Block copolymers

Abstract

Block copolymer comprising polyarylene ether blocks and polyalkylene oxide blocks, wherein said block copolymer comprises at least two polyalkylene oxide blocks that are endcapped with different endcapping groups.

Claims

1. A block copolymer composition, comprising: at least two different sets of individual polymers of structure AB and/or ABA, wherein B is a polyethersulfone block of formula IIk: ##STR00006## wherein D is a direct bond; and A represents at least two different polyalkylene oxide blocks designated A and A directly covalently bonded to a common polyarylene ether block structure with an ether bond; wherein a set of polymers have the same polyalkylene ether blocks A or A, and the at least two different polyalkylene oxide blocks are each of formula
R.sup.x(OCH.sub.2CHR.sup.B).sub.kO(1), wherein R.sup.x is an aliphatic or aromatic group having from 1 to 20 carbons, x is an index number which identifies different R groups, with the proviso that at least two different R groups having different x numbers are present, R.sup.B is hydrogen, an aliphatic group or an aromatic group, k is a number from 1 to 500.

2. The block copolymer composition according to claim 1, wherein each R.sup.x group is an alkyl group.

3. The block copolymer composition according to claim 1, wherein the different sets of block copolymer comprise identical polyalkylene oxide blocks of formula
(OCH.sub.2CHR.sup.B).sub.kO and different R.sup.x groups.

4. The block copolymer composition according to claim 1, wherein R.sup.B is H.

5. The block copolymer composition according to claim 1, wherein x is 1 and 2 and R.sup.1 is a C.sub.16 alkyl and R.sup.2 is a C.sub.18 alkyl.

6. The block copolymer composition according to claim 1, wherein a molar content of each different polyalkylene block of formula I is at least 5 mol % relative to a total molar amount of all polyalkylene oxide blocks of formula I present in the block copolymer composition.

7. The block copolymer composition according to claim 1, comprising at least two different sets of individual polymer molecules of formula III ##STR00007## wherein R.sup.x is an aliphatic or aromatic group, x is an index number which identifies different R groups, with the proviso that at least two different x numbers are present, k is a number from 1 to 500, n is a number from 4 to 150.

8. A process for making the block copolymer composition according to claim 1, comprising reacting aromatic bishalogeno sulfonyl compounds with aromatic biphenols or salts thereof in the presence of at least one base and in the presence of at least two different polyalkyleneoxide compounds comprising different groups of formula (I).

9. A membrane comprising the block copolymer composition according to claim 1.

10. The membrane according to claim 9, wherein the membrane is suitable for ultrafiltration, microfiltration, reverse osmosis, forward osmosis, or nanofiltration.

11. The membrane according to claim 9, wherein the membrane is suitable for water treatment applications, treatment of industrial or municipal waste water, desalination of sea or brackish water, dialysis, plasmolysis, or food processing.

12. The membrane according to claim 9, wherein an amount of the block copolymer composition is from 0.01% by weight to 100% by weight of the membrane.

13. The membrane according to claim 12, wherein the membrane is an ultrafiltration (UF) membrane, a microfiltration (MF) membrane, a reverse osmosis (RO) membrane, a forward osmosis (FO) membrane or a nanofiltration (NF) membrane.

14. A membrane element comprising multiple membranes according to claim 9.

15. A membrane module comprising multiple membranes according to claim 9.

16. A filtration system comprising multiple membrane modules according to claim 15.

Description

EXAMPLES

Abbreviations

(1) DCDPS 4,4-Dichlorodiphenylsulfone

(2) DHDPS 4,4-Dihydroxydiphenylsulfone

(3) NMP N-methylpyrrolidone

(4) DMAc Dimethylacetamide

(5) PWP pure water permeation

(6) MWCO molecular weight cutoff

(7) The viscosity of copolymers was measured as a 1% by weight solution of the copolymer in NMP at 25 C. according to DIN EN ISO 1628-1.

(8) Copolymers were isolated from their solution by precipitation of solutions of the copolymers in water at room temperature (height of spray reactor 0.5 m, flux: 2.5 l/h). The so obtained beads were then extracted with water at 85 C. for 20 hours (water flow 160 l/h). The beads were then dried to a water content of less than 0.1% by weight.

(9) The molecular weight distribution and the average molecular weight of the copolymers were determined by GPC measurements in DMAc.

(10) GPC-measurements were done using Dimethylacetamide/0.5 wt.-% LiBr as eluent. The concentration of the polymer solution was 4 mg/ml. After filtration (pore size 0.2 m), 100 l of this solution was injected in the GPC system. For the separation 4 different columns (heated to 80 C.) were used (GRAM pre-column, GRAM 30 A, GRAM 1000 A, GRAM 1000 A, separation material: polyester copolymers). The system was operated with a flow rate of 1 ml/min. As detection system a DRI Agilent 1100 was used.

