A MEMBRANE (M) COMPRISING A SULFONATED POLY(ARYLENE ETHER SULFONE) POLYMER (SP) AND A NON-SULFONATED POLY(ARYLENE SULFONE) POLYMER (P)

Abstract

The present invention relates to a membrane (M) comprising a sulfonated poly(arylene ether sulfone) polymer (sP) and a non-sulfonated poly(arylene sulfone) polymer (P), to a method for the preparation of the membrane (M) and to the use of the membrane as nanofiltration membrane. Further, the present invention relates to a monolithic film (F) comprising a sulfonated poly(arylene ether sulfone) polymer (sP) and a non-sulfonated poly(arylene sulfone) polymer (P), wherein the monolithic film has a contact angle of 63 to 77.

Claims

1.-14. (canceled)

15. A membrane comprising a blend of (A) a sulfonated poly(arylene ether sulfone) polymer and (B) a non-sulfonated poly(arylene sulfone) polymer, wherein the membrane has a minimal pore diameter of <5 nm and a pure water permeation of >50 kg/(h m.sup.2 bar) and wherein the membrane is a nanofiltration membrane, wherein the average pore diameter is determined by gas adsorption-desorption experiments with nitrogen and Harkins-Jura analysis and rejection of diluted poly(ethylene oxide) solutions with a molecular weight of 8 000 g/mol or diluted rose Bengal with a molecular weight of 1 017 g/mol, and the pure water permeation is determined using a pressure cell with a diameter of 74 mm using ultrapure water (salt-free water, filtered by a Millipore UF-system) at 23 C. and 1 bar water pressure, wherein the membrane comprises from 15 to 80% by weight of the sulfonated poly(arylene ether sulfone) polymer, based on the total weight of the membrane, and wherein the sulfonated poly(arylene ether sulfone) polymer comprises units of formula (III) ##STR00011## and/or formula (IV) ##STR00012##

16. The membrane according to claim 15, wherein the non-sulfonated poly(arylene sulfone) polymer comprises units of formula (II) ##STR00013## where t and q: are each independently 0, 1, 2 or 3, Q, T and Y: are each independently a chemical bond or a group selected from O, S, SO.sub.2, (SO), (CO), NN and CR.sup.aR.sup.b wherein R.sup.a and R.sup.b are each independently a hydrogen atom or a C.sub.1-C.sub.12-alkyl, C.sub.1-C.sub.12-alkoxy or C.sub.6-C.sub.18-aryl group, and where at least one of Q, T and Y is SO.sub.2 and Ar, Ar.sup.1: are each independently an arylene group having from 6 to 18 carbon atoms.

17. The membrane according to claim 16, wherein the non-sulfonated poly(arylene sulfone) polymer is a poly(ether sulfone) and comprises units of formula (lk) ##STR00014##

18. The membrane according to claim 15, wherein the membrane is a porous membrane.

19. The membrane according to claim 15, wherein the membrane is asymmetric.

20. A method for the preparation of the membrane according to claim 15, wherein the method comprises the steps: a) providing a solution which comprises the sulfonated poly(arylene ether sulfone) polymer according to component (A), the non-sulfonated poly(arylene sulfone) polymer according to component (B), at least one pore forming additive and at least one solvent, and b) separating the at least one pore forming additive and the at least one solvent from the solution to obtain the membrane, wherein the at least one pore forming additive is poly(ethylene oxide).

21. The method according to claim 20, wherein the at least one solvent is selected from the group consisting of N-alkyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-butyl-2-pyrrolidone and N-tert.-butyl-2-pyrrolidone, 2-pyrrolidone, N,N-dimethylacetamide, dimethylsulfoxide, dimethylformamide, N,N-dimethyl-2-hydroxypropan amide, N,N-diethyl-2-hydroxypropan amide, -valerolactone, dihydrolevoglucosenone, methyl 5-(dimethylamino)-2-methyl-5-oxopentanoate and sulfolane.

