FR2694297A1 - Hydroxyl terminated prepolymers and oxetane monomers for preparing them. - Google Patents

Abstract

The invention relates to oxetane-type monomers having one or two fluorinated alkoxy side chains. The monomers of the oxetane type correspond to the formula: (CF DRAWING IN BOPI) where n is 1 to 5; m is 1 or 2; R is hydrogen or an alkyl group having 1 to 4 carbon atoms; and Rf is a straight or branched chain perfluorinated alkyl, isoalkyl, haloalkyl, halisoalkyl having 1 to 20 carbon atoms, or an oxa-perfluorinated polyether having 4 to about 60 carbon atoms. These monomers are readily polymerizable by opening the oxetane ring to form prepolymers terminated by hydroxyl groups. Applications to hydrophobic non-stick coatings and binders for propellants.

Description

The present invention relates to oxetane type monomers having

  Lateral perfluoroalkoxy groups, a process for their preparation and a process for their polymerization, and the hydroxyl terminated prepolymers thus prepared The prepolymers have a polyether backbone and are useful for the preparation of resins and coatings having hydrophobic properties, low dielectric constant and low refractive index. It is known that oxetane can be substituted at the 3-position by methyl groups containing energetic functional groups such as nitrato, azido, nitro and difluoramino. The polymerization of these substituted oxetanes in the presence of polyhydroxylated aliphatic compounds produces polymers terminated in groups. hydroxyl having a polyether backbone bearing side energy groups These polymers can then be cured with isocyanates to form high weight polymers

  which are useful as binders in

  with propellants, as described in the

  U.S. Patent Nos. 4,393,199, 4,483,978, 4,707,540 and 4,764,586.

  it is advantageous to incorporate fluorine in the polymers of the polyether type; however, the incorporation of high percentages of fluorine in the ether skeleton of a polymer results in thermal and chemical instability leading to the generation of fluoride ions or hydrogen fluoride When fluorine is incorporated into polymers without ether linkage, the resulting materials have high glass transition temperatures which limit

  the utility and applications of the resulting polymers.

  The present invention relates to oxetane monomers having alkoxy side chains where an omega-carbon atom is fully fluorinated, preferably perfluorinated alkoxy side chains, a process for their preparation, a process for their polymerization and the resulting prepolymers. are prepared by the reaction of the corresponding fluorinated alkoxides with

  arylsulfonates or halogenated derivatives of 3-hydroxyalkyl-

  oxetanes An example of these is the p-toluene-

  3-hydroxymethyl-3-methyl-oxetane or 3,3 bis (hydroxymethyl) oxetane sulfonate A high yield of oxetanes having side perfluoroalkoxy chains is obtained. The fluorinated alkoxy-chain oxetane (s) monomers of the present invention can be readily polymerized in the presence of Lewis acids as catalysts to produce, in high yields, prepolymers

  terminated by hydroxyl groups having molecular weights

  from about 1000 to about 30,000 and a polyether backbone resulting from the opening of the oxetane ring. These prepolymers are useful as hydrophobic antiadhesive coatings and

  as propellant binder precursors.

  The present invention covers the following oxetane derivatives, a process for their preparation, a process for their polymerization and the resulting prepolymers: R; m) CH (CH 2) n Rf 1 m c 0 /

CH 2 ^^ CH 2

  where: n is 1 to 5; m is 1 or 2; R is hydrogen or an alkyl group having 1 to 4 carbon atoms; and

  Rf is an alkyl, isoalkyl, halogeno

  alkyl, linear or branched chain perfluorinated halogenisoalkyl having 1 to 20 carbon atoms, or an oxa-perfluorinated polyether having

4 to about 60 carbon atoms.

  The invention also covers the polymerization of the monomer and the resulting hydroxyl-terminated prepolymers having the structure schematized below: CH 2 (CH 2) n R f 1 H 2 O-CH 2-C-CH 2 1 x R 1 OH R 2 -m or is 1 to 5; m is 1 or 2; Rest hydrogen or an alkyl group having 1 to 4 carbon atoms; R 1 is an alkylene or isoalkylene group having 2 to about 5 carbon atoms;

  Rf is an alkyl, isoalkyl, halogeno

  alkyl, linear or branched chain perfluorinated halogenisoalkyl having 1 to 20 carbon atoms, or an oxa-perfluorinated polyether having 4 to about 60 carbon atoms; and

x is from 2 to about 250.

  The oxetane derivatives are obtained by the reaction of arylsulfonates of hydroxyalkyl oxetanes with fluorinated alkoxides. The arylsulfonates of the hydroxyalkyl oxetanes have the general formula: R 2 CCH 2 OSO 2 R 3 1 m

C / CH 2

  o: m is 1 or 2; R is hydrogen or an alkyl group having 1 to 4 carbon atoms; and R 3 is a monocyclic aryl group having 6 to 10 carbon atoms, for example benzyl, tolyl, xylyl, mesityl. The preferred sulfonates are toluenesulfonates,

  for example p-toluenesulfonates derived from oxetane.

  The fluorinated alcoholates are obtained by the reaction of fluorinated alcohols with sodium hydride in a suitable solvent such as dimethylformamide. The fluorinated alcohols which may be used correspond to the general formula: Rf (CH 2) n OH or: n is 1 to 5,

  Rf is an alkyl, isoalkyl, halogeno

  alkyl, linear or branched chain perfluorinated halogenisoalkyl having 1 to 20 carbon atoms, or an oxa-perfluorinated polyether having

4 to about 60 carbon atoms.

  Examples of suitable fluorinated alcohols are:

  fluorethanol, heptafluorobutanol, pentadecafluoro-

  octanol, tridecafluoroctanol, etc. Other useful alcohols include fluorinated alcohols having other halogens at the omega position, for example the omega-haloperfluoro alcohols of the following formulas: 1 HOCH 2 (CF 2) n CF 2 X and 2 HOCH 2 (CF 2 CF) n CF 2 X CF 3 o: X is a halogen, for example bromo, iodine, chlorine or fluorine; and n is from 2 to about 20; and 3 HOCH 2 (OCF 2 CF 2) n F, and 4 HOCH 2 (OCF 2 CF) n F n CF 3 o N is from 2 to about 20. The fluorinated alkoxy-chain oxetane type monomers (s) are ) are readily polymerized in the presence of a Lewis acid as a catalyst and a polyhydroxylated aliphatic compound as a polymerization initiator. In the presence of a Lewis acid, the alcohol liberates a proton which initiates the polymerization by open-cell dexylate, which continues with the formation of the following intermediate species:

R C R

  Suitable catalysts are Lewis acids, i.e. compounds capable of accepting a doublet.

  electronics, examples of which are

  boron fluoride, phosphorus pentafluoride, penta

  antimony fluoride, zinc chloride, aluminum bromide, etc. Suitable initiators are compounds

  polyhydroxy aliphatics such as alkyl and isoalkyl

  polyols having 2 to about 5 carbon atoms and 2 to 4 hydroxyl groups, for example ethylene glycol, butane-1,4-diol, propylene glycol, isobutane-1,3-diol, pentane -1,5-diol, pentaerythritol, etc. The polymerization is carried out in the presence of a suitable inert solvent, preferably a C1 to C5 halogenated hydrocarbon, for example methylene chloride, methylene bromide, ethylene chloride, ethylene bromide, chlorine and the like. propylene, Freons, fluorinated solvents, etc. The catalyst and the initiator are preferably mixed in the solvent before being added to the oxetane monomer. An example of a preferred combination

  catalyst, initiator and solvent is the boron trifluoride ether complex or boron trifluoride tetrahydrofuran complex, and 1,4-butanediol in methylene chloride.

