A fluorine-containing monomer, a fluorine-containing silicone rubber, and a method for producing the same

Abstract

This invention relates to the field of polymer synthesis technology, specifically disclosing a fluorinated monomer, a fluorinated silicone rubber, and a method for preparing the same. The fluorinated monomer contains bonds in its structure or can be introduced into the structure of ethyl silicone rubber, thereby improving the rubber's aging resistance and mechanical properties. This invention also discloses the method of introducing a fluorinated monomer into the structure of ethyl silicone rubber to prepare a fluorinated silicone rubber with good aging resistance and mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of high polymer synthesis, in particular to a fluorine-containing monomer, a fluorine-containing silicone rubber and a preparation method thereof. BACKGROUND

[0002] According to the requirements of the space environment, the polar cold environment and the hydrogen fuel cell field on the low-temperature performance of materials, the rubber products must maintain elasticity and sealing performance at ultra-low temperature. At present, only silicone rubber can meet such harsh service requirements, especially in the low-temperature environment of <-100℃, only ethyl silicone rubber can be used for a long time. Ethyl silicone rubber is a polymethylsiloxane side chain methyl group which is substituted by an ethyl group. When the side chain is all ethyl, the glass transition temperature Tg is as low as -145℃. Therefore, polydiethylsiloxane is considered to be the most outstanding low-temperature performance rubber. However, it appears crystallization at about -73℃, and appears crystalline phase transition at -10-20℃, resulting in the material hardening at low temperature and failing to play the low-temperature resistance characteristics. The key factor restricting the low-temperature resistance performance of silicone rubber products is the glass transition temperature and crystallinity of the raw rubber. In order to improve the crystallization behavior of polydiethylsiloxane, people introduce other copolymer units into the molecular backbone to destroy the chain regularity and then destroy the crystallinity.

[0003] The research shows that when the ethyl molar fraction is 10%, the regular structure of the polymethylsiloxane can be destroyed, and the crystallization temperature is obviously reduced, but the crystallization does not completely disappear. When the ethyl molar fraction is 20%, 30% and 40%, there is no crystalline melting transition in the range of-150-0 ℃, and the Tg is-140, -143, -145 and-146 ℃ respectively, that is, the glass transition temperature decreases with the increase of the content of the ethyl chain segment. For the compression cold resistance coefficient, when the ethyl chain segment molar fraction is 10%, the compression cold resistance coefficients of the ethyl silicone rubber at-80 and-100 ℃ are 0.45 and 0.19 respectively, and the low temperature resistance improves with the increase of the content of the ethyl chain segment. When the ethyl chain segment molar fraction increases to 20%, the compression cold resistance coefficients at-80 and-100 ℃ are 0.76 and 0.47 respectively, which shows more excellent low temperature resistance. With the further increase of the content of the ethyl chain segment, the low temperature resistance changes unobviously. It can be seen that the introduction of the ethyl chain segment greatly improves the cold resistance of the silicone rubber. However, the hot air aging test shows that after 100 ℃×72 h hot air aging, the mechanical properties of the ethyl silicone rubber with the ethyl chain segment molar fraction of 10% and 20% change little, but the mechanical properties of the ethyl silicone rubber with the ethyl chain segment molar fraction of 30% decrease obviously, and the mechanical properties of the ethyl silicone rubber with the ethyl chain segment molar fraction of 40% decrease significantly. After 150 ℃×72 h hot air aging, the similar change trend is shown, wherein the silicone rubber vulcanized rubber with the ethyl chain segment molar fraction of 40% is brittle, and the hot aging performance decreases due to the oxidation and fracture of the ethyl side chain in the hot oxygen environment. Therefore, it still faces great challenges to prepare the low temperature resistant silicone rubber with excellent aging resistance and mechanical properties. SUMMARY

[0004] In view of the above problems, a first object of the present application is to provide a fluorine-containing monomer which can be introduced into the structure of ethyl silicone rubber to improve the aging resistance and mechanical properties of the rubber.

[0005] A second object of the present application is to provide a preparation method of the fluorine-containing monomer.

[0006] A third object of the present application is to provide a preparation method of the fluorine-containing silicone rubber.

[0007] A fourth object of the present application is to provide the fluorine-containing silicone rubber prepared by the preparation method of the fluorine-containing silicone rubber.

[0008] The first technical scheme adopted by the present application is a fluorine-containing monomer comprising one of the following compounds:

[0009] (A1), (A2), (A3),

[0010] (A4), (A5), (A6),

[0011] (A7), (A8), (A9),

[0012] (A10), (A11),

[0013] (A12),

[0014] wherein R1and R2are H or a substituent having a carbon number of less than 8; R is one of CH3-CH(F)-CH2-, CH3-CH(F)CH2CH2-, and Ph-CH2-CH(F)-CH3; R4and R5are one of a substituent containing -Si(OEt)2-, a substituent having a linear or branched structure containing a carbon-carbon double bond having a carbon number of ≤ 12, and a substituent containing a terminal Si-O bond; .

[0015] Preferably, the R1and R2are one of a methyl group, an ethyl group, a propyl group, an isopropyl group, and a phenyl group.

[0016] Preferably, the substituent containing -Si(OEt)2- is R1Si(OEt)2-;

[0017] The substituent having a linear or branched structure containing a carbon-carbon double bond having a carbon number of ≤ 12 is one of CH2=CHCH2-, CH2=CHCH(CH3)-, CH2=CHCH2CH2-, CH2=CHC(CH3) 2- , CH2=CHCH2CH2CH2-, CH2=CHCH2CH2CH2CH2-, CH2=C(CH3)CH2CH2-, CH2=C(CH2CH3)CH2CH2-, and CH2=CHCH(Ph)-;

[0018] The substituent containing a terminal Si-O bond is one of R1R2SiH-, R1SiH2-, and R1SiHCl-;

[0019] wherein R1and R2are one of a methyl group, an ethyl group, a propyl group, an isopropyl group, and a phenyl group.

[0020] Preferably, the R6is one of a methyl group, an ethyl group, a propyl group, and a butyl group. ​​

[0021] The second technical solution adopted by the present application is a preparation method of the fluorine-containing monomer as described in the first technical solution, comprising: synthesizing the fluorine-containing monomer as shown in chemical formula A1-A6 and A12 by using a silicon hydride and a Grignard reagent; synthesizing the fluorine-containing monomer as shown in chemical formula A7 by using a Chan reagent; synthesizing the fluorine-containing monomer as shown in chemical formula A8 by using a FLUOLEAD reagent; and synthesizing the fluorine-containing monomer as shown in chemical formula A9 by using an exchange method.

[0022] The third technical solution adopted by the present application is a preparation method of a fluorine-containing silicone rubber, comprising: preparing the fluorine-containing monomer based on the first technical solution by using a direct copolymerization method or a grafting method.

