Fluorosilicone rubber as well as preparation method and application thereof

Abstract

The invention relates to the technical field of rubber composite materials, and discloses fluorinated silicone rubber as well as a preparation method and application thereof. The method comprises the following steps: in the presence of a catalyst, carrying out first reaction on a hydrolytic polymerization product of gamma-aminopropyl methyl diethoxy silane and octamethylcyclotetrasiloxane to obtain a first reaction product; and dropwise adding 1, 3, 5-tri (3, 3, 3-trifluoropropyl)-1, 3, 5-trimethylcyclotrisiloxane into the first reaction product, and adding an end-capping reagent to carry out a second reaction after dropwise adding is completed, thereby obtaining the fluorosilicone rubber. According to the fluorosilicone rubber provided by the invention, amino is introduced into a molecular chain, and hydrogen bond interaction can be formed between fluorine and nitrogen; the fluorosilicone rubber is further compounded with assistants such as a nanofiller, the side group fluorine and the amido form a hydrogen bond with the hydroxyl group on the surface of the nanofiller, and the interaction between molecular chains is increased, so that the low-temperature damping performance of the fluorosilicone rubber composite material is improved.

Description

Technical Field

[0001] This invention relates to the field of rubber composite materials technology, specifically to a fluorosilicone rubber, its preparation method, and its applications. Background Technology

[0002] Low-temperature damping rubber materials need to maintain excellent vibration reduction, sealing, and elasticity properties in extreme low-temperature environments, and are widely used in aerospace, polar ships, new energy vehicles, rail transportation, and energy equipment. Therefore, the development of a low-temperature resistant, high-damping rubber material is of great significance.

[0003] Currently, silicone rubber is the most commonly used low-temperature resistant material. Silicone rubber's main chain has a high Si-O bond energy and an amorphous molecular structure, which endows it with excellent heat resistance and weather resistance. Simultaneously, due to the weak intermolecular forces and highly flexible molecular chains, silicone rubber exhibits good low-temperature resistance and is widely used in aerospace, automotive, electronics, industrial deep refrigeration, and engine sealing fields. However, its low-temperature damping performance is poor, making the improvement of silicone rubber's damping performance an important research direction. Chemical modification of silicone rubber through chemical reactions, typically by introducing groups of different polarities or sterically hindered groups into the side chains or ends, can increase the resistance to chain segment movement, thereby achieving a certain degree of improvement in dynamic mechanical properties. This strategy provides an effective way to improve the damping performance of silicone rubber, bringing more possibilities and potential to materials engineering and application fields.

[0004] Based on the above background, there is an urgent need to develop a rubber composite material that combines low-temperature resistance and damping performance to meet the needs of special rubbers under extremely cold conditions. Summary of the Invention

[0005] Because traditional fluorosilicone rubber composites rely on weak interactions between molecular chains and fillers, this offers limited improvement in low-temperature damping performance. To address these issues, this invention proposes a fluorosilicone rubber, its preparation method, and its applications.

[0006] To achieve the above objectives, the first aspect of the present invention provides a fluorosilicone rubber, wherein the fluorosilicone rubber comprises: structural unit A, structural unit B, and structural unit C; wherein structural unit A has the structure shown in formula (1), structural unit B has the structure shown in formula (2), and structural unit C has the structure shown in formula (3).

[0007]

[0008] A second aspect of the present invention provides a method for preparing fluorosilicone rubber according to the first aspect, wherein the method includes the following steps:

[0009] (1) In the presence of a catalyst, the hydrolysis polymerization product of γ-aminopropylmethyldiethoxysilane is reacted with octamethylcyclotetrasiloxane to obtain the first reaction product;

[0010] (2) 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane was added dropwise to the first reaction product. After the addition was complete, a capping agent was added to carry out the second reaction to obtain the fluorosilicone rubber.

[0011] A third aspect of the present invention provides a fluorosilicone rubber obtained according to the preparation method described in the second aspect.

