Fluoroether unit-based thermostable, low-Tg and thermosetting cross-linked materials

Abstract

The present invention relates to a cross-linkable composition comprising: i) a fluorinated ,-bis(propargyl) oligomer of formula (I): in which m is 1 to 100, e.g. 1 to 93, n is 2 to 150, e.g. 1 to 128, p is 0 to 2, preferably 0 or 1.75, and n, m and p are selected such that the fluorinated ,-bis(propargyl) oligomer of formula (I) has a number average molar mass Mn of 400 to 25000; ii) a cross-linking agent comprising at least three azide-N.sub.3 groups; and iii) optionally, a fluorinated oligomer comprising two terminal azide-N3 or fluorinated ,-bis(azide) oligomer groups. The invention also relates to a material comprising the click chemistry reaction product of the cross-linkable composition of the invention, to a method for preparing said material and to the uses thereof.

Claims

1. A cross-linkable composition, comprising: i) a fluorinated ,-bis(propargyl) oligomer of formula (I): ##STR00025## wherein m is 1 to 100, n is 2 to 150, and p is 0 to 2, n, m and p being selected such that the fluorinated ,-bis(propargyl) oligomer of formula (I) has a number-average molar mass (M.sub.n) of 400 to 25000 as measured by .sup.19F NMR spectroscopy; ii) a cross-linking agent of formula (III): ##STR00026## wherein R.sub.3 is a hydrogen atom, a C.sub.1-C.sub.6 aliphatic group, or an aromatic group, Y is a group selected from H, OH, an aromatic group, a C.sub.1-C.sub.6 aliphatic group, or an O(CH.sub.2).sub.sP(O)(OR.sub.4).sub.2 group, s an integer from 2 to 20, R.sub.4 being H or a C.sub.1-C.sub.6 aliphatic group; and iii) optionally, a fluorinated oligomer comprising two terminal azide (N.sub.3) groups.

2. The cross-linkable composition according to claim 1, wherein respective molar proportions of oligomers (i) and (iii) and of cross-linking agent (ii) are such that a total number of propargyl (CH.sub.2CCH) groups is equal to a total number of azide (N.sub.3) groups.

3. The cross-linkable composition according to claim 1, wherein Y is OH, OCH.sub.2CH.sub.2P(O)(OH).sub.2 or OCH.sub.2CH.sub.2P(O)(OCH.sub.3).sub.2.

4. The cross-linkable composition according to claim 1, wherein the fluorinated ,-bis(azide) oligomer is represented by the following formula (IV):
N.sub.3CHR.sub.1(CHR.sub.2).sub.pR.sub.F(CHR.sub.2).sub.pCHR.sub.1N.sub.3(IV), wherein: radical R.sub.F is a fluorinated chain, p is 0 or 1, and R.sub.1 and R.sub.2 are independently selected from a hydrogen atom, a C.sub.1-C.sub.6 alkyl and a C.sub.2-C.sub.6 alkenyl.

5. The cross-linkable composition according to claim 4, wherein the fluorinated ,-bis(azide) oligomer is represented by the formula (V): ##STR00027## wherein: m is 1 to 100, n is 2 to 150, and p is 0 to 2, n, m and p being selected such that the fluorinated ,-bis(propargyl) oligomer of formula (I) has a number-average molar mass (M.sub.n) of 400 to 25000; or the fluorinated ,-bis(azide) oligomer is represented by the formula (VI):
N.sub.3CHR.sub.1CHR.sub.2(CR.sub.a1R.sub.b1CR.sub.c1R.sub.d1).sub.n1 . . . (CR.sub.aiR.sub.biC.sub.ciR.sub.di).sub.niCF.sub.2).sub.4(CR.sub.ciR.sub.diCR.sub.aiR.sub.bi).sub.ni . . . (CR.sub.c1R.sub.d1CR.sub.a1R.sub.b1).sub.n1CHR.sub.2CHR.sub.1N.sub.3(VI), wherein: R.sub.1 and R.sub.2 are independently selected from a hydrogen atom, a C.sub.1-C.sub.6 alkyl and a C.sub.2-C.sub.6 alkenyl, i is 1 to 20, CR.sub.a1R.sub.b1CR.sub.c1R.sub.d1 to CR.sub.a1R.sub.biCR.sub.ciR.sub.di are constitutional moieties, which may be identical or different, derived from monomers independently selected from the following fluorinated olefins: tetrafluoroethylene; vinylidene fluoride; hexafluoropropylene; trifluoroethylene; perfluoro(methyl vinyl ether); 3,3,3-trifluoropropene; 2,3,3,3-tetrafluoropropene; 1,3,3,3-tetrafluoropropene; chlorotrifluoroethylene; bromotrifluoroethylene; iodotrifluoroethylene; 2-chloro-3,3,3-trifluoropropene; vinyl fluoride; perfluoro(ethyl vinyl ether); perfluoro(propyl vinyl ether); 2-bromo-1,1-difluoroethylene; chlorodifluoroethylene; dichlorodifluoroethylene; 1,1,3,3,3-pentafluoropropene; 1,1,2,3,4,4-hexafluoro-1,3-butadiene; 1-propene, 1,1,3,3,3-pentafluoro-2-(trifluoromethyl)-1-propene; and derivatives thereof, and n.sub.1 to n.sub.i are each independently a number selected from 1 to 20.

