A process for the preparation of a hydrophobically modified perfluoroether elastomer

Abstract

The application provides a preparation method of hydrophobic modified perfluoro ether elastomer, and applies to the technical field of perfluoro ether elastomer, and comprises the following steps: S1, mixing fluorine-containing vinyl cross-linkable fluorocarbon surfactant and ethylene glycol monomethyl ether, and stirring to obtain a composite dispersed microemulsion; S2, adding deionized water and vulcanization point monomer to the composite dispersed microemulsion, and stirring to form an emulsion; S3, adding perfluoromethyl vinyl ether and an initiator, and introducing tetrafluoroethylene gas to perform polymerization reaction, so as to obtain a perfluoro ether elastomer emulsion; S4, performing demulsification treatment, washing after acidification by concentrated sulfuric acid, and performing hydrophobic modification, so as to obtain hydrophobic modified perfluoro ether elastomer micro powder; and S5, mixing, mold pressing and secondary vulcanization are sequentially performed on the hydrophobic modified perfluoro ether elastomer micro powder, so as to obtain a hydrophobic modified perfluoro ether elastomer sealing product. According to the application, the perfluoro ether elastomer with low viscosity can be prepared, and the pollution of the fluorine-containing surfactant to the environment is reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of fluorine elastomer manufacturing, in particular to a preparation method of hydrophobic modified perfluoroether elastomer. BACKGROUND

[0002] In the process of fluorine elastomer preparation, a surfactant needs to be used to improve the dispersibility of the emulsion and avoid agglomeration in the process of emulsion polymerization. Fluorocarbon surfactants are widely used in the fields of chemical industry, textile and coating due to their excellent surface activity, heat stability and chemical stability. However, traditional long-chain fluorocarbon surfactants such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are difficult to degrade and have biological accumulation, and have been listed as persistent organic pollutants, so their production and use are strictly limited. Therefore, it is urgent to develop new environmentally friendly fluorocarbon surfactants.

[0003] Although the existing short-chain fluorocarbon surfactants such as C4 and C6 products have low toxicity, their surface activity is insufficient and it is difficult to meet the requirements of industrial application.

[0004] Therefore, the application provides a new technical scheme. SUMMARY

[0005] Therefore, the application provides a new technical scheme.

[0006] The application provides the following technical scheme: a preparation method of hydrophobic modified perfluoroether elastomer, comprising the following steps:

[0007] S1, mixing fluorine-containing vinyl cross-linkable fluorocarbon surfactant and ethylene glycol monomethyl ether according to a mass ratio of 2:1-4, stirring to obtain a composite dispersion microemulsion, wherein the structure of the fluorine-containing vinyl cross-linkable fluorocarbon surfactant is CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-Y, CF2=CF-CF2-O-CF(CF3)-CF2-O-CF(CF3)-Y, wherein Y is -SO3M or -COOM, and M is -NH4 or an alkali metal;

[0008] S2, adding deionized water and 30-40 parts by mass of a vulcanization point monomer to 50-80 parts by mass of the composite dispersion microemulsion, and stirring to form an emulsion;

[0009] S3, performing vacuum extraction treatment on the emulsion, adding perfluoromethyl vinyl ether and an initiator, and introducing tetrafluoroethylene gas to perform polymerization reaction, so as to obtain a perfluoroether elastomer emulsion;

[0010] S4, demulsifying the perfluoroether elastomer emulsion, washing after acidification by concentrated sulfuric acid, and vacuum drying to obtain perfluoroether elastomer micro powder, and hydrophobically modifying the perfluoroether elastomer micro powder to obtain hydrophobically modified perfluoroether elastomer micro powder;

[0011] S5, mixing, mold pressing and secondary vulcanization in sequence to obtain the hydrophobically modified perfluoroether elastomer sealing product.

[0012] Optionally, in S1, the structure of the ethylene glycol monomethyl ether is CH3O(CH2CH2O) n H, wherein n = 1-3.

[0013] Optionally, in S3, the tetrafluoroethylene is 47-64% of the mass of the perfluoroether elastomer, and the perfluoromethyl vinyl ether is 35-52% of the mass of the perfluoroether elastomer.

[0014] Optionally, in S3, the initiator is one of persulfate, perfluorobutyryl peroxide, dibenzoyl peroxide and azobisisobutyronitrile.

