CA2299621A1 - Hexafluoropropene-based fluoro-sulphonated elastomers with low tg, not containing either tetrafluoroethylene or a siloxane group - Google Patents

Abstract

The present invention describes the synthesis of new fluorinated elastomers having very low glass transition temperatures, good resistance to bases, to petroleum and to fuels and good processing properties. These elastomers contain, for example, from 10 to 32% of hexafluoropropene (HFP), from 19 to 79% of perfluoro (4-methyl-3,6-dioxaoct-7-ene) sulfonyl fluoride (PFSO2F) and from 0 to 71% vinylidene fluoride (VDF). In this specific case, they are prepared by radical copolymerization of HFP and PFSO2F or by radical terpolymerization of HFP, PFSO2F and VDF in the presence of different organic initiators such as, for example, peroxides, peresters or diazo.

Description

TITLE
Low Tg fluorosulfonated elastomers based on hexafluoropropene fluoride and containing neither tetrafluoroethylene chu nor siloxane group FIELD OF THE INVENTION
The present invention describes the synthesis of new fluorinated elastomers with very low glass transition temperatures, good resistance to bases, petroleum and fuels and good processing properties.
These elastomers contain, for example, from 10 to 32% of hexafluoropropene (HFP), from l0 19 to 79% perfluoro (4-methyl-3,6-dioxaoct-7-ene) sulfonyl fluoride (PFSOZF) and 0 to 71% vinylidene fluoride (VDF). In this case, they are prepared by radical copolymerization of HFP and PFSOZF or by terpolymerization radical HFP, PFSOZF and VDF in the presence of different organic initiators as for example peroxides, peresters or diazo.
PRIOR ART
Fluorinated elastomers have a unique combination of properties (thermal resistance, to oxidation, to UV, to aging, to agents chemical corrosive and to fuels; low surface tension, constant dielectric and absorption ao d'eau), which enabled them to find “high teak” applications in many fields: seals (space, aeronautics), semiconductors (micro-electronics), hoses, pipes, pump bodies and diaphragms (industries chemical, automobiles and oil).

-2-However, VDF-based elastomers are few. Even if the Kel F ~ (VDF / CTFE) and FLUOREL ~, DAI-EL ~, FKM ~, TECHNOFLON ~ or VITON ~ (A: VDF / HFP; B: VDF / HFP / TFE) have good resistance chemical and thermal, their Tg is not low enough. The weakest value found s in the literature is that of VITON ~ B, ie a Tg of -26 ° C.
This last value is nevertheless surprising since the manufacturer announces a Tg varying from -5 to -15 ° C for VITONfl B. Also, to compete with these elastomers, Ausimont proposed a copolymer VDF / HCF = CFCF3 (Technoflon ~), flame resistant and oxidation but having no Tg below -26 ° C and whose comonomer is difficult to access.
io If the copolymers of HFP with TFE are thermoplastics, it is necessary to introduce another fluorinated monomer such as, for example, ethers trifluorovinyls providing the elastomeric character. So, copolymers made of these fluorinated ethers but containing no HFP were prepared by the Company Du Pont i5 who suggested a new generation of elastomers based on perfluoroalkyl vinyl ether (PAVE) resistant to low temperatures. For example, copolymers such as the TFE
/ perfluoromethyl vinyl ether (PMVE) (marketed under the name of Kalrez ~
whose T ~ do not drop below -15 ° C) and the TFE / PAVE copolymers (US 4,948,853) have been produced, as well as tetpolymers that have even higher Tg's bass ao TFE / ethylene / PMVE (Tg = -17 ° C) or TFE / VDF / PAVE (EP 0 131 308) and above all TFE / VDF / PMVE (Viton GLT ~ Tg = -33 ° C). In addition, the elastomers to TFE base /
PAVE / VDF, used as O-rings, have very good resistance to polar solvents (EP 0 618 241, Ausimont and Japanese patent -A-3066714 Chem.
Abstr., 115: 73436z). Terpolymerization of TFE with PMVE and