6. The composition according to claim 1, wherein p is 1.75.

7. A material, comprising a product of a click-chemistry reaction of the cross-linkable composition according to claim 1 and having at least one glass-transition temperature value of 70 C. or lower.

8. The material according to claim 7, wherein the material has a decomposition temperature at 10% weight loss (T.sub.d.sup.10%) of 250 C. or higher, in air.

9. The material according to claim 7, wherein the material has at least one glass-transition temperature value of 80 C. or lower.

10. A process for preparing the material according to claim 7, the process comprising performing a cross-linking by click chemistry between: i) a fluorinated ,-bis(propargyl) oligomer of formula (I): ##STR00028## wherein: m is 1 to 100, n is 2 to 150, and p is 0 to 2, n, m and p being selected such that the fluorinated ,-bis(propargyl) oligomer of formula (I) has a number-average molar mass (M.sub.n) of 400 to 25000 as measured by .sup.19F NMR spectroscopy; ii) a cross-linking agent of formula (III): ##STR00029## wherein: R.sub.3 is a hydrogen atom, a C.sub.1-C.sub.6, aliphatic group, or an aromatic group, and Y is a group selected from H, OH, an aromatic group, a C.sub.1-C.sub.6 aliphatic group, an O(CH.sub.2).sub.sP(O)(OR.sub.4).sub.2 group, s an integer from 2 to 20, R.sub.4 being H or a C.sub.1-C.sub.6 aliphatic group, notably a methyl, ethyl or isopropyl group; and iii) optionally, a fluorinated oligomer comprising two terminal azide (N.sub.3) groups.

11. The process according to claim 10, wherein the cross-linking occurs in the presence of a copper catalyst.

12. An electrical insulator, comprising the material of claim 7.

13. The electrical insulator according to claim 12, which is suitable as an encapsulant for electronic cards in on-board systems or power modules, coatings for rotary machines or electric motors, semi-rigid packaging components, wiring.

14. The electrical insulator according to claim 12, wherein the material has a decomposition temperature at 10% weight loss (T.sub.d.sup.10%) of 250 C. or higher, in air.

Description

PRESENTATION OF THE FIGURES

(1) FIG. 1 shows the .sup.19F NMR spectrum in deuterated methanol (MeOH-d.sub.4) of poly(tetrafluoroethylene oxide-co-difluoromethylene oxide)-,-diol (Fomblin Z-DOL), and the calculation of the number-average molar mass (M.sub.n) (1200 g/mol). The x-axis represents chemical shifts in ppm.

(2) FIG. 2 shows a superposition of the .sup.19F NMR spectra in deuterated methanol (MeOH-d.sub.4) of poly(tetrafluoroethylene oxide-co-difluoromethylene oxide)-,-diol (Fomblin Z-DOL) and of the PFPE-dialkyne ether of Example 1. The x-axis represents chemical shifts in ppm.

(3) FIG. 3 shows the .sup.1H NMR spectrum in deuterated methanol (MeOH-d.sub.4) of the PFPE-dialkyne ether of Example 1. The x-axis represents chemical shifts in ppm.

(4) FIG. 4 shows a superposition of the infrared (FTIR) spectra of poly(tetrafluoroethylene oxide-co-difluoromethylene oxide)-,-diol (Fomblin Z-DOL) and of the PFPE-dialkyne ether of Example 1. The x-axis represents wavenumber (in cm.sup.1), and the y-axis represents transmittance (in %).