22. The method according to claim 20, wherein step b) comprises the following steps: b-1) casting the solution provided in step a) to obtain a film of the solution, b-2) immersing the film of the solution into at least one protic polar solvent, wherein the sulfonated poly(arylene ether sulfone) polymer and the non-sulfonated poly(arylene sulfone) polymer comprised in the film of the solution are at least partly separated from the at least one pore forming additive and the at least one solvent comprised in the film of the solution to obtain a membrane (M1) which is in the form of a film, and b-3) washing the membrane (M1) with water, wherein the sulfonated poly(arylene ether sulfone) polymer and the non-sulfonated poly(arylene sulfone) polymer comprised in the membrane (M1) are completely separated from the at least one pore forming additive and the at least one solvent comprised in the membrane (M1) to obtain the membrane.

23. The method according to claim 22, wherein the at least one protic polar solvent is water.

24. The method according to claim 22, wherein step b-1) is carried out at a temperature in the range of 40 to 80 C.

25. A monolithic film comprising (A) a sulfonated poly(arylene ether sulfone) polymer and (B) a non-sulfonated poly(arylene sulfone) polymer, wherein the monolithic film has a contact angle of 63 to 77, wherein the contact angle is determined by time-resolved automated image analysis at 23 C. placing 8 to 10 drops of deionized water on the sample, and wherein the monolithic film comprises from 15 to 80% by weight of component (A) and from 20 to 85% by weight of component (B), each based on the total weight of the monolithic film.

Description

EXAMPLES

Components Used

[0200] sP (component (A)): sulfonated poly(ether sulfone)

Synthesis of the Sulfonated Poly(Ether Sulfone)

1) Synthesis of the Poly(Ether Sulfone)

[0201] In a 4 liter glass reactor fitted with a thermometer, a gas inlet tube and a Dean-Stark-trap, 574.34 g (2.00 mol) of 4,4-dichlorodiphenylsulfone (DCDPS), 475.53 g (1.90 mol) of 4,4-dihydroxydiphenylsulfone (DHDPS), 18.621 g (0.10 mol) of 4,4-biphenol and 297.15 g (2.15 mol) of potassium carbonate with a volume average particle size of 33.2 m are suspended in 1050 mL NMP (N-methyl-2-pyrrolidone; CAS 872-50-4) in a nitrogen atmosphere. The mixture is heated to 190 C. within one hour. In the following, the reaction time shall be understood to be the time during which the reaction mixture is maintained at 190 C. The water formed in the reaction is continuously removed by distillation. The evaporated solvent is replaced. After a reaction time of 7 hours, the reaction is stopped by the addition of 1950 mL NMP and cooling down to room temperature (within one hour). The potassium chloride formed in the reaction is removed by filtration. The obtained poly(ether sulfone) solution is then precipitated in water, the resulting poly(ether sulfone) beads are separated and then extracted with hot water (85 C.) for 20 h. Then the beads are dried at 120 C. for 24 h at reduced pressure (<100 mbar).

[0202] The presence of the 4,4-biphenol derived units in the copolymer is verified by 1H-NMR spectroscopy. The obtained poly(ether sulfone) has a glass transition temperature (T.sub.G) of 230.8 C., a viscosity number of 82.1 mL/g, a molecular weight M.sub.W (GPC in THF, PS standard) of 74 450 g/mol and a polydispersity M.sub.W/M.sub.N of 3.6.

2) Synthesis of the Sulfonated Poly(Ether Sulfone)

[0203] From a reservoir sulfuric acid (96%) is provided to a reaction vessel in an amount needed to provide a solution with the targeted sulfonated poly(ether sulfone) concentration of 8% by weight. The temperature of the sulfuric acid is set to the sulfonation temperature. 50 kg of the above-obtained poly(ether sulfone) is dosed to the mixture within 10 to 30 minutes. The reaction mixture is stirred for another 90 minutes to completely dissolve the poly(ether sulfone). The reaction mixture is thereafter stirred for another 90 minutes. In a reservoir equipped with a stirrer and with a wall temperature of 15 C. a liquid L1 is prepared from 3 125 L deionized water and nitric acid so that the nitric acid concentration in the liquid L1 is 0.27% by weight, based on the liquid L1.

