDF composite membrane
| The film numbering | Additive | Contact angle | Film surface average pore size μ m | Thickness μ m | Water flux L/h.m 2 (Mpa) |
| 10 | LiCl | 86.40 | 0.2-0.4 | 180 | 481 |
| 11 | PEG6000 | 85.67 | 0.2-0.6 | 186 | 574 |
| 12 | PVP (K30) | 80.27 | 0.5-1.2 | 191 | 1294 |
Embodiment 5
The different additive consumption is to membrane structure and Effect on Performance
Mass ratio is respectively 10/0/90,10/2/88,10/5/85,10/7/83 Kynoar, polyvinylpyrrolidone, N, the N-dimethylacetylamide about 70 ℃ in flask separately abundant stirring and dissolving 48h, dissolve fully to PVDF, solution keeps clarification; Above-mentioned each preparation liquid is filtered with Buchner funnel, carry out vacuum defoamation a few hours, set aside for use then.The PET nonwoven is installed on compound knifing machine, and the cloth speed of walking of regulating linear speed controller control nonwoven is 1.5m/s; Mix up edge of a knife thickness 150 μ m between scraper and the supporting layer with feeler gauge; 26.5 ℃ of environment temperatures are that 25 ℃ preparation liquid is poured in the hopper with temperature, carry out knifing then, solution is coated with to be scraped on the supporting layer, moves 5s in air, is immersed in subsequently in 25 ℃ the coagulating bath, coagulating bath is a deionized water, the very fast freezing film of polymer solution.Room temperature during knifing is 26.5 ℃, and humidity is controlled at 80%.The composite membrane of scraping was soaked in deionized water about 7 days; Then film is carried out post processing, wet film is soaked 24h in 15% glycerine water solution, at last with film nature airing.
The mensuration of water flux and the sign of SEM are with embodiment 1.The thickness of prepared composite membrane, average pore size and water flux see Table 6.The configuration of surface of various films is seen accompanying drawing 5.
Table 6 different additive consumption is to the Effect on Performance of PVDF composite membrane
| The film numbering | PVP content (wt%) | Film surface average pore size μ m | Thickness μ m | Water flux L/h.m 2(MPa) |
| 13 | 0 | 0.1-0.5 | 146 | 75 |
| 14 | 2 | 994 | ||
| 12 | 5 | 0.5-1.2 | 177 | 1294 |
| 15 | 7 | 0.1-0.3 | 187 | 984 |
Embodiment 6
The expose to the sun influence of time of sky
Mass ratio is respectively 10/5/85 Kynoar, polyvinylpyrrolidone, N, the N-dimethylacetylamide about 70 ℃ in flask separately abundant stirring and dissolving 48h, dissolve fully to PVDF, solution keeps clarification; Above-mentioned each preparation liquid is filtered with Buchner funnel, carry out vacuum defoamation a few hours, set aside for use then.The PET nonwoven is installed on compound knifing machine, and the cloth speed of walking of regulating linear speed controller control nonwoven is 1.5m/s; Mix up edge of a knife thickness 150 μ m between scraper and the supporting layer with feeler gauge; 26.5 ℃ of environment temperatures, with temperature is that 25 ℃ preparation liquid is poured in the hopper, carry out knifing then, solution is coated with to be scraped on the supporting layer, the time of moving in air is respectively 5s, 15s and 25s, be immersed in subsequently in 25 ℃ the coagulating bath, coagulating bath is a deionized water, the very fast freezing film of PVDF solution.Room temperature during knifing is 26.5 ℃, and humidity is controlled at 80%.The composite membrane of scraping was soaked in deionized water about 7 days; Then film is carried out post processing, wet film is soaked 24h in 15% glycerine water solution, at last with film nature airing.
The mensuration of water flux and the sign of SEM are with embodiment 1.The thickness of prepared composite membrane, average pore size and water flux see Table 7.The configuration of surface of various films is seen accompanying drawing 6.