(5) FIG. 5 shows a superposition of the Fourier-transform infrared (FTIR) spectra of the pentaerythritol triazide of Example 5, and of the PFPE-dialkyne ether of Example 1 and of the binary material of Example 7.1, and the IR spectrum of the tribrominated precursor compound of pentaerythritol triazide. The x-axis represents wavenumber (in cm.sup.1), and the y-axis represents transmittance (in %).

(6) FIG. 6 shows a superposition of the thermogravimetric analysis (TGA) thermograms at 10 C. per minute in air, of the binary material of Example 7.1 and the precursors thereof, the pentaerythritol triazide of Example 5, and the PFPE-dialkyne ether of Example 1. The x-axis represents temperature (in C.), and the y-axis represents weight (in %).

(7) FIG. 7 shows the differential scanning calorimetry (DSC) analysis thermogram of the binary material of Example 7.1, The x-axis represents temperature (in C.), and the y-axis represents heat flow per unit mass (in mW/mg).

(8) FIG. 8 shows a superposition of the .sup.19F NMR spectra in deuterated methanol (MeOH-d.sub.4) of poly(tetrafluoroethylene oxide-co-difluoromethylene oxide)-,-diol (Fomblin Z-DOL) and of the ,-bis(tosylate) PFPE of step 1 of Example 2. The x-axis represents chemical shifts in ppm.

(9) FIG. 9 shows a superposition of the .sup.1H NMR spectra in deuterated methanol (MeOH-d.sub.4) of poly(tetrafluoroethylene oxide-co-difluoromethylene oxide) ,-diol (Fomblin Z-DOL) and of the ,-bis(tosylate) PFPE of step 1 of Example 2. The x-axis represents chemical shifts in ppm.

(10) FIG. 10 shows a superposition of the .sup.19F NMR spectra in deuterated methanol (MeOH-d.sub.4) of the ,-bis(tosylate) PFPE of step 1 of Example 2 and the ,-bis(azido) PFPE of step 2 of Example 2. The x-axis represents chemical shifts in ppm.

(11) FIG. 11 shows a superposition of the .sup.1H NMR spectra in deuterated methanol (MeOH-d.sub.4) of the ,-bis(tosylate) PFPE of step 1 of Example 2 and the ,-bis(azido) PFPE of step 2 of Example 2. The x-axis represents chemical shifts in ppm.

(12) FIG. 12 shows a superposition of the FTIR spectra of the ,-bis(tosylate) PFPE of step 1 of Example 2 and the ,-bis(azido) PFPE of step 2 of Example 2. The x-axis represents wavenumber cm.sup.1) and the y-axis represents transmittance (in %).

(13) FIG. 13 shows a superposition of the thermogravimetric analysis (TGA) thermograms at 10 C. per minute in air, of the ternary material of Example 7.2 and the precursors thereof, the pentaerythritol triazide of Example 5, and the PFPE-dialkyne ether of Example 1. The x-axis represents temperature (in C.), and the y-axis represents weight (in %).

(14) FIG. 14 shows the differential scanning calorimetry (DSC) analysis thermogram of the ternary material of Example 7.2. The x-axis represents temperature (in C.), and the y-axis represents heat flow (in mW/mg).

(15) FIG. 15 shows the differential scanning calorimetry (DSC) analysis thermogram of the ternary materials LG-75, LG-76, LG-77 and LG-78 of Example 7.3. The enthalpy of cross-linking is given in J/g. The x-axis represents temperature (in C.), and the y-axis represents heat flow (in mW/mg).

(16) FIG. 16 shows a schematic representation of the structural differences of the cross-linked materials according to the invention as a function of the proportion of cross-linking agent (ii) and of ,-bis(azide) oligomer (iii) in the starting cross-linkable composition. The arrow indicates the direction of an increasing proportion of cross-linking agent (ii). The structure of a cross-linking point is indicated beneath the arrow.

(17) FIG. 17 describes the kinetic change (160 C.) in the viscoelastic moduli of the binary reactive formulation (i)+(ii) in a 3.2 molar ratio. The x-axis represents time (in min), and the y-axis represents moduli G and G (in Pa).

(18) FIG. 18 shows the .sup.19F NMR spectrum in deuterated acetone ((CH.sub.3).sub.2CO-d.sub.6) of Fluorolink E10H. The x-axis represents chemical shifts in ppm.

(19) FIG. 19 shows a superposition of the .sup.1H NMR spectra in deuterated acetone ((CH.sub.3).sub.2CO-d.sub.6) of Fluorolink E10H and of the PFPE-dialkyne ether A of Example 3. The x-axis represents chemical shifts in ppm.

