MXPA99006791A - Grafting of polymers with fluorocarbon compounds - Google Patents

Abstract

Fluorine containing terminal olefins may be grafted onto polymers containing hydrogen bound to carbon in the presence of free radicals. The olefins may also contain other functional groups. The resulting novel grafted polymers are useful as molding resins, for coating and as catalysts.

Description

GRAFTING OF POLYMERS WITH FLUOROCARBURO COMPOUNDS FIELD OF THE INVENTION The fluorine-containing defines can be grafted onto polymers containing carbon-hydrogen bonds in the presence of a source of free radicals. The resulting grafted polymers have unique structures, and can be used as catalysts.

TECHNICAL BACKGROUND Organic polymers that contain fluorine substitution have traditionally been made (co) polymerizing one or more fluorine-containing monomers, optionally with non-fluorinated monomers. It is well known that polymers containing large amounts of fluorine often have desirable properties, such as improved thermal and / or chemical resistance. However, polymers containing only relatively small amounts of fluorine also often have desirable properties (compared to non-fluorinated polymers), such as altered surface properties or are useful as REF .: 30544 catalysts. Therefore, versatile and economical methods for making polymers with relatively low fluorine contents are desirable.

BRIEF DESCRIPTION OF THE INVENTION This invention relates to a process for producing a partially fluorinated polymer, comprising contacting in liquid phase a first polymer containing hydrogen bonded to carbon with a compound of the formula H2C = CHCR1R R6Y, and a source of free radicals, in wherein: R1 and R2 are each independently fluorine or perfluoroalkyl containing from 1 to 20 carbon atoms; R6 is fluorinated alkylene containing 1 to 20 carbon atoms and which optionally contains one or more ether or alkylene groups containing from 1 to carbon atoms and which optionally contains one or more ether groups; and Y is hydrogen or a functional group; and with the condition that the contact is made at a temperature at which the source of free radicals generates free radicals.

This invention also relates to a polymer comprising branches containing the formula -CH2-CH2-CR1R2R6Y, wherein: R1 and R2 are each independently fluorine or perfluoroalkyl containing from 1 to 20 carbon atoms; Rb is fluorinated alkylene containing 1 to 20 carbon atoms and optionally containing one or more ether or alkylene groups containing from 1 to 20 carbon atoms and optionally containing one or more ether groups; and Y is hydrogen or a functional group; and with the proviso that a polymer backbone contains hydrogen bound to carbon.

DETAILS OF THE INVENTION Certain terms are used herein, and are defined as follows: "Fluorinated alkylene" means an alkylene group containing one or more fluorine atoms. By a "functional group" is meant any univalent group, defined in R. T.

Morrison, et al., Organic Chemistry, 6th Ed., Prentice Hall, Englewood Cliffs. NJ. 1992, p. 167-168, and is an atom or group of atoms that defines the structure of a particular family of organic compounds and, at the same time, determines (at least partially) their properties. Any functional group present should not interfere with any contemplated reaction such as the graft described above, nor should it result in any compound in which it is present being uselessly unstable. By "graft in the present" is meant the union of a branch to a pre-existing polymer. In the present a branching will usually be monomeric, ie it contains only one of the graft molecules. By a "free radical source" is meant any compound or other means of generating free radicals such as ionizing radiation. If the free radicals are thermally generated, then the grafting reaction is carried out at temperatures at which the source of free radicals reacts to form free radicals. By "containing one or more ether groups" is meant to contain one or more ether oxygen atoms between alkylene segments.