[0012] The fourth aspect of the present invention provides the application of the fluorosilicone rubber described in the first or third aspect in the preparation of fluorosilicone rubber composite materials.

[0013] The fifth aspect of the present invention provides a fluorosilicone rubber composite material, wherein the raw materials of the composite material include the fluorosilicone rubber, reinforcing agent, structuring control agent and crosslinking agent described in the first or third aspect.

[0014] The beneficial technical effects achieved by the present invention through the above technical solution are as follows:

[0015] The fluorosilicone rubber provided by this invention introduces amine groups into the molecular chain, and hydrogen bonds can be formed between fluorine and nitrogen. When further compounded with additives such as nanofillers, the side fluorine and amine groups form hydrogen bonds with the hydroxyl groups on the surface of the nanofillers, which increases the interaction between molecular chains and thus improves the low-temperature damping performance of the fluorosilicone rubber composite material. Attached Figure Description

[0016] Figure 1 These are the NMR spectra of the fluorosilicone rubber prepared in Examples 1-5 of this invention. Detailed Implementation

[0017] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0018] The first aspect of the present invention provides a fluorosilicone rubber, wherein the fluorosilicone rubber comprises: structural unit A, structural unit B and structural unit C; wherein structural unit A has the structure shown in formula (1), structural unit B has the structure shown in formula (2), and structural unit C has the structure shown in formula (3).

[0019]

[0020]

[0021] In some embodiments of the present invention, the structural unit shown in formula (1) can be a structural unit from octamethylcyclotetrasiloxane; the structural unit shown in formula (2) can be a structural unit from 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane; and the structural unit shown in formula (3) can be a structural unit from γ-aminopropylmethyldiethoxysilane.

[0022] In some embodiments of the present invention, the molar ratio of structural unit A to structural unit B is 1-20:1, for example 1:1, 1.05:1, 3.13:1, 4.5:1, 8.8:1, and any value within the range of any two of the above values, preferably 1-10:1.

[0023] In some embodiments of the present invention, the molar ratio of structural unit A to structural unit C is 30-60:1, for example 30:1, 32:1, 35:1, 39:1, 42:1, 45:1, 50:1, 60:1, and any value within the range of any two of the above values, preferably 40:1.

[0024] In some embodiments of the present invention, the number-average molecular weight of the fluorosilicone rubber is 300,000 to 800,000, preferably 550,000 to 750,000.

[0025] In this invention, the number-average molecular weight is determined by GPC testing.

[0026] A second aspect of the present invention provides a method for preparing fluorosilicone rubber according to the first aspect, wherein the method includes the following steps:

[0027] (1) In the presence of a catalyst, the hydrolysis polymerization product of γ-aminopropylmethyldiethoxysilane is reacted with octamethylcyclotetrasiloxane to obtain the first reaction product;

[0028] (2) 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane was added dropwise to the first reaction product. After the addition was complete, a capping agent was added to carry out the second reaction to obtain the fluorosilicone rubber.

[0029] In some embodiments of the present invention, in step (1), the catalyst is selected from at least one of potassium hydroxide, lithium hydroxide, tetramethylammonium hydroxide or its silanol salt.

[0030] In some embodiments of the present invention, the catalyst comprises 0.1-0.5% of the total mass of all reactant monomers. All reactant monomers refer to γ-aminopropylmethyldiethoxysilane, octamethylcyclotetrasiloxane, and 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane.

[0031] In some embodiments of the present invention, the hydrolysis polymerization product of γ-aminopropylmethyldiethoxysilane is prepared by the following method: γ-aminopropylmethyldiethoxysilane and water are reacted at 60-80°C for 2-5 hours in a protective atmosphere to obtain the hydrolysis polymerization product.

[0032] In some embodiments of the present invention, the molar ratio of γ-aminopropylmethyldiethoxysilane to octamethylcyclotetrasiloxane is 1:8-15, for example 1:8, 1:9.8, 1:9.9, 1:10, 1:10.1, 1:12, 1:15, and any value within the range of any two of the above values, preferably 1:10.