[0204] As dynamic inline mixing device a one-stage rotor-stator tooth rim dispersion machine with a concave rotor is used (Cavitron CD1010, with a cone mixing system; Verfahrenstechnik v. Hagen & Funke GmbH, Sprockhvel, Germany). The dynamic inline mixing device functions as a pump which due to operating it at maximum rotational speed of up to 12 000 rpm. It draws the liquid L1 from the reservoir, whereby the inline mixing device operates in recirculation loop operation. While the three-way valve is set to the sulfuric acid reservoir, the gear pump is started to pump the sulfuric acid to the dynamic inline mixer and flushing the piping while doing this. After the connecting pipes are purged by the sulfuric acid, the respective sulfonated poly(ether sulfone) solution is fed to the dynamic inline mixing device by opening the three-way valve towards the reaction vessel containing the sulfonated poly(ether sulfone) solution and pumping it into the dynamic inline mixer. Upon the contacting of the respective sulfonated poly(ether sulfone) solution with the liquid L1 a suspension is obtained. The suspension is recirculated into the reservoir of liquid L1 whereby its solid content increased continually. To avoid settling, the suspension is stirred in the reservoir. The liquid L1 and the suspension respectively are passed through the dynamic inline mixing device in an amount of about 75 L/min. The temperature of the suspension in the reservoir is monitored. In course of the process the temperature of the suspension rises by between 30 to 35 C. The suspension is recirculated until the respective sulfonated poly(ether sulfone) solution is used up. Thereafter the pipes are purged with the sulfuric acid.

[0205] The suspension is filtered through a Nutsche, whereby 1 bar pressure is applied. A filter with a nominal pore size of 10 m is used. The filter cake is washed with about 800 L of deionized water with a temperature of about 40 C. per washing is used. The washing is interrupted as soon as the filtrate water has a pH of 4 or higher. Typically, not more than six washings are carried out. Thereafter, the obtained respective sulfonated poly(ether sulfone) is dried in the Nutsche under vacuum at 55 to 60 C. until a residual water content of below 2% by weight, based on the weight of the sulfonated poly(ether sulfone), is obtained.

[0206] The sulfonated poly(ether sulfone) polymer has a viscosity number of 86.3 mL/g, a molecular weight Mw (GPC in THF, PS standard) of 72 400 g/mol, a polydispersity of M.sub.W/M.sub.N=3.6 and an Ion Exchange Capacity IEC of 0.210 meq/g. [0207] P (component (B)): poly(ether sulfone); Ultrason E 6020 P; BASF SE; Viscosity number: 81 cm.sup.3/g (determined according to ISO 307; in 0.01 g/mL phenol/1,2-orthodichlorobenzene, 1:1 solution); Glass transition temperature T.sub.G: 225 C. (determined according to ISO 11357-1/-2, DSC, 10 C./min); Molecular weight Mw: 75 000 g/mol (determined by GPC in THF, PS standard); Polydispersity M.sub.W/M.sub.N: 3.4 [0208] PEO 1 (component (C1)): poly(ethylene oxide); Pluriol 200 E; BASF SE; Average molecular weight M.sub.w: 200 g/mol (calculated from the OH numbers according to DIN 53240) [0209] PEO 2 (component (C2)): poly(ethylene oxide); Pluriol 8000 E; BASF SE; Average molecular weight M.sub.w: 7 510 g/mol (calculated from GPC in water with 0.01 mol phosphate buffer pH 7.4, TSKgel GMPWXL column, Tosoh Bioscience with poly(ethylene oxide) standard 106-1 522 000 g/mol); Polydispersity M.sub.W/M.sub.N: 1.1; solution viscosity characterised by the K-value of 28.8 (determined according to the method of Fikentscher (Fikentscher, Cellulosechemie 13, 1932 (58))) [0210] PEO 3 (component (C3)): poly(ethylene oxide); Pluriol 9000 E; BASF SE; Average molecular weight M.sub.W: 10 800 g/mol (calculated from GPC in water with 0.01 mol phosphate buffer pH 7.4, TSKgel GMPWXL column, Tosoh Bioscience with poly(ethylene oxide) standard 106-1 522 000 g/mol); Polydispersity M.sub.W/M.sub.N: 1.2; solution viscosity characterised by the K-value of 33 (determined according to the method of Fikentscher (Fikentscher, Cellulosechemie 13, 1932 (58)))

General Procedures

Pure Water Permeation (PWP)

[0211] The pure water permeation (PWP) of the membranes is tested using a pressure cell with a diameter of 74 mm using ultrapure water (salt-free water, filtered by a Millipore UF-system) at 23 C. and 1 bar water pressure. The pure water permeation (PWP) is calculated as follows (equation 1):

[00002]$\begin{array}{cc}\mathrm{PWP}=\frac{m}{APt}& \left(1\right)\end{array}$ [0212] PWP: pure water permeance [kg/bar h m.sup.2] [0213] m: mass of permeated water [kg] [0214] A: membrane area [m.sup.2] [0215] P: pressure [bar] [0216] t: time of the permeation experiment [h].