  The monomer is added to this mixture and solution polymerization is carried out at concentrations of 5 to 75 percent by weight in the solution. For the polymerization, the catalyst concentration and the proportion of the initiator can be varied. for example butane-1,4-diol, to regulate the molecular weight of the polymer, the highest proportions of initiator leading to lower molecular weight prepolymer product Useful ratios between the boron trifluoride catalyst and the initiator may vary from approximately

: 1 to about 1: 2.

  The polymerization ends with the formation of

  polymer terminated by hydroxyl groups according to the

following:

R C R R

I / I

  The polymerization may be a homopolymerization or a copolymerization in which a mixture of two or more of the oxetane type monomers described above is used.

  is introduced into the polymerization zone A copolymer

  particularly interesting is a polymerisation

  in which the comonomers are successively added in selected proportions to produce block copolymers having sequence sizes and

well-defined properties.

  To prepare prepolymers with optimum properties for coating applications, the oxetane monomer must have a 3-substituent in which the Rf-group omega carbon atom is completely fluorinated. One of the major applications of the prepolymers terminated by The most important condition in the development of these coatings is to minimize the free surface energy of the coating, which is a measure of the wettability of the coating. and determines essential properties such as its hydrophobicity and adhesive characteristics. The terminal carbon atoms which contain hydrogen, for example -CF 2 H, -CFH 2 or -CH 3, have much higher surface energies ( 15 to 39 x 10-3 N / m) than those presented by completely halogenated groups, examples are those presented by groups -CF 3, whose surface energies are

about 6 x 10 3 N / m.

  At best, the substituent at 3 (Rf) is a perfluoroalkyl group. The perfluoroalkyl group is an extremely strong electro-attractant group and its presence modifies the electronic and steric properties of the oxetane type monomers. This has an effect on the ease of their polymerization. and the functionality, molecular weight and structure, i.e. cyclic or linear, of the polymer. The most useful of the hydroxyl terminated prepolymers having fluorinated side chains are those which are well defined and which have functionality of at least 2 The presence of species

  non-functional or monofunctional in the prepoly-

  mothers leads to coatings whose mechanical properties

  and surface properties are poor.

  Cyclic groups, mainly cyclic tetramers and trimers, contained in the polymer are not

  not functional and decrease the usefulness of the prepolymers.

  Other non-functional groups may be formed by complementary ion terminations, for example diethyl ether and fluoride ion terminations. In addition to the function exerted by the fluoralkyl substituent on

  oxetane on its reactivity, other factors

  Thus, the formation of non-functional and monofunctional materials, for example the monomer / initiator ratio, the ratio of the alcohol to the Lewis acid, the type of Lewis acid, the reaction temperature,

the solvent and the concentration.

  It is also preferable to use monosubstituted oxetanes at 3, ie "m" is preferably

  These are preferred because the homopolymerization of 335-disubstituted oxetanes gives crystalline polymers. By way of example, the polymerization of 3,3 bis (chloromethyl) oxetane gives.

  a crystalline polymer which melts at around 220 ° C.

  The hydroxyl-terminated prepolymers which are prepared from the preferred 3-monosubstituted oxetane monomers are amorphous oils which are preferably

  viscous materials which are easy to use. Prepoly-

  relatively pure, while those prepared from 3-disubstituted oxetane monomers contain large amounts of nonfunctional cyclic oligomers. In addition, the desired surface properties of the prepolymer can be obtained with only one fluorinated substituent at the position 3 of the oxetane type monomer, and a second fluorinated substituent does not contribute

  noticeably to the surface properties.

  In the examples which follow, the polymerization was carried out in butane-1,4-diol with a complex

  ether of boron trifluoride or a tetrahydro-

  furan and boron trifluoride The initiator was prepared from an ethereal complex of boron trifluoride

  of commercial quality that has been distilled before use.

  Similarly, butane-1,4-diol was distilled over calcium hydride and stored on a 0.4 nm molecular sieve prior to use. The polymerizations were conducted in a 100 ml glass flask which was equipped with a jacket and a mechanical stirrer. NMR analysis of the products was performed with a Bruker MSL-300 spectrometer at 300 MHz on a solution. in deuterochloroform by determining the proton and carbon displacements in ppm relative to tetramethylsilane and the displacements of fluorine relative to fluorotrichloromethane Infrared analysis was carried out by diffuse reflectance with a Nicolet SX-5 spectrometer on K Br The analysis thermal was performed

  The weight average molecular weights were determined using a Waters gel permeation chromatograph equipped with four columns (10 nm, 50 nm, 102 nm and 103 nm), a differential detector of refractive index and a Data Module 730.

EXAMPLE 1

  Preparation of 3- (2,2,2-trifluoroethoxymethyl)

  3-Methyloxetane A 50 weight percent dispersion (2.8 g, 58.3 mmol) of sodium hydride in the mineral oil is washed twice with hexanes and suspended in 35 ml of dimethylformamide. 5.2 g (52 mmol) of trifluoroethanol are added and the mixture is stirred for a minute. A solution of 10.0 g (39 mmol) of 3-hydroxymethyl-3-methyloxetane p-toluenesulfonate in ml of dimethylformamide is added. and the mixture is heated to 85 ° C. for 20 hours, after which time the 1 H NMR analysis of an aliquot shows that the sulfonate

departure was consumed.

  The mixture is poured into 100 ml of ice water and extracted with 2 volumes of methylene chloride. The combined organic extracts are washed twice with water, twice with a 2% by weight aqueous solution of hydrochloric acid, and brine, dried over magnesium sulfate and evaporated to leave 6.5 grams of 3- (2,2,2-trifluoroethoxymethyl) -3-methyloxetane as an oil containing less than 1 percent by weight of dimethylformamide. this product is 90 percent The oil is distilled at 30 C under a pressure of 26.7 Pa to give 4.3 g of analytically pure product, a yield of 60 percent The product analyzes are as follows:

  IR (K Br): 2960-2880, 1360-1080, 990, 840 cm-1.