[0033] In some embodiments of the present invention, the conditions for the first reaction include: a protective atmosphere; a temperature of 60-100°C, preferably 60-80°C; and a time of 10-60 min, preferably 30 min.

[0034] In some embodiments of the present invention, in step (2), the molar ratio of 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane to octamethylcyclotetrasiloxane is 0.1-1.5:1, for example 0.15:1, 0.3:1, 0.43:1, 1.27:1, 1.33:1, and any value within the range of any two of the above values, preferably 0.15-1.3.

[0035] In some embodiments of the present invention, the capping agent is selected from at least one of hexamethyldisiloxane, octamethyltrisiloxane, and decamethyltetrasiloxane.

[0036] In some embodiments of the present invention, the conditions for the second reaction include: a protective atmosphere; a temperature of 100-130°C, preferably 100-120°C; and a time of 1-5 hours, preferably 1-3 hours.

[0037] According to a particularly preferred embodiment of the present invention, a method for preparing fluorosilicone rubber includes the following steps:

[0038] (1) γ-aminopropylmethyldiethoxysilane and water are heated to 60-80℃ and reacted for 2-5 hours under nitrogen atmosphere. After the reaction is completed, the temperature is raised to 100-130℃ and vacuum is used to remove small molecules and low-boiling substances to obtain the hydrolysis polymerization product of γ-aminopropylmethyldiethoxysilane.

[0039] (2) Dehydrate octamethylcyclotetrasiloxane at 50-100℃ and under vacuum for 1-3 hours; then add the hydrolysis polymerization product and catalyst from step (1) at 60-80℃ under nitrogen atmosphere and react for 30 minutes.

[0040] (3) After the reaction in step (2) is completed, add 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane and end-capping agent dropwise, heat to 100-130℃, and react at atmospheric pressure for 1-5 hours.

[0041] (4) After the reaction is complete, the temperature is raised to 150-180℃ and the unreacted monomers and catalysts are removed under vacuum for 1-6 hours. Then the temperature is cooled to room temperature to obtain fluorosilicone rubber.

[0042] This invention enables the preparation of a series of amination-modified fluorosilicone rubbers by controlling reaction conditions and material ratios. Amine and polar fluoropropyl groups are introduced onto the side groups of the silicone rubber, and the low-temperature damping properties of the silicone rubber are improved through interaction with the hydroxyl groups on the surface of nanofillers.

[0043] A third aspect of the present invention provides a fluorosilicone rubber obtained according to the preparation method described in the second aspect.

[0044] The fourth aspect of the present invention provides the application of the fluorosilicone rubber described in the first or third aspect in the preparation of fluorosilicone rubber composite materials.

[0045] A fifth aspect of this invention provides a fluorosilicone rubber composite material, wherein the raw materials of the composite material include the fluorosilicone rubber described in the first or third aspect, a reinforcing agent, a structure control agent, and a crosslinking agent. The fluorosilicone rubber composite material provided by this invention exhibits excellent low-temperature resistance and good damping and shock absorption functions.

[0046] In some embodiments of the present invention, the reinforcing agent is selected from at least one of silica, carbon black, carbon nanotubes, aramid short fibers, graphene, and MXene.

[0047] In some embodiments of the present invention, the structuring control agent is selected from at least one of hydroxyl silicone oil, hydroxyl fluorosilicone oil, and silicon 69.

[0048] In some embodiments of the present invention, the crosslinking agent is selected from at least one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(2,4-dichlorobenzoyl peroxide), dicumyl peroxide, and di-tert-butylperoxyisopropylbenzene.

[0049] In some embodiments of the present invention, the composite material comprises the following raw materials in parts by weight: 100 parts of fluorosilicone rubber, 10-40 parts of reinforcing agent, 5-10 parts of structure control agent and 0.2-1 parts of crosslinking agent.