-3-FzC = CF [OCFZCF (CF3)] nOC3F, (Uschold, Polym. J., 17 (1985) 253) led to elastomers whose Tg (from -9 to -76 ° C) depend on the value of number n of patterns HFP oxide and the percentage of the two oxygenated comonomers.
s Finally, the DuPont company produces Nafion membranes by copolymerization of TFE with FZC = CFOCFZCF (CF3) OCZF4SOzF (PFSOzF).
In addition, the company Asahi Glass uses this same sulfonated monomer for the Flemion membrane manufacturing ~. Other monomers with the same functionality lo FZC = CFOCFZCF (CF3) OCjF6SO2F (Aciplex ~, Asahi Chemical) or CF, = CFOCzF4SOzF
or of carboxylate functionality FZC = CFOCFZ [CF (CF3) O] XCZF ~ COZCH3 (x = 1 Nafion ~, Du Pont or Aciplex ~ and x = 0 Flemion ~) are also used.
This state therefore encouraged us to use HFP (cheaper and more alkene easy to 15 implement more of the TFE) and consider copolymerization original of HFP with functional perfluoroalkyl vinyl ethers (PAVE) and / or perfluoroalkoxy alkyl vinyl functional ethers and in particular PFSOZF.
Indeed, this monomer has the advantage of being functional and promotes sites of crosslinking, so to prepare original elastomers with good resistance to low zo temperatures and good processing properties ("processability or help processing ”). Furthermore, the use of HFP gives the polymers formed a character increased elastomer and improves their thermostability and resistance to chemical agents, to petroleum and oxidation.
zs Concurrent work approaching the studs of the invention

-4-Beside the patents cited above, showing terpolymerization or pentapolymerization, two publications and eleven patents describe the copolymerization of HPF with other fluorinated olefins but use PAVEs (and mainly from perfluoromethyl vinyl ether or 2-bromoperfluoroethyl perfluorovinyl ether) different s from PFSOZF.
EP 0 525 685 describes the synthesis of HFP / PMVE / VDF terpolymers (where the term PMVE designates perfluoromethyl vinyl ether) leading to T ~ elastomers equal to -27 ° C (lowest value) unlike that of VDF / HFP copolymers lo (Tg - -23 ° C). WO 9220743 describes the synthesis of terpolymers VDF / I ~ P / FZC = CFO (CFz) nCF3 (where n = 0-5) obtained in the presence of transfer agent 1,4-düodoperfluorobutane then are crosslinked with peroxides. They are mainly of Tetrapolymers based on TFE, VDF, HFP and PAVE which have been produced.
Through example, DE 2,457,102 describes the preparation of HFP / PMVE / TFE tetrapolymers /
i5 VDF by emulsion copolymerization. EP 0 525 687 relates the synthesis of polymers HFP / PAVE / VDF / TFE with good chemical resistance and ease of stake in use (molding). Similar properties have been observed for tetrapolymers based on HFP / PAVE / VDF and olefins having from 2 to 4 carbon atoms mentioned in EP 0 570 762. In addition, CA 2,068,754 mentions pentapolymers zo HFP / VDF / TFE / PMVE / ethylene whose Tg range from -9 to -18 ° C and down to -28 ° C
when the monomer FzC = CFOCZF4Br also participates in this hexapolymerization. Of even crosslinkable elastomers based on HFP, VDF, TFE and the monomer brominated above, have been described in EP 0 410 351 and in CA 2,182,328 or in the articles by Apotheker et al., Rubber Chem. Technology, 55 (1982) 1004 and of Arcella and as coll., Kautsch. Gummi Kunstst., 44 (1991) 833.

