JP6211059B2 - Ultrafiltration membranes made from sulfonated polyphenylene sulfone - Google Patents

Description

  The present invention relates to an ultrafiltration membrane comprising a membrane substrate layer (S) based on a sulfonated polyarylene ether sulfone polymer, in particular to a sulfonated polyphenylene sulfone (sPPSU) polymer and a process for its production. Furthermore, the present invention relates to an ultrafiltration process using the membrane.

BACKGROUND OF THE INVENTION Ultrafiltration (UF) is a membrane process between microfiltration (MF) and nanofiltration (NF). The pore size of such membranes is usually in the range of about 2-100 nm [1]. The polymer process retains the polymer and colloid when applying a driving force of 1 to 3 bar. These larger molecules are retained by the membrane, while the smaller molecules are free to permeate with the solvent. Thus, the UF mechanism relies primarily on size exclusion. This process is widely applied in industries such as juices and beverages [2,3], dialysis [4], and water purification.

  An ideal UF membrane should have the following properties: (1) hydrophilicity and high water flux; (2) high porosity with sponge-like (no macrovoid) and interconnected pore structure; (3) Sufficient mechanical strength with good long-term film stability.

  Most UF membranes form asymmetric membranes from materials such as polysulfone (PSU) [5], polyfluorinated (vinylidene) (PVDF) [6], cellulose acetate (CA) [7] and polyimide (PI) [8]. To be produced by a phase inversion process. Among these, polyaryl sulfones are known for their chemical and mechanical resistance, thermal stability, and ability to withstand a wide range of temperature and corrosive environments [9]. However, for the hydrophobicity of some of the above polymers, namely PSU and PVDF, UF membranes made from these polymers are also affected by poor wettability due to aqueous media, macrovoid formation and fouling tendency . As a result, additives that act as a hydrophilizing agent and pore-forming agent for such polymer materials for UF applications generally, such as polyethylene glycol (PEG) [10, 11], polyvinylpyrrolidone (PVP) Need to be included.

  There is a need for advanced UF separation techniques that utilize membranes with excellent chemical resistance and thermal stability.

  In previous studies, sulfonated PPSU [12] having a functionality of 0.8-2.5 meq / g and polymer blends of CA and sulfonated PPSU [13] have been applied to electrodialysis. However, UF membranes made of directly sulfonated materials made without blending with other polymeric materials of low functionality are highly desirable.

SUMMARY OF THE INVENTION The above problem is particularly true with a completely porous and sponge-like morphology through a phase inversion process using sulfonated polyphenylenesulfone (sPPSU) synthesized via a direct sulfonation route. This is solved by providing an asymmetric ultrafiltration membrane (UF). With sulfonated monomer content, newly developed membranes show high water permeability. The hydrophilicity of a negatively charged UF membrane can reduce the tendency to fouling. The method described in the present invention can be extended to produce fully exposed asymmetric hollow fiber membranes from the polymer materials described above for various applications in the membrane industry. In particular, these newly developed UF membranes are used for hemodialysis, protein separation / fractionation, virus removal, recovery of vaccines and antibiotics from fermentation broth, wastewater treatment, milk / dairy product concentration, fruit juice clarification Etc. have the potential to be applied to such processes. The negative charge in these UF asymmetric membranes can also enhance the separation performance of specific protein pairs / mixtures. Such membranes can also be applied as membrane substrates with several modifications for other membrane applications such as nanofiltration and forward osmosis membranes. With regard to membrane construction, the method described in the present invention can be extended to produce fully exposed UF asymmetric hollow fiber membranes.

  More specifically, to investigate the effect of hydrophilicity on UF performance, two new materials, 2.5 mol% and 5.0 mol% (5,5'-disulfone-4,4'- Polyphenylenesulfone (sPPSU) directly sulfonated with dichlorodiphenylsulfone) sDCDPS monomer was utilized. Non-sulfonated PPSU was used as a benchmark to compare performance.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows the morphology of the as-cast film: (a) PPSU; (b) sPPSU-2, 5%; (c) sPPSU-5%
FIG. 2 shows probability density curves for UF membranes with different sulfonated contents: (a) PPSU; (b) sPPSU-2.5%; (c) sPPSU-5%

Detailed description of the invention:
A. General definition:
A “water treatment membrane” is generally a translucent membrane that allows for the separation of dissolved and suspended water particles, the separation process itself being either pressure driven or electrically driven. It may be either.

  Examples of membrane applications include pressure-driven membrane technologies such as microfiltration (MF; very small, suspended particles, colloids, pore size for separation of bacteria of about 0.08-2 μm), ultrafiltration (UF; pore size for separation of organic particles, viruses, bacteria, colloids above 1000 MW is about 0.005-0.2 μm), nanofiltration (NF, organic particles above 300 MW, trihalomethane (THM) precursor Pore size for separation of viruses, bacteria, colloids, dissolved solids from 0.001 to 0.01 μm) or reverse osmosis (RO, ions, separation of organic substances above 100 MW is 0.0001 to 0.001 μm).