[0023] Preferably, the direct copolymerization method comprises:

[0024] octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, a capping agent as raw materials, adding a catalyst, purging with nitrogen, adding one of the fluorine-containing monomers containing -Si(OEt)2-, -Si(OMe)2-, -Si(OH)2- after warming, and then performing a polymerization reaction; after the polymerization is completed, adding acetic acid and citric acid for stirring overnight, collecting the polymer and drying to obtain the fluorine-containing silicone rubber.

[0025] Preferably, the grafting method comprises:

[0026] octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, a capping agent as raw materials, adding a catalyst, and then adding a Pt catalyst, the fluorine-containing monomer containing a carbon-carbon double bond, and the fluorine-containing monomer containing a bond, and performing mixing at room temperature to obtain the fluorine-containing silicone rubber.

[0027] or octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, hydrogen-containing silicone oil, tetramethyltetravinylcyclotetrasiloxane, a capping agent as raw materials, adding a catalyst, and synthesizing a hydrogen-containing polysiloxane; adding a Pt catalyst, the fluorine-containing monomer containing a carbon-carbon double bond, and the fluorine-containing monomer containing a bond to the hydrogen-containing polysiloxane, and performing mixing at room temperature to obtain the fluorine-containing silicone rubber.

[0028] Preferably, the capping agent is decamethyltetrasiloxane.

[0029] The chemical formula of the catalyst is:

[0030]

[0031] M1, M2, M3 are saturated alkane, including one of CH3CH2-, CH3CH2CH2-, (CH3)2CH-, (CH3)3C-; M4 is saturated alkane, including one of CH3-, CH3CH2-, CH3CH2CH2-.

[0032] The fourth technical solution adopted by the present application is: a fluorine-containing silicone rubber prepared by the preparation method in the third technical solution.

[0033] The beneficial effects of the above technical solution are:

[0034] (1) The fluorine-containing monomer disclosed by the present application can be introduced into the structure of ethyl silicone rubber, thereby improving the aging resistance and mechanical properties of the rubber; that is, the fluorine-containing monomer can be used to prepare low-temperature silicone rubber, which is beneficial to the improvement of the heat-oxidative aging resistance and mechanical properties of ethyl silicone rubber.

[0035] (2) The excellent low-temperature resistance of ethyl silicone rubber depends on the ethyl content in the molecular structure, but the increase of the ethyl content leads to the deterioration of the heat-oxidative aging resistance and mechanical properties of the material, and the introduction of fluorine monomers into the polymer can effectively improve it; the present application synthesizes a series of new fluorine-containing monomers, which are introduced into the polysiloxane structure by copolymerization and grafting to prepare fluorine-containing silicone rubber with different structures. The present application provides beneficial effects and reliable solutions for the preparation of fluorine-containing monomers and fluorine-containing polysiloxane, especially for the synthesis of fluorine-containing ethyl silicone rubber to significantly improve its heat-oxidative aging resistance and mechanical properties. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 The nuclear magnetic resonance comparison chart of ethyl silicone rubber and ethyl fluorosilicone rubber provided by an embodiment of the present application is shown in the following figure:

[0037] Figure 2 The DSC comparison chart of ethyl silicone rubber and ethyl fluorosilicone rubber provided by an embodiment of the present application is shown in the following figure:

[0038] Figure 3 The thermogravimetric comparison chart of ethyl silicone rubber and ethyl fluorosilicone rubber provided by an embodiment of the present application is shown in the following figure. DETAILED DESCRIPTION

[0039] The present application will be further described below through specific embodiments. It should be pointed out that, for those skilled in the art, without departing from the principles of the present application, a number of variations and improvements can be made, which should also be considered as belonging to the protection scope of the present application.

[0040] The contents not described in detail in the specification of the present application belong to the common technical knowledge of those skilled in the art.

[0041] The present application discloses a fluorine-containing monomer, which contains Key or containing , , , Preferred ingredients include Key or containing , , Specifically, the fluorinated monomer is at least one of the following compounds:

[0042] (A1) (A2) (A3)

[0043] (A4) (A5) (A6)

[0044] (A7) (A8) (A9)

[0045] (A10) (A11)

[0046] (A12)

[0047] In this context, R1 and R2 are H or substituents with fewer than 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, phenyl, etc., and they can be the same or different; R is the structure containing F and C obtained after fluorination of R3, i.e., R is CH3-CH(F)-CH2-, CH3-CH(F)CH2CH2-, Ph-CH2-CH(F)-CH3, etc., and R3 is a substituent containing a carbon-carbon double bond (with ≤10 carbon atoms), such as CH2=CH-CH2-, CH2=CHCH2CH2-, Ph-CH2-CH=CH2, etc.

[0048] R4 is a substituent containing -Si(OEt)2-, a substituent containing a carbon-carbon double bond with a straight-chain or branched structure (≤12 carbons), or a terminal substituent containing... The substituents; the substituents containing -Si(OEt)2- are, for example, R1Si(OEt)2-, including PhSi(OEt)2-, MeSi(OEt)2-, EtSi(OEt)2-, PrSi(OEt)2-, etc.; the substituents containing carbon-carbon double bonds with straight-chain or branched structures (carbon number ≤ 12) are, for example, CH2=CHCH2-, CH2=CHCH(CH3)-, CH2=CHCH2CH2-, CH2=CHC(CH3). 2-CH2=CHCH2CH2CH2-, CH2=CHCH2CH2CH2CH2-, CH2=C(CH3)CH2CH2-, CH2=C(CH2CH3)CH2CH2-, CH2=CHCH(Ph)-, etc.; the terminal contains The substituents can be, for example, R1R2SiH-, R1SiH2-, or R1SiHCl-, where R1 and R2 are H or substituents with fewer than 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, phenyl, etc., and can be the same or different.

[0049] R5 has the same structure as R4, that is, R5 is a substituent containing -Si(OEt)2-, a substituent containing a carbon-carbon double bond with a straight-chain or branched structure (≤12 carbons), or a terminal substituent containing... The substituents; the substituents containing -Si(OEt)2- are, for example, R1Si(OEt)2-, including PhSi(OEt)2-, MeSi(OEt)2-, EtSi(OEt)2-, PrSi(OEt)2-, etc.; the substituents containing carbon-carbon double bonds with straight-chain or branched structures (carbon number ≤ 12) are, for example, CH2=CHCH2-, CH2=CHCH(CH3)-, CH2=CHCH2CH2-, CH2=CHC(CH3). 2- CH2=CHCH2CH2CH2-, CH2=CHCH2CH2CH2CH2-, CH2=C(CH3)CH2CH2-, CH2=C(CH2CH3)CH2CH2-, CH2=CHCH(Ph)-, etc.; the terminal contains The substituents can be, for example, R1R2SiH-, R1SiH2-, or R1SiHCl-, where R1 and R2 are H or substituents with fewer than 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, phenyl, etc., and can be the same or different.

