Compound surfactant as well as preparation method and application thereof

Abstract

The invention relates to the technical field of surfactants, and particularly discloses a compound surfactant as well as a preparation method and application thereof. Comprising fatty alcohol-polyoxyethylene ether sulfonate and fatty alcohol-polyoxyethylene ether, wherein the structural formula of the fatty alcohol-polyoxyethylene ether sulfonate is as follows: in the # imgabs0 # formula, m is equal to 5-10; n is equal to 8-12; and the structural formula of the fatty alcohol-polyoxyethylene ether is as follows: # imgabs 1 #. The compound surfactant disclosed by the invention has excellent emulsifying property and surface tension reducing capacity, and a fluorine-containing monomer emulsion prepared by utilizing the compound surfactant shows excellent stability.

Description

Technical Field

[0001] The present invention relates to the technical field of surfactants, and in particular to a compound surfactant and a preparation method and application thereof. Background Art

[0002] Perfluoroalkyl (polyfluoroalkyl) surfactants, such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) chemicals, are widely used in fluoropolymer production, chip manufacturing, fire extinguishers, coatings industry, etc. Because it has superior interface properties and chemical inertness than hydrocarbons, it is the most suitable surfactant for synthesizing fluoropolymers, but PFOS has persistent accumulation and is not easily degraded.

[0003] In recent years, several PFOA / PFOS substitutes have emerged as fluorocarbon surfactants. One key approach used by large companies such as DuPont is to shorten the perfluorinated chain; another approach is to reduce the number of carbon fluorine atoms, which replaces the C with hydrogen atoms. 8 The fluorine atoms on certain carbon atoms in the fluorine-containing polymer meet the current environmental protection requirements. It is also possible to introduce heteroatoms into the fluorocarbon chain, or replace the perfluoroalkyl with a fluorinated polyether segment to reduce its bioaccumulation. In addition, an active functional group is designed, which can covalently bond with the polymer main chain during the reaction. This method avoids the harm caused to the environment by small molecule fluorocarbon surfactants. For example, CN101535352A uses a fluorinated polyether acid or its salt with a number average molecular weight of about 800g / mol as the main emulsifier and a silicone surfactant as an auxiliary emulsifier to prepare a fluorinated polymer emulsion with relatively stable performance. CN108863858A invented a new type of fluorinated surfactant, which is a short-chain fluorinated surfactant that is still highly fluorinated and still has bioaccumulation.

[0004] The defect of the above technology is that shortening the perfluorocarbon chain, that is, reducing the number of fluorine carbon atoms, will reduce the hydrophobic segment of the surfactant, resulting in poor surface performance. At the same time, these small molecules containing fluorine fragments still pollute the environment due to their excellent stability in the natural environment. Regardless of the method, since the hydrogen atoms in the fluorine-containing surfactant are replaced by fluorine atoms, this structure makes it persistent in the environment, bioaccumulative and forced migration in the environment, and cannot be degraded in time, which will cause great harm to human health and the ecological environment.

[0005] Therefore, there is an urgent need to design a new non-fluorinated surfactant that can replace fluorinated surfactants. Summary of the invention

[0006] The object of the present invention is to provide a composite surfactant and a preparation method and application thereof. The composite surfactant has excellent emulsification performance and the ability to reduce surface tension, and the fluorine-containing monomer emulsion prepared by using the composite surfactant exhibits excellent stability.

[0007] The present invention is achieved through the following technical solutions:

[0008] A composite surfactant, comprising fatty alcohol polyoxyethylene ether sulfonate and fatty alcohol polyoxyethylene ether;

[0009] Wherein, the structural formula of fatty alcohol polyoxyethylene ether sulfonate is as follows:

[0010]

[0011] Wherein, m = 5-10; n = 8-12;

[0012] The structural formula of fatty alcohol polyoxyethylene ether is as follows:

[0013]

[0014] The fatty alcohol polyoxyethylene ether sulfonate in the composite surfactant of the present invention is a multifunctional anionic surfactant. The embedded polyoxyethylene ether chain makes it have the characteristics of both anionic and nonionic surfactants, and can be used under a wide range of pH conditions, and is mainly characterized by: good detergency, emulsification, dispersibility and calcium soap dispersibility; good foaming power and foam stability; acid and alkali resistance, hard water resistance, high temperature resistance and resistance to oxidants and reducing agents; good compatibility, especially no interference with the performance of cationic surfactants; excellent solubilization performance, suitable for preparing functional transparent products; non-toxic, non-irritating, and easily biodegradable; compounding the fatty alcohol polyoxyethylene ether sulfonate with the nonionic surfactant fatty alcohol polyoxyethylene ether can further enhance the emulsification performance of the surfactant.

