Silicone rubber dielectric elastomer material and preparation method thereof

Abstract

The invention discloses a silicone rubber dielectric elastomer material and a preparation method thereof. The silicone rubber dielectric elastomer material is prepared from the following raw materials in parts by weight: 100 parts of liquid silicone rubber base rubber, 30 to 150 parts of dimethyl silicone oil, 1 to 10 parts of hydrogen-containing silicone oil, 10 to 50 parts of modified BaTiO3, 0.02 to 0.1 part of an inhibitor and 0.5 to 1 part of a platinum catalyst. The modified BaTiO3 is prepared from nano BaTiO3, first vinyl-terminated polydimethylsiloxane and first white carbon black in the presence of an organic amine catalyst, and the first white carbon black is fumed silica with the specific surface area of 300g / cm < 2 >-400g / cm < 2 >. The silicone rubber dielectric elastomer material provided by the invention can effectively improve the compatibility of the dielectric material nano BaTiO3 and a silicone rubber system, can effectively improve the dielectric property, and has low elastic modulus.

Description

Technical Field

[0001] The present invention relates to the technical field of silicone rubber preparation, and in particular to a silicone rubber dielectric elastomer material and a preparation method thereof. Background Art

[0002] Silicone rubber is one of the important coating materials for intelligent robots. Currently, it mainly focuses on simple touch and appearance simulation, and has not yet involved functional simulation, such as the compression, expansion or twisting of biological muscles.

[0003] Silicone rubber is modified to create dielectric elastomers. By applying an electric field, electric-field-driven artificial muscles are fabricated, closely resembling the actuation of biological muscles. The electric field is established at the speed of light, does not decay with distance, and allows for independent control of the actuator units. Dielectric elastomer actuators are a typical example of electric-field-driven artificial muscles, with overall actuation performance most similar to that of biological muscles. Silicone rubber-based dielectric elastomers can achieve muscle contraction and displacement, further approaching realistic robotics in terms of facial micro-expressions and muscle tactile sensation.

[0004] Due to its inherently low chemical polarity, silicone rubber has a dielectric constant of only 2-3, which is relatively low among organic polymer materials. Modification is required to function as a dielectric elastomer. There are two main approaches: chemical modification and filler blending. The chemical modification method primarily focuses on constructing an elastomer network with highly polar groups. Highly polar groups have a larger dipole moment, contributing more to orientational polarization during dielectric polarization. However, the introduction of polar groups enhances the interactions between molecular chains, which inevitably raises the elastomer's glass transition temperature and elastic modulus, thereby losing the softness and low elastic modulus characteristic of silicone rubber. The filler blending method primarily involves adding high-dielectric-constant fillers, such as TiO2, BaTiO3, carbon black, carbon nanotubes, and graphene, to the elastomer matrix. When manufacturing these composite elastomers, it is crucial to prevent particle agglomeration within the matrix. Surface modification of the particles is often employed to achieve good particle dispersion. Zhang et al. (J. Mater. Chem. A, 2013, 1, 12276) modified BaTiO3 with dopamine to achieve compatibility with the matrix material; Tang et al. (China Plastics, Vol. 39, No. 1, 25-30) used a three-roll milling method to enhance material dispersion. However, these material processing methods are difficult to achieve for large-scale production due to cost, environmental concerns, and throughput.

[0005] Therefore, there is an urgent need for a silicone rubber dielectric elastomer material and a preparation method thereof to address the deficiencies in the prior art. Summary of the Invention

[0006] During the research and development process, the applicant discovered that by adding a large amount of inactive dimethyl silicone oil, the elastic modulus of silicone rubber can be reduced, and the viscosity of the silicone rubber system can be kept at a low level. However, at a low viscosity, the sedimentation of the dielectric material nano-BaTiO3 is aggravated, resulting in product uniformity differences, which has a negative impact on macroscopic dielectric properties. In view of the problems discovered during the aforementioned research and development process, the purpose of the present invention is to provide a silicone rubber dielectric elastomer material and a preparation method thereof. This silicone rubber dielectric elastomer material can effectively improve the compatibility of the dielectric material nano-BaTiO3 with the silicone rubber system, effectively improve the dielectric properties, and at the same time have a low elastic modulus.

[0007] To achieve the above-mentioned object, the present invention provides a silicone rubber dielectric elastomer material. The raw materials for preparation include, by weight, 100 parts of liquid silicone rubber base, 30 to 150 parts of dimethyl silicone oil, 1 to 10 parts of hydrogenated silicone oil, 10 to 50 parts of modified BaTiO3, 0.02 to 0.1 parts of inhibitor, and 0.5 to 1 parts of platinum catalyst. The modified BaTiO3 is prepared by nano-BaTiO3, a first vinyl-terminated polydimethylsiloxane, and a first white carbon black under the conditions of an organic amine catalyst. The first white carbon black has a specific surface area of ​​300 g / cm 2 ~400 g / cm 2 of fumed silica.