[0050] R6 is a linear alkyl substituent, such as methyl, ethyl, propyl, butyl, etc.; R7 is... .

[0051] This invention discloses a method for preparing fluorinated monomers, including synthesizing fluorinated monomers by reacting silane with Grignard reagent and Olah reagent; or synthesizing fluorinated monomers by using Chern reagent and Fluolead reagent; or synthesizing fluorinated monomers by an exchange method; wherein, fluorinated monomers with chemical formulas A1~A6 and A12 can be synthesized by reacting silane with Grignard reagent, and the reaction formula for synthesizing fluorinated monomers by reacting silane with Grignard reagent is shown below:

[0052]

[0053]

[0054] Wherein, R1 and R2 are H or substituents with fewer than 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, phenyl, etc., which may be the same or different; R1 and R2 are preferably one of H, methyl, ethyl, propyl, isopropyl, phenyl; more preferably H, methyl, ethyl, propyl, phenyl; R is the structure containing F and C obtained after fluorination of R3, that is, R is CH3-CH(F)-CH2-, CH3-CH(F)CH2CH2-, Ph-CH2-CH(F)-CH3, etc., and R3 is a substituent containing a carbon-carbon double bond (with ≤10 carbon atoms), such as CH2=CH-CH2-, CH2=CHCH2CH2-, Ph-CH2-CH=CH2, etc.

[0055] Using Château's reagent, fluorine-containing monomers as shown in chemical formula A7 can be synthesized. The reaction formula for synthesizing fluorine-containing monomers using Château's reagent is shown below:

[0056]

[0057] Wherein, R4 is a substituent containing -Si(OEt)2-, a substituent containing a carbon-carbon double bond with a straight-chain or branched structure (≤12 carbons), or a terminal substituent containing... The substituents; the substituents containing -Si(OEt)2- are, for example, R1Si(OEt)2-, including PhSi(OEt)2-, MeSi(OEt)2-, EtSi(OEt)2-, PrSi(OEt)2-, etc.; the substituents containing carbon-carbon double bonds with straight-chain or branched structures (carbon number ≤ 12) are, for example, CH2=CHCH2-, CH2=CHCH(CH3)-, CH2=CHCH2CH2-, CH2=CHC(CH3). 2- CH2=CHCH2CH2CH2-, CH2=CHCH2CH2CH2CH2-, CH2=C(CH3)CH2CH2-, CH2=C(CH2CH3)CH2CH2-, CH2=CHCH(Ph)-, etc.; the terminal contains The substituents are, for example, R1R2SiH-, R1SiH2-, or R1SiHCl-, where R1 and R2 are H or substituents with fewer than 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, phenyl, etc., and they can be the same or different; X is a halogen.

[0058] That is, R4-X can be terminally contained Organic compounds with substituents, where X is a halogen, such as R1R2SiHCl or R1SiH2Cl, R1SiHCl2, where R1 and R2 are H or substituents with fewer than 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, phenyl, etc., which can be the same or different; R1 and R2 are preferably one of H, methyl, ethyl, propyl, isopropyl, phenyl.

[0059] R4-X can also be an organic compound containing a -Si(OEt)2- substituent, with the structure R1Si(OEt)2Cl, such as PhSi(OEt)2Cl, MeSi(OEt)2Cl, EtSi(OEt)2Cl, PrSi(OEt)2Cl, etc.; preferably PhSi(OEt)2Cl, MeSi(OEt)2Cl, or EtSi(OEt)2Cl.

[0060] R4-X can also be organic compounds with carbon-carbon double bonds and straight or branched structures (carbon number ≤ 12), such as CH2=CHCH2Cl, CH2=CHCHClCH3, CH2=CHCH2CH2Cl, CH2=CHCCl(CH3)2, CH2=CHCH2CH2CH2Cl, CH2=CHCH2CH2CH2CH2Cl, CH2=C(CH3)CH2CH2Cl, CH2=C(CH2CH3)CH2CH2Cl, CH2=CHCHCl(Ph), etc.; preferably CH2=CHCH2Cl, CH2=CHCHClCH3, CH2=CHCH2CH2Cl, CH2=CHCCl(CH3)2, CH2=CHCH2CH2CH2CH2Cl, CH2=C(CH3)CH2CH2Cl, CH2=CHCHCl(Ph).

[0061] Fluorine-containing monomers, such as those represented by chemical formula A8, can be synthesized using FLUOLEAD reagent. The reaction formula for synthesizing fluorine-containing monomers using FLUOLEAD reagent is shown below:

[0062]

[0063] Wherein, R5 is a substituent containing -Si(OEt)2-, a substituent containing a carbon-carbon double bond with a straight-chain or branched structure (≤12 carbons), or a terminal substituent containing... The substituents; the substituents containing -Si(OEt)2- are, for example, R1Si(OEt)2-, including PhSi(OEt)2-, MeSi(OEt)2-, EtSi(OEt)2-, PrSi(OEt)2-, etc.; the substituents containing carbon-carbon double bonds with straight-chain or branched structures (carbon number ≤ 12) are, for example, CH2=CHCH2-, CH2=CHCH(CH3)-, CH2=CHCH2CH2-, CH2=CHC(CH3). 2- CH2=CHCH2CH2CH2-, CH2=CHCH2CH2CH2CH2-, CH2=C(CH3)CH2CH2-, CH2=C(CH2CH3)CH2CH2-, CH2=CHCH(Ph)-, etc.; the terminal contains The substituents can be, for example, R1R2SiH-, R1SiH2-, or R1SiHCl-, where R1 and R2 are H or substituents with fewer than 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, phenyl, etc., and can be the same or different.

[0064] That is, R5-OH can be terminally contained Organic compounds with substituents, such as R1R2SiHOH or R1SiH2OH, R1SiHOH2, where R1 and R2 are H or substituents with fewer than 8 carbon atoms, such as methyl, ethyl, propyl, isopropyl, phenyl, etc., which may be the same or different; R1 and R2 are preferably one of H, methyl, ethyl, propyl, isopropyl, phenyl; more preferably H, methyl, ethyl, propyl, phenyl;

[0065] R5-OH can also be an organic compound containing a -Si(OEt)2- substituent, with the structure R1Si(OEt)2OH, such as PhSi(OEt)2OH, MeSi(OEt)2OH, EtSi(OEt)2OH, PrSi(OEt)2OH, etc.; PhSi(OEt)2OH, MeSi(OEt)2OH, and EtSi(OEt)2OH are preferred.

