U.S. patent application number 09/785193 was filed with the patent office on 2001-09-13 for block copolymers with sulfonated polyether sulfone units.
Invention is credited to Hocker, Hartwig, Keul, Helmut, Weisse, Hilmar.
Application Number | 20010021764 09/785193 |
Document ID | / |
Family ID | 7631325 |
Filed Date | 2001-09-13 |
United States Patent
Application |
20010021764 |
Kind Code |
A1 |
Weisse, Hilmar ; et
al. |
September 13, 2001 |
Block copolymers with sulfonated polyether sulfone units
Abstract
Block copolymers containing blocks of unsulfonated aromatic
polyether sulfones and blocks of aromatic polyether sulfones
sulfonated on the aromatics are characterized in that the block
length of the unsulfonated aromatic polyether sulfones in each case
comprises at least 10 repeating units and that the sequence of the
main chain at the block transitions between two adjacent blocks of
aromatic polyether sulfones is the same as it is inside these
blocks. These block copolymers may be prepared by polycondensation,
and are preferably used as membranes. The block copolymers provide
compounds which in addition to an adjustable degree of sulfonation
have a defined length of sulfonated and unsulfonated blocks. As a
result, the spectrum of the polymers suitable for the preparation
of synthetic membranes can be expanded and graded.
Inventors: |
Weisse, Hilmar; (Mechernich,
DE) ; Keul, Helmut; (Aachen, DE) ; Hocker,
Hartwig; (Aachen, DE) |
Correspondence
Address: |
OLIFF & BERRIDGE, PLC
277 S. WASHINGTON STREET, SUITE 500
ALEXANDRIA
VA
22314
US
|
Family ID: |
7631325 |
Appl. No.: |
09/785193 |
Filed: |
February 20, 2001 |
Current U.S.
Class: |
528/171 ;
528/174; 528/391 |
Current CPC
Class: |
C08G 75/23 20130101;
B01D 71/80 20130101; B01D 71/82 20130101; B01D 71/68 20130101 |
Class at
Publication: |
528/171 ;
528/174; 528/391 |
International
Class: |
C08G 075/23; C08G
065/34; C08G 065/38; C08G 065/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 17, 2000 |
DE |
100 07 272.0 |
Claims
What is claimed is:
1. Block copolymers containing blocks of unsulfonated aromatic
polyether sulfones and blocks of aromatic polyether sulfones
sulfonated on the aromatics, wherein the unsulfonated aromatic
polyether sulfones in each case have a block length comprising at
least 10 repeating units and wherein a sequence of a main chain at
block transitions between two adjacent blocks of aromatic polyether
sulfones is the same as it is inside the blocks of aromatic
polyether sulfones.
2. Block copolymers according to claim 1, wherein the block length
of the unsulfonated aromatic polyether sulfones in each case is in
the range of 30 to 100 repeating units.
3. Block copolymers according to claim 1, wherein the block length
of the unsulfonated aromatic polyether sulfones in each case is in
the range of 50 to 100 repeating units.
4. Block copolymers according to claim 1, wherein the sequence of
the main chain consists of --O--Ph--SO.sub.2--Ph-- repeating
units.
5. A process for preparing block copolymers containing blocks of
unsulfonated aromatic polyether sulfones and blocks of aromatic
polyether sulfones sulfonated on the aromatics, wherein the block
copolymers are prepared by polycondensing divalent, hydroxylated or
halogenated or both, ether and sulfone groups-containing aromatic
compounds as coreactants, one of which coreactants additionally is
sulfonated on the aromatic ring or aromatic rings.
6. A process according to claim 5, wherein the polycondensing of
the coreactants is a nucleophilic aromatic substitution.
7. A process according to claim 5, wherein one of the coreactants
used is a hydroxytelechelic polyether sulfone or a
hydroxytelechelic polyether sulfone sulfonated on the aromatic ring
or rings.
8. A process according to claim 5, wherein one of the coreactants
is a halogentelechelic polyether sulfone or a halogentelechelic
polyether sulfone sulfonated on the aromatic ring or rings.
9. A process according to claim 5, wherein the coreactants
sulfonated on the aromatic ring or rings are first prepared by
reacting the corresponding unsulfonated, hydroxylated or
halogenated or both, ether and sulfone groups-containing aromatic
compounds with the aid of a solution of sulfur trioxide in
concentrated sulfuric acid.
10. A process according to claim 7, wherein the hydroxytelechelic
polyether sulfone coreactant sulfonated on the aromatic ring or
rings is synthesized from a compound of the following structure:
2wherein X and Y may be the same or different and represent the
same or different hydroxyl groups, Z, Z' may be the same or
different and represent hydrogen or alkali metal.
11. A process according to claim 10, wherein the alkali metal is
sodium or potassium.
12. A process according to claim 8, wherein the halogentelechelic
polyether sulfone coreactant sulfonated on the aromatic ring or
rings is synthesized from a compound of the following structure:
3wherein X and Y may be the same or different and represent the
same or different halogen groups, Z, Z' may be the same or
different and represent hydrogen or alkali metal.
13. A process according to claim 12, wherein the halogen groups are
selected from the group consisting of fluorine, chlorine and
bromine.
14. A process according to claim 12, wherein the alkali metal is
sodium or potassium.
15. A process according to claim 12, wherein the halogentelechelic
polyether sulfone coreactant sulfonated on the aromatic ring or
rings is synthesized from 3,3'-sulfonyl bis(6-fluorobenzene
sulfonic acid) or the corresponding disodium salt.
16. A process according to claim 5, wherein the polycondensing is
carried out such that in the block copolymer, a block length of the
unsulfonated aromatic polyether sulfones in each case comprises at
least 10 repeating units.
17. A synthetic membrane containing the block copolymer according
to claim 1.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The invention pertains to block copolymers containing blocks
of unsulfonated aromatic polyether sulfones and blocks of aromatic
polyether sulfones sulfonated on the aromatics, as well as a
process for the preparation thereof. In addition, the present
invention pertains to membranes containing such block
copolymers.
[0003] 2. Discussion of Related Art
[0004] The use of synthetic polymers for membranes and separation
processes based thereon has been known for a long time. In addition
to typical fields of application, such as sea water desalination by
means of reverse osmosis or the ultrafiltration of process waters
from electric immersion painting for recovery of the lacquer,
membrane processes in the fields of food technology, medicine, and
pharmacy are becoming increasingly important. In the last-mentioned
cases, membrane separation processes have the major advantage that
the substances to be separated are not subjected to thermal load or
indeed damaged at all.
