FLUORINE-CONTAINING ALTERNATING COPOLYMER MACROMONOMER AND SYNTHESIS METHOD THEREOF

Abstract

The present invention relates to a fluorine-containing alternating copolymer macromonomer and a synthesis method thereof. The synthesis method comprises steps of: subjecting a fluorine-containing alternating copolymer to a reduction reaction at 60-100° C. in an organic solvent in the presence of a reducing agent and a first catalyst to obtain a reduction product; in the presence of a second catalyst, reacting the reduction product with a mercapto-monohydric alcohol in an organic solvent at 60-100° C., to obtain a hydroxyl-terminated fluorine-containing alternating copolymer; and in the presence of a third catalyst, reacting the hydroxyl-terminated fluorine-containing alternating copolymer with an acrylic monomer or acryloyl chloride monomer at 0-30° C., to obtain the fluorine-containing alternating copolymer macromonomer. In the present invention, a fluorine-containing alternating copolymer macromonomer is initially synthesized from a fluorine-containing alternating copolymer through polymer modification.

Claims

1. A method for synthesizing a fluorine-containing alternating copolymer macromonomer, comprising steps of: (1) subjecting a fluorine-containing alternating copolymer of Formula (1) to a reduction reaction at 60-100° C. in an organic solvent in the presence of a reducing agent and a first catalyst, to obtain a reduction product of Formula (2) after the reaction is completed: ##STR00007## where a=4-8, b=2-6, and n=1-30; (2) in the presence of a second catalyst, reacting the reduction product with a mercapto-monohydric alcohol of Formula (3) in an organic solvent at 60-100° C., to obtain a hydroxyl-terminated fluorine-containing alternating copolymer of Formula (4) after the reaction is completed: ##STR00008## where c=1-10, a=4-8, b=2-6, and n=1-30; and (3) in the presence of a third catalyst, reacting the hydroxyl-terminated fluorine-containing alternating copolymer with an acrylic monomer or acryloyl chloride monomer at 0-30° C., to obtain the fluorine-containing alternating copolymer macromonomer after the reaction is completed.

2. The synthesis method according to claim 1, wherein in Step (1), the molar ratio of the fluorine-containing alternating copolymer and the reducing agent is 1:2-100, and the reducing agent is tributyltin hydride.

3. The synthesis method according to claim 1, wherein in Step (1), the molar ratio of the fluorine-containing alternating copolymer and the first catalyst is 1: 2-300, and the first catalyst is azobisisobutyronitrile, or dibenzoyl peroxide.

4. The synthesis method according to claim 1, wherein in Step (2), the second catalyst is 1,1′-azo (cyanocyclohexane), or azobisisobutyronitrile; and the molar ratio of the reduction product and the second catalyst is 1:3-6.

5. The synthesis method according to claim 1, wherein in Step (2), the molar ratio of the reduction product to the mercapto-monohydric alcohol is 1:10-100.

6. The synthesis method according to claim 1, wherein in Step (3), the third catalyst is triethylamine or pyridine; and the molar ratio of the hydroxyl-terminated fluorine-containing alternating copolymer to the third catalyst is 1:1.5-2.

7. The synthesis method according to claim 1, wherein in Step (3), the acrylic monomer is methacrylic acid or acrylic acid.

8. The synthesis method according to claim 1, wherein in Step (3), the acryloyl chloride monomer is methacryloyl chloride, or acryloyl chloride.

9. The synthesis method according to claim 1, wherein in Step (3), the molar ratio of the hydroxyl-terminated fluorine-containing alternating copolymer to the acrylic monomer or acryloyl chloride monomer is 1:1.1-2.

10. A fluorine-containing alternating copolymer macromonomer prepared by the method according to claim 1, having a chemical Formula (5): ##STR00009## where R═H or CH.sub.3, c=1-10, a=4-8, b=2-6, and n=1-30; and the fluorine-containing alternating copolymer macromonomer has a molecular weight of 540-16500 g/mol.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG. 1 shows the test results by .sup.1H NMR of a fluorine-containing alternating copolymer (AB).sub.n prepared in Example 1 of the present invention;

[0033] FIG. 2 shows the test results by .sup.19F NMR of the fluorine-containing alternating copolymer (AB).sub.n prepared in Example 1 of the present invention;

[0034] FIG. 3 shows the test results by .sup.1H NMR of the fluorine-containing alternating copolymer (AB).sub.n before and after reduction in Example 2 of the present invention;

[0035] FIG. 4 shows the test results by GPC of the fluorine-containing alternating copolymer (AB).sub.n before and after reduction in Example 2 of the present invention;

[0036] FIG. 5 shows the test results by .sup.1H NMR of a reduced fluorine-containing alternating copolymer before and after reaction with mercaptoethanol in Example 3 of the present invention;

[0037] FIG. 6 shows the test results by .sup.1H NMR of a macromonomer produced by reacting a hydroxyl-terminated fluorine-containing alternating copolymer with methacryloyl chloride in Example 3 of the present invention; and

[0038] FIG. 7 shows the test results by .sup.1H NMR of the product obtained by directly reacting of a non-reduced fluorine-containing alternating copolymer (AB).sub.n with mercaptoethanol in the comparative example.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] The specific embodiments of the present invention will be described in further detail with reference to the accompanying drawings and examples. The following examples are intended to illustrate the present invention, instead of limiting the scope of the present invention.

