COVALENTLY CROSS-LINKED POLYMERS AND POLYMER MEMBRANES VIA SULFINATE ALKYLATION

POLYMERES ET MEMBRANES POLYMERE RETICULES DE FACON COVALENTE PAR ALKYLATION DE SULFINATE

English Abstract

The invention relates to a covalently cross-linked polymer or polymer membrane
consisting of one or more polymers, which can bear the following functional
groups (M=Hal (F, Cl, Br, I), OR, NR2; R=alkyl, hydroxyalkyl, aryl; (Me=H, Li,
Na, K, Cs, or other metal cations or ammonium ions); a) precursors of cation
exchange groups: SO2M and/or POM2 and/or COM b) sulphinate groups SO2Me and
which can be covalently cross-linked using the following organic compounds: a)
di, tri or oligofunctional haloalkanes or haloaromatics, which have been
reacted with sulphinate groups SO2Me, whereby the following cross-linking
bridges are present in the polymer/in the polymer blend/in the polymer
membrane (Y=cross-linking bridges, X=Hal (F, Cl, Br, I), OR, Y=(CH2)x-; -
arylene-; -(CH2)x-arylene-; CH2arylene-CH2-, x=3-12): polymer-SO2Y-SO2-polymer
and/or b) compounds containing the following groups: Hal-(CH2)x-NHR, one side
of which (Hal-) has been reacted with sulphinate groups SO2ME and the other
side (-NHR) with SO2M groups, whereby the following cross-linking bridges are
present in the polymer/in the polymer blend/in the polymer membrane: polymer-
SO2-(CH2)x-NR-SO2-polymer and/or c) compounds containing the following groups:
NHR-(CH2)x)-NHR, which have been reacted with sulphinate groups SO2Me, whereby
the following cross-linking bridges are present in the polymer/in the polymer
blend/in the polymer membrane: polymer-SO2-NR-(CH2)x-NR-SO2-polymer.

French Abstract

L'invention concerne un polymère ou une membrane polymère réticulés de façon covalente et composés d'au moins un polymère pouvant porter les groupes fonctionnels suivants (M=Hal (F, Cl, Br, I), OR, NR¿2?; R=alkyle, hydroxyalkyle, aryle; (Me=H, Li, Na, K, Cs, ou d'autres cations métalliques ou ions d'ammonium); a) précurseurs de groupes échangeurs de cations; SO¿2?M et/ou POM¿2? et/ou COM b) groupes de sulfoninate SO¿2?Me et qui peuvent être réticulés de façon covalente au moyen des composés organiques suivants: a) alcanes halogénés ou aromates halogénés di- tri- ou oligofonctionnels que l'on peut faire réagir avec des groupes de sulfinate SO¿2?Me, sachant que le polymère/le mélange polymérique/la membrane polymère renferment les ponts de réticulation suivants (Y=ponts de réticulation, X=Hal (F, Cl, Br, I), OR, Y=(CH¿2?)¿x?-; -arylène-; -(CH¿2?)¿x?-arylène-; CH¿2?arylène-CH¿2?-, x=3-12): polymère-SO¿2?Y-SO¿2?-polymère et/ou b) composés contenant les groupes suivants: Hal-(CH¿2?)¿x?-NHR mis, côté (hal-), en réaction avec des groupes de sulfinate SO¿2?ME, et de l'autre côté (-NHR) avec des groupes SO¿2?M, sachant que le polymère/le mélange polymérique/la membrane polymère renferment les ponts de réticulation: polymère-SO¿2?-(CH¿2?)¿x?-NR-SO¿2?-polymère et/ou c) composés contenant les groupes suivants: NHR-(CH¿2?)¿x?)-NHR mis en réaction avec des groupes SO¿2?Me, sachant que le polymère/le mélange polymérique/la membrane polymère renferment les ponts de réticulation suivants : polymère-SO¿2?-NR-(CH¿2?)¿x?-NR-SO¿2?-polymère.

Claims

20
CLAIMS:
1. Covalently cross-linked polymer or covalently cross-linked
polymer membrane comprising one or more polymers and
tectosilicates and/or phyllosilicates, wherein the tectosilicates
and/or phyllosilicates present can be functionalized or not
functionalised, wherein the polymers are characterized in that
they have the following functional groups:
a) precursors of cation exchange groups: SO2M and/or POM2 and/or
COM,
b) sulfinate groups SO2Me,
where M is independently Hal, OR or NR2, Hal is F, Cl, Br or I, R
is independently alkyl, hydroxyalkyl, or aryl, and Me is
independently H, Li, Na, K, Cs, another metal cation, or an
ammonium ion,
where said polymer is covalently cross-linked by the following
organic compounds:
c) difunctional, trifunctional or oligofunctional haloalkanes or
haloaromatics, which have been reacted with sulfinate groups
SO2Me, whereby the following cross-linking bridges are present in
the polymer/polymer blend/polymer membrane: polymer-SO2-Y-SO2-
polymer, where Y is -(CH2)x-; -arylene-; -(CH2)x-arylene-; or -CH2-
arylene-CH2-, where x is 3-12;
and/or
d) compounds containing the following groups: Hal-(CH2)x-NHR,
which have been reacted on the Hal- side with sulfinate groups
SO2Me and on the -NHR side with SO2M- groups, whereby the
following cross-linking bridges are present in the polymer/polymer
blend/polymer membrane: polymer-SO2-(CH2).-NR-SO2-polymer;
and/or
e) compounds containing the following groups: NHR-(CH2)x-NHR,
which have been reacted with SO2Me groups, whereby the following
cross-linking bridges are present in the polymer/polymer
blend/polymer membrane: polymer-SO2-NR- (CH2) x-NR-SO2-polymer .
2. Covalently cross-linked polymer blend or polymer blend
membrane according to claim 1, characterized in that the

