CA2215911C

CA2215911C - Polymer electrolytes and process for their preparation

Info

Publication number: CA2215911C
Application number: CA002215911A
Authority: CA
Inventors: Joachim Clauss; Gregor Deckers; Arnold Schneller; Helmut Witteler
Original assignee: BASF Fuel Cell GmbH
Current assignee: BASF Fuel Cell GmbH
Priority date: 1995-03-20
Filing date: 1996-03-19
Publication date: 2008-05-20
Anticipated expiration: 2016-03-19
Also published as: JP4062364B2; EP0815160A1; JPH11502249A; WO1996029360A1; CA2215911A1; EP0815160B1; DE59611465D1

Abstract

A sulfonated aromatic polyether ketone of the formula (II) [[Ar-O-]p -Ar'-]x-O-Ar]m-[CO-Ar'-]y-[O-Ar-]n-CO-]
(II) in which from 1% to 100% of the O-phenylene-CO units are substituted with an SO3M group, with sulfonated and unsulfonated O-phenylene-CO units and sulfonated and unsulfonated O-phenylene-O units being able to be in any desired sequence with respect to one another, and where Ar, Ar' , M, x, n, m, y and p are, defined as follows:
Ar is a phenylene ring with para and/or meta bonds, Ar' is a phenylene, naphthylene, biphenylylene or anthrylene unit or another divalent aromatic unit, x, n and m independently of one another are 0 or 1, y is 0, 1, 2 or 3, p is 1, 2, 3 or 4, and M, taking into account the ionic valencies, comprises one or more elements selected from the following group : H, NR4 +, where R = H or C1-C4-alkyl, or a metal, preferably an alkali metal or alkaline earth metal or a metal from subgroup 8, with the exception of the combination p=1, m=0, Y=2, n=1.

Description

19 SEP '97 14:23 HOE PATENT-U.LIZ.ABT 06930581255 S.3 ~ -- , ~-.7 WO 96/29360 PCT/EP96/01177 SULFONATED POLYETHER K~TONES, PROCESS FOR TFlEIR
PREPARATION AND USE FOR THE PRODL7CTION OF NM+LElRANES
De~criptioa _ The- iavention relates to polymer el.ectrolytes comprising a. sul.f.onatied aromatic polyether ketoae, to a. procees for their., preparati.on, to the use of these polyme= electro-lytes and to solutions of.these poLymer electrolytes and the use thereof.
4 , Sulfonated polyether ketones constitute cationic ion exchangers. They are ueefu7,' as menabrane materials, for example for ultrafiltration, for desa].ination and for the ramoval of microorganisms, since in many cages they are mechanically stabla even in the pregence of water.
Sulfonated polyether ketones are proton- and cation-ccnducting materia].s which axe useful for electrodialygis or as a component of electrochemical ca7.ls.

Starting materials are aromatic polyethar ketones as indicated by the formula (2) [ [Ar-O-3 qAr- ( [CO-Ar' -] =-o-Ar1 .- iCO,Ar' -] t- [p-Ar-] u-CO-3 (I?
in which Ar is a phenylene ring with para and/or meta bonds, Ar' is a phenylene, naphthylene, biphenylylene or anthrylene unit or another divalent aromatic unit, r, u and=s independently of one another are 0 or 1, t is 0, 1, 2 or 3, and q ie l, 2, 3 or 4.
The pollriner where q-1, rs0, s"l., t=;0 and u=0 fca commex-cial.ly available u.ndex the name Vl.ctrex~ff', The polymer UZ:[.C;:r,Z~AT. ,'.70GLr~?~,NZ'.~

19 SEP '97 14:23 HOE PATENT-U.LIZ.ABT 06930581255 S.4 where q=1, r-0, s=0, t-0 and u=0 is ],ikewise produced by Victrex. Furthermore, the polymer where q=1, r=0, 0=0, t!=2, ua 1 and Ar ig 1,4-phenylene is commercially available under the.name D'ltrapek .

Polyether ketonee are readily accessible. They ca= be synthesized in prizzcip7.e by an eletrophilic Friedel-Crafts polycondensation reaction, in which an appropriate aromatic bis-acid dihalide is raacted with. an arcmatic ether. This possibility is described, for example, in IIS-3 065 205, GB-971 277, US-3 441 538, GB-1 387 303. arsd WO 84-03891 and in the paper by Iwakura, Y., Uno, X. and Tahiguchi, T.J., Polym. Sci., Pat. A-1, 6, 3345 (1968).
In addition, the ether ketones can be obtained by nucleo--philic aromatic, subatittition. To this end an appropriate arornatic bisdiol ig reacted with an aromatic bis-haloketone, as described for example irn:
R.A. Clendinning, A.G. Farnhant, -W.F. Hall, R.N. Johnson and C.N. Merriam, J. Polym. Sci. Al, 5, 2375, (1967), GS-1 177 183, GB-1 141 421, EP-0 001 879, US 4],08 837, US 4 175 175, T.E. Attwood, A.B. Newton, J.B. Rose, Br:
Polym. Journ., 4, 391, (1972); T'.E. Attwood, P.C. Dawson, J.L. Freeman, L.R.J. Roy, J.B. Rose, P.A. Staniland, Polyamer, 22, 1096, (1981).

The preparation of sulfoxxated polyether ketones from some of these polyether ketones is described in Ep-A-008 895, EP-A-041 780 and EP-A-575 807.