[0040] In the following examples of the present invention, 1,7-octadiene and methacryloyl chloride need to run through a neutral alumina column before use, while all other chemical reagents can be obtained commercially and used directly.

[0041] The characterization conditions of the product are as follows:

[0042] .sup.1H NMR and .sup.19F NMR: INOVA 600 MHz Nuclear Magnetic Resonance Spectrometer, solvent CDCl.sub.3, and internal standard TMS;

[0043] Preparation of test samples for .sup.1H NMR and .sup.19F NMR: About 15 mg of the sample was weighed, fed to an NMR tube, and added with 0.6 mL of CDCl.sub.3.

[0044] Molecular weight (M.sub.n) and polydispersity index (PDI): Waters 1515 Gel Permeation chromatograph (GPC), mobile phase tetrahydrofuran (THF), and column temperature: 30° C.

[0045] Preparation of test samples for GPC: About 10 mg of the sample was weighed, dissolved in 3-4 mL of THF, filtered through a syringe filter after thorough dissolution, and added to a sample vial.

Example 1 Synthesis of Fluorine-Containing Alternating Copolymer (AB).SUB.n

[0046] Dodecafluoro-1,6-diiodohexane (C.sub.6F.sub.12I.sub.2), sodium ascorbate (AsAc—Na), tris(bipyridine)ruthenium dichloride (Ru(bpy).sub.3Cl.sub.2), methanol (1 mL), 1,4-dioxane (3 mL), and 1,7-octadiene (C.sub.8H.sub.14) were sequentially added to a 5 mL ampoule in proportion, where the ratio of [C.sub.6F.sub.12I.sub.2].sub.0:[C.sub.8H.sub.14].sub.0:[Ru(bpy).sub.3Cl.sub.2].sub.0:[AsAc—Na].sub.0=1:1:0.02:0.5 (molar ratio), based on 0.5 mmol of dodecafluoro-1,6-diiodohexane. After adding a stir bar, three rounds of freezing-evacuating-introducing argon were performed, and the ampoule was flame-sealed. The ampoule was positioned under blue LED irradiation and stirred at room temperature. At this time, the solution appeared bright red. After a predetermined time of reaction, the ampoule was removed. The solution appeared dark brown. The solution was diluted with 1-2 mL of tetrahydrofuran, precipitated in a large amount of methanol in a disposable plastic cup, sealed with a plastic wrap and allowed to stand overnight in a refrigerator. Suction filtration under reduced pressure afforded a purple-black product, which was then dissolved with a small amount of tetrahydrofuran, passed through a neutral alumina column to remove metal salts, and precipitated in a large amount of methanol. The precipitate was white at this time. After standing overnight in a refrigerator, suction filtration under reduced pressure afforded a white product. The resulting white product was dried to a constant weight in a thermostatic oven at 40° C. under vacuum, and then weighed. Finally, a fluorine-containing alternating copolymer (AB).sub.n was obtained (yield 95%). The fluorine-containing alternating copolymer (AB).sub.n has the following chemical structure:

##STR00004##

[0047] where a=6, b=4, and n=6-7.

[0048] The molecular weight (M.sub.n) and polydispersity index (PDI) of the polymer were measured by gel permeation chromatography (GPC), and the structure was characterized by .sup.1H NMR and .sup.19F NMR. The results are shown in FIGS. 1-2. In FIG. 1, the peaks at different chemical shifts on the NMR spectrum can be attributed to corresponding moieties in the structural formula of the polymer. The peak at 7.26 ppm is the shift peak of deuterated chloroform (CDCl.sub.3), and the peak at 3.76 ppm is the shift peak of —CH.sub.2 of tetrahydrofuran (THF). In FIG. 2, the peaks at different chemical shifts on the NMR spectrum can be attributed to corresponding moieties in the structural formula. The above results indicate that the expected fluorine-containing alternating copolymer (AB).sub.n is obtained through the above-mentioned steps.

Example 2 Reduction of (AB).SUB.n

[0049] Tributyl tin hydride was used as a reducing agent and azobisisobutyronitrile (AIBN) was used as a catalyst. The resulting fluorine-containing alternating copolymer (AB).sub.n was reduced. The reaction route and specific steps were as follows.