[0015] Optionally, in S3, the amount of the initiator added is 20-50 parts by mass.

[0016] Optionally, in S3, the vulcanization point monomer is perfluoro-8-cyano-5-methyl-3,6-dioxa-1-octene (8-CNVE).

[0017] Optionally, in S4, the hydrophobic modification includes trifluoromethylation (-CF3) or formamidation (-CONH2).

[0018] Optionally, in S3, when the monomer conversion rate of the polymerization reaction reaches 20-30%, 30-50 parts by mass of a chain transfer agent and 20-60 parts by mass of a fluorine-containing vinyl crosslinkable fluorocarbon surfactant are added.

[0019] Optionally, in S3, the chain transfer agent is selected from one or more of dibromodifluoromethane, dibromotetrafluoroethane, methyl iodide, 1,2-diiodoethane, 1,3-diiodoperfluoropropane and 1,4-diiodoperfluorobutane.

[0020] Compared with the prior art, the above at least one technical solution adopted by the embodiments of the present application can achieve the beneficial effects at least including:

[0021] The technical solution of the present application provides a fluorine-containing vinyl crosslinkable fluorocarbon surfactant and ethylene glycol monomethyl ether hybrid surfactant system, the fluorine-containing vinyl fluorocarbon surfactant participates in polymerization, the auxiliary surfactant is easy to separate after the completion of the polymerization reaction, and acidification and surface hydrophobic modification are performed after demulsification, while the end group passivation is completed, and a low viscosity perfluoroether elastomer is obtained.

[0022] More than 95% of the fluorine-containing vinyl cross-linkable fluorocarbon surfactant in the application participates in the polymerization reaction, and the residual amount in water is less than 5%, reducing the residual amount of surfactant, and the ethylene glycol monomethyl ether does not contain fluorine, reducing the harm to the environment. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions of the embodiments of the application, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and those skilled in the art can also obtain other embodiments according to the drawings disclosed in the specification without creative labor.

[0024] Figure 1 The flowchart of the preparation method of the hydrophobic modified perfluoroether elastomer of the application is shown in the figure.

[0025] Figure 2 The molecular structure of the perfluoroether elastomer synthesized by the fluorine-containing vinyl cross-linkable fluorocarbon surfactant hybrid system of the application is shown in the figure. DETAILED DESCRIPTION

[0026] The embodiments of the application will be described in detail below with reference to the drawings.

[0027] The embodiments of the application will be described in detail below with reference to the drawings.

[0028] It should be noted that the various aspects of the embodiments described below are within the scope of the appended claims. It should be apparent that the aspects described herein can be embodied in a wide variety of forms and that any specific structure and / or function described herein is merely illustrative. Based on the teachings herein one skilled in the art should appreciate that an aspect described herein can be implemented independently of any other aspects and that an aspect described herein can be implemented both as any claim and over multiple claims. In addition, the examples described below are intended to cover any and all modifications.

[0029] In the process of preparing fluorine elastomer, surfactants are needed to be used to improve the dispersibility of emulsion and avoid agglomeration in the process of emulsion polymerization. Fluorocarbon surfactants are widely used in chemical industry, textile, coating and other fields due to their excellent surface activity, heat stability and chemical stability. However, traditional long-chain fluorocarbon surfactants such as perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS) are difficult to degrade and have biological accumulation, and have been listed as persistent organic pollutants. Their production and use are strictly limited. Therefore, it is urgent to develop new environmentally friendly fluorocarbon surfactants.

[0030] Although the existing short-chain fluorocarbon surfactants such as C4 and C6 products have lower toxicity, their surface activity is insufficient and it is difficult to meet the needs of industrial applications.