According to EP-A-008 895, the polymer to be sulfonated is suspanded at roozn tamperature in 98% strength by weight sulfuric aaid. The dissolution procegs an,d the sulf'onation take place si.multaneousl.y, to give, gradually, a highly viscous solution. Thi.s solution ia either left as it is or diluted at the same temperature with sulfuric acid of the saxne coneentration.. The reac-rian progresses very slowly. Not until after 10 we ks war..c about 90% of the guJ.fonatable plzeny'J..tne units su1fonal:ed. Xn the ;poyy'a-L:ze:r ketones etiployod,, the, 19 SEP '97 14:23 HOE PATENT-U.LIZ.ABT 06930581255 S.5 numexical ratio of ether bridges to Co bridgee was approximately 2:1.. According to EP-A-008 895, under these ooaditions only O-phenylene-O units are sulfonated.
According to the process of EP-A-041 780, aromatic polyether ketoneg which. cQrrstitute copolymers are sul-, fonated at e7.evated temperatu're. Onll! some of the monomer units (A) are suscQptib7.e to sulfonation, while other monomer units (H) are not sulfonated. Thus the degree. of sulfonation can be controlled by the ratio A/9. However, here too the zeaction conditions remain unchanged during the dissolution procose and thereafter. Corresponding homopolyiners (A) would under the conditione inda.eated= be sulfonated to an excescive degrea and would therefore lead to water-solubie compounds. Since in this case sulfonati.on takes place during the actual dissolution proceao of the polymer, it is difficult to control the degree of sulfonation and. to obtain low-sulfonated products. In the proceso according to EP-A-041 780, likewise, under these conditions only O-phenylene-O units are sulfonated.

In the case of the pxoc ss disclosed in EP-A-575 807, the polymer to be sulfonated is suspended at room temperature in 94 to 97% strength by weight sulfuric acid. The dissolution procegs and partial sulfonation of the poZymer take place simultaneously to give, gradually, a viscous solution. A su7,fonating agent is added to the solution until the concentration of sulfuric acid is from 98 to 99 .9 % by weight. The golutioz3, is held until the desired degree of sulf_onation is reached' and. is then worked up. Under these conditions, only O-phenyXene-O
uzlits are su].fonated, whi].e 0-phenylene-CO units remain unatracked. This is also confirmed by Daoust et al.
(Polymer, Vol. 35 (25), 5491-5497 (1994) ), where the sulfonation procegs is Ximited to one sulfonic acid group per repeating unit and to one of the four ecluivaleznt pos5_ti.o:xa of thQ phenylene riziJ r~urx'ounded by two etkler .",i'he r)tltier two phenyJ_erin r.-iri,gs are, accordiz::; to _ a. -I)aoust, so highly deactivated by the neighboring ketone unit that no sulfonation takes place here.

_n the case of the sulfonation. of polyether ketones using chlorosulfonic acid or using a S03/triethyl phosphate complex, a high degree of crosslinking and of decomposi-tion of the polymer mai.= chain i.s observed (Marvel. et al. , Journal of. Polymer Science, Polymer Chem.
E.dition, vol. 23, 2205-2223 (1985) and Bishop et al., Macromolecules, vol. 18, 86-93 (1985)).

:Cn the prior art p.rocesses, only O-phenylene-O units in the polyether_ ketones employed. are sulfonated, while cD-phenylene-CO units and CO-phenylerne-CO units are sulfonated either not at all or only to an extremely iainimal extent, or, if more severe conditions are em-ployed, crosslinking takes place or the polymer main chain is destroyed. Polymers which do not have O-phenylene-O units cannot be sulfonated to any signifi-cant extent. The products obtained when relatively severe :reaction conditions are employed are insoluble in the customary solvents and can therefore not be processed further from solution, or only with very great diffi-<<u l ty .

According to the prior art it was not to be expected. that O-phenylene-CO units in a polyether ketone could be sulfonated. Likewise, the prior art gave no reason to axpect that correspondingly sulfonated products would he soluble in customary solvents. It was regarded, in the ;orior art, as impossible to achieve gentle sulfon.ati.on, in a polyether ketone, of phen.ylene rings directly ,:.djG"cent to a keto group without at the same time ex-periencing crosslinking= or the breakdov,m of the polyner main chain.

'I'he present invention provides a gentle and controllable process for the sulfonation of polyether ketones of the f'ormula (I), which J .i process makes it possible to sulfonate not only O-phenylene-O units but also 0-phenylene-CO units and, in this way, to obtain novel sulfonated polyether ketones.
A further object-is to prepare solu.tions of these.poly-mers.

It has surprisingly now been found that polymers accord-ing to the invention can be sulfonated well in a control-lable manner at not only the O-phenylene-O units but also the- O-phenylene:-CO units, with the products- obtained evern being soluble- above a certain degree- of sulfonation. Even polymers which comprise only 0-phenylene-CO units are accessible to targeted sulfonation.

The present invention therefore provides a sulfonated aromatic polyether ketone comprising units of the formula (II) [[Ar-O-] P-Ar [[CO-Ar' -1 x-O-Ar] m- jC0-Ar' -] y- [O-Ar-] n-CO-1 (2z) in which from 1% to 100% of the O-phenylene-CO units are substituted with an S03M group, with sulfonated and unsulfonated 0-phenylene-CO units and sulfonated and unsulfonated O-phenylene-0 units being able to be in any desired sequence with respect to one another, and where Ar, Ar', M, X. n, m, y and p are defined as follows:
Ar is a phenylene ring with para and/or meta bonds, xr' is a phenylen.e, naphthylene, bip}.ienylylene or anthrylexie unit or another divalent aromatic unit, x, T-i and n1 independently of one another are 0 or 1, y is 0, l, 2 or 3, is 1, 2, 3 or 4, an.d.
lK, taking into account the ionic valencies, comprises one or more elements selected from the following group: H, NR4+, where R= H
or C,,-C4-alkyl, or a metal and particularly an alkali metal or ialkaline earth metal or a metal from subgroup 8, and is 19 SEP '97 14:25 HOE PATENT-U.LIZ.ABT 06930581255 S.8 preEerably H, NR4+, Na, K, Ca, Mg, Fe or pt.

The present invention likewise provides a process for the preparation of theae sulfonated polyether ketones having-units of the form,ula (II), and polymer electrolyte solutions comprisirg said.polymeza, and also provides ~cr the use of such polymer electrolyte-solutions.

With the aid of the proaess accarding to the invesztion. it.
ie. poasible to sulforlate aromatic polyether ketones having units of the- f.ormmula (I) even at the O-pheslylener, l0 co units.