[0005] In addition to the always necessary mechanical and thermal
properties, polymers which are suitable for use as constituents and
component parts for medical applications must also possess
properties which are characteristic of medicine, such as
[0006] sterilizability in autoclaves
[0007] very good resistance, even to strong disinfectants
[0008] biocompatibility in contact with skin, tissue or blood.
[0009] Sterilizability is of essential importance when it comes to
use as a membrane. Not least for safety reasons and on ecological
grounds in that case steam sterilization is to be preferred over
chemical sterilization through radiation, especially through gamma
radiation.
[0010] Ordinarily, the steam sterilization takes place by means of
the approximately 30-minute treatment of the membrane with
superheated steam of >110.degree. C. The criterion of steam
sterilizability thus strongly reduces the number of potential
polymers for membranes. For instance, membranes of
polyacrylonitrile cannot be steam sterilized on principle, because
exceeding the glass temperature of the polymer leads to the
material or the membrane being irreversibly damaged. Polymers
susceptible to hydrolysis, e.g., some polycarbonates and
polyamides, likewise do not survive a superheated steam
sterilization without being damaged.
[0011] Steam sterilizable membranes of, e.g., polyether imides,
polyether sulfones or polyvinylidene fluoride are well-known.
[0012] Polyether sulfones fulfill the mechanical and thermal
properties requirements and stand out as a result of an excellent
resistance to chemicals.
[0013] A major drawback to membranes based on, e.g., polyether
sulfone is the hydrophobicity of the membrane material, which
excludes spontaneous wetting with aqueous media. Because of this it
has to be prevented that the membrane dries out completely, or the
membrane has to be treated with a hydrophilizing agent, such as
glycerol, prior to being dried.
[0014] Hydrophilic membranes are remarkable for being wettable with
water. A measure of wettability is the contact angle of a drop of
water vis-a-vis the membrane surface. In the case of hydrophilic
materials, this contact angle will always exceed 90 degrees.
Phenomenologically, wetting of a dialysis membrane can also be
inferred from the fact that a drop of water introduced onto the
membrane surface will penetrate into the membrane after a short
time.
[0015] A further substantial drawback to hydrophobic materials for
use in membranes consists in that they often have a strong,
nonspecific adsorption capacity. Hence when hydrophobic membranes
are used, often a rapid, tightly adhering coverage of the membrane
surface with preferably high-molecular weight solvent constituents
takes place. This phenomenon known as fouling leads to a rapid
deterioration of the membrane permeability. A subsequent treatment
of the membrane with a hydrophilizing agent will not permanently
prevent the fouling.
[0016] Proposals have been made for the use as membrane material of
hydrophilic polymers/polymer systems said not to have the
aforementioned drawbacks. Thus in German published application
DE-OS 3 149 976, it is proposed that for the preparation of a
hydrophilic membrane, use be made of a polymerizate mixture which
in addition to polysulfone or polyamide contains at least 15 wt. %
of polyvinyl pyrrolidone. For the hydrophilizing of, e.g.,
polyimide and polyether sulfone membranes, EP-A-0 228 072 claims
the use of polyethylene glycol in amounts of 44 to 70 wt. %,
calculated on the polymer solution.
[0017] The hydrophilizing of membranes by using large amounts of
water-soluble polymers has the drawback, however, that the
hydrophilicity of the membrane steadily declines when it is used in
aqueous media, since the water-soluble polymer is washed out. This
can lead to the membrane material regaining its original
hydrophobicity and exhibiting the aforementioned negative secondary
phenomena associated therewith.
[0018] The drawbacks can be avoided by the use of hydrophilic, yet
water-insoluble polymers for the preparation of membranes. Thus in
a series of patents, e.g., EP-A-0 182 506 and U.S. Pat. No.
3,855,122, the preparation of membranes from sulfonated polymers is
claimed. However, the processes described there are suitable only
for the preparation of flat membranes. The membranes have a high
salt retention capacity and are primarily eligible for use in
reverse osmosis.
[0019] DE-OS 3 149 976 proposes the preparation of aromatic
polyether sulfones by sulfonation with the aid of a solution of
sulfur trioxide in sulfuric acid, with the content of sulfur
trioxide, calculated on the total amount of pure sulfuric acid
present in the reaction mixture, being kept at a value of less than
6 wt. % during the entire period of sulfonation.
[0020] In this way the degree of sulfonation, i.e., the quotient of
the total number of sulfonic acid groups in the polymer and the
total number of repeating monomer units, should be easily
controllable; however, it is not possible to set other than a
random distribution of the sulfonic acid groups in the polymer.
[0021] However, for regulation of the biocompatibility, it is
desirable when not only the total number of sulfonic acid groups in
the polymer, but also their distribution in the polymer chain can
be influenced. By the selective introduction of, e.g., domains with
high and low degrees of sulfonation, the variational possibilities
with respect to the functional polymer groups can be increased and
thus, e.g., the hydrophilicity properties can be graded even more
selectively.
[0022] Such block copolymers containing blocks of sulfonated and
unsulfonated polyether sulfones are known, e.g., from JP 1009230.
In this document, a block copolymer of polyether sulfone and
sulfonated polyether sulfone is described which is prepared using
.alpha.,.alpha.'-dichloro-p-- xylene as coupling reagent and where
the block transitions are made up of aliphatic groups, which may
lead to inhomogeneities and, at worst, to weak points in the chain.
Moreover, aliphatic groups may enter into unfavourable interactions
with blood and for that reason their presence in, e.g.,
haemodialysis membranes is highly undesired.
[0023] Finally, EP-A-112724 describes a process for sulfonating
polysulfones containing repeating units of the formula
--Ph--SO.sub.2--Ph--O--, wherein the polysulfone is first of all
suspended in a liquid halogenated hydrocarbon and then sulfonated
with a sulfonating reagent, such as sulfur trioxide. According to
EP-A-112724, the sulfonated product can resemble to a certain
degree that of a block copolymer with alternating regions of highly
sulfonated and unsulfonated chain sequences. The document does not
pronounce on the length of the sulfonated and unsulfonated
sequences, respectively. Moreover, EP-A-112724 does not disclose
either whether and in which way these sequence lengths can be
controlled. The document even leaves open whether in the described
process it is actually block copolymers which are formed, since
there is talk only of a resemblance to or the appearance of the
existence of block copolymers. EP-A-112724 is consistently directed
to the sulfonation of polysulfones, and not to a process for the
preparation of block copolymers.
SUMMARY OF THE INVENTION
[0024] The invention has for its object to provide block copolymers
containing blocks of unsulfonated aromatic polyether sulfones and
blocks of aromatic polyether sulfones sulfonated on the aromatics,
as well as a process for the preparation thereof, with the
drawbacks of the prior art at least being reduced.