21
tectosilicates and/or phyllosilicates are functionalized with a
reagent of general formula I and/or II:
<IMG>
wherein:
R1, R2, R3, R4 are independently from each other hydrogen, a
straight chain, branched, saturated or unsaturated hydrocarbon
radical with 1 to 40 carbon atoms, optionally substituted with at
least one functional group, or two of R1,
R2, R3 and R4 are
linked with each other forming a heterocyclic residue,
X represents phosphorous, nitrogen or carbon,
Y represents oxygen or sulfur,
n is an integer from 1 to 5, and
Z is an anion.
3. Covalently cross-linked polymer blend or polymer blend
membrane according to claim 2, wherein the straight chain,
branched, saturated or unsaturated hydrocarbon radical has 1 to 20
carbon atoms.
4. Covalently cross-linked polymer blend or polymer blend
membrane according to claim 2 or 3, wherein the straight chain,
branched, saturated or unsaturated hydrocarbon is substituted with
at least one functional group.
5. Covalently cross-linked polymer blend or polymer blend
membrane according to claim 2 or 3, wherein two of R1, R2, R3 and
R4, are linked together to form a heterocyclic residue.
6. Covalently cross-linked polymer blend or polymer blend
membrane according to claim 5, wherein the heterocyclic residue

2 2
has 5 to 10 carbon atoms.
7.
Covalently cross-linked polymer blend or polymer blend
membrane according to claim 5 or 6, wherein the heterocyclic
residue has one or more nitrogen atoms.
8. Covalently cross-linked polymer blend or polymer blend
membrane according to any one of claims 2 to 7, wherein n is 1 to
3.
9. Covalently cross-linked polymer blend or polymer blend membrane
according to any one of claims 2 to 8, characterized in that the
reagent with the general formula I and/or II comprises one or more
functional groups selected from hydroxyl groups, nitro groups,
sulfo groups, carboxylic acid groups or sulfonic acid groups,
sulfochloride groups, carbonic acid chloride groups, or any
combination thereof,
and wherein the anion Z is derived from a proton delivering acid.
10. Covalently cross-linked polymer blend or polymer blend
membrane according to claim 9, wherein the proton delivering acid
is a mineral acid.
11. Covalently cross-linked polymer blend or polymer blend
membrane according to claim 9, wherein the anion Z is chlorine,
bromine, fluorine, iodine, sulfate, sulfonate, phosphate,
phosphonate, phosphite or carboxylate.
12. Covalently cross-linked polymer blend or polymer blend
membrane according to claim 1, characterized in that the
tectosilicates and/or phyllosilicates are functionalized with
triphenylmethane dyes.
13. Covalently cross-linked polymer blend or polymer blend
membrane according to claim 1, characterized in that the membrane
contains triphenylmethane dyes.

23
14. Covalently cross-linked polymer blend or polymer blend
membrane according to claim 1 or 12 characterized in that the
tectosilicates and/or phyllosilicates are functionalized with
triphenylmethane dyes according to the following formula
<IMG>
or their precursor

24
<IMG>
wherein R contains C1-020 carbon atoms, 0-4 nitrogen atoms, and 0-
3 sulfur atoms, and wherein R optionally has a positive charge.
15. Covalently cross-linked polymer blend or polymer blend
membrane according to any one of claims 1 to 14, characterized in
that it is composed of the following polymers:
a) a polymer with at least SO2M groups
b) a polymer with at least SO2Me groups.
16. Covalently cross-linked polymer blend or polymer blend

25
membrane according to any one of claims 1 to 15, characterized in
that it consists of a polymer comprising the following groups:
SO2M groups and SO2Me groups.
17. Covalently cross-linked polymer blend or polymer blend
membrane according to any one of claims 1 to 16, characterized in
that the base polymer having the functional groups or the base
polymers having the functional groups is selected from the group
consisting of polyether sulfones,
polysulfones,
polyphenylsulfones, polyether ether sulfones, polyether ketones,
polyether ether ketones, polyphenylene ether,
polydiphenylphenylene ether, polyphenylene sulfide or copolymers
containing at least one of these components.
18. Covalently cross-linked polymer blend or polymer blend
membrane according to any one of claims 1 to 17, characterized in
that the following are used as base polymers: polysulfones,
polyphenylene ether or other polymers which can be lithiated.
19. Covalently cross-linked polymer blend or polymer blend
membrane according to any one of claims 1 to 18, characterized in
that the following are used as cross-linking agents: Hal-(CH2).-
Hal or Hal-CH2-phenylene-CH2-Hal (x = 3-12, Hal = F, Cl, Br, I).
20. Covalently cross-linked polymer blend or polymer blend
membrane according to any one of claims 1 to 19, characterized in
that the SO2M groups and/or POM2 groups and/or COM groups of the
polymer/polymer (blend) membrane are hydrolyzed to cation exchange
groups SO2Me and/or PO3Me2 and/or COOMe (Me = H, Li, Na, K, Cs or
other metal cations or ammonium ions) by one or more of the
following curing steps:
a) in 1-50 weight % aqueous alkali at T = RT - 95 °C,
b) in completely desalted water at T = RT - 95 °C,
c) in 1-50 weight % aqueous mineral acid at T = RT - 95 °C, and
d) in completely desalted water at T = RT - 95 °C.
21. Process for preparing covalently cross-linked polymers,