In agreement with the published literature it ie found that sulfonation takes place preferentially at =the O-phenylene-O units of the polyether ketones. It. has surprisirngly been found that by the process according to the S.nvention a szgn.ifi.caxit proportion of the 0-phenylene-CO units as well is sulfanated, with relatively high degrees of sulfonation.

The proaess comprises dissolving the aromatic po].yether ketone in 94 to 98% strength by weight sulfuric acid, adding a sulfonating agent to the solution obtained un.til, the coxzcentration of sulfuric acid is from 98 to 100% by r-:
~-; weight or until the concentratiorn of oleum is from 0.01 to 15% by weight of SO3, eatablishing a suitable reaction temperature and working up the reaation mixture as soon as the desired degree of sulfonation is reached.

The aromatic polyether ketone iB preferably dissolved in sulfuri.c acid under gexltle conditions, i.e. under condi-tioxzs in which sulfonation is largely suppressed vr does not yet occur. The concentration of the sulfuri_o acid ased for dissolution is preferably from 94 to 97% by weight. The dissol.utiori tentperatuze chosen is as low as possible, in order substaritially to avoid coznmencement of the sulfonatiolz reaction at this stage. In gpn.eraJ.,, the cl ~;r_aOJ.ut~On tiexnp ~'atLl.r? ~* 2:)r tV:'er>_n 10 axl.ti. QO C;, :i_~

19 SEP '97 14:25 HOE PATENT-U.LIZ.ABT 06930581255 S 9 particular between 20 and 70 C and, preferably, between 30 and 60 C.

A13. of the divalent aromatic radicals Ar and Ar' of the polymer to be sulfoaated are, in particular, phenyletie, pref-erajaly 1,4-phenylene.

xt is pr.eferzed to emplQy homopolymers of tha fonaulae (IYI), (IV) and (V), so that. the resulting polyether ke.tone according to the inventioa comprises sulfonated unite of. these formul.ae. 'Under controllad conditions, th .
sulfonatiors proceBm degcribed $ermits the sulfonation.o~
polyether ketones even at O-phenylene-CO units.

~' .
~~ ~ ~ ~ ~ I 1 1 }

r= ' ! V 1 ~. .-..
~=' Y (V
O

In a further preferred e:abodixnent, the polyether ketone to be sulfonat-ed is a copolyrcie:r Gompz'ising at least two dif_~erent vxlit.s of tl4e foz-mulae (11), (IV), (V) and ( V I ) .

19 SEP '97 14:26 HOE PATENT-U.LIZ.ABT 06930581255 5.10 ~ ~ !~'; ~ ~V1 ) For the homopolymer of the formula (III), for example, after a disaolution procedure at not. more, thaa 80 C a=d after 5 h at roo:n temperature in 95 or 97% strength by weig2zt. oulfuric acid, degrees of sulfonation of lees than 14 mol% are observed, based on.one repeating unit..

For the homopolymer of the formula (IV) , for example, after a disaolution procedure at nat more than 80 c and after 2.4 h at r.oom temperature in 95 or 97% strength by weight sulfuric acid and at a su].fonation te,uiperature in the range from 30 to 900C, degrees of sulfonation of about 25 mo3.t are obeezved, based on one repeating unit.
For the homopolymer of the formula (V), for example, after a dimeo3.ution procedure at 80 C and after 24 h at room temperature in 95 br 97% strength by weight sulfuric acid, a degree of sulfonation of 12 mo1% is observed, baBed an one repeating unit. The oulfonation teanperature ia preferably in the range from 50 to ],00 C.

Preferred dissolution Conditions are those leading to a degree of sulfornation of not more than 35 molo baged on one repeating unit. During the disaolution process, sulfonation of the main chain is largely Buppressed.
lnvest.igstiona have shown that no breakdown occurs during the dissolution process.

As the sulfonating agent used to increase the concentra-tion of su3.furia acid and to carzy out sulfoz'lation, preferenca is givezi tc-) empJ,oying sulfuric acid, fuming sul.fu.ri.c aCid, oleuici, chlar,=osulfonia acid Ernd suJ_f.ui:
tr_ i.oxide.

19 SEP '97 14:26 HOE PATENT-U.LIZ.ABT 06930581255 S.11 ~ 9 -The sulfonation behavior of the polyether ketones varies as a function of the ratio of the O-phenylone-0 units to the O-phenylene-CO unita to the CO-pheaylene-CO units and as a function of the sequence of these units along the polym.er anain. chain. Changes in the electron balance- o~
the phenylene rings- have a direct, effect on their sulfotsation behavior. However, secondary reactions are also influenced by changes in the electron balance of the phenylene rings; the combination of the reaction .para-1.0 meters--concentration. of sulfuric acid, reaction tempora-ture and. duration of reacti.on-detezzaines- to what extent O-phenylene-O units and 0-phenylor1e-CO unit$ are sul-~. -:. fonated and to what cxtenc crozslinking via 8ulfone groups or breakdown of the main chain occurs.

i5 For each polyether ketone, therefore, thexe- will be a different combination of reaction parameters which is ideal on, the one hand to obtain a high proportion of sulfonated O-phenylene-CO units and on the other hand to minimize crosalinking reactions and chain breakdown. The 20 proGeee according to the invention is disting'uished by the choice of that combination of parameters which is most appropriate to ei'lsure, in this sense, a highly favorable course of the sulfonation reaction.

it is a general rule that electiron-ri.ch aromatic struc-tures are sulfonated preferentially. Where different reaCtion sites are available for sulfonatxon, i.e. where the starting polymer has a variety of aromatic structures with different electron densities, then the selectivlty of the reaction site depends inter alia on the respective reaction parameters (Lizne, temperature, acid concentra-tion).

rn order to obtain a preferred degree of sulfonation in Q-phenylene-CO units different selectivities are de.sir-able depandi,.ng on the struature of Lha starting polymer.
Z'2ierefore, in depende .ca ori the stz~u.cture Uf the Fst=artirig pol.y7:nez:, di.f-F_eran.t Gc~r.n4ir~~tion.a of z'cract,io1-1 19 SEP '97 14:26 HOE PATENT-U.LIZ.ABT 06930581255 S.12 are particul.arly preferable.