[0050] The composite material can be prepared by the following method: fluorosilicone rubber, reinforcing agent, structuring control agent and crosslinking agent are mixed evenly in a mixing device to obtain a uniformly dispersed compound; the obtained compound is vulcanized at a certain temperature and time to obtain a fluorosilicone rubber composite material.

[0051] The present invention will be described in detail below through embodiments.

[0052] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0053] Preparation Example 1

[0054] This example illustrates the preparation of fluorosilicone rubber.

[0055] (1) Add 6.5g (0.034mol) γ-aminopropylmethyldiethoxysilane and 0.6g deionized water to a three-necked flask filled with nitrogen. Heat to 60℃ and react for 4h. After the reaction is completed, heat to 100℃ and remove small molecules and low-boiling substances under vacuum until no bubbles are obtained to obtain the hydrolysis polymerization product.

[0056] (2) Add 100g (0.337mol) of octamethylcyclotetrasiloxane to a three-necked flask and remove water under vacuum at 50°C for 1h; add the hydrolysis polymerization product, purge with nitrogen, raise the temperature to 60°C, add 0.36g of catalyst potassium hydroxide silanol salt, and stir with a stirrer for 30min.

[0057] (3) Then slowly raise the temperature to 100℃ and start adding 24g (0.051mol) of vacuum-dried and dehydrated 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane. After the addition is complete, add the end-capping agent hexamethyldisiloxane and react for 4h.

[0058] (4) After the reaction is complete, the temperature is raised to 150°C and vacuumed for 3 hours to remove small molecules and catalyst, and fluorosilicone rubber with a number average molecular weight of 663869 is obtained.

[0059] Preparation Example 2

[0060] This example illustrates the preparation of fluorosilicone rubber.

[0061] (1) Add 5.85 g (0.031 mol) γ-aminopropylmethyldiethoxysilane and 0.55 g deionized water to a three-necked flask filled with nitrogen. Heat to 65 °C and react for 4 h. After the reaction is complete, heat to 100 °C and remove small molecules and low-boiling substances under vacuum until no bubbles are produced, to obtain the hydrolysis polymerization product.

[0062] (2) Add 90g (0.303mol) of octamethylcyclotetrasiloxane to a three-necked flask and remove water under vacuum at 50°C for 1h; add the hydrolysis polymerization product, purge with nitrogen, raise the temperature to 65°C, add 0.49g of catalyst lithium hydroxide silanol salt, and stir with a stirrer for 30min.

[0063] (3) Then slowly raise the temperature to 105℃ and start adding 42g (0.090mol) of vacuum-dried and dehydrated 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane. After the addition is complete, add the end-capping agent octamethyltrisiloxane and react for 3h.

[0064] (4) After the reaction is complete, the temperature is raised to 150°C and vacuumed for 2 hours to remove small molecules and catalyst, and fluorosilicone rubber with a number average molecular weight of 668223 is obtained.

[0065] Preparation Example 3

[0066] This example illustrates the preparation of fluorosilicone rubber.

[0067] (1) Add 5.2g (0.027mol) γ-aminopropylmethyldiethoxysilane and 0.49g deionized water to a three-necked flask filled with nitrogen. Heat to 70℃ and react for 4h. After the reaction is completed, heat to 110℃ and remove small molecules and low-boiling substances under vacuum until no bubbles are obtained to obtain the hydrolysis polymerization product.

[0068] (2) Add 80g (0.270mol) of octamethylcyclotetrasiloxane to a three-necked flask and remove water under vacuum at 50°C for 1h; add the hydrolysis polymerization product, purge with nitrogen, raise the temperature to 70°C, add 0.57g of the catalyst tetramethylammonium hydroxide silanolate, and stir with the stirrer at the same time for 30min.

[0069] (3) Then slowly raise the temperature to 110℃ and start adding 54g (0.115mol) of vacuum-dried and dehydrated 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane. After the addition is complete, add the end-capping agent decamethyltetrasiloxane and react for 3h.

[0070] (4) After the reaction is complete, the temperature is raised to 160℃ and vacuumed for 2 hours to remove small molecules and catalyst, and fluorosilicone rubber with a number average molecular weight of 716052 is obtained.