[0025] This object is achieved by means of block copolymers
containing blocks of unsulfonated aromatic polyether sulfones and
blocks of aromatic polyether sulfones sulfonated on the aromatics
which are characterized in that the length of the blocks of
unsulfonated aromatic polyether sulfones in each case comprises at
least 10 repeating units, and in that the sequence of the main
chain at the block transitions between two adjacent blocks of
aromatic polyether sulfones is the same as that inside these
blocks.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0026] Although there is no upper limit for the block length of the
unsulfonated aromatic repeating units on principle, block
copolymers with an upper limit of about 100 unsulfonated repeating
units are preferred.
[0027] In the case of the block copolymers according to the
invention, a block length of the unsulfonated aromatic polyether
sulfones of always between 30 and 100, more preferably between 50
and 100, repeating units is especially preferred.
[0028] Aromatic polyether sulfones in this case means in the first
place polymers where the sequence of the main chain has a sulfone
group between two aromatic groups and an ether bond between two
aromatic groups, where the two aromatic groups between which the
sulfone group is present are each connected to a further aromatic
group by means of an ether bond. By sequence of the main chain is
thus meant in this case the sequence of the atoms forming the
polymer chain and their bonds to one another. In the case of
branched polymers, the main chain is the longest unbranched chain.
Typical sequences for polyether sulfones can be described, e.g., by
the n-fold succession of monomeric repeating units, such as
--[--O--Ph--SO.sub.2--Ph--]--. In this case Ph stands for the
aromatic group and n for the number of repeating units in the
polymer.
[0029] The term aromatic polyether sulfone (PES), however, also
pertains to polymers of which the main chain sequence first of all
has two or more successive aromatic groups connected by ether
groups before the next sulfone group follows between two aromatic
groups, as is for instance the case in a polyether ether sulfone
(PEES). Such sequences can for instance be described by the n-fold
succession of monomeric repeating units, such as
--[--O--Ph--O--Ph--SO.sub.2--Ph--]--. Alternatively, of course, it
is also possible to have first of all two or more aromatic groups
connected by sulfone groups following one another, before the next
ether group follows between two aromatic groups.
[0030] The cross-linking of the aromatic groups with the
corresponding substituents can in each case take place in the
ortho-, meta-, or para-position. Optionally, the aromatic groups
will carry further substituents.
[0031] Preferred within the framework of the present invention are
those block copolymers where the cross-linkings take place in the
para-position.
[0032] The term "sulfonated" is taken to mean above all the
presence of sulfonic acid groups on the aromatic rings, in which
case technically a hydrogen atom connected to the aromatic ring of
the ether sulfone unit is replaced by a sulfonic acid group. For
many application purposes the sulfonated polymer is less suitable
in the form of free sulfonic acid groups than in the form of their
salts, e.g., metal salts or ammonium salts. The conversion to these
salts can take place through neutralization with the corresponding
bases in a solvent. For that reason the term "sulfonated" also
encompasses these salts.
[0033] For the rest, sulfonated and unsulfonated polyether sulfones
or polyether ether sulfones are well-known to the skilled person
and need no further elucidation here.
[0034] The block copolymers according to the invention provide
compounds which in addition to an adjustable degree of sulfonation
also have a defined length of sulfonated and unsulfonated blocks.
As a result, the spectrum of the polymers suitable for the
preparation of synthetic membranes can be expanded and graded, for
instance for a selective setting of the hydrophilicity and the
biocompatibility. Block copolymers with blocks of sulfonated and
unsulfonated polyether sulfones which have these properties are
neither disclosed in the known prior art nor suggested therein.
[0035] In the case of particularly suitable block copolymers, the
sequence of the total main chain consists of
--O--Ph--SO.sub.2--Ph-- repeating units. Of course, in that case
there will be aromatics having sulfonic acid groups in the blocks
of sulfonated aromatic polyether sulfones.
[0036] In the case of the block copolymers according to the
invention, this sulfonation on the aromatic groups can only be
found in certain domains of the block copolymer, viz. in the blocks
of sulfonated polyether sulfones. The sequence of the main chain is
not altered by this.
[0037] The degree of sulfonation of the block copolymers is defined
as the quotient of the total number of sulfonic acid groups in the
polymer and the total number of repeating monomer units. A degree
of sulfonation of, say, 0.2 thus means that on average there will
be a sulfonic acid group present on every fifth monomer unit,
which, e.g., in the case of the block copolymers according to the
invention is realized by a block with 80 unsulfonated monomer
units, followed by a block with 20 sulfonated monomer units. The
degree of sulfonation is decisive for the hydrophilicity and the
ion exchange capacity, respectively, of the sulfonated polymer. It
can be determined, e.g., by titration of the sulfonic acid groups
on the one hand and determination of the monomer units on the
other. According to the present invention, however, use is made of
spectroscopic methods, which are also suitable when the sulfonic
acid groups are present in the form of their salts. In the first
place, the determination can be carried out with the aid of a
.sup.1H-NMR method, as decribed in the literature (J. Membrane Sci.
83 (1993) 21). In addition to this, also .sup.13C-NMR-spectroscopy
is suitable for determining the degree of sulfonation. Such
quantitative information can be derived from comparing the spectra
of, e.g., polyether sulfone and sulfonated polyether sulfone. The
skilled person will then be capable of determining the degree of
sulfonation via the ratio of intensity of certain carbon
signals.
[0038] The mentioned ion exchange capacity (IEC), which represents
a measure of the hydrophilicity, can be indicated in meq/g. 1 meq/g
means that per gram of polymer, 1 mmole of protons can be exchanged
for 1/n mmole of an n-valent cation. The IEC can again be
determined by titration.
[0039] The block copolymers according to the invention can have the
same or a different degree of sulfonation in the blocks of aromatic
sulfonated polyether sulfones.
[0040] Thus, e.g., a degree of sulfonation of 0.2 could be produced
in a block copolymer in the first place--as already described
above--by means of an alternating series of in each case 80
unsulfonated monomer units (degree of sulfonation in the block=0)
and 20 sulfonated monomer units (degree of sulfonation in the
block=1); however, a block copolymer with the same degree of
sulfonation could also be produced through the alternating sequence
of 60 unsulfonated monomer units (degree of sulfonation in the
block=0), 15 sulfonated monomer units (degree of sulfonation in the
block=1) and 25 sulfonated monomer units (degree of sulfonation in
the block=0.2).
[0041] The invention is further directed to a process for the
preparation of block copolymers containing blocks of unsulfonated
aromatic polyether sulfones and blocks of aromatic polyether
sulfones sulfonated on the aromatics, which is characterized in
that the block copolymers are prepared by the polycondensation of
divalent, hydroxylated and/or halogenated, ether and sulfone
groups-containing aromatic compounds as coreactants, one of which
coreactants additionally is sulfonated on the aromatic ring or the
aromatic rings.