  H-NMR: 1.33 (s, 2H), 3.86 (q, J = 8.8 Hz, 2H), 4.35

  (d, J = 5.6 Hz, 2H), 4.51 (d, J = 5.6 Hz, 2H).

  NMR 13 C: 20.72, 39.74, 68.38 (q, J = 40Hz), 77.63,

79, 41, 124 (q, J = 272 Hz).

  Elemental analysis: Calculated for C 7 H 11 F 302:

C = 45.65; H = 6.02; F = 30.95

  Found: C = 45.28; H = 5.83; F = 30.59.

EXAMPLE 2

  Preparation of 3,3-bis (2,2,2-trifluoroethoxymethyl) oxetane A 50 percent dispersion of sodium hydride (0.383 mol) in 18.4 g of mineral oil is washed twice with hexanes and placed in suspension in 200 ml of dimethylformamide. 38.3 g (0.383 mol) of trifluoroethanol are then added dropwise in 45 minutes while hydrogen gas escapes. The mixture is stirred for minutes and a solution is added. 30.0 g (0.073 mol) of 3,3-bis (hydroxymethyl) oxetane di-p-toluenesulfonate in 50 ml of dimethylformamide. The mixture is heated at 75 ° C. for 64 hours, at the end of which the analysis 1 H NMR of an aliquot shows that the sulfonate

departure was consumed.

  The mixture is poured into water and extracted with

  two volumes of methylene chloride

  The collected fractions are washed with brine, 2% aqueous solution of hydrochloric acid, and water, dried over magnesium sulphate and evaporated.

  to leave 17.5 g of 3,3-bis (2,2,2-trifluorethoxymethyl) -

  oxetane in the form of an oil containing less than 1 percent by weight of dimethylformamide The oil is purified by distillation in a bubble column between 42 and 48 ° C.

  a pressure of 1.35 k Pa to give 15.6 g of analytical ether.

  The analysis of the product is as follows: -1 IR (K Br): 2960-2800, 1360-1080, 995, 840 cm H NMR: 3.87 (s, 4) H), 3.87 (q, J = 8.8 Hz, 4H),

4.46 (s, 4H).

  13 C NMR: 43.69, 68.62 (q, J = 35 Hz), 73.15, 75.59, 123.87 (q, J = 275 Hz);

NMR 19 F: 74.6 (s).

  Elemental analysis: Calculated for C 9 H 12 F 603:

C, 38.31; H, 4.29; F = 40.40

  Found: C = 38.30; H, 4.30; F = 40.19.

EXAMPLE 3

  Preparation of 3- (2,2,3,3,4,4,4-heptafluorobutoxymethyl)

  3-methyloxetane A 50 weight percent dispersion of sodium hydride (6.1 g, 127 mmol) in the mineral oil is washed twice with hexanes and suspended in 60 ml of dimethylformamide. 0 g (120 mmol) of 2,2,3,3,4,4,4-heptafluorobutane-1-ol and the mixture is stirred for 45 minutes A solution of 25.0 g (97.5 mmol) is added of 3-hydroxymethyl p-toluenesulfonate in 1 ml of dimethylformamide and the mixture is heated to 85 ° C. for 30 hours, after which time the 1 H NMR analysis of an aliquot shows that the sulfonate of

departure was consumed.

  The mixture is poured into 100 ml of ice-cold water and extracted with two volumes of methylene chloride. The combined organic extracts are washed twice with water, twice with a 2% aqueous solution by weight of hydrochloric acid. and brine, dried over magnesium sulphate and evaporated to leave 27.5 g of 3- (2,2,3,3,4,4,4-heptafluorobutoxyethyl) -3-methyloxetane as an oil. oil is distilled at 33 C under

  a pressure of 26.7 Pa to give 12.2 g of analytical ether.

  The experimental analyzes are: -1 IR (K Br): 2960-2880, 1280-1030, 995, 840 cm H NMR: 1.31 (s, 3 H), 3 , 67 (s, 2H), 3.99 (t, J = 13.3 Hz, 2H), 4.34 (d, J = 5.7 Hz, 2H),

4.50 (5.7 Hz, 2H).

  NMR of 3 C: 20.242 (q, J = 125 Hz), 39.627 (s), 67.778 (3 x 3, J = 145.1 Hz, J = 26.1 Hz), 77.730 (t, J = 142 Hz) , 79.110 (t, J = 150 Hz), 108.72 (3 x 4, J = 264 Hz, J = 36 Hz), 114.7 (3 x 3, J = 256 Hz, J = 30 Hz), , 58 (4 x 3,

J = 286.9 Hz, J = 33.7 Hz).

NMR 9 F: -81.4, -120.6, -128.1.

  Elemental analysis: Calculated for C 9 H 11 F 702:

C, 38.04; H = 3.90; F = 46.80

  Found: C = 38.03; H, 3.65; F = 46.59.

EXAMPLE 4

  Polymerization of 3- (2,2,2-trifluoroethoxymethyl) -

3-methyloxetane

  A solution of 34.3 mg (0.38 mmol) of butane-

  1,4-diol and 109.7 mg (0.77 mmol) of ethereal boron trifluoride complex in 4 g of methylene chloride is stirred at room temperature for 15 minutes under nitrogen in a dry polymerization flask. The solution is cooled to 1.5 C and a solution of 1.20 g is added

  (6,52 mmol) of 3- (2,2,2-trifluoroethoxymethyl) -3-methyl-

  oxetane in 1.3 g of methylene chloride The resulting solution is stirred at between 1 and 2 ° C. for 5 hours, at the end of which 1 H NMR analysis of an aliquot indicates that the starting oxetane has been consumed. The solution is warmed to room temperature and quenched with water The organic phase is washed with brine and

  a 2 percent by weight aqueous solution of chlorinated

  water, and evaporated to leave 1.053 g of poly-3- (2,2,2-

  trifluorethoxymethyl) -3-methyloxetan in the form of an oil, a yield of 88 percent. Polymer analyzes are: Differential scanning calorimetry (DSC): Tg -45 C, decomposition temperature above C. Permeation chromatography on gel (CPG) with THF:

  Molecular weight Mn = 7376, M = 7951, polydisperser

sity = 1.08.

Inherent viscosity = 0.008.

  Molecular weight based on 1 H NMR: 6300.

  H-NMR: 0.95 (s, 3H), 3.26 (m, 4H), 3.52 (2.2H),

3.84 (q, 2H).

  13 C NMR: 17.57, 42.09, 69.30 (q, J = 33Hz), 74.42,

, 90, 125.18 (q, J = 280 Hz).