(20) FIG. 20 shows a superposition of the FTIR spectra of Fluorolink E10H and of the PFPE-dialkyne ether A of Example 3. The x-axis represents wavenumber (in cm.sup.1), and the y-axis represents transmittance (in %).

(21) FIG. 21 shows a superposition of the .sup.1H NMR spectra in deuterated acetone ((CH.sub.3).sub.2CO-d.sub.6) of Fluorolink E10H and of the ,-bis(tosylate) PFPE of step 1 of Example 4. The x-axis represents chemical shifts in ppm.

(22) FIG. 22 shows a superposition of the .sup.1H NMR spectra in deuterated acetone ((CH.sub.3).sub.2CO-d.sub.6) of the ,-bis(tosylate) PFPE of step 1 of Example 4 and of the ,-bis(azido) PFPE B of step 2 of Example 4. The x-axis represents chemical shifts in ppm.

(23) FIG. 23 shows a superposition of the FTIR spectra of Fluorolink E10H, of the ,-bis(tosylate) PFPE of step 1 of Example 4, and of the ,-bis(azido) PFPE B of step 1 of Example 4. The x-axis represents wavenumber (in cm.sup.1), and the y-axis represents transmittance (in %).

(24) FIG. 24 shows the differential scanning calorimetry (DSC) analysis thermograms of mixtures A+C (1:0.67, mol/mol) and A+C+C (1:0.603:0.067). The enthalpy of cross-linking is given in J/g. The x-axis represents temperature (in C.), and the y-axis represents heat flow (in mW/mg). Solid line: mixture A+C+C; dotted line: mixture A+C.

EXAMPLES

(25) The present invention is illustrated by the following examples, which may not however be regarded as limiting.

(26) TABLE-US-00001 Abbreviations: Eq. Molar equivalent NMR Nuclear magnetic resonance IR Infrared FTIR Fourier-transform infrared DMSO Dimethylsulfoxide DMF Dimethylformamide DSC Differential scanning calorimetry TGA Thermogravimetric analysis

Example 1: Synthesis of PFPE-Dialkyne Ether (Oligomer A)

(27) ##STR00017##

(28) Poly(tetrafluoroethylene oxide-co-difluoromethylene oxide)-,-diol (Fomblin Z-DOL, M.sub.n 1200 g/mol (FIG. 1), 20 g, 16.7 mmol, 1 eq.) is added to a mixture of CH.sub.3CN (80 mL) and THF (80 mL), also containing sodium hydroxide (3.2 g, 83.5 mmol, 5 eq.). This suspension is heated to 55 C. under nitrogen atmosphere. Propargyl bromide (80 wt % solution in toluene, 10 mL, 83.5 mmol, 5 eq.) is added to the reaction mixture. The latter is heated to 55 C. under vigorous stirring for 3 days (>250 rpm). The reaction mixture is then cooled, filtered over a medium frit and the solvent is evaporated. The crude product is dried under vacuum (90.Math.10.sup.3 mbar) and then purified by filtration through a 0.22 mm polyethersulfone filter, 17.5 g (82%) of light brown viscous oil is obtained.

(29) The .sup.19F and .sup.1H NMR spectra are shown in FIG. 2 and FIG. 3, respectively, and the FTIR spectrum in FIG. 4.

Example 2: Synthesis of ,-bis(azido) PFPE (Oligomer B)

(30) ##STR00018##

Step 1. Synthesis of ,-bis(tosylate) PFPE

(31) Poly(tetrafluoroethylene oxide-co-difluoromethylene oxide)-,-diol (Fomblin Z-DOL, M.sub.n 1200 g/mol, 1 g, 0.83 mmol, 1 eq.) is dissolved in a mixture of ,,-trifluorotoluene (10 mL) and triethylamine (210 mg, 2 mmol, 2.5 eq.). Tosyl chloride (400 mg, 2 mmol, 2.5 eq.) is added to the reaction mixture, which is heated to 55 C. under vigorous stirring for 24 hours. Next, 10 mL of water and 1 mL of MeOH are added to the reaction mixture. The hydroalcoolic phase is removed, and the crude product is dried under reduced pressure (90.Math.10.sup.3 mbar) at 100 C. 1.15 g (92%) of light brown oil is obtained. The .sup.19F and .sup.1H NMR spectra are shown in FIG. 8 and FIG. 9, respectively, and the infrared (FTIR) spectrum in FIG. 12.

