An amphiphilic fluorine-containing block polymer, a preparation method thereof, and application thereof in an aqueous fluorine-containing emulsion

Abstract

The application belongs to the field of material preparation, and particularly relates to an amphiphilic fluorine-containing block polymer, a preparation method thereof and application thereof in a water-based fluorine-containing emulsion. The amphiphilic fluorine-containing block polymer prepared by the application uses short-chain fluorine-containing acrylate as monomer, breaking through the dependence on traditional PFAS surfactants. The block polymer synthesized by the RAFT method plays a stabilizing role as a polymer surfactant, and the negative charged end group further enhances the emulsion stability through electrostatic repulsion. The water-based fluorine-containing emulsion prepared by the application has uniform particle size distribution, and the water phase as a continuous phase widens the application of the water-based fluorine-containing emulsion in coatings, solving the defect of poor stability of the water-based fluorine-containing emulsion in the industry.

Description

Technical Field

[0001] This invention belongs to the field of materials preparation, specifically relating to an amphiphilic fluorinated block polymer and its preparation method, as well as its application in aqueous fluorinated emulsions. Background Technology

[0002] Fluorinated materials are promising candidates in many fields due to their inherent hydrophobicity, chemical stability, and environmental compatibility. The preparation of aqueous fluorinated emulsions has attracted considerable attention in recent years; however, their practical application is hindered by key challenges: traditional emulsifiers (small molecule surfactants, uncontrolled polymers) lead to poor emulsion stability and performance degradation due to residues. Although traditional fluorinated surfactants (such as PFAS) can stabilize certain fluorinated emulsions, their potential environmental persistence, bioaccumulation, and insufficient stability in complex systems severely limit their industrial-scale scaling. Reversible addition-fragmentation chain transfer (RAFT) polymerization, as a typical controlled / living radical polymerization technique, can synthesize block polymers with well-defined molecular structures. Unlike traditional small-molecule surfactants, these block polymers synthesized via RAFT act as polymer surfactants, providing stability: their fluorinated hydrophobic segments are highly compatible with fluorinated oils, forming strong physical entanglements with the oil phase; simultaneously, their hydrophilic segments extend into the aqueous phase, constructing a steric hindrance layer, while the negatively charged end groups further enhance colloidal stability through electrostatic repulsion. Currently, in the preparation of amphiphilic fluorinated block polymers, fluctuations in conditions can easily lead to initiator deactivation and chain growth termination, resulting in a broadened polymer molecular weight distribution and making it difficult to obtain block copolymers with uniform structures; furthermore, problems such as excessive hydrophilic end growth, incomplete polymerization of fluorinated segments, and bioaccumulation can easily occur. Summary of the Invention

[0003] To address the problems existing in the prior art, this invention provides an amphiphilic fluorinated block polymer. The polymer prepared by this invention can control the solubility and dispersibility of the target product by adjusting the degree of polymerization of each block, and enhances the interfacial bonding force between the fluorinated and hydrophilic segments, thereby improving the toughness and chemical resistance of the material.

[0004] The present invention also provides a method for preparing the above-mentioned amphiphilic fluorinated block polymer.

[0005] Another object of the present invention is to provide the application of the above-mentioned amphiphilic fluorinated block polymer in the preparation of aqueous fluorinated emulsions.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides an amphiphilic fluorinated block polymer, the structural formula of which is: .

[0007] This invention also provides a method for preparing the above-mentioned amphiphilic fluorinated block polymer, comprising the following steps: (1) Mix acrylic acid, chain transfer agent, initiator and organic solvent, and reflux the mixture at a certain temperature; (2) After the above reaction is completed, add the fluorinated acrylate and initiator to the reaction system, and continue the reaction by reflux at a certain temperature; (3) After the reaction is complete, the product is cooled to room temperature, n-hexane is added dropwise, the product is obtained by precipitation, and dried to obtain an amphiphilic fluorinated block polymer.