[0217] In a subsequent test, solutions of rose bengal (Sigma-Aldrich, 1 017 g/mol; 35 M in ultra-pure water) and poly(ethylene oxide) (Pluriol 8000 E, 0.1 wt % in ultra-pure water) are used as feed to be filtered by the membrane at a pressure of 0.2 bar and rejection (MWCO %) is calculated by equation (2) in which C.sub.F and C.sub.P represent the concentrations in initial feed and in permeate, respectively. For poly(ethylene oxide)-standard (MWCO 1) the concentrations of the feed and permeate are determined by GPC-measurement (refractive index detector) while for rose bengal (MWCO 2) the concentrations are recorded on a Spectroquant Nova 60 (Merck KGA, Darmstadt, Germany) UV-vis spectrophotometer at a wavelength of 550 nm.

[00003]$\begin{array}{cc}\mathrm{MWCO}=\left(1-\frac{C_P}{C_F}\right)100\left[\%\right]& \left(2\right)\end{array}$ [0218] MWCO 1: feed PEO 8000 [0219] MWCO 2: feed rose bengal

[0220] According to Matsuyama et. al (Ind. Eng. Chem. Res. 2017, 56, 11302) PEO 8000 has a calculated stokes radius of 2.5 nm.

Viscosity

[0221] The polymer solution viscosity is measured with a Brookfield Viscometer DV-I Prime (Brookfield Engineering Laboratories, Inc. Middleboro, USA) with RV 6 spindle at 60 C. with 20 rpm.

Turbidity

[0222] The polymer solution turbidity is measured at 60 C. with a turbidimeter 2100AN (Hach Lange GmbH, Dusseldorf, Germany) employing a filter of 860 nm and expressed in nephelometric turbidity units (NTU).

Contact Angle

[0223] The contact angle (CA) of the polymer films is measured at 23 C. by placing 8 to 10 drops of deionized water with a volume of approximately 2 L on the sample. The contact angle is determined by time-resolved automated image analysis by Krss DSA100 (A. KRSS Optronic GmbH, Hamburg, Germany).

Film Thickness

[0224] The film thickness is measured with a Mitutoyo ID-C112XB (Mitutoyo Corporation, Kawasaki, Japan).

PEO Share

[0225] The poly(ethylene oxide) content of the membranes (PEO share) is determined by dissolving the membrane sample in deuterated chloroform (CDCl.sub.3) and measuring proton nuclear magnetic resonance spectroscopy (1H-NMR) with a Bruker Avance III 400 (Bruker Corporation, Billerica, USA). The signal at 3.7 ppm is analyzed to obtain the overall PEO share.

BET Surface Assessment

[0226] Solvent exchanged and dried membrane samples are used for Brunauer-Emmet-Teller (BET) surface assessment. The wet membrane samples are stored for 12 h subsequently in water/ethanol (1:1 wt/wt), water/ethanol (1:2 wt/wt), ethanol/n-hexane (1:1 wt/wt) and finally n-hexane before drying at 60 C. under vacuum.

[0227] The BET surface is determined by gas-adsorption-desorption (GAD) experiments with nitrogen by 5-point method with ASAP 2420 (Fa. Micromeritics, Norcross, USA). The samples are activated at 130 C. for 15 min before measurement.

Preparation of Monolithic Films

Comparative examples C1-F and C4-F

[0228] As given in table 1, into a three-neck flask equipped with a magnetic stirrer 20 g sulfonated poly(ether sulfone) polymer (sP) (component (A)) or 20 g non-sulfonated poly(ether sulfone) polymer (P) (component (B)), respectively, and 80 g NMP (component (D)) are added. The mixture is heated under gentle stirring at 60 C. until a homogeneous clear viscous solution is obtained. The solution is degassed overnight at room temperature. After that, the solution is reheated at 60 C. for 2 hours and casted onto a glass plate with a casting knife (300 microns) at 60 C. using an Erichsen Coating machine (Coatmaster 510, Erichsen GmbH & Co KG, Hemer, Germany) operating at a speed of 5 mm/s. The solvent is evaporated at 50 C. at 10 mbar overnight and the dried film transferred on the glass plate into a water bath at 25 C. for 10 minutes. After the film is detached from the glass plate, it is subjected extraction with water at 80 C. (160 liters/hours) overnight.