Step 2. Synthesis of ,-bis(azido) PFPE

(32) A mixture of ,-bis(tosylate) PFPE (1 g, 0.66 mmol, 1 eq.), NaN.sub.3 (260 mg, 3.98 mmol, 6 eq.), and DMSO (20 mL) is stirred at 110 C. for 3 days. The reaction mixture is then poured into water (100 mL), and then extracted with 1,1,1,3,3-pentafluorobutane (350 mL). The organic phases are combined, washed with water (350 mL), dried (MgSO.sub.4), filtered and concentrated under vacuum. 770 mg (93%) of light brown oil is obtained.

(33) The .sup.19F NMR and .sup.1H spectra are shown in FIG. 10 and FIG. 11, respectively, and the infrared (FTIR) spectrum in FIG. 12.

Example 3: Synthesis of PFPE-Dialkyne Ether (Oligomer A)

(34) ##STR00019##

(35) Fluorolink E10H (FIG. 19, 1800 g/mol, 100 g, 55.6 mmol, 1 eq.) is added to a mixture of CH.sub.3CN (150 mL) and THF (150 mL), also containing sodium hydroxide (16 g, 400 mmol, 7.2 eq.). This suspension is heated to 55 C. under nitrogen atmosphere. Propargyl bromide (80 wt % solution in toluene, 50 mL, 449 mmol, 8.1 eq.) is added to the reaction mixture. The latter is heated to 55 C. under vigorous stirring (>250 rpm) for 7 days. The reaction mixture is then cooled, filtered under vacuum and the solvent is evaporated. The crude product is dried under vacuum (20.Math.10.sup.3 mbar) at 100 C. and then purified by filtration through a 0.45 m PTFE filter. 86 g (about 85%) of light brown oil is obtained. The .sup.1H NMR spectrum is presented in FIG. 19, and the FTIR spectrum in FIG. 20. Differential scanning calorimetry analysis revealed a glass-transition temperature of 100 C.

Example 4: Synthesis of ,-bis(azido) PFPE (Oligomer B)

Step 1. Synthesis of ,-bis(tosylate) PFPE

(36) ##STR00020##

(37) Fluorolink E10H (1800 g/mol, 100 g, 55.6 mmol, 1 eq.) is dissolved in a mixture of 1,1,1,3,3-pentafluorobutane (300 mL) and triethylamine (28 g, 277 mmol, 5 eq.). Tosyl chloride (53 g, 278 mmol, 5 eq.) is added to the reaction mixture, which is heated to 30 C. under vigorous stirring for 7 days. The fluorinated phase is then washed with water (3300 mL), dried over MgSO.sub.4, filtered, and then evaporated under reduced pressure. The crude product is then dried under reduced pressure (20.Math.10.sup.3 mbar) at 100 C. 70 g (about 70%) of light brown oil is obtained. The .sup.1H NMR spectrum is presented in FIG. 21, and the FTIR spectrum in FIG. 23.

Step 2. Synthesis of ,-bis(azido) PFPE B

(38) ##STR00021##

(39) A mixture of ,-bis(tosylate) PFPE (70 g, 38.9 mmol, 1 eq.) synthesized during the first step, NaN.sub.3 (27 g, 415 mmol, 10.7 eq.), and DMSO (300 mL) is stirred at 100 C. for 7 days. The reaction mixture is then poured into water (300 mL), and then extracted with 1,1,1,3,3-pentafluorobutane (3150 mL). The organic phases are combined, washed with water (3150 mL), dried (MgSO.sub.4), filtered and concentrated under vacuum. The crude product is then dried under reduced pressure (20.Math.10.sup.3 mbar) at 100 C., 42 g (about 60%) of light brown oil is obtained. The .sup.1H NMR spectrum is presented in FIG. 22, and the FTIR spectrum in FIG. 23. Differential scanning calorimetry analysis revealed a glass-transition temperature of 105 C. and a degradation temperature of about 180 C.

Example 5: Synthesis of Pentaerythritol Triazide (Cross-Linking Agent C)

(40) ##STR00022##

(41) This synthesis employs as starting compound 3-bromo-2,2-bis(bromomethyl)propanol (commercial product available for example from ABCR), according to a protocol described notably in Dalton Trans. 2012, 41, 4335; Biomaterials 2014, 35, 2322: Chem. Commun. 2007, 380; WO2012131278.