[0008] Preferably, in step (1), the molar ratio of acrylic acid to chain transfer agent is 100:1.32-3.33; the molar ratio of acrylic acid to initiator is 100:1.0-2.5, preferably 100:1.5; the organic solvent accounts for 75% of the total phase by mass; the chain transfer agent is S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide, S,S′-di(1-dodecyl)trithiocarbonate, and S-dodecyl-S″-propionic acid. At least one of isopropionic acid-trithiocarbonate; preferably, the chain transfer agent is S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid)trithioester; the initiator is at least one of sodium persulfate, ammonium persulfate, potassium persulfate, azobisisobutyronitrile, and azobisisobutyramidine hydrochloride; preferably, the initiator is azobisisobutyronitrile; the organic solvent is at least one of 1,4-dioxane, ethanol, and dimethyl carbonate; preferably, the organic solvent is 1,4-dioxane.

[0009] Preferably, in step (1), the reflux reaction is carried out at 60-80°C for 3-24 hours. Preferably, in step (2), the molar ratio of the fluorinated acrylate to the initiator is 100:1.5; the fluorinated acrylate is at least one of trifluoroethyl methacrylate, hexafluorobutyl methacrylate, and octafluoropentyl methacrylate, preferably trifluoroethyl methacrylate; the initiator is at least one of sodium persulfate, ammonium persulfate, potassium persulfate, azobisisobutyronitrile, and azobisisobutyronitrile hydrochloride; preferably, the initiator is azobisisobutyronitrile.

[0010] Preferably, in step (2), the reflux reaction is carried out at a temperature of 60-80°C for 3-24 hours.

[0011] Another object of the present invention is to provide the application of the amphiphilic fluorinated block polymer prepared by the above method in the preparation of aqueous fluorinated emulsions.

[0012] This invention also provides a method for preparing aqueous fluorinated emulsions from the amphiphilic fluorinated block polymer obtained by the above method, comprising the following steps: (a) The amphiphilic block polymer and sodium undecenoate were dissolved in deionized water, and then the oil phase was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. (b) The pre-emulsified aqueous emulsion is added to an initiator and refluxed under a nitrogen atmosphere and at a certain temperature to obtain an aqueous fluorinated emulsion.

[0013] Preferably, in step (a), the mass ratio of the amphiphilic block polymer to sodium undecenoate is 1:0.8-1.4, preferably 1:1; the oil phase is a fluorinated acrylate or a mixture of fluorinated acrylate and a vinyl silane coupling agent, or a mixture of fluorinated acrylate, vinyl acetate, and 4-hydroxybutyl vinyl ether; the fluorinated acrylate is at least one of trifluoroethyl methacrylate, hexafluorobutyl methacrylate, and octafluoropentyl methacrylate; preferably hexafluorobutyl methacrylate; the vinyl silane coupling agent is vinyltrimethoxysilane, vinyltriethyl... The mixture contains at least one of oxysilane and γ-methacryloyloxypropyltrimethoxysilane, preferably vinylsilane coupling agent; the mass ratio of the vinylsilane coupling agent to the fluorinated acrylate is 1:1-7; the oil phase accounts for 10-40% of the oil-water total phase; the mass ratio of hexafluorobutyl methacrylate, vinyl acetate and 4-hydroxybutyl vinyl ether is 1:0.3-0.7:1-1.5; the mass ratio of the fluorinated acrylate, vinyl acetate and 4-hydroxybutyl vinyl ether is 1:0.3-0.7:0.5-1.5.

[0014] Preferably, in step (b), the initiator is at least one of sodium persulfate, ammonium persulfate, potassium persulfate, azobisisobutyronitrile, and azobisisobutyramidine hydrochloride, preferably potassium persulfate; the amount of the initiator added accounts for 0.5-1.5 wt% of the total oil phase; the reflux reaction is carried out at 60-80°C for 3-6 hours.

[0015] Furthermore, the method described in this invention can also be applied to the preparation of aqueous fluorinated emulsions containing only a single fluorinated monomer, or composite emulsions copolymerized with other functional monomers (such as vinyl acetate, 4-hydroxybutyl vinyl ether, etc.), thus broadening the application scenarios. The short-chain fluorinated polymer prepared by this invention exhibits low bioaccumulation and excellent stability in complex systems. The aqueous fluorinated emulsion prepared based on this polymer exhibits good UV resistance, acid and alkali resistance, and good hydrophobicity of the fluorinated component on the surface after film formation.