The different skies of table 7. Effect on Performance of time of exposing to the sun to the PVDF composite membrane
| The film numbering | The sky time s that exposes to the sun | Film surface average pore size μ m | Thickness μ m | Water flux L/h.m 2(MPa) |
| 12 | 5 | 0.5-1.2 | 177 | 1294 |
| 16 | 10 | 0.5-0.8 | 180 | 1142 |
| 17 | 15 | 0.2-0.3 | 185 | 999 |
Embodiment 7
The influence of non-solvent water content in the preparation liquid
Mass ratio is respectively 10/5/0/85,10/5/3/82,10/5/5/80, the Kynoar of 10/5/6.5/78.5, polyvinylpyrrolidone, triethyl phosphate about 70 ℃ in flask separately abundant stirring and dissolving 48h, dissolve fully to PVDF, solution keeps clarification; Above-mentioned each preparation liquid is filtered with Buchner funnel, carry out vacuum defoamation a few hours, set aside for use then.The PET nonwoven is installed on compound knifing machine, and the cloth speed of walking of regulating linear speed controller control nonwoven is 1.5m/s; Mix up edge of a knife thickness 150 μ m between scraper and the supporting layer with feeler gauge; 26.5 ℃ of environment temperatures are that 25 ℃ preparation liquid is poured in the hopper with temperature, carry out knifing then, solution is coated with to be scraped on the supporting layer, and the time of moving in air is 5s, is immersed in subsequently in 25 ℃ the coagulating bath, coagulating bath is a deionized water, the very fast freezing film of PVDF solution.Room temperature during knifing is 26.5 ℃, and humidity is controlled at 80%.The composite membrane of scraping was soaked in deionized water about 7 days; Then film is carried out post processing, wet film is soaked 24h in 15% glycerine water solution, at last with film nature airing.
The mensuration of water flux and the sign of SEM are with embodiment 1.The thickness of prepared composite membrane, average pore size and water flux see Table 8.Prepared composite membrane configuration of surface is seen Fig. 7.
The non-solvent water content is to the Effect on Performance of PVDF composite membrane in table 8. preparation liquid
| The film numbering | The content of non-solvent water (wt%) | Film surface average pore size μ m | Thickness μ m | Water flux L/h.m 2(MPa) |
| 18 | 3 | 0.1-0.2 | 160 | 370 |
| 19 | 5 | 0.1-0.2 | 168 | 400 |
| 20 | 6.5 | 0.1-0.5 | 177 | 500 |
Embodiment 8
Preparation liquid Temperature Influence during knifing
Mass ratio be 10/5//85 Kynoar, polyvinylpyrrolidone, dimethyl sulfoxide (DMSO) about 70 ℃ in flask separately abundant stirring and dissolving 48h, dissolve fully to PVDF, solution keeps clarification; Above-mentioned preparation liquid is filtered with Buchner funnel, carry out vacuum defoamation a few hours, set aside for use then.The PET nonwoven is installed on compound knifing machine, and the cloth speed of walking of regulating linear speed controller control nonwoven is 1.5m/s; Mix up edge of a knife thickness 150 μ m between scraper and the supporting layer with feeler gauge; 27 ℃ of environment temperatures, the preparation liquid of set aside for use is divided into four parts, be heated to 35 ℃, 45 ℃, 55 ℃, 65 ℃ respectively, the preparation liquid of each temperature carries out knifing respectively, solution is coated with to be scraped on the supporting layer, and the time of moving in air is 5s, is immersed in subsequently in 28 ℃ the coagulating bath, coagulating bath is a deionized water, the very fast freezing film of PVDF solution.Room temperature during knifing is 27 ℃, and humidity is controlled at 80%.The composite membrane of scraping was soaked in deionized water about 7 days; Then film is carried out post processing, wet film is soaked 24h in 15% glycerine water solution, at last with film nature airing.
The mensuration of water flux and the sign of SEM are with embodiment 1.The thickness of prepared composite membrane, average pore size and water flux see Table 9.The configuration of surface of various films is seen accompanying drawing 7.