  The molecular weight of the polymer is measured by GPC, especially in DMAc (dimethylacetamide), unless specified as Mw values. In particular, GPC measurements were performed using dimethylacetamide (DMAc) containing 0.5% by weight lithium bromide. A polyester copolymer was used as the column material. Column calibration was performed using a narrow distribution of PMMA standards. When a flow rate of 1 ml / min was selected, the concentration of the injected polymer solution was 4 mg / ml.

"Sulfonated" molecule (also referred to as or sulfo) at least one sulfonate -SO ₃ H type residue, or _-SO ³ - ^{M +} -type forms the corresponding metal salt, for example, M = Na, K Or it has the form of the alkali metal salt of Li.

  In the context of the present invention, “partially sulfonated” simply means a polymer in which a certain percentage of the monomer components are sulfonated and contain at least one sulfo group residue. In particular, about 0.5 to 4.5 mol% or about 1 to 3.5 mol% of the monomer component or repeating unit of the polymer has at least one sulfo group. The sulfonated monomer unit can have one or more, for example two, three, four, especially two sulfo groups. When the sulfo content is less than 0.5 mol%, hydrophilicity is not improved, and when the sulfo content exceeds 5 mol%, a film having macrovoids and low mechanical stability is obtained.

（式中、Ｒは上に規定される連結基、例えば、−Ｏ−、アルキレン、又はフッ化又は塩素化アルキレンを表すか又は上で定義された更に置換され得る化学結合を表す）
が挙げられる。 “Arylene” means a divalent, mononuclear or polynuclear aromatic ring group, in particular optionally mono- or polysubstituted, for example the same or different, in particular the same lower alkyl, for example C ₁ -C ₈ or by C ₁ -C ₄ alkyl group, mono-, di- or trisubstituted, mononuclear, an aromatic ring group dinuclear or trinuclear, and 6-20, for example, 6-12 ring carbons Has atoms. Two or more ring groups can be fused, or more preferably a non-fused ring, or two adjacent rings are a C—C single bond or ether (—O—) or alkylene bridge, or a halogenated alkylene bridge or sulfono. It can be linked via a group R selected from the group (—SO ₂ —). The arylene group may be selected, for example, from mononuclear, dinuclear and trinuclear aromatic ring groups, where in the case of dinuclear and trinuclear groups, the aromatic ring is optionally fused; If the aromatic rings are not fused, they are linked two by one through a C—C single bond, —O—, or an alkylene or halogenated alkylene bridge. By way of example, the phenylenes described below, for example hydroquinone; bisphenylene; naphthylene; phenanthrylene:

Wherein R represents a linking group as defined above, eg, —O—, alkylene, or fluorinated or chlorinated alkylene, or a chemical bond that may be further substituted as defined above.
Is mentioned.

“Alkylene” is a straight or branched divalent hydrocarbon group having 1 to 10 or 1 to 4 carbon atoms, such as a C _{1 to} C ₄ alkylene group, such as —CH _{2. -, - (CH 2) 2} -, (CH 2) 3 -, - (CH 2) 4 -, - (CH 2) 2 -CH (CH 3) -, - CH 2 -CH (CH 3) -CH _2- , (CH ₂ ) ₄ — is represented.

“Lower alkyl” refers to a linear or branched “alkyl” residue having from 1 to 8 carbon atoms. Examples are methyl, ethyl, n- propyl, isopropyl, n- butyl, 2-butyl, isobutyl or _C 1 -C ₄ are selected from tert- butyl - alkyl group, or a _C 1 -C defined above C ₁ -C ₆ -alkyl groups selected from _4- alkyl groups, as well as pentyl, 1-methylbutyl, 2-methylbutyl, 3-methylbutyl, 2,2-dimethylpropyl, 1-ethylpropyl, hexyl, 1,1 -Dimethylpropyl, 1,2-dimethylpropyl, 1-methylpentyl, 2-methylpentyl, 3-methylpentyl, 4-methylpentyl, 1,1-dimethylbutyl, 1,2-dimethylbutyl, 1,3-dimethyl Butyl, 2,2-dimethylbutyl, 2,3-dimethylbutyl, 3,3-dimethylbutyl, 1-ethylbutyl, 2-ethylbutyl Le, 1,1,2-trimethyl propyl, 1,2,2-trimethyl propyl, 1-ethyl-1-methylpropyl, 1-ethyl-2-methylpropyl.

  An “asymmetric membrane” (or anisotropic membrane) has a thin porous or non-porous selective barrier supported by a much thicker porous substrate (H. Susanto, M. Ulbricht, Membrane See also Operations, Innovative Separations and Transformations, ed. E. Driolo, L. Giorno, Wiley-VCH-Verlag GmbH, Weinheim, 2009, page 21).

B. Special Embodiments The present invention provides the following special embodiments:
1. Sponge-like asymmetric membrane, in particular an asymmetric membrane applicable as a UF membrane, comprising a substrate layer (S) of at least one asymmetric membrane comprising at least one partially sulfonated polyphenylenesulfone polymer (P1).