[0031] Therefore, the embodiment of the present specification proposes a preparation method of hydrophobically modified perfluoroether elastomer, which comprises,

[0032] S1, mixing fluorine-containing vinyl cross-linkable fluorocarbon surfactant and ethylene glycol monomethyl ether according to a mass ratio of 2:1-4, stirring to obtain a composite dispersion microemulsion;

[0033] S2, adding 50-80 parts by mass of the composite dispersion microemulsion, 25000-30000 parts by mass of deionized water, and 30-40 parts by mass of a vulcanization point monomer, and stirring to form an emulsion;

[0034] S3, vacuumizing the emulsion, adding perfluoromethyl vinyl ether and an initiator, and introducing tetrafluoroethylene gas to carry out polymerization reaction, to obtain a perfluoroether elastomer emulsion;

[0035] S4, demulsifying the perfluoroether elastomer emulsion, washing after acidification with concentrated sulfuric acid, and vacuum drying to obtain perfluoroether elastomer micro powder, and hydrophobically modifying the perfluoroether elastomer micro powder to obtain hydrophobically modified perfluoroether elastomer micro powder;

[0036] S5, mixing, mold pressing and secondary vulcanization of the hydrophobically modified perfluoroether elastomer micro powder in sequence to obtain a hydrophobically modified perfluoroether elastomer sealing product.

[0037] In S1, the structure of the fluorine-containing vinyl cross-linkable fluorocarbon surfactant is CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-Y, CF2=CF-CF2-O-CF(CF3)-CF2-O-CF(CF3)-Y, wherein Y is -SO3M or -COOM, and M is -NH4 or an alkali metal.

[0038] The structure of ethylene glycol monomethyl ether is CH3O(CH2CH2O) n H, wherein n=1-3.

[0039] In S3, the tetrafluoroethylene is 47-64% by mass of the perfluoroether elastomer, and the perfluoromethyl vinyl ether (PMVE) is 35-52% by mass of the perfluoroether elastomer. The initiator is one of persulfate, perfluorobutyryl peroxide, dibenzoyl peroxide, and azobisisobutyronitrile, the persulfate is sodium persulfate or potassium persulfate, and the amount of the initiator added is 20-50 parts by mass.

[0040] The vulcanization point monomer is perfluoro-8-cyano-5-methyl-3,6-dioxa-1-octene (8-CNVE). When the monomer conversion rate of the polymerization reaction reaches 20-30%, 30-50 parts by mass of a chain transfer agent and 20-60 parts by mass of a fluorine-containing vinyl crosslinkable fluorocarbon surfactant are added. The chain transfer agent is one or more selected from the group consisting of dibromodifluoromethane, dibromotetrafluoroethane, methyl iodide, 1,2-diiodoethane, 1,3-diiodoperfluoropropane, and 1,4-diiodoperfluorobutane.

[0041] In S4, the demulsification can be performed by the method shown in Example 1 of the specification with the application number CN202411081988.9. The hydrophobic modification includes trifluoromethylation (-CF3) or formamidation (-CONH2).

[0042] In the technical solution of the present application, to avoid introducing impurities, the water used is deionized water unless otherwise specified.

[0043] The preparation method of the fluorine-containing vinyl crosslinkable fluorocarbon surfactant in the embodiments of the present application is specifically as follows: CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-SO3Na, CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-COONa, and CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-COO-NH4. See the patent US3282875A and the paper Preparation of a Fluorocarbon Polymerizable Surfactant and Its Application in Emulsion Polymerization of Fluorine-Containing Acrylate, Polymers 2017, 9, 606, https: / / doi.org / 10.3390 / polym9110606.

[0044] Example 1

[0045] A preparation method of a hydrophobically modified perfluoroether elastomer, comprising

[0046] S1, stirring CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-SO3Na and CH3O(CH2CH2O)2H at a mass ratio of 1:1 at a stirring speed of 15000 r / min for 1.0 h to obtain a composite dispersion microemulsion;

[0047] S2, adding 10 L deionized water and 35 g vulcanization point monomer to 60 g of the composite dispersion microemulsion, the vulcanization point monomer being perfluoro-8-cyano-5-methyl-3,6-dioxa-1-octene (8-CNVE), stirring at a stirring speed of 50 r / min for 20 min to form an emulsion;

[0048] S3, vacuumizing the emulsion to reduce the oxygen content to below 10 ppm, adding 400 g of perfluoromethyl vinyl ether and 30 g of dibenzoyl peroxide, and introducing 400 g of tetrafluoroethylene gas to perform a polymerization reaction, wherein tetrafluoroethylene is added to maintain a constant pressure every time the pressure drops by 0.05 MPa during the reaction, to obtain a perfluoroether elastomer emulsion, when the monomer conversion rate of the polymerization reaction reaches 25%, adding 40 g of 1,4-diiodoperfluorobutane chain transfer agent and 40 g of CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-SO3Na;