[0071] Preparation Example 4

[0072] This example illustrates the preparation of fluorosilicone rubber.

[0073] (1) Add 4.55g (0.024mol) γ-aminopropylmethyldiethoxysilane and 0.43g deionized water to a three-necked flask filled with nitrogen. Heat to 75℃ and react for 4h. After the reaction is completed, heat to 120℃ and remove small molecules and low-boiling substances under vacuum until no bubbles are obtained to obtain the hydrolysis polymerization product.

[0074] (2) Add 70g (0.236mol) of octamethylcyclotetrasiloxane to a three-necked flask and remove water under vacuum at 50°C for 1h; add the hydrolysis polymerization product, purge with nitrogen, raise the temperature to 75°C, add 0.72g of the catalyst tetramethylammonium hydroxide silanolate, and stir with the stirrer at the same time for 30min.

[0075] (3) Then slowly raise the temperature to 115℃ and start adding 140g (0.299mol) of vacuum-dried and dehydrated 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane. After the addition is complete, add the end-capping agent hexamethyldisiloxane and react for 2h.

[0076] (4) After the reaction is complete, the temperature is raised to 160℃ and vacuumed for 3 hours to remove small molecules and catalyst, and fluorosilicone rubber with a number average molecular weight of 624784 is obtained.

[0077] Preparation Example 5

[0078] This example illustrates the preparation of fluorosilicone rubber.

[0079] (1) Add 3.9g (0.020mol) γ-aminopropylmethyldiethoxysilane and 0.37g deionized water to a three-necked flask filled with nitrogen. Heat to 80℃ and react for 4h. After the reaction is completed, heat to 120℃ and remove small molecules and low-boiling substances under vacuum until no bubbles are obtained to obtain the hydrolysis polymerization product.

[0080] (2) Add 60g (0.202mol) of octamethylcyclotetrasiloxane to a three-necked flask and remove water under vacuum at 50°C for 1h; add the hydrolysis polymerization product, purge with nitrogen, raise the temperature to 80°C, add 0.85 mol of the catalyst tetramethylammonium hydroxide siloxane, and stir with the stirrer at the same time for 30min.

[0081] (3) Then slowly raise the temperature to 120℃ and start adding 126g (0.269mol) of vacuum-dried and dehydrated 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane. After the addition is complete, add the end-capping agent octamethyltrisiloxane and react for 2h.

[0082] (4) After the reaction is complete, the temperature is raised to 160℃ and vacuumed for 3 hours to remove small molecules and catalyst, and fluorosilicone rubber with a number average molecular weight of 555854 is obtained.

[0083] Example 1

[0084] 100 parts of fluorosilicone rubber matrix (from Preparation Example 1), 20 parts of silica VN3, and 5 parts of hydroxyl silicone oil were mixed evenly in a two-roll mill, and then 0.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were added to obtain a uniformly dispersed compound. The compound was then vulcanized at 160°C for 15 minutes to obtain a fluorosilicone rubber composite material.

[0085] Example 2

[0086] 100 parts of fluorosilicone rubber matrix (from Preparation Example 2), 25 parts of aramid short fiber, and 6 parts of hydroxyl fluorosilicone oil were mixed evenly in a two-roll mill, and then 0.3 parts of bis(2,4-dichlorobenzoyl) peroxide were added to obtain a uniformly dispersed compound. The compound was then vulcanized at 160°C for 15 minutes to obtain a fluorosilicone rubber composite material.

[0087] Example 3

[0088] 100 parts of fluorosilicone rubber matrix (from Preparation Example 3), 30 parts of graphene, and 10 parts of silicon 69 were mixed evenly in a two-roll mill, and then 0.4 parts of dicumyl peroxide were added to obtain a uniformly dispersed compound. The compound was then vulcanized at 160°C for 15 minutes to obtain a fluorosilicone rubber composite material.