（式中、
Ａｒは二価の芳香族残基を表し、
Ｍ１及びＭ２から選択される少なくとも１つのモノマー単位はスルホン化され且つ
ここでＭ１及び／又はＭ２の芳香環が更に１つ以上の同じ又は異なる置換基（−ＳＯ_３Ｈ型のスルホ残基、又はその対応する−ＳＯ_３ ⁻Ｍ^＋型の金属塩の形態とは異なる）、特に前記基材層の特性プロフィール（例えば、機械的強度、又は透過性）を改善するのに適した置換基を有してよい）
のモノマー単位から構成されている、前記膜。適した置換基は、低級アルキル置換基、例えば、メチル又はエチルであり得る。 2. Embodiment 2. The membrane of embodiment 1, wherein the partially sulfonated polyethersulfone polymer (P1) is a polyarylene ethersulfone polymer and has the general formula

(Where
Ar represents a divalent aromatic residue,
At least one monomer unit selected from M1 and M2 is sulfonated and wherein the aromatic ring of M1 and / or M2 further has one or more same or different substituents (sulfo residues of the —SO ₃ H type, or the corresponding -SO ₃ ^- different from the form of M ⁺ -type metal salts), in particular property profile of the base layer (e.g., have a substituent suitable for improving the mechanical strength, or transparency) You may)
The film is composed of monomer units. Suitable substituents can be lower alkyl substituents such as methyl or ethyl.

  3. One of the preceding embodiments, wherein the membrane is about 0.5-5 mol% or 1-3.5 mol in the partially sulfonated polyarylene sulfone polymer (especially polyphenylene sulfone polymer) (P1). % Of the polymer monomer component or repeating unit having at least one sulfo group.

（式中、Ａｒは上で定義された通りであり、且つ
ＨａｌはＦ、Ｃｌ、Ｂｒ又はＩである）
の非スルホン化モノマーであって、
Ｍ１ａ及び／又はＭ２ａの芳香環が更にＭ１及びＭ２について上記された１つ以上の置換基を有し得る、前記非スルホン化モノマー、
例えば、Ｍ１ａモノマー：

及び
例えば、Ｍ２ａモノマー：

と、一般式Ｍ１ｂ及びＭ２ｂ

（式中、Ａｒ及びＨａｌは上で定義された通りであり、且つｎ及びｍは独立して０、１又は２であるが、但し、ｎ及びｍは同時に０ではないことを条件とする）
の少なくとも１つのスルホン化モノマーであって、
Ｍ１ｂ及び／又はＭ２ｂの芳香環が更にＭ１及びＭ２について上記された１つ以上の置換基を有してよく、特に、スルホン化モノマーＭ１ｂ及び／又はＭ２ｂのモル比が、Ｍ１ａ、Ｍ１ｂ、Ｍ２ａ及びＭ２ｂの全モル数を基準として０．５〜５モル％の範囲であり、且つ（Ｍ１ａ＋Ｍ１ｂ）：（Ｍ２ａ＋Ｍ２ｂ）のモル比が約０．９５〜１．０５、特に０．９７〜１．０３である、前記スルホン化モノマー、
例えば、Ｍ１ｂモノマー：

及び
例えば、Ｍ２ｂモノマー：

と、を重合することによって得られる、前記膜。 4). The membrane of one of the preceding embodiments, wherein the partially sulfonated polyarylene sulfone polymer (especially polyphenylene sulfone polymer) (P1) has the general formulas M1a and M2a

Wherein Ar is as defined above and Hal is F, Cl, Br or I.
A non-sulfonated monomer of
The non-sulfonated monomer, wherein the aromatic ring of M1a and / or M2a may further have one or more substituents as described above for M1 and M2;
For example, M1a monomer:

And, for example, the M2a monomer:

And general formulas M1b and M2b

Wherein Ar and Hal are as defined above, and n and m are independently 0, 1 or 2, provided that n and m are not 0 at the same time.
At least one sulfonated monomer of
The aromatic ring of M1b and / or M2b may further have one or more substituents as described above for M1 and M2, in particular the molar ratio of the sulfonated monomers M1b and / or M2b is M1a, M1b, M2a and In the range of 0.5-5 mol% based on the total number of moles of M2b, and the molar ratio of (M1a + M1b) :( M2a + M2b) is about 0.95 to 1.05, especially 0.97 to 1.03 The sulfonated monomer,
For example, M1b monomer:

And, for example, M2b monomer:

And the film obtained by polymerizing.

  5. The membrane of one of the preceding embodiments, wherein the partially sulfonated polyarylene sulfone polymer (especially polyphenylene sulfone polymer) (P1) is a block copolymer or a random copolymer.