[0008] Compared with the existing technology, the present invention uses vinyl-terminated polydimethylsiloxane and white carbon black to modify nano BaTiO3 under the condition of organic amine catalyst. Among them, the surface of nano BaTiO3 contains a large number of Ti-OH groups. Under the condition of organic amine catalyst, the Ti-OH groups can react with the siloxane segments to form Ti-O-Si bonds, thereby grafting the polysiloxane segments to the surface of nano BaTiO3. At the same time, the white carbon black has a specific surface area of ​​300g / cm 2 ~400 g / cm 2 The modified BaTiO of the present invention can enhance the shear force of the reaction system and maintain the dispersion of the system, thereby further fully dispersing the nano BaTiO. The modified BaTiO of the present invention can improve its compatibility with the silicone rubber system due to containing siloxane segments and vinyl functional groups at the same time. The vinyl functional groups contained at the same time can react with hydrogenated silicone oil to produce a silylation reaction, so that the modified BaTiO can be further connected to the silicone rubber system through a chemical bond, effectively avoiding the situation of nano BaTiO sedimentation due to weak bonding force and / or containing a high weight fraction of dimethyl silicone oil in the silicone rubber system. Therefore, the silicone rubber dielectric elastomer material of the present invention can effectively improve the compatibility of dielectric material nano BaTiO with the silicone rubber system, ensuring that it has a lower elastic modulus while improving dielectric properties.

[0009] Furthermore, the weight ratio of the first vinyl-terminated polydimethylsiloxane, the first white carbon black, the modified BaTiO3, and the organic amine catalyst of the present invention is 100:30:30~80:0.01~0.1.

[0010] Furthermore, the viscosity of the first vinyl-terminated polydimethylsiloxane of the present invention is 500 mPa·s to 2000 mPa·s. Furthermore, the organic amine catalyst of the present invention is at least one selected from 4-dimethylaminopyridine, 1,8-diazabicycloundec-7-ene, and 1,5-diazabicyclonon-5-ene.

[0011] Furthermore, the raw materials for preparing the liquid silicone rubber base of the present invention include 100 parts by weight of a second vinyl-terminated polydimethylsiloxane, 30 to 90 parts by weight of a second white carbon black, 6 to 20 parts by weight of hexamethyldisilazane, and 1 to 2 parts by weight of water.

[0012] Furthermore, the viscosity of the second vinyl-terminated polydimethylsiloxane of the present invention is 500 mPa·s to 10000 mPa·s.

[0013] Furthermore, the specific surface area of ​​the second white carbon black of the present invention is 150 g / cm 2 ~400g / cm 2 The second silica is at least one of fumed silica and precipitated silica.

[0014] Furthermore, the hydrogen-containing silicone oil of the present invention is a hydrogen-containing silicone oil in which active hydrogen is located at both ends and side chains and the mass content of active hydrogen is 0.1% to 0.2%, and the viscosity is 10 mPa·s to 50 mPa·s, and / or the hydrogen-containing silicone oil is a hydrogen-containing silicone oil in which active hydrogen is located at the side chains and the mass content of active hydrogen is 0.1% to 0.4%, and the viscosity is 30 mPa·s to 100 mPa·s.

[0015] Furthermore, the viscosity of the dimethyl silicone oil of the present invention is 10 cs to 500 cs.

[0016] Furthermore, the inhibitor of the present invention is selected from at least one of ethynylcyclohexanol, methylbutynol and tetramethyltetravinylcyclotetrasiloxane.

[0017] Furthermore, the platinum catalyst of the present invention is a Custer catalyst or a Speier catalyst, and the platinum content is 3000-5000 ppm.

[0018] Another aspect of the present invention provides a method for preparing the aforementioned silicone rubber dielectric elastomer material, comprising adding a formulated amount of liquid silicone rubber base, dimethyl silicone oil, hydrogenated silicone oil, modified BaTiO3, and an inhibitor into a planetary mixer, stirring evenly, and then adding a platinum catalyst for vulcanization.

[0019] Furthermore, the preparation of the modified BaTiO3 of the present invention includes placing the formulated amount of the first vinyl-terminated polydimethylsiloxane, the first white carbon black, nano-BaTiO3 and the organic amine catalyst in an internal mixer and mixing them evenly, then internally mixing at 160°C~195°C for 8h~25h, and then maintaining the internal mixing at 160°C~195°C under vacuum conditions for 2h~5h.

[0020] Furthermore, the preparation of the liquid silicone rubber base of the present invention includes placing the formulated amount of the second vinyl-terminated polydimethylsiloxane, the second white carbon black, hexamethyldisilazane and water in an internal mixer and mixing them for 1 to 2 hours, then heating the temperature to 150° C. to 180° C. and vacuum mixing them for 3 to 6 hours. DETAILED DESCRIPTION

[0021] The silicone rubber dielectric elastomer material of the present invention is prepared from raw materials, calculated by weight, including 100 parts of liquid silicone rubber base, 30 to 150 parts of dimethyl silicone oil, 1 to 10 parts of hydrogenated silicone oil, 10 to 50 parts of modified BaTiO3, 0.02 to 0.1 parts of inhibitor and 0.5 to 1 parts of platinum catalyst.

[0022] Wherein, the weight parts of dimethyl silicone oil can be but not limited to 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, 90 parts, 100 parts, 110 parts, 120 parts, 130 parts, 140 parts, 150 parts. The viscosity of dimethyl silicone oil is 10cs to 500cs. As an example, the viscosity of dimethyl silicone oil can be but not limited to 10cs, 20cs, 50cs, 100cs, 150cs, 200cs, 250cs, 300cs, 350cs, 400cs, 450cs, 500cs. Using dimethyl silicone oil with a viscosity of 10cs to 500cs and controlling its weight parts to 30 parts to 150 parts can effectively reduce the elastic modulus of the silicone rubber system of the present invention.