[0016] The beneficial effects of this invention are as follows: (1) The amphiphilic fluorinated block polymer prepared by the present invention uses short-chain fluorinated acrylate monomers, which breaks through the dependence on traditional PFAS surfactants; and the block polymer synthesized by the RAFT method plays a stabilizing role as a polymer surfactant, while the negatively charged end groups further enhance the stability of the emulsion through electrostatic repulsion.

[0017] (2) The waterborne fluorinated emulsion prepared by the present invention has a uniform particle size distribution. Its aqueous phase, as a continuous phase, broadens its application in coatings and solves the problem of poor stability of waterborne fluorinated emulsions in the current industry.

[0018] (3) The aqueous fluorinated emulsion prepared by the present invention has excellent film-forming properties, as well as excellent chemical resistance and waterproof performance. Attached Figure Description

[0019] Figure 1 Gel chromatograms of amphiphilic fluorinated block polymers prepared under different conditions; Figure 2 Infrared spectra of amphiphilic fluorinated block polymers prepared under different conditions; Figure 3 NMR spectra of amphiphilic fluorinated block polymers prepared under different conditions; Figure 4 The molecular weight and molecular weight distribution of amphiphilic fluorinated block polymers prepared under different conditions; Figure 5 Particle size distribution of aqueous fluorinated emulsions with different ratios of vinyl silane coupling agent to fluorinated acrylate; Figure 6 This is a scanning electron microscope image of the aqueous fluorinated emulsion in Example 1; Figure 7 The diagram shows the zeta potential of the aqueous fluorinated emulsion at different dilution concentrations in Example 1. Figure 8 Photographs showing the emulsion stability in Examples 8, 9, and 1; Figure 9 The film-forming properties of the emulsions in Examples 8, 9, and 1 on a glass plate; Figure 10 Photographs showing the waterproof properties of Example 9; Figure 11 Photographs showing the chemical resistance of Example 9; Figure 12 Image showing the transparency of the coating prepared in Example 9. Detailed Implementation

[0020] The method of the present invention will be described below through specific embodiments, but the scope of protection of the present invention is not limited thereto.

[0021] In some embodiments, the amphiphilic fluorinated block polymer prepared according to the present invention has a reaction time of 3h-24h, preferably 12h.

[0022] In some embodiments, the aqueous fluorinated emulsion prepared according to the present invention is reacted at a temperature of 60°C-80°C, and preferably at a reaction time of 70°C.

[0023] In some embodiments, the aqueous fluorinated emulsion prepared according to the present invention has an amphiphilic block polymer and sodium undecenoate in a mass ratio of 1:0.8-1.4, preferably 1:1.

[0024] In some embodiments, the aqueous fluorinated emulsion prepared by the present invention is prepared by polymerizing a vinyl silane coupling agent and a fluorinated acrylate at a mass ratio of 1:1, 1:1.67, 1:3, or 1:7, preferably 1:3.

[0025] In some embodiments, the aqueous fluorinated emulsion prepared by the present invention has a mass ratio of fluorinated acrylate and vinyl silane coupling agent to the oil-water total phase of 1:9, 1:4, 1:2.33, or 1:1.5, preferably 1:2.33.

[0026] In some embodiments, the waterborne fluorinated emulsion prepared according to the present invention preferably has a mass ratio of fluorinated acrylate: vinyl acetate: 4-hydroxybutyl vinyl ether of 2:1:2.

[0027] Example 1 Acrylic acid (3.00 g), azobisisobutyronitrile (0.045 g), and S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide (0.3 g) were dissolved in 20 ml of 1,4-dioxane, and then transferred to a 100 ml three-necked flask. The mixture was then purged with nitrogen, condensed, and reacted in a water bath at 70 °C for 6 h. After the reaction was complete, azobisisobutyronitrile (0.105 g) was dissolved in trifluoroethyl methacrylate (7 g) and added to the flask. The reaction was continued under the same conditions for 12 h. After the reaction was complete, the resulting polymer solution was repeatedly precipitated in n-hexane and filtered to obtain a yellow substance. This substance was dried in a vacuum oven for 24 h to obtain an amphiphilic fluorinated block polymer.