The polyether ketones will therefore be subdivided in accordance with the electron status of their aromntic structures.
O-phenylone-d unito are richer in electrons and therefore easier to sulfonate than O-phenyl.ene-CO units, whi.laO-pheaylene-CO unitg. ia turn ara more readily sul-gonatable tihaa CO-phenylene-CO units. A measure ot the sulfonata.bility (S) of a. polyether ketone is:

8 4 ES + ER - RK
where S ffiulfonatabili.ty parameter EE - percentage proport.~on of the O-phenylene-O units EIt = percentage proportion of the O-phenylene-CO units XS KR = percentage proportion of the C4-pheziylcne-CO units on the aromatic structures in the polymer.
Therefora:

EE + ER + ICK = 100%

In selecting the pxeferred combinations of reaction parameters, account must, al.so be taken of the ratio V:
V = EK / EE

It can generally be assumed that 1. the higher the value of V, the more sevexe the reaction conditions required to obtain a high proportion of sulfonated O-phenylene-CO u.nits;
2. the lower the sulfona.tabiJ.i.ty S, the longer the time an,d/or the more sevez'2 th,e reaction conditions required.
in order to obtain the desired degree of sul.tonEition; and 3. C.he nzo,re severe the reaet:ior.x coz'tdit7.onc and the 1.onger tri.e rea:tlon times, the gx-eater tha exte-r,.t to which secondary r eaction:s occu.z.

19 SEP '97 14:27 HOE PATENT-U.LIZ.ABT 06930581255 S.13 If the polymers to be sulfonated are subdivided in accordance with the schema set out above, the fol.lowing claesification results: polymers where 9> 150% are regarded as read;Lly aulfonatable, polymers where 150% > 5> 80% are mQderately sulfonatable and polymers were S.< 80% are classed as difficult to sulfonate.
Taking these points into account, it is evideut. that certain combinations of reaction parameters are partinu-larly suitabla for prepari.ng the_ desired sulfonatioa products. Di~fereat combinations= do not lead to the, required products. The examples- in the tablee clarify this interrelationship.

Considering, for example,. a moderately sulfornatable polyether ketone of the formula (XII) (Table 1) , it is found that the proportion of 0-phenylene-CO units which are sulfonated inczeases, for a given temperature, as the reaction time inCreases. in this case it is poseib].ato set the temperature at a].evel such that the sulfonation of 0-phenylene-Co units takes place in adjusttable periods of time, and, at the aame time, any unwanted secorxdary reactions are largely exCluded. Below a certain tempera-ture threshold (60 C), however, only minimal or no sulfonation of the ether ketone units is obeerved even in the case of relatively long reaction times. The same applies to the reaction concentration ot the eulfuric acid. Thus at a sulfuric acid concentration of -q 90% by weight, no sulfonation of the O-phany].ene-CO units is obaerved even at appropriately long reaction times. With an acid caxi.centratiorx of > 90 and s 99% by weight, on the other hand, disttnct su].tonatiorl is observed even at ntioderate tentperatures within short reaction tiuties, and this degree of $ulfonation can be increased etz.ll further by increasing the reaction time while uiaintaini.ng the tempers.ture.
By an appropriate coznba.n.a.t.iorl of the reaction paramE:ters it io posini.b:Le, with the aid of the process accorda.rig to th= i=r.avention, to obtairi urlde:r rc,i.ld c.oxa.ditione -19 SEP '97 14:27 HOE PATENT-U.LIZ.ABT 06930581255 S.14 ~ 12 -polyrners whiah have a high degree of sulfonation of the ether ketone units (from 3. to 50%), with disruptive secondary reactiona being largely auppressed. By appro-priate combination of the reaction parameters it is possible to employ the process according to the invention under relatively severe conditions._to obtaxa polymers having a, high degree of aulfonatioxx, df. the- ether ketone unxts (from 1 to 100%).

In. the course of the preparation_ of tho auLfonated polymers according to the inventioa, the coacentxatioa o~
sulfuzic acid is inareased after the dipsolutioxz process, for example by adding oleum, until the concentration of sulfuric acid ia from 98 to 100% by weight or until the concentration of oleum is from 0.01 to 15% by weight of s03 , in particular until the concentration of sulfuric.
acid i.s from 98.5 to 100% by weighti. or. until the concers, txation of oleurn in from 0.01 to- 5 e by weight of SO3, a.nd preferably until the concentration of sulfuric acid is froua 98.5 to 100% by weight or until the concentration of oleum is from 0.01 to 1% by weight of S03.

During the actual su7,foiriation, the reaction temperature-ntay be higher or else lower than in the dissolution proceeg. Sulfonation is in general carried out at temperatures in the range from 10 to 100 C, in particular from 30 to 951C and, with particular preference, from 50 to 90 C. An increase in temperatuze and an increase in the Xeacti.on time both raise the degree of su].fonation of the polymer. The tempexature of the stiolution aEter adding the sulfonating agent is in parti.culax at J.eas t 300C.
Typical reaction tiutes are in the range frorn-45 minutes to 24 hours, preferably between I. and 8 hours, particularly preferably in the range from I to 4 hours.
As soon ast the desired degree of eulfonaGion is reached, the reaction is terminated &zxd, the polymer in preci,pitated, for exa.mple in an aqueous medi.um, isolated aad dried.

19 SEP '97 14:28 HOE PATENT-U.LIZ.ABT 06930581255 S.15 Investigations have shown that breakdown of the polymer main chal.n takes place only to a small extent during the sulfonation reaction. Any CO-phenylcne-CO units present in the aromatic polyether ketone employed are not sul-fonated by the process of the invention.