[0015] In summary, the composite surfactant of the present invention has excellent emulsifying properties and the ability to reduce surface tension, and the fluorinated monomer emulsion prepared using the composite surfactant exhibits excellent stability.

[0016] In a preferred embodiment, the composition comprises the following components by weight:

[0017] Fatty alcohol polyoxyethylene ether sulfonate 0.1-0.5 parts; fatty alcohol polyoxyethylene ether 0.05-0.3 parts.

[0018] A method for preparing a composite surfactant comprises the following steps:

[0019] S1. Synthesizing fatty alcohol polyoxyethylene ether sulfonate: dissolving fatty alcohol polyoxyethylene ether in a non-protonic solvent, and then sequentially adding a basic catalyst and 1,3-propane sultone to react to obtain fatty alcohol polyoxyethylene ether sulfonate;

[0020] S2. At room temperature and pressure, add fatty alcohol polyoxyethylene ether sulfonate and fatty alcohol polyoxyethylene ether into distilled water according to the mass ratio, put them into ultrasound and stir for 5-10 minutes, and after they are completely dissolved, a composite surfactant is obtained.

[0021] The method for synthesizing fatty alcohol polyoxyethylene ether sulfonate of the present invention is simple to operate, does not require the use of an autoclave, has a high yield, and can avoid the use of transition metal compounds as catalysts. The raw materials used are green and have good degradability, and meet the requirements of green production.

[0022] In a preferred embodiment, in step S1, the aprotic solvent includes at least one of tetrahydrofuran, acetonitrile and 1,4-dioxane.

[0023] In a preferred embodiment, in step S1, the alkaline catalyst includes at least one of sodium hydride, potassium tert-butoxide and n-butyl lithium.

[0024] In a preferred embodiment, in step S1, the mass ratio of fatty alcohol polyoxyethylene ether, alkaline catalyst and 1,3-propane sultone is 10:(0.1-2):(2-8).

[0025] In a preferred embodiment, in step S1, the reaction temperature is 50-80°C.

[0026] The invention discloses an application of a compound surfactant in the preparation of a fluorine-containing acrylate polymer.

[0027] A fluorine-containing acrylate polymer is obtained by carrying out polymerization reaction with fluorine-containing acrylate as raw material and the above-mentioned composite surfactant as emulsifier; the fluorine-containing acrylate comprises at least one of hexafluorobutyl acrylate and tridecafluorobutyl acrylate.

[0028] A method for preparing a fluorine-containing acrylate polymer comprises the following steps: adding a composite surfactant into distilled water, then adding a fluorine-containing acrylate, emulsifying for 20-30 minutes, then adding an initiator, heating to 60-80° C., reacting for a certain time, breaking the emulsion, and obtaining a fluorine-containing acrylate polymer.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] The fatty alcohol polyoxyethylene ether sulfonate in the composite surfactant of the present invention is a multifunctional anionic surfactant; the fatty alcohol polyoxyethylene ether is a nonionic surfactant, both of which are fluorine-free and degradable surfactants; wherein the fatty alcohol polyoxyethylene ether sulfonate has the characteristics of anion and nonion, is a new type of degradable "green" surfactant, can be used in a wide pH range, and has excellent foaming performance, water solubility, solubility, wettability, emulsification, etc. The surfactant can be used in combination with many compounds to significantly reduce the oil-water interfacial tension, and the surfactant can be further improved by compounding with the fatty alcohol polyoxyethylene ether to improve the emulsification performance of the surfactant, and the compounding of the two not only avoids the problem of difficult degradation of the fluorinated surfactant, but also has a good emulsification effect in the polymerization of fluorinated acrylate. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0032] Figure 1 The NMR spectrum of the fatty alcohol polyoxyethylene ether sulfonate prepared in Example 1 of the present invention;

[0033] Figure 2 This is the infrared spectrum of the fluorine-containing acrylate polymer prepared in Example 7 of the present invention. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments. The schematic implementation mode of the present invention and its description are only used to explain the present invention and are not intended to limit the present invention. The embodiments described below are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0035] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present invention. However, it is apparent to those of ordinary skill in the art that these specific details do not have to be employed to practice the present invention. In other embodiments, in order to avoid confusing the present invention, known structures, materials or methods are not specifically described. The materials, instruments and reagents used in the following examples, unless otherwise specified, can be obtained from commercial sources. The technical means used in the examples, unless otherwise specified, are conventional means well known to those skilled in the art.