By "hydrocarbyls" is meant a univalent group containing only carbon and hydrogen. By "substituted hydrocarbyl" is meant a hydrocarbyl group containing one or more functional groups. The grafting process described herein is carried out in the liquid phase. This means that all the ingredients are in the liquid phase at the time of the grafting reaction. However, this does not mean that all the ingredients must be in the same liquid phase, nor does it mean that any additional liquid must be present (such as a "solvent") during the process. The polymer itself and / or the fluorinated compound to be grafted may be liquids and liquefy the other components. If a chemical source of free radicals is used, it can also be a liquid or dissolve in one of the other components, but will often be present in relatively small amounts, and thus be unable to dissolve the other components. Useful Y groups include -S02F, -C02R3, P (0) (0RJ) 2, S03H, SO3M and -S (0) 2NHS (O) ZR4, wherein each of R3 is independently hydrocarbyl or substituted hydrocarbyl containing 1 to 20 carbon atoms, and R 4 is perfluoroalkyl containing from 1 to 20 carbon atoms. In a preferred compound or polymer, Y is halogen, more preferably fluorine; sulfonyl fluoride; sulfonic acid; or hydrogen. Preferred R groups are perfluoro-alkylene or perfluoroalkylene substituted with ether, and especially preferably - (CF2) d- wherein d is from 2 to 20 and -CF20CF2CF2-. Sources of free radicals are well known in the art, see for example J. Brandrup, et al., Ed., Polymer Handbook, 3rd Ed., John Wiley & Sons. New York, 1989, p. II-1 to 11-65 and H. Mark, et al., Ed., Encyclopedia of Polymer Science and Engineering, vol. 13, John Wiley & Sons, New York, 1988, p. 754-789 both of which are included herein by reference. These "sources" can be chemical compounds such as peroxides or other means to generate free radicals, such as ionizing radiation. More commonly chemical compounds that are sources of free radicals will be used. These compounds can form free radicals by any method, for example by thermally decomposing them to form free radicals, or by the reaction of a redox couple to form free radicals. The thermal decomposition of a source of free radicals is a preferred method for forming free radicals. Useful sources of free radicals include compounds such as t-butyl peroxide and benzoyl peroxide. If a compound is used as a source of free radicals, usually relatively small amounts are used, typically from about 0.1 to about 25 mole percent, preferably about 1 to 10 mole percent, of the graft molecule present. The amount of graft molecule, H2C = CHCR1R2R6Y, grafted on the polymer vary according to the amount of H2C = CHCR1R2R6Y relative to the polymer, the amount of free radical sources present, and the efficiency of the grafting process. It is preferred that about 1 to about 5000 g, more preferably from about 500 g to about 2000 g, of graft molecule per kg of ungrafted (starting) polymer is currently grafted onto the polymer. In another preferred process and its resulting polymer, the grafted polymer has more hydrogen atoms than fluorine atoms, more preferably the ratio of hydrogen atoms to fluorine atoms is about 3 or more, especially preferably about 5 to about 150. .

The polymers that can be grafted in the process described herein, that is to say they are suitable, are those that do not undergo as much decomposition, typically decrease in molecular weight, in the presence of free radicals, as to return to the final non-usable product. It is well known in the art, see for example H. Mark, et al., Ed., Encyclopedia of Polymer Science and Engineering, vol. 13, John Wiley &; Sons, New York, 1988, p. 667-682, that some polymers are relatively stable in the presence of free radicals, while others may undergo relatively rapid chain division and molecular weight decrease. For example linear polyethylene is thought to be relatively stable, while most polypropylenes are thought to be relatively unstable. However, even "relatively unstable" polymers can be grafted under some circumstances. For example, when it is desired to graft only a small amount of H2C = CHCR1R2R6Y onto the polymer, only small amounts of the free radical source, and the resultant loss of molecular weight (if any) in the polymer that is being used, may be necessary. grafted may be acceptable in the intended application. Exposure to free radicals can also crosslink some polymers, depending on the conditions. A situation such as this may also be acceptable, since the crosslinked polymers may also be desired. For example, if used as a catalyst, the insolubility of a cross-linked polymer can be an advantage in recovering the polymer after use. Effectively in the process described herein a crosslinked polymer can be used as the starting polymer. In this case it may be desirable to dilate the crosslinked polymer with another compound or with H2C = CHCRiR2R6Y and / or the source of free radicals, to obtain a more uniform graft. Preferred polymers for grafting include polyethylene, especially (relatively) linear polyethylene, polyethers such as poly (tetramethylene ether) glycol, and ethylene copolymers such as ethylene / vinyl acetate copolymer and ethylene / methyl acrylate copolymer . Reactions may be made on the grafted polymer after the grafting reaction. For example, the functional groups grafted onto the polymer can be transformed into other functional groups. The grafted polymers described herein can be used as molding resins, in coatings, or be used to form films. They can be mixed with other polymers to modify those other characteristics of the polymers, such as surface properties. Grafted polymers containing functional groups may be useful as catalysts, see for example Experiment 4. In the Examples and Experiments, the following abbreviations are used: 3-Me-THF-3-methyltetrahydrofuran DSC - differential scanning calorimetry Mn - weight Mw number average molecular weight - weight average molecular weight pf - melting point PD - polydispersity, Mw / Mn TA - room temperature TGA - thermogravimetric analysis THF - tetrahydrofuran Tm - melting point (for a polymer) In all TGA analyzes, the heating rate was 20 ° C / minute , unless it is observed in another way.