(42) A mixture of 3-bromo-2,2-bis(bromomethyl)propanal (10 g, 31 mmol, 1 eq.), NaN.sub.3 (12 g, 186 mmol, 6 eq.), and DMSO (30 mL) is mixed at 100 C. for 2 days. The reaction mixture is then poured into water (200 mL) and then extracted with chloroform (CHCl.sub.3; 3100 mL). The organic phases are combined and then washed with water (3100 mL), dried (MgSO.sub.4), filtered and concentrated under reduced pressure to give 5.70 g (87%) of pale yellow oil.

(43) .sup.1H NMR (CDCl.sub.3), (ppm): 2.20 (br. s, 1H, OH); 3.36 (s, 6H, CH.sub.2N.sub.3); 3.52 (s, 2H, CH.sub.2OH).

(44) FTIR-ATR: 2100 cm.sup.1 (.sub.N3); 3400 cm.sup.1 (.sub.OH).

Example 6: Phosphorus-Containing Cross-Linking Agent (Cross-Linking Agent C)

(45) ##STR00023##

(46) Pentaerythritol triazide (2 g, 9.47 mmol, 1 eq.) is heated for 16 hours at 50 C. in the presence of dimethyl vinylphosphonate (1.29 g, 9.47 mmol, 1 eq.) and cesium carbonate (3.08 g, 9.47 mmol, 1 eq.). The reaction medium is then diluted with water (100 mL) and then extracted with ethyl acetate (3100 mL). The organic phases are combined, dried (MgSO.sub.4), and then evaporated under reduced pressure. The residue is purified by silica-gel column chromatography (eluent: dichloromethane/ethyl acetate, 90:10) to give 760 mg (23%) of colorless oil.

(47) .sup.1H NMR (CDCl.sub.3), (ppm): 2.09 (dt, 2H, PCH.sub.2, .sup.2J.sub.HP=18.6 Hz, .sup.3J.sub.HH=7.3 Hz); 3.28 (s, 2H, OCH.sub.2C(CH.sub.2N.sub.3).sub.3; 3.32 (s, 6H, OCH.sub.2C(CH.sub.2N.sub.3).sub.3; 3.68 (dt, 2H, PCH.sub.2CH.sub.2, .sup.3J.sub.HP=13.2 Hz, .sup.3J.sub.HH=7.3 Hz); 3.73 (d, 6H, CH.sub.3O, .sup.3J.sub.HP=10.9 Hz).

(48) .sup.13C NMR (CDCl.sub.3), (ppm): 25.9 (d, PCH.sub.2, .sup.1J.sub.CP=140.4 Hz); 45.0 (C(CH.sub.2N.sub.3).sub.3); 51.2 (C(CH.sub.2N.sub.3).sub.3); 52.5 (d, CH.sub.3O, .sup.2J.sub.CP=6.5 Hz); 65.3 (d, PCH.sub.2CH.sub.2, .sup.2J.sub.CP=1.8 Hz); 69.3 (OCH.sub.2C(CH.sub.2N.sub.3).sub.3).

(49) .sup.31P NMR (CDCl.sub.3), (ppm): 30.7

(50) The latter is diluted in dichloromethane (10 mL) and then trimethylsilyl bromide (about 0.5 mL) is added dropwise. The reaction medium is left for 16 hours at room temperature before being concentrated under reduced pressure. The residue is then diluted with a methanol water mixture (10 mL/10 mL) for 16 hours at room temperature. After evaporation, a slightly yellow oil is obtained (420 mg, 100%).

(51) .sup.1H NMR (CDCl.sub.3), (ppm); 2.15 (dt, 2H, PCH.sub.2, .sup.2J.sub.HP=16.5 Hz, .sup.3J.sub.HH=7.1 Hz); 3.27 (s, 2H, OCH.sub.2C(CH.sub.2N.sub.3).sub.3; 3.29 (s, 6H, OCH.sub.2C(CH.sub.2N.sub.3).sub.3; 3.72 (dt, 2H, PCH.sub.2CH.sub.2, .sup.3J.sub.HP=12.8 Hz, .sup.3J.sub.HH=7.1 Hz); 9.49 (br s, 1H, HO).

(52) .sup.13C NMR (CDCl.sub.3), (ppm): 26.5 (d, PCH.sub.2, .sup.1J.sub.CP=145.6 Hz); 44.7 (C(CH.sub.2N.sub.3).sub.3); 51.8 (C(CH.sub.2N.sub.3).sub.3); 65.0 (PCH.sub.2CH.sub.2); 69.6 (OCH.sub.2C(CH.sub.2N.sub.3).sub.3).