[0036] In order to avoid the problem that the existing fluorinated surfactants are non-degradable, this embodiment provides a compound surfactant, including the compound surfactant including the following components in parts by weight:

[0037] 0.1-0.5 parts of fatty alcohol polyoxyethylene ether sulfonate; 0.05-0.3 parts of fatty alcohol polyoxyethylene ether;

[0038] Wherein, the structural formula of fatty alcohol polyoxyethylene ether sulfonate is as follows:

[0039]

[0040] Wherein, m = 5-10; n = 8-12;

[0041] The structural formula of fatty alcohol polyoxyethylene ether is as follows:

[0042] Among them, fatty alcohol polyoxyethylene ether is an existing product; fatty alcohol polyoxyethylene ether sulfonate is a new substance synthesized by the method of this embodiment.

[0043] The preparation method of the above-mentioned composite surfactant comprises the following steps:

[0044] S1. Synthesis of fatty alcohol polyoxyethylene ether sulfonate: dissolve fatty alcohol polyoxyethylene ether in a non-protonic solvent, then add a basic catalyst and 1,3-propane sultone in sequence to react to obtain fatty alcohol polyoxyethylene ether sulfonate; the synthesis route is as follows:

[0045]

[0046] The aprotic solvent includes at least one of tetrahydrofuran, acetonitrile and 1,4-dioxane; the alkaline catalyst includes at least one of sodium hydride, potassium tert-butoxide and n-butyl lithium; the mass ratio of fatty alcohol polyoxyethylene ether, alkaline catalyst and 1,3-propane sultone is 10:(0.1-2):(2-8); the reaction temperature is 50-80°C, preferably 60°C.

[0047] In this embodiment, the hydroxyl group of fatty alcohol polyoxyethylene ether is etherified with 1,3-propane sultone to generate a fatty alcohol polyoxyethylene ether sulfonate. By selecting a series of chain lengths of m and n, including m=5-10 and n=8-12, a series of non-fluorinated surfactants with good performance can be obtained.

[0048] S2. At room temperature and pressure, add fatty alcohol polyoxyethylene ether sulfonate and fatty alcohol polyoxyethylene ether into distilled water according to the mass ratio, put them into ultrasound and stir for 5-10 minutes, and after they are completely dissolved, a composite surfactant is obtained.

[0049] Wherein, the mass ratio of fatty alcohol polyoxyethylene ether sulfonate to fatty alcohol polyoxyethylene ether is (0.1-0.5):(0.05-0.3).

[0050] The above-mentioned composite surfactant can be used to prepare fluorine-containing acrylate polymer.

[0051] A fluorine-containing acrylate polymer is obtained by carrying out a polymerization reaction with fluorine-containing acrylate as a raw material and a compound surfactant as an emulsifier; the fluorine-containing acrylate comprises at least one of hexafluorobutyl acrylate and tridecafluorobutyl acrylate.

[0052] A method for preparing a fluorine-containing acrylate polymer comprises the following steps: adding a composite surfactant to distilled water, then adding a fluorine-containing acrylate, emulsifying for 20-30 minutes, then adding an initiator, which may specifically be potassium persulfate, heating to 60-80°C, reacting for a certain period of time, breaking the emulsion, and obtaining a fluorine-containing acrylate polymer.

[0053] The structural formula of fluorinated acrylate is as follows:

[0054]

[0055] In the formula, R 1 For selected C 2 -C 15 A fluorinated alkyl group, such as ethyl, n-butyl, n-hexyl, n-octyl or n-tridecyl, more specifically, R 1 It can be selected from butyl hexafluoroacrylate and butyl tridecafluoroacrylate, and the mass ratio between the two can be 1:1, 2:1, 4:3, 7:3, etc.