[0049] S4, demulsifying the perfluoroether elastomer emulsion, washing after acidification with concentrated sulfuric acid, and vacuum drying to obtain perfluoroether elastomer micro powder, and hydrophobically modifying the perfluoroether elastomer micro powder, specifically, using trifluoromethylation hydrophobic modification, i.e. reacting the perfluoroether elastomer micro powder with sulfur tetrafluoride (SF4) and anhydrous hydrogen fluoride (HF) under a nitrogen atmosphere, the reaction temperature being 100 ℃ and the reaction time being 20 min, the concentration of SF4 and HF both being 10 wt%, to perform hydrophobic modification, to obtain hydrophobically modified perfluoroether elastomer micro powder;

[0050] S5, mixing, mold pressing and secondary vulcanization the hydrophobically modified perfluoroether elastomer micro powder in sequence to obtain a hydrophobically modified perfluoroether elastomer sealing product.

[0051] Example 2

[0052] A method for preparing a hydrophobically modified perfluoroether elastomer, comprising

[0053] S1, stirring CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-COONa and CH3O(CH2CH2O)H at a mass ratio of 2:1 at a stirring speed of 15000 r / min for 1.0 h to obtain a composite dispersion microemulsion;

[0054] S2, 8 L of deionized water and 30 g of a vulcanization point monomer, i.e., perfluoro-8-cyano-5-methyl-3,6-dioxa-1-octene (8-CNVE), are added to 50 g of the composite dispersion microemulsion, and stirring is performed at a rotation speed of 50 r / min for 20 min to form an emulsion;

[0055] S3, vacuum treatment is performed on the emulsion, the oxygen content is reduced to below 10 ppm, 340 g of perfluoromethyl vinyl ether and 20 g of sodium persulfate are added, and 550 g of tetrafluoroethylene gas is introduced for polymerization reaction, and during the reaction process, tetrafluoroethylene is supplemented every time the pressure drops by 0.05 MPa to maintain a constant pressure, and a perfluoroether elastomer emulsion is obtained, when the monomer conversion rate of the polymerization reaction reaches 20%, 30 g of iodo-methane chain transfer agent and 40 g of CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-COONa are added;

[0056] S4, demulsification treatment is performed on the perfluoroether elastomer emulsion, and after acidification by concentrated sulfuric acid, washing and vacuum drying are performed, and perfluoroether elastomer micro powder is obtained, and the perfluoroether elastomer micro powder is subjected to hydrophobic modification, specifically, tri-fluoromethylation hydrophobic modification is adopted, that is, the perfluoroether elastomer micro powder is reacted with sulfur tetrafluoride (SF4) and anhydrous hydrogen fluoride (HF) in a nitrogen atmosphere, the reaction temperature is 100 ℃, the reaction time is 20 min, the concentration of SF4 and HF is 10 wt%, and the hydrophobic modification is performed to obtain hydrophobically modified perfluoroether elastomer micro powder, and the hydrophobically modified perfluoroether elastomer micro powder is obtained;

[0057] S5, the hydrophobically modified perfluoroether elastomer micro powder is sequentially subjected to mixing, mold pressing and secondary vulcanization to obtain a hydrophobically modified perfluoroether elastomer sealing product.

[0058] Example 3

[0059] A method for preparing a hydrophobically modified perfluoroether elastomer, comprising

[0060] S1, CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-COO-NH4 and CH3O(CH2CH2O)3H are stirred at a rotation speed of 15000 r / min for 1.0 h according to a mass ratio of 1:2 to obtain a composite dispersion microemulsion;

[0061] S2, 30 L of deionized water and 40 g of a vulcanization point monomer, i.e., perfluoro-8-cyano-5-methyl-3,6-dioxa-1-octene (8-CNVE), are added to 80 g of the composite dispersion microemulsion, and stirring is performed at a rotation speed of 50 r / min for 20 min to form an emulsion;