-5-Addition of unconjugated diene HIC = CHC ~ F $ CH = CHZ in the polymerizations helped to crosslink these elastomers, as indicated in DE 4,137,967 and EP 0 769 521.
Furthermore, EP 0 525 685 describes the synthesis of VDF / HF'P / PMVE terpolymers (where the terms HFP and PMVE respectively denote hexafluoropropene and perfluoromethyl vinyl ether) leading to elastomers of Tg equal to -27 ° C (value la lower).
io Finally, polymerizations based on HFP, PMVE and other fluorinated alkenes were carried out in supercritical COZ medium (US 5,674,957).
DETAILED DESCRIPTION OF THE INVENTION
is The present invention describes the synthesis of elastomeric copolymers fluorinated original, based on hexafluoropropene (HF'P) and containing a perfluoroalicyl vinyl ether functional and / or a functional perfluoroalkoxyalkyl vinyl ether and eventually other fluorinated alkenes. The originality of the present invention resides in facts following:
zo 1 °) The synthesis of fluorinated elastomers based on perfluoroalkyl functional vinyl ethers and / or perfluoroalkoxy vinyl functional ethers and possibly others alkenes fluorinated, is carried out with HFP instead of tetrafluoroethylene, the latter being widely used for the manufacture of fluorinated elastomers;

-6-2 °) The synthesis of fluorinated elastomers which is discussed in the present invention does does not require the use of monomers carrying siloxane groups, these latter generally contributing to a decrease in T ~;
3) The fluorinated elastomers obtained by the present invention are of composition s minority in HFP and majority in perfluoroalkyl vinyl ether (PAVE) functional or perfluoroalkoxyalkyl vinyl ether (PAAVE) functional for copolymers and of minority composition in HFP and majority in VDF or perfluoroalkyl vinyl ether functional or perfluoroalkoxyalkyl vinyl ether functional according to reports molars initials of these two fluorinated monomers.
l0 4 °) The fluorinated elastomers synthesized by said invention have very low Tg, these elastomers can thus find applications in the field of plastics ("Aid processing" or implementing agents), or other industries of point (aerospace, electronics or automotive, petroleum, transport of fluids very cold such as liquid nitrogen, oxygen and hydrogen). In addition, seals 15 high thermal resistance can be prepared from these elastomers.
The present invention relates to the synthesis of fluorinated elastomers based on of HFP, as well as their field of applications.
ao The field of the present invention extends to all types of processes generally used: emulsion, bulk, suspension polymerization and in solution. All can be used. Solution polymerization has however been preferentially used.

- '7 _ The various fluorinated alkenes used have at most four atoms of carbon and have the structure R, RzC = CR3R4 where the substituents R, ~ are such that at least one of them is fluorinated or perfluorinated. This therefore includes: vinyl fluoride (VF), the vinylidene fluoride (VDF), trifluoroethylene, chlorotrifluoroethylene (CTFE), the bromotrifluoroethylene, 1-hydropentafluoropropylene, hexafluoroisobutylene, 3,3,3-trifluoropropene and generally all vinyl compounds fluorinated or perfluorinated. In addition, perfluorovinyl ethers also play the role of comonomers. Among them, mention may be made of perfluoroalkyl vinyl ethers (PAVE) whose alkyl group has from one to three carbon atoms: for example, the 1 o perfluoromethyl vinyl ether (PMVE), perfluoroethyl vinyl ether (PEVE) and the perfluoropropyl vinyl ether (PPVE). These monomers can also be perfluoroalkoxy alkyl vinyl ethers (PAAVE), described in US 3,291,843 and in the Prog. Polym. Sci., M. Yamabe et al. flight. 12 (1986) 229 and AL
Logothetis, vol.
14 (1989) 251, such as perfluoro (2-n-propoxy) -propylvinyl ether, perfluoro- (2-methoxy) -propyl-vinyl ether; perfluoro (3-methoxy) propyl vinyl ether, perfluoro- (2-methoxy) -ethylvinyl ether; perfluoro- (3,6,9-trioxa-5,8-dimethyl) dodeca-1-ene, the perfluoro- (5-methyl-3,6-dioxo) -1-nonene. In addition, monomers perfluoroalkoxyalkyl vinyl ethers with carboxylic ends or sulfonyl fluoride ends (such as perfluoro (4-methyl-3,6-dioxaoct-7-en) sulfonyl fluoride) may also to be used ao for the synthesis of fluorinated elastomers described in the present invention.
Mixtures PAVE and PAAVE may be present in the copolymers.
More particularly, perfluoro (4-methyl-3,6-dioxaoct-7-ene) fluoride sulfonyl was used as a comonomer.