[0066] R5-OH can also be an organic compound (with carbon number ≤ 12) containing a carbon-carbon double bond and having a straight-chain or branched structure, such as CH2=CHCH2CH2OH, CH2=CHCH2CH2CH2OH, CH2=CHCH2CH2CH2CH2OH, CH2=C(CH3)CH2CH2OH, CH2=C(CH2CH3)CH2CH2OH, CH2=C(CH2CH3)CH2CH2CH2CH2OH, CH2=CHCH2CHOH(CH3), CH2=CHCH2CH2CHOH(CH2CH3), CH2=CHCH2CHOH(CH2CH3), CH2=C(Ph)CH2CH2OH, etc.; preferably CH2=CHCH2CH2CH2OH, CH2=CHCH2CH2CH2CH2OH, CH2=C( more Preferred are CH2=CHCH2CH2CH2OH, CH2=CHCH2CH2CH2CH2OH, CH2=C(CH3)CH2CH2OH, CH2=C(CH2CH3)CH2CH2OH, CH2=C(CH2CH3)CH2CH2CH2CH2OH, CH2=CHCH2CHOH(CH3), CH2=C(Ph)CH2CH2OH.

[0067] Fluorine-containing monomers, such as those with chemical formula A9, can be synthesized via an exchange method. The reaction formula for synthesizing fluorine-containing monomers via the exchange method is shown below:

[0068]

[0069] Wherein, R6 is a linear alkyl substituent, such as methyl, ethyl, propyl, butyl, etc., preferably methyl, ethyl, and propyl; R7 is... .

[0070] This invention discloses a method for preparing fluorinated silicone rubber, which is prepared based on fluorinated monomers as described in the first technical solution through direct copolymerization or grafting; wherein, the fluorinated groups in the fluorinated silicone rubber are on the side chain and are connected to the main chain of the fluorinated silicone rubber through Si-C bonds or Si-O bonds;

[0071] Direct copolymerization methods include:

[0072] Using octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (such as decamethyltetrasiloxane) as main raw materials, the molar ratio of methyl:phenyl:ethyl repeating units is adjusted to (10~95):(0~25):(0~45), with the preferred ratio of different repeating units being (10~90):(0~20):(0~35), more preferably (15~85):(0~15):(0~30); the vinyl content is 0.2~1.5%, preferably 0.3~1.3%, more preferably 0.5~1.2%; a catalyst is added, the mixture is purged with nitrogen for 1 hour, heated to 80~120℃ and held for 0.5~1 hour, preferably held at 85~115℃ for 35~ The reaction is carried out for 55 minutes, more preferably for 40 to 50 minutes at 90 to 110°C; one of the fluorinated monomers containing -Si(OEt)2-, -Si(OMe)2-, or -Si(OH)2- in the first technical solution is added, and the molar amount of the fluorinated monomer is adjusted to 1 to 30% of the total amount of (methyl + phenyl + ethyl), preferably 5 to 28%, more preferably 8 to 25%; the reaction temperature is raised to 120 to 170°C and the reaction is continued for 1 to 6 hours, preferably raised to 125 to 165°C and reacted for 1.5 to 5 hours, more preferably raised to 130 to 160°C and reacted for 2 to 4 hours; after polymerization, acetic acid and citric acid are added and stirred overnight, and the polymer is collected and dried in a vacuum oven at 100°C for 12 hours to obtain fluorinated silicone rubber.

[0073] Grafting methods include:

[0074] Using octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) as main raw materials, the molar ratio of methyl:phenyl:ethyl:vinyl units is adjusted to (10~95):(0~25):(0~45):(3~35), with the preferred molar ratio of different units being (10~90):(0~20):(0~35):(3~30), and more preferably (15~85):(0~15):(0~30):(5~25); a catalyst is added to synthesize high-vinylsiloxanes, and the first technical solution containing [a specific ingredient] is added during compounding. Fluorine monomers, regulating vinyl groups and The molar ratio is 0.9~1.05, preferably 0.92~1.04, more preferably 0.94~1.03; Pt catalyst is added simultaneously, and the mixture is kneaded at room temperature for 3~30 min, and then kept at 35~50℃ for 0.5~8 h, preferably kneaded at room temperature for 5~25 min, kept at 38~45℃ for 1~7 h, more preferably kneaded at room temperature for 6~20 min, and kept at 40~45℃ for 1.5~6 h; a fluorinated organosilicon polymer, i.e. fluorinated silicone rubber, is obtained.

[0075] Alternatively, using octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, hydrogen-containing silicone oil, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (such as decamethyltetrasiloxane) as the main raw materials, the molar ratio of methyl:phenyl:ethyl linkages is adjusted to (10~100):(0~25):(0~45), with the preferred molar ratio of different linkages being (10~90):(0~20):(0~35), more preferably (15~85):(0~15):(0~30); a catalyst is added to synthesize hydrogen-containing polysiloxane (hydrogen content 1~35%), with the preferred amount of hydrogen-containing polysiloxane being 3~30%, more preferably 5~25%; during mixing, a fluorinated monomer containing carbon-carbon double bonds and a fluorinated monomer containing carbon-carbon double bonds, as described in the first technical solution, are added. Fluorine-containing monomers with carbon-carbon double bonds, and the regulation of carbon-carbon double bond fluorine-containing monomers with... The molar ratio of the bonds is 0.9~1.05, preferably 0.92~1.04, more preferably 0.94~1.03; Pt catalyst is added simultaneously, and the mixture is kneaded at room temperature for 3~30 min, and then kept at 35~50℃ for 0.5~8 h, preferably kneaded at room temperature for 5~25 min, kept at 38~45℃ for 1~7 h, more preferably kneaded at room temperature for 6~20 min, and kept at 40~45℃ for 1.5~6 h; a fluorinated organosilicon polymer, i.e. fluorinated silicone rubber, is obtained.

[0076] The chemical formulas of the catalysts used in the direct copolymerization and grafting methods are as follows:

[0077]

[0078] Wherein, M1, M2, and M3 are saturated alkanes, including one of CH3CH2-, CH3CH2CH2-, (CH3)2CH-, and (CH3)3C-, preferably CH3CH2-, (CH3)2CH-, and (CH3)3C-, that is, M1, M2, and M3 are, for example, triethylamine, tributylamine, N,N-dimethylbutylamine, decylamine, and dodecylamine; M4 is a saturated alkane, including one of CH3-, CH3CH2-, and CH3CH2CH2-, preferably CH3CH2- and CH3CH2CH2-, that is, M4-OH is, for example, methanol, ethanol, propanol, and isopropanol.

[0079] The catalyst preparation process is as follows:

[0080]

[0081] H—X1 can be hydrogen chloride gas, or it can be bromomethane, hydrogen bromide, or other gases.