[0056] In a preferred case, the preparation method of the fluorine-containing acrylate polymer is as follows: the raw materials are measured by mass: 0.1-0.5 parts of a compound surfactant are added to 10-50 parts of distilled water; 1-8 parts of butyl hexafluoroacrylate and 1-5 parts of butyl tridecafluoroacrylate are added and emulsified for 20-30 minutes, and then 0.01-0.1 parts of an initiator are added, mixed, stirred and heated to 60-80°C, and the emulsion is broken after monitoring the reaction for a certain time to obtain a fluorine-containing acrylate polymer.

[0057] In order to better illustrate the technical effect of this embodiment, the following specific cases are used for illustration:

[0058] Embodiment 1:

[0059] A fatty alcohol polyoxyethylene ether sulfonate, the synthesis process of which is as follows:

[0060] Under nitrogen environment, fatty alcohol polyoxyethylene ether (m = 5, n = 8) (10g) was dissolved in tetrahydrofuran in a round-bottom flask, and sodium hydride (1g) and 1,3-propane sultone (5.2g) were added in sequence. The mixture was reacted at 60°C for 4h to obtain a crude product of fatty alcohol polyoxyethylene ether sulfonate, which was then recrystallized to obtain 12.8g (yield 91%) of the pure product NFS1.

[0061] The NMR spectrum of the fatty alcohol polyoxyethylene ether sulfonate synthesized in this example is as follows Figure 1 As shown in the figure, according to the comparison of the NMR spectrum of the fatty alcohol polyoxyethylene ether raw material and the product spectrum of fatty alcohol polyoxyethylene ether sulfonate, it can be seen that the substance has two more peaks near 3.0 and 2.1 ppm, and a group of O-CH 2 - may be contained in the peak at 3.8ppm, and there is no hydroxyl peak of the raw material, so according to the NMR spectrum, the product has been synthesized.

[0062] Embodiment 2:

[0063] A fatty alcohol polyoxyethylene ether sulfonate, the synthesis process of which is as follows:

[0064] Under nitrogen environment, fatty alcohol polyoxyethylene ether (m=6, n=8) (10g) was dissolved in tetrahydrofuran in a round-bottom flask, and sodium hydride (0.9g) and 1,3-propane sultone (4.6g) were added in sequence. The mixture was reacted at 60°C for 4h to obtain a crude product of fatty alcohol polyoxyethylene ether sulfonate, which was then recrystallized to obtain 10.2g (yield 76%) of pure product NFS2.

[0065] Embodiment 3:

[0066] A fatty alcohol polyoxyethylene ether sulfonate, the synthesis process of which is as follows:

[0067] Under nitrogen environment, fatty alcohol polyoxyethylene ether (m=7, n=8) (10g) was dissolved in tetrahydrofuran in a round-bottom flask, and sodium hydride (0.8g) and 1,3-propane sultone (4.2g) were added in sequence. The mixture was reacted at 60°C for 4h to obtain a crude product of fatty alcohol polyoxyethylene ether sulfonate, which was then recrystallized to obtain 9.3g of the pure product NFS3 (yield: 70%).

[0068] Embodiment 4:

[0069] A compound surfactant is prepared by compounding the fatty alcohol polyoxyethylene ether sulfonate prepared in Example 1 with fatty alcohol polyoxyethylene ether in a mass ratio of 5:1. The compound surfactant of this example is denoted as NFS4.

[0070] The compounding process is as follows:

[0071] The fatty alcohol polyoxyethylene ether sulfonate prepared in Example 1 and fatty alcohol polyoxyethylene ether were compounded at a mass ratio of 5:1 to obtain a mixture, 0.3 g of the mixture was added to a round-bottom flask, and 20 g of water was added to dissolve it.

[0072] Embodiment 5:

[0073] A compound surfactant is prepared by compounding the fatty alcohol polyoxyethylene ether sulfonate prepared in Example 2 with fatty alcohol polyoxyethylene ether in a mass ratio of 5:1. The compound surfactant of this example is denoted as NFS5.

[0074] The compounding process is the same as in Example 4.

[0075] Embodiment 6:

[0076] A compound surfactant is prepared by compounding the fatty alcohol polyoxyethylene ether sulfonate prepared in Example 3 with fatty alcohol polyoxyethylene ether in a mass ratio of 5:1. The compound surfactant of this example is denoted as NFS6.

[0077] The compounding process is the same as in Example 4.