Inventive Examples I2-F and I3-F

[0229] As given in table 1, into a three-neck flask equipped with a magnetic stirrer sulfonated poly(ether sulfone) polymer (sP) (component (A)) and non-sulfonated poly(ether sulfone) polymer (P) (component (B)) in the amounts given in table 1, and 80 g NMP (component (D)) are added. The mixture is heated under gentle stirring at 60 C. until a homogeneous clear viscous solution (SF) is obtained. The solution (SF) is degassed overnight at room temperature. After that, the solution (SF) is reheated at 60 C. for 2 hours and casted onto a glass plate with a casting knife (300 microns) at 60 C. using an Erichsen Coating machine (Coatmaster 510, Erichsen GmbH & Co KG, Hemer, Germany) operating at a speed of 5 mm/s. The solvent is evaporated at 50 C. at 10 mbar overnight and the dried film transferred on the glass plate into a water bath at 25 C. for 10 minutes. After the film is detached from the glass plate, it is subjected extraction with water at 80 C. (160 liters/hours) overnight.

[0230] The viscosity, thickness and contact angle of the resulting films are determined (table 1).

TABLE-US-00001 TABLE 1 (A) (B) (D) Viscosity Thickness Contact angle Example [g] [g] [g] [Pas] [m] [] C1-F 20 80 0.77 29 78.4 I2-F 4 16 80 0.87 38 76.3 I3-F 15 5 80 0.89 36 65.1 C4-F 20 80 0.86 28 61.7

[0231] By solution blending sulfonated poly(ether sulfone) (component (A)) with non-sulfonated poly(ether sulfone) (component (B)) monolithic films having contact angles between 63 and 77 and defined hydrophilicity can be obtained.

Preparation of Membranes

Comparative Examples C1-M and C2-M

[0232] As given in table 2, into a three-neck flask equipped with a magnetic stirrer 25 g non-sulfonated poly(ether sulfone) (component (B)), 15 g poly(alkylene oxide) (Pluriol 200 or 9000 E; component (C)) and 60 g of NMP (component (D)) are added. The mixture is heated under gentle stirring at 60 C. until a homogeneous clear viscous solution (S) is obtained. The solution (S) is degassed overnight at room temperature. After that, the solution (S) is reheated at 60 C. for 2 hours and casted onto a glass plate with a casting knife (300 microns) at 60 C. using an Erichsen Coating machine (Coatmaster 510, Erichsen GmbH & Co KG, Hemer, Germany) operating at a speed of 5 mm/s to obtain a film of the solution (S). The film of the solution (S) is allowed to rest for 30 seconds before immersion in a water-based coagulation bath (60% by weight water/40% by weight NMP) at 25 C. for 10 minutes to obtain a membrane (M1). After the membrane (M1) is detached from the glass plate, the membrane (M1) is carefully transferred into a water bath for 12 h. Subsequently the membrane (M1) is washed with water at 60 C. three times to obtain the membrane (M).

Comparative Examples C3-M and C4-M

[0233] As given in table 2, into a three-neck flask equipped with a magnetic stirrer 25 g sulfonated poly(ether sulfone) polymer (component (A)), 15 g poly(alkylene oxide) (Pluriol 200 or 9000 E; component (C)) and 60 g of NMP (component (D)) are added. The mixture is heated under gentle stirring at 60 C. until a homogeneous clear viscous solution (S) is obtained. The solution (S) is degassed overnight at room temperature. After that, the solution (S) is reheated at 60 C. for 2 hours and casted onto a glass plate with a casting knife (300 microns) at 60 C. using an Erichsen Coating machine (Coatmaster 510, Erichsen GmbH & Co KG, Hemer, Germany) operating at a speed of 5 mm/s to obtain a film of the solution (S). The film of the solution (S) is allowed to rest for 30 seconds before immersion in a water-based coagulation bath (60% by weight water/40% by weight NMP) at 25 C. for 10 minutes to obtain a membrane (M1). After the membrane (M1) is detached from the glass plate, the membrane (M1) is carefully transferred into a water bath for 12 h. Subsequently the membrane (M1) is washed with water at 60 C. three times to obtain the membrane (M).