##STR00005##

[0050] The fluorine-containing alternating copolymer (AB).sub.n (1 eq.) prepared in Example 1, azobisisobutyronitrile (30 eq.), toluene (6.0 mL), and tributyl tin hydride (10 eq.) were weighed in proportion sequentially and added to a 10 mL ampoule. After adding a stir bar, three rounds of freezing-evacuating-introducing argon were performed, and the ampoule was flame-sealed. The ampoule was placed in an oil bath at 90° C., stirred, reacted for a predetermined period of time and then removed. The ampoule was opened, and the solution was diluted with 1-2 mL of tetrahydrofuran, precipitated in a large amount of methanol, sealed with a plastic wrap and allowed to stand overnight in a refrigerator. Suction filtration under reduced pressure afforded a white product. The resulting white product was dried to a constant weight in a thermostatic oven at 40° C. under vacuum, and then weighed. Finally, a reduced fluorine-containing alternating copolymer was obtained.

[0051] FIG. 3 shows the .sup.1H NMR spectrum of (AB).sub.n before and after reduction. After reduction of the C—I bond, the shift peak around the shift peak attributed to —CH.sub.2CH(I)CH.sub.2— (4.3 ppm) is attributed to hydrogen which is on the same carbon with iodo before reduction, and the shift peak at about 2.9 ppm is attributed to the fact that hydrogen on a carbon adjacent to the carbon to which iodo is attached before reduction disappears, and a new shift peak of —CH.sub.2CH.sub.2CH.sub.2— is incorporated into the shift peaks at 1-2 ppm.

[0052] FIG. 4 shows a GPC chromatogram of (AB).sub.n before and after reduction. It can be seen that before reduction, the molecular weight of (AB).sub.n is 6000 g/mol, and M.sub.w/M.sub.n=1.69; and after reduction, the molecular weight of the product is 3000 g/mol, and M.sub.w/M.sub.n=1.07. After reduction, the molecular weight is negatively increased, which corresponds to the report regarding commercial fluorine-containing polyolefins (where the inverted peak is caused by that refractive index of the sample is less than that of the mobile phase). The decrease in molecular weight after reduction prevents steric hindrance due to excessive molecular weight from affecting the subsequent reaction, and thus is more conducive to the subsequent reaction. The polydispersity index decreases after reduction. The above results indicate that the C—I bond on the fluorine-containing alternating copolymer has been reduced, and macromonomer synthesis can be carried out in the next step.

Example 3 Synthesis of Fluorine-Containing Alternating Copolymer Macromonomer

[0053] (1) Addition with Mercaptoethanol:

[0054] 1,1′-azobis(cyanocyclohexane) (ABCN) was used as a catalyst to initiate the addition of the reduced fluorine-containing alternating copolymer (AB).sub.n with β-mercaptoethanol. A fluorine-containing alternating polyolefin having a terminal hydroxyl group (—OH) was obtained, and then the terminal hydroxyl group was reacted with methacryloyl chloride to finally produce a fluorine-containing alternating copolymer macromonomer. The reaction route and steps were as follows.

##STR00006##

[0055] The reduced fluorine-containing alternating copolymer (1 eq.) prepared in Example 2, ABCN (3 eq.), toluene (4.0 mL), and β-mercaptoethanol (20 eq.) were weighed in proportion sequentially and added to a 5 mL ampoule. After adding a stir bar, three rounds of freezing-evacuating-introducing argon were performed, and the ampoule was flame-sealed. The ampoule was placed in an oil bath at 90° C., stirred, reacted for a predetermined period of time and then removed. The ampoule was opened, and the solution was diluted with 1-2 mL of tetrahydrofuran, precipitated in a large amount of methanol in a disposable plastic cup, sealed with a plastic wrap and allowed to stand overnight in a refrigerator. Suction filtration under reduced pressure afforded a white product. The resulting white product was dried to a constant weight in a thermostatic oven at 40° C. under vacuum, and then weighed. Finally, a hydroxyl-terminated fluorine-containing alternating copolymer was obtained.

[0056] FIG. 5 shows the test results by .sup.1H NMR of a reduced fluorine-containing alternating copolymer before and after reaction with mercaptoethanol. The peaks indicated by letters on the .sup.1H NMR spectrum are attributed to the hydrogen atoms indicated by the same letters in the corresponding structural formula. It can be seen from the figure that the reaction is completed successfully. Two new shift peaks of mercaptoethanol are generated on the .sup.1H NMR spectrum, and the double bond peak disappears completely. When not reduced, due to the higher C—I bond activity and lower bond energy, it can react with thiol to form HI, which inhibits the addition reaction of double bond with thiol. After reduction of the C—I bond, the free radical addition reaction occurs as expected, and it can be confirmed from the .sup.1H NMR spectrum of FIG. 5 that a hydroxyl-terminated fluorine-containing alternating copolymer is synthesized.