[0078] Embodiment 7:

[0079] A method for preparing a fluorine-containing acrylate polymer.

[0080] 0.3 g of the fatty alcohol polyoxyethylene ether sulfonate prepared in Example 1 was added to a round-bottom flask, 20 g of water was added to dissolve it, 10 g of monomers butyl hexafluoroacrylate and butyl tridecafluoroacrylate (7:3) were added, and emulsified for 30 min. Then 0.06 g of initiator potassium persulfate (KPS) was added, nitrogen was replaced, the temperature was raised to 70°C and the reaction was stopped for about 6 h. After the reaction was completed, it was poured into saturated brine to break the emulsion, and 9.56 g of fluorine-containing acrylate polymer was obtained after breaking the emulsion.

[0081] The infrared spectrum of the fluorinated acrylate polymer polymerized in this example is as follows Figure 2 As shown, according to the infrared spectrum data, at 1183cm -1 There is an absorption peak of CF bond around 1750cm -1 The absorption peak of C=O; the absorption position of double bond stretching vibration of fluorinated acrylate is 1680-1620cm -1 , =CH stretching vibration absorption position is 3100-3010cm -1 However, the infrared spectrum did not show the absorption peak of the carbon-carbon double bond, so according to the infrared spectrum, the product has been synthesized.

[0082] Embodiment 8:

[0083] A method for preparing a fluorine-containing acrylate polymer.

[0084] 0.3 g of the fatty alcohol polyoxyethylene ether sulfonate prepared in Example 2 was added to a round-bottom flask, 20 g of water was added to dissolve it, 10 g of monomers of butyl hexafluoroacrylate and butyl tridecafluoroacrylate (7:3) were added, and emulsified for 30 min. Then, 0.06 g of initiator potassium persulfate (KPS) was added, nitrogen was replaced, the temperature was raised to 70°C, and the reaction was stopped for about 6 h. After the reaction was completed, it was poured into saturated brine to break the emulsification, and 8.9 g of fluorine-containing acrylate polymer was obtained after breaking the emulsification.

[0085] Embodiment 9:

[0086] A method for preparing a fluorine-containing acrylate polymer.

[0087] 0.3 g of the fatty alcohol polyoxyethylene ether sulfonate prepared in Example 3 was added to a round-bottom flask, 20 g of water was added to dissolve it, 10 g of monomers of butyl hexafluoroacrylate and butyl tridecafluoroacrylate (7:3) were added, and emulsified for 30 min. Then, 0.06 g of initiator potassium persulfate (KPS) was added, nitrogen was replaced, the temperature was raised to 70°C, and the reaction was stopped for about 6 h. After the reaction was completed, it was poured into saturated brine for demulsification, and 8.0 g of fluorinated acrylate polymer was obtained after demulsification.

[0088] Embodiment 10:

[0089] A method for preparing a fluorine-containing acrylate polymer, comprising adding 10 g of monomers of butyl hexafluoroacrylate and butyl tridecafluoroacrylate (7:3) to the composite surfactant prepared in Example 4, emulsifying for 30 min, then adding 0.06 g of an initiator potassium persulfate (KPS), replacing nitrogen, raising the temperature to 70 ° C. and reacting for about 6 h to stop the reaction, pouring into saturated saline after the reaction to demulsify, and obtaining 9.89 g of a fluorine-containing acrylate polymer after demulsification.

[0090] Embodiment 11:

[0091] A method for preparing a fluorine-containing acrylate polymer, comprising adding 10 g of monomers of butyl hexafluoroacrylate and butyl tridecafluoroacrylate (7:3) to the composite surfactant prepared in Example 5, emulsifying for 30 min, then adding 0.06 g of an initiator potassium persulfate (KPS), replacing nitrogen, raising the temperature to 70 ° C and reacting for about 6 h to stop the reaction, pouring into saturated saline after the reaction to demulsify, and obtaining 9.50 g of a fluorine-containing acrylate polymer after demulsification.

[0092] Embodiment 12:

[0093] A method for preparing a fluorine-containing acrylate polymer, comprising adding 10 g of monomers of butyl hexafluoroacrylate and butyl tridecafluoroacrylate (7:3) to the composite surfactant prepared in Example 6, emulsifying for 30 min, then adding 0.06 g of initiator potassium persulfate (KPS), replacing nitrogen, raising the temperature to 70 ° C and reacting for about 6 h to stop the reaction, pouring into saturated saline after the reaction to demulsify, and obtaining 9.43 g of a fluorine-containing acrylate polymer after demulsification.