[0028] 0.24 g of an amphiphilic fluorinated block polymer and 0.24 g of sodium undecenoate were dissolved in 22 g of deionized water. Then, a mixture of hexafluorobutyl methacrylate (9 g) and vinyltrimethoxysilane (3 g) was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. The emulsion was then transferred to a 100 ml three-necked flask, and potassium persulfate (0.05 g) was added. The mixture was reacted for 4 h under a nitrogen atmosphere, condensation, and water bath at a temperature of 70 °C to finally obtain an aqueous fluorinated emulsion.

[0029] The scanning electron microscope image of the aqueous fluorinated emulsion prepared in Example 1 is shown below. Figure 6 As shown; from Figure 6 As can be seen, the dispersed spherical particles are uniformly distributed with a narrow particle size distribution, verifying the uniformity of the structure. The aqueous fluorinated emulsion prepared in Example 1 was diluted with water to concentrations of 2.5, 5, 7.5, and 10 g / L, respectively; the zeta potential diagrams of the aqueous fluorinated emulsion at different dilution concentrations are shown below. Figure 7 The above; from Figure 7 As can be seen from the results, the zeta potential measurements of the emulsion at different dilution concentrations (2.5, 5, 7.5, 10 g / L) show that the absolute values ​​are relatively high (all greater than 60 mV), which confirms that the emulsion system has good colloidal stability.

[0030] Example 2 Acrylic acid (3.00 g), azobisisobutyronitrile (0.045 g), and S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide (0.3 g) were dissolved in 20 ml of 1,4-dioxane, and then transferred to a 100 ml three-necked flask. The mixture was reacted for 6 h under nitrogen purging, condensation, and a 70 °C water bath. After the above reaction was completed, azobisisobutyronitrile (0.105 g) was dissolved in trifluoroethyl methacrylate (7 g) and added to the flask to continue the reaction for 12 h. After the reaction was completed, the resulting polymer solution was repeatedly precipitated in n-hexane and filtered to obtain a yellow substance, which was dried in a vacuum oven for 24 h to obtain an amphiphilic fluorinated block polymer.

[0031] 0.24 g of an amphiphilic fluorinated block polymer and 0.24 g of sodium undecenoate were dissolved in 108 g of deionized water. Then, a mixture of hexafluorobutyl methacrylate (9 g) and vinyltrimethoxysilane (3 g) was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. The emulsion was then transferred to a 100 ml three-necked flask, and potassium persulfate (0.05 g) was added. The mixture was reacted for 4 h under a nitrogen atmosphere, condensation, and water bath at a temperature of 70 °C to finally obtain an aqueous fluorinated emulsion.

[0032] Testing showed that the aqueous fluorinated emulsion prepared in this example has good stability.

[0033] Example 3 Acrylic acid (3.00 g), azobisisobutyronitrile (0.045 g), and S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide (0.3 g) were dissolved in 20 ml of 1,4-dioxane in a certain proportion, and then transferred to a 100 ml three-necked flask. The mixture was reacted for 6 h under nitrogen purging, condensation, and water bath conditions at a reaction temperature of 70 °C. After the above reaction was completed, azobisisobutyronitrile (0.105 g) was dissolved in trifluoroethyl methacrylate (7 g) and added to the flask to continue the reaction for 12 h. After the reaction was completed, the resulting polymer solution was repeatedly precipitated in n-hexane and filtered to obtain a yellow substance, which was dried in a vacuum oven for 24 h to obtain an amphiphilic fluorinated block polymer.

[0034] 0.24 g of an amphiphilic fluorinated block polymer and 0.24 g of sodium undecenoate were dissolved in 48 g of deionized water. Then, a mixture of hexafluorobutyl methacrylate (9 g) and vinyltrimethoxysilane (3 g) was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. The emulsion was then transferred to a 100 ml three-necked flask, and potassium persulfate (0.05 g) was added. The mixture was reacted for 4 h under a nitrogen atmosphere, condensation, and water bath at a temperature of 70 °C to finally obtain an aqueous fluorinated emulsion.

[0035] Testing showed that the aqueous fluorinated emulsion prepared in this example has good stability.