EXPERIMENT 1 Preparation of ICH2CH2CF2CF; OCFrCF SOrF A mixture of 213 g of ICFrCF2OCF, CFrSOrF, 0.5 g of limonene and 30 g of CH: = CH; it was heated in an autoclave at 210 ° C for 8 hours. Distillation of the mixture gave 187.3 g of the title compound, boiling point 88-89 ° C / 0.041 kg / cm2 (4 kPa). NMR 19F: +45.0 (t, J = 5.7 Hz, 1F), -82.7 (m, 2F), -87.2 (, 2F), -112.7 (m, 2F), -119.3 (t, J = 17.0 Hz, 2F ).

EXPERIMENT 2 Preparation of CH2 = CHCF2CF2OCF2CF2S? 2F To a stirred solution of 136.2 g (0.3 moles) of ICH2CH2CF2CF2OCF2CF2S? 2F and 200 ml of CH3CN were added 38 g (0.376 moles) of Et3N at 75 to 80 ° C slowly for 6 hours. The reaction mixture was neutralized with concentrated H2SO4 at 0 ° C, and then poured into water and extracted with ether. The ether layer was washed with water and dried over MgSO4. After removal of the ether, a residue was distilled to give 65.3 g of pure product, boiling point 115-117 ° C, 19F NMR: +45.1 (m, 1F), -82.5 (m, 2F), -87.8 ( m, 2F), 112.5 (m, 2F), -118.0 (, 2F). NMR jH: 5.80-6.05 (m).

EXAMPLE 1 A four-necked flask fitted with a condenser and an additional funnel was charged with 7.5 g of polyethylene (Hoechst wax PE-130, number average molecular weight of 3000), 16.3 g of CH2 = CHCF2CF20CF2CF2S02F and 60 ml of 1, 2-dichlorobenzene. After the apparatus was partially evacuated and refilled with argon several times, the flask was heated to 140 ° C until all the polyethylene dissolved, and then cooled to 120 ° C. A solution of 1.23 g of di-t-butyl peroxide in 20 ml of 1,2-dichlorobenzene was added slowly over 5 hours. After the addition was complete, the reaction mixture was stirred for 8 hours. The hot solution with white solids was poured into 600 ml of acetone to precipitate the polymer. Filtration and washing with acetone gave white solids, which were dried at room temperature in vacuo to give 16.3 g of grafted polymer. IR (KBr): 1460 c "1 (s, S02F), 1205-1110 cm" 1 (s, C-F). The elemental analysis revealed that the polymer contained 3.94% sulfur, which indicated that the equivalent weight of the polymer per group -S02F was 813. The melting point of the polymer by DSC was 115 ° C and 10% loss of Weight per TGA was at 380 ° C under nitrogen.

EXAMPLE High Density Polyethylene Graft with CH2 = CHCF2CF2OCF2CF2S02F A four-necked flask fitted with a condenser and an additional funnel was charged with 7.5 g of high density polyethylene (Aldrich Chemical Co., Milwaukee, WI.USA), Mw = 125000 ), 16.3 g of CH2 = CHCF2CF2OCF2CF2S02F and 80 ml of 1,2-di chlorobenzene. After the apparatus was partially evacuated and refilled with argon several times, the flask was heated to 140 ° C until all the polyethylene dissolved, and then cooled to 125 ° C (very viscous solution). A solution of 1.23 g of di-t-butyl peroxide in 20 ml of 1,2-dichlorobenzene was added for 7 hours. After the addition was complete, the reaction mixture was heated at 130 ° C overnight. The hot solution with white solids was poured into 600 ml of acetone to precipitate the polymer, which was cut in the presence of water ice in a mixer to 16.7 g of fine powdered polymer.