The advantage of. the sulfoaated G-pheaylene-CO uai.ts ovor sulfonated O-phenylene-O units in conventional polymers lies, inter alia., ia the, improved stabili.ty to hydrolysis off the S03H or S03M groups . In an aclueoue enviroameat a.nd at elevated temperatures, desu1 fonati.on oE the sulfonated polyether ketones may take place. It is- knowa, tha.t the extent of hydro].ytic desv.lfoaatiost depends oa the elec-~.
tron status of the aromatic rings. When sulfonated polymers are employed in an.aqueous medium, it ie vital that the properties of the sulfonated polymer remain aonstant. In the case of such applications, therafore, it ia advantageous to use a sulfonated polyether ketone which allowg minimal or zero desulfonation. Consequentl.y, a polymer' whose sulfonic acid groups are located to as high as possible an extent at 0-pheny7.ene-CO units ia particularly suitable in such cases. Following sulfona-tion, the sulfonic acid groups (S03H) can be converted into their salt form (SO3M) by the known methods.

The process described results in sulfonation productg which above a certain degree of aul,fonation can be dissolved in customary solvents, for examtple NMP or DMSO.
The polymer electrolyte solutions prepared in this way comprise, in a preferred embodiment, at least 1% by weight of po].yether ketones of the t ormula (II) and, as principal constituent, aprotic dipolar solvents, for example N-methylpyrrolidone (NMP) or dimethyl sulfoxide (DMSO) .
Depending on the purpose for which the polymer electro-lyte soluti.on is subsequ.ently to be used, it xnay if desired comprise a further unsulton.at.ed polymer Qr else sr.aall quazltities of a.uxifiazies.

19 SEP '97 14=28 HOE PATENT-U.LIZ.ABT 06930581255 S.16 The polymer electrolyte solutions according to the inventi,on are particularly suitable for the production of aaymmetria membranes, for exaampl.a for nano-, ultra- or microfiltration, and for the production of cohesive films having a thickness in the range from 5 m to 1 mm.

The polymer electrolyte solutions' according to the invention have an especially important role to pl.ay in the establisriment of particularly intensive. aontact between two polymer electrolyte surfaces. A porous or rough surface can ba obtained in this way, for exa=nple, aftez, contacting the solution with a precipitating agezit.
~- .
The novel polymers and polymer electrolyte solutions or polymer ff.lms compriaing these polymera are particularly suitable for use in eleatroChemical aglls, for example 3'5 fuel cells or water electrolysis cells.

Examples:
96% strength concentrated sulfuric acid was placed in a four-necked stirred apparatus fitted with. dropping funrnel and oil bath, and va~i.ous polyether ketones of the formula (I) were dissolved. oleum (containing 20% by weight of SO3) was then. added to obtain a sulfonating mi.xture having sulfuric acid concentrations of from 98.5 to 100% by weight, or oleum concentrations of trom 0.1 to 0.7% by weight of S03. The mixture was then brought to room temperature in order to ensure optimum, controlled sulfonation. After the desired degree of sulfonation had been reached, the reaction was t rminated and the product was isolated. The product was characterized by vi.sCometry, 1'3C-NMR spectroscopy and elemental analysis.

The experiments in Table 1 were carx=ied out with a hGmopaXymer of the foznluJ.a (rIl) . The experiments in Table 2 were carried out with a hornopo7.ymcAr of the formula (IV) . X'olyulers of the formula (111) havQ an S
vZZLla of 125% and ~-).re t.h.a_r,efo:-e el.aesif _ec=', ais zttor].e=r.atc:]õy.

19 SEP '97 14:28 HOE PATENT-U.LIZ.ABT 06930581255 5.17 ~ 15 -sulfonatable, while those of the formula (IV) have an S
value of 180% and are regarded, in accordance with the invention, as readily su].fonatable.

Examples which show a degree of sulfonatioa of the O-phenylene-CO units. (SEX based on one repeating urxit in mol%) of zero are to be viewod as comparative examples.
The following abbreviations are used,ia the tabl.es:

No. Experiment Number DT Dissolution temperature in C
Dt Dissolutioa time in minutes PC Polymer concentration in % by weight RX Reaction concentration. of oleum in t by weight- of RC Reaction concentration of sulfuric aaid in % by weight of H2S04 RT Reaction temperature in C (sulfonation temperature) Rt Reaction time in mi.nutea D5 Degree of sulfonation in mol% based on one repeating unit SEE Degree of aulfonat'ion of the O-phenylene-O units in mo].% baged on, one repeating unit SEK Degree of sulfonation of the 0-phenylene-CO units in mol a based on one repeating unit IV Zntrinsic viscosity in dl/g (meagured in conc. H2SO4 at 25 C) 19 SEP '97 14:29 HOE PATENT-U.LIZ.ABT 06930581255 S.18 - ~6 -Table 1:
Homopo7.ymer of the formula (11I) No. pC DT Dt= RC RT Rt DS SEE SEX IV
1 6.7 60 60 98.5 80 0 32.3 31.0 1.3 0,86 2 6.7 60 60 98.5 80 30 53..1 47.8 5"-3 0-84 3 6.7 60 60 98.5 80 60 71 52.9 8.7. 0-84 4 6.7 60 60 98.5 80 90 82.7 73_4 9.3 0.80 5 6.7 60 60 98.5 80 120 88.5 49.3 9.2. 0.80 6 6.7 60 60 98.5 80 150 94.0 83.9 10.1 0.76 7 6.7 60 60 98.5 80 210 100.6 90.0 10.6 0.~3 8 6.7 60 60 98.5 80 240 102.1 92.1 10.0 0.72 [ ..