[0036] Example 4 Acrylic acid (3.00 g), azobisisobutyronitrile (0.045 g), and S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide (0.3 g) were dissolved in 20 ml of 1,4-dioxane in a certain proportion, and then transferred to a 100 ml three-necked flask. The mixture was reacted for 6 h under nitrogen purging, condensation, and water bath conditions at a reaction temperature of 70 °C. After the above reaction was completed, azobisisobutyronitrile (0.105 g) was dissolved in trifluoroethyl methacrylate (7 g) and added to the flask to continue the reaction for 12 h. After the reaction was completed, the resulting polymer solution was repeatedly precipitated in n-hexane and filtered to obtain a yellow substance, which was dried in a vacuum oven for 24 h to obtain an amphiphilic fluorinated block polymer.

[0037] 0.24 g of an amphiphilic fluorinated block polymer and 0.24 g of sodium undecenoate were dissolved in 18 g of deionized water. Then, a mixture of hexafluorobutyl methacrylate (9 g) and vinyltrimethoxysilane (3 g) was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. The emulsion was then transferred to a 100 ml three-necked flask, and potassium persulfate (0.05 g) was added. The mixture was reacted for 4 h under a nitrogen atmosphere, condensation, and water bath at a temperature of 70 °C to finally obtain an aqueous fluorinated emulsion.

[0038] Testing showed that the aqueous fluorinated emulsion prepared in this example has good stability.

[0039] Example 5 Acrylic acid (3.00 g), azobisisobutyronitrile (0.045 g), and S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide (0.3 g) were dissolved in 20 ml of 1,4-dioxane in a certain proportion, and then transferred to a 100 ml three-necked flask. The mixture was reacted for 6 h under nitrogen purging, condensation, and water bath conditions at a reaction temperature of 70 °C. After the above reaction was completed, azobisisobutyronitrile (0.105 g) was dissolved in trifluoroethyl methacrylate (7 g) and added to the flask to continue the reaction for 12 h. After the reaction was completed, the resulting polymer solution was repeatedly precipitated in n-hexane and filtered to obtain a yellow substance, which was dried in a vacuum oven for 24 h to obtain an amphiphilic fluorinated block polymer.

[0040] 0.24 g of an amphiphilic fluorinated block polymer and 0.24 g of sodium undecenoate were dissolved in 22 g of deionized water. Then, a mixture of hexafluorobutyl methacrylate (10.5 g) and vinyltrimethoxysilane (1.5 g) was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. The emulsion was then transferred to a 100 ml three-necked flask, and potassium persulfate (0.05 g) was added. The mixture was reacted for 4 h under a nitrogen atmosphere, condensation, and water bath at a temperature of 70 °C to finally obtain an aqueous fluorinated emulsion.

[0041] Example 6 Acrylic acid (3.00 g), azobisisobutyronitrile (0.045 g), and S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide (0.3 g) were dissolved in 20 ml of 1,4-dioxane in a certain proportion, and then transferred to a 100 ml three-necked flask. The mixture was reacted for 6 h under nitrogen purging, condensation, and water bath conditions at a reaction temperature of 70 °C. After the above reaction was completed, azobisisobutyronitrile (0.105 g) was dissolved in trifluoroethyl methacrylate (7 g) and added to the flask to continue the reaction for 12 h. After the reaction was completed, the resulting polymer solution was repeatedly precipitated in n-hexane and filtered to obtain a yellow substance, which was dried in a vacuum oven for 24 h to obtain an amphiphilic fluorinated block polymer.

[0042] 0.24 g of an amphiphilic fluorinated block polymer and 0.24 g of sodium undecenoate were dissolved in 22 g of deionized water. Then, a mixture of hexafluorobutyl methacrylate (7.5 g) and vinyltrimethoxysilane (4.5 g) was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. The emulsion was then transferred to a 100 ml three-necked flask, and potassium persulfate (0.05 g) was added. The mixture was reacted for 4 h under a nitrogen atmosphere, condensation, and water bath at a temperature of 70 °C to finally obtain an aqueous fluorinated emulsion.

[0043] Example 7 Acrylic acid (3.00 g), azobisisobutyronitrile (0.045 g), and S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide (0.3 g) were dissolved in 20 ml of 1,4-dioxane in a certain proportion, and then transferred to a 100 ml three-necked flask. The mixture was reacted for 6 h under nitrogen purging, condensation, and water bath conditions at a reaction temperature of 70 °C. After the above reaction was completed, azobisisobutyronitrile (0.105 g) was dissolved in trifluoroethyl methacrylate (7 g) and added to the flask to continue the reaction for 12 h. After the reaction was completed, the resulting polymer solution was repeatedly precipitated in n-hexane and filtered to obtain a yellow substance, which was dried in a vacuum oven for 24 h to obtain an amphiphilic fluorinated block polymer.