[0023] The weight proportions of hydrogen-containing silicone oil may be, but are not limited to, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts. The hydrogen-containing silicone oil may be a hydrogen-containing silicone oil in which active hydrogen is located at both ends and in the side chains, and the mass content of active hydrogen is 0.1 to 0.2%, and the viscosity is 10 mPa·s to 50 mPa·s. For example, the mass content of active hydrogen may be, but are not limited to, 0.1%, 0.12%, 0.14%, 0.15%, 0.16%, 0.18%, or 0.2%, and the viscosity may be, but are not limited to, 10 mPa·s, 15 mPa·s, 20 mPa·s, 25 mPa·s, 30 mPa·s, 35 mPa·s, 40 mPa·s, 45 mPa·s, or 50 mPa·s. Hydrogen-containing silicone oil can be the hydrogen-containing silicone oil that active hydrogen is positioned at side chain and the mass content of active hydrogen is 0.1~0.4%, and viscosity is 30mPa·s~100mPa·s, as an example, the mass content of active hydrogen can be but not limited to 0.1%, 0.12%, 0.14%, 0.16%, 0.18%, 0.2%, 0.22%, 0.24%, 0.26%, 0.28%, 0.3%, 0.35%, 0.4%, and viscosity can be but not limited to 30mPa·s, 40mPa·s, 50mPa·s, 60mPa·s, 70mPa·s, 80mPa·s, 90mPa·s, 100mPa·s. Hydrogen-containing silicone oil can also be the mixing of aforementioned two kinds of hydrogen-containing silicone oils. The mass content of hydrogen-containing silicone oil is controlled within the above range, the cross-linking density of silicone rubber in vulcanization process can be effectively reduced, thereby further reducing the elastic modulus of silicone rubber dielectric elastomer of the present invention.

[0024] The weight percentage of the inhibitor can be, but is not limited to, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, or 0.1. The inhibitor can be selected from at least one of ethynylcyclohexanol, methylbutynol, and tetramethyltetravinylcyclotetrasiloxane.

[0025] The weight percentage of the platinum catalyst can be, but is not limited to, 0.5, 0.6, 0.7, 0.8, 0.9, or 1. The platinum catalyst is a Custer catalyst or a Speier catalyst, and the platinum content is 3000 ppm to 5000 ppm. For example, the platinum content can be, but is not limited to, 3000 ppm, 3500 ppm, 4000 ppm, 4500 ppm, or 5000 ppm.

[0026] The raw materials for preparing the liquid silicone rubber base include 100 parts by weight of a second vinyl-terminated polydimethylsiloxane, 30-90 parts by weight of a second silica, 6-20 parts by weight of hexamethyldisilazane, and 1-2 parts by weight of water. The second vinyl-terminated polydimethylsiloxane refers to an organosilicon polymer with vinyl groups at both ends of the molecular chain and a middle segment composed of repeating dimethylsiloxane segments. The second vinyl-terminated polydimethylsiloxane of the present invention can be prepared by conventional methods in the art or obtained from a common commercial source. The viscosity of the second vinyl-terminated polydimethylsiloxane is 500 mPa·s to 10,000 mPa·s, and the mass fraction of the vinyl group is 0.13% to 0.43%. For example, the viscosity of the second vinyl-terminated polydimethylsiloxane can be, but is not limited to, 500 mPa·s, 1,000 mPa·s, 2,000 mPa·s, 5,000 mPa·s, 8,000 mPa·s, and 10,000 mPa·s, and the mass fraction of the vinyl group can be, but is not limited to, 0.13%, 0.14%, 0.15%, 0.16%, 0.17%, 0.18%, 0.20%, 0.21%, 0.25%, 0.28%, 0.30%, 0.31%, 0.35%, 0.38%, and 0.43%. The weight percentage of the second silica can be, but is not limited to, 30 parts, 40 parts, 50 parts, 60 parts, 70 parts, 80 parts, or 90 parts. The specific surface area of ​​the second silica is 150 g / cm 2 ~400g / cm 2 As an example, it can be but not limited to 150g / cm 2 , 200g / cm 2 , 250g / cm 2 , 300g / cm 2 、350g / cm 2 , 400g / cm 2 The second silica may be at least one of fumed silica and precipitated silica. For example, the second silica has a specific surface area of ​​166 g / cm 2 The second silica may also be a precipitated silica with a specific surface area of ​​200 g / cm 2 The weight percentage of hexamethyldisilazane can be, but is not limited to, 6 parts, 8 parts, 10 parts, 12 parts, 14 parts, 16 parts, 18 parts, or 20 parts. The weight percentage of water can be, but is not limited to, 1 part, 1.1 parts, 1.2 parts, 1.3 parts, 1.4 parts, 1.5 parts, 1.6 parts, 1.7 parts, 1.8 parts, 1.9 parts, or 2 parts.