26
polymer blends or polymer blend membranes according to any one of
claims 1 to 20, characterized in that the polymers are dissolved
simultaneously or successively in a dipolar aprotic solvent that
is N,N-dimethylformamide, N,N-dimethylacetamide, N-
methylpyrrolidinone, dimethylsulfoxide or sulfolane, thereafter
the cross-linking agent is added, then the cross-linking agent is
homogeneously dispersed in the polymer solution by stirring,
thereafter the polymer solution is filtered and then degassed,
thereafter the polymer solution is then spread as a thin film on a
base, the solvent is then removed by heating to 80 - 130 °C and/or
by applying low pressure or in a circulating air dryer, wherein
the tectosilicates and/or phyllosilicates are added to the polymer
solution prior to the addition of the cross-linking agent.
22. The process of claim 21, wherein the polymer film is peeled
off the base after solvent removal.
23. The process of claim 21 or 22, further comprising curing the
polymer film by one or more of the following curing steps:
a) in 1-50 weight % aqueous alkali at T = RT - 95 °C,
b) in completely desalted water at T = RT - 95 °C,
c) in 1-50 weight % aqueous mineral acid at T = RT - 95 °C, and
d) in completely desalted water at T = RT - 95 °C.
24. The process of any one of claims 21 to 23, wherein said base
is a glass plate, metal plate, woven fabric, non-woven fabric or
other.
25. Use of the membrane defined in any one of claims 1 to 20 for
producing energy on an electrochemical route.
26. Use of the membrane defined in any one of claims 1 to 20 as a
component of membrane fuel cells at temperatures of from 0 to 180
°C.
27. The use according to claim 26, wherein said fuel cells are H2
or direct methanol fuel cells.

2 7
28. Use of the membrane defined in any one of claims 1 to 20 in
electrochemical cells.
29. Use of the membrane defined in any one of claims 1 to 20 in
secondary batteries.
30. Use of the membrane defined in any one of claims 1 to 20 in
electrolytic cells.
31. Use of the membrane defined in any one of claims 1 to 20 in a
membrane separation process.
32. The use according to claim 31, wherein said separation process
is gas separation, pervaporation, perstraction, reverse osmosis,
electrodialysis or diffusion dialysis.

Description

CA 02379962 2002-01-18 .
Covalently cross linked polymers and polymer membranes via
sulfinate alkyla ion
Description
Prior art
The author of t .s patent application has developed a new
method for prep .ing covalently cross-linked ionomer
membranes, whic is based on an alkylation reaction of
sulfinate group -containing polymers, polymer blends and
polymer (blend) membranes (J. Kerres, W. Cui, W.
Schnurnberger: 'Vernetzung von modifizierten Engineering
Thermoplasten", German Patent 196 22 337.7 (Application dated
June 4, 1996), carman Patent Office (1997), "Reticulation de
Materiaux ThermdpIastiques Industriels Modifies", French
Patent F 97 06716 dated May 30, 1997). An advantage of the
covalent networ is its resistance to hydrolysis even at
higher temperatires. A disadvantage of the ion conductive.
covalently cros -linked polymers and polymer blends described
in the above in ention is the formation of a hydrophobic
network when al ylating the sulfinate groups during forming
the membrane, t is hydrophobic network being partially
incompatible wi h the ion conductive polymer (blend)
component such =s a sulfonated polmer polymer-S03Me, so that
an inhomogeneou- polymer (blend) morphology is generated,
which reduces ti e mechanical stability (embrittlement on
drying up!) an. also prevents a complete cross-linking due to
the partial se.aration of sulfinate phase and sulfonate
phase.

CA 02379962 2010-02-19
2
Description
Thus, the object of the invention is to provide new covalently
cross-linked polymers/membranes in which the covalently cross-
linked polymer (blend) component is well compatible with the ion
conductive polymer (blend) component.
This object is achieved by providing covalently cross-linked
polymer or covalently cross-linked polymer membranes comprising
one or more polymers which optionally have the following
functional groups:
a) precursors of cation exchange groups: SO2M and/or POM2 and/or
COM,
b) sulfinate groups SO2Me,
where M is independently Hal, OR or NR2, Hal is F, Cl, Br or I, R
is independently alkyl, hydroxyalkyl, or aryl, and Me is
independently H, Li, Na, K, Cs, another metal cation, or an
ammonium ion,
where said polymer may be covalently cross-linked by the
following organic compounds:
c) difunctional, trifunctional or oligofunctional haloalkanes or
haloaromatics, which have been reacted with sulfinate groups
SO2Me, whereby the following cross-linking bridges are present in
the polymer/polymer blend/polymer membrane: polymer-S02-Y-S02-
polymer, where Y is - (CH2)x-; -arylene-; - (CH2)x-arylene-; or -
CH2-arylene-CH2-, where x is 3-12;
and/or
d) compounds containing the following groups: Hal-(CHAx-NHR,
which have been reacted on the Hal- side with sulfinate groups
SO2Me and on the -NIR side with SO2M- groups, whereby the
following cross-linking bridges are present in the
polymer/polymer blend/polymer membrane: polymer-S02- (CH2)-NR-S02-
polymer;
and/or