_g_ The solvents used to carry out the solution polymerization are the following - The esters of formula R-COO-R 'where R and R' are hydrogen substituents or alkyls can contain from 1 to S carbon atoms, but also groups hydroxy s OH or ester groups OR "where R" is an alkyl containing from 1 to 5 atoms of carbon. More particularly, R = H or CH3 and R '= CH3, CZH ;, iC3H ,, t-C4H9.
- Fluorinated solvents of the type: CICFzCFCI2, C6F ", n-C4F, o, perfluoro-2-butyltetrahydrofuran (FC 75).
- acetone, 1,2-dichloroethane, isopropanol, tert-butanol, acetonitrile or io butyronitrile.
The solvents preferably used are methyl acetate and acetonitrile in variable quantities.
The reaction temperature range can be determined by the temperature 15 decomposition of the initiator and varies from 20 to 200 ° C. The temperatures preferably used are between 55 and 80 ° C.
In the process according to the invention, the polymerization can be initiated at the intervention of the usual initiators of radical polymerization. Of examples zo representative of such initiators are the azo (such as AIBI ~, dialkyl peroxydicarbonates, acetylcyclohexanesulfonyl peroxide, peroxide dibenzoyl, dicumyl peroxide, t-alkyl perbenzoates and t-alkyl peroxypivalates. However, preference is given to peroxydicarbonates dialkyl, such as diethyl and di-isopropyl peroxydicarbonates and to t-alkyl peroxypivalates such as t-butyl and t- peroxypivalates amyle and more particularly still, to t-alkyl peroxypivalates.
For the emulsion polymerization process, we used a large range of co-solvents, used in various proportions in the mixture with the water. Of even, various surfactants have been used.
One of the polymerization processes used can also be by microemulsion as described in EP 0 250 767 or by dispersion, as indicated in US
4,789,717;
EP 0 196 904; EP 0 280 312 and EP 0 360 292.
The reaction pressures vary between 2 and 120 bars depending on the conditions experimental.
i5 Chain transfer agents can generally be used to regulate and mainly decrease the molecular weights of the copolymers. Among those, mention may be made of telogens containing from 1 to 10 carbon atoms and having of bromine or terminal iodine atoms such as, for example, compounds of RFX type (where RF is a perfluorinated group RF = C "FZn + ,, n = 1-10, X denoting a atom of zo bromine or iodine) or alcohols, ethers, esters. A list of various agents of transfer used in the telomerization of fluorinated monomers is indicated in the review "Telomerization reactions of Fluoroalkanes", B. Améduri and B. Boutevin in the book "Topics in Current Chemistry" (Ed. RD Chambers), vol. 192 (1997) p. 165, Springer Verlag 1997.