The non-solvent water content is to the Effect on Performance of PVDF composite membrane in table 9. preparation liquid
| The film numbering | The temperature of preparation liquid ℃ during knifing | Film surface average pore size μ m | Thickness μ m | Water flux L/h.m 2(MPa) |
| 21 | 35 | 0.2-0.4 | 168 | 1067 |
| 22 | 45 | 0.2-0.5 | 167 | 1143 |
| 23 | 55 | 0.3-0.6 | 165 | 1470 |
| 24 | 65 | 0.5-0.8 | 163 | 1607 |
Claims (7)
1. the preparation method of a polyvinylidene fluoride flat plate microporous compound film, the step of method is:
1) Kynoar, additive, non-solvent are dissolved in the organic solvent, heating stirs, and filters, and obtains the preparation liquid that Kynoar concentration is 8～14wt% after the vacuum defoamation, set aside for use, additive is: polyvinylpyrrolidone K30 or Macrogol 6000;
2) be that 25～65 ℃ preparation liquid is coated on the supporter of nonwoven or woven dacron by knifing machine with temperature range, regulate the edge of a knife of knifing machine and the thickness that the distance between the supporter is controlled knifing, scraping film thickness is 100～200 μ m, and the cloth speed of walking of supporting layer is 1.0m/min or 1.5m/min;
3) supporter that will be coated with preparation liquid moves a period of time in air, and the sky time of exposing to the sun is 5～25s;
4) supporter that is coated with preparation liquid after sky is exposed to the sun immerses in the coagulating bath, forms microporous compound film, and coagulation bath temperature is 0～25 ℃;
5) microporous compound film that forms was soaked in deionized water 6～9 days, then microporous compound film is dipped in the glycerine water solution of 15～20% (v/v) and carries out hydrophilicity-imparting treatment, the processing time is 20～24h;
6) microporous compound film is taken out natural airing from glycerine water solution.
2. the preparation method of a kind of polyvinylidene fluoride flat plate microporous compound film according to claim 1, it is characterized in that, said organic solvent is: N, N-dimethylacetylamide, N, dinethylformamide, N-methyl pyrrolidone, dimethyl sulfoxide (DMSO) or triethyl phosphate.
3. the preparation method of a kind of polyvinylidene fluoride flat plate microporous compound film according to claim 1 is characterized in that, said additive addition is 2～7wt%, the joining day be before Kynoar is dissolved in organic solvent, afterwards or with it simultaneously.
4. the preparation method of a kind of polyvinylidene fluoride flat plate microporous compound film according to claim 1,, it is characterized in that said polyvinylpyrrolidone K30, molecular weight are 30,000.
5. the preparation method of a kind of polyvinylidene fluoride flat plate microporous compound film according to claim 1 is characterized in that, said Macrogol 6000, molecular weight are 5500.
6. the preparation method of a kind of polyvinylidene fluoride flat plate microporous compound film according to claim 1 is characterized in that non-solvent is a deionized water in the preparation liquid, and content is 0～10wt%.