[0042] By the term "divalent" is meant that the coreactants always
provide two functionalities for a condensation reaction. These
functionalities are either halogen or hydroxyl groups, which in
each case are present as substituents on the aromatic rings or the
aromatic ring of the coreactants. The coreactants may contain only
the functional groups of one type, i.e., only hydroxyl groups or
only halogen groups, as substituents, but of course also both types
of functional groups may be present on the same coreactant. In the
former case, e.g., aromatic dihalogen compounds will react with
aromatic dihydroxyl compounds, in which case two coreactants with
different terminal groups are required for the forming of the
aromatic polyether sulfones, while in the latter it may be a case
of for instance halogenated hydroxyl compounds and as a result of
this the coreactants will always have the same terminal groups. Of
course also mixtures of different types may be employed, i.e., for
instance dihalogen compounds with dihydroxyl compounds and
halogenated hydroxyl compounds as coreactants.
[0043] The term "coreactant" comprises monomers but is not limited
thereto. Needless to say, oligomers or polymers with the
corresponding functionalities, i.e., terminal groups, may also be
used.
[0044] The number of coreactants reacting with one another is not
subject to any restrictions on principle.
[0045] In the process according to the invention, it is preferred
that the poly-condensation of the coreactant is a nucleophilic
aromatic substitution. As a result of this, the sequence of the
main chain can be maintained and continued at the block transitions
in a very simple manner.
[0046] It is preferred for the process according to the invention
when one of the coreactants used is a hydroxytelechelic polyether
sulfone or a hydroxytelechelic polyether sulfone sulfonated on the
aromatics.
[0047] The term "telechelic" is known to the skilled person. As a
rule, it concerns oligomers or low-molecular weight polymers
carrying monofunctional terminal groups on both chain ends.
According to the present invention, this designation is also used
for polymeric and oligomeric substances with defined reactive
terminal groups. Thus for instance, the designation
hydroxytelechelic polyether sulfone is used for polyether and
oligoether sulfones which have hydroxyl groups present on both
chain ends.
[0048] Hydroxytelechelic polyether sulfones are known. They can be
obtained, e.g., by reacting bis(4-hydroxyphenyl)sulfone with
bis(4-chlorophenyl)sulfone in a molar ratio of q=0.92 to 0.98
(hydroxyl constituents in excess) in 1,1-dioxothiolane in the
presence of potassium carbonate at 200.degree. C.
[0049] Hydroxytelechelic, sulfonated polyether sulfones can be
obtained by an analogous reaction of the hydroxytelechelic
polyether sulfones with oleum. Such a synthesis is disclosed for
instance in DE-OS 38 14 759 in the example of the conversion of
polyether sulfones into sulfonated polyether sulfones. In that
process, the educt is first dissolved in concentrated sulfuric
acid, so that an approx. 10 wt. % solution is formed. At about
10.degree. C., the amount of 65%-oleum which is required for the
degree of sulfonation aimed for is added. The reaction solution is
after-stirred for about 1-2 hours and the product is then obtained
by precipitation in water.
[0050] The hydroxytelechelic compounds can be characterized by
means of conventional methods well-known to the skilled person,
with .sup.1H-NMR and .sup.13C-NMR spectroscopy being particularly
suitable. In this connection, .sup.1H-NMR spectroscopy for instance
is not only suitable for making statements about the terminal
groups, but it is also possible, through the exchange of suitable
signals, to obtain details about the molecular weight of the
obtained polymeric or oligomeric compounds.
[0051] For the process according to the invention, it is further
preferred when one of the coreactants used is a halogentelechelic
polyether sulfone or a halogentelechelic polyether sulfone
sulfonated on the aromatics.
[0052] Halogentelechelic polyether sulfones are made available,
e.g., by the reaction of hydroxytelechelic polyether sulfones with
an excess of bis(4-halogen-phenyl)sulfone. Preferred halogens are
fluorine and chlorine. Thus, the synthesis of the especially
preferred fluorotelechelic polyether sulfone proceeds by reacting
hydroxytelechelic polyether sulfone with bis(4-fluorphenyl)sulfone,
which is used in fourfold molar excess, in 1,1-dioxothiolane at
200.degree. C., followed by precipitation of the reaction solution
in water/ethanol (1:1, v/v).
[0053] It is advantageous for the process according to the
invention when the coreactants sulfonated on the aromatics are
first prepared by reacting the corresponding unsulfonated,
hydroxylated and/or halogenated ether and sulfone
groups-containing, aromatic compounds with the aid of a solution of
sulfur trioxide in concentrated sulfuric acid.
[0054] This can be done, as was described above on the occasion of
the synthesis of the hydroxytelechelic, sulfonated compounds, by
means of an analogous conversion using SO.sub.3. However, it is
also possible that already the monomers are sulfonated in oleum. In
this way the halogentelechelic, sulfonated polyether sulfones can
be obtained by reacting 3,3'-sulfonyl bis(6-halogenbenzene sulfonic
acid) dialkali salt with bis(4-hydroxyphenyl)sulfone in
1,1-dioxothiolane in a molar ratio of the educts q of about 0.85
(halogen constituents in excess). The sulfonated dihalogen
compounds are obtained from the corresponding
bis(4-halogenphenyl)sulfones. In this way the 3,3'-sulfonyl
bis(6-fluorobenzene sulfonic acid) disodium salt can be prepared by
the sulfonation of bis(4-fluorophenyl)sulfone in oleum, followed by
salting out with common salt.
[0055] Likewise for instance also the monomeric sulfonated
dihydroxyl compounds can be obtained, by
bis(4-hydroxyphenyl)sulfone being sulfonated in 96%-sulfuric
acid.
[0056] Of course, starting from the previously sulfonated monomeric
dihalogen compounds, such as the bis(4-halogenphenyl)sulfones, it
is also possible to obtain the hydroxytelechelic sulfonated
polyether sulfones. This can easily be done, e.g., by using the
corresponding molar excess of bis(4-hydroxyphenyl)sulfone in
1,1-dioxothiolane. The skilled person is capable of determining the
corresponding mixing ratios on the basis of his professional
knowledge and/or simple routine tests, without a creative act.
[0057] Hence it is preferred in the process according to the
invention, that for the synthesis of the telechelic coreactants
sulfonated on the aromatics use is made of a compound of the
following structure: 1
[0058] wherein
[0059] X and Y may be the same or different and represent the same
or different halogen groups, such as fluorine, chlorine, bromine
and/or hydroxyl groups;
[0060] Z, Z' may be the same or different and represent hydrogen or
alkali metal, such as sodium or potassium.