の非スルホン化繰り返し単位と、式（２）

のスルホン化繰り返し単位を含む、前記膜。 6). The membrane of one of the preceding embodiments, wherein the partially sulfonated polyarylene sulfone polymer (especially polyphenylene sulfone polymer) (P1) is of the formula (1)

A non-sulfonated repeating unit of formula (2)

The membrane comprising sulfonated repeating units of:

の非スルホン化繰り返し単位と、式（２ａ）

のスルホン化繰り返し単位を含む、前記膜。 7). Embodiment 3. The membrane of embodiment 3, wherein the partially sulfonated polyarylene sulfone polymer (especially polyphenylene sulfone polymer) (P1) is of the formula (1a)

A non-sulfonated repeating unit of formula (2a)

The membrane comprising sulfonated repeating units of:

  8). The membrane of embodiment 6 or 7, wherein the sulfonated repeating unit 2a is 0.1 to 0.1 based on the total number of moles of the repeating units (1) and (2) or (1a) and (2a). Said film, contained in a molar ratio of ˜20 mol%, 0.2 to 10 mol%, in particular 0.5 to 5 mol% or 1 to 3.5 mol%.

  9. One of the preceding embodiments, wherein the polymer P1 is in the range of 50,000 to 150,000, especially 70,000 to 100,000 g / mol as measured by GPC in DMAc. The membrane having Mw. If Mw is greater than 150,000, the polymer solution viscosity is too high. When Mw is below 50,000, the resulting film exhibits limited mechanical strength.

  10. The membrane of any one of the preceding embodiments, wherein at least one substrate layer (S) exhibits a sponge-like and macrovoid-free structure completely, ie substantially over the entire cross section. film.

  11. The membrane of any one of the preceding embodiments, wherein the substrate layer (S) has a layer thickness in the range of 30-400 μm, 50-250 μm or 80-150 μm. If the layer thickness exceeds 400 μm, the permeability of the membrane is low, and if the layer thickness is less than 30 μm, defects can reduce the selectivity.

  12 The membrane of any one of the previous embodiments, wherein the sulfonated polymer (P1) is produced from a monomer mixture comprising an already sulfonated monomer of type M1b.

  13. A process for producing a membrane according to any one of the preceding claims, comprising at least one partially sulfonated polyarylene sulfone polymer (especially polyphenylene) as defined in any one of embodiments 1-7. Said process comprising the production of at least one substrate layer (S) by applying a polymer solution comprising a sulfone polymer) (P1).

  14 Embodiment 14. The method according to embodiment 13, wherein the polymer content of the solution is in the range of 10-40 wt%, 12-30 wt%, or 16-24 wt%. When the polymer content is above the range, the solution viscosity of the dope solution is too high for the spinning process, but below the range, it is too slow for spinning and film formation occurs.

  15. The polymer solution is N-methylpyrrolidone (NMP), N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), tri-ethyl phosphate, tetrahydrofuran (THF), 1,4-dioxane, methyl ethyl ketone ( MEK), or at least one solvent selected from combinations thereof; additionally selected from ethylene glycol, diethylene glycol, polyethylene glycol, glycerol, methanol, ethanol, isopropanol, polyvinylpyrrolidone, or combinations thereof It may contain at least one further additive, wherein the additive is 0-50% by weight, 1-40% by weight or 1-25% by weight or 5-15% by weight based on the total weight of the polymer solution. The method according to the the, embodiment 14 contained in the polymer solution in% of the range.

  16. The method according to embodiment 13 or 14, wherein the at least one substrate layer (S) is produced by applying a phase inversion method using water as a coagulation bath.

  17. Embodiment 16 wherein water is optionally mixed with at least one lower alcohol, in particular methanol, ethanol, isopropanol and optionally mixed with at least one solvent as defined in embodiment 21 and applied as a coagulant. The method described in 1.

  18. Ultrafiltration membrane comprising at least one membrane according to any one of claims 1 to 11 or manufactured according to any one of embodiments 13 to 17.

  19. The ultrafiltration membrane according to embodiment 18, in the form of a flat sheet, hollow fiber or capillary.

  20. An ultrafiltration method using the membrane according to embodiment 18 or 19.

  21. 21. The method of embodiment 20, applied to hemodialysis, protein separation / fractionation, virus removal, recovery of vaccines and antibiotics from fermentation broth, wastewater treatment, milk / dairy product concentration, fruit juice clarification and the like.

  22. A base for producing a membrane as described in any one of embodiments 1-12 or produced according to any one of embodiments 13-7 for use in other applications such as FO or NF. Use as a material.

C. Further Embodiments of the Invention The manufacture of membranes such as UF membranes and their use in differently structured filtration modules is known in the art. See, for example, [19] MC Porter et al., Handbook of Industrial Membrane Technology (William Andrew Publishing / Noyes, 1990).

1. Manufacture of hydrophilic membrane substrate layer (S) 1.1 Manufacture of polymer P1 Unless otherwise stated, the manufacture of polymers is generally carried out applying standard methods of polymer technology. In general, the reagents and monomer components used herein are either commercially available or are well known in the art or readily available to one of ordinary skill in the art through prior art disclosures. is there.