(11) The calibration was done with PMMA-standards with molecular weights (Mn) from 800 to 1820000 g/mol.

(12) Molecular weights of the polymers obtained were determined by comparison of the viscosity obtained according to DIN EN ISO 1628-1 as a 1% by weight solution in NMP.

(13) The content of polyalkyleneoxide in the block copolymer was determined using .sup.1H-NMR in CDCl.sub.3. The signal intensity of resonance signals for H-atoms of polyalkylene groups was compared to the signal intensity of resonance signals for H-atoms of aromatic groups comprised in polyarylene ether blocks. This comparison yields the ratio of polyalkylene oxide to polyarylene ether that can be can be used to calculate the content of polyalkylene oxide in the copolymer by weight.

(14) The glass transition temperature of the products was determined by DSC analysis. All DSC-measurements were done using a DSC 2000 of TA Instruments at a heating rate of 20 k/min. About 5 mg material were placed in an Aluminum vessel and sealed. In the first run, the samples were heated to 250 C., rapidly cooled to 100 C. and then in the second run heated to 250 C. The Tg-values given were determined in the second run.

(15) The results of all measurements are given in table 1.

Preparation of Copolymers

Comparative Example 1: PESU-PEO-Copolymer

(16) In a 4 liter glass reactor fitted with a thermometer, a gas inlet tube and a Dean-Stark-trap, 574.16 g of DCDPS, 490.33 g of DHDPS, 80 g of -methyl,-hydroxy-polyethyleneglykol with a number average molecular mass Mn of 2000 g/mol and 290.24 g of potassium carbonate with a volume average particle size of 32.4 m were suspended in 1053 ml NMP in a nitrogen atmosphere.

(17) The mixture was 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 was maintained at 190 C.

(18) The water that was formed in the reaction was continuously removed by distillation. The solvent level inside the reactor was maintained at a constant level by addition of further NMP.

(19) After a reaction time of six hours, the reaction was stopped by addition of 1947 ml of NMP with a temperature of 23 C. Nitrogen was bubbled through the mixture for one hour with a rate of 20 l/h and the mixture was let to cool to room temperature. The potassium chloride formed in the reaction was removed by filtration.

Comparative Example 2: PESU-PEO-Copolymer

(20) In a 4 liter glass reactor fitted with a thermometer, a gas inlet tube and a Dean-Stark-trap, 574.16 g of DCDPS, 487.83 g of DHDPS, 100 g of -methyl,-hydroxy-polyethyleneglykol with a number average molecular mass Mn of 2000 g/mol and 290.24 g of potassium carbonate with a volume average particle size of 32.4 m were suspended in 1053 ml NMP in a nitrogen atmosphere.

(21) The mixture was 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 was maintained at 190 C.

(22) The water that was formed in the reaction was continuously removed by distillation. The solvent level inside the reactor was maintained at a constant level by addition of further NMP.

(23) After a reaction time of six hours, the reaction was stopped by addition of 1947 ml of NMP with a temperature of 23 C. Nitrogen was bubbled through the mixture for one hour with a rate of 20 l/h and the mixture was let to cool to room temperature. The potassium chloride formed in the reaction was removed by filtration.

Comparative Example 3: PESU-PEO-Copolymer

(24) In a 4 liter glass reactor fitted with a thermometer, a gas inlet tube and a Dean-Stark-trap, 574.16 g of DCDPS, 487.83 g of DHDPS, 210 g of -methyl,-hydroxy-polyethyleneglykol with a number average molecular mass Mn of 4200 g/mol and 290.24 g of potassium carbonate with a volume average particle size of 32.4 m were suspended in 1053 ml NMP in a nitrogen atmosphere.

(25) The mixture was 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 was maintained at 190 C.

(26) The water that was formed in the reaction was continuously removed by distillation. The solvent level inside the reactor was maintained at a constant level by addition of further NMP.

(27) After a reaction time of six hours, the reaction was stopped by addition of 1947 ml of NMP with a temperature of 23 C. Nitrogen was bubbled through the mixture for one hour with a rate of 20 l/h and the mixture was let to cool to room temperature. The potassium chloride formed in the reaction was removed by filtration.