(53) .sup.31P NMR (CDCl.sub.3), (ppm): 32.5

Example 7: Cross-Linked Materials

(54) 7.1. Cross-Linking By Click Chemistry with PFPE-Dialkyne Ether and Pentaerythritol Triazide (Binary Material)

(55) ##STR00024##

(56) PFPE-dialkyne ether (4.55 g, 3.57 mmol, 1 eq.) and pentaerythritol triazide (810 mg, 3.83 mmol, 1.07 eq.) are suspended in DMF (20 mL). The mixture is degassed by nitrogen bubbling for 30 minutes. Next, CuBr (52 mg, 0.036 mmol, 0.1 eq.) and N,N,N,N,N-pentamethyldiethyenetriamine (PMDETA, 62 mg, 0.036 mmol, 0.1 eq.) are added to the reaction medium which instantaneously turns green. After stirring for 1 hour, the insoluble polymer is washed several times with a DMF:PMDETA mixture (20 mL:1 mL) until the rinse solution remains colorless. The polymer is then dried under vacuum at 100 C. until a constant weight is obtained (4.40 g, 82 wt %).

(57) The polymer is then analyzed by infrared spectroscopy (FTIR, FIG. 5).

(58) Thermogravimetric analysis (TGA) reveals a decomposition temperature at 10% weight loss (T.sub.d.sup.10%) of 280 C., in air. (FIG. 6). Differential scanning calorimetry analysis reveals a glass-transition temperature (T.sub.g) value at 87 C. (FIG. 7).

(59) 7.2. Click Cross-Linking with PFPE-Dialkyne Ether, ,-bis(azido) PFPE and Pentaerythritol Triazide (Ternary Material)

(60) PFPE-dialkyne ether (472 mg, 0.37 mmol, 0.525 eq.), ,-bis(azido) PFPE (400 mg, 0.32 mmol, 0.450 eq.) and pentaerythritol triazide (10 mg, 0.04 mmol, 0.05 eq.) are suspended in DMF (20 mL). The mixture is degassed by nitrogen bubbling for 30 minutes. Next, CuBr (10 mg, 0.07 mmol, 0.1 eq.) and N,N,N,N,N-pentamethyldiethylenetriamine (PMDETA, 10 mg, 0.07 mmol, 0.1 eq.) are added to the reaction medium which instantaneously turns green. After stirring for 1 hour, the insoluble polymer is washed several times with a DMF:PMDETA mixture (20 mL:1 mL) until the rinse solution remains colorless. The polymer is then dried under vacuum at 100 C. until a constant weight is obtained (800 mg, 91 wt %).

(61) Kinetic rheological analysis (FIG. 17) reveals that the gel point associated with critical production of the polymer network is detected by the divergence of the viscoelastic moduli. The associated gel time is about 6 minutes at a temperature of 160 C. whereas the reaction seems to have reached a maximum degree of advancement after 30 minutes. These values underscore that the mixture has a reactivity which is perfectly compatible with the productivity demands of an industrial process.

(62) Thermogravimetric analysis (TGA) reveals a decomposition temperature at 10% weight loss (T.sub.d.sup.10%) of 291 C. in air (FIG. 13). Differential scanning calorimetry analysis reveals a glass-transition temperature (T.sub.g) value at 100 C. (FIG. 14).

(63) 7.3. Ternary Formulations with Pentaerythritol Triazide of Examples 1 and 2: Variation of the Proportion of Cross-Linking Agent

(64) Four materials were prepared with variable ratios of ,-bis(azide) oligomers/cross-linking agent (here, pentaerythritol triazide) in the starting cross-linkable composition. They are designated as follows:

(65) LG-75: material obtained by cross-linking of a cross-linkable composition within which 20% of the azide functions are provided by the cross-linking agent (i.e., the remaining 80% are provided by the ,-bis(azide) oligomer, ,-bis(azido) PFPE):

(66) LG-76: material obtained by cross-linking of a cross-linkable composition within which 40% of the azide functions are provided by the cross-linking agent (i.e., the remaining 60% are provided by the ,-bis(azide) oligomer, ,-bis(azido) PFPE);

(67) LG-77: material obtained by cross-linking of a cross-linkable composition within which 60% of the azide functions are provided by the cross-linking agent (i.e., the remaining 40% are provided by the ,-bis(azide) oligomer, ,-bis(azido) PFPE).