  According to a first particular embodiment, the partially sulfonated polyarylene sulfone polymer (especially the polyphenylene sulfone polymer) P1 comprises a monomer of the M1a and M2a type and at least one sulfonated variant of the M1b and M2b type Prepared by reacting a mixture of monomers including

  In general, sulfonated polyarylene sulfone polymers (especially polyphenylene sulfone polymers) P1 are taught, for example, by [20] RN Johnson et al., J. Polym. Sci. A-1, Volume 5, 2375 (1967). As shown, for example, it can be synthesized by reacting a dialkali metal salt of an aromatic diol with an aromatic dihalide.

  Examples of suitable aromatic dihalides (M1a) include bis (4-chlorophenyl) sulfone, bis (4-fluorophenyl) sulfone, bis (4-bromophenyl) sulfone, bis (4-iodophenyl) sulfone, bis ( 2-chlorophenyl) sulfone, bis (2-fluorophenyl) sulfone, bis (2-methyl-4-chlorophenyl) sulfone, bis (2-methyl-4-fluorophenyl) sulfone, bis (3,5-dimethyl-4- Chlorophenyl) sulfone, bis (3,5-dimethyl-4-fluorophenyl) sulfone, and their corresponding lower alkyl substituted analogs. They may be used individually or as a combination of two or more of their monomer components. Specific examples of dihalides are bis (4-chlorophenyl) sulfone ((4,4'-dichlorophenyl) sulfone; also referred to as DCDPS) and bis (4-fluorophenyl) sulfone.

  Examples of suitable divalent aromatic alcohols (M2a) to be reacted with aromatic dihalides are hydroquinone, resorcinol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,7 -Dihydroxynaphthalene, 4,4'-bisphenol, 2,2'-bisphenol, bis (4-hydroxyphenyl) ether, bis (2-hydroxyphenyl) ether, 2,2-bis (4-hydroxyphenyl) propane, 2, , 2-bis (3-methyl-4-hydroxy-phenyl) propane, 2,2-bis (3,5-dimethyl-4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, and 2,2- Bis (3,5-dimethyl-4-hydroxyphenyl) hexafluoropropane That. Of these, hydroquinone, resorcinol, 1,5-dihydroxynaphthalene, 1,6-dihydroxynaphthalene, 1,7-dihydroxynaphthalene, 2,7-dihydroxynaphthalene, 4,4′-biphenol, bis (4- Hydroxyphenyl) ether, and bis (2-hydroxyphenyl) ether. They can be used individually or as a combination of two or more monomer components M2a. Particular examples of such divalent aromatic alcohols are 4,4'-bisphenol and 2,2'-bisphenol.

  Compounds M1b and M2b are mono- or polysulfonated equivalents of the non-sulfonated monomer components M1 and M1b described above. Such sulfonated monomer components are well known in the art or can be readily utilized in routine organic synthesis methods. For example, sulfonated aromatic dihalides, such as sodium 5,5′-sulfonylbis (2-chlorobenzenesulfonate) (a 5,5′-bissulfonated analog of DCDPS), for example, [21] M. Ueda et al. , J. Polym. Sci., Part A: Polym. Chem. Vol. 31, 853 (1993).

  The dialkali metal salt of the divalent aromatic phenol is obtained by a reaction between a divalent aromatic alcohol and an alkali metal compound such as potassium carbonate, potassium hydroxide, sodium carbonate or sodium hydroxide.

  Reactions between the divalent aromatic alcohol dialkali metal salts defined above and aromatic dihalides and sulfonated monomers are known in the art (eg, [22] Harrison et al., Polymer preprints (2000) 41 (2) (See 1239). For example, polar solvents such as dimethyl sulfoxide, sulfolane, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, N, N-dimethylformamide, N, N-dimethylacetamide, and diphenyl sulfone, Or a mixture thereof or a mixture of a non-polar organic solvent such as toluene and such a polar solvent may be applied.

  The reaction temperature is usually in the range from 140 to 320 ° C, in particular from 160 to 250 ° C. The reaction time may range from 0.5 to 100 hours, in particular from 2 to 15 hours.

  As a result of the excessive use of any one of divalent aromatic alcohol alkali metal salts and aromatic dihalides, end groups are formed which can be utilized for molecular weight control. Otherwise, if the two components are used in equimolar amounts, a monohydric phenol such as phenol, cresol, 4-phenylphenol or 3-phenylphenol, and an aromatic halide such as 4-chlorophenylsulfone 1-chloro-4-nitrobenzene, 1-chloro-2-nitrobenzene, 1-chloro-3-nitrobenzene, 4-fluorobenzophenone, 1-fluoro-4-nitrobenzene, 1-fluoro-2-nitrobenzene or 1-fluoro- Any one of 3-nitrobenzene is added for chain termination.

  Degree of polymerization of the polymer thus obtained (based on repeating units composed of one monomer (M1) and one monomer (M2), for example, repeating units (1) and (2) or (1a) and (2a) May be in the range of 40 to 120, in particular 50 to 80 or 55 to 75.

  Reactions of monomer components, in particular the reactions of aromatic dihalides M1a and M1b and divalent aromatic alcohol alkali metal salts of M2a and optionally M2b [14] Geise, GM et al., J. Poly. Sci, Part B: Polym Phys .: 48, (2010), 1685 and may be performed as described in the references cross-referenced therein.