[0027] Modified BaTiO3 is prepared from nano-BaTiO3, a first vinyl-terminated polydimethylsiloxane, and a first white carbon black under the condition of an organic amine catalyst. Specifically, the weight ratio of the first vinyl-terminated polydimethylsiloxane, the first white carbon black, the modified BaTiO3, and the organic amine catalyst is 100:30:30~80:0.01~0.1. As an example, the weight ratio of the first vinyl-terminated polydimethylsiloxane, the first white carbon black, the modified BaTiO3, and the organic amine catalyst can be, but is not limited to, 100:30:30:0.01, 100:30:40:0.01, 100:30:50:0.01, 100:30:60:0.01, 100:30:70:0.01, 100:30:80:0.01, 100:30:30:0.05, 1 00:30:40:0.05, 100:30:50:0.05, 100:30:60:0.05, 100:30:70:0.05, 100:30:80:0.05, 100:30:30:0.1, 100:30:40:0.1, 100:30:50:0.1, 100:30:60:0.1, 100:30:70:0.1, 100:30:80:0.1. The first vinyl-terminated polydimethylsiloxane refers to an organosilicon polymer having vinyl groups at both ends of the molecular chain and a middle segment composed of repeated dimethylsiloxane segments. The first vinyl-terminated polydimethylsiloxane of the present invention can be prepared by conventional preparation methods in the art or obtained from ordinary commercial products. The viscosity of the first vinyl-terminated polydimethylsiloxane is 500mPa·s~2000mPa·s, and the mass fraction of the vinyl group is 0.21%~0.43%. As an example, the viscosity of the first vinyl-terminated polydimethylsiloxane can be, but is not limited to, 500mPa·s, 800mPa·s, 1000mPa·s, 1200mPa·s, 1400mPa·s, 1500mPa·s, 1600mPa·s, 1800mPa·s, and 2000mPa·s, and the mass fraction of the vinyl group can be, but is not limited to, 0.21%, 0.25%, 0.28%, 0.30%, 0.31%, 0.32%, 0.33%, 0.35%, 0.36%, 0.38%, 0.40%, 0.41%, and 0.43%. The first silica is fumed silica, and the specific surface area of ​​the first silica is 300g / cm 2 ~400g / cm 2 As an example, the specific surface area of ​​the first silica can be, but is not limited to, 300 or 310 g / cm 2 、320g / cm 2 、330g / cm 2 、340g / cm 2 、350g / cm 2、360g / cm 2 、370g / cm 2 、380g / cm 2 、390g / cm 2 , 400g / cm 2 The organic amine catalyst is selected from at least one of 4-dimethylaminopyridine, 1,8-diazabicycloundec-7-ene, and 1,5-diazabicyclonon-5-ene.

[0028] The preparation method of the silicone rubber dielectric elastomer material of the present invention comprises adding a formulated amount of liquid silicone rubber base, dimethyl silicone oil, hydrogenated silicone oil, modified BaTiO3, and an inhibitor to a planetary mixer, stirring evenly, and then adding a platinum catalyst for vulcanization. The vulcanization temperature is 100°C to 170°C. As an example, the vulcanization temperature can be, but is not limited to, 100°C, 110°C, 120°C, 130°C, 140°C, 150°C, 160°C, or 170°C. The vulcanization time is 20 minutes to 30 minutes. As an example, the vulcanization time can be, but is not limited to, 20 minutes, 21 minutes, 22 minutes, 23 minutes, 24 minutes, 25 minutes, 26 minutes, 27 minutes, 28 minutes, 29 minutes, or 30 minutes.

[0029] The preparation of modified BaTiO3 includes placing a formulated amount of a first vinyl-terminated polydimethylsiloxane, a first white carbon black, nano-BaTiO3, and an organic amine catalyst in an internal mixer and mixing them uniformly, then internally kneading at 160°C to 195°C for 8h to 25h, and then maintaining the internal kneading at 160°C to 195°C under vacuum conditions for 2h to 5h. Specifically, the internal kneading is performed at 160°C to 195°C for 8h to 25h. As an example, the temperature can be, but is not limited to, 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, and 195°C, and the time can be, but is not limited to, 8h, 9h, 10h, 11h, 12h, 13h, 14h, 15h, 16h, 17h, 18h, 19h, 20h, 22h, 24h, and 25h. Specifically, the kneading is maintained at 160°C~195°C under vacuum conditions for 2h~5h, and the vacuum degree is 0.06MPa~0.098MPa. As an example, the vacuum degree can be but not limited to 0.06MPa, 0.07MPa, 0.08MPa, 0.09MPa, 0.092MPa, 0.094MPa, 0.096MPa, 0.098MPa, the temperature can be but not limited to 160°C, 165°C, 170°C, 175°C, 180°C, 185°C, 190°C, 195°C, and the time can be but not limited to 2h, 3h, 4h, 5h.

[0030] The preparation of the liquid silicone rubber base comprises mixing the formulated amounts of the second vinyl-terminated polydimethylsiloxane, the second silica, hexamethyldisilazane, and water in an internal mixer for 1-2 hours, then heating the mixture to 150-180°C and performing vacuum mixing for 3-6 hours. For example, the vacuum mixing temperature may be, but is not limited to, 150°C, 155°C, 160°C, 165°C, 170°C, 175°C, or 180°C, and the vacuum mixing time may be, but is not limited to, 3 hours, 4 hours, 5 hours, or 6 hours.

[0031] In order to better illustrate the purpose, technical solutions and beneficial effects of the present invention, the present invention will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of the present invention and should not be used as a limitation of the present invention.

[0032] The nano-BaTiO3 in the examples and comparative examples was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., and the other raw materials not described here were obtained from common commercial sources.

[0033] Example 1 This embodiment provides a silicone rubber dielectric elastomer material. The raw materials for preparation include, by weight, 100 parts of liquid silicone rubber base type I, 50 parts of dimethyl silicone oil (viscosity of 50 cs), 9 parts of hydrogenated silicone oil (active hydrogen content of 0.15% by mass, active hydrogen located at both ends and side chains, with a molar ratio of active hydrogen at both ends to active hydrogen in the side chains of 2:1, and a viscosity of 25 mPa·s), 50 parts of modified BaTiO3 type I, 0.02 parts of ethynyl cyclohexanol, and 0.5 parts of a Custer catalyst with a platinum content of 3000 ppm. The modified BaTiO3 type I is composed of a first vinyl-terminated polydimethylsiloxane (viscosity of 2000 mPa·s, vinyl content of 0.21%), a first silica (specific surface area of ​​400 g / cm 2 The first vinyl-terminated polydimethylsiloxane, the first silica, the nano-BaTiO3 and the 4-dimethylaminopyridine are prepared in a weight ratio of 100:30:30:0.05.