The elastomers of the present invention can be crosslinked using of systems based on peroxides and triallyl (iso) cyanurate when such copolymers contain iodine and / or bromine atoms in the terminal position of the macromolecule.
Peroxide systems are well known, such as those described in EP 0 136 596.
s The vulcanization of these elastomers can also be carried out by ionic methods such as those described in US 3,876,654, US 4,259,463, EP 0 335 705 or in the Prog. Polym. Sci., 14 (1989) 251.
The whole range of relative percentages of the various synthesizable copolymers 1 o from the fluorinated monomers used, leading to the formation of homopolymers, fluorinated copolymers and terpolymers has been studied.
The products were analyzed by NMR of 'H and' 9F. This method analysis made it possible to know unambiguously the percentages of comonomers i5 introduced into products. For example, we have perfectly established from microstuctures characterized in the literature (Polymer 28 (1987) 224 and J.
Fluorite Chem., 78 (1996) 145) the relationships between the characteristic signals of copolymers HFP / PFSOZF (see Table 1) and HFP / PFSOZF / VDF terpolymers (Table 2) in 9N NMR and product structure.
zo The copolymers of such compositions can find applications in preparation of O-rings, pump casings, diaphragms having a very good resistance to fuels, petrol, t-butyl methyl ether, alcohols and oil motor, combined with good elastomeric properties, in particular a very good resistance to low temperatures. These copolymers also have the advantage of being crosslinkable in the presence of conventionally used agents.
These fluorinated elastomers were characterized by NMR spectroscopy of '9F
s (acetone or deuterated DMF) and the chemical shifts of the different groupings fluorides were mentioned in Tables 1 and 2. This analysis highlights evidence of HFP / PFSOZF, VDF / PFSOZF and HFP / VDF diades as well as head sequences tail and head-head of the VDF unit blocks (at -91 and -113, -116 ppm respectively).
io The following examples are given in order to illustrate implementations preferential of the invention, and must in no case be considered as limiting the scope of said invention.
Example 1 - Reactions in sealed tubes: HFP / PFSOzF copolymerization (% mol 15 initials 80/20) A very thick, borosilicate Carius tube (length, 150 mm;
inner diameter, 16 mm; thickness, 2.0 mm; for a total volume of 14 cm3) containing 0.1158 g (0.50 mmol) 75% t-butyl peroxypivalate, 2.21 g (4.96 mmol) of perfluoro (4-methyl-3,6-dioaoct-7-ene) sulfonyl fluoride (PFSOzF) and 2.25 g ao (0.030 mmol) of methyl acetate is connected to a vacuum ramp system and purged three times with helium by primary vacuum cycles (100 mm Hg) / Helium. Then, after five at least freeze / thaw cycles to remove dissolved oxygen in this solution, 3.0 g (0.020 mol) of hexafluoropropene (HFP) are trapped in the frozen tube in a bath of liquid nitrogen and acetone and the mass introduced is determined by double weighing. The tube still immersed in the cold bath is sealed and then placed in the cavity of a oven stirred at 75 ° C for 6 hours.
After copolymerization, the tube is frozen in liquid nitrogen and then opened.
1.80 g of unreacted gas was trapped. This destroys the rate of conversion mass of HPF according to the expression (m ~ P - 1.80) / m ~ = 40%
where mL ~ P represents the mass of HFP initially introduced.
lo Then, the yellowish liquid obtained is added dropwise to 35 mL
of strongly agitated cold pentane. After being left for 1 hour at 0-5 ° C, the mixture is poured into a separatory funnel. Clear, colorless supernatant is removed while the yellow heavy phase is dried at 70 ° C under 1 mm of Hg for 2 hours. 1.67 g of very viscous, clear liquid was obtained.
The composition of the copolymer (i.e. the molar percentages of the two or three comonomers in the copolymer) was determined by NMR of the '9F
(200 or 250 MHz) at room temperature, the deuterated acetone or DMF being the reference solvents.
For example, the different signals from the NMR spectrum of '9F and their attributions are indicated in Table 1. We can be sure of the total reactivity of sulfonated monomer by the absence of the characteristic signal centered at -137.5 ppm assigned to one of its ethylenic fluorine atoms. Based on signal integrations a5 corresponding to each comonomer, the respective HFP molar percentages / PFSOzF

in the copolymer are 32 / 68. The resin-like copolymer colorless. T ~ _ -48 ° C (Table 3).
Table 1: 9F NMR characterization of HFP / PFSOzF copolymers.
CHEMICAL MOVEMENT STRUCTURE (ppm) -S02F +45 -PFSOzF-CFzCF (CF,) - PFSOzF- -71 -75 -OCFZCF (CF3) OCFZCFzSO2F -77 -80 -OCFzCF (CF3) OCFzCF2SOzF -112 -CFzCF (CF,) - CFzCF (O-RF-SOZF) - -113 -CFZCF (ORFSO2F) -CFZCF (ORFSOzF) - -117 -PFSOZF -CFzCF (CF3) -PFSOzF- -118 -CFZCF (CF3) -CF, CF (ORFSOzF) - -122 -CF (CF3) CFz CFZCF (ORFSOzF) - -125 -OCFzCF (CF,) OCZF, SOzF -144 -PFSOzF-CFzCF (CF3) -PFSOZF- -175 -185 s Example 2: Autoclave reaction: HFP / VDF / PFSOZF terpolymerization (23 18) In a 300 mL Hastelloy reactor (HC 276), equipped with a valve gas introduction, release valve, pressure gauge, disc a break in HC 276 and with magnetic stirring at 700 revolutions / min., 48.5 are introduced g (0.11 io mol) of PFSOZF; 1.10 g (4.7 mmol) of 75% t-butyl peroxypivalate and 148.3 g methyl acetate. The reactor is closed and its tightness is checked. The cycle next is carried out 3 times: the reactor is placed under vacuum, then introduced nitrogen at 10-15 bars. These cycles allow degassing of the solution. We then perform a vacuum of 20 mm Hg in the reactor. The reactor is then placed in an acetone bath.
nitrogen is liquid in order to obtain an interior temperature of the reactor close to -80 ° C. We then successively introduces 21.0 g of HFP (0.14 mol) then 23.0 g of fluoride of vinylidene (VDF) (0.36 mol) by double weighing the reactor. Then this reactor is square in an oil bath gradually heated to a temperature of 77 ° C which is maintained for 3 hours. The maximum reaction pressure reached is 13 bars. The pressure drop observed at reaction temperature after 6 hours is