[0057] (2) Reaction with Methacryloyl Chloride

[0058] The hydroxyl-terminated fluorine-containing alternating copolymer (1 eq.) obtained in Step (1), chloroform (3 mL), triethylamine (1.5 eq.), and methacryloyl chloride (1.5 eq.) were weighed in proportion sequentially and added to a 5 mL ampoule. After adding a stir bar, three rounds of freezing-evacuating-introducing argon were performed, and the ampoule was flame-sealed. The ampoule was placed in a water bath at 25° C., stirred, reacted for a predetermined period of time and then removed. The solution was diluted with 1-2 mL of tetrahydrofuran, precipitated in a large amount of methanol in a disposable plastic cup, sealed with a plastic wrap and allowed to stand overnight in a refrigerator. Suction filtration under reduced pressure afforded a white product. The resulting white product was dried to a constant weight in a thermostatic oven at 40° C. under vacuum, and then weighed. Finally, a fluorine-containing alternating copolymer macromonomer was obtained.

[0059] The .sup.1H NMR spectrum of the macromonomer produced by the reaction of the hydroxyl-terminated fluorine-containing alternating copolymer with methacryloyl chloride is shown in FIG. 6. The peaks at different chemical shifts on the .sup.1H NMR spectrum can be attributed to corresponding moieties in the structural formula. The shift peak at about 3 ppm is the shift peak of the catalyst triethylamine (Et.sub.3N), and the peak at 7.26 ppm is the shift peak of the solvent deuterated chloroform (CDCl.sub.3). The results show that the fluorinated alternating copolymer macromonomer is successfully obtained through the above method.

COMPARATIVE EXAMPLES

[0060] After the fluorine-containing alternating copolymer (AB).sub.n in Example 1 was obtained, it was directly subjected to an addition reaction with mercaptoethanol (as shown in Table 1: the molar ratio of the fed materials, the reaction time, the catalyst type, the solvent type and volume, and others were varied). Theoretically, the terminal double bond of the fluorine-containing alternating copolymer reacts with thiol. However, the analysis of .sup.1H NMR spectra (FIG. 7) shows that the peak shape and number of the double bond are basically unchanged (where only the solvent peak is changed, where after modification with mercaptoethanol, the shift peak of —CH.sub.2 in tetrahydrofuran (THF) at 3.76 ppm disappears, and the shift peak of —CH.sub.3 in methanol appears at 3.49 ppm). It can also be seen from the results by GPC that the molecular weight of the polymer basically remains the same.

TABLE-US-00001 TABLE 1 Reaction of fluorine-containing alternating copolymer (AB).sub.n with mercaptoethanol under different conditions [(AB).sub.n].sub.0: Comparative [Bu.sub.3HSn].sub.0: Time V.sub.Solvent .sup.aM.sub.n .sup.bM.sub.n Examples [initiator].sub.0 (h) Solvent (mL) (g/mol) .sup.aPDI (g/mol) .sup.bPDI 1 1:10:0.5 10 Toluene 4 6600 1.47 7700 1.62 2 1:10:0.5 24 Toluene 4 6700 1.57 6500 1.55 3 1:10:0.5 48 Toluene 4 5000 1.39 4600 1.50 4 1:20 AM:1 24 Toluene 4 5900 1.56 5900 1.55 5 1:100:5 48 Toluene 4 5900 1.56 6200 1.52 6 1:20 AM:3 24 Toluene 4 5900 1.56 6000 1.33 7 1:20 AM:3 24 Toluene 2 8800 1.50 9200 1.43 8 1:40 AM:6 24 Toluene 2 8800 1.50 9300 1.40 9 1:20 AM:3 48 Toluene 2 8800 1.50 9300 1.48 10 1:20 AM:3 24 DMSO 2 8800 1.50 12300 1.37 11 1:20 AM:3 24 DMF 2 8800 1.50 11300 1.42

[0061] In Comparative Examples 1-5, the initiator is AIBN, and in Comparative Examples 6-11, the initiator is ABCN. .sup.aM.sub.n is the molecular weight of (AB).sub.n before reaction with mercaptoethanol, and .sup.aPDI is the polydispersity index of (AB).sub.n before reaction with mercaptoethanol. .sup.bM.sub.n is the molecular weight of (AB).sub.n after reaction with mercaptoethanol, and .sup.bPDI is the polydispersity index of (AB).sub.n after reaction with mercaptoethanol.

[0062] While preferred embodiments of the present invention have been described above, the present invention is not limited thereto. It should be appreciated that some improvements and variations can be made by those skilled in the art without departing from the technical principles of the present invention, which are also contemplated to be within the scope of the present invention.