[0034] The raw materials for the preparation of liquid silicone rubber base type I include 100 parts of a second vinyl-terminated polydimethylsiloxane (viscosity of 2000 mPa·s, vinyl content of 0.21%), 40 parts of a second white carbon black (specific surface area of ​​200 g / cm 2 of fumed silica), 10 parts of hexamethyldisilazane and 1.2 parts of water.

[0035] The present embodiment also provides a preparation method of the above-mentioned silicone rubber dielectric elastomer material, which comprises adding the aforementioned liquid silicone rubber base glue I type, dimethyl silicone oil, hydrogen-containing silicone oil, modified BaTiO3 I type, and ethynylcyclohexanol in a planetary mixer, discharging after stirring for 1 h, and then adding 0.5 parts of a platinum-containing Kast catalyst with a platinum content of 3000 ppm for vulcanization, wherein the vulcanization temperature is 120°C, and the vulcanization time is 25 min.

[0036] The preparation of the modified BaTiO3 I type comprises adding 100 parts by weight of a vinyl-terminated polydimethylsiloxane (viscosity: 2000 mPa·s, vinyl content: 0.21%) into a mixer, keeping the rotation speed at 50 Hz, adding 30 parts by weight of a first white carbon black (specific surface area: 400 g / cm 2 of a fumed white carbon black), mixing uniformly after mixing, adding 30 parts by weight of nano BaTiO3, mixing uniformly, adding 0.05 parts by weight of 4-dimethylaminopyridine, starting heating, keeping the mixer at 195°C for 8 h, then starting vacuum and keeping the mixer at 195°C for 2 h, and obtaining the modified BaTiO3 after cooling.

[0037] The preparation of the liquid silicone rubber base glue I type comprises placing 100 parts by weight of a vinyl-terminated polydimethylsiloxane (viscosity: 2000 mPa·s, vinyl content: 0.21%), 40 parts by weight of a second white carbon black (specific surface area: 200 g / cm 2 of a fumed white carbon black), 10 parts by weight of hexamethyldisilazane, and 1.2 parts by weight of water into a mixer, mixing for 2 h, and then vacuum mixing at 180°C for 3 h to obtain the liquid silicone rubber base glue I type.

[0038] Example 2 The present embodiment provides a silicone rubber dielectric elastomer material, and the preparation raw materials include, in parts by weight, 100 parts of a liquid silicone rubber base glue II type, 50 parts of dimethyl silicone oil (viscosity: 50 cs), 9 parts of hydrogen-containing silicone oil (mass content of active hydrogen: 0.15%, active hydrogen located at both ends and side chains, molar ratio of active hydrogen at both ends to that at side chains: 2:1, viscosity: 25 mPa·s), 50 parts of modified BaTiO3 I type, 0.02 parts of ethynylcyclohexanol, and 0.5 parts of a Kast catalyst with a platinum content of 3000 ppm. The preparation raw materials of the modified BaTiO3 I type are the same as those in Example 1.

[0039] The preparation raw materials of the liquid silicone rubber base glue II type include 100 parts of a second vinyl-terminated polydimethylsiloxane (viscosity: 2000 mPa·s, vinyl content: 0.21%), 40 parts of a second white carbon black (specific surface area: 166 g / cm 2 of a precipitated white carbon black), 10 parts of hexamethyldisilazane, and 1.2 parts of water.

[0040] This embodiment also provides a method for preparing the above-mentioned silicone rubber dielectric elastomer material, comprising adding the aforementioned parts by weight of liquid silicone rubber base type II, dimethyl silicone oil, hydrogenated silicone oil, modified BaTiO3 type I, and ethynyl cyclohexanol into a planetary mixer, stirring for 1 hour and then unloading, and then adding 0.5 parts of a Custer catalyst with a platinum content of 3000 ppm for vulcanization, the vulcanization temperature being 120° C. and the vulcanization time being 25 minutes.

[0041] The preparation of modified BaTiO3I type is the same as that in Example 1.

[0042] Liquid silicone rubber base type II was prepared by mixing 100 parts by weight of vinyl-terminated polydimethylsiloxane (viscosity 2000 mPa·s, vinyl content 0.21%), 40 parts by weight of second silica (specific surface area 166 g / cm 2 precipitated silica), 10 parts by weight of hexamethyldisilazane and 1.2 parts by weight of water were placed in an internal mixer and mixed for 2 hours, then heated to 180° C. and vacuum mixed for 3 hours to obtain liquid silicone rubber base type II.

[0043] Example 3 This embodiment provides a silicone rubber dielectric elastomer material. The raw materials for preparation include, by weight, 100 parts of liquid silicone rubber base type I, 50 parts of dimethyl silicone oil (viscosity of 50 cs), 8.5 parts of hydrogen-containing silicone oil (active hydrogen content of 0.15% by mass, active hydrogen located at both ends and side chains, the molar ratio of active hydrogen at both ends to active hydrogen in the side chains is 2:1, and the viscosity is 25 mPa·s), 50 parts of modified BaTiO3 type II, 0.02 parts of ethynyl cyclohexanol, and 0.5 parts of a Custer catalyst with a platinum content of 3000 ppm. The modified BaTiO3 type II is composed of a first vinyl-terminated polydimethylsiloxane (viscosity of 2000 mPa·s, vinyl content of 0.21%), a first white carbon black (specific surface area of ​​400 g / cm 2 The first vinyl-terminated polydimethylsiloxane, the first silica, the nano-BaTiO3 and the 4-dimethylaminopyridine are prepared in a weight ratio of 100:30:50:0.05.