(68) LG-78: material obtained by cross-linking of a cross-linkable composition within which 80% of the azide functions are provided by the cross-linking agent (i.e., the remaining 20% are provided by the ,-bis(azide) oligomer, ,-bis(azido) PFPE).

(69) The comparative study of the calorimetric behavior of these four materials as a function of temperature is shown in FIG. 15.

(70) Material LG-75 is that which contains the least cross-linking agent. Its reaction field, appears to be composed of two exotherms.

(71) The increase in the content of cross-linking agent with formulation LG-76 leads to an increase in the total enthalpy of cross-linking. In other words, substitution of the ,-bis(azide) oligomers with the cross-linking agent induces a greater heat release. The high-temperature shoulder shifts towards the higher temperatures, revealing a difference in reactivity between the two azide-containing molecules (cross-linking agent and ,-bis(azide) oligomer) with respect to the ,-bis(propargyl) oligomer.

(72) The same tendencies are exacerbated with the mixture highest in cross-linking agent (i.e., formulation LG-78).

(73) It is important to note that, despite the difference in reactivity of the azide-containing molecules (cross-linking agent and ,-bis(azide) oligomer), the cross-linking reaction is quantitative. Thus, preparation of the mixture in stoichiometric amounts (i.e., in the cross-linkable compositions leading to materials LG-75, LG-76, LG-77 and LG-78, the respective molar proportions of oligomers (i), (ii) and (iii) are such that the total number of propargyl (CH.sub.2CCH) groups is equal to the total number of azide (N.sub.3) groups) ensures total consumption of the reactive species.

(74) The lowest T.sub.g of the order of 100 C., as for it, is observed with the formulation lowest in cross-linking agent, which is consistent with the fact that the network is produced by highly flexible perfluorinated links.

(75) 7.4. Ternary Formulations with Pentaerythritol Triazide and Oligomers A and B (Examples 3 and 4): Variation of the Proportion of Cross-Linking Agent C

(76) Six materials were prepared with variable ratios of ,-bis(azide) oligomers/cross-linking agent (here, pentaerythritol triazide C) in the starting cross-linkable composition (formulations F1 to F6 below):

(77) TABLE-US-00002 Percentage of azide functions name provided by C F1 100% F2 80% F3 60% F4 40% F5 20% F6 7%

(78) Infrared spectroscopy analyses confirmed the disappearance of the bands characteristic of alkyne- and azide-type groups. The polymerization is thus quantitative. The increase in the content of cross-linking agent leads to an increase in the total enthalpy of cross-linking (measured by differential calorimetric analysis): H(F1)=188 J/g, H(F2)=185 J/g, H(F3)=172 J/g, H(F4)=148 J/g, H(F5)=141 J/g, H(F6)=137 J/g.

(79) Kinetic rheological analyses at 120 C. make it possible to monitor the reaction of the three reactive species. In all cases, the formulations lead to thermosetting matrices. The gel time thereof (associated with the minimum duration necessary for critical formation of a percolating network) is evaluated by time corresponding to the divergence of the viscoelastic moduli. They are 0.8, 1.2, 1.8, 3.5, 8.25 and 16 hours for formulations F1, F2, F3, F4, F5 and F6, respectively. In other words, gel time increases when the proportion of cross-linking agent decreases in the reaction formulation. At the same time, mechanical stiffness also decreases with the decreasing content of cross-linking agent.

(80) Calorimetric analyses carried out on the formulations after total consumption of the reactive species show the presence of two glass-transition temperatures. The one recorded at low temperature is inherent to the (macro)molecular PFPE segments given by A and/or B. It is considered the secondary T.sub.g and remains constant (independent of the content of cross-linking agent) at about 103 C. The one observed at higher temperature, considered the principal T.sub.g of the polymer network, decreases with a decreasing proportion of cross-linking agent due to a larger, more flexible polymer mesh. It ranges from about 25 C. for formulation F1, to about 85 C. for formulation F6.

(81) Finally, thermogravimetric analyses carried out under oxidizing atmosphere confirmed the formation of material having high thermal stability, with a decomposition temperature at 10% weight loss (T.sub.d.sup.10%) higher than 300 C. for the six compositions F1 to F6.

Example 8: Polymerization with a Phosphorus-Containing Cross-Linking Agent

(82) The enthalpy of cross-linking of an A+C binary mixture is determined by DSC, using the Proteus Analysis software. It is of the same order of magnitude as that of an A+C mixture containing 10% molar C (see FIG. 24). The presence of the phosphorus group is thus not in itself an element that disrupts the overall reactivity of the mixture.