1.2 Manufacture of substrate layer (S) The manufacture of a sponge-like, macrovoid-free substrate layer (S) is described, for example, in [15] CA Smolders et al., J. Membr. Sci .: Volume 73, ( 1992), 259, by applying well-known film forming techniques.

  A particular production method is known as a phase change method.

  In the first step, the partially sulfonated polymer (P1) produced above is dried under vacuum, for example in the range of 20-80 ° C., for example 60 ° C., to remove excess liquid.

  In the second step, a homogeneous dope solution containing the polymer in a suitable solvent system is prepared. The solvent system is N-methylpyrrolidone (NMP), N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), dimethylformamide (DMF), triethyl phosphate, tetrahydrofuran (THF), 1,4-dioxane, methyl ethyl ketone (MEK). ), Or a combination thereof; and at least one solvent selected from ethylene glycol, diethylene glycol, polyethylene glycol, glycerol, methanol, ethanol, isopropanol, polyvinylpyrrolidone, or combinations thereof The seed may contain further additives, wherein the additives are contained in the polymer solution in the range of 0 to 50% by weight or 0 to 30% by weight based on the total weight of the polymer solution. That.

  The polymer content ranges from 10 to 40% by weight, or from 16 to 24% by weight, based on the total weight of the solution. For example, a typical composition comprises sPPSU 2.5% / ethylene glycol / N-methylpyrrolidone (NMP> 99.5%) in a mass ratio of 20:16:64.

  In the third step, the polymer solution is then cast onto a solid support, for example a glass plate, using a casting knife that suitably applies a sufficiently thick polymer layer.

  Immediately thereafter, in the fourth step, the polymer layer provided on the support is immersed at room temperature in a coagulation bath containing an aqueous coagulation liquid, for example, a coagulation bath of tap water. Optionally, the water can be applied in admixture with at least one lower alcohol as coagulation bath, in particular methanol, ethanol, isopropanol and optionally in admixture with at least one solvent as defined above. The as-cast film was immersed in water for at least 2 days with constant water change to ensure complete removal of the solvent to induce phase change.

  As a result of this procedure, a membrane substrate showing a sponge-like structure without macrovoids is obtained.

FIG. 1 shows an SEM image of a UF membrane cast with non-sulfonated and sulfonated materials. FIG. 2 shows probability density curves for UF membranes with different sulfonated contents.

Experimental part Example 1: Production of membrane base polymer a) sPPSU 2.5%
In a 4I HWS vessel equipped with a stirrer, Dean-Stark trap, nitrogen inlet and temperature controller, 1.99 moles of dichlorodiphenylsulfone (DCDPS), 2.00 moles of 4,4′-dihydroxybiphenyl (DHBP) ), 0.05 mol of 3,3′-sodium di-disulfate-4,4′-dichlorodiphenylsulfone and 2.12 mol of potassium carbonate (particle size 36.2 μm) in nitrogen atmosphere in 2000 ml of NMP. Suspend under. The mixture is heated to 190 ° C. with stirring. Nitrogen is purged through the mixture at 30 l / hour and the mixture is maintained at 190 ° C. for 6 hours. Then 1000 ml NMP is added and the mixture is cooled. Allow the mixture to cool below 60 ° C. under nitrogen. After filtration, the mixture is precipitated in water containing 100 ml of 2m HCl. The precipitated product is extracted with hot water (at 85 ° C. for 20 hours) and dried under reduced pressure at 120 ° C. for 24 hours.

  Viscosity number: 88.7 ml / g (1 mass / volume% N-methylpyrrolidone solution at 25 ° C.).

  The content of sDCDPS monomer was estimated by taking the sulfur content of the polymer to be 2.4 mol%.

b) sPPSU 5%
In a 4I HWS vessel equipped with a stirrer, Dean-Stark-trap, nitrogen inlet and temperature controller, 1.90 moles dichlorodiphenyl sulfone (DCDPS), 2.00 moles 4,4′-dihydroxybiphenyl (DHBP) ), 0.1 mol of 3,3′-sodium di-disulfate-4,4′-dichlorodiphenylsulfone (sDCDPS) and 2.12 mol of potassium carbonate (particle size 36.2 μm) in 2000 ml of NMP. Suspend under nitrogen. The mixture is heated to 190 ° C. with stirring. Purge 30 liters / hour of nitrogen into the mixture and maintain the mixture at 190 ° C. for 6 hours. Then 1000 ml NMP is added and the mixture is cooled. Allow the mixture to cool below 60 ° C. under nitrogen. After filtration, the mixture is precipitated in water containing 100 ml of 2m HCl. The precipitated product is extracted with hot water (at 85 ° C. for 20 hours) and dried under reduced pressure at 120 ° C. for 24 hours.

  Viscosity number: 83.2 ml / g (1 mass / volume% N-methylpyrrolidone solution at 25 ° C.).

  The content of sDCDPS monomer was estimated to be 4.7 mol% when the sulfur content of the polymer was estimated.