[0044] The raw materials for preparing liquid silicone rubber base type I are the same as those in Example 1.

[0045] This embodiment also provides a method for preparing the above-mentioned silicone rubber dielectric elastomer material, comprising adding liquid silicone rubber base type I, dimethyl silicone oil, hydrogenated silicone oil, modified BaTiO3 type II, and ethynyl cyclohexanol into a planetary mixer, stirring for 1 hour and then unloading, and then adding 0.5 parts of a Custer catalyst with a platinum content of 3000 ppm for vulcanization, the vulcanization temperature being 120°C and the vulcanization time being 25 minutes.

[0046] The preparation of modified BaTiO3 type II includes adding 100 parts by weight of vinyl-terminated polydimethylsiloxane (viscosity of 2000 mPa·s, vinyl content of 0.21%) into an internal mixer, maintaining the speed at 50 Hz, adding 30 parts by weight of first white carbon black (specific surface area of ​​400 g / cm 2 After mixing, add 50 parts by weight of nano-BaTiO3 and mix evenly, then add 0.05 parts by weight of 4-dimethylaminopyridine, turn on the heating, keep it at 160℃ and knead for 25h, then turn on the vacuum and keep it at 195℃ and knead for 5h, and then cool to obtain modified BaTiO3.

[0047] The preparation of liquid silicone rubber base type I is the same as in Example 1.

[0048] Example 4 This example provides a silicone rubber dielectric elastomer material. The raw materials, in parts by weight, include 100 parts of liquid silicone rubber base type II, 50 parts of dimethyl silicone oil (viscosity 50 cs), 8.5 parts of hydrogenated silicone oil (active hydrogen content 0.15% by weight, with active hydrogen located at both ends and side chains, a molar ratio of active hydrogen at both ends to active hydrogen in the side chains of 2:1, and a viscosity of 25 mPa·s), 50 parts of modified BaTiO3 type II, 0.02 parts of ethynylcyclohexanol, and 0.5 parts of a Custer catalyst containing 3000 ppm of platinum. The raw materials used in preparing the modified BaTiO3 type II are the same as those in Example 3.

[0049] The raw materials for preparing liquid silicone rubber base type II are the same as those in Example 2.

[0050] This embodiment also provides a method for preparing the above-mentioned silicone rubber dielectric elastomer material, comprising adding liquid silicone rubber base type II, dimethyl silicone oil, hydrogenated silicone oil, modified BaTiO3 type II, and ethynyl cyclohexanol into a planetary mixer, stirring for 1 hour and then unloading, and then adding 0.5 parts of a Custer catalyst with a platinum content of 3000 ppm for vulcanization, the vulcanization temperature being 120° C. and the vulcanization time being 25 minutes.

[0051] The preparation of modified BaTiO3II type is the same as in Example 3 The preparation of liquid silicone rubber base type II is the same as in Example 2.

[0052] Example 5 This example provides a silicone rubber dielectric elastomer material. The raw materials, in parts by weight, include 100 parts of liquid silicone rubber base type II, 80 parts of dimethyl silicone oil (viscosity 50 cs), 6.8 parts of hydrogenated silicone oil (active hydrogen content 0.15% by weight, with active hydrogen located at both ends and side chains, a molar ratio of active hydrogen at both ends to active hydrogen in the side chains of 2:1, and a viscosity of 25 mPa·s), 10 parts of modified BaTiO3 type II, 0.02 parts of ethynylcyclohexanol, and 0.5 parts of a Custer catalyst containing 3000 ppm of platinum. The raw materials for preparing the modified BaTiO3 type II are the same as those in Example 3.

[0053] The raw materials for preparing liquid silicone rubber base type II are the same as those in Example 2.

[0054] This embodiment also provides a method for preparing the above-mentioned silicone rubber dielectric elastomer material, comprising adding liquid silicone rubber base type II, dimethyl silicone oil, hydrogenated silicone oil, modified BaTiO3 type II, and ethynyl cyclohexanol into a planetary mixer, stirring for 1 hour and then unloading, and then adding 0.5 parts of a Custer catalyst with a platinum content of 3000 ppm for vulcanization, the vulcanization temperature being 120° C. and the vulcanization time being 25 minutes.

[0055] The preparation of modified BaTiO3 type II is the same as in Example 3.

[0056] The preparation of liquid silicone rubber base type II is the same as in Example 2.

[0057] Example 6 This example provides a silicone rubber dielectric elastomer material. The raw materials for preparation, in parts by weight, include 100 parts of liquid silicone rubber base type III, 50 parts of dimethyl silicone oil (viscosity 50 cs), 4 parts of hydrogenated silicone oil (active hydrogen content 0.36% by weight, located in the side chains, viscosity 60 cs), 50 parts of modified BaTiO3 type II, 0.02 parts of ethynylcyclohexanol, and 0.5 parts of a Custer catalyst containing 3000 ppm of platinum. The raw materials for preparing the modified BaTiO3 type II are the same as those in Example 3.

[0058] The raw materials for the preparation of liquid silicone rubber base type III include 100 parts of a second vinyl-terminated polydimethylsiloxane (viscosity of 10,000 mPa·s, vinyl content of 0.13%), 40 parts of a second silica (specific surface area of ​​166 g / cm 2 of precipitated silica), 10 parts of hexamethyldisilazane and 1.2 parts of water.

[0059] This embodiment also provides a method for preparing the above-mentioned silicone rubber dielectric elastomer material, comprising adding liquid silicone rubber base type III, dimethyl silicone oil, hydrogenated silicone oil, modified BaTiO3 type II, and ethynyl cyclohexanol into a planetary mixer, stirring for 1 hour and then unloading, and then adding 0.5 parts of a Custer catalyst with a platinum content of 3000 ppm for vulcanization, the vulcanization temperature being 120°C and the vulcanization time being 25 minutes.