[0062] S3, vacuumizing the emulsion, reducing the oxygen content to below 10 ppm, adding 550 g of perfluoromethyl vinyl ether and 50 g of azobisisobutyronitrile, and introducing 350 g of tetrafluoroethylene gas for polymerization reaction, supplementing tetrafluoroethylene gas to maintain constant pressure every time the pressure drops by 0.05 MPa during the reaction, when the monomer conversion rate of the polymerization reaction reaches 30%, adding 60 g of dibromodifluoromethane chain transfer agent and 60 g of CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-COO-NH4, to obtain a perfluoroether elastomer emulsion;

[0063] S4, demulsifying the perfluoroether elastomer emulsion, washing after acidification with concentrated sulfuric acid, and vacuum drying to obtain perfluoroether elastomer micro powder, hydrophobically modifying the perfluoroether elastomer micro powder, specifically using formamidation hydrophobic modification, i.e. reacting the perfluoroether elastomer micro powder with an aqueous ammonium carbonate solution in a packed bed reactor, the amidation temperature being 80°C, the reaction time being 30 min, and the concentration of the ammonium carbonate being 10 wt%, to obtain hydrophobically modified perfluoroether elastomer micro powder;

[0064] S5, mixing, mold pressing and secondary vulcanization of the hydrophobically modified perfluoroether elastomer micro powder in sequence to obtain a hydrophobically modified perfluoroether elastomer sealing product.

[0065] Comparative Example 1

[0066] Compared with Example 1, CH3O(CH2CH2O)2H is not added, and twice the mass of CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-SO3Na is added in S1.

[0067] During S3, agglomeration occurs, and subsequent experiments cannot be performed.

[0068] The demulsification process in the present application is specifically the process parameters in Example 1 of the company's patent CN118620106B.

[0069] The concentrations of fluorine-containing vinyl surfactant and ethylene glycol monomethyl ether CH3O(CH2CH2O)2H in the residual liquid after flocculation of the perfluoroether elastomer emulsion in Examples 1-3 were determined by HPLC (Shimadzu Nexera LC-20ADXR): 100 mL of residual liquid was dried, methanol was added for Soxhlet extraction, and then determination was performed (mobile phase acetonitrile / 0.05 mol% phosphoric acid buffer (pH 6)=6 / 4).

[0070] Table 1: Comparison of performance parameters of various examples:

[0071] Performance Test Standard Example 1 Example 2 Example 3 Comparative Example 1 Tensile strength, MPa ASTM D412-06a 22.3 19.5 18.4 - Hardness, HA ASTM D2240-2004 75 73 69 - Mass fraction of fluorosurfactant in water after demulsification, % 3.2 4.5 4.1 -

[0072] By comparing Example 1 and Comparative Example 1, it can be seen that the simple addition of fluorine-containing vinyl cross-linkable fluorocarbon surfactant causes emulsion aggregation during the polymerization process, and the elastomer synthesis cannot be carried out.

[0073] The core breakthrough of the method is to construct a fluorine-containing vinyl cross-linkable surfactant-ethylene glycol monomethyl ether hybrid emulsion system (S1 step) Figure 2 , I is the hydrophobic part; in II, -R is the modified hydrophobic functional group, which reduces the emission of pollutants during the synthesis of perfluoroether elastomer:

[0074] 1. The amount of surfactant residue is extremely low

[0075] By introducing a cross-linkable fluorocarbon surfactant containing vinyl (CF2=CF-), it is used as a comonomer to participate in the polymerization reaction of tetrafluoroethylene (TFE) and perfluoromethyl vinyl ether (PMVE). As shown in Table 1, the residual fluorine-containing surfactant in the water body after demulsification is only 3.2-4.5%, and the content of persistent organic pollutants (POPs) is low.

[0076] 2. Green replacement of non-fluorine auxiliary

[0077] Ethylene glycol monomethyl ether CH3O(CH2CH2O) n As an auxiliary emulsifier, H (n=1-3) has double advantages: no fluorine element, excellent biodegradability, and much lower environmental toxicity than perfluorinated compounds. The polyoxyethylene segment enhances the water phase dispersion stability through hydrogen bonding, forms a complex micelle with the fluorine-containing surfactant (S1 step), and solves the problem of insufficient emulsifying capacity of short-chain fluorocarbon surfactants (C4 / C6).

[0078] The key mechanism is that the fluorine-containing vinyl monomer is introduced into the polymer main chain through free radical reaction during polymerization, achieving "self-immobilization" of the surfactant.