CA 02379962 2010-02-19
2a
e) compounds containing the following groups: NHR-(CH2).-NHR,
which have been reacted with SO2Me groups, whereby the following
cross-linking bridges are present in the polymer/polymer
blend/polymer membrane: polymer-
S02-NR- (CH2)x-NR-S02-polymer.
Further the process according to the invention adds to this
purpose.
Thereto a polymer solution comprising polymers containing the
following functional groups:
= sulfinate groups -S02Me
= sulfochloride groups and/or other precursors of cation
exchange groups,
is prepared.
Additionally, a bifunctional or oligofunctional alkylation cross-
linking agent (typically an a,w-dihaloalkane) and optionally a
secondary diamine cross-linking agent NHR(CH2)x-NHR is added to
the polymer solution. The formation of the covalent cross-linking
bridges takes place during formation of the membrane when
evaporating the solvent by alkylating the sulfinate groups and
optionally by the formation of sulfonamide via reaction of the
sulfohalogenide groups present in the polymer with the secondary
amino groups of the diamine cross-linking agent. During the
acidic and/or basic and/or neutral aqueous after-treatment of the
membranes following the membrane formation, the precursors of the
cation exchange groupings are hydrolyzed to form cation exchange
groups.
The present invention further provides a process for preparing
the above-mentioned covalently cross-linked polymers, polymer
blends or polymer blend membranes, characterized in that the
polymers are dissolved simultaneously or successively in a
dipolar aprotic solvent that is N,N-dimethylformamide, N,N-
dimethylacetamide, N-methylpyrrolidinone, dimethylsulfoxide or

CA 02379962 2010-02-19
2b
sulfolane, thereafter the cross-linking agent is added, then the
cross-linking agent is homogeneously dispersed in the polymer
solution by stirring, thereafter the polymer solution is filtered
and then degassed, thereafter the polymer solution is then spread
as a thin film on a base , the solvent is then removed by heating
to 80 - 130 C and/or by applying low pressure or in a
circulating air dryer, the polymer film is then optionally peeled
off the base and the polymer film is then cured as follows:
a) in 1-50 weight % aqueous alkali at T = RT - 95 C
b) in completely desalted water at T = RT - 95 C
c) in 1-50 weight % aqueous mineral acid at T = RT - 95 C
d) in completely desalted water at T = RT - 95 C,
wherein one or more of the curing steps may optionally be
omitted.
The present invention further provides a use of the membranes
defined above for producing energy on an electrochemical route.
The present invention further provides a use of the membranes
defined above as a component of membrane fuel cells at
temperatures of from 0 to 180 C.
The present invention further provides a use of the membranes
defined above in electrochemical cells.
The present invention further provides a use of the membranes
defined above in secondary batteries.
The present invention further provides a use of the membranes
definedabove in electrolytic cells.
The present invention further provides a use of the membranes
defined above in a membrane separation process
Figure 1 schematically shows the formation of the covalent cross-
linking bridges in blends of sulfochlorinated polymer

3
= =
and suifinated p-lymer, Figure 2 shows the formation of the
covalent cross-1 nking bridges in a polymer containing both
sulfinate groups and sulfochloride groups.
The composites a.cording to the invention consist of polymers
having the folio ing functional groups:
After membrane p eparation, before hydrolysis:
-502M and/or -P0M2 and/or -COM (M = Hal (P, Cl, Br, I),
OR, NR2; R I. alkyl, hydroxyalkyl, aryl)
= cross-linkin bridges:
a) polymer-S62-Y-502-polymer
optionally:
b) polymer-S*2-Y'-NR-S02-polymer
c) polymer-S.2-NR-Y1 '-NR-502-polymer
After hydrolysis:
= -503M-, -F0212-, -COOM-groupe
= above-menti.ned cross-linking bridges
The covalently .rose-linking of the aulfinate polymers in a
mixture with pr-cursors of cation exchange polymers results
in a better mix"ng of blend phases and thus a higher degree
of cross-linkin-, so as to achieve a better mechanical
stability of th, resultant polymer film compared to
covalently cros:-linked polymer (blend) films made from
cation exchange polymers and polymeric sulfinates. A further
improvement of he mechanical characteristics is achieved by
a controlled in orporation of a cross-linking component
containing amin. groups, which reacts with the precursors of
the cation exch.nge groups, into the polymer network.
A.-lication exa -lea
CA 02379962 2002-01-18