[0060] The preparation of modified BaTiO3 type II is the same as in Example 3.

[0061] Liquid silicone rubber base type III was prepared by mixing 100 parts by weight of vinyl-terminated polydimethylsiloxane (viscosity of 10,000 mPa·s, vinyl content of 0.13%), 40 parts by weight of a second silica (specific surface area of ​​166 g / cm 2 precipitated silica), 10 parts by weight of hexamethyldisilazane and 1.2 parts by weight of water were placed in an internal mixer and mixed for 2 hours, then heated to 180° C. and mixed in a vacuum mixer for 3 hours to obtain liquid silicone rubber base type I.

[0062] Comparative Example 1 This comparative example provides a silicone rubber dielectric elastomer material. The raw materials, measured in parts by weight, include 100 parts of liquid silicone rubber base type I, 50 parts of dimethyl silicone oil (viscosity 50 cs), 8.5 parts of hydrogenated silicone oil (active hydrogen content 0.15% by weight, with active hydrogen located at both ends and side chains, a molar ratio of active hydrogen at both ends to active hydrogen in side chains of 2:1, and a viscosity of 25 mPa·s), 50 parts of modified BaTiO3 type A, 0.02 parts of ethynylcyclohexanol, and 0.5 parts of a Custer catalyst containing 3000 ppm platinum. The modified BaTiO3 type A is prepared from a first vinyl-terminated polydimethylsiloxane (viscosity 2000 mPa·s, vinyl content 0.21%) and nano-BaTiO3 in the presence of 4-dimethylaminopyridine. The weight ratio of the first vinyl-terminated polydimethylsiloxane, nano-BaTiO3, and 4-dimethylaminopyridine is 100:50:0.05.

[0063] The raw materials for preparing liquid silicone rubber base type I are the same as those in Example 1.

[0064] This comparative example also provides a method for preparing the above-mentioned silicone rubber dielectric elastomer material, comprising adding liquid silicone rubber base type I, dimethyl silicone oil, hydrogenated silicone oil, modified BaTiO3 type A, and ethynyl cyclohexanol into a planetary mixer, stirring for 1 hour and then unloading the material, and then adding a Custer catalyst with a platinum content of 3000 ppm for vulcanization. The vulcanization temperature is 120°C and the vulcanization time is 25 minutes.

[0065] The preparation of modified BaTiO3 type A includes adding 100 parts by weight of vinyl-terminated polydimethylsiloxane (viscosity of 2000 mPa·s and vinyl content of 0.21%) to an internal mixer, maintaining the speed at 50 Hz, adding 50 parts by weight of nano-BaTiO3 and mixing uniformly, adding 0.05 parts by weight of 4-dimethylaminopyridine, turning on the heat, maintaining the internal mixing at 195°C for 8 hours, then turning on the vacuum and maintaining the internal mixing at 195°C for 2 hours, and obtaining the modified BaTiO3 after cooling.

[0066] The preparation of liquid silicone rubber base type I is the same as in Example 1.

[0067] Comparative Example 2 This comparative example provides a silicone rubber dielectric elastomer material, the raw materials for preparation of which include, by weight, 100 parts of liquid silicone rubber base type I, 50 parts of dimethyl silicone oil (viscosity of 50 cs), 8.5 parts of hydrogenated silicone oil (mass content of active hydrogen is 0.15%, active hydrogen is located at both ends and side chains, the molar ratio of active hydrogen at both ends to active hydrogen in the side chains is 2:1, and the viscosity is 25 mPa·s), 50 parts of modified BaTiO3 type B, 0.02 parts of ethynyl cyclohexanol, and 0.5 parts of a Custer catalyst with a platinum content of 3000 ppm. The modified BaTiO3 is composed of a first vinyl-terminated polydimethylsiloxane (viscosity of 2000 mPa·s, vinyl content of 0.21%), a first white carbon black (specific surface area of ​​200 g / cm 2 The first vinyl-terminated polydimethylsiloxane, the first silica, the nano-BaTiO3 and the 4-dimethylaminopyridine are prepared in a weight ratio of 100:30:50:0.05.

[0068] The raw materials for preparing liquid silicone rubber base type I are the same as those in Example 1.

[0069] This comparative example also provides a method for preparing the above-mentioned silicone rubber dielectric elastomer material, comprising adding liquid silicone rubber base type I, dimethyl silicone oil, hydrogenated silicone oil, modified BaTiO3 type B, and ethynyl cyclohexanol into a planetary mixer, stirring for 1 hour and then unloading the material, and then adding a Custer catalyst with a platinum content of 3000 ppm for vulcanization. The vulcanization temperature is 120°C and the vulcanization time is 25 minutes.

[0070] The preparation of modified BaTiO3B type includes adding 100 parts by weight of vinyl-terminated polydimethylsiloxane (viscosity of 2000 mPa·s, vinyl content of 0.21%) into an internal mixer, maintaining the speed at 50 Hz, adding 30 parts by weight of the first white carbon black (specific surface area of ​​200 g / cm 2After mixing, add 50 parts by weight of nano-BaTiO3 and mix evenly, then add 0.05 parts by weight of 4-dimethylaminopyridine, turn on the heating, keep it at 160℃ and knead for 25h, then turn on the vacuum and keep it at 195℃ and knead for 5h, and then cool to obtain modified BaTiO3.

