Dielectric elastomer with high dielectric constant and preparation method and application thereof

Abstract

The invention relates to a dielectric elastomer with a high dielectric constant and a preparation method and application thereof, and belongs to the technical field of dielectric elastomers. According to the scheme, non-polar rubber such as butadiene-isoprene rubber with high double-bond side group content is modified, specifically, a high-dipole-moment polar group is introduced to a butadiene-isoprene rubber molecular chain in a chemical modification mode, and the dielectric elastomer rubber material with a high dielectric constant is obtained; the dielectric constant can be adjusted by adjusting the number of introduced polar groups, and the mechanical property can be adjusted by adjusting the vulcanization process, so that the electrical property and the mechanical property of the butadiene-isoprene rubber dielectric elastomer can be controlled, and the application field of the butadiene-isoprene rubber dielectric elastomer is expanded; in addition, the material further has high elasticity, and has important significance in application of the material in the fields of flexible drivers, soft robots and the like.

Description

Technical Field

[0001] The present application relates to a dielectric elastomer with a high dielectric constant and a preparation method and application thereof, belonging to the technical field of dielectric elastomer materials. Background Art

[0002] Dielectric elastomer (DE) actuators are essentially deformable capacitors. Their basic structure is a sandwich structure formed by coating a layer of flexible electrodes on the upper and lower surfaces of a dielectric elastomer film. When a certain voltage is applied to the flexible electrodes on the upper and lower surfaces of the DE film, electrostatic attraction will occur between the opposite charges on the upper and lower surfaces, while the same charges on the same side will repel each other, causing the DE film to shrink in thickness and expand in plane. It can return to its original shape after power is off, thereby realizing the mutual conversion between electrical energy and mechanical energy.

[0003] Rubber materials have become ideal materials for large-scale preparation of DE due to their excellent resilience and low cost. However, commonly used rubber materials such as butadiene-pentadiene rubber, natural rubber, styrene-butadiene rubber, butyl rubber, etc. have low dielectric constants, resulting in a low electrodeformation of the prepared DE. Therefore, a higher driving voltage needs to be applied, which not only limits the application range of the device but also shortens the service life of the device.

[0004] At present, researchers generally use polar rubbers such as chloroprene rubber and nitrile rubber to prepare DE. However, there is a problem that the higher polar group content on the main chain of the rubber molecule restricts the movement of the molecular chain, which greatly weakens the resilience of the polar rubber. In addition, its dielectric constant still needs to be improved.

[0005] Therefore, providing a DE material with a high dielectric constant, a flexible rubber main chain and good resilience is a technical problem that needs to be solved urgently and is of great significance. Summary of the invention

[0006] In order to solve the above problems, a dielectric elastomer with a high dielectric constant and a preparation method and application thereof are provided. By modifying non-polar rubber such as butadiene-pentadiene rubber with a high double bond side group content, specifically by introducing high dipole moment polar groups on the butadiene-pentadiene rubber molecular chain by chemical modification, a dielectric elastomer rubber material with a high dielectric constant is obtained. The dielectric constant of the butadiene-pentadiene rubber dielectric elastomer can be adjusted by adjusting the number of introduced polar groups, and the mechanical properties of the butadiene-pentadiene rubber dielectric elastomer can be adjusted by adjusting the vulcanization process, thereby achieving control of the electrical and mechanical properties of the butadiene-pentadiene rubber dielectric elastomer, expanding the applicable field of the prepared butadiene-pentadiene rubber dielectric elastomer, which is of great significance for its application in the fields of flexible actuators, soft robots, etc.

[0007] The present application provides a method for preparing a dielectric elastomer with a high dielectric constant, the preparation method comprising the following steps: 1) dissolving butadiene-vinyl rubber in an organic solvent to obtain butadiene-vinyl rubber solution; 2) Adding a halogenating agent to the butyl-pentene rubber solution to carry out a chemical modification reaction; 3) Separating polar butadiene-vinyl rubber from the butadiene-vinyl rubber solution after the reaction; 4) The polar butadiene-pentadiene rubber is vulcanized to obtain the dielectric elastomer with a high dielectric constant.