Comparative Example 4: PESU-PEO-Copolymer

(28) In a 4 liter glass reactor fitted with a thermometer, a gas inlet tube and a Dean-Stark-trap, 574.16 g of DCDPS, 487.83 g of DHDPS, 220 g of -stearyl,-hydroxy-polyethyleneglykol with a number average molecular mass Mn of 4400 g/mol and 290.24 g of potassium carbonate with a volume average particle size of 32.4 m were suspended in 1053 ml NMP in a nitrogen atmosphere.

(29) The mixture was 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 was maintained at 190 C.

(30) The water that was formed in the reaction was continuously removed by distillation. The solvent level inside the reactor was maintained at a constant level by addition of further NMP.

(31) After a reaction time of six hours, the reaction was stopped by addition of 1947 ml of NMP with a temperature of 23 C. Nitrogen was bubbled through the mixture for one hour with a rate of 20 l/h and the mixture was let to cool to room temperature. The potassium chloride formed in the reaction was removed by filtration.

Example 5 (According to the Invention): PESU-PEO-Copolymer

(32) In a 4 liter glass reactor fitted with a thermometer, a gas inlet tube and a Dean-Stark-trap, 574.16 g of DCDPS, 492.83 g of DHDPS, 93 g of -C.sub.16/C.sub.18-alkyl,-hydroxy-polyethyleneglykol with a molar ratio of C.sub.16/C.sub.18 rests of 55:45 and with a number average molecular mass Mn of 3100 g/mol and 290.24 g of potassium carbonate with a volume average particle size of 32.4 m were suspended in 1053 ml NMP in a nitrogen atmosphere.

(33) The mixture was 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 was maintained at 190 C.

(34) The water that was formed in the reaction was continuously removed by distillation. The solvent level inside the reactor was maintained at a constant level by addition of further NMP.

(35) After a reaction time of six hours, the reaction was stopped by addition of 1947 ml of NMP with a temperature of 23 C. Nitrogen was bubbled through the mixture for one hour with a rate of 20 l/h and the mixture was let to cool to room temperature. The potassium chloride formed in the reaction was removed by filtration.

Example 6 (According to the Invention): PESU-PEO-Copolymer

(36) In a 4 liter glass reactor fitted with a thermometer, a gas inlet tube and a Dean-Stark-trap, 574.16 g of DCDPS, 485.33 g of DHDPS, 186 g of -C.sub.16/C.sub.18-alkyl,-hydroxy-polyethyleneglykol with a molar ratio of 016/018 rests of 55:45 and with a number average molecular mass Mn of 3100 g/mol and 290.24 g of potassium carbonate with a volume average particle size of 32.4 m were suspended in 1053 ml NMP in a nitrogen atmosphere.

(37) The mixture was 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 was maintained at 190 C.

(38) The water that was formed in the reaction was continuously removed by distillation. The solvent level inside the reactor was maintained at a constant level by addition of further NMP.

(39) After a reaction time of six hours, the reaction was stopped by addition of 1947 ml of NMP with a temperature of 23 C. Nitrogen was bubbled through the mixture for one hour with a rate of 20 l/h and the mixture was let to cool to room temperature. The potassium chloride formed in the reaction was removed by filtration.

Comparative Example 7: PESU-PEO-Copolymer

(40) In a 4 liter glass reactor fitted with a thermometer, a gas inlet tube and a Dean-Stark-trap, 574.16 g of DCDPS, 475.32 g of DHDPS, 205 g of polyethylene glykol with a number average molecular mass Mn of 2050 g/mol and 290.24 g of potassium carbonate with a volume average particle size of 32.4 m were suspended in 1053 ml NMP in a nitrogen atmosphere.

(41) The mixture was 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 was maintained at 190 C.

(42) The water that was formed in the reaction was continuously removed by distillation. The solvent level inside the reactor was maintained at a constant level by addition of further NMP.

(43) After a reaction time of six hours, the reaction was stopped by addition of 1947 ml of NMP with a temperature of 23 C. Nitrogen was bubbled through the mixture for one hour with a rate of 20 l/h and the mixture was let to cool to room temperature. The potassium chloride formed in the reaction was removed by filtration.

(44) TABLE-US-00001 TABLE 1 Analytical data of copolymers prepared in experiments 1 to 7 1 2 3 4 5 6 7 viscosity number 62.1 57.4 56.4 57.9 78 64.7 75.4 [ml/g] polyalkylene oxide 8.0 9.7 18.9 19.1 8.5 15.7 18.2 content (% by weight) Mw/Mn 2.9 3.2 3.4 3.4 3.2 3.2 2.9 Tg [ C.] 174 165 120 119 194 156 122

(45) Copolymers according to the invention showed higher glass transition temperatures than those known from the art.