EXAMPLE 5

  Preparation of 3,3-bis (2,2,2-trifluoroethoxymethyl) polyl

oxétannel

  A solution of 33.9 mg (0.378 mmol) of butane

  1,4-diol and 106.3 mg (0.75 mmol) of ethereal trifluoride boron complex in 3.8 g of methylene chloride is stirred at room temperature for 15 minutes under nitrogen in a dry polymerization flask. The solution is cooled to 1.5 ° C. and a solution of 1.88 g (6.67 mmol) of 3,3-bis (2,2,2-trifluorethoxymethyl) oxetane in 2.3 g of sodium chloride is added. The resulting solution is stirred at between 1 and 2 ° C. for 16 hours, after which time the 1 H NMR analysis of an aliquot shows that

  the starting oxetane was consumed.

  The solution is warmed to room temperature and quenched with water The organic phase is washed with brine and a 2 percent aqueous solution of acid

  hydrochloric acid, and evaporated to leave 1.62 g of

  bis (2,2,2-trifluoroethoxymethyl) oxethanel, ie a yield of 85%. The prepolymer is a waxy solid. The analyzes of the polymer are: CBD: Tg 54.88 C, mp 80.96 ° C (26.35 joules / gram) )

  the decomposition temperature is higher

above 210 C.

  GPC (THF): Molecular Weight Mn = 5321, Mp = 7804,

polydispersity = 1.47.

Inherent viscosity = 0.008.

  1H NMR: 1.60 (m), 2.46 (s), 3.36 (s, 4H), 3.58 (s,

4H), 3.79 (q, 4H).

  NMR 13 C: 45.49, 68.25 (q, J = 33 Hz), 69.20, 70.97,

123.81 (q, J = 280 Hz).

  EXAMPLE 6 Preparation of poly-3- (2,2,3,3,4,4,4-heptafluorobutoxy-

  methyl) -3-methyloxetane A solution of 34.7 mg (0.38 mmol) butane-1,4-diol and 109.7 mg (0.77 mmol) ethereal boron fluoride complex in 3.4 g The solution is cooled to 1.5 ° C and a solution of 2.00 g (7.08 mmol) of carbon dioxide is added at room temperature for 15 minutes under nitrogen in a dry polymerization flask. - (2,2,3,3,4,4,4-heptafluorobutoxymethyl) -3-methyloxetane in 3.3 g of methylene chloride The resulting solution is stirred at 1.2 ° C. for 4 hours, at which time the H NMR analysis of an aliquot portion shows that

  the starting oxetane was consumed.

  The solution is warmed to room temperature and quenched with water The organic phase is washed with brine and a 2 percent aqueous solution of acid

  hydrochloric acid, and evaporated to leave 1.65 g of poly-

  3- (2,2,3,3,4,4, 4-heptafluorobutoxymethyl) -3-methyloxetan, 83% yield The prepolymer is an oil and its analyzes are as follows: GPC (THF): Molecular weight Mn = 4066, Mp = 5439, polydispersity = 1.34; inherent viscosity = 0.054 This oil is extracted with methanol and dried to give 1.46 g of polymer, a yield of 72%, which shows the following analyzes:

CBD: Tv -45 C.

  GPC (THF): Molecular weight Mn = 4417, Mp = 5658,

polydispersity = 1.28.

Inherent viscosity = 0.056.

  Molecular weight based on 1 H NMR = 8718.

  1H NMR: 0.93 (s, 3H), 3.20 (m, 4H), 3.48 (s, 2H), 3.92 (q, J = 13.6 Hz, 2H); ); 3 C NMR: 16.14, 40.57, 67.37 (t, J = Hz), 72.89,

74.76.

EXAMPLE 7

  Preparation of 3- (2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecan

  fluoroctyloxymethyl) -3-methyloxetane A 50 weight percent dispersion of sodium hydride (4.0 g, 83 mmol) in mineral oil is washed with

  hexanes and suspended in 200 ml of dimethyl

  formamide A solution of 30 g of 2,2,3,3,4,4,5,5,6,6,7,7,8,8,8pentadecafluoroctane-1-ol (75 mmol) in 50 ml of dimethylformamide is added over a period of 3 hours and the resulting mixture is stirred at room temperature for one hour. Next, a solution of 9.3 g (77 mmol) of 3-chloromethyl-3-methyloxetane in 20 ml of dimethylformamide and The resulting mixture is heated at 75 ° C. for 16 hours. The mixture is cooled to room temperature and slowly poured into 1 liter of ice water and extracted with two volumes of Freon 113. The combined organic extracts are washed twice with water with 2% aqueous solution by weight of hydrochloric acid and once with brine, dried over magnesium sulphate, filtered and evaporated to leave 32 g of crude product. The crude product is distilled under reduced pressure to give 26 g. 5 g (73%) of 3- (2,2,3,3,

  4,4,5,5,6,6,7,7,8,8,8-pentadécafluoroctoxyméthyl) -3-methyl-

  analytically pure oxetane, an oil having a point

  boiling point 68 to 70 C / 213.3 Pa Experimental analyzes

  are: H NMR (CD C 13 / Freon 113): 4.49 and 4.37 (AB, J = 5.5 Hz, 4H), 4.00 (triplet, J = 13.2 Hz,

  2H), 3.70 (singlet, 2H) and 1.32 (sin-

gulet, 2H).

  NMR 13 C: 6 21.02, 40.33, 68.77 (triplet,

J = 146.2 Hz), 78.60 and 79.87.

  NMR 19 F: 6 -81.3 (3 F), -119.9 (2 F), -122.6 (2 F), -123.3 (2 F), -123.5 (2 F) , -123.9 (2 F) and

-126.8 (2 F).

  Elemental analysis: Calculated for C 13 H 11 F 1502:

C-32.2; H-2.3; F-58.9

Found: C, 32.2; H-2.2; F-58.3.

  EXAMPLE 8 Preparation of 3- (3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluorone)

  octyloxymethyl) -3-methyloxetane In a manner similar to that described above, 12.0 g (73 mmol) of 3-bromomethyl-3-methyl-

  oxetane with 26.5 g (72.7 mmol) of 3,3,4,4,5,5,6,6,7,7,

  8,8,8-tridecafluoroctane-1-ol in 300 ml of dimethyl

  formamide in the presence of 3.9 g of a 50 percent by weight dispersion of sodium hydride (81 mmol) in mineral oil at 85 ° C. for 24 hours to obtain 21.5 g.

  (yield: 70%) of 3- (3,3,4,4,5,5,6,6,7,7,8,8,8-trideca

  fluoroctyloxymethyl) -3-methyloxetane, a colorless oil

  having a boiling point of 66-68 ° C / 266.6-333.3 Pa.

  1 H NMR (CDCl 3): δ 4.50 and 4.36 (AB, J = 5.5 Hz, 4H), 3.78 (t, J = 6.6 Hz, 2H), 3.53. (s, 2H), 2.42 (triplet of triplets, J = 6.6 and 18 Hz, 2H)

and 1.31 (s, 3H).