[0008] In view of the problems existing in dielectric elastomer rubber materials such as chloroprene rubber and nitrile rubber currently used in the prior art, a new dielectric elastomer material of butadiene-butadiene rubber with a high dielectric constant is provided. The new dielectric elastomer material not only has good rebound performance, but also has a high dielectric constant due to the high dipole moment polar groups introduced on its side groups by chemical modification. The dielectric constant is increased by about 41% compared with polar nitrile rubber.

[0009] Based on the chemical modification of butadiene-butadiene rubber, a new dielectric elastomer material with excellent rebound performance, mechanical properties and electrical properties was obtained. Its excellent rebound performance, mechanical properties and high dielectric constant enable it to obtain better rebound performance at a smaller driving voltage as a dielectric elastomer, making it a more ideal dielectric elastomer material than the existing chloroprene rubber and nitrile rubber.

[0010] Optionally, the butadiene-vinyl rubber includes four structural units: 1,2-butadiene, 1,4-butadiene, 3,4-isoprene and 1,4-isoprene; the sum of the amounts of the 1,2-butadiene and 3,4-isoprene substances accounts for more than 40% of the total amount of the four structural unit substances.

[0011] Optionally, the sum of the amounts of the 1,2-butadiene and 3,4-isoprene substances accounts for 40-80% of the total amount of the four structural unit substances.

[0012] The NBR used is a raw NBR with a high content of double bond side groups, such as vinyl and propylene structures. Since the double bonds on the side groups are more active than the double bonds on the main chain, after chemical modification, more polar groups in the NBR are grafted to the side double bonds, thereby avoiding damage to the flexibility of the rubber main chain. Taking sulfonyl chloride in the halogenation reagent as an example, sulfonyl chloride can react with the side double bonds to generate polar chlorine atom groups or ester groups with sulfur atoms.

[0013] The introduced polar functional groups have the following effects: 1) The more polar functional groups introduced, the higher the dielectric constant of the elastomer will be; 2) However, the introduced polar functional groups will reduce the flexibility of the original molecular chain. When the flexibility of the rubber molecular chain is low, the resilience of the modified rubber elastomer will deteriorate; 3) At the same time, introducing too many polar functional groups will reduce the breakdown strength of the rubber material, making it unsuitable for use in high electric field environments. Within a reasonable range, elastic properties, high dielectric constant and high breakdown strength properties can be taken into account at the same time.

[0014] Optionally, the halogenating agent is one or more of N-chlorosuccinimide, sulfonyl chloride, trichloroisocyanuric acid and imidazole chloride ionic liquid.

[0015] It should be noted that, in addition to the halogenating agents listed above, other halogenating agents that can react with double bonds and increase polar groups can achieve the same technical effect of the present application scheme, and by increasing polar groups, a butadiene-vinyl rubber dielectric elastomer with a high dielectric constant can be obtained.

[0016] Optionally, the 1,4-butadiene includes cis-1,4-butadiene and trans-1,4-butadiene, and the 1,4-isoprene includes cis-1,4-isoprene and trans-1,4-isoprene; The sum of the amounts of the cis-1,4-butadiene and cis-1,4-isoprene substances accounts for 50-80% of the total amount of the 1,4-butadiene and 1,4-isoprene substances.

[0017] The above content represents the content of cis structure in the main chain. The higher the content, the more flexible the main chain. Conversely, the higher the content of trans structure, the worse the flexibility. The flexibility of the main chain is beneficial to the rebound performance but not to the tensile strength. The products within the above range can take into account both elasticity and tensile strength.

[0018] Optionally, the molecular weight of the butadiene-pentadiene rubber is 50-100w.

[0019] If the molecular weight of the butadiene-vinyl rubber used is too low, the comprehensive mechanical properties of the product will be reduced. If the molecular weight of the butadiene-vinyl rubber is too high, problems such as extrusion deformation and stress concentration will easily occur in subsequent processing techniques such as extrusion and molding, resulting in poor processing performance.

[0020] Optionally, the molecular weight distribution of the butadiene-pentadiene rubber is 1.0-3.0.

[0021] The molecular weight distribution represents the uniformity of the molecular weight distribution of the butadiene-vinyl rubber. The lower the molecular weight distribution value, the more uniform the molecular weight distribution. When used in a dielectric elastomer, the hysteresis can be reduced, thereby making the rebound performance better, but the processing performance will be slightly worse. The higher the molecular weight distribution value, the more uneven the molecular weight distribution is, which is not conducive to the rebound performance, but is conducive to the processing performance. The butadiene-vinyl rubber within the above range of the present application can take into account both the processing performance and the rebound performance.