[0082] Example 1

[0083] (1) Preparation of fluorine-containing monomers;

[0084] A 500ml dry three-necked flask was purged with high-purity nitrogen and purged three times. 200ml of diethyl ether and (EtO)3SiHCl were added sequentially. Grignard reagent CH2=CHCH3CH2MgBr (1:1) was slowly added in an ice bath. The temperature was gradually raised to 40℃ and the reaction was allowed to proceed for 12 hours. The reaction was then terminated. The mixture was filtered, extracted, and dried sequentially to obtain CH2=CCH3CH2(EtO)2SiH. The mixture was transferred to a 500ml round-bottom flask purged with high-purity nitrogen. 50ml of diethyl ether was added, and Olah reagent (HF / Py) was slowly added. The mixture was allowed to proceed for 12 hours at 15℃. The reaction was then terminated. The mixture was filtered, extracted, and dried sequentially to obtain CH3CFCH3CH2(EtO)2SiH.

[0085] (2) Catalyst preparation;

[0086] 18 mmol of trioctylamine was weighed and uniformly mixed in 180 ml of ethanol solution. Methyl bromide gas was introduced and the pressure was controlled at 0.3 MPa. After reacting for 3 hours, a catalyst intermediate was obtained. The intermediate was then subjected to filtration, purification, washing, concentration, and crystallization. 2 g of the intermediate was weighed and dissolved in 100 ml of ethanol solution. 2 g of NaOH was added and reacted. After the reaction was completed, the intermediate was filtered multiple times to obtain the catalyst. Then, 0.8 g of the catalyst and 40 g of octamethylcyclotetrasiloxane solution were placed in a 100 ml round-bottom flask. After purging with nitrogen three times, the mixture was heated to a certain temperature and reacted for 7 hours to obtain an alkaline gel containing the catalyst. This gel was then stored in a desiccator under a nitrogen atmosphere for later use.

[0087] (3) Preparation of fluorinated polyorganosiloxanes, i.e., preparation of fluorinated silicone rubber;

[0088] In a 1L glass reactor, octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) were added sequentially as the main raw materials. A catalyst was added, wherein the molar ratio of methyl:phenyl:ethyl repeating units was 73:2:25, and the vinyl content was 0.8%. The reactor was purged with nitrogen for 1 hour, heated to 80°C and held for 40 minutes, and CH3CFCH3CH2(EtO)2SiH was added. The molar amount of fluorine monomer was adjusted to 5% of (methyl + phenyl + ethyl). The reaction temperature was increased to 135°C and the reaction was continued for 5 hours. After polymerization, acetic acid and citric acid were added and stirred overnight. The polymer was collected and dried in a vacuum oven at 100°C for 12 hours to obtain the product. Its glass transition temperature was -129°C, and after aging in hot air at 150°C for 72 hours, its mechanical properties decreased by 5%.

[0089] Example 2

[0090] (1) Preparation of fluorine-containing monomers

[0091] A 500ml dry three-necked flask was purged with high-purity nitrogen and purged three times. 200ml of diethyl ether and Et(Me)SiHCl were added sequentially. Grignard reagent CH2=CHCH3CH2MgBr (1:1.2) was slowly added in an ice bath. The temperature was gradually raised to 40℃ and the reaction was carried out for 12 hours. The reaction was terminated. The mixture was filtered, extracted, and dried sequentially to obtain CH2=CCH3CH2Et(Me)SiH. The mixture was transferred to a 500ml round-bottom flask purged with high-purity nitrogen. 50ml of diethyl ether was added, and Olah reagent (HF / Py) was slowly added. The mixture was reacted at 15℃ for 12 hours. The reaction was terminated. The mixture was filtered, extracted, and dried sequentially to obtain CH3CFCH3CH2Et(Me)SiH.

[0092] (2) Catalyst preparation

[0093] 18 mmol of trioctylamine was weighed and uniformly mixed in 180 ml of ethanol solution. Methyl bromide gas was introduced at a controlled pressure of 0.3 MPa, and the reaction was carried out for 3 hours to obtain a catalyst intermediate. This intermediate was then subjected to filtration, purification, washing, concentration, and crystallization. 2 g of the intermediate was weighed and dissolved in 100 ml of ethanol solution, and 2 g of NaOH was added to initiate the reaction. After the reaction was completed, the intermediate was filtered multiple times to obtain the catalyst. Then, 0.8 g of the catalyst and 40 g of octamethylcyclotetrasiloxane solution were placed in a 100 ml round-bottom flask, purged three times with nitrogen, and heated to a certain temperature for 7 hours to obtain an alkaline gel containing the catalyst. This gel was then stored in a desiccator under a nitrogen atmosphere for later use.

[0094] (3) Preparation of fluorinated silicone rubber

[0095] In a 1L glass reactor, octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) were added sequentially as the main raw materials, along with a catalyst. The molar ratio of methyl:phenyl:ethyl:vinyl units was 65:2:25:8. The reactor was purged with nitrogen for 1 hour and heated to 120°C for 5 hours. The resulting polymer was processed on a two-roll mill, and CH3CFCH3CH2Et(Me)SiH was added to adjust the molar ratio of vinyl units to ≡SiH-containing fluorinated monomers to 0.98. A Pt catalyst was added, and the mixture was kneaded at room temperature for 12 minutes, then held at 45°C for 5 hours to obtain a fluorinated organosilicon polymer. Its glass transition temperature was -128°C, and after aging in hot air at 150°C for 72 hours, its mechanical properties decreased by 8%.

[0096] Example 3

[0097] (1) Preparation of fluorine-containing monomers

[0098] A 500ml dry three-necked flask was purged with high-purity nitrogen and purged three times. 200ml of diethyl ether and PhSi(OEt)2Cl were added sequentially. The reagent FO2SCF2COOMe (1:1) was slowly added in an ice bath. The temperature was gradually raised to 40℃ and the reaction was carried out for 12 hours. The reaction was then terminated. PhSi(OEt)2CF3 was obtained by sequential filtration, extraction and drying. The fluorine-containing monomer was obtained by sequential filtration, extraction and drying.

[0099] (2) Catalyst preparation

[0100] 18 mmol of tributylamine was weighed and uniformly mixed in 180 ml of ethanol solution. Methyl bromide gas was introduced at a controlled pressure of 0.3 MPa, and the reaction was carried out for 3 hours to obtain a catalyst intermediate. This intermediate was then subjected to filtration, purification, washing, concentration, and crystallization. 2 g of the intermediate was weighed and dissolved in 100 ml of ethanol solution, and 2 g of NaOH was added to initiate the reaction. After the reaction was completed, the intermediate was filtered multiple times to obtain the catalyst. Then, 0.8 g of the catalyst and 40 g of octamethylcyclotetrasiloxane solution were placed in a 100 ml round-bottom flask, purged three times with nitrogen, and heated to a certain temperature for 7 hours to obtain an alkaline gel containing the catalyst. This gel was then stored in a desiccator under a nitrogen atmosphere for later use.