[0094] The test results of surfactant performance are shown in Table 1:

[0095] Table 1

[0096]

[0097] Emulsifying ability: According to the industry standard emulsifying ability test method, measure 40mL of the sample aqueous solution and 40mL of edible oil in a stoppered measuring cylinder and shake them vigorously ten times. Let it stand and observe the time required for 10mL of water phase to precipitate.

[0098] Surface tension measurement: Sigma-700 test equipment was used to test according to GB / T 22237-2008 standard using the Wilhelmy plate method. When the plate enters the liquid, the interaction between the liquid and the plate will generate additional force. The surface tension of the liquid can be calculated using the Young-Laplace equation.

[0099] Demulsification time: Under the conditions of the above embodiments 7-12, the time required from the start of the reaction to the appearance of agglomerated products.

[0100] Total amount of agglomerates: under the conditions of the above-mentioned implementation cases 7-12, the total amount of agglomerates after the reaction is completed.

[0101] From the data in Table 1, we can see that:

[0102] The use of compound surfactants such as NFS4, NFS5, and NFS6 can enhance the emulsification performance and reduce the surface tension of water to 26mN / m. At the same time, it exhibits excellent emulsification effect in the emulsion polymerization of fluorinated monomers, and the resulting emulsion has high stability.

[0103] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A composite surfactant, characterized in that: Including fatty alcohol polyoxyethylene ether sulfonates and fatty alcohol polyoxyethylene ethers; Wherein, the structural formula of the fatty alcohol polyoxyethylene ether sulfonate is as follows: Wherein, m = 5-10; n = 8-12; The structural formula of the fatty alcohol polyoxyethylene ether is as follows:

2. A composite surfactant according to claim 1, characterized in that: The composite surfactant comprises the following components in parts by weight: 0.1-0.5 parts of fatty alcohol polyoxyethylene ether sulfonate; 0.05-0.3 parts of fatty alcohol polyoxyethylene ether.

3. A method for preparing a composite surfactant as claimed in claim 1 or 2, characterized in that: The following steps are involved: S1, synthesizing the fatty alcohol polyoxyethylene ether sulfonate: dissolving the fatty alcohol polyoxyethylene ether in a non-protonic solvent, and then sequentially adding a basic catalyst and 1,3-propane sultone to react to obtain the fatty alcohol polyoxyethylene ether sulfonate; S2. At room temperature and pressure, add the fatty alcohol polyoxyethylene ether sulfonate and the fatty alcohol polyoxyethylene ether into distilled water according to the mass ratio, put them into ultrasound and stir for 5-10 minutes, and after they are completely dissolved, obtain the composite surfactant.

4. The preparation method according to claim 3, characterized in that: In step S1, the aprotic solvent includes at least one of tetrahydrofuran, acetonitrile and 1,4-dioxane.

5. The preparation method according to claim 3, characterized in that: In step S1, the alkaline catalyst includes at least one of sodium hydride, potassium tert-butoxide and n-butyl lithium.

6. The preparation method according to claim 3, characterized in that: In step S1, the mass ratio of the fatty alcohol polyoxyethylene ether, the alkaline catalyst and the 1,3-propane sultone is 10:(0.1-2):(2-8).

7. The preparation method according to claim 3, characterized in that: In step S1, the reaction temperature is 50-80°C.

8. Use of a composite surfactant as claimed in claim 1 or 2 in the preparation of a fluorine-containing acrylate polymer.

9. A fluorinated acrylate polymer, characterized in that: The fluorinated acrylate is obtained by polymerization reaction with fluorinated acrylate as raw material and the compound surfactant as claimed in claim 1 or 2 as emulsifier; the fluorinated acrylate comprises at least one of hexafluorobutyl acrylate and tridecafluorobutyl acrylate.

10. The method for preparing a fluorine-containing acrylate polymer according to claim 9, characterized in that: The composite surfactant is added into distilled water, and then the fluorinated acrylate is added, emulsified for 20-30 minutes, and then an initiator is added, the temperature is raised to 60-80° C., and the reaction is performed for a certain time to break the emulsion, thereby obtaining the fluorinated acrylate polymer.

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