[0022] Optionally, the mass ratio of the halogenated reagent to the butadiene-vinyl rubber is (10-50):100. The above ratio affects the degree of modification of the polar group. Within the above range, elastic properties, high dielectric constant and high breakdown strength properties can be taken into account at the same time.

[0023] Optionally, the reaction temperature of the chemical modification reaction is 15-70° C., and the reaction time is 0.5-24 h.

[0024] Those skilled in the art can set and adjust this according to the situation. For example, when the temperature is higher, the reaction is faster, so the reaction time can be controlled to be shorter, and vice versa.

[0025] Optionally, the reaction temperature of the chemical modification reaction is 30-60° C., and the reaction time is 1-8 hours.

[0026] The reaction rate under the above conditions is easy to control and the production efficiency is also higher.

[0027] Optionally, stirring is performed during the chemical modification reaction, and the stirring speed is 50-1000 rpm.

[0028] It should be noted that those skilled in the art can make selections and adjustments according to the circumstances. For example, by adding stirring operations, the reaction time can be shortened.

[0029] Optionally, the stirring speed is 200~700rpm.

[0030] Optionally, the organic solvent is one or more of toluene, dichloromethane, tetrahydrofuran, petroleum ether, and xylene.

[0031] It should be noted that, in addition to the organic solvents listed above, other solvents that can dissolve the reactants and provide a reaction environment can achieve the same effect, and those skilled in the art can select them as needed.

[0032] Optionally, the organic solvent is one or both of dichloromethane and tetrahydrofuran.

[0033] Optionally, the step of separating the polar butadiene-vinyl rubber from the butadiene-vinyl rubber solution after the reaction comprises the following steps: S1. Add a precipitant to precipitate the polar butadiene-pentadiene rubber; S2, deionized water cleaning; S3. After drying, polar butadiene-pentadiene rubber is obtained.

[0034] Optionally, the precipitant is one or more of methanol, ethanol, and acetone. It should be noted that, in addition to the precipitants listed above, those skilled in the art may also select other suitable precipitants.

[0035] Optionally, the vulcanizing agent used in the vulcanization of the polar butadiene-pentadiene rubber is one or more of sulfur, dibenzoyl peroxide, and diisopropylbenzene peroxide.

[0036] Optionally, the vulcanization accelerator used in the vulcanization of the polar butadiene-pentadiene rubber is one or more of CZ, NS, and TMTD.

[0037] Optionally, the mass ratio of polar butadiene-vinyl rubber, vulcanizing agent and vulcanization accelerator in the polar butadiene-vinyl rubber vulcanization is 100: (0.3~5): (0.3~5).

[0038] Optionally, the mass ratio of polar butadiene-vinyl rubber, vulcanizing agent and vulcanization accelerator in the polar butadiene-vinyl rubber vulcanization is 100:(0.5~3):(0.5~3).

[0039] During the vulcanization process, it is necessary to pay attention to controlling the amount of vulcanizing agent sulfur. If the amount of vulcanizing agent is too low, the mechanical properties will be poor; if the amount is too high, the tensile modulus will be high, requiring a higher driving voltage, which may cause breakdown. Therefore, it is necessary to control the amount of sulfur within an appropriate range.

[0040] Optionally, the polar butadiene-pentadiene rubber is vulcanized at a vulcanization temperature of 130-170° C. and a vulcanization time of 5-120 min.

[0041] Optionally, the polar butadiene-pentadiene rubber is vulcanized at a vulcanization temperature of 140-160° C. and a vulcanization time of 10-30 minutes.

[0042] The preparation of the new dielectric elastomer material in the present application is based on chemically modifying butadiene-pentadiene rubber to increase its polarity. The method is simple and fast to operate, has a high yield and a low overall production cost, and is very suitable for industrial production.

[0043] The present application provides a dielectric elastomer with a high dielectric constant, wherein the dielectric elastomer has the following structure:

[0044] And satisfy 0.2≤(a+d) / (a+b+c+d+e+f)≤0.6; R is one or more of -Cl, -SO3H, -Br, and -I.