[0101] (3) Preparation of fluorinated silicone rubber

[0102] In a 1L glass reactor, octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) were added sequentially as the main raw materials. A catalyst was added, wherein the molar ratio of methyl:phenyl:ethyl repeating units was 78:2:20, and the vinyl content was 0.8%. The reactor was purged with nitrogen for 1 hour, heated to 80°C and held for 40 minutes, and PhSi(OEt)₂CF₃ was added. The molar amount of fluorine monomer was adjusted to 10% of (methyl + phenyl + ethyl). The reaction temperature was increased to 135°C and the reaction was continued for 5 hours. After polymerization, acetic acid and citric acid were added and stirred overnight. The polymer was collected and dried in a vacuum oven at 100°C for 12 hours to obtain the product. Its glass transition temperature was -126°C, and after aging in hot air at 150°C for 72 hours, its mechanical properties decreased by 2%.

[0103] Example 4

[0104] (1) Preparation of fluorine-containing monomers

[0105] A 500ml dry three-necked flask was purged with high-purity nitrogen and purged three times. 200ml of diethyl ether and EtSiH2Cl were added sequentially. Grignard reagent Ph-CH-CH=CH2MgBr (1:1.2) was slowly added in an ice bath. The temperature was gradually raised to 40℃ and the reaction was allowed to proceed for 12 hours. The reaction was then terminated. The mixture was filtered, extracted, and dried sequentially to obtain Ph-CH-CH=CH(Et)SiH2. The mixture was transferred to a 500ml round-bottom flask purged with high-purity nitrogen. 50ml of diethyl ether was added, and Olah reagent (HF / Py) was slowly added. The mixture was allowed to proceed for 12 hours at 15℃. The reaction was then terminated. The mixture was filtered, extracted, and dried sequentially to obtain Ph-CH-CH(F)-CH2(Et)SiH2.

[0106] (2) Catalyst preparation

[0107] 18 mmol of trioctylamine was weighed and uniformly mixed in 180 ml of ethanol solution. Methyl bromide gas was introduced at a controlled pressure of 0.3 MPa, and the reaction was carried out for 3 hours to obtain a catalyst intermediate. This intermediate was then subjected to filtration, purification, washing, concentration, and crystallization. 2 g of the intermediate was weighed and dissolved in 100 ml of ethanol solution, and 2 g of NaOH was added to initiate the reaction. After the reaction was completed, the intermediate was filtered multiple times to obtain the catalyst. Then, 0.8 g of the catalyst and 40 g of octamethylcyclotetrasiloxane solution were placed in a 100 ml round-bottom flask, purged three times with nitrogen, and heated to a certain temperature for 7 hours to obtain an alkaline gel containing the catalyst. This gel was then stored in a desiccator under a nitrogen atmosphere for later use.

[0108] (3) Preparation of fluorinated silicone rubber

[0109] In a 1L glass reactor, octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) as the main raw materials were added sequentially, along with a catalyst. The molar ratio of methyl:phenyl:ethyl:vinyl units was 58:2:25:15. The reactor was purged with nitrogen for 1 hour and heated to 120°C for 5 hours. The resulting polymer was processed on a two-roll mill, and Ph-CH-CH(F)-CH2(Et)SiH2 was added to adjust the vinyl units and the content of... The molar ratio of fluorinated monomers was 0.98. A Pt catalyst was added, and the mixture was kneaded at room temperature for 12 minutes, then maintained at 45°C for 5 hours to obtain a fluorinated organosilicon polymer. Its glass transition temperature was -125°C, and after aging in hot air at 150°C for 72 hours, its mechanical properties decreased by 3%.

[0110] Example 5

[0111] (1) Preparation of fluorine-containing monomers

[0112] A 500ml dry three-necked flask was purged with high-purity nitrogen and purged three times. Then, 200ml of diethyl ether and CH2=CHCH2CH2CH2OH were added sequentially. FLUOLEAD reagent (1:1) was slowly added in an ice bath. The temperature was gradually raised to 40℃ and the reaction was carried out for 12 hours. The reaction was then terminated. The mixture was filtered, extracted, and dried sequentially to obtain the fluorinated monomer CH2=CHCH2CH2CH2F.

[0113] (2) Catalyst preparation

[0114] 18 mmol of tributylamine was weighed and uniformly mixed in 180 ml of ethanol solution. Methyl bromide gas was introduced at a controlled pressure of 0.3 MPa, and the reaction was carried out for 3 hours to obtain a catalyst intermediate. This intermediate was then subjected to filtration, purification, washing, concentration, and crystallization. 2 g of the intermediate was weighed and dissolved in 100 ml of ethanol solution, and 2 g of NaOH was added to initiate the reaction. After the reaction was completed, the intermediate was filtered multiple times to obtain the catalyst. Then, 0.8 g of the catalyst and 40 g of octamethylcyclotetrasiloxane solution were placed in a 100 ml round-bottom flask, purged three times with nitrogen, and heated to a certain temperature for 7 hours to obtain an alkaline gel containing the catalyst. This gel was then stored in a desiccator under a nitrogen atmosphere for later use.

[0115] (3) Preparation of fluorinated silicone rubber

[0116] In a 1L glass reactor, octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) were added sequentially as the main raw materials. The molar ratio of methyl:phenyl:ethyl repeating units was 78:2:20, and the vinyl content was 0.8%. A catalyst was added, along with hydrogen-containing silicone oil to adjust the hydrogen content to 12%. The reactor was purged with nitrogen for 1 hour, heated to 125°C, and reacted for 2 hours. The resulting polymer was processed on a two-roll mill, and CH2=CHCH2CH2CH2F was added to adjust the vinyl repeating units. The molar ratio was 0.98, Pt catalyst was added, and the mixture was kneaded at room temperature for 12 min, then kept at 50℃ for 5 h to obtain a fluorinated organosilicon polymer. Its glass transition temperature was -125℃, and its mechanical properties decreased by 6% after aging in hot air at 150℃ for 72 h.

[0117] Example 6

[0118] (1) Preparation of fluorine-containing monomers

[0119] High-purity nitrogen gas was introduced into a 500ml dry three-necked flask and purged three times. 200ml of diethyl ether and Et2SiHOH were added in sequence. Grignard reagent (FLUOLEAD reagent 1:1.2) was slowly added in an ice bath. The temperature was gradually raised to 40℃ and the reaction was carried out for 12 hours. The reaction was then terminated. The mixture was filtered, extracted and dried in sequence to obtain Et2SiHF.

[0120] (2) Catalyst preparation

[0121] 18 mmol of trioctylamine was weighed and uniformly mixed in 180 ml of ethanol solution. Methyl bromide gas was introduced at a controlled pressure of 0.3 MPa, and the reaction was carried out for 3 hours to obtain a catalyst intermediate. This intermediate was then subjected to filtration, purification, washing, concentration, and crystallization. 2 g of the intermediate was weighed and dissolved in 100 ml of ethanol solution, and 2 g of NaOH was added to initiate the reaction. After the reaction was completed, the intermediate was filtered multiple times to obtain the catalyst. Then, 0.8 g of the catalyst and 40 g of octamethylcyclotetrasiloxane solution were placed in a 100 ml round-bottom flask, purged three times with nitrogen, and heated to a certain temperature for 7 hours to obtain an alkaline gel containing the catalyst. This gel was then stored in a desiccator under a nitrogen atmosphere for later use.