  13 C NMR (CDCl 3): δ 79.89, 63.31, 39.9, 31.64 (t) and 21.1 (the signals generated by the carbon atoms carrying fluorine are not included in causes complex duplication profiles and overlapping signals).

  NMR 19 F: 6 -81.4 (3 F), -113.8 (2 F), -118.2 (2 F), -122.3 (2 F), -123.3 (2 F) , -124.1 (2 F) and

-126.7 (2 F)

  Elemental analysis: Calculated for C 13 H 13 F 1302

C = 34.8; H = 2.9; F = 55.1

  Found: C = 35.1; H = 3.0; F = 54.7.

  EXAMPLE 9 Purification of commercial fluorinated alcohols Zonyl BA-L is an oligomeric mixture of narrowly distributed fluorinated alcohols, which is available from

  Dupont Chemicals in quantities at a plant scale

  Zonyl BA-L is a yellow liquid which, according to gas-liquid chromatography, is a mixture of oligomers

  following mothers: 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-octan-1-ol (C 8, 60%); 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,10-heptadecafluorodecan-1-ol (C 10.26%); 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12henéicosafluorododecanol (C 12.6%) ; and various unidentified high-boiling compounds (8%) Zonyl BA-L is washed with equal volumes of a 10 percent by weight aqueous solution of sodium thiosulfate, a 10 percent aqueous solution by weight of sodium bicarbonate (to remove HF), water and brine, dried, filtered and distilled under reduced pressure (400 Pa) between 50 and 100 ° C to give a mixture of 69% C 8, 26% of C 10 and 5% of

C 12 in a yield of 83%.

EXAMPLE 10

  Preparation of a mixture of 3,3,4,4,5,5,6,6,7,7,8,8,8-

  tridecafluoroctyloxymethyl-, 3,3,4,4,5,5,6,6,7,7,8,8, 9,9,10,10,10heptadecafluorodecyloxymethyl and

  3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10,11,11,12,12,12-

  heneicosafluorododecyloxymethyl-3-methyloxetanes In a manner similar to that described above, 51.6 g (129 mmol) of a mixture of fluorinated alcohols containing 69% of C 8, 26% of C 10 and 5 are reacted. % C 12 with 27 g of 3-iodomethyl-3-methyloxetane (127 mmol) in 500 ml of dimethylformamide at 85 ° C. for 18 hours to obtain 60 g

  of raw product The gross product is distilled

  Fractionated fraction in a 15.2 cm Vigreux column to give the following fractions: The fraction N 1 (4.8 g) is collected between 25 ° C. and 45 ° C. under 467-387 Pa.

  and it is a mixture of unreacted fluorinated alcohols.

  The fraction N 2 (2.8 g) is collected between 45 and 71 ° C. under 93.3-400 Pa and is a mixture of fluorinated alcohols

  unreacted and fluorinated oxetane monomers.

  The last fraction (49 g, 80%), boiling between 70 and C under 93.3120 Pa is a 73% mixture of 3,3,4,4, 5,5,6,6,7,7,8, 8,8-tridecafluoroctyloxymethyl-3-methyl-oxetane (C 8 -oxetan), 24% of 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10 10-heptadecafluorodecyloxymethyl-3-methyloxetane (C 10 -oxetane) and 3% 3,3,4,4,5,5,6,6,7,7,8,8,9,9,10,10.

  11,11,12,12,12-henéicosafluorododécyloxyméthyl-3-methyl-

  oxetane (C 12 -oxetane), a colorless oil having a boiling point of 70 to 85 ° C at 93.3-120 Pa.

  NMR 1 H NMR 13 C NMR 9 F (CDCl 3): δ 4.50 and 4.35 (AB, J = 5.9 Hz, 4H), 3.78 (t, J = 6.6 Hz, 2H), 3.53 (s, 2H), 2.42

  (tt, J = 6.6 and 17.6 Hz, 2H) and 1.31 (s, 3H).

  : 21.3, 31.86 (t, J = 130.1 Hz), 40.2, 63.6, 76.8 and 80.2 (the signals generated by fluorine-bearing carbon atoms are not included because of complex overlap profiles and overlap

signals).

  : -81.5, -113.8, -122.3, -123.3, -124.1,

-124.5, -125.8 and -126.7.

EXAMPLE 11

  Preparation of 3,3-bis (2,2,3,3,4,4,4-heptafluorobutoxy-

  methyl) oxetane In a manner similar to that described above,

  155 g (1 mole) of 3,3-bis (chloromethyl) are reacted.

  oxetane with 402 g (2.01 moles) of 2,2,3,3,4,4,4-hepta-

  fluorobutane-1-ol in two liters of dimethylformamide in the presence of 100 g of a 50 percent by weight dispersion of sodium hydride in mineral oil (2.3 moles) at 85 C for 16 hours to obtain 340 g (yield: 70%) of 3,3-bis (2,2,3,3,4,4,4heptafluorobutoxymethyl) oxetane, a

  Clear, colorless liquid Analysis by gas chromatography

  liquid reveals that the purity of this material is superior

  at 99%, with a boiling point of 70-72 C / 133-173 Pa.

  H-NMR (CDCl3): δ 4.44 (s, 4H), 3.97 (t, J = 13.2Hz,

4H), 3.86 (s, 4H).

  NMR 13 C: 6 43.9, 68.1 (t), 73.5 and 75.6 (the signals

* generated by the carbon atoms

  fluorine are not included because of the complex

overlapping signals).

  NMR 19 F: 6 -81.6 (3 F), -121.0 (2 F) and -128.3 (2 F).

  Elemental analysis: Calculated for C 13 H 12 F 1403:

C = 32.4; H = 2.5

Found: C = 32.3; H = 2.3.

I 1

EXAMPLE 12

  Preparation of 3,3-bis (2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-

  pentadecafluoroctyloxymethyl) oxetane In a manner similar to that described above, 15.5 g (0.1 mol) of 3,3 bis (chloromethyl) oxetane are reacted with 84 g (0.21 mol) of 2.2 , 3,3,4,4,5,5,6, 6,7,7,

  8,8,8-pentadecafluoroctane-1-ol in 300 ml of dimethyl

  formamide in the presence of 10.0 g of a 50 percent by weight dispersion of sodium hydride in mineral oil (0.23 mole) at 85 C for 32 hours to obtain 58 g

  (yield: 66%) of 3,3-bis (2,2,3,3,4,4,4-heptadecafluor-

  octyloxymethyl) oxetane in the form of a colorless liquid

  clear An analytical sample is prepared by chromato-

  on silica gel column using methylene chloride as eluent The boiling point of the liquid is 130-135 ° C / 133-160 Pa The analyzes are: 1 H NMR (CD C 13): 6 4.44 (s, 4H), 3.96 (t, J = 13.4 Hz,

4H), 3.88 (s, 4H).