7. the preparation method of a kind of polyvinylidene fluoride flat plate microporous compound film according to claim 1 is characterized in that, said nonwoven, thickness are 100～115 μ m, and the aperture is 500～700 μ m.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410067170 CN1272093C (en) | 2004-10-12 | 2004-10-12 | Method for preparing polyvinylidene fluoride flat plate microporous compound film |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 200410067170 CN1272093C (en) | 2004-10-12 | 2004-10-12 | Method for preparing polyvinylidene fluoride flat plate microporous compound film |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1621140A CN1621140A (en) | 2005-06-01 |
| CN1272093C true CN1272093C (en) | 2006-08-30 |
Family
ID=34765015
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 200410067170 Expired - Fee Related CN1272093C (en) | 2004-10-12 | 2004-10-12 | Method for preparing polyvinylidene fluoride flat plate microporous compound film |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN1272093C (en) |
Families Citing this family (30)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100384521C (en) * | 2005-09-13 | 2008-04-30 | 浙江大学 | Method for improving hydrophilicity of polymer porous membrane by dentritic branching molecule |
| CN100337729C (en) * | 2005-10-22 | 2007-09-19 | 燕山大学 | Chemical modification technique for microfiltering separation film of polyvinylidene fluoride |
| CN100337730C (en) * | 2005-10-24 | 2007-09-19 | 浙江大学 | Process for preparing structure symmetric polyether sulfone hydrophilic porous film |
| CN1843600B (en) * | 2006-03-28 | 2010-11-24 | 上海一鸣过滤技术有限公司 | Intensified microporous membrane of polyethersulfone and method for preparing the same |
| CN101269302B (en) * | 2008-05-06 | 2011-08-31 | 南京奥特高科技有限公司 | Non-crystallization permanent hydrophilic PVDF membrane material and preparation method thereof |
| CN101422701B (en) * | 2008-11-25 | 2014-08-06 | 北京仁创科技集团有限公司 | Filter unit and manufacture method thereof and water treatment device |
| US9393530B2 (en) * | 2010-04-05 | 2016-07-19 | Mitsubishi Rayon Co., Ltd. | Process for production of porous membrane |
| CN101850217B (en) * | 2010-05-26 | 2012-05-30 | 浙江大学 | Method for preparing skin-free homogeneous structural polyvinylidene fluoride transfer film |
| CN101837247B (en) * | 2010-06-03 | 2012-11-21 | 武汉智迅创源科技发展股份有限公司 | Liquid medicine filtering membrane and preparation method thereof |
| CN102477164A (en) * | 2011-09-30 | 2012-05-30 | 深圳光启高等理工研究院 | Preparation method for inhomogeneous dielectric substrate |
| CN102477165B (en) * | 2011-09-30 | 2013-03-13 | 深圳光启高等理工研究院 | Preparation method for inhomogeneous dielectric substrate |
| CN102512971B (en) * | 2011-12-09 | 2013-10-16 | 苏州中色德源环保科技有限公司 | Method for preparing composite flat ultrafiltration membrane |
| CN102580548B (en) * | 2011-12-20 | 2017-02-22 | 湖南省天骑医学新技术股份有限公司 | Detection method applied to membrane separation and membrane transparent liquid |
| CN102580555B (en) * | 2012-03-05 | 2014-06-04 | 常州汇恒膜科技有限公司 | Continuous production process and equipment for micro-filtration and ultra-filtration membranes |
| CN102626593B (en) * | 2012-04-13 | 2015-05-06 | 清华大学 | Formula of acid and alkali-resistant and anti-pollution ultrafiltration membrane and preparation method thereof |
| CN102895885A (en) * | 2012-10-25 | 2013-01-30 | 金洪义 | Single-skin layer composite filter membrane and preparation method thereof |
| CN103420793B (en) * | 2013-07-31 | 2015-11-18 | 大连理工大学 | The method of a kind of polyvinylidene difluoride (PVDF)-polydimethylsiloxane composite membrane separation and purification butanols |
| CN104324621A (en) * | 2014-03-12 | 2015-02-04 | 唐山曹妃甸海清源科技有限公司 | High throughput polyvinylidene fluoride flat-sheet film with controllable pore structure, and preparation method thereof |
| CN104984663A (en) * | 2015-06-15 | 2015-10-21 | 黄义忠 | Film casting liquid for PVDF flat membrane and preparing method for PVDF flat membrane |
| CN105536571A (en) * | 2015-12-25 | 2016-05-04 | 成都美富特膜科技有限公司 | Membrane casting solution for manufacturing disc type membrane |
| CN106823855B (en) * | 2017-03-03 | 2019-02-01 | 河北工业大学 | A kind of preparation method of very hydrophobic microporous barrier |