Preparation of Membranes

Example M1: Preparation of PESU Flat Sheet Membranes (Reference Membrane M1

(46) Into a three neck flask equipped with a magnetic stirrer 80 ml of N-methylpyrrolidone (NMP), 5 g of polyvinylpyrrolidone (PVP, Luvitec K40) and 15 g of polyethersulfone (PESU, Ultrason E 6020P) were added. The mixture was heated under gentle stirring at 60 C. until a homogeneous clear viscous solution was obtained. The solution was degassed overnight at room temperature.

(47) After that the membrane solution was 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 operating at a speed of 5 mm/min. The membrane film was allowed to rest for 30 seconds before immersion in a water bath at 25 C. for 10 minutes.

(48) After the membrane has detached from the glass plate, the membrane was carefully transferred into a water bath for 12 h. Afterwards the membrane was transferred into a bath containing 2000 ppm NaOCl at 50 C. for 4.5 h to remove PVP. After that process the membrane was washed with water at 60 C. and then one time with a 0.5 wt.-% solution of NaBisulfite to remove active chlorine. After several washing steps with water the membrane was stored wet until characterization started.

(49) A flat sheet continuous film with micro structural characteristics of UF membranes having dimension of at least 1015 cm size was obtained. The membrane comprised a top thin skin layer (1-3 microns) and a porous layer underneath (thickness: 100-150 microns).

Example M2: Flat Sheet Membranes Based on Copolymers

(50) Into a three neck flask equipped with a magnetic stirrer 80 ml of N-methylpyrrolidone (NMP), 5 g of polyvinylpyrrolidone (PVP, Luvitec K40) and 15 g of the block copolymer obtained in example 5 were added. The mixture was heated under gentle stirring at 60 C. until a homogeneous clear viscous solution was obtained. The solution was degassed overnight at room temperature.

(51) After that the membrane solution was 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 operating at a speed of 5 mm/min. The membrane film was allowed to rest for 30 seconds before immersion in a water bath at 25 C. for 10 minutes.

(52) After the membrane has detached from the glass plate, the membrane was carefully transferred into a water bath for 12 h. Afterwards the membrane was transferred into a bath containing 2000 ppm NaOCl at 50 C. for 4.5 h to remove PVP. After that process the membrane was washed with water at 60 C. and then one time with a 0.5 wt.-% solution of NaBisulfite to remove active chlorine. After several washing steps with water the membrane was stored wet until characterization started.

(53) A flat sheet continuous film with micro structural characteristics of UF membranes having dimension of at least 1015 cm size was obtained. The membrane comprised a top thin skin layer (1-3 microns) and a porous layer underneath (thickness: 100-150 microns).

Example M3: Flat Sheet Membranes Based on Copolymers

(54) Into a three neck flask equipped with a magnetic stirrer 80 ml of N-methylpyrrolidone (NMP), 5 g of polyvinylpyrrolidone (PVP, Luvitec K40) and 15 g of the block copolymer obtained in example 6 were added. The mixture was heated under gentle stirring at 60 C. until a homogeneous clear viscous solution was obtained. The solution was degassed overnight at room temperature.

(55) After that the membrane solution was 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 operating at a speed of 5 mm/min. The membrane film was allowed to rest for 30 seconds before immersion in a water bath at 25 C. for 10 minutes.

(56) After the membrane has detached from the glass plate, the membrane was carefully transferred into a water bath for 12 h. Afterwards the membrane was transferred into a bath containing 2000 ppm NaOCl at 50 C. for 4.5 h to remove PVP. After that process the membrane was washed with water at 60 C. and then one time with a 0.5 wt.-% solution of NaBisulfite to remove active chlorine. After several washing steps with water the membrane was stored wet until characterization started.

(57) A flat sheet continuous film with micro structural characteristics of UF membranes having dimension of at least 1015 cm size was obtained. The membrane comprised a top thin skin layer (1-3 microns) and a porous layer underneath (thickness: 100-150 microns).

(58) Membrane Characterization:

(59) Using a pressure cell with a diameter of 60 mm, the pure water permeation of the membranes was tested using ultrapure water (salt-free water, additionally filtered by a Millipore UF-system). In a subsequent test, a solution of different PEG-Standards was filtered at a pressure of 0.15 bar. By GPC-measurement of the feed and the permeate, the molecular weight cut-off was determined. The data obtained is summarized in table 2.

(60) TABLE-US-00002 TABLE 2 Characterization of membranes obtained in examples M1 to M3 Sample M1 (reference) M2 M3 PWP [l/m2*h*bar] 460 720 850 MWCO [kg/mol] 90 89 92

(61) The membranes comprising block copolymers according to the invention show higher water permeability at a comparable or slightly improved separation performance than the reference membrane.