Example 2: Production of a fully sponge-like and hydrophilic UF membrane from sPPSU 2.5% and sPPSU 5% Example 2 1 was synthesized as described above in [14].

  Merck N-methyl-2-pyrrolidone (NMP) and Sigma Aldrich ethylene glycol (EG) were used as solvents and additives, respectively, in the production of UF membranes. The composition of each dope solution was polymer / EG / NMP (mass%) = 13/16/71.

  The casting solution was degassed overnight before casting on a glass plate with a 100 μm thick casting knife. The as-cast film was then immediately immersed in a water coagulation bath at room temperature and maintained for 1 day to ensure complete precipitation.

  It can be observed that during the precipitation process, UF membranes cast from sPPSU materials with 2.5 mol% and 5 mol% DCDPS exhibit a slower settling rate compared to non-sulfonated PPSU materials. This is a common phenomenon because sulfonated materials tend to promote delayed demixing compared to non-sulfonated ones. However, compared to known sulfonated materials synthesized by a postsulfonation method that must be blended with other polymers to form an asymmetric membrane [16], the direct sulfonated polymers of the present invention are Independent asymmetric membranes can be formed without blending with other polymers.

  FIG. 1 shows an SEM image of a UF membrane cast with non-sulfonated and sulfonated materials. As expected, the unsulfonated PPSU membrane (FIG. 1a) exhibits numerous macrovoids due to instantaneous demixing, while the sulfonated PPSU membrane of the present invention (FIGS. 1b and 1c). Shows an interconnected pore structure that is completely spongy and has no macrovoids.

It can also be observed that the bottom of the membrane made of sulfonated material is completely porous. The typical membrane configuration shown in FIGS. 1b and 1c is highly preferred for UF applications and can potentially be applied as a membrane substrate for other types of membrane processes such as NF or forward osmosis (FO). Furthermore, they also show high hydrophilicity and high porosity compared to non-sulfonated ones. Table 1 shows the top and bottom contact angles and porosity of UF membranes made from both unsulfonated and sulfonated PPSU.

（式中、Ｑは透水体積流量（Ｌ／時間）であり、Αは有効ろ過面積（ｍ^２）であり、且つΔＰは膜貫通圧力（バール）である）。 Example 3 UF Performance Test of sPPSU-2, 5% Membrane, sPPSU-5% Membrane and PPSU Membrane The prepared flat membrane substrate was first tested and its pure water permeability (PWP) (L / m ² bar time) was measured using ultrafiltration membrane permeabilized cells with a sample diameter of 5 cm [17, 18].

(Where Q is the permeable volume flow rate (L / hour), Α is the effective filtration area (m ² ), and ΔP is the transmembrane pressure (bar)).

The membranes were then subjected to neutral solute (polyethylene glycol (PEG) or polyethylene oxide (PEO)) separation tests by flowing them through the top of the membrane under pressure of 25 psi (1.72 bar) on the liquid side. The concentration of the neutral solute was measured by a total organic carbon analyzer (TOC ASI-5000A, Shimadzu Corporation, Japan). The measured feed solution concentration (C _f ) and permeate concentration (C _p ) were used to calculate the effective solute removal factor R (%).

In this study, solutions containing 200 ppm of different molecular weight PEG or PEO were used as neutral solutes for the characterization of membrane pore size and pore size distribution. The relationship between the Stokes radius (r _s , nm) and molecular weight (M _w , g mol ⁻¹ ) of these neutral solutes can be expressed as follows:
In the case of PEG r = 16.73 × 10 ⁻¹² × M ^0.557 (3)
In the case of PEO r = 10.44 × 10 ⁻¹² × M ^0.587 (4)

From equations (3) and (4), the radius (r) of the virtual solute at a given M _w can be calculated. Next, the average effective pore size and pore size distribution are obtained according to conventional solute transport approaches by ignoring the effects of steric and hydrodynamic interactions between the solute and the membrane pores, The mean effective pore radius (μ _ρ ) and geometric standard deviation (σ _p ) are μ _s (geometric mean radius of the solute at R = 50%) and σ _g (R = 84.13% above R = 50%). It may be assumed r _s is the same as the geometric standard deviation), which is defined as the ratio of the at. Therefore, based on the mu _[rho and sigma _p, pore size distribution of the membrane can be represented as a probability density function of the following:

  Table 2 shows the PWP and pore size characteristics of UF membranes made from unsulfonated and directly sulfonated PPSU materials. It is interesting to note that the PWP of these membranes follows the following order: unsulfonated PPSU> sPPSU (2.5 mol% DCDPS)> sPPSU (5 mol% DCDPS). Non-sulfonated PPSU membranes are highly hydrophobic but have many macrovoids with a higher tendency to foul. This may therefore be the reason for having the highest PWP among all membrane substrates. On the other hand, a membrane substrate made from 5 mol% DCDPS polymer provides a lower PWP than a membrane substrate containing 2.5 mol% sulfonated monomer. This phenomenon is due to the fact that the former has a higher degree of water-induced swelling than the latter.