[0122] (3) Preparation of fluorinated silicone rubber

[0123] In a 1L glass reactor, octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) as the main raw materials were added sequentially, along with a catalyst. The molar ratio of methyl:phenyl:ethyl:vinyl units was 58:2:30:10. The reactor was purged with nitrogen for 1 hour and heated to 120°C for 5 hours. The resulting polymer was processed on a two-roll mill, and Et2SiHF was added to adjust the vinyl units and the content of... A fluorine monomer molar ratio of 0.99 was used, and a Pt catalyst was added. The mixture was kneaded at room temperature for 30 min, and then kept at 45 °C for 5 h to obtain a fluorinated organosilicon polymer. Its glass transition temperature was -125 °C, and its mechanical properties decreased by 5% after aging in hot air at 150 °C for 72 h.

[0124] Example 7

[0125] (1) Preparation of fluorine-containing monomers

[0126] A 500ml dry three-necked flask was filled with high-purity nitrogen and purged three times. Then, 200ml of tetrahydrofuran, trifluoroethanol and EtSi(OH)3 were added in sequence. An acid catalyst was added and the reaction was carried out for 5 hours. After purification and separation, EtSi(OCH2CF3)(OH)2 was obtained.

[0127] (2) Catalyst preparation

[0128] 18 mmol of tributylamine was weighed and uniformly mixed in 180 ml of ethanol solution. Methyl bromide gas was introduced at a controlled pressure of 0.3 MPa, and the reaction was carried out for 3 hours to obtain a catalyst intermediate. This intermediate was then subjected to filtration, purification, washing, concentration, and crystallization. 2 g of the intermediate was weighed and dissolved in 100 ml of ethanol solution, and 2 g of NaOH was added to initiate the reaction. After the reaction was completed, the intermediate was filtered multiple times to obtain the catalyst. Then, 0.8 g of the catalyst and 40 g of octamethylcyclotetrasiloxane solution were placed in a 100 ml round-bottom flask, purged three times with nitrogen, and heated to a certain temperature for 7 hours to obtain an alkaline gel containing the catalyst. This gel was then stored in a desiccator under a nitrogen atmosphere for later use.

[0129] (3) Preparation of fluorinated silicone rubber

[0130] In a 1L glass reactor, octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) were added sequentially as the main raw materials. A catalyst was added, wherein the molar ratio of methyl:phenyl:ethyl repeating units was 75:5:20, and the vinyl content was 0.8%. The reactor was purged with nitrogen for 1 hour, heated to 80°C and held for 40 minutes, and then EtSi(OCH2CF3)(OH)2 was added to adjust the molar amount of fluorine monomers to 18% of (methyl + phenyl + ethyl). The reaction temperature was increased to 135°C and the reaction was continued for 5 hours. After polymerization, acetic acid and citric acid were added and stirred overnight. The polymer was collected and dried in a vacuum oven at 100°C for 12 hours to obtain the product. Its glass transition temperature was -121°C, and after aging in hot air at 150°C for 72 hours, its mechanical properties decreased by 4%.

[0131] Comparative Example 1

[0132] Comparative Example 1, corresponding to Example 1, was prepared as follows: Octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) were added sequentially to a 1L glass reactor as the main raw materials. The molar ratio of methyl:phenyl:ethyl repeating units was 73:2:25, and the vinyl content was 0.8%. The reactor was purged with nitrogen for 1 hour, heated to 80°C and held for 40 minutes, then the reaction temperature was increased to 135°C and the reaction continued for 5 hours. After polymerization, acetic acid and citric acid were added and stirred overnight. The polymer was collected and dried in a vacuum oven at 100°C for 12 hours to obtain the product. Its glass transition temperature was -130°C, and after aging in hot air at 150°C for 72 hours, its mechanical properties decreased by 23%.

[0133] Comparative Example 2

[0134] Comparative Example 2, corresponding to Example 2, was prepared as follows: Octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) were added sequentially to a 1L glass reactor as the main raw materials. A catalyst was added, wherein the molar ratio of methyl:phenyl:ethyl:vinyl linkages was 65:2:25:8. The reactor was purged with nitrogen for 1 hour and heated to 120°C and held for 5 hours. The resulting polymer was processed on a two-roll mill to obtain an organosilicon polymer. Its glass transition temperature was -129°C, and after aging in hot air at 150°C for 72 hours, its mechanical properties decreased by 32%.

[0135] Comparative Example 3

[0136] Comparative Example 3, corresponding to Example 3, was prepared as follows: Octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) were added sequentially to a 1L glass reactor as the main raw materials. A catalyst was added, wherein the molar ratio of methyl:phenyl:ethyl repeating units was 78:2:20, and the vinyl content was 0.8%. Nitrogen was purged for 1 hour, the temperature was raised to 80°C and held for 40 minutes, the reaction temperature was increased to 135°C, and the reaction continued for 5 hours. After polymerization, acetic acid and citric acid were added and stirred overnight. The polymer was collected and dried in a vacuum oven at 100°C for 12 hours to obtain the product. Its glass transition temperature was -128°C, and after aging in hot air at 150°C for 72 hours, its mechanical properties decreased by 19%.

[0137] Comparative Example 4

[0138] Comparative Example 4, corresponding to Example 4, was prepared as follows: In a 1L glass reactor, octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent (e.g., decamethyltetrasiloxane) were added sequentially as the main raw materials. A catalyst was added, wherein the molar ratio of methyl:phenyl:ethyl:vinyl linkages was 58:2:25:15. Nitrogen was purged for 1 hour, and the temperature was raised to 120°C and held for 5 hours. The mixture was then kneaded at room temperature for 12 minutes and then held at 45°C for 5 hours to obtain the product, which had a glass transition temperature of -133°C. After aging in hot air at 150°C for 72 hours, the mechanical properties decreased by 21%.

[0139] The fluorinated silicone rubbers (i.e., ethyl fluorosilicone rubbers) prepared in Examples 1-7 and the ethyl silicone rubbers prepared in Comparative Examples 1-4 were subjected to NMR, DSC, and thermogravimetric analyses. The obtained data are shown in Table 1. The NMR comparison diagrams of ethyl silicone rubber and ethyl fluorosilicone rubber are shown in Table 1. Figure 1 The DSC comparison charts for ethyl silicone rubber and ethyl fluorosilicone rubber are shown below. Figure 2The thermogravimetric comparison chart of ethyl silicone rubber and ethyl fluorosilicone rubber is shown below. Figure 3 .