Inventive Examples I7-M to I12-M

[0234] Into a three-neck flask equipped with a magnetic stirrer sulfonated poly(ether sulfone) polymer (component (A)) and non-sulfonated poly(ether sulfone) (component (B)) in the amounts given in table 2, 15 g poly(alkylene oxide) (Pluriol 200 or 9000 E; component (C)) and 60 g of NMP (component (D)) are added. The mixture is heated under gentle stirring at 60 C. until a homogeneous clear viscous solution (S) is obtained (step a)). The solution (S) is degassed overnight at room temperature. After that, the solution (S) is reheated at 60 C. for 2 hours and casted onto a glass plate with a casting knife (300 microns) at 60 C. using an Erichsen Coating machine (Coatmaster 510, Erichsen GmbH & Co KG, Hemer, Germany) operating at a speed of 5 mm/s to obtain a film of the solution (S) (step b-1)). The film of the solution (S) is allowed to rest for 30 seconds before immersion in a water-based coagulation bath (60% by weight water/40% by weight NMP) at 25 C. for 10 minutes to obtain a membrane (M1). After the membrane (M1) is detached from the glass plate, the membrane (M1) is carefully transferred into a water bath for 12 h. Subsequently the membrane (M1) is washed with water at 60 C. three times to obtain the membrane (M).

[0235] The compositions and properties of the solutions (S), as well as of the prepared membranes (M), are shown in table 2.

TABLE-US-00002 TABLE 2 (A) (B) (C1) (C3) (D) Viscosity Turbidity PWP MWCO 1 MWCO 2 PEO share BET Example [g] [g] [g] [g] [g] [Pas] [NTU] [kg/hm.sup.2bar] [%] [%] [% by weight] [m.sup.2/g] C1-M 25 15 60 6.5 0.63 0 0.4 11.1 C2-M 25 15 60 13.1 1.01 10 11.5 26.3 I7-M 5 20 15 60 6.4 0.88 60 80.6 92.1 0 40.6 I8-M 7.5 17.5 15 60 6.5 0.97 190 88.7 87.3 0.1 48.6 I9-M 7.5 17.5 15 60 12.6 1.36 180 99.7 86.6 5.1 69.3 I10-M 10 15 15 60 6.7 1.53 155 100 97.2 0 62.6 I11-M 12.5 12.5 15 60 7.0 1.27 160 100 89.7 0.1 79.8 I12-M 18.75 6.25 15 60 6.8 1.55 54 100 99.4 0 141.6 C3-M 25 15 60 6.8 1.96 23 99.8 99.1 0.1 172.1 C4-M 25 15 60 14.8 2.51 30 100 99.5 1.5 209.6

[0236] As can be seen from table 2, the inventive membranes show all a high pure water permeation of >50 kg/h m.sup.2 bar and a high rejection MWCO 1 and MWCO 2 of at least 80%. Further, the solutions show low NTU values <1.6.

[0237] FIG. 1 shows a cross-section of the membrane of inventive example 19-M and FIG. 2 shows a cross-section of the membrane of comparative example C2-M (1500 magnification). As can be seen from the figures, the membrane according to the invention shows a well-established nano porous filtration layer with no defects or macrovoids. The membrane according to comparative example C2-M shows numerous macrovoids and defects which could partially penetrate the filtration layer on the top.