[0061] Covered by this structure are compounds such as
3,3'-sulfonyl(6-fluorobenzene sulfonic acid-6-chlorobenzene
sulfonic acid) as well as the disodium salt thereof
3,3'-sulfonylbis(6-chlorobenze- ne sulfonic acid) as well as the
dipotassium salt thereof, 3,3'-sulfonylbis(6-hydroxybenzene
sulfonic acid) as well as the disodium salt thereof.
[0062] Quite especially preferably for the synthesis of the
telechelic coreactants sulfonated on the aromatics, use is made of
3,3'-sulfonylbis(6-fluorobenzene sulfonic acid) or the
corresponding disodium salt thereof.
[0063] It proves to be especially advantageous in the process
according to the invention when the polycondensation is carried out
in such a way that in the block copolymer being formed the block
length of the unsulfonated aromatic polyether sulfones in each case
comprises at least 10 repeating units. An upper limit of about 100
unsulfonated repeating units as a rule is considered sufficient
here. Preferably, the process should be carried out in such a way
that between 30 and 100, more preferably 50 to 100 repeating units
are present in the block copolymer.
[0064] This can be done, e.g., by reacting a halogentelechelic,
sulfonated polyether sulfone with a hydroxytelechelic polyether
sulfone, with care having to be taken that the hydroxytelechelic
constituent comprises at least 10 repeating units.
[0065] The skilled person is easily capable, within the framework
of the disclosure of this invention, to select suitable
combinations of coreactants, in order to be able to carry out the
process according to the invention.
[0066] The invention is also directed to synthetic membranes which
contain the block copolymers according to the invention and/or the
products from the process according to the invention.
[0067] The following examples serve to elucidate the present
invention and are not to be interpreted as limiting the invention
in any way.
[0068] Working Technique and Analytics Spectroscopy:
[0069] The spectroscopic characterization of the synthesized
products and intermediate products as a rule was carried out using
NMR spectroscopy (Bruker, Model DPX 300; .sup.1H-NMR spectroscopy,
300 MHz; .sup.13C-NMR spectroscopy, 75 MHz) or IR spectroscopy:
(Nicolet, FTIR Spectrometer Avatar 320 with ATR attachment,
Thunderdome with germanium crystal).
[0070] Gel Permeation Chromatography (GPC):
[0071] (Eluent: dimethyl acetamide distilled over CaH.sub.2 with an
admixture of 1.220 g/1 LiCl; HPLC pump: Bischoff; flow: 0.5 ml/min;
autosampler: Bischoff 728; injection valve: Bischoff, EPS-120 with
rotation high-pressure valve made by Rheodyne with 202.4 .mu.l
injection volume).
[0072] Column combination:
[0073] column temperature 60.degree. C.
[0074] MZ-Gel (8.0 mm.times.50 mm) 100 .ANG., 10 .mu.m
(pre-column)
[0075] PL-Gel (7.5 mm.times.300 mm) 100 .ANG., 5 .mu.m
[0076] MZ-Gel (8.0 mm.times.300 mm) 500 .ANG., 10 .mu.m
[0077] PL-Gel (7.5 mm.times.300 mm) 1,000 .ANG., 5 .mu.m
[0078] PL-Gel (7.5 mm.times.300 mm) 10,000 .ANG., 5 .mu.m
[0079] Differential Refractometer:
[0080] Wyatt Optilab 903, 488 nm, analyzer temperature: 25.degree.
C. The calibration constant was determined with a dilution sequence
of degassed aqueous common salt solution.
[0081] Light Scattering Detector:
[0082] Wyatt Dawn DSP with argon laser, .lambda.=488 nm, set laser
power when carrying out the measurements: 15 mW, fluoresence filter
on detectors 7 to 14, analyzer K5 or F2. The calibration constant
was determined with degassed toluene (for analysis).
[0083] UV Detector:
[0084] Carlo Erba Instruments, micro UVIS 20 Measuring and analysis
software: Wyatt, Astra 4.5
[0085] Solvent and Chemicals:
[0086] All solvents are washed using conventional laboratory
methods. Some polycondensations are carried out under dry nitrogen
as protective gas. To this end, nitrogen of quality 5.0 is dried on
a 0.4 nm molecular sieve and potassium finely distributed on
alumina. In all cases where water is used, the water used is
de-ionized.
[0087] The non-synthesized chemicals are employed as purchased:
int. al.: bis(4-hydroxyphenyl)sulfone (Merck),
bis(4-fluorophenyl)sulfone (Aldrich), bis(4-chlorophenyl)sulfone
(Merck)
[0088] Washing:
[0089] For washing water-soluble polymers there are used as
dialysis membranes:
[0090] cuprophane flexible membrane type 20 145, Code No.
86274-200001 (Akzo Nobel), exclusion limit for proteins: 1000
Dalton.
[0091] Quantitative .sup.13C-NMR Measurements
[0092] To obtain routine .sup.13C-NMR spectra, the 1H nuclei are
decoupled by a permanent decoupling irradiation. The thus effected
saturation of the 1H resonances leads to a reinforcement of the
.sup.13C signals as a result of the Nuclear Overhauser Effect (NOE)
up to 2.9-fold, which is fully wanted in standard measurements. For
quantitative .sup.13C-NMR measurements this effect is unfavourable,
since different .sup.13C nuclei are reinforced differently and thus
the relative intensities are not only determined by the frequencies
of the nuclei in question, but also by differing strong NOEs. In
the Inverse-Gated-Decoupling pulse sequence (cf. J. K. M. Sanders,
B. K. Hunter, Modern NMR-Spectroscopy, Oxford University Press,
1988) the decoupler for that reason is only turned on when
recording the Free Induction Decay (FID). In this period the
saturation of the .sup.1H resonances is not achieved and no
different reinforcement of the .sup.13C nuclei is effected by the
NOE. Furthermore, after each pulse the system has to be completely
relaxed again. The relaxation time T.sub.eff of .sup.13C nuclei in
polymers is up to 0.3 s. The pause between the pulses should be at
least 5T.sub.eff. For security, however, a pause of 10 s is
maintained between each pulse. The small gyromagnetic ratio of the
.sup.13C nucleus, its low frequency, and the prevention of NOE lead
to a comparatively low sensitivity of the measurement. In order to
still arrive at an acceptable signal-noise ratio (SN) of at least
50, the number of pulses (NS) should be correspondingly high, as in
the case of FT-NMR spectrometers SN.varies.(NS).sup.1/2 holds.
Frequently 5,000 pulses were recorded in the quantitative
.sup.13C-NMR measurements, which resulted in measuring times of
about 14 hours. By multiplying the measured FID by an exponential
function with a line broadening factor of 3, the SN was increased
still further in all analyses carried out. Finally, before the
digital integration of the signals also a base line correction of
the spectra was carried out.