9 6.7 60 60 98.5' 60 0 29.0 29.0 0 0.87 10 6.7 60 60 98.5 60 30 33.7 33.7 0 0.87 11 6.7 60 60 98.5 60 60 38.8 38.8 0 0.86 12 6.7 60 60 98.5 60 90 42.3 42.3 0 0.84 1,3 6.7 60 60 98.5 60 120 44-9 44.9 0 0.81 14 6.7 60 60 98.5 60 150 48.a 48.2 0 0.79 15 6.7 60 60 98.5 60 210 53-1 53.1 0 0.77 16 6.7 60 60 98.5 6o 240 55.8 54.8 1..0 0.72 17 6.7 60 60 98.5 90 0 20.5 20.5 0 0.83 18 6.7 60 60 98., 90 30 33.1 30.8 2.3 0.82 19 6.7 60 60 98.5 90 60 48.0 43.2 4.8 0.79 20 6.7 60 60 98.5 90 90 58.4 51.6 6.8 0.74 21 6.7 50 60 98.5 90 120 66.7 58.1 8.6 0.70 22 6.7 60 60 98.5 90 150 74.6 65.0 9.6 0.65 23 6.7 60 60 98.5 90 210 85.7 73.9 11.8 0.61 24 6.7 60 60 98.5 90 240 90.0 77.0 13.0 0.59 25 6.7 60 60 98.5 100 0 19.5 19.5 0 0.&0 26 6.7 60 60 98.5 100 30 43.4 39.1 4.3 0.78 27 6-7 60 60 98.5 100 60 74.3 64.7 9.6 0.74 28 6.7 60 60 98.5 100 90 87.7 72.8 14.9 0.71.

19 SEP '97 14:29 HOE PATENT-U.LIZ.ABT 06930581255 S.19 Iso. PC DT X1t RC FiT FLt 08 8&S SEX IV
29 6.7 60 60 98.5 100 120 96.5 83.0 13.5 0.68 30 6.7 60 60 98.5 1.00 150 103.2 86.7 16.5 0.63 31. 6.7 60 60 98.5 100 210 11.8 93.5 18.3 0.59 32 6.7 60 60 98.5 100 240 7,15.a 95.3 19.9 O.S5 33 6.7 68 60 90.0 80 0 37.7 . 37.7 0 0.86 34 6.7 60 60 90.0 80 30 38.2. 38.2 0 0.86 35 6.7 60 60 90.0 80 60 38.7 38.7 0 =0.83 36 6.7 60 60 90.0 80 90 39.2 39.2 0 0.82 3'7 6.7 60 60 90.0 80 120 39.7 39.7 0 0.81 38 6.7 60 60 90.0 80 150 41.6 41.6 0 0.T9-{. 39 6.7 60 60 90.0 80 210 44.3 44.3 0 0.76 40 6.7 60 60 90.0 80 240 45.7 45.7 0 0.75 41 6.7 60 60 99.0 80. 0 30.4 29.4 1.0 0.85 1 5 42 6.7 60 60 99.0 80 30 48.2 43.3 4.9 0.84 43 6.7 60 60 99.0 80 60 68.3 59.9 8.4 0.81 44 6.7 60 60 99.0 80 90 = 82.0 73.9 8.1 0.79 45 6.7 60 60 99.0 80 120 88.9 76.1 12.8 0.77 46 6.7 60 60 99.0 80 150 93.9 83.0 10.9 0.73 47 6.7 60 60 99,0 80 210 99.5 84.6 14.9 0.70 48 6.7 60 60 99.0 80 240 101.8 86.5 15.3 0.68 49 6.7 60 60 95.~i 80 0 25.4 25.4 0 0.85 50 6.7 60 60 95.2 80 30 29.4 29.4 0 0.85 51 6.7 60 60 95.2 80 60 32.8 32.8 0 0.85 52 6,7 60 60 95.2 80 90 35.4 35.4 0 0.84 53 6.7 60 60 95.2 80 120 38.2 38.2 0 0.84 54 6.7 60 60 95.2 80 150 41.0 41 0 0.80 55 6,7 60 60 95.2 90 210 45.1 46.1 0 0.78 56 6.7 60 60 95.2 80 240 48.4 48.4 0 611 19 SEP '97 14:29 HOE PATENT-U.LIZ.ABT 06930581255 5.20 Tab1e 2:
Somopalymer of the ~orinula (IV) No. PC DT Dt RC RT Rt DB 9EE SE1C IV
6.7 60 60 95 60 0 27.a 27.2 0 0.93 a 6.7 60 60 95 60 30 32.4 32.4 0 0.93-3 6.7 60 60 95 60 60 35-.7 35..7 0 0.92 4 6.7 60 60 95 60 90 39.1 39.1 0 0.90 6.7 60 60 95 60 110 42.5 42.5 0 0'.87' 6 6.7 60 60 95 60 180 49.3 49.3 0 0.86 7- 6.7 60 60 95 60 240 54.8 54.0 0.8 0.86 8 6.7 60 60 95 60 300 59.1 38.1 1.0 0.85 9 5.7 60 60 95 60 360 63.6 6a.5 1.1 0.85, 10 6.7 60 60 97 70 0 34.3 33.0 1.3 0.88 11 6.7 60 60 97 70 30 59.7 53.a 6.5 0.87 7.5 12 6.7 60 60 97 70 60 72.1 63.a 8.3 0.86 13 6.7 60 60 97 70 90 82.2 72.7 9.5 0.84 14 6.7 60 60 97 70 120 89.4 79.9 9.5 0.83 6.7 60 60 97 70 zs0 101.5 89.3 12.a 0.79 16 6.7 60 60 97 70 180 110.2 96.a 14.0 0.75 17 6.7 60 60 97 70 240 116.3 100 16.3 0.74 18 6.7 60 60 97 70 300 12a.7 100 23.7 0.73 19 6.7 60 60 981 90 0 31.2 a9.1 1.1 0.84 20 6.7 60 60 98 90 30 103.9 89.5 14.4 0.80 21 6.7 60 60 98 90 60 119.8 97.8 22.0 0.78 _F'% 90 ].28.5 100 28.5 0.7a 2 5 22 6.7 60 60 98 90 (, .