= 4 =
= =
The invention will be illustrated in more detail by two
examples as follcws. The weights/volumes of the components
used are listed in table 1.
1. Instruction for membrane preparation
sulfochlorin.ated PSU Udel (IEC=1.8 meg SO2C1/g) and PSUSO21ji
(IEC:=1.95 meg so;Li/g) (for polymer structures see figure 2)
are dissolved in N-methylpyrrolidinone (NMP) . Then ci.,o3-
diiodobutane is added to the solution of the cross-linking
agents. After stirring for 15 minutes the solution is
filtered and degp.ssed. A thin film of the polymer solution is
knife-coated ontb a glass plate. The glass plate is placed
into a vacuum drying oven and the solvent is removed at
temperatures of from 80 to 130 C at a low pressure of from
700 up to final y 15 mbar. The film is taken out of the
drying oven and cooled: The polymer film is peeled off the
glass plate underwater and is hydrolyzed/after-treated at
first in 10% hyd.rochloric acid and then in completely
desalted water at. temperatures of from 60 to 90 C for 24 h
respectively.
2. Used amounts of reactants and characterisation results
Table 1: Used amounts of reactants and characterisation
results
membrane Me PSU-S02C1 PSU-SO2Li cross-lin- TEC swelling Rsr
king agent
(g) [83 (nil] [me(1/8] [flam]
wz10 10 1 1 0.3 0.2 19.3 337.6
wz13 10 1 0.4 0.12 0.85 18.3 15.2
=
CA 02379962 2002-01-18

= 5
wz14 . -10 1 0.3 0.09 0.56 8.6 62.6
wz15 10 1 0.2 0.06 0.7 13 -36.14
wz16 10 1* 1* 0.3 0.75 11.7 31_6
* 2 SO2C1 groups per PSU repetitive unit
CA 02379962 2002-01-18

CA 02379962 2010-02-19
6
Part 2 of the application
Covalently cross-linked composite membranes
Prior art
The invention on which the present additional is based on relates
to a continuation or alternative to the German parent patent
application publication No. DE 100 24 575 Al (Kovalent vernetzte
Polymere und Polymermembranen via Sulfinatalkylierung).
The products and processes, respectively of this above-mentioned
parent application are subjected to the following disadvantages:
For membranes which are prepared by the described processes,
moistened gases are still needed for operation in the hydrogen
fuel cell. If the gases are not moistened, the membrane dries up
and the proton conductivity is decreased to a large extent.
To solve this problem, the present application suggests
incorporating tectosilicates and phyllosilicates which are
optionally functionalized according to the parent application,
particularly into a covalent network.
The parent application only describes the incorporation of
polymers into the covalent network. When using functionalized
phyllosilicates and/or tectosilicates it was surprisingly found,
that the compounds which have low molecular functional

CA 02379962 2010-02-19
7
groups and are bound to the phyllosilicates and/or tectosilicate
are not discharged during employment of the membrane, especially
in the case of employment in a hydrogen fuel cell. This allows an
increase in the concentration of ion conductive groups within the
covalent network without having the usual effect of extremely
deteriorating the mechanical characteristics of the membrane
(brittlement or strong swelling). In
an extreme case it is
therefore possible to completely eliminate the use of enclosed
ion conductive polymers in the covalent network. Ion conduction
then exclusively occurs via silicates having functional groups.
Thus, the present invention solves the problem of drying up the
membrane and of a limitation in the number of ion conductive
groups within the membranes to a not marginal extent.
Thus the object of the invention is to provide new covalently
cross-linked polymers/membranes displaying proton conductivity
even when used with gases which are not moistened or only
slightly moistened. Moreover, a further object is to incorporate
low molecular functionalized compounds which are coupled to a
silicate into the covalent network such that they remain in the
membrane for an industrially useful period time.
Further the process according to the invention helps to solve
this object.
The present invention further provides a covalently cross-linked
composite polymer or covalently cross-linked composite polymer
membrane comprising one or more polymers and tectosilicates
and/or phyllosilicates, wherein the tectosilicates and/or
phyllosilicates present can be functionalized or not
functionalised, wherein
the polymers are characterized in that they may have the
following functional groups:
a) precursors of cation exchange groups: SO2M and/or POM3 and/or
COM,

CA 02379962 2010-02-19
7a
b) sulfinate groups SO2Me,
where M is independently Hal, OR, or NR2, Hal is F, Cl, Br or I, R
is independently alkyl, hydroxyalkyl or aryl, Me is independently
H, Li, Na, K, Cs, another metal cation, or an ammonium ion,
said polymers may be covalently cross-linked by the following
organic compounds:
C) difunctionial, trifunctional or oligofunctional haloalkanes or
haloaromatics which have been reacted with sulfinate groups SO2Me,
whereby the following cross-linking bridges are present in the
polymer/polymer blend/polymer membrane: polymer-S02-Y-S02-polymer
where Y is the cross-linking bridge: -
(CH2)õ-; -arylene-;
-(CH2)x-arylene-; or -CH2-arylene-CH2-, where x is 3-12
and/or
d) compounds containing the following groups: Hal- (CHAx-NHR,
which have been reacted on the Hal- side with sulfinate groups
SO2Me and on the -NHR side with SO2M groups, whereby the following
cross-linking bridges are present in the polymer/polymer
blend/polymer membrane: polymer-S02- (CH2) x-NR-S02-polymer;
and/or
e) compounds containing the following groups: NHR-(CH2)x-NHR,
which have been reacted with SO2Me groups, whereby the following
cross-linking bridges are present in the polymer/polymer
blend/polymer membrane: polymer-S02-NR- (CH2) x-NR-S02-polymer .
Description of the invention:
The following text expressively refers to the parent patent
application publication No. DE 100 24 575 Al:

8
1
=
A mixture in a s itable solvent, preferably an aprotic one,
is prepared, whi.h contains polymers and functionalized
tectosilicates ad/or phyllosilicates and optionally low
molecular compouuds.
The mixture cont ins polymers and the following functional
groups;
= sulfinate gr.ups SO2Me (Me is a monovalent or polyvalent
metal cation
= sulfochlorid- groups and/or other precursors of cation
exchange gro ps.
Additionally, a -ifunctional or oligofunctional alkylation
cross-linking ag nt (typically an a,m-dihaloalkane) and
optionally a sec-ndary diamine cross-linking agent NUR-
(Cliz)x-NTIR is ad.ed to the mixture, preferably a polymer
solution. The f-rmation of the covalent cross-linking bridges
takes place dur'ng the formation of the membrane when
evaporating the solvent by alkylating the sulfinate groups
and optionally formation of sulfonamide via reaction of
the sulfohalide groups present in the polymer with the
secondary amino groups of the diamine cross-linking agent.
During the acid'c and/or basic and/or neutral aqueous after-
treatment of th. membranes following the formation of the
membrane the pr cursors of the ion exchange groupings are
hydrolyzed and oxidized to form ion exchange groups,
respectively.
Figure 1 schema ically shows the formation of the covalent
cross-linking b idges in blends of sulfochlorinated polymer
and sulfinated -olymer, Figure 2 shows the formation of the
covalent cross-linking bridges in a polymer containing both
- sulfinate group= and sulfochloride groups.
CA 02379962 2002-01-18