[0093] I. Monomer Syntheses
[0094] a) 3,3'-Sulfonyl Bis(6-hydroxybenzene Sulfonic Acid)
Disodium Salt
[0095] 75.09 g of bis(4-hydroxyphenyl)sulfone were dissolved, with
stirring, in 50 ml 96%-sulfuric acid, heated to 100.degree. C., and
kept at this temperature for 48 hours. After pouring of the
reaction mixture into water and the addition of common salt up to
saturation of the solution, the product precipitates as a white
deposit. It is syphoned off and recrystallized from 370 ml
ethanol/H.sub.2O (4:1). A further fraction is obtained after
concentrating the mother liquor and renewed crystallization. 40.20
g (30% yield) of 3,3'-sulfonyl bis(6-hydroxybenzene sulfonic acid)
disodium salt are obtained in the form of fine white needles. The
melting or decomposition point is above 250.degree. C. The
characterization takes place with .sup.1H-NMR and .sup.13C-NMR
spectroscopy.
[0096] b) 3,3'-sulfonyl Bis(6-fluorobenzene Sulfonic Acid) Disodium
Salt
[0097] 50.45 g of bis(4-fluorophenyl)sulfone were dissolved in 50
ml of oleum in a round-bottomed flask with a drying conduit under
cooling with ice and stirring. After 45 minutes of stirring with
cooling with ice the reaction mixture is kept at 40.degree. C. for
4 hours and then poured out into 1 l of water and cooled. The
product is salted out with common salt, washed with a saturated
aqueous common salt solution, and recrystallized from 710 ml
ethanol/water (11:1). 25.32 g (28% yield) of product are obtained
in the form of clear needles, which by drying under high vacuum at
120.degree. C. crumble to a white, hygroscopic powder, which to
prevent renewed water uptake is stored under nitrogen. The melting
or decomposition point is above 250.degree. C. The characterization
takes place with .sup.1H-NMR and .sup.13C-NMR spectroscopy.
[0098] c) 3,3'-sulfonyl-(6-fluorobenzene Sulfonic
Acid-6'-chlorobenzene Sulfonic Acid) Disodium Salt
[0099] g of 4-[4-(fluorophenyl)sulfonyl]chlorobenzene (synthesis as
described in Chem. Ber. 86 (1953) 172) are dissolved in 10 ml
60%-oleum in a round-bottomed flask with a drying conduit under
cooling with ice and stirring. The solution is allowed to thaw to
10.degree. C. and the cooling bath is kept at 10.degree. C. for
another 3 hours. Into the reaction mixture are charged 30 ml of
water and the product is salted out with common salt. It
precipitates as a white deposit, is syphoned off, washed with a
saturated common salt solution, and recrystallized from 100 ml
ethanol/water 5:1. 3,3'-sulfonyl-(6-fluorobenzene sulfonic
acid-6-chlorobenzene sulfonic acid) disodium salt precipitates as
clear fine needles, which crumble after drying under high vacuum at
150.degree. C. Obtained is 1.69 g of product (48% yield). The
melting or decomposition point is above 250.degree. C. The
characterization takes place with .sup.1H-NMR and .sup.13C-NMR
spectroscopy.
[0100] d) 3,3'-sulfonyl Bis(6-chlorobenzene Sulfonic Acid)
Dipotassium Salt
[0101] 57.44 g of bis(4-chlorophenyl)sulfone are dissolved in
60%-oleum in a round-bottomed flask with a drying conduit under
cooling with ice and stirring, heated to 120.degree. C., and kept
at this temperature overnight. The reaction mixture is added to
water and the product is salted out with potassium chloride. It
precipitates as a white deposit, is syphoned off, washed with a
saturated potassium chloride solution, and recrystallized from
ethanol/water (5:4). 65.4 g (62% yield) are obtained as product in
white needles, which crumble to a white powder by drying under high
vacuum at 120.degree. C. The melting or decomposition point is
above 250.degree. C. The characterization takes place with
.sup.1H-NMR and .sup.13C-NMR spectroscopy.
[0102] II. Polymer Syntheses (Syntheses of the Telechelics)
[0103] a) Hydroxytelechelic Polyether Sulfone
[0104] In a Schlenk flask equipped with a magnetic stirrer and a
reflux condenser 37.541 g of bis(4-hydroxyphenyl)sulfone are
dissolved in 200 ml of 1,1-dioxothiolane at 60.degree. C. To this
solution are added 21.8 g of potassium carbonate and 20 ml of
water. After 30 minutes of stirring at 60.degree. C., the water is
distilled off within one hour with a membrane pump at 15 mbar and
120.degree. C. and subsequently 40.059 g of
bis(4-chlorophenyl)sulfone (q=0.93) is added. The reaction mixture
is heated under vacuum (160 mbar) to 200.degree. C. and kept under
these conditions for 6 hours. The formed light-brown solution is
slowly fed to a mixture of 1 l of water and 1 l of ethanol. The
formed deposit is syphoned off, finely ground with a mortar, and
then extracted for one hour with a boiling mixture of ethanol/water
(1:1 v/v) in order to remove occluded salts. The isolated deposit
is extraced twice more with boiling ethanol for 30 minutes, to
completely remove the remaining 1,1-dioxothiolane. After the
washing process the white, powdery product is first dried in a
vacuum drying cabinet at 10 mbar and 70.degree. C. and then under
high vacuum at 110.degree. C. The product is obtained in a yield of
61.2 g (98% of theory) and has an Mn of about 7,200 (determined by
.sup.1H-NMR). The product is used, int. al., for the preparation of
fluorotelechelic polyether sulfones (see below).
[0105] b) Fluorotelechelic Polyether Sulfone
[0106] In a Schlenk flask equipped with a magnetic stirrer and a
reflux condenser 60 g of the hydroxytelechelic polyether sulfone
obtained as specified in II a) are dissolved in 300 ml of
1,1-dioxothiolane at 60.degree. C. To this solution are added 2.76
g of potassium carbonate and 10 ml of water. After 30 minutes, the
water is distilled off with a membrane pump at 15 mbar and
120.degree. C. and subsequently 15.2 g of
bis-(4-fluorophenyl)sulfone are added. The reaction mixture is
heated under vacuum (160 mbar) to 200.degree. C. and kept under
these conditions for 6 hours. The formed light-brown solution is
poured slowly into water/ethanol (1:1, v/v). The formed deposit is
syphoned off, ground finely with a mortar, and then extracted with
a boiling mixture of water/ethanol (1:1, v/v) for 1 hour, in order
to remove occluded salts. The isolated deposit is extraced twice
more with boiling ethanol for 30 minutes, to completely remove the
remaining 1,1-dioxothiolane and excess bis-(4-fluorophenyl)sulfone.