[0045] It should be noted that the sum of the amounts of 1,2-butadiene and 3,4-isoprene in the butadiene-pentadiene rubber used accounts for more than 40% of the total amount of the four structural unit substances. The polar group partially modifies the side double bond, so the proportion of the modified side R group becomes smaller.

[0046] In addition, the above structural formula only reflects the structure modified by polar groups, and also contains side double bonds that are not modified by polar groups. Those skilled in the art can clearly understand the structure of the dielectric elastomer with a high dielectric constant in this application based on the above structural formula and reaction conditions and process.

[0047] The present application provides a dielectric elastomer prepared by the preparation method of the above-mentioned dielectric elastomer with a high dielectric constant or the application of the above-mentioned dielectric elastomer with a high dielectric constant in the fields of wearable electronics, flexible sensors, electronic skin, artificial muscles and soft robots.

[0048] The beneficial effects of this application include but are not limited to: 1. According to the dielectric elastomer with high dielectric constant and its preparation method and application of the present application, in view of the problems existing in dielectric elastomer rubber materials such as chloroprene rubber and nitrile rubber currently used in the prior art, a new dielectric elastomer material of butyl-butadiene rubber with high dielectric constant is provided, which not only has good rebound performance, but also has high dielectric constant due to the high dipole moment polar groups introduced into its branch chain by chemical modification, and its dielectric constant is increased by about 41% compared with polar nitrile rubber.

[0049] 2. According to the dielectric elastomer with high dielectric constant and its preparation method and application of the present application, based on the chemical modification of butyl-butadiene-vinyl rubber, a new dielectric elastomer material with excellent rebound performance, mechanical properties and electrical properties is obtained. Its excellent rebound performance, mechanical properties and high dielectric constant can achieve better rebound performance under a smaller driving voltage as a dielectric elastomer, making it a more ideal dielectric elastomer material compared to existing chloroprene rubber and nitrile rubber.

[0050] 3. According to the dielectric elastomer with high dielectric constant and its preparation method and application of the present application, the dielectric constant of the butadiene-vinyl rubber dielectric elastomer can be adjusted by adjusting the number of polar groups introduced, and the mechanical properties of the butadiene-vinyl rubber dielectric elastomer can be adjusted by adjusting the amount of vulcanizing agent added, thereby achieving control of the electrical and mechanical properties of the butadiene-vinyl rubber dielectric elastomer, thereby expanding the application field of the prepared butadiene-vinyl rubber dielectric elastomer, which is of great significance for its application in the fields of flexible actuators, soft robots, etc.

[0051] 4. According to the dielectric elastomer with high dielectric constant and its preparation method and application of the present application, the polarity of the butadiene-pentadiene rubber is changed by adding a halogenating agent in the chemical modification, not only the butadiene-pentadiene rubber with a higher dielectric constant is obtained, but also as the mass fraction of the halogenating agent, the reaction temperature and the reaction time increase (within a certain range), more polar functional groups such as chlorine atoms or ester groups with sulfur atoms are introduced into the butadiene-pentadiene rubber, so that the dielectric constant is higher. At the same time, since more polar groups are grafted on the side double bonds, the damage to the flexibility of the rubber main chain is avoided.

[0052] 5. According to the dielectric elastomer with high dielectric constant and its preparation method and application of the present application, by introducing polar functional groups: 1) the more polar functional groups introduced, the higher the dielectric constant of the elastomer; 2) however, the introduced polar functional groups will reduce the flexibility of the original molecular chain. When the flexibility of the rubber molecular chain is low, the resilience of the obtained modified rubber elastomer will deteriorate; 3) at the same time, introducing too many polar functional groups will reduce the breakdown strength of the rubber material, which is not suitable for use in high electric field environments. Within a reasonable range, elastic properties, high dielectric constant and high breakdown strength properties can be taken into account at the same time.