23 .6.7' 60 60 98 90 120 140.2 100 40.2 0.70 24 6.7 60 60 98 90 150 145.2 100 45.2 0.68 6.7 60 60 98 90 2a5 148.7 100 48.7 0.65 26 6.7 60 60 98 60 0 32.5 31.7 0.8 0.87 3 Q 27 6.7 60 60 98 60 30 55.4 49.9 5.5 0.87 19 SEP '97 14:30 HOE PATENT-U.LIZ.ABT 06930581255 S. 21 -i9-NO. PC DT Dt RC RT Rt D$ 3x:E 9ER IV
28 6.7 60 60 98 60 60 68.1 60.5 7.6 0.86 29 6.7 60 60 98 60 90 79.5 72.6 6.9 0.84 30 6.7 60 60 98 60 120 89.2 80.8 8.4 0.83 31 6.7 60 60 98 60 150 96-.5 86.5 10.0 0.78 32 6.7 60 60 98 60 7.80 102,.1 93.9 8_2 0.75 33 6.7 60 60 98 60 240 110.6 96.5 14.1 0.72.
34 6.7 60 60 98 60 300 121.8 100 21.8 0.70 35 6.7 60 60 95 90 0 35.5 35.5 0 0.25 I.0 36 6.7 60 60 95 90 30 58.3 50.1 8.1 0.85' 37 6.7 60 60 95 90 60 82.3 73.4 8.9 0.84 t,..i 38 6.7 60 60 95 90 90 95.7 86.5 9.2 0.81 39 6.7 60 60 95 90 120 105.1 97.6 7.5 0.79 40 6.7 60 60 95 90 150 115.3 98.5 16.8 0.76 1S 41 6.7 60 60 95 90 180 120.7 100 20.7 0_76 42 6.7 60 60 95 90 240 132.4 100 32.4 0_73 43 5.7 60 60 95 90 300 135.8 100 35-8 0.72 19 SEP '97 14=30 HOE PATENT-U.LIZ.ABT 06930581255 5.22 Table 3:
Iiomopolymers of the forzaula (V) Yto. PC DT Dt R]C RT Rt SSS BER DS YV
1 6.7 50 60 0.4 60 0 0 2.3 2.3 0.92 2 6.7 50 60 0.4 60 30 0 8.7 8.7 0.91 3 6.7 50 60 0.4 60 60 0'. 14.0 14.0 0.88 4 6.7 50 60 0.4 60 90 0 17.2 17.2 0.84 6_7 50 60 0.4 60 120 0 20.2 20.2 0.13S
6 6.7 50 60 0.4 60 150 0 23.5 23.5 0.81 7 6.7 50 60 0.7 50 0 0 3.7 3.7 3..00 8 6.7 50 60 0_7 50 30 0 7.0 7.0 0.97 9 6.7 50 60 0.7 50 60 0 11..1 11.1 0_92 10 6.7 so 60 0.7 50 120 0 17.8 17.8 0.90 11. 6.7 50 60 0.7 50 180 0 22.1 22.1 0.88 1 5 12 6.7 50 60 0.7 50 240 a 26.0 a6.0 0.85 13 5.7 50 60 0.7 50 360 0 31.3 31.5 0.e2 14 6.7 50 60 0.7 50 460 0 38.2 38.2 0.75 6.7 50 60 0.7 50 525 0 41.0 41.0 0.73 16 6.7 50 60 0.7 70 0 0 2.7 2.7 0.95 17 6.7 50 60 0.7 70 60 0 40.2 40.2 0.78 18 6.7 50 60 0.7 70 120 0 62.3 62.3 0.72 19 6.7 50 60 0.7., 70 180 0 75.2. 75.2 0.61 20 6.7 50 60 0.7 70 240 0 84.2 84.2 0.59 21 6.7 50 60 0.7 70 320 0 92.0 92.0 0-96 22 5.7 50 so 0.1 50 0 0 1.2 1.2 1.03 23 6.7 50 60 0.1 50 60 0 2.1 2.1 0.98 24 6.7 50 60 0.1 50 120 0 4.1 4.1 0.93 25 6.7 50 60 0.1 50 180 0 5.7 5.7 0.90 19 SEP '97 14:30 HOE PATENT-U.LIZ.ABT 06930581255 S.23 - 21.
-No. pC DT 1]t RR RT Rt 8EE SE7C DS IV
26 6.7 50 60 0.1 50 240 0 7.3 7.3 0.88 27 6.7 50 60 0.3. 50 300 0 B.I. 9.1 0.89 28 6.7 50 60 0.1 50 435 a 12.9 12.9 0.85 29 6.7 50 50 0.1 70 0 0 2.5 2.5 0.90 30 6.7 50 60 0.1 70 30 0 14.3 14.9 0.88 31 6.7 50 60 0.1 70 60 0 17.7 17_7 0.86 32 6.7 30 60 0.1 70 120 0 21.2. 2X.2 0=,83 33 6.7 50 60 0..1 70 1.80 0 23.4- 23.4. 0.78 34 6.7 50 60. 0.1 70 330 0 31.9 32.9 0.73 35 5_7 so 60 0.1 70 390 0 35.2 35.Z 0.71 i. ,