After the washing process, the white product is dried under high
vacuum at 110.degree. C. Obtained are 61.9 g (95% of theory) with
an Mn of about 4,800 (determined by .sup.1H-NMR).
[0107] c) Hydroxytelechelic, Sulfonated Polyether Sulfone
[0108] In a Schlenk flask equipped with a magnetic stirrer and a
reflux condenser 8.755 g of bis(4-hydroxyphenyl)sulfone are
dissolved in 120 ml of 1,1-dioxothiolane at 60.degree. C. To this
solution are added 5.08 g of potassium carbonate and 30 ml of
water. After 30 minutes of stirring, 240 ml of chlorobenzene are
added. The water and chlorobenzene are distilled off completely
with the aid of a distillation bridge, with the last remaining
chlorobenzene being driven out with dry nitrogen. To the thus
formed white suspension are added at about 100.degree. C. 15.381 g
of 3,3'-sulfonyl bis(6-chlorobenzene sulfonic acid) dipotassium
salt. The reaction mixture is heated to 230.degree. C. under a dry
nitrogen atmosphere and kept at this temperature for 6 hours. The
formed light-brown solution is poured into five times as much
acetone, with the crude product precipitating as a white to
light-brown deposit. The crude product is syphoned off, dissolved
in a little water, and the solution is dialyzed with water as
dialyzate. The dialyzate is concentrated in a rotation evaporator
and freed of water by freeze drying and dried under high vacuum at
150.degree. C. Obtained are 12.77 g (58% of theory) with an Mn of
about 9,100 (determined by GPC light scattering).
[0109] d) Fluorotelechelic, Sulfonated Polyether Sulfone
[0110] In a Schlenk flask equipped with a magnetic stirrer and a
reflux condenser 2.374 g of bis(4-hydroxyphenyl)sulfone are
dissolved in 45 ml of 1,1-dioxothiolane at 60.degree. C. To this
solution are added 1.11 g of sodium carbonate and 3 ml of water.
After 30 minutes of stirring, 30 ml of chlorobenzene are added. The
water and chlorobenzene are distilled off completely with the aid
of a distillation bridge, with the last remaining chlorobenzene
being distilled off at 160.degree. C. and 250 mbar. To the thus
formed white suspension are added at about 100.degree. C. 5.116 g
of 3,3'-sulfonyl bis(6-fluorobenzene sulfonic acid) disodium salt.
The reaction mixture is heated to 195.degree. C. under a dry
nitrogen atmosphere and kept at this temperature for 10 hours. The
formed light-brown solution is poured into five times as much
acetone, with the crude product precipitating as a white to
light-brown deposit. The crude product is syphoned off, dissolved
in a little water, and the solution is dialyzed with water as
dialyzate. The dialyzate is concentrated in a rotation evaporator
and freed of water by freeze drying and dried under high vacuum at
150.degree. C. Obtained are 4.58 g (73% of theory) with an Mn of
about 7,800 (determined by .sup.1H-NMR).
[0111] III. Analogous Sulfonation
[0112] a) Synthesis variant 1
[0113] In a double-walled 500 ml three-neck flask equipped with a
KPG stirrer, a dropping funnel, and an internal thermometer, which
is kept at a constant temperature of 10.degree. C. by a cryostat,
the compound to be sulfonated is dissolved in concentrated sulfuric
acid, so that a 10 wt. % solution is formed. When the compound is
completely dissolved in the sulfuric acid, the amount of 65%-oleum
required for the aimed at degree of sulfonation is added dropwise,
with as vigorous stirring as possible, to the solution in such a
way that the internal temperature of 15.degree. C. is not exceeded.
The amount of sulfuric acid and oleum is calculated such that in
the reaction solution, a certain amount of free SO.sub.3 is formed,
which reacts with the compound to be sulfonated and produces an
equimolar amount of sulfonated aromatics in the compound. In the
synthesis, attention has to be paid to the exclusion of moisture.
Furthermore, the oleum has to drop into the reaction solution as
directly as possible, since otherwise SO.sub.3 will crystallize on
the cold glass wall of the reaction vessel. After the dropwise
addition, the reaction solution is after-stirred for one hour at
10.degree. C. After that, the further cooled reaction solution is
poured into 20 to 30 times as much water.
[0114] b) Synthesis Variant 2
[0115] The procedure is as in synthesis variant 1. However, after
the dropwise addition of the oleum the reaction solution is
after-stirred for 12 hours at 30.degree. C. After that it is poured
into 20 to 30 times as much water.
[0116] Processing Variant 1 for Water-soluble Sulfonated Reaction
Products
[0117] The reaction solution diluted with the same amount of water
is dialyzed several times in dialysis membranes with water as
dialyzate, until the mother liquor can no longer be distinguished
from water as regards its pH value. The dialysis residue is
concentrated to about {fraction (1/10)} of its volume on a rotation
evaporator and freed of most of the water by freeze drying. The
last remaining water is removed under high vacuum at 120.degree. C.
The sulfonated reaction products are hygroscopic and hence are
stored under dry nitrogen.
[0118] For the preparation of the corresponding sodium sulfonate an
aqueous solution is prepared, to which sodium hydrogen carbonate is
added until the solution no longer shows an acid reaction. The
product solution is dialyzed three times within 36 hours in
dialysis membranes with the 20 to 30-fold amount of water as
dialyzate. Drying under high vacuum takes place at 150.degree.
C.
[0119] Processing Variant 2 for Water-insoluble Sulfonated Reaction
Products
[0120] If the precipitated sulfonated reaction product is
filamentary, it is extracted cold with water several times, until
the extract can no longer be distinguished from the water used for
the extraction as regards the pH value. If on the other hand the
product is powdery, it is syphoned off with the Buchner funnel and
washed several times with water, until the washing water in terms
of the pH value is no longer distinguishable from its starting
value. The product is pre-dried on a rotation evaporator. The last
remaining water is removed under high vacuum at 120.degree. C.
[0121] For the preparation of the corresponding sodium sulfonate
the product is dissolved in N,N-dimethyl acetamide, about 10 vol %
of water is added, and sodium carbonate is added until the solution
no longer shows an acid reaction. The solution is poured into five
times as much water. When the product is water-soluble, there is
further processing as in processing variant 1. When the product is
not water-soluble, processing takes place as described above for
water-insoluble sulfonated products. Drying under high vacuum
proceeds in any case at 150.degree. C.