[0044] 0.24 g of an amphiphilic fluorinated block polymer and 0.24 g of sodium undecenoate were dissolved in 22 g of deionized water. Then, a mixture of hexafluorobutyl methacrylate (6 g) and vinyltrimethoxysilane (6 g) oil was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. The emulsion was then transferred to a 100 ml three-necked flask, and potassium persulfate (0.05 g) was added. The mixture was reacted for 4 h under a nitrogen atmosphere, condensation, and water bath at a temperature of 70 °C to finally obtain an aqueous fluorinated emulsion.

[0045] Example 8 Acrylic acid (3.00 g), azobisisobutyronitrile (0.045 g), and S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide (0.3 g) were dissolved in 20 ml of 1,4-dioxane in a certain proportion, and then transferred to a 100 ml three-necked flask. The mixture was reacted for 6 h under nitrogen purging, condensation, and water bath conditions at a reaction temperature of 70 °C. After the above reaction was completed, azobisisobutyronitrile (0.105 g) was dissolved in trifluoroethyl methacrylate (7 g) and added to the flask to continue the reaction for 12 h. After the reaction was completed, the resulting polymer solution was repeatedly precipitated in n-hexane and filtered to obtain a yellow substance, which was dried in a vacuum oven for 24 h to obtain an amphiphilic fluorinated block polymer.

[0046] 0.24 g of an amphiphilic fluorinated block polymer and 0.24 g of sodium undecenoate were dissolved in 22 g of deionized water, and then 12 g of hexafluorobutyl methacrylate was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. The emulsion was then transferred to a 100 ml three-necked flask, and 0.05 g of potassium persulfate was added. The mixture was reacted for 4 h under a nitrogen atmosphere, condensation, and water bath at a reaction temperature of 70 °C to finally obtain an aqueous fluorinated emulsion.

[0047] Example 9 Acrylic acid (3.00 g), azobisisobutyronitrile (0.045 g), and S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide (0.3 g) were dissolved in 20 ml of 1,4-dioxane in a certain proportion, and then transferred to a 100 ml three-necked flask. The mixture was reacted for 6 h under nitrogen purging, condensation, and water bath conditions at a reaction temperature of 70 °C. After the above reaction was completed, azobisisobutyronitrile (0.105 g) was dissolved in trifluoroethyl methacrylate (7 g) and added to the flask to continue the reaction for 12 h. After the reaction was completed, the resulting polymer solution was repeatedly precipitated in n-hexane and filtered to obtain a yellow substance, which was dried in a vacuum oven for 24 h to obtain an amphiphilic fluorinated block polymer.

[0048] 0.24 g of an amphiphilic fluorinated block polymer and 0.24 g of sodium undecenoate were dissolved in 22 g of deionized water. Then, a mixed oil phase of hexafluorobutyl methacrylate (4.8 g), vinyl acetate (2.4 g), and 4-hydroxybutyl vinyl ether (4.8 g) was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. The emulsion was then transferred to a 100 ml three-necked flask, and potassium persulfate (0.05 g) was added. The mixture was reacted for 4 h under a nitrogen atmosphere, condensation, and water bath at a temperature of 70 °C to finally obtain an aqueous fluorinated emulsion.

[0049] Effect Example (a) The amphiphilic fluorinated block polymer was prepared using the method described in Example 1, with the molar ratio of acrylic acid to fluorinated acrylate adjusted to 1:1, 1:1.2, 1:1.4, 1:1.6, and 1:1.8. Characterization was performed using conventional methods such as gel permeation chromatography, broad-spectrum infrared spectroscopy, and nuclear magnetic resonance. Specific results are as follows.

[0050] Figure 1 Gel chromatograms of amphiphilic fluorinated block polymers prepared at different molar ratios are shown. As the molar ratio of AA / TFEMA increases, the overall peak position of the GPC spectrum shifts to the left, and the product is a single peak with a narrow peak shape, indicating that the reaction is relatively complete, the product has high purity, and the molecular weight distribution is narrow, which is consistent with the characteristics of RAFT polymerization.