EXAMPLE 3 Preparation of a Polymer Containing Sulphonic Acid A mixture of 8.0 g of the grafted polymer of Example 1, 2.5 g of KOH, 15 ml of ethanol, 5 ml of THF and 2 ml of water were stirred at room temperature overnight and at 70 ° C for 2 hours. After removal of the volatiles, the residue was treated with concentrated HCl for 30 minutes, filtered, washed with water and aqueous HCl and dried at 60 ° C in vacuum for 24 hours to give 6.7 g of solids, which could be compressed to a film at 135 ° C.

EXAMPLE 4 Preparation of a Polymer Containing Sulphonic Acid A mixture of 14.0 g of the grafted polymer in Example 2, 4.5 g of KOH, 50 ml of ethanol, 10 ml of THF and 3 ml of water was stirred at 60 ° C for 5 hours. hours, and then at room temperature overnight. After removal of the volatile compounds, the residue was treated with concentrated HCl for 40 minutes, filtered, washed with water and aqueous HCl, and dried at 70 ° C in vacuo for 8 hours to give 13.2 g of solids. The P.F. by DSC was 105 ° C and 10% weight loss by TGA was at 230 ° C in N2. The solids could be compressed to a film at 135 ° C. Elemental analysis revealed that the catalyst contained 3.19% sulfur, which indicated that the acid equivalent weight of the polymer was around 1000.

EXPERIMENT 3 Synthesis of Highly Branched Polyethylene The compound wherein BAF is tetrakis (3,5-trifluoromethylphenyl) borate (0.2952 g, 0.2 mmol) was dissolved in 200 ml of CH2C12 in a Schlenk flask in a dry ice box. The flask was connected to a Schlenk line and the flask was then evacuated briefly and refilled with ethylene from the Sc lenk line. This was stirred at RT under 1.03 kg / cm2 (101 kPa) of ethylene for 18 hours. Methanol (1200 ml) was then added to the solution, which resulted in precipitation of an oil. The oil was isolated, dissolved in 500 ml of hexanes and filtered through silica gel. Evaporation of the hexanes and drying under vacuum gave 40 g of clear oil. XH NMR analysis (CD2C12): 124 methyls per 1000 carbons of methylene. d 0.8-1.0 ppm, -CH3, 1.1-1.4 ppm, -CH2- and -CH-. The polymer exhibited a glass transition temperature of -63 ° C by DSC. GPC (THF, polyethylene standard): Mw = 108,000, Mn = 69,800, PD = 1.55.

EXAMPLE 5 Grafting of CH2 = CH (CF2) 20 (CF2) 2S02F On Highly Branched Polyethylene Highly branched polyethylene was dissolved from Experiment 3 (13.6 g) and CH2 = CH (CF2) 20 (CF2) 2S02F (29.6 g, 90.8 mmol) in 85 ml of o-dichlorobenzene at 125 ° C. A solution of o-dichlorobenzene of t-butyl peroxide (2.8 g in 30 ml of o-dichlorobenzene) was added over a period of 8 hours at 125 ° C with stirring. The solution was then allowed to stir at 125 ° C overnight.

It was then cooled to RT and poured into 400 ml of methanol with stirring. The oil was isolated, washed with 3X100 ml of methanol and dried under vacuum at 70 ° C for 6 hours. A yellow viscous oil was obtained (38.14 g). The comparison of the integral of CH2CF2- (2.00 ppm based on 1K NMR in a solvent of CD2C12) with the integrals of the methyls (0.8-1.0 ppm) and methylenes (1.1-1.4 ppm) indicated a graft comonomer content of 13.0 mol%. NMR 19F (CD2C12): 46.2 ppm, -S02F; -81.2 ppm, -86.4 ppm, -111.1 ppm, -117.4 ppm, maximum of CF2. The polymer exhibited a glass transition temperature of -53 ° C by DSC. GPC (THF, polystyrene standard): Mw = 87,200, Mn = 51,000, PD = 1.71.