[0053] 6. According to the dielectric elastomer with high dielectric constant and its preparation method and application in this application, the preparation of the new dielectric elastomer material in this application is based on chemical modification of butadiene-vinyl rubber to improve its polarity. This method is simple and fast to operate, has high yield and low overall production cost, and is very suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 The reaction principle diagram of this application scheme; Figure 2 This is a diagram of the dielectric constant test results involved in this application. DETAILED DESCRIPTION

[0055] The present application is described in detail below in conjunction with examples, but the present application is not limited to these examples. Unless otherwise specified, the raw materials and reagents in the examples of the present application are purchased through commercial channels. For example, the nitrile rubber used in the comparative test is purchased from NBR 2850 Japan Zeon Co., Ltd. Unless otherwise specified, the butadiene-pentadiene rubber used in the present application is prepared by coordination polymerization using monomers butadiene and isoprene as raw materials using an iron-based catalyst.

[0056] In order to solve the problem that the current non-polar rubber has a low dielectric constant, which limits its application in dielectric elastomer actuators, the present application scheme chemically modifies the butadiene-pentadiene rubber matrix with a high double bond side group content, so that more polar groups are grafted onto the side groups of the molecular chain, thereby greatly improving the dielectric constant while reducing the impact on the flexibility of the molecular main chain, and preparing a dielectric elastomer rubber material with both high dielectric constant and high resilience. The reaction process is as follows: Figure 1 shown.

[0057] The present application scheme is described below through specific embodiments.

[0058] Example 1 (1) 50 g of raw butadiene-vinyl rubber (the sum of the amounts of 1,2-butadiene and 3,4-isoprene substances accounts for 62% of the total amount of the four structural unit substances, the sum of the amounts of cis-1,4-butadiene and cis-1,4-isoprene substances accounts for 73% of the total amount of 1,4-butadiene and 1,4-isoprene substances, the molecular weight of butadiene-vinyl rubber is 72w, and the molecular weight distribution is 2.1) is cut into small particles and fully dissolved in 1000 mL of tetrahydrofuran until the solution becomes uniform. The concentration of the butadiene-vinyl rubber solution is 5 g / 100 ml; (2) At 25°C, N-chlorosuccinimide was added to the N-butyl rubber solution, the weight ratio of the added N-chlorosuccinimide to the added N-butyl rubber was 1:6, and the mixture was stirred for 2 h at a stirring speed of 600 r / min; (3) adding methanol as a precipitant to precipitate the polar butadiene-pentadiene rubber, and then washing and drying the polar butadiene-pentadiene rubber for multiple times to obtain the polar butadiene-pentadiene rubber; (4) Add polar butyl rubber, vulcanizing agent and vulcanization accelerator into an internal mixer in a mass ratio of 100:2:0.8 and mix at 90°C for 4 minutes; (5) The uniformly mixed rubber material is placed in a mold and vulcanized at 150°C for 20 min to obtain a NBR dielectric elastomer.

[0059] Example 2 (1) 50 g of raw butadiene-vinyl rubber (the sum of the amounts of 1,2-butadiene and 3,4-isoprene accounts for 42% of the total amount of the four structural unit substances, the sum of the amounts of cis-1,4-butadiene and cis-1,4-isoprene accounts for 52% of the total amount of 1,4-butadiene and 1,4-isoprene substances, the molecular weight of butadiene-vinyl rubber is 77w, and the molecular weight distribution is 1.2) is cut into small particles and fully dissolved in 1000 mL of tetrahydrofuran until the solution becomes uniform. The concentration of the butadiene-vinyl rubber solution is 5 g / 100 ml; (2) Add sulfonyl chloride to the butyl terephthalate rubber solution at 15°C, with the weight ratio of the added sulfonyl chloride to the added butyl terephthalate rubber being 1:6, and react for 24 hours; (3) adding ethanol precipitant to precipitate polar butadiene-vinyl rubber, washing and drying the polar butadiene-vinyl rubber for multiple times to obtain the polar butadiene-vinyl rubber; (4) Add polar butyl rubber, vulcanizing agent and vulcanization accelerator into an internal mixer in a mass ratio of 100:2:0.8 and mix at 90°C for 4 minutes; (5) The uniformly mixed rubber material is placed in a mold and vulcanized at 150°C for 20 min to obtain a NBR dielectric elastomer.