[0089] Example 4

[0090] 100 parts of fluorosilicone rubber matrix (from Preparation Example 4), 35 parts of carbon nanotubes, 5 parts of hydroxyl fluorosilicone oil and 5 parts of hydroxyl silicone oil were mixed evenly in a two-roll mill, and then 1 part of di-tert-butyl peroxide isopropylbenzene was added to obtain a uniformly dispersed compound. The compound was vulcanized at 160°C for 15 minutes to obtain a fluorosilicone rubber composite material.

[0091] Example 5

[0092] 100 parts of fluorosilicone rubber matrix (from Preparation Example 5), 40 parts of MXene, 5 parts of hydroxyl fluorosilicone oil and 5 parts of silicon 69 were mixed evenly in a two-roll mill, and then 0.8 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were added to obtain a uniformly dispersed compound; the compound was vulcanized at 160°C for 15 min to obtain a fluorosilicone rubber composite material.

[0093] Comparative Example 1

[0094] 100g of octamethylcyclotetrasiloxane and 50g of 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane were added to a three-necked flask. After removing water under vacuum at 60°C, 4.5g of tetramethylammonium hydroxide silanolate was added, nitrogen gas was introduced, and the temperature was raised to 100°C for 5 hours. After the reaction was completed, the temperature was raised to 170°C and the reaction was carried out under vacuum for 2 hours to remove small molecules and catalyst, thus obtaining fluorosilicone rubber.

[0095] 100 parts of the above-mentioned fluorosilicone rubber as the matrix, 20 parts of silica VN3, and 5 parts of hydroxyl silicone oil were mixed evenly in a two-roll mill, and then 0.2 parts of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane were added to obtain a uniformly dispersed compound. The compound was then vulcanized at 160°C for 15 minutes to obtain a fluorosilicone rubber composite material.

[0096] Comparative Example 2

[0097] 100g of octamethylcyclotetrasiloxane and 30g of 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane were added to a three-necked flask. After dehydration under vacuum at 60°C, 3.9g of tetramethylammonium hydroxide silanolate was added, and the temperature was raised to 110°C and reacted for 4 hours. After the reaction was completed, the temperature was raised to 170°C and vacuum was applied for 2 hours to remove small molecules and catalyst, yielding fluorosilicone rubber.

[0098] 100 parts of the above-mentioned fluorosilicone rubber as the matrix, 25 parts of aramid short fiber, and 6 parts of hydroxyl fluorosilicone oil were mixed evenly in a two-roll mill, and then 0.3 parts of bis(2,4-dichlorobenzoyl) peroxide were added to obtain a uniformly dispersed compound. The compound was then vulcanized at 160°C for 15 minutes to obtain a fluorosilicone rubber composite material.

[0099] Test Example 1

[0100] Preparation of fluorosilicone rubber prepared in Examples 1-5 1 The H-NMR measurement results are as follows: Figure 1 As shown (Example X refers to Preparation Example X). The chemical shifts corresponding to each group are as follows: 0.07-0.14 ppm is the methyl hydrogen peak in the unit, 0.70-0.76 ppm and 2.01-2.1 ppm are the hydrogen resonance absorption peaks on the fluoropropyl group, and 1.5 ppm is the chemical shift of the amino (-NH2) hydrogen in the molecule.

[0101] Test Example 2

[0102] The glass transition temperature (Tg) and maximum loss factor tanδ of the fluorosilicone rubber composites prepared in Examples 1-5 and Comparative Examples 1-2 were tested.

[0103] The results are shown in Table 1.

[0104] Table 1

[0105]

[0106]

[0107] The damping performance of silicone rubber materials is commonly measured by the loss factor; the greater the loss, the better the damping effect. As shown in Table 1, compared to the comparative example, the fluorosilicone rubber prepared in this invention, after further compounding with nanofillers and other additives, and through vulcanization crosslinking, exhibits an improved loss factor after DMA testing (testing instrument: Mettler DMA100, test conditions: 10Hz, 0.3% dynamic strain, -130℃ to 0℃, heating rate 3℃ / min), thus meeting the requirements for material use in extreme environments.