  NMR 13 C: 6 44.2, 68.7 (t), 73.9 and 76.5 (the signals

  generated by the carbon atoms

  fluorine are not included because of the complex

overlapping signals).

  NMR 19 F: 6 -81.5 (6F), -119.7 (4F), -121.5 (4F),

  -122.6 (8 F), -123.3 (4 F) and -126.8 (4 F).

  Elemental analysis: Calculated for C 21 H 12 F 3003:

C = 28.6; H = 1.4; F = 64.6

Found: C = 28.2; H = 1.5.

  EXAMPLE 13 Copolymerization of 3- (2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-

  pentadecafluoroctyloxymethyl) -3-methyloxetane with 3- (2,2,2-trifluorethoxymethyl) -3-methyloxetane A one-liter round-bottom three-necked flask is equipped with a mechanical stirrer, nitrogen inlet / outlet tubes, A reflux condenser, a thermometer and an ampoule for constant addition The apparatus is dried by means of a hot air gun, cooled under nitrogen to room temperature and charged with a mixture of 0.914 g ( 6,52 mmol) of trimethylolpropane, 3.1 g (22 mmol) of complex of tetrahydrofuran and boron trifluoride, ml of 1,1,2-trichlorotrifluoroethane and 30 ml of anhydrous methylene chloride. The mixture is stirred at room temperature. 30 minutes, cooled to 10 ° C. and then treated dropwise with a solution of 106 g (576 mmol) of 3- (2,2,2-trifluoroethoxymethyl) -3-methyloxetane and 94 g.

  (195.2 mmol) of 3- (2,2,3,3,4,4,5,5,6,6,7,7,8,8,8-pentadecan)

  fluoroctyloxymethyl) -3-methyloxetane in 40 ml of 1,1,2-

  trichlorotrifluoroethane A moderate evolution of heat is observed during the addition of the monomer. The reaction temperature is maintained at 18 ° C. throughout the addition.

  and the progress of the reaction is monitored by NMR analysis.

  The mixture is stirred at 18 ° C. for 2 hours and then at 25 ° C. for 4 hours, at which time the NMR analysis of an aliquot indicates that 98 per cent of the oxetane type monomers have been consumed. The reaction mixture is diluted.

  with 50 ml of methylene chloride and 50 ml of 1,1,2-tri-

  chlorotrifluoroethane and quenched with 50 ml of water The organic phase is separated, washed with two equal volumes of water and added dropwise to a quantity of methanol in

  excess of 10 times at room temperature Precise oil

  The solvent was separated and redissolved in a 50:50 mixture of methylene chloride and 1,1,2-trichlorotrifluoroethane and transferred to a 500 ml round bottom flask. The solvent was evaporated under reduced pressure and the resulting oil was dehydrated at room temperature. The NMR analyzes of this material show that it is a random copolymer of the two above-mentioned monomers in the form of a clear colorless viscous oil, a yield of 85 percent. a ratio of 74:26 The analyzes of the polymer are:

CBD TV = -40 C.

  GPC (THF, polystyrene standard): number average molecular weight = 6178; average molecular weight in

  weight = 7286; polydispersity = 1.18.

  Number average molecular weight

NMR H = 7040.

Functionality = 3.

  Inherent viscosity = 0.065; 1 H NMR (CDCl 3): δ 0.94 (s, -CH 3), 3.23 (m, -CH 2 of the backbone), 3.47 (s, -CH 2 O), 3.75 ( q, J = 8.6 Hz, -CH 2 CF 3) and 3.85 (t, J = 13.5 Hz,

1-CH 2 C 3 F 7).

  1 H NMR (CDCl 3 / trifluoroacetic anhydride): δ 1.00 (s, -CH 3), 3.37 (m, -CH 2 of the backbone), 3.49 (s, -CH 2 O) , 3.78 (q, J = 8.6 Hz, -CH 2 CF 3), 3.96 (t, J = 13.5 Hz, -CH 2 C 3 F 7) and

4.30 (s, CH 3 COCF 3).

  C NMR (CDCl 3): δ 17.1, 41.2, 41.3, 68.5 (t),

68.9 (q), 73.7, 75.3 and 75.5.

  In a manner similar to that described above, random copolymers of the above monomers are also prepared in ratios of 50:50, 33:67, 25:75 and 10:90. These copolymers are clear colorless oils which are soluble in a solvent mixture consisting of

  methylene chloride and 1,1,2-trichlorotrifluoroethane.

  EXAMPLE 14 Copolymerization of 3- (2,2,2-trifluoroethoxymethyl)

  3-methyloxetane with 3- (2,2,3,3,4,4,4-heptafluorobutoxymethyl) 3-methyloxetane

  In a manner similar to that described in Example 13, a solution of 35 g (190 mmol) of 3- (2,2,2-tri-

  fluorethoxymethyl) -3-methyloxetane and 183 g (644 mmol) of 3- (2,2,3,4,4,4,4-heptafluorobutoxymethyl) -3-methyloxetane in 50 ml of 1,1,2-trichlorotrifluoroethane is added to a mixture of 0.390 g (4.33 mmol) of 1,4-butanediol, 1.55 g (11.1 mmol) of tetrahydrofuran-boron trifluoride complex and 100 ml of methylene chloride

  at 18 ° C. The mixture is stirred at 18 ° C. for 3 hours,

  The solution was stirred with water and precipitated in methanol to give, after drying at 85 ° C./267 Pa for 16 hours, 186 g of a clear colorless oil, a yield of 85 percent. NMR analysis reveals that this material is a copolymer

  at 22:78 of the two monomers above.

The polymer analyzes are

CBD: Tg = -42 C.

  GPC (THF, polystyrene standard): number average molecular weight = 15,660; average molecular weight

  by weight = 30,640; polydispersity = 1.96.

  Number average molecular weight

NMR H = 18,400.

Functionality = 2.

Inherent viscosity = 0.071.

  1 H NMR (CD C 13 / Freon 113): δ 0.91 (s, CH 3), 3.22 (m, -CH 2 of the backbone), 3.44 (s, -CH 2 O), 3.79 (q, J = 8.8 Hz, -CH 2 CF 3) and 3.86 (t,

J = 13.5 Hz, -CH 2 C 3 F 7).

  1 H NMR (CD C 13 / Freon 113 / trifluoroacetic anhydride): δ 0.95 (s, -CH 3), 3.23 (m, -CH 2 of the backbone), 3.46 (s, -CH 2 O), 3.77 (q, J = 8.6 Hz, CH 2 CF 3), 3.87 (t, J = 13.5 Hz, -CH 2 C 3 F 7) and 4.31

(s, CH 2 COCF 3).