Comparative examples C5-M and C6-M

[0238] As shown in table 3, into a three-neck flask equipped with a magnetic stirrer non-sulfonated poly(ether sulfone) (component (B)) in the amounts given, poly(alkylene oxide) (Pluriol 200; component (C)) in the amounts given and NMP (component (D)) in the amounts given are added. The mixture is heated under gentle stirring at 60 C. until a homogeneous clear viscous solution (S) is obtained. The solution (S) is degassed overnight at room temperature. After that, the solution (S) is reheated at 60 C. for 2 hours and casted onto a glass plate with a casting knife (300 microns) at 60 C. using an Erichsen Coating machine (Coatmaster 510, Erichsen GmbH & Co KG, Hemer, Germany) operating at a speed of 5 mm/s to obtain a film of the solution (S). The film of the solution (S) is allowed to rest for 30 seconds before immersion in a water-based coagulation bath (60% by weight water/40% by weight NMP) at 25 C. for 10 minutes to obtain a membrane (M1). After the membrane (M1) is detached from the glass plate, the membrane (M1) is carefully transferred into a water bath for 12 h. Subsequently the membrane (M1) is washed with water at 60 C. three times to obtain the membrane (M).

Inventive examples I13-M to I17

[0239] As shown in table 3, into a three-neck flask equipped with a magnetic stirrer sulfonated poly(ether sulfone) polymer (component (A)), non-sulfonated poly(ether sulfone) (component (B)), poly(alkylene oxide) (Pluriol 200; component (C)) and a solvent (component (D)) in the amounts given are added. The mixture is heated under gentle stirring at 60 C. until a homogeneous clear viscous solution (S) is obtained. The solution (S) is degassed overnight at room temperature. After that, the solution (S) is reheated at 60 C. for 2 hours and casted onto a glass plate with a casting knife (300 microns) at 60 C. using an Erichsen Coating machine (Coatmaster 510, Erichsen GmbH & Co KG, Hemer, Germany) operating at a speed of 5 mm/s to obtain a film of the solution (S). The film of the solution (S) is allowed to rest for 30 seconds before immersion in a water-based coagulation bath at 25 C. for 10 minutes to obtain a membrane (M1). After the membrane (M1) is detached from the glass plate, the membrane (M1) is carefully transferred into a water bath for 12 h. Subsequently the membrane (M1) is washed with water at 60 C. three times to obtain the membrane (M).

[0240] The properties of the solutions are shown in table 3, the properties of the membranes are shown in table 4.

TABLE-US-00003 TABLE 3 (A) (B) (C1) (D) Viscosity Turbidity Example [g] [g] [g] [g] Solvent (D) [Pas] [NTU] Coagulation bath C5-M 20 12 68 NMP 1.2 0.60 60% by weight water/ 40% by weight NMP C6-M 30 18 52 NMP 28.3 0.75 60% by weight water/ 40% by weight NMP I13-M 8 12 12 68 NMP 1.4 0.98 60% by weight water/ 40% by weight NMP I14-M 12 18 18 52 NMP 31.9 1.39 60% by weight water/ 40% by weight NMP I15-M 10 15 15 60 AMD (N,N- 23.7 2.01 60% by weight water/ dimethyl-2- 40% by weight AMD hydroxy- propanamide; CAS 35123-06-9) I16-M 10 15 15 60 TBP (N-tert.- 25.6 1.90 60% by weight water/ butyl-2- 40% by weight TBP pyrrolidone; CAS 20687-53-0) I17-M 10 15 15 60 GVL (- 9.6 2.3 water valerolactone; CAS 108-29-2)

TABLE-US-00004 TABLE 4 PWP [kg/ MWCO MWCO PEO share BET Example hm.sup.2bar] 1 [%] 2 [%] [% by weight] [m.sup.2/g] C5-M 0 0.2 12.9 C6-M 0 0.4 8.6 I13-M 140 95.0 92.45 0 42.0 I14-M 62 100 97.8 0 67.8 I15-M 120 100 98.84 0 71.5 I16-M 80 99.9 98.96 0 60.5 I17-M 50 99.7 97.05 0.1 47.4

[0241] As can be seen from tables 3 and 4, the inventive membranes show all a high pure water permeation of 50 to 140 kg/h m.sup.2 bar and a high rejection MWCO 1 and MWCO 2 of at least 85% for PE08000 and rose Bengal. The BET surfaces of the inventive membranes account for more than 30 m.sup.2/g. The PEO shares in the membrane matrix of less than 0.2% by weight indicate that the membrane hydrophilicity originates from the hydrophilicity of the sP/P matrix having contact angles of 63 to 77. The membrane preparation can be carried out with different concentrations of sP/P (20-30 wt %) and PEO as pore former (12-18 wt %) and also with different solvents (NMP, AMD, TBP and GVL).