  The MWCO of the as-cast film is in the following order: sPPSU (2.5 mol% DCDPS)> non-sulfonated PPSU> sPPSU (5 mol% DCDPS). MWCO in 2.5 mol% sPPSU is higher than unsulfonated PPSU because its sulfonic acid group causes delayed demixing, resulting in a larger pore size. However, the MWCO at 5 mol% sPPSU is smaller than other membranes due to the effect of greater swelling behavior in highly sulfonated materials. These results suggest that membranes made of directly sulfonated materials that are sulfonated to some extent can be developed for UF membranes because they have good PWP and antifouling properties with a high porosity and interconnected pore structure It shows that the nature is high.

Example 4: Mechanical strength properties of PPSU, sPPSU 2.5% and sPPSU 5% membranes Table 3 summarizes the mechanical strength of the produced UF membranes. While the Young's modulus decreases, the elongation at break increases as the degree of sulfonation of the membrane substrate increases. In the case of sulfonated PPSU with 5 mol% sDCDPS, this indicates a lower mechanical strength. The produced UF membrane was soaked in a 50/50 wt% mixture of glycerol / water for 2 days and then dried in air before performing mechanical testing. The mechanical properties of the membrane substrate were then measured with an Instron 5542 tensile tester. The flat membrane was cut into stripes with a width of 5 mm and clamped at both ends with an initial gauge length of 25 mm and a test speed of 10 mm / min. At least three stripes were tested for each casting condition in order to obtain an average value of tensile stress, elongation at break and Young's modulus of the film.

List of references

  The disclosures of the documents cited herein are incorporated by reference.

Claims (10)

Representing a sponge-like and macrovoid-free structure, comprising at least one membrane substrate layer (S) comprising at least one partially sulfonated polyethersulfone polymer (P1) as a single film-forming polymer material In the ultrafiltration membrane, the polymer (P1) contains non-sulfonated and sulfonated repeating units, and in the partially sulfonated polyethersulfone polymer (P1) , 0.5 to 4.5 mol% The monomer component or repeating unit of the polymer has at least one sulfonate group;
The partially sulfonated polyethersulfone polymer (P1) is a polyarylene ethersulfone polymer, and the repeating unit has the general formula

(Where
Ar represents a divalent arylene residue,
At least one monomer unit selected from M1 and M2 is sulfonated and optionally and independently of one another, the aromatic rings contained in M1 and M2 can be further substituted)
Of monomer units;
And the partially sulfonated polyethersulfone polymer (P1) has the general formulas M1a and M2a

Wherein Ar is as defined above and Hal is F, Cl, Br or I.
A monomer of the general formula M1b and M2b

Wherein Hal and Ar are as defined above and n and m are independently 0, 1 or 2, provided that n and m are not 0 at the same time.
And at least one sulfonated monomer, obtained by the polymerization,
The ultrafiltration membrane, wherein the base material layer (S) has a layer thickness in the range of 30 to 400 μm .   The membrane according to claim 1, wherein the partially sulfonated polyethersulfone polymer (P1) is a block copolymer or a random copolymer. The partially sulfonated polyethersulfone polymer (P1) has the formula (1)

Non-sulfonated repeating units of formula (2)

The membrane according to claim 1, comprising a sulfonated repeating unit of   The membrane according to claim 3, wherein the sulfonated repeating unit is contained in a molar ratio of 1 to 3.5 mol% based on the total number of moles of the repeating units (1) and (2). The polymer P1 has a Mw in the range of 50,000 to 150,000 g / mol as measured by gel permeation chromatography (GPC) in N-dimethylacetamide (DMAc). The membrane according to any one of the preceding items. 6. A membrane according to claim 5, wherein the polymer P1 has a Mw in the range of 70,000 to 100,000 g / mol. Before Kimoto material layer (S) has a layer thickness in the range of 50 to 250 [mu] m, the film according to any one of claims 1 to 6. 8. A process for producing a membrane according to any one of claims 1 to 7, comprising at least one partially sulfonated polyethersulfone polymer as defined in any one of claims 1 to 6. Producing at least one substrate layer (S) by applying a polymer solution comprising (P1),
The polymer content of the polymer solution is in the range of 10 to 24% by mass; and the polymer solution is N-methylpyrrolidone (NMP), N-dimethylacetamide (DMAc), dimethyl sulfoxide (DMSO), dimethylformamide ( DMF), triethyl phosphate, tetrahydrofuran (THF), 1,4-dioxane, methyl ethyl ketone (MEK), or combinations thereof; additionally ethylene glycol, diethylene glycol, polyethylene glycol, Containing at least one further additive selected from glycerol, methanol, ethanol, isopropanol, polyvinylpyrrolidone, or combinations thereof, wherein said additive comprises the total mass of the polymer solution The method, which is contained in the polymer solution in the range of 0 to 30% by mass, and wherein the at least one substrate layer (S) is produced by applying a phase inversion method using water as a coagulation bath . An ultrafiltration method using the membrane according to any one of claims 1 to 7 . Use of the membrane according to any one of claims 1 to 7 as a substrate for producing a membrane compatible with other applications such as FO or NF.

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