EXAMPLE 1
[0122] Block Copolymers of Hydroxytelechelic Sulfonated Polyether
Sulfones and Fluorotelechelic Polyether Sulfones
[0123] In a Schlenk flask equipped with a magnetic stirrer and a
reflux condenser 19.17 g of hydroxytelechelic, sulfonated polyether
sulfone (Mn.apprxeq.14,900, according to .sup.1H-NMR, prepared as
described in III a) of a hydroxytelechelic polyether sulfone with
an Mn of about 5,000) are dissolved in 100 ml of 1,1-dioxothiolane
at 60.degree. C. To this solution, 10 ml of water are added and
potassium carbonate until the solution shows an alkaline reaction.
After 30 minutes of stirring, the solution is heated to 120.degree.
C. and for 3 hours kept at this temperature and a pressure of 10
mbar. To the reaction solution are added at about 100.degree. C.
20.0 g of fluorotelechelic polyether sulfone (Mn.apprxeq.4,800,
according to .sup.1H-NMR, as described in II b)). The reaction
mixture is heated to 200.degree. C. and kept at a pressure of 100
mbar for 10 hours. The formed light-brown solution is poured into
five times as much water, with the product precipitating as a
voluminous gel. It is extracted cold with water several times,
until the extract no longer differs from water in term of pH value.
The product is syphoned off with a Buchner funnel and dried at
100.degree. C. and 10 mbar. The yield is 38 g (97% of theory). The
formed block copolymer has an Mn of about 13,100 (determined by GPC
light scattering) and the block length of the unsulfonated aromatic
polyether sulfones is about 30 repeating units. The degree of
sulfonation of the block copolymer is about 0.1 (according to
.sup.13C-NMR). This block copolymer was processed in polymer
mixtures with polyether sulfone into polymer films. The sequence of
the main chain at the block transitions between two adjacent blocks
of sulfonated and unsulfonated polyether sulfones is, according to
.sup.13C-NMR, the same as it is inside these blocks.
[0124] It could be shown that compared with films of polyether
sulfone and films of polymer mixtures of polyether sulfone and
sulfonated polyether sulfone with a comparable degree of
sulfonation, films of polymer mixtures containing the block
copolymer according to the invention have an improved compatibilty
with blood.
EXAMPLE 2
[0125] Block Copolymers of Hydroxytelechelic Polyether Sulfones and
Fluorotelechelic Sulfonated Polyether Sulfones
[0126] In a 100 ml Schlenk flask equipped with a magnetic stirrer
and a reflux condenser 1.71 g of hydroxytelechelic polyether
sulfone (Mn.apprxeq.6,100 according to .sup.1H-NMR, prepared as
described in II a)) are dissolved in 30 ml of N,N-dimethyl
acetamide at 60.degree. C. To this solution are added 0.033 g of
sodium carbonate and 1 ml water. After 30 minutes of stirring, 30
ml of toluene are added. The water and toluene are distilled off
completely with the aid of a distillation bridge, with the last
remaining toluene being driven out with dry nitrogen. To the
reaction solution are added at about 100.degree. C. 2.18 g of
fluorotelechelic sulfonated polyether sulfone (Mn.apprxeq.7,800
according to .sup.1H-NMR, as described in II d)). The reaction
mixture is heated under an atmosphere of dry nitrogen and a
superatmospheric pressure of 1 bar to 170.degree. C. and kept at
this temperature for 5 hours. The formed light-brown solution is
poured into five times as much acetone, with the crude product
precipitating as a white deposit. It is syphoned off and charged to
100 ml of water, with the powdery product strongly swelling in
water. Voluminous, transparent, clear hydrogel particles are
formed, which are extracted in cold water for 1 hour and are
syphoned off with a Buchner funnel. The aqueous extract is dialyzed
with water as dialyzate and freed of water by freeze drying.
Obtained is 0.57 g of a pulverulent, clear, tranparent substance as
side fraction. The formed 12.6 g of hydrogel are freed of water by
freeze drying followed by drying under high vacuum at 100.degree.
C. As main fraction, 1.94 g of a clear powder are obtained. The
total yield of the two fractions is 65%.
[0127] In the .sup.13C-NMR spectra of the block copolymers one
finds, in addition to the typical signals for C-atoms in the
sulfonated and unsulfonated blocks, also signals for C-atoms at the
block transitions. On the basis of the intensities of all signals,
the Mn of the blocks in the block copolymers can be calculated.
[0128] In the case of the main fraction-block copolymer, the Mn of
the sulfonated polyether sulfone block is.apprxeq.7,300, the Mn of
the unsulfonated polyether sulfone block is.apprxeq.8,800. Thus the
block length of the unsulfonated aromatic polyether sulfones is
about 38 repeating units. The degree of sulfonation of the block
copolymer is about 0.3 (according to .sup.13C-NMR). The
.sup.13C-NMR tests of the formed block copolymer show that the
sequence of the main chain at the block transitions between two
adjacent blocks of sulfonated and unsulfonated polyether sulfones
is the same as it is inside these blocks.
EXAMPLE 3
[0129] Block Copolymer of Hydroxytelechelic polyether Sulfone and
Sulfonated Monomer Units
[0130] In a Schlenk flask equipped with a magnetic stirrer and a
reflux condenser 5.00 g of bis(hydroxyphenyl)sulfone are dissolved
in 20 ml of 1,1-dioxothiolane at 60.degree. C. To this solution are
added 2.33 g of sodium carbonate and 5 ml water. After 30 minutes
of stirring 30 ml of chlorobenzene are added. The water and
chlorobenzene are distilled off completely with the aid of a
distillation bridge, with the last remaining chlorobenzene being
driven out with dry nitrogen. To the formed white suspension there
is added at 215.degree. C. a solution of 92.8 g of polyether
sulfone (Ultrason E6020P, BASF) in 400 ml of 1,1-dioxothiolane. In
order to completely exclude traces of water, the polyether sulfone
solution was subjected to azeotropic concentration with 100 ml of
chlorobenzene. The reaction mixture is kept under an atmosphere of
dry nitrogen at 215.degree. C. for 30 minutes, whereupon
hydroxytelechelic polyether sulfones are formed in situ. Next, 9.17
g of dry 3,3'-sulfonyl(6-fluorobenzene sulfonic acid) disodium salt
are added to the reaction mixture. The reaction mixture is kept at
215.degree. C. for another 6 hours.
[0131] The formed light-brown solution is poured into five times as
much acetone, with the crude product precipitating as a white
deposit. It is syphoned off, charged to 5 1 water, extracted in
cold water for 1 hour, and syphoned off with a Buchner funnel.
After drying in a vacuum drying cabinet at 110.degree. C. and 10
mbar, 97 g of clear product are obtained.
* * * * *