EXAMPLE 6 Preparation of a Polymer Containing Potassium Sulfonate The grafted polymer of Example 5 (23.64 g) was mixed with 10 g of KOH, 70 ml of THF, 60 ml of ethanol and 5 ml of water. Agitation of the mixture at RT resulted in hydrolysis of the S02F group. After stirring at RT for 2 hours, this mixture was brought to reflux for 6 hours. The solvent was then evaporated under vacuum at 60 ° C for 8 hours. The solid was dissolved in 400 ml of acetone. The mixture was filtered through Celite®. 400 ml of THF were added to the filtrate. This mixture was filtered through Celite®. Evaporation of the solvents and drying under vacuum gave 17.7 g of a yellowish orange brittle solid. This solid dissolves in water at RT. Its solution in water is neutral base.

EXAMPLE 7 Preparation of a Polymer Containing Sulphonic Acid The product of Example 6 (15.0 g) was mixed with 80 ml of concentrated HCl. This was vigorously stirred for 12 hours. The resulting solid was filtered, washed with 2X5 ml of concentrated HCl and dried under vacuum at 70 ° C for 6 hours. A red solid (8.5 g) was obtained.

EXAMPLE 8 Grafting of CH2 = CH (CF2) 20 (CF2) 2SQ2F On Poly (tetramethylene ether) glycol A solution of o-dichlorobenzene of t-butyl peroxide (0.60 g of peroxide in 7 ml of o-dichlorobenzene) was slowly added to a solution of 3.56 g of PTMEG (Mw = 11,700, Mn = 8,290, polyethylene standard, THF) and 6.39 g of the title sulfonyl fluoride in 20 ml of p-dichlorobenzene at 125 ° C. The addition was completed in 2.5 hours. The solution was allowed to stir at 125 ° C for another 6 hours. The volatiles were evaporated at 125 ° C under total vacuum for 5 hours, leaving 9.68 g of a viscous white oil as the product. 19 F NMR (CD2C12): 44.5 ppm, -S02F; -82.8 ppm, -88.2 ppm, -112.8 ppm, -119.4 ppm, maximum of CF2. The polymer exhibited a glass transition temperature of -68 ° C by DSC. GPC (THF, polystyrene standard): Mw = 27,800, Mn = 11, 300, PD = 2.46.

EXAMPLE 9 Preparation of a Polymer Containing Potassium Sulfonate To a mixture of 9.67 g of the product of Example 8, and 2.5 g of KOH were added 20 ml of THF, 15 ml of ethanol and 1.5 ml of water. Stirring at RT resulted in an exothermic reaction. This was allowed to stir at RT for 1 hour, and then brought to reflux for 5 hours. The solvents were evaporated under vacuum. The solid was extracted with 100 ml of acetone. This mixture was filtered through Celite®, followed by washing with 3X10 ml of acetone. 130 ml of THF were added to the filtrate. This was filtered through Celite®. Evaporation of the solvents and drying under vacuum at 105 ° C overnight gave 8.8 g of a brittle yellow solid. This product dissolves in water at RT to form a solution that is neutral.

EXAMPLE 10 Preparation of a Polymer Containing Sulphonic Acid To 4.23 g of the polymer of Example 9 in a flask was added 20 ml of concentrated HCl. This mixture was allowed to stir vigorously for 20 minutes at TA. The top layer was decanted. This procedure was repeated two more times using 15 ml of concentrated HCl. The viscous oil was dried at 105 ° C under complete vacuum for 6.5 hours. A dark red viscous oil (2.41 g) was obtained.

EXAMPLE 11 The potassium salt of a polyethylene grafted with CH2 = CH (CF2) 20 (CF2) 2S02F hydrolyzate (13 mol% grafted co-monomer, Mw = 97,600, Mn = 67,100) is soluble in water. The potassium salt of the hydrolyzed ethylene copolymer of CH2 = CH (CH2) 4 (CF2) 40 (CF2) 2S02F made with a Pd catalyst (8.5 mole% comonomer, Mw = 120,000, Mn = 78,900) is not very soluble in water The polymer made with the Pd catalyst was made using the compound as the catalyst, and (0.0205 g, 0.024 mmol) and CH2CH (CH2) 4 (CF2) 40 (CF2) 2F (3.5 g, 7.26 mmol) were dissolved in 18 ml of CH2C12 in a Schlenk flask in an ice box dry. The flask was connected to a Schlenk line and the flask was then evacuated briefly and refilled with ethylene from the Schlenk line. This was stirred at RT under 1.03 kg / cm3 (101 kPa) of ethylene for 72 hours. The solvent was evaporated after filtration. The viscous oil was dissolved in 10 ml of CH2C12, followed by the addition of 100 ml of methanol. The top layer was decanted. The reverse precipitation was repeated two more times, followed by vacuum drying to provide 3.68 g of a light yellow viscous oil. GPC (THF, polystyrene standard): Mw = 120,000, Mn = 78,900, P / D = 1.54. The change numbers for ethylene and comonomer are 2098 and 195, respectively. The polymer was hydrolyzed to produce a polymer containing sulfonic acid.