[0060] Example 3 (1) 50 g of raw butadiene-vinyl rubber (the sum of the amounts of 1,2-butadiene and 3,4-isoprene substances accounts for 80% of the total amount of the four structural unit substances, the sum of the amounts of cis-1,4-butadiene and cis-1,4-isoprene substances accounts for 79% of the total amount of 1,4-butadiene and 1,4-isoprene substances, the molecular weight of butadiene-vinyl rubber is 64w, and the molecular weight distribution is 2.9) is cut into small particles and fully dissolved in 1000 mL of tetrahydrofuran until the solution becomes uniform. The concentration of the butadiene-vinyl rubber solution is 5 g / 100 ml; (2) At 70°C, trichloroisocyanuric acid was added to the butylene-vinyl rubber solution, the weight ratio of the added trichloroisocyanuric acid to the added butylene-vinyl rubber was 1:6, and stirring was continued for 0.5 h at a stirring speed of 200 r / min; (3) adding acetone as a precipitant to precipitate the polar butadiene-vinyl rubber, and then washing and drying the polar butadiene-vinyl rubber for multiple times to obtain the polar butadiene-vinyl rubber; (4) Add polar butyl rubber, vulcanizing agent and vulcanization accelerator into an internal mixer in a mass ratio of 100:2:0.8 and mix at 90°C for 4 minutes; (5) The uniformly mixed rubber material is placed in a mold and vulcanized at 150°C for 20 min to obtain a NBR dielectric elastomer.

[0061] Example 4 In this embodiment, the weight ratio of the added N-chlorosuccinimide to the added butadiene-vinyl rubber is 1:1, and the other conditions are the same as those in Example 1.

[0062] Example 5 In this embodiment, the weight ratio of the added N-chlorosuccinimide to the added butadiene-vinyl rubber is 1:15, and the other conditions are the same as those in Example 1.

[0063] Example 6 The sum of the amounts of 1,2-butadiene and 3,4-isoprene in the butylene-pentene rubber used in this example accounts for 41% of the total amount of the four structural unit substances, and the other conditions are the same as those in Example 1.

[0064] Example 7 The sum of the amounts of 1,2-butadiene and 3,4-isoprene in the butadiene-vinyl rubber used in this example accounts for 30% of the total amount of the four structural unit substances, and the other conditions are the same as those in Example 1.

[0065] Example 8 The molecular weight of the butadiene-vinyl rubber used in this embodiment is 30w, and the other conditions are the same as those in Example 1.

[0066] Example 9 The molecular weight distribution of the butadiene-vinyl rubber in the butadiene-vinyl rubber used in this embodiment is 4.3, and the other conditions are the same as those in Example 1.

[0067] Comparative Example 1 The difference between Comparative Example 1 and Example 1 is that the butadiene-vinyl rubber is replaced by styrene-butadiene rubber, and the other conditions are the same as those of Example 1.

[0068] Comparative Example 2 The nitrile rubber purchased for testing its mechanical properties, dielectric constant and breakdown voltage was NBR 2850 from Japan Zeon Co., Ltd.

[0069] Test Method The dielectric elastomers obtained in the examples and comparative examples were subjected to the following performance tests.

[0070] Mechanical property measurement: According to the national standard GB / T 589-2008, the dielectric elastomer sample is a 100 mm × 4 mm × 1 mm specimen.

[0071] Dielectric constant determination: The dielectric properties are tested at room temperature using an impedance meter with a test frequency of 100~10 6 The dielectric elastomer sample is a disc with a diameter of 2 cm and a thickness of 1 mm.

[0072] Breakdown strength measurement: Copper metal electrodes are deposited on the upper and lower surfaces of the dielectric elastomer material. Then the positive and negative electrodes of a DC high-voltage power supply are placed on the metal electrodes on the upper and lower surfaces and a voltage is applied to the material to obtain the breakdown strength.

[0073] The test results are shown in Table 1 below, where the dielectric constant test results are as follows: Figure 2 shown.