7 bars.
After reaction, the reactor is placed in an ice bath for 30 minutes and then the degassing shows a loss of 2.3 g of unreacted gas, which corresponds at a rate s conversion of the gaseous monomers by approximately 95%. The reaction crude is then treated as before, precipitating in cold pentane, then dried. The mass of copolymer recovered is 68.2 g. The terpolymer obtained is a liquid orange viscous (mass yield = 74%). Fluorine NMR characterization (Board 2) shows the absence of trace of the sulfonated monomer and made it possible to know the io percentages of the three comonomers in the teipolymer equal to 10% of HFP, 71% of VDF and 19% of sulfonated monomer (Table 4).

Table 2: 9F NMR characterization of the VDF / HFP / PFSOZF terpolymers.
CHEMICAL MOVEMENT STRUCTURE (ppm) -SO ~ F +45 -CHzCF2-CFZCF (CF) -CFZCHz- -71 -CHzCF2-CFzCF (CF3) -CHZCFz- -75 -OCFzCF (CF,) OCF ~ CFZSOzF -77 -80 tBuO-CF ~ CH ~ - -83 -CHZCFz CHzCF2-CHZCFz -91 - CHZCF, -CH2CF2- -92 -CFzCF (RF) -CH ~ CFz CH, CFZ-CF2CF (RF) - -93 -CHZCF, -CHzCF2-CFzCHz- -95 -CFZCF (ORFSO2F) -CHzCF, -CFzCF (ORFSOZF) - -108 - CHzCFz-CH2CF2-CFZCF (RF) - -110 -OCFZCF (CF3) OCF, CFzSO2F -112 -CHZCFz CHzCF2-CFzCH2- -113 -CHzCF2-CFzCHz-CH2CF2- -116 -CHZCFZ-CFzCF (CF3) -CHzCFz -118 -CHZCFz CF, CF (ORFSOzF) -CHzCF, - -122 -CH2CFz CFZCF (ORFSO_F) -CHzCF2- -125 -CHzCF2-CFzCF (ORFSO ~ F) -CFzCHZ -127 -OCF ~ CF (CF3) OC ~ F, SO2F -144 -CHZCFz-CFZCF (CF,) - CFzCH2- -183 -CH2CFz-CFzCF (CF,) - CHzCF2- -184 Other HFP / PFSOZF copolymerizations and terpolymerizations HFP / VDF / PFSOZF (experimental details and results) are summarized in the Tables 3 s and 4.
The advantages related to the present invention are mainly the following:
1 °) The synthesis process is carried out in operating mode in cuvée (“batch”);
2) The process in question in the present invention takes place in solution and io uses conventional organic solvents, readily available in the trade ;

3 °) The method of said invention consists of a polymerization radical in the presence conventional initiators, readily available commercially;
4 °) Tetrafluoroethylene (TFE) is not used in the present invention;
5 °) The perfluorinated olefin which enters into the composition of the elastomers fluorinated preparations s by said invention is hexafluoropropene; this is significantly less expensive and much less dangerous than TFE and gives the elastomers obtained a better thermostability and good resistance to oxidation, to chemical agents, with solvents polar and petroleum;
6 °) The fluorinated elastomers in question in said invention can be prepared io from the monomer PFSOzF, the copolymerization of which with HFP and the terpolymerization with HFP and VDF has never been the subject of work described in the literature. In addition, this sulfonated monomer through its fluoride function of sulfonyl, makes it possible to create crosslinking sites in these elastomers;
7 °) The fluorinated elastomers synthesized by the said invention also contain fluoride 1 s of vinylidene, significantly cheaper and less dangerous than TFE;
this monomer allows the glass transition temperature (TJ;