[0140] Table 1 Measurement Results

[0141]

[0142] Figure 1 It is ethyl silicone rubber and ethyl fluorosilicone rubber. 1 HNMR spectrum, solvent is deuterated chloroform; from Figure 1 As can be seen from this, the chemical shifts δ=0~0.16 correspond to SiCH3 * The SiCH2*CH3 corresponding to δ=0.44~0.54, the SiCH2CH3* corresponding to δ=0.9~0.96, and the SiCH2*CH3* corresponding to δ=5.7~5.8 are all represented by δ. * =CH2, δ=5.9~6.2 corresponds to SiCH=CH2*; this indicates that the synthesized polymer contains SiCH3, SiCH2CH3 and Si-CH=CH2, and ethyl silicone rubber was successfully synthesized; at the same time, δ=5.6-6.2 is the chemical shift of hydrogen on Si-CH=CH2, and δ=0.7-0.8 and 2.0-2.1 are the chemical shifts of hydrogen at the α and β positions on Si-CH2CH2CF3, respectively, indicating that -CH2CH2CF3 was successfully introduced into ethyl silicone rubber, and ethyl fluorosilicone rubber was successfully synthesized; further verification by NMR integration shows that the actual content is consistent with the feed ratio.

[0143] As shown in Table 1, the Tg of ethyl silicone rubber gradually decreases with the increase of ethyl content. When the ethyl content is 25%, the Tg is close to -130℃, and no crystallization occurs. There are no other transition temperatures. Figure 2 The figures are DSC diagrams of the examples and comparative examples. When fluorine-containing groups are introduced into ethyl styrene silicone rubber, the glass transition temperature of the resulting ethyl fluorostyrene silicone rubber increases. This is because when large fluorine-containing groups are introduced into the main chain or side chain of silicon oxide, they are randomly distributed with dimethylsiloxane, and the proportion of single bonds that can rotate internally on the main chain is relatively reduced. This disrupts the regularity of the general ethyl silicone rubber macromolecule, reduces the flexibility of the molecular chain, and thus increases the glass transition temperature and deteriorates the low-temperature performance.

[0144] like Figure 3 Thermogravimetric analysis (TGA) was performed on ethylstyrene silicone rubber and ethylfluorostyrene silicone rubber. It was found that with increasing ethyl content, the number of dimethyl repeating units decreased, and the overall trend was a decline in high-temperature resistance. (20% ethyl content → T) 50wt% ≈380℃, 25% ethyl content → T 50wt%The temperature is approximately 400 ℃, with an overall temperature above 370 ℃. When fluorine groups are introduced into ethyl styrene silicone rubber, its heat resistance is improved. When the ethyl content is the same, the higher the fluorine content, the stronger the high-temperature performance. At the same time, the mass residual percentage of ethyl silicone rubber is low, close to 0. This is because ethyl silicone rubber undergoes main chain unwinding degradation in a nitrogen atmosphere, causing the main chain to break and producing volatile cyclic low-molecular-weight compounds. Therefore, its weight loss rate is high and the mass residual percentage is relatively low.

[0145] The fluorinated silicone rubber (i.e., ethyl fluorosilicone rubber) prepared in Examples 1-7 and the ethyl silicone rubber prepared in Comparative Examples 1-4 were subjected to thermo-oxidative aging tests according to standard GB / T 9871 2008 (aged at 150℃ for 72h and at 200℃ for 7d, respectively), and the tensile strength retention rate and elongation at break retention rate were determined. The test results are shown in Tables 2 and 3.

[0146] Table 2. Thermo-oxidative aging performance data at 150℃ for 72 hours

[0147]

[0148] Table 3. Thermo-oxidative aging performance data at 200℃ for 7 days

[0149]

[0150] As can be seen from the data in Tables 2 and 3, introducing fluorinated monomers into ethyl silicone rubber can effectively improve the aging resistance and mechanical properties of ethyl silicone rubber; that is, the present invention introduces fluorinated monomers into the structure of ethyl silicone rubber, thereby improving the aging resistance and mechanical properties of the rubber.

[0151] This invention focuses on synthesizing a variety of fluorinated monomers, providing more molecular structures and application ranges for ethyl fluororubber. It also verifies the successful synthesis of ethyl silicone rubber, the initial thermal decomposition temperature and glass transition temperature of the raw rubber, and the heat aging and oxidation resistance of the vulcanized rubber. Furthermore, compared to existing technologies, this invention introduces methyl, phenyl, ethyl, fluorinated groups, and vinyl groups into silicone rubber, preparing a series of ethyl silicone rubbers containing multiple groups in different proportions. Introducing multiple groups into the silicone rubber increases the steric hindrance of the resulting fluorinated silicone rubber, effectively improving its thermal stability, thus giving it better aging resistance and mechanical properties. Simultaneously, the catalyst used in this invention is a self-made novel catalyst, which can effectively reduce the small molecule rings generated during the chain growth stage of anionic ring-opening polymerization, thereby promoting the reaction and increasing the product yield.

[0152] The present invention has been described in detail above with reference to specific embodiments and exemplary examples. These descriptions are exemplary and not exhaustive, and are not limited to the disclosed embodiments; the above descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present invention without departing from the spirit and scope of the present invention, and all such modifications and improvements fall within the scope of the present invention; the scope of protection of the present invention is determined by the appended claims.

Claims

1. A fluorinated monomer, characterized in that, The structure is as follows: （A9） R6 is a linear alkyl substituent.

2. The fluorinated monomer according to claim 1, characterized in that, R6 is one of methyl, ethyl, propyl, and butyl.

3. A method for preparing a fluorinated monomer as described in any one of claims 1-2, characterized in that, The fluorine-containing monomer, as shown in chemical formula A9, was synthesized via an exchange method, with the reaction formula shown below: 。 4. A method for preparing fluorinated silicone rubber, characterized in that, include: Prepared by direct copolymerization of the fluorinated monomer as described in any one of claims 1-2; The direct copolymerization method includes: Using octamethylcyclotetrasiloxane, octaphenylcyclotetrasiloxane, hexaethylcyclotrisiloxane, tetramethyltetravinylcyclotetrasiloxane, and a capping agent as raw materials, a catalyst was added, nitrogen was purged, and the fluorinated monomers were added after heating; the polymerization reaction was carried out by heating; after the polymerization was completed, acetic acid and citric acid were added and stirred overnight, the polymer was collected and dried to obtain fluorinated silicone rubber.

5. The method for preparing fluorinated silicone rubber according to claim 4, characterized in that, The capping agent is decamethyltetrasiloxane; The chemical formula of the catalyst is: Among them, M1, M2, and M3 are one of CH3CH2-, CH3CH2CH2-, (CH3)2CH-, and (CH3)3C-, respectively; M4 is one of CH3-, CH3CH2-, and CH3CH2CH2-.

6. A fluorinated silicone rubber prepared by the method according to claim 4.

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