[0108] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A fluorosilicone rubber, characterized in that, The fluorosilicone rubber comprises: structural unit A, structural unit B, and structural unit C; wherein structural unit A has the structure shown in formula (1), structural unit B has the structure shown in formula (2), and structural unit C has the structure shown in formula (3).

2. The fluorosilicone rubber according to claim 1, wherein, The molar ratio of structural unit A to structural unit B is 1-20:1, preferably 1-10:1; Preferably, the molar ratio of structural unit A to structural unit C is 30-60:1, and more preferably 40:

1.

3. The fluorosilicone rubber according to claim 1 or 2, wherein, The number average molecular weight of the fluorosilicone rubber is 300,000 to 800,000, preferably 550,000 to 750,000.

4. A method for preparing fluorosilicone rubber according to any one of claims 1-3, characterized in that, The method includes the following steps: (1) In the presence of a catalyst, the hydrolysis polymerization product of γ-aminopropylmethyldiethoxysilane is reacted with octamethylcyclotetrasiloxane to obtain the first reaction product; (2) 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane was added dropwise to the first reaction product. After the addition was complete, a capping agent was added to carry out the second reaction to obtain the fluorosilicone rubber.

5. The preparation method according to claim 4, wherein, In step (1), the catalyst is selected from at least one of potassium hydroxide, lithium hydroxide, tetramethylammonium hydroxide or its silanol salt; Preferably, the catalyst comprises 0.1-0.5% of the total mass of all reactants; Preferably, the hydrolysis polymerization product of γ-aminopropylmethyldiethoxysilane is prepared by the following method: γ-aminopropylmethyldiethoxysilane and water are reacted at 60-80°C for 2-5 hours in a protective atmosphere to obtain the hydrolysis polymerization product; Preferably, the molar ratio of γ-aminopropylmethyldiethoxysilane to octamethylcyclotetrasiloxane is 1:8-15, more preferably 1:10; Preferably, the conditions for the first reaction include: a protective atmosphere; a temperature of 60-100°C, preferably 60-80°C; and a time of 10-60 min, preferably 30 min.

6. The preparation method according to claim 4 or 5, wherein, In step (2), the molar ratio of 1,3,5-tris(3,3,3-trifluoropropyl)-1,3,5-trimethylcyclotrisiloxane to octamethylcyclotetrasiloxane is 0.1-1.5:1, preferably 0.15-1.3; Preferably, the end-capping agent is selected from at least one of hexamethyldisiloxane, octamethyltrisiloxane, and decamethyltetrasiloxane; Preferably, the conditions for the second reaction include: a protective atmosphere; a temperature of 100-130°C, preferably 100-120°C; and a time of 1-5 hours, preferably 1-3 hours.

7. A fluorosilicone rubber obtained by the preparation method according to any one of claims 4-6.

8. The use of fluorosilicone rubber according to any one of claims 1-3 and 7 in the preparation of fluorosilicone rubber composites.

9. A fluorosilicone rubber composite material, characterized in that, The raw materials for the composite material include fluorosilicone rubber, reinforcing agent, structure control agent and crosslinking agent as described in any one of claims 1-3 and 7.

10. The fluorosilicone rubber composite material according to claim 9, wherein, The reinforcing agent is selected from at least one of silica, carbon black, carbon nanotubes, aramid short fibers, graphene, and MXene. Preferably, the structuring control agent is selected from at least one of hydroxyl silicone oil, hydroxyl fluorosilicone oil, and silicon 69; Preferably, the crosslinking agent is selected from at least one of 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, bis(2,4-dichlorobenzoyl peroxide), dicumyl peroxide, and di-tert-butylperoxyisopropylbenzene; Preferably, the composite material comprises the following raw materials in parts by weight: 100 parts of fluorosilicone rubber, 10-40 parts of reinforcing agent, 5-10 parts of structure control agent and 0.2-1 parts of crosslinking agent.

Images