  13 C NMR (CD C 13 / Freon 113): δ 17.3, 41.6, 41.8, 68.6 (t), 69.3 (q), 74.2, 75.6 and 75, 9 (signals generated by fluorine-bearing carbon atoms are not included). In a similar manner, random copolymers of the above monomers are also prepared at

  50:50 and 75:25 ratios. The copolymers are clear colorless oils which are soluble in tetrahydrofuran, methylene chloride and 1,1,2-trichloroethane.

trifluoroethane (Freon 113).

EXAMPLE 15

  Polymerization of 3- (3,3,4,4,5,5,6,6,7,7,8,8,8-

  tridecafluoroctyloxymethyl) -3-methyloxetan In a manner similar to that described in Example 13, a solution of 10 g (22.3 mmol) of 3- (3,3,4,4,5,5,6,6 , 7,7,8,8,8-tridecafluoroctyloxymethyl) -3-methyloxethane in 3 ml of Freon 113 is added dropwise to a mixture of 109 mg (0.78 mmol) of tetrahydrofuran complex and boron trifluoride and 35 mg ( 0.39 mmol) of 1,4-butanediol in methylene chloride at 10 ° C. The mixture is stirred at room temperature for 24 hours, quenched with water and precipitated in methanol to give, after drying at 80 ° C. 267 Pa for 16 hours, 8, 3 g of 3- (3,3,4,4,5,5, 6,6,7,7,8,8,8-tridecafluoroctyloxymethyl) -3-methyloxetane, a clear, colorless oil. Polymer analyzes are:

  Inherent viscosity (THF / 30 C) = 0.067 dl / g.

  GPC: Mn = 5340, Mp = 6620, polydispersity = 1.24.

CBD: T = -38 C;

  H NMR (CD C 13 / Freon 113): 6.667 (t, 5.9 Hz, 2H), 3.31 (s, 2H), 3.21 (m, 4H), 2, 35 (m, 2H)

and 0.93 (s, 3H).

  1 H NMR (CD C 13 / Freon 113):? 0.95 (s, 3H), 2.37 (broad t, J = 18.3 Hz, 2H), 3.25 (m, 4H)? ), 3.35 (s, 2H), 3.71 (t, 6.0 Hz, 2H) and 4.30

(AB, -CH 2 OCOCF 3).

  Number average molecular weight

the NMR of H = 4756.

  NMR of 13 C (CD C 13 / Freon 113): δ 17.35, 31.75 (t), 41.5,

63.4, 74.1 and 74.3.

  EXAMPLE 16 Copolymerization of a mixture of 3,3,4,4,5,5,6,6,7,7,8,8,8-

  tridecafluoroctyloxymethyl-, 3,3,4,4,5,5,6,6,7,7,8,8,9,9, 10,10,10heptadecafluorodecyloxymethyl and 3,3,4,4,5,5,6 , 6

  7,7,8,8,9,9,10,10,11,11,12,12,12-henéicosafluorododécyloxy-

methyl-3-méthyloxétannes

  In a manner similar to that described in

  13, a solution of 30 g (62 mmol) of C 8 (73%), C 10 (24%) and C 12 (3%) oxetane monomers in 10 ml of Freon 113 is added dropwise to a mixture of 300 mg

  (2.14 mmol) of tetrahydrofuran and trifluoromethyl

  of boron and 95 mg (1.05 mmol) of 1,4-butanediol in 30 ml of methylene chloride at 10 ° C. The mixture is stirred at room temperature for 24 hours, quenched with water and precipitated in methanol. to give, after drying at 80 ° C. / 267 Pa for 16 hours, 24 g of the title copolymer, ie a yield of 80 percent. The copolymer is a viscous colorless oil. The copolymer analysis is:

Inherent viscosity = 0.075 dl / g.

  GPC: Mn = 6639, Mp = 9368; polydispersity = 1.41.

  1 H NMR (CD C 13 / Freon 113):? 0.95 (s, 3H), 2.37 (broad t, J = 18.3 Hz, 2H), 3.25 (m, 4H)? , 3.35 (s, 2H), 3.71 (t, 6.0 Hz, 2H) and 4.30

(AB, -CH 2 OCOCF 3).

  Number average molecular weight

NMR of H = 5021.

  NMR 13 C (CD C 13 / Freon 113): δ 17.35, 31.75 (t), 41.1,

41.5, 63.4, 74.1 and 74.3.

EXAMPLE 17

  Polymerization of 3,3-bis (2,2,3,3,4,4,4-heptafluorobutoxy-

  In a manner similar to that described in Example 13, a solution of 252 g (523 mmol) of 3,3-bis (2,2,3,3,4,4,4-heptafluorobutoxymethyl) oxetane in 75 ml of Freon 113 is added to a mixture of 1.05 g (7.5 mmol) of tetrahydrofuran-boron trifluoride complex and 0.265 g (2.93 mmol) of 1,4-butanediol in The mixture is stirred at room temperature for 48 hours, after which time the NMR analysis of an aliquot indicates 96 percent conversion. The reaction mixture is quenched with water and carbon dioxide. polymer is precipitated in methanol to give, after drying at 80 C / 267 Pa for 16 hours,

  211 g of poly-3,3-bis (2,2,3,3,4,4,4-heptafluorobutoxy-

  Methyl) Oxetane, a colorless oil, in 84 percent yield GPC analysis of this oil reveals that it is a blend of 68% linear product and 32% cyclic product The cyclic product is isolated and identified as the cyclic tetramer, a white waxy solid

having a melting point of 80 C.

  1H NMR: δ 3.87 (t, J = 13.5 Hz, 4H), 3.54 (s, 4H) and 3.32 (s, 4H) (no groups were observed).

  terminals by the addition of tri-

  fluoroacetic). NMR of 13 C: 6 71.2, 68.6, 68.4 (t) and 46.2 (the signals

  generated by the carbon atoms

both fluoride are not included).

  The above oil is further purified by first dissolving the material in methylene chloride / Freon 113 (75:25), precipitating the polymer in methanol in excess of 10 times, stirring the precipitated oil. with tetrahydrofuran at room temperature for 2 days, and finally separating and drying the insoluble fraction at 85 ° C. under 267 Pa for 16 hours. 128 g of a clear viscous oil are thus obtained, giving an overall yield of 51%. GPC analysis of this oil reveals that it is a mixture of 91% linear polymer and 9% cyclic tetramer The analyzes of the polymer are: CBD: Tv = 43

  GPC: Mn = 5526, Mp = 7336, polydispersity = 1.32.

  1 H NMR (CD C 13 / Freon 113 / trifluoroacetic anhydride): 6.339 (s, 4H), 3.59 (s, 4H), 3.87 (t,

  J = 13.5 Hz, 4H) and 4.40 (s, -CH 2 OCOCF 3).