8 °) The fluorinated elastomers obtained by this process have very low temperatures glass transition, varying from -36 to -48 ° C.
zo Although the present invention has been described using implementations specific, it is understood that several variations and modifications may piggyback on said implementations, and the present application aims to cover such modifications, uses or adaptations of the present invention according, in general, to principles of the invention and including any variation of this description which will become known or 2 s conventional in the field of activity in which the present invention, and which can be applied to the essential elements mentioned above, in agreement with the scope of the following claims.

Claims (15)

1. Sulfonated fluorinated elastomers based on hexafluoropropene, not comprising or of tetrafluoroethylene, nor of siloxane group, but based on having very low glass transition temperatures (eg Tg = -36 to -50 ° C). 2. Sulfonated fluorinated elastomers according to claim 1 compounds hexafluoropropene (HFP), vinylidene fluoride (VDF) and fluoride perfluorosulfonyl ethoxy propyl vinyl ether (PSEPVE) or perfluoro (4-methyl- 3.6-dioxaoct-7-ene) sulfonyl fluoride (PFSO2F).

3. Sulfonated fluorinated elastomers according to claim 1 or 2 containing 20 to 32 % of HFP and 80 to 68% of PSEPVE or PFSO2F. 4. Sulfonated fluorinated elastomers according to claim 1 or 3 can also contain VDF. 5. Sulfonated fluorinated elastomers according to claim 1, 3 or 4 containing 10 to 32% of HFP, from 19 to 79% of PSEPVE or PFSO2F and from 0 to 71% of VDF. 6. Sulfonated fluorinated elastomers according to claim 1, 3 or 5 prepared in vintage ("Batch"). 7. Sulfonated fluorinated elastomers according to claim 1, 3, 5 or 6 synthesized by radical copolymerization in the presence of commercial organic initiators. 8. Sulfonated fluorinated elastomers according to claim 1, 3, 5, 6 or 7 prepared in presence of peroxides. 9. sulfonated fluorinated elastomers according to claim 1, 3, 5, 6 or 8 obtained mainly from t-butyl peroxypivalate. 10. Sulfonated fluorinated elastomers according to 1 claim 1, 3, 5, 6 or 9, the copolymerization is carried out either in emulsion, or in emulsion, in suspension, in microsuspension or in solution. 11. Sulfonated fluorinated elastomers according to claim 1, 3, 5, 6, 9 or 10 whose copolymerization is particularly carried out in solution, in the presence of solvents classic and commercial organic. 12. Sulfonated fluorinated elastomers according to claim 1, 3, 5, 6 or 10 requiring perfluoro-n-hexane, methyl acetate or acetonitrile as solvents. 13. Sulfonated fluorinated elastomers according to claim 1, 3, 5, 6, 10 or 12 synthesized in particular with acetonitrile and perfluoro-n-hexane. 14. Sulfonated fluorinated elastomers according to claim 1, 3, 5, 6, 10 or 13 prepared from initial molar ratios C0 = [initiator] 0 / ([HFP] 0 +
[VDF] 0 +
[PSEPVE] 0) or C0 = [initiator] 0 / ([HFP] 0 + [VDF] 0 + [PFSO2F] 0) lying between 0.4 and 2%. 15. Sulfonated fluorinated elastomers according to claim 1, 3, 5, 6, 10, 13 or suitable for the production of polymer electrolytes, ionomers, batteries at fuels; for obtaining seals, hoses, pipes, O-rings, pump body, diaphragms, piston heads (finding applications in industries aeronotic, petroleum, automotive, mining, nuclear) and for the plastics industry (products help setting in ~ uvre, "aid-processing").