[0079] 3. Synergistic effect of hydrophobic modification and end group passivation

[0080] The hydrophobic modification in S4 stage is not only surface treatment, see Figure 2 , but also the key to the performance leap of the material.

[0081] The preparation method successfully reduces the emission of pollutants during the synthesis of perfluoroether elastomer through the design of cross-linkable surfactant, the construction of hybrid emulsion system, and the synergistic effect of reaction and modification.

[0082] In this specification, the same or similar parts between each embodiment are mutually referred to, and each embodiment focuses on the difference from other embodiments. In particular, for the embodiments described later, the description is relatively simple, and the relevant parts refer to the part of the foregoing embodiment.

[0083] The above description is only specific embodiments of the present application, but the protection scope of the present application is not limited thereto, any changes or replacements within the technical scope disclosed by the present application can be easily thought by those skilled in the art, and should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A process for the preparation of a hydrophobically modified perfluoroether elastomer characterized by: Comprising S1, mixing fluorine-containing vinyl cross-linkable fluorocarbon surfactant and ethylene glycol monomethyl ether according to mass ratio of 2:1-4, stirring to obtain composite dispersion microemulsion, the structure of the fluorine-containing vinyl cross-linkable fluorocarbon surfactant is CF2=CF-O-CF(CF3)-CF2-O-CF2-CF2-Y, CF2=CF-CF2-O-CF(CF3)-CF2-O-CF(CF3)-Y, wherein Y is-SO3M or-COOM, M is-NH4 or alkali metal, the structure of the ethylene glycol monomethyl ether is CH3O(CH2CH2O) n H, wherein n=1-3; S2, adding deionized water, vulcanization point monomer 30-40 parts by mass to 50-80 parts by mass of the composite dispersion microemulsion, stirring to form an emulsion; S3, vacuum treatment is carried out on the emulsion, adding perfluoromethyl vinyl ether and initiator, and introducing tetrafluoroethylene gas for polymerization reaction to obtain perfluoroether elastomer emulsion; S4, demulsification treatment is carried out on the perfluoroether elastomer emulsion, washed after acidification with concentrated sulfuric acid, and vacuum dried to obtain perfluoroether elastomer micro powder, the perfluoroether elastomer micro powder is hydrophobically modified to obtain hydrophobically modified perfluoroether elastomer micro powder, the hydrophobic modification of the perfluoroether elastomer micro powder includes trifluoromethylation; S5, the hydrophobically modified perfluoroether elastomer micro powder is sequentially mixed, molded and secondarily vulcanized to obtain a hydrophobically modified perfluoroether elastomer sealing product.

2. The process for preparing a hydrophobically modified perfluoroether elastomer according to claim 1, characterized in that: In S3, the tetrafluoroethylene is 47-64% of the mass of the perfluoroether elastomer, and the perfluoromethyl vinyl ether is 35-52% of the mass of the perfluoroether elastomer.

3. The method for preparing a hydrophobically modified perfluoroether elastomer according to claim 1, characterized in that: In S3, the initiator is one of persulfate, perfluorobutyryl peroxide, dibenzoyl peroxide and azobis isobutyronitrile.

4. The process for preparing a hydrophobically modified perfluoroether elastomer according to claim 3, characterized in that: The addition amount of the initiator is 20-50 parts by mass.

5. The method for preparing a hydrophobically modified perfluoroether elastomer according to claim 1, characterized in that: In S3, the vulcanization point monomer is perfluoro-8-cyano-5-methyl-3,6-dioxa-1-octene.

6. The method for preparing a hydrophobically modified perfluoroether elastomer according to claim 1, characterized in that: In S3, when the monomer conversion rate of the polymerization reaction reaches 20-30%, 30-50 parts by mass of chain transfer agent and 20-60 parts by mass of fluorine-containing vinyl crosslinkable fluorocarbon surfactant are added.

7. The method for preparing a hydrophobically modified perfluoroether elastomer according to claim 6, characterized in that: In S3, the chain transfer agent is selected from one or more of dibromodifluoromethane, dibromotetrafluoroethane, methyl iodide, 1,2-diiodoethane, 1,3-diiodoperfluoropropane and 1,4-diiodoperfluorobutane.

8. The process of claim 1 wherein: In S2, the addition amount of deionized water is 25000-30000 parts by mass.

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