Claims

CLAIMS:

1. A sulfonated aromatic polyether ketone, comprising units of the general formula (II):

[[Ar-O-]p-Ar-[[CO-Ar'-]x-O-Ar]m-[CO-Ar'-]y-[O-Ar-]n-CO-]

(II) wherein:

from 1% to 100% of the O-phenylene-CO units are substituted with an SO3M group, and wherein the sulfonated and unsulfonated O-phenylene-CO units and sulfonated and unsulfonated O-phenylene-O units are in any sequence with respect to one another;

Ar is a phenylene ring with para, meta or para and meta bonds;

Ar' is a phenylene, naphthylene, biphenylylene, anthrylene or another divalent aromatic unit;

x, n and m independently of one another are 0 or 1;

y is 0, 1, 2 or 3;

p is 1, 2, 3 or 4; and M, taking into account the ionic valencies, is selected from the group consisting of H, NR4+, a metal and a combination thereof, wherein R is H or C1-C4-alkyl.

2. A sulfonated aromatic polyether ketone as claimed in claim 1, wherein M when a metal is an alkali metal, an alkaline earth metal or a metal from subgroup 8.

3. A sulfonated aromatic polyether ketone as claimed in claim 1 or 2, which comprises units of the formula (III):

4. A sulfonated aromatic polyether ketone as claimed in claim 1 or 2, which comprises units of the formula (IV):

5. A sulfonated aromatic polyether ketone as claimed in claim 1 or 2, which comprises units of the formula (V):

6. A sulfonated aromatic polyether ketone as claimed in claim 1 or 2, which comprises at least two units of the formula (II) as defined in claim 1 or 2, formula (III), formula (IV), formula (V) or formula (VI):

7. A process for the preparation of a sulfonated polyether ketone in which from 1% to 100% of the O-phenylene-CO units are substituted with an SO3M group, wherein M is as defined in claim 1, by dissolving a polyether ketone of the general formula (I):

[[Ar-O-]q-Ar-[[CO-Ar'-]r-O-Ar]s-[CO-Ar'-]t-[O-Ar-]u-CO-]~(I) wherein:

Ar and Ar' are as defined in claim 1;

r, u and s independently of one another are 0 or 1;

t is 0, 1, 2 or 3; and q is 1, 2, 3 or 4 in 94 to 97% strength by weight sulfuric acid, adding a sulfonating agent to the solution obtained at an appropriate temperature, and working up the reaction mixture thus obtained as soon as the desired degree of sulfonation of the O-phenylene-CO units is reached, and, optionally, converting the sulfonic acid groups into their salt form.

8. The process as claimed in claim 7, wherein the dissolution temperature is in the range from 10 to 80°C.

9. The process as claimed in claim 7 or 8, wherein the sulfonation temperature is in the range from 10 to 100°C.

10. The process as claimed in any one of claims 7 to 9, wherein after adding the sulfonating agent the temperature of the solution is at least 30°C.

11. The process as claimed in any one of claims 7 to 10, wherein the sulfonating agent used is sulfuric acid, fuming sulfuric acid, oleum, chlorosulfonic acid, sulfur trioxide or a mixture thereof.

12. The process as claimed in any one of claims 7 to 11, wherein oleum is added to the polyether ketone dissovled in sulfuric acid until the concentration of sulfuric acid is from 98 to 100% by weight or the concentration of oleum is from 0.01 to 15% by weight of S03.

13. The process as claimed in any one of claims 7 to 12, wherein the radical Ar' is phenylene.

14. The process as claimed in any one of claims 7 to 12, wherein an aromatic polyether ketone is employed which is a copolymer synthesized from at least two different units of the formulae (II), (III), (IV), (V) and (VI) as defined in claim 6.

15. The process as claimed in any one of claims 7 to 12, wherein a mixture of different aromatic polyether ketones is employed in which at least one such ketone is synthesized from units of the formulae (III), (IV), (V) or (VI) as defined in claim 6.

16. The process as claimed in any one of claims 7 to 15, wherein an aromatic polyether ketone is employed wherein the nonsulfonatable units are CO-phenylene-CO units.

17. The process as claimed in claim 7, wherein for the polyether ketone of the general formula (I), the polyether ketone of the formula (III) as defined in claim 3, is dissolved in 95 to 97% strength by weight sulfuric acid at not more than 80°C and is sulfonated in 95 to 99% strength by weight sulfuric acid at a temperature from 10 to 80°C.

18. The process as claimed in claim 7, wherein for the polyether ketone of the general formula (I), the polyether ketone of the formula (IV) as defined in claim 4, is dissolved in 95 to 97% strength by weight sulfuric acid at not more than 80°C and is sulfonated in 95 to 97% strength by weight sufuric acid at a temperature from 30 to 90°C.

19. The process as claimed in claim 7, wherein for the polyether ketone of the general formula (I), the polyether ketone of the formula (V) as defined in claim 5, is dissolved in 95 to 97% strength by weight sulfuric acid at not more than 80°C and is sulfonated at a temperature from 50 to 100°C.

20. A process for the preparation of a sulfonated polyether ketone by dissolving the polyether ketone of the general formula (I) as defined in claim 7 in 94 to 97%
strength by weight sulfuric acid, sulfonating the polyether ketone in sulfuric acid, fuming sulfuric acid, oleum, chlorosulfonic acid or a mixture thereof and working up the reaction mixture as soon as the desired degree of sulfonation is reached, wherein from 1 to 100% of O-phenylene-CO units are substituted with an SO3M group wherein M is as defined in claim 1 or 2.

21. A polymer electrolyte solution comprising a sulfonated aromatic polyether ketone as claimed in any one of claims 1 to 6.

22. A polymer electrolyte solution as claimed in claim 21, which comprises at least 1% by weight of polyether ketones of the formulae (II), (III), (IV), (V), (VI) or a combination thereof, as defined in claim 6.

23. A polymer electrolyte solution as claimed in claim 21, which comprises as principal constituent one or more aprotic dipolar solvents.

24. A polymer electrolyte solution as claimed in claim 21, which comprises a further sulfonated or unsulfonated polymer and, optionally, a small quantity of an auxiliary.

25. Use of a polymer electrolyte solution as claimed in any one of claims 21 to 24, for the production of an asymmetric membrane.

26. Use of a polymer electrolyte solution as claimed in any one of claims 21 to 24, for the production of a cohesive film.

27. Use of a polymer electrolyte solution as claimed in any one of claims 21 to 24, for establilshing an intensive contact between two polymer electrolyte surfaces.

28. Use of a polymer electrolyte solution as claimed in any one of claims 21 to 24, for obtaining a porous or rough surface after contacting the solution with a precipitating agent.

29. Use of a sulfonated aromatic polyether ketone as claimed in any one of claims 1 to 6, for preparing a polymer electrolyte solution or for producing a polymer film.

30. Use of a sulfonated aromatic polyether ketone as claimed in any one of claims 1 to 6, or a polymer film as claimed in claim 29, in an electrochemical cell.

31. The use as claimed in claim 30, wherein the electrochemical cell is a fuel cell or an electrolyzer.

32. A film having a thickness of from 5 µm to 1 mm, which comprises a sulfonated aromatic polyether ketone as claimed in any one of claims 1 to 6.