| CN106582325B (en) * | 2017-03-03 | 2019-01-29 | 河北工业大学 | A kind of preparation method of very hydrophobic polyvinylidene fluoride microporous film |
| CN106823832B (en) * | 2017-03-24 | 2019-08-20 | 河海大学 | Intelligent integrated formula automatic scraping film device |
| CN109603567B (en) * | 2018-12-24 | 2021-03-16 | 郑州轻工业学院 | Preparation method and application of PVDF-PVP highly porous membrane |
| CN110003591B (en) * | 2019-03-29 | 2021-02-26 | 华中科技大学 | Preparation method of flexible fiber and flexible fiber |
| CN110346389A (en) * | 2019-06-20 | 2019-10-18 | 中国人民解放军南部战区总医院 | One kind being film-made instrument for transmission electron microscope sample |
| CN111318173A (en) * | 2020-03-31 | 2020-06-23 | 华北理工大学 | Preparation device of separation membrane with controllable microporous structure and control method of bathing angle of membrane body |
| CN111905571A (en) * | 2020-07-14 | 2020-11-10 | 江苏千里膜业科技有限公司 | Preparation method of MBR (membrane bioreactor) flat dry film for industrial sewage treatment |
| CN111992059A (en) * | 2020-09-01 | 2020-11-27 | 安徽美邦树脂科技有限公司 | PVB-based ultrafiltration membrane and preparation method thereof |
| CN112619449B (en) * | 2020-12-16 | 2023-05-02 | 杭州科百特科技有限公司 | Nylon membrane and preparation method and application thereof |
-
2004
- 2004-10-12 CN CN 200410067170 patent/CN1272093C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| CN1621140A (en) | 2005-06-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN1272093C (en) | Method for preparing polyvinylidene fluoride flat plate microporous compound film | |
| CN1730141A (en) | Process for preparing co-mixed polyethersulfone platform complex film | |
| CN101269302B (en) | Non-crystallization permanent hydrophilic PVDF membrane material and preparation method thereof | |
| CN104607063B (en) | PVDF permanently hydrophilic ultrafiltration membrane and modification method thereof | |
| CN105120992B (en) | Polyvinylidene fluoride hollow fiber membrane and its preparation | |
| EP2531282B1 (en) | Method for producing porous silicon molded bodies | |
| Malik et al. | Design and synthesis of polymeric membranes using water-soluble pore formers: An overview | |
| CN107970782B (en) | Polymer film with high interconnected pore structure and preparation method thereof | |
| CN101874988A (en) | Separating film and preparation method thereof | |
| CN102886213B (en) | Separate film, its manufacture method and include its water treatment facilities | |
| CN101224392A (en) | Fabricating method of fiber powder modified polymer microporous film | |
| CN106582312A (en) | Hydrophilic polyvinylidene fluoride two-layer membrane and preparation method thereof | |
| CN1704152A (en) | Preparation of hydrophilic polyvinylidene fluoride microporous membrane | |
| CN108211809A (en) | The polyvinylidene fluoride film and its manufacturing method of a kind of permanent hydrophilic | |
| CN110975649A (en) | Modified polyvinylidene fluoride ultrafiltration membrane and preparation method thereof | |
| CN105749765A (en) | Preparation method of high-performance cellulose triacetate forward osmosis membrane | |
| CN1306883A (en) | Hollow fiber membrane and producing method | |
| KR101230842B1 (en) | Manufacturing method of porous asymmetric membrane with various pore size and its product manufactured thereby | |
| JPH0278425A (en) | Hydrophilic and dryable semipermeable membrane based on polyvinylidene fluoride | |
| CN105169971A (en) | Reverse osmosis composite membrane | |
| CN114904404A (en) | Mixed matrix forward osmosis membrane based on MOF-808(Zr) and preparation method thereof | |
| CN1480248A (en) | Separation membrane made from cellulose and its preparing method | |
| JP2020533166A (en) | Microporous membrane and its manufacturing method | |
| CN109173745B (en) | Hollow fiber ultrafiltration membrane and preparation method thereof | |
| WO2020231919A1 (en) | Additive manufacturing of self-assembled polymer films |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C17 | Cessation of patent right | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20060830 Termination date: 20091112 |