[0051] Figure 2 Infrared spectra of amphiphilic fluorinated block polymers prepared at different molar ratios are shown. The broad OH stretching peak (3400 - 3200 cm⁻¹) and CO stretching peak (1050 - 1000 cm⁻¹) confirm the presence of PAA, while the sharp ester C=O peak (1740 - 1720 cm⁻¹), CF vibration peak (1380 - 1360 cm⁻¹ and 900 - 850 cm⁻¹) and COC stretching peak (1260 - 1200 cm⁻¹) confirm the presence of PTFEMA.

[0052] Figure 3 The NMR spectra of amphiphilic fluorinated block polymers prepared at different molar ratios are shown. The low field width peak at δ = 12.0 - 13.0 ppm confirms the presence of PAA, while the -CH2 (δ = 4.6 ppm, singlet) connected to -CF3 and the -CH2 in the polymer chain (δ = 1.5-2.0 ppm) indicate the presence of the corresponding PTFEMA structure. The characteristic peak of methyl on the alkyl chain is δ = 0.8-1.2 ppm (3H, -CH3).

[0053] Figure 4 The molecular weight and molecular weight distribution of amphiphilic fluorinated block polymers prepared at different molar ratios; As can be seen from the figure, as the molar ratio of AA / TFEMA increases, the molecular weight of the polymer can reach 15,500, and the molecular weight distribution of the product is relatively narrow.

[0054] (II) Aqueous fluorinated emulsions prepared according to Examples 1, 5, 6, and 7, wherein the ratio of vinyl silane coupling agent to fluorinated acrylate in the oil phase was varied; the ratios of different vinyl silane coupling agents to fluorinated acrylates were 1:3, 1:7, 1:1.67, and 1:1, respectively. Their particle size distribution, etc., were detected using conventional methods. Specific results are as follows.

[0055] Figure 5 The figure shows the particle size distribution of aqueous fluorinated emulsions with different ratios of vinyl silane coupling agent to fluorinated acrylate. It can be seen from the figure that the aqueous fluorinated emulsions prepared with different ratios of vinyl silane coupling agent to fluorinated acrylate all have a uniform particle size distribution.

[0056] Figure 8 The images show the stability of the emulsions prepared in Examples 8, 9, and 1. As can be seen from the images, the different emulsions maintained good dispersion after 60 days of storage at room temperature after polymerization, without any stratification or particle aggregation.

[0057] Figure 9 The film-forming properties of the emulsions prepared in Examples 8, 9, and 1 on a glass plate are shown in the figure. As can be seen from the figure, Example 9 has good film-forming properties on a glass plate, with no cracking or oil seepage.

[0058] Figure 10 The photo shows the waterproof performance of Example 9. As can be seen from the photo, the coating surface showed almost no change after being soaked in water for 24 hours, proving that it has excellent waterproof performance.

[0059] Figure 11 As shown in the chemical resistance of Example 9, the coating surface showed almost no change after being immersed in ethanol, acid (pH=1), and alkali (pH=10) for 24 hours, proving that the coating has excellent chemical resistance.

[0060] Figure 12 The image shows the transparency of the coating prepared in Example 9. As can be seen from the image, the coating prepared according to this invention has excellent transparency.

Claims

1. An amphiphilic fluorinated block polymer, characterized in that, The structural formula of the amphiphilic fluorinated block polymer is: 。 2. A method for preparing the amphiphilic fluorinated block polymer as described in claim 1, characterized in that, Includes the following steps: (1) Mix acrylic acid, chain transfer agent, initiator and organic solvent, and reflux the mixture at a certain temperature; (2) After the above reaction is completed, add the fluorinated acrylate and initiator to the reaction system, and continue the reaction by reflux at a certain temperature; (3) After the reaction is complete, the product is cooled to room temperature, n-hexane is added dropwise, the product is obtained by precipitation, and dried to obtain an amphiphilic fluorinated block polymer.