EXPERIMENT 4 Polymerization of a Cyclic Ether In a dry ice box, the product of Example 4 (0.50 g), THF (3.0 g), THF / 3-Me-THF (55/45 mole%, 7.00 g) and acetic anhydride (0.50 g) were placed in a 20 ml vial equipped with a stir bar. After stirring for one hour at room temperature, the vial was removed from the dry ice box and the polymerization was terminated by the addition of THF, water (1.00 ml) and ether. The solids were removed via filtration and the resulting filtrate was concentrated under reduced pressure and then dried under vacuum to provide 2.91 g of polymer. Analysis by GPC (polystyrene standard (PS STD)): Mn = 11300, Mw = 16800, PD = 1.48. It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.

Claims (11)

CLAIMS Having described the invention as above, the content of the following claims is claimed as property:

1. A process for producing a partially fluorinated polymer, characterized in that it comprises contacting in liquid phase a first polymer containing hydrogen bound to carbon with a compound of the formula H2C = CHCR1R2R6Y, and a source of free radicals, wherein: R1 and R2 each independently fluorine or perfluoroalkyl containing from 1 to 20 carbon atoms; Rb is fluorinated alkylene containing 1 to 20 carbon atoms and which optionally contains one or more ether or alkylene groups containing from 1 to 20 carbon atoms and which optionally contains one or more ether groups; and Y is -S02F, -C02R3, P (0) (OR3) 2, S03H, -S03M or -S (O) 2NHS (O) 2R4; wherein: R3 is independently hydrocarbyl or substituted hydrocarbyl containing from 1 to 20 carbon atoms; R 4 is perfluoroalkyl containing from 1 to 20 carbon atoms; M is an alkali metal; and with the proviso that the contact is carried out at a temperature at which the source of free radicals generates free radicals.

2. A partially fluorinated polymer, characterized in that it comprises, branches having the formula -CH2-CH2-CR1R2R6Y, wherein: R1 and R2 are each independently fluorine or perfluoroalkyl containing from 1 to 20 carbon atoms; Rb is fluorinated alkylene containing from 1 to 20 carbon atoms and optionally containing one or more ether or alkylene groups containing from 1 to 20 carbon atoms and which optionally contains one or more ether groups; and Y is -S02F, -C02R3, P (0) (OR3) 2, S03H, -S (O) 2NHS (O) 2R4 or -S03M or; R3 is independently hydrocarbyl or substituted hydrocarbyl containing from 1 to 20 carbon atoms; R 4 is perfluoroalkyl containing from 1 to 20 carbon atoms; M is an alkali metal; and with the proviso that a polymer backbone contains hydrogen bound to carbon.

3. The process according to claim 1, characterized in that Rb is perfluoroalkylene or perfluoroalkylene substituted with ether.

The polymer according to claim characterized in that R < it is perfluoroalkylene or perfluoroalkylene substituted with ether.

5. The process according to claim 1, characterized in that R is - (CF2) d- wherein d is 2 to 20 or -CF2OCF2CF2-.

6. The polymer according to claim 2, characterized in that Rb is - (CF2) d- wherein d is 2 to 20 or -CF2OCF2CF2-.

7. The process according to claim 1, characterized in that Y is -S02F.

8. The polymer according to claim 2, characterized in that Y is -SO? F.

9. The polymer according to claim 2, characterized in that R ° is - (CF2) d- wherein d is 2 to 20 or -CF2OCF2CF2-, and Y is S02F, S03M or S03H, wherein M is an alkali metal.

10. The process according to claim 3, characterized in that Y is -S02F.

11. The polymer according to claim 4, characterized in that Y is -S0 F.