  Number average molecular weight

the NMR of H = 5200.

  13 C NMR (CD 13 C / Freon 113): 46.4, 68.5 (t), 70.1 and 72.1 (the signals generated by fluorine-bearing carbon atoms are not included).

Claims (37)

  A hydroxyl-terminated prepolymer, characterized in that it has the structure: ## STR1 ## where n is 1 to 1 5; m is 1 or 2; R is hydrogen or an alkyl group having 1 to 4 carbon atoms; R 1 is an alkylene or isoalkylene group having 2 to about 5 carbon atoms;   Rf is an alkyl, isoalkyl, halogeno   alkyl, linear or branched chain perfluorinated halogenisoalkyl having 1 to 20 carbon atoms, or an oxa-perfluorinated polyether having 4 to about 60 carbon atoms; and x is from 2 to about 250.   Hydroxyl-terminated prepolymer according to Claim 1, characterized in that m is 2 and N is 1.   Hydroxyl-terminated prepolymer according to claim 2, characterized in that Rf is the trifluoromethyl group.   Hydroxyl-terminated prepolymer according to claim 2, characterized in that Rf is the heptafluoropropyl group.   Hydroxyl terminated prepolymer according to Claim 2, characterized in that Rf is the pentadecafluoroheptyl group.   Hydroxyl-terminated prepolymer according to claim 1, characterized in that m is 1 and n is 1.   Hydroxyl-terminated prepolymer according to claim 6, characterized in that Rf is the trifluoromethyl group.   Hydroxyl-terminated prepolymer according to Claim 6, characterized in that Rf is the heptafluoropropyl group.   Hydroxyl-terminated prepolymer according to claim 6, characterized in that Rf is the pentadecafluoroheptyl group.   Hydroxyl terminated prepolymer according to claim 1, characterized in that m is 1 and n is 2.   Hydroxyl terminated prepolymer according to claim 10, characterized in that Rf is the tridecafluorohexyl group.   Hydroxyl terminated prepolymer according to claim 10, characterized in that Rf is the heptadecafluoroctyl group.   Hydroxyl terminated prepolymer according to claim 10, characterized in that Rf is the henicosafluorodecyl group.   A hydroxyl terminated prepolymer, characterized in that it has a molecular weight of from 1000 to about 30,000 and a polymer backbone resulting from the oxetane ring opening of oxetane monomers substituted at the position of the carbon 3 by one or two fluorinated alkoxymethyl groups of the formula: CH 2 (CH 2) n Rf where n is 1 or 2; and Rf is an alkyl, isoalkyl, haloalkyl, straight-chain perfluorinated haloalkyl group or   branched having 1 to 20 carbon atoms, or an oxa-perfluorinated polyether having 4 to about 60 carbon atoms.   Hydroxyl terminated prepolymer   according to claim 14, characterized in that N is 2.   The hydroxyl terminated prepolymer according to Claim 15, characterized in that Rf is the tridecafluorohexyl group. Hydroxyl terminated prepolymer according to Claim 15, characterized in that Rf is the heptadecafluoroctyl group.   The hydroxyl terminated prepolymer according to claim 17, characterized in that said polymer backbone is a copolymer of two or three   Oxetane type monomers having different Rf groups.   Hydroxyl terminated prepolymer according to claim 15, characterized in that Rf is the henicosafluorodecyl group.   A hydroxyl terminated prepolymer according to claim 19, characterized in that said polymer backbone is a copolymer of two or three   Oxetane type monomers having different Rf groups.   21 Hydroxyl terminated prepolymer   according to claim 14, characterized in that N is 1.   Hydroxyl terminated prepolymer according to claim 21, characterized in that Rf is the trifluoromethyl group.   The hydroxyl terminated prepolymer according to claim 22, characterized in that said polymer backbone is a copolymer of two or three   Oxetane type monomers having different Rf groups.   The hydroxyl terminated prepolymer according to claim 22, characterized in that said oxetane type monomer comprises two of said alkoxymethyl groups at said carbon 3 position. Hydroxyl terminated prepolymer according to claim 21, characterized in that Rf is the heptafluoropropyl group.   The hydroxyl terminated prepolymer according to claim 25, characterized in that said polymer backbone is a copolymer of two or three   Oxetane type monomers having different Rf groups.   A hydroxyl terminated prepolymer according to claim 25, characterized in that said oxetane monomer comprises two of said groups   alkoxymethyl at said carbon position 3.   Hydroxyl terminated prepolymer according to claim 21, characterized in that Rf is the pentadecafluoroheptyl group.   The hydroxyl terminated prepolymer according to claim 25, characterized in that said polymer backbone is a copolymer of two or three   Oxetane type monomers having different Rf groups.   Oxetane-type monomer with fluorinated alkoxy chain, characterized in that it corresponds to the formula: R 2; CH 2 O (CH 2) n Rf 1 m CH 2   Where: n is 1 to 5; m is 1 or 2; R is hydrogen or an alkyl group having 1 to 4 carbon atoms; and Rf is an alkyl, isoalkyl, haloalkyl, linear or branched chain perfluorinated halogenisoalkyl group having 1 to 20 carbon atoms, or an oxa-perfluorinated polyether having 4 to about carbon atoms.   31 fluorinated alkoxy-chain oxetane monomer according to claim 30, characterized in that Rf is a perfluorinated alkyl group.   32 fluorinated alkoxy oxetane type monomer according to claim 31, characterized in that m is 2 and n is 1.   A fluorinated alkoxy-chain oxetane monomer according to claim 31, characterized in that Rf is the trifluoromethyl group.   34 fluorinated alkoxy-chain oxetane monomer according to claim 31, characterized in that Rf is the heptafluoropropyl group.   A fluorinated alkoxy-chain oxetane monomer according to claim 31, characterized in that Rf is the pentadecafluoroheptyl group.   Alkoxy fluorinated oxetane type monomer according to claim 31, characterized in that m is 1 and N is 1.   Alkoxy fluorinated oxetane type monomer according to claim 35, characterized in that Rf is the trifluoromethyl group.   A fluorinated alkoxy-chain oxetane monomer according to claim 35, characterized in that Rf is the heptafluoropropyl group.   A fluorinated alkoxy-chain oxetane monomer according to claim 35, characterized in that Rf is the pentadecafluoroheptyl group.   A fluorinated alkoxy oxetane type monomer according to claim 31, characterized in that m is 1 and n is 2.   Alkoxy fluorinated oxetane type monomer according to claim 39, characterized in that Rf is the tridecafluorohexyl group.   A fluorinated alkoxy oxetane type monomer according to claim 39, characterized in that Rf is the heptadecafluoroctyl group.   A fluorinated alkoxy oxetane type monomer according to claim 39, characterized in that Rf is the henicosafluorodecyl group.