3. The preparation method according to claim 2, characterized in that, In step (1), the molar ratio of acrylic acid to chain transfer agent is 100:1.32-3.33; the molar ratio of acrylic acid to initiator is 100:1.0-2.5, preferably 100:1.5; the organic solvent accounts for 75% of the total phase by mass; the chain transfer agent is S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid) trisulfide, S,S′-di(1-dodecyl)trithiocarbonate, and S-dodecyl-S″-isopropionic acid. At least one of propionic acid-trithiocarbonate; preferably, the chain transfer agent is S-1-dodecyl-S′-(α,α′-dimethyl-α″-propionic acid)trithioester; the initiator is at least one of sodium persulfate, ammonium persulfate, potassium persulfate, azobisisobutyronitrile, and azobisisobutyramidine hydrochloride; preferably, the initiator is azobisisobutyronitrile; the organic solvent is at least one of 1,4-dioxane, ethanol, and dimethyl carbonate; preferably, the organic solvent is 1,4-dioxane.

4. The preparation method according to claim 2 or 3, characterized in that, In step (1), the reflux condensation reaction is a reflux reaction at a temperature of 60-80℃ for 3-24 hours.

5. The preparation method according to any one of claims 2-4, characterized in that, In step (2), the molar ratio of the fluorinated acrylate to the initiator is 100:1.5; the fluorinated acrylate is at least one of trifluoroethyl methacrylate, hexafluorobutyl methacrylate, and octafluoropentyl methacrylate, preferably trifluoroethyl methacrylate; the initiator is at least one of sodium persulfate, ammonium persulfate, potassium persulfate, azobisisobutyronitrile, and azobisisobutyramidine hydrochloride; preferably, the initiator is azobisisobutyronitrile.

6. The preparation method according to claim 2 or 6, characterized in that, In step (2), the reflux reaction is a reflux reaction at a temperature of 60-80℃ for 3-24 hours.

7. The application of an amphiphilic fluorinated block polymer prepared by the method according to any one of claims 1 or 2-6 in the preparation of aqueous fluorinated emulsions.

8. A method for preparing an aqueous fluorinated emulsion using the amphiphilic fluorinated block polymer obtained by the method according to any one of claims 1 or 2-6, characterized in that, Includes the following steps: (a) The amphiphilic block polymer and sodium undecenoate were dissolved in deionized water, and then the oil phase was added. The mixture was ultrasonically dispersed in an ultrasonic cell disperser for 5 min to obtain a pre-emulsified aqueous emulsion. (b) The pre-emulsified aqueous emulsion is added to an initiator and refluxed under a nitrogen atmosphere and at a certain temperature to obtain an aqueous fluorinated emulsion.

9. The method according to claim 8, characterized in that, In step (a), the mass ratio of the amphiphilic block polymer to sodium undecenoate is 1:0.8-1.4, preferably 1:1; the oil phase is a mixture of fluorinated acrylate or fluorinated acrylate and vinyl silane coupling agent, or a mixture of fluorinated acrylate, vinyl acetate and 4-hydroxybutyl vinyl ether; the fluorinated acrylate is at least one of trifluoroethyl methacrylate, hexafluorobutyl methacrylate, and octafluoropentyl methacrylate; preferably hexafluorobutyl methacrylate; the vinyl silane coupling agent is vinyltrimethoxysilane or vinyltriethoxysilane. The mixture contains at least one of silane and γ-methacryloyloxypropyltrimethoxysilane, preferably vinyltrimethoxysilane as the vinyl silane coupling agent; the mass ratio of the vinyl silane coupling agent to the fluorinated acrylate is 1:1-7; the oil phase accounts for 10-40% of the total oil-water phase; the mass ratio of hexafluorobutyl methacrylate, vinyl acetate, and 4-hydroxybutyl vinyl ether is 1:0.3-0.7:1-1.5; the mass ratio of the fluorinated acrylate, vinyl acetate, and 4-hydroxybutyl vinyl ether is 1:0.3-0.7:0.5-1.

5.

10. The method according to claim 8 or 9, characterized in that, In step (b), the initiator is at least one of sodium persulfate, ammonium persulfate, potassium persulfate, azobisisobutyronitrile, and azobisisobutyramidine hydrochloride, preferably potassium persulfate; the amount of the initiator added accounts for 0.5-1.5 wt% of the total oil phase; the reflux reaction is carried out at 60-80°C for 3-6 hours.

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