[0074] Table 1 Test results of dielectric elastomer properties of examples and comparative examples

[0075] According to the results in Table 1, compared with Examples 1 to 3: Example 4 increases the amount of halogenated reagent, resulting in a significant increase in the dielectric constant, but a significant decrease in the breakdown strength; Example 5 reduces the amount of halogenated reagent, the dielectric constant increases slightly, but the breakdown strength remains at a high level; the double bond side group content of the butadiene-pentadiene rubber used in Example 6 is low, so the dielectric constant increases relatively little, because part of the main chain double bonds react with the halogenated reagent, so the initial modulus increases, and the breakdown strength also decreases; the double bond side group content of the butadiene-pentadiene rubber used in Example 7 is further reduced, resulting in the main chain double bonds being reacted with the halogenated reagent, so the dielectric constant and The breakdown strength decreased, and the tensile properties were also affected; Example 8 used butadiene-vinyl rubber with a lower molecular weight, which resulted in a decrease in the mechanical properties of the material; Example 9 used butadiene-vinyl rubber with a higher molecular weight distribution, and the mechanical properties of the material also decreased; Comparative Example 1 used styrene-butadiene rubber for modification. Due to the low content of side double bonds and the large steric hindrance of the benzene ring, the dielectric constant of the modified styrene-butadiene rubber was low and the initial modulus was high, making it unsuitable for use as a dielectric elastomer material; Comparative Example 2 tested commercial nitrile rubber. Although the dielectric constant was high, the breakdown strength was too low, and it was also unsuitable for direct use as a dielectric elastomer material.

[0076] The above is only the embodiment of the present application, and the protection scope of the present application is not limited by these specific embodiments, but is determined by the claims of the present application. For those skilled in the art, the present application can have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the technical ideas and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a dielectric elastomer with a high dielectric constant, characterized in that: The preparation method comprises the following steps: 1) dissolving butadiene-vinyl rubber in an organic solvent to obtain butadiene-vinyl rubber solution; 2) Adding a halogenating agent to the butyl-pentene rubber solution to carry out a chemical modification reaction; 3) Separating polar butadiene-vinyl rubber from the butadiene-vinyl rubber solution after the reaction; 4) The polar butadiene-pentadiene rubber is vulcanized to obtain the dielectric elastomer with a high dielectric constant.

2. The method for preparing a dielectric elastomer with a high dielectric constant according to claim 1, characterized in that: The butadiene-vinyl rubber comprises four structural units, namely, 1,2-butadiene, 1,4-butadiene, 3,4-isoprene and 1,4-isoprene; the sum of the amounts of the 1,2-butadiene and 3,4-isoprene substances accounts for more than 40% of the total amount of the four structural unit substances.

3. The method for preparing a dielectric elastomer with a high dielectric constant according to claim 2, characterized in that: The 1,4-butadiene includes cis-1,4-butadiene and trans-1,4-butadiene, and the 1,4-isoprene includes cis-1,4-isoprene and trans-1,4-isoprene; The sum of the amounts of the cis-1,4-butadiene and cis-1,4-isoprene substances accounts for 50-80% of the total amount of the 1,4-butadiene and 1,4-isoprene substances.

4. The method for preparing a dielectric elastomer with a high dielectric constant according to claim 1, characterized in that: The molecular weight of the butadiene-pentadiene rubber is 50-100w.

5. The method for preparing a dielectric elastomer with a high dielectric constant according to claim 4, characterized in that: The molecular weight distribution of the butadiene-pentadiene rubber is 1.0-3.

0.

6. The method for preparing a dielectric elastomer with a high dielectric constant according to claim 1, characterized in that: The halogenating agent is one or more of N-chlorosuccinimide, sulfonyl chloride, trichloroisocyanuric acid and chlorinated imidazole ionic liquid.

7. The method for preparing a dielectric elastomer with a high dielectric constant according to claim 1, characterized in that: The mass ratio of the halogenating agent to the butadiene-pentadiene rubber is (10-50):

100.

8. The method for preparing a dielectric elastomer with a high dielectric constant according to claim 1, characterized in that: The reaction temperature of the chemical modification reaction is 15-70° C., and the reaction time is 0.5-24 h.

9. A dielectric elastomer having a high dielectric constant, characterized in that: The dielectric elastomer has the following structure: And satisfy 0.2≤(a+d) / (a+b+c+d+e+f)≤0.6; R is one or more of -Cl, -SO3H, -Br, and -I.

10. Application of the dielectric elastomer prepared by the method for preparing a dielectric elastomer with a high dielectric constant as described in any one of claims 1 to 8 or the dielectric elastomer with a high dielectric constant as described in claim 9 in the fields of wearable electronics, flexible sensors, electronic skin, artificial muscles and soft robots.

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