9
The composites a.cording to the invention consist of polymers
having the folio ing functional groups:
After membrane p eparation, before hydrolysis:
= S02101 and/or !0M2 and/or CoM (M m Hal (F, Cl, Br, I), OR,
Nit, R=alkyl, hydroxyalkyl, aryl)
= cross-linkin bridges;
a) polymer-S=2-Y-S02-polymer
optionally:
b) polymer-S02-Y'-NR-S02-polymer
c) polymer-S=2-NR-Y"-NR-S02-polymer
After hydrolysi_:
= -S03M, -1,03M -COOM groups
= above-menti.ned cross-linking bridges
By covalently c oss-linking the sulfinate polymers mixed with
precursors of i.n exchange polymers, especially cation
exchange polyms.s, in the presence of functionalized
phyllosilicates and/or tectosilicates a better mixing of the
blend phases an. thus also a higher degree of cross-linking
is achieved, gi,ing raise to a better mechanical stability of
the resultant p-lymer film compared to covalently cross-
linked polymer blend) films made of cation exchange polymers
and polymeric s if mates. By a controlled inclusion of a
cross-linking c.mponent having amino groups, which reacts
, 25 with the precur.ors of the cation exchange groups, into the
polymer network a further improvement of the mechanical
characteristics is achieved.
By incorporati functionalized tectosilicates and/or
phyllosilicate into the covalent network during the
formation of t e membrane, the water retention capability of
the membrane i. increased. The functional groups protruding
from the surfa.e of the functionalized tectosilicates or
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10
=
phyllosilicate, additionally change the membrane
characteristics in accordance with their functionality_
Description of the inorganic filler
The inorganic active filler is a phyllosilicate based on
montmorillonite, smectite, illite, sepiolite, palygorskite,
muscovite, allevardite, amesite, hectorite, talc,
fluorhectorite, saponite, beidelite, nontronite, stevensite,
bentonite, mica, vermiculite, fluorvermiculite, halloysite,
fluor containing synthetical talc types or blends of two or
more of the above-mentioned phyllosilicates. The
phyllosilicate can be delaminated or pillared. Particularly
preferred is montmorillonite.
The weight ratio of the phyllosilicate is preferably from 1
to 80 %, more preferably from 2 to 30 % by weight, most
preferably from 5 to 20 %-
If the functionalized filler, especially zcolites and members
of the beidelite series and bentonites, is the only ion-
conducting component, its weight ratio is usually in a range
of from 5 to 80 wtVs, preferably of from 20 to 70 wt% and
especially in a range of from 30 to 60 wt%-.
Description of the functionalized phyllosilicate:
The term "a phyllosilicate" in general means a silicate, in
which the SiO4 tetraeders are connected in two-dimensional
infinite networks. (The empirical formula for the anion is
. The single layers are linked to one another by
the cations positioned between them, which are usually Na, K,
Mg, Al or/and Ca in the naturally occurring phyllosilicates.
By the term "a delaminated functionalized phyllosilicate" we
understand phyllosilicates in which the layer distances are
at first increased by reaction with so-called
functionalisation agents. The layer thickness of such
silicates before delamination is preferably 5 to 100
angstrom, more preferably 5 to 50 and most preferably 8 to 20
angstrom. To increase the layer distances (hydrophobisation)
. .
- . -
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11 =
=
the phyllosilica es are reacted (before production of the
composites acco .ing to the invention) with so-called
functionalizing Iydrophobisation agents which are often also
called onium io s or onium salts.
The cations of -he phyllosilicates are replaced by organic
functionalizing hydrophobisation agents whereby the desired
layer distances which depend on the kind of the respective
functionalizing molecule or polymer which is to be
incorporated inio the phyllosilicate can be adjusted by the
kind of the org:nic residue.
The exchange of the metal ions or protons can be complete or
partial. Prefe red is the complete exchange of metal ions or
protons. The = entity of exchangeable metal ions or protons
is usually expr ssed as milli equivalent (meq) per 1 g of
phyllosilicate tectosilicate and is referred to as ion
exchange capaci y.
Preferred are p yllosilicates or tectosilicates having a
cation exchange capacity of at least 0,5, preferably 0,8 to
1,3 meq/g.
Suitable organ'c functionalizing hydrophobisation agents are
derived from o onium, ammonium, phosphonium and sulfonium
ions, which ma carry one or more organic residues.
As suitable fu ctionalizing hydrophobisation agents those of
general formul- I and/or II are mentioned:
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12
=
ne
Z naz n8
R3- -R2
R3. MR2
I IX
-
Where the subst'tuents have the following meaning:
'5 R1, R2, R3, R4 -re independently from each other hydrogen, a
straight chain, branched, saturated or unsaturated
hydrocarbon rad'cal with 1 to 40, preferably 1 to 20 C atoms,
optionally carr ing at least one functional group or 2 of the
radicals are ii ed with each other, preferably to a
heterocyclic re idue having 5 to 10 C atoms, more preferably
having one or -re N atoms.
X represents ph.sphorous, nitrogen or carbon,
Y represents ox gen or sulfur,
n is an integer from 1 to 5, preferably 1 to 3 and
Z is an anion.
Suitable functi=nal groups are hydroxyl, nitro or sulfo
groups, whereas carboxyl or sulfonic acid groups are
especially pref-rred. In the same way sulfochloride and
carboxylic aci, chloride groups are especially preferred.
Suitable anion- Z are derived from proton delivering acids,
in particular ineral acids, wherein halogens such as
chlorine, brom ne, fluorine, iodine, sulfate, sulfonate,
phosphate, pho phonate, phosphite and carboxylate, especially
acetate are pr ferred. The phyllosilicates used as starting
materials are -enerally reacted as a suspension. The
preferred susp-nding agent is water, optionally mixed with
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=
alcohols, especi-lly lower alcohols having 1 to 3 carbon
atoms. If the f nctionalizing hydrophobisation agent is not
water-soluble, len a solvent is preferred in which said
agent is solubl.-,. In such cases, this is especially an
aprotic solvent. Further examples for suspending agents are
ketones and hyd.ocarbons. Usually a suspending agent
miscible with w-ter is preferred. On addition of the
hydrophobizing -gent to the phyllosilicate, ion exchange
occurs whereby .he phyllosilicate usually precipitates from
the solution. he metal salt resulting as a by-product of
the ion exchang is preferably water-soluble, so that the
hydrophobized poyllosilicate can be separated as a
crystalline sol d, for example, by filtration.
The ion exchang- is mostly independent from the reaction
temperature. T e temperature is preferably above the
crystallization point of the medium and below the boiling
point thereof. For aqueous systems the temperature is
between 0 and 100 C, preferably between 40 and 80 C.
For a cation a - anion exchange polymer alkylammonium ions
are preferred, in particular if as a functional group
additionally a carboxylic acid chloride or sulfonic acid
chloride is pr-sent in the same molecule. The alkylammonium
ions can be ob.ained via usual methylation reagents such as
methyl iodide. Suitable ammonium ions are omega-
aminocarboxyli. acids, especially preferred are omega-
aminoarylsulfo ic acids and omega-alkylaminosulfonic acids.
Omega-aminoary sulfonic acids and omega-alkylaminosulfonic
acids can be o.tained with usual mineral acids, for example
hydrochloric a.id, sulfuric acid or phosphoric acid or by
methylation re.gents such as methyl iodide.
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Additional prefe red ammonium ions are pyridine and
laurylammonium i.ns. After hydrophobizing the layer distance
of the phyllosil:cates is in general between 10 and 50
angstrom, prefer=bly 13 and 40 angstrom.
The hydrophobize. and functionalized phyllosilicate is freed
of water by dryil g. In general a thus treated phyllosilicate
still contains - residual water content of 0-5 weight % of
water_ Subsequ=ntly the hydrophobized phyllosilicate can be
mixed in form oi a suspension in a suspending agent which is
free as much as possible from water with the mentioned
polymers and be further processed to obtain a membrane.
An especially p,eferred functionalization of the
tectosilicates -ndfor phyllosilicates is, in general,
achieved with ma.dified dyes or their precursors, especially
with triphenylm-thane dyes. They are represented by the
general formula
R4
NN.10
-s%R4
.NS,%, 1110
111111
R4
R = alkyl (essecially CH3; CiRO
In the present invention dyes derived from the following
basic skeleton are used:
=
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=
*
R contains Ci-- C40, and 0-4 N-atoms, and 0-3 S-atoms, R can
be charged positively.
S In order to functionalize the phyllosilicate the dye or its
reduced precursor is sufficiently stirred in an aprotic
solvent (e,g. tetrahydrofuran, DMAc. NM?) together with the
silicate in a vessel. After 24 hours the dye and the
precursor, respectively, is intercalated into the cavities of
the phyllosilicate. The intercalation must be such that the
ion conductive croup is located on the surface of the
silicate particle.
The following figure schematically shows the process:
R¨..õ
cit;C.A.kt
)401. dye
111.111
ptett...S.Seht
1
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CA 02379962 2010-02-19
16
The thus functionalized phyllosilicates is added as an additive
to the polymer solution as described in application publication
No. DE 100 24 575 Al. It was found to be especially preferable
to use the precursor of the dyes.
Only in the acidic after-
treatment the dyes themselves are formed by splitting off water.
0
=H J
RN
./R 1111
R
449
=
1110
In the case of the triphenylmethane dyes it was hereby
surprisingly found that these dyes support the proton
conductivity in the membranes prepared thereby. Whether this is
even a water-free proton conductivity cannot be stated with
sufficient certainty. If the dyes are not bound to the silicate,
thus if they are present in the membrane in a free form, they are
discharged from the fuel cell with the reaction water already
after a short period of time.
According to the invention the polymer blends containing
sulfinate groups of the above-mentioned parent application, most
preferably the thermoplatic functionalized polymers (ionomers)
are added to the suspension of the hydrophobized phyllosilicates.
This can be done by using an already dissolved form or the
polymers are solubilized in the suspension itself.
Preferably
the amount of the

17 =
phyllosilicates s of from 1 to 70 weight %, more preferably
of from 2 to 40 eight Ps and most preferably of from 5 to 15
weight %.
A further improv-ment with respect to the parent patent
application can -e the additional blending of zirconyl
chloride (ZrOC12 into the membrane polymer solution and into
the cavities of he phyllosilicates and/or tectosilicates. If
the after-treat -nt of the membrane is performed in
phosphoric acid, hardly soluble zirconium phosphate
precipitates in the direct proximity of the silicate grain in
the membrane. Z'rconium phosphate shows self-proton
conductivity wh.n operating the fuel cell. The proton
conductivity aces through the formation of hydrogen
phosphates as i termediate steps and is part of the state of
the art. A cont,olled inclusion in the direct proximity of a
water storing a.ent (silicates) is novel.
1. Etrbodiment for membrane preparation
Su1foch1orinate4 PSU Udell (IECa1.8 meg sO2c1/g) and PSUSO2Li
(IEC1.95 meg SPiLi/g) (for polymer structures see figure 2)
and montmorillo ite functionalized with triphenylmethane dye
are dissolved i N-methylpyrrolidinone (Nmp). Then a,ca-
diiodobutane as a cross-linking agent is added to the
solution. After stirring for 15 minutes the solution is
filtered and desassed. A thin film of the polymer solution is
knife-coated o o a glass plate. The glass plate is placed
into a vacuum ing oven and the solvent is removed at
temperatures o from 80 to 130 C at a low pressure of from
700 up to fina ly 15 mbar. The film is taken out of the
drying oven an. cooled. The polymer film is peeled off the
glass plate un-erwater and is hydrolyzed/after-treated at
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first in 10% hyd.ochloric acid and then in completely
desalted Water a. temperatures of from 60 to 90 C for 24 h,
respectively.
2. Embodiment
Sulfochlorinated PSU Udell (IBC-1.2 meg S02C1/g) and PSUSO2Li
(IBC.1.95 meg SO Li/g) and montmorillonite treated with a,0-
aminoalkylsulfoc bride (with sulfochloride groups facing to
the outside) are dissolved in N-methylpyrrolidinone (414P).
Then the cross-linking agent a,w-diiodobutane is added to
the solution. Af er stirring for 15 minutes the solution is
filtered and deg,ssed and processed to a membrane as
described in exa pie 1.
This membrane h-s a higher IEC value after curing than a
control without the functionalized phyllosilicate.
3. Embodiment
Sulfochlorinate. PSU Udele (IBC.1.8 meg SO2C1/g) and PSUSO2Li
(IBC-1.95 meg Se2Li/g) (for polymer structures see figure 2)
and montmorillo ite treated with zirconyl chloride are
dissolved in di ethylsulfoxide (DMSO).
The dissolution takes place in the following order: First
montmorillonite K10 is suspended in DMSO and 10 weight t
zirconyl chlori.e, based on the total membrane amount, is
added. Then the other polymer components are added. Then the
cross-linking a:ent m,o-diiodobutane is added to the
solution. After stirring for 15 minutes the solution is
filtered and de=assed. A thin film of the polymer solution is
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=
knife-coated onto a glass plate. The glass plate is placed
into a vacuum drying oven and the solvent is removed at
temperatures of from 80 to 130 C at a low pressure of from
700 up to finally 15 mbar. The film is taken out of the
drying oven and cooled. The polymer film is peeled off the
glass plate under phosphoric acid and stored in phosphoric
acid at a temperature of between 30 and 90 C for about 10
hours and then optionally further hydrolyzed/after-treated in
10% hydrochloric adid and then in completely desalted water
at temperatures of from 60 to 90 C for 24 h respectively.
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