[0071] The preparation of liquid silicone rubber base type I is the same as in Example 1.

[0072] Comparative Example 3 This comparative example provides a silicone rubber dielectric elastomer material, the raw materials for preparation of which include, by weight, 100 parts of liquid silicone rubber base type I, 50 parts of dimethyl silicone oil (viscosity of 50 cs), 8.5 parts of hydrogenated silicone oil (active hydrogen content of 0.15% by mass, active hydrogen located at both ends and side chains, molar ratio of active hydrogen at both ends to active hydrogen in the side chains of 2:1, viscosity of 25 mPa·s), 50 parts of modified BaTiO3C type, 0.02 parts of ethynyl cyclohexanol and 0.5 parts of a Custer catalyst with a platinum content of 3000 ppm. The modified BaTiO3C type is composed of a first vinyl-terminated polydimethylsiloxane (viscosity of 2000 mPa·s, vinyl content of 0.21%), a first white carbon black (specific surface area of ​​400 g / cm 2 The first vinyl-terminated polydimethylsiloxane, the first silica, the nano-BaTiO3 and the 4-dimethylaminopyridine are prepared in a weight ratio of 100:30:50:0.05.

[0073] The raw materials for preparing liquid silicone rubber base type I are the same as those in Example 1.

[0074] This comparative example also provides a method for preparing the above-mentioned silicone rubber dielectric elastomer material, comprising adding liquid silicone rubber base type I, dimethyl silicone oil, hydrogenated silicone oil, modified BaTiO3C type, and ethynyl cyclohexanol into a planetary mixer, stirring for 1 hour and then unloading the material, and then adding a Custer catalyst with a platinum content of 3000 ppm for vulcanization. The vulcanization temperature is 120°C and the vulcanization time is 25 minutes.

[0075] The preparation of the modified BaTiO3C type includes adding 100 parts by weight of vinyl-terminated polydimethylsiloxane (viscosity of 2000 mPa·s and vinyl content of 0.21%) into an internal mixer, maintaining the speed at 50 Hz, adding 30 parts by weight of the first white carbon black (specific surface area of ​​400 g / cm 2 After mixing, add 50 parts by weight of nano-BaTiO3 and mix evenly, then add 0.05 parts by weight of 4-dimethylaminopyridine, turn on the heating, keep it at 160℃ and knead for 2h, then turn on the vacuum and keep it at 160℃ and knead for 2h, and then cool to obtain modified BaTiO3.

[0076] The preparation method of liquid silicone rubber base type I is the same as that in Example 1.

[0077] Comparative Example 4 This comparative example provides a silicone rubber dielectric elastomer material. The raw materials for preparation, in parts by weight, include 100 parts of liquid silicone rubber base type I, 50 parts of dimethyl silicone oil (viscosity of 50 cs), 8.5 parts of hydrogen-containing silicone oil (active hydrogen content of 0.15% by weight, active hydrogen located at both ends and side chains, with a molar ratio of active hydrogen at both ends to active hydrogen in the side chains of 2:1, and a viscosity of 25 mPa·s), 50 parts of nano-BaTiO3, 0.02 parts of ethynylcyclohexanol, and 0.5 parts of a Custer catalyst having a platinum content of 3000 ppm.

[0078] The raw materials for preparing liquid silicone rubber base type I are the same as those in Example 1.

[0079] This comparative example also provides a method for preparing the above-mentioned silicone rubber dielectric elastomer material, comprising adding liquid silicone rubber base type I, dimethyl silicone oil, hydrogenated silicone oil, nano-BaTiO3, and ethynyl cyclohexanol into a planetary mixer, stirring for 1 hour and then unloading the material, and then adding a Custer catalyst with a platinum content of 3000 ppm for vulcanization. The vulcanization temperature is 120°C and the vulcanization time is 25 minutes.

[0080] The preparation method of liquid silicone rubber base type I is the same as that in Example 1.

[0081] The silicone rubber dielectric elastomer materials prepared in Examples 1 to 6 and Comparative Examples 1 to 4 were tested for viscosity, centrifugal stability, dielectric constant, dielectric loss, and elastic modulus. The test conditions were as follows. The test results are shown in Table 1.

[0082] Viscosity test standard: JJG 1002-2005, the test object is the silicone rubber system vulcanized without the addition of platinum catalyst.

[0083] Dielectric constant and dielectric loss test standard: GB / T 1693-2007.

[0084] Elastic modulus test standard: Dynamic Mechanical Analyzer (DMA).

[0085] Centrifugal stability test method: Centrifuge at 10,000 r / min for 5 minutes. If there is no obvious precipitation, mark "√"; if there is obvious precipitation, mark "×".

[0086] Table 1 Performance test results of Examples 1 to 6 and Comparative Examples 1 to 4

[0087] As can be seen from the test results in Table 1, a comparison of Examples 1-6 and Comparative Examples 1-4 shows that the silicone rubber dielectric elastomer material of the present invention has superior centrifugal stability, indicating that the modified BaTiO3 of the present invention has good compatibility with the silicone rubber system. The overall silicone rubber dielectric elastomer material has a higher dielectric constant, lower dielectric loss, and has more excellent dielectric properties while also having a lower elastic modulus. The silicone rubber dielectric elastomer material of the present invention has a dielectric constant of up to 15.3 and an elastic modulus of 65 kPa or less.

[0088] From the comparison between Example 3 and Comparative Examples 1 and 2, it can be seen that when the first silica is missing or the specific surface area of ​​the first silica is low, the compatibility of the modified BaTiO3 with the silicone rubber system will deteriorate, and the dielectric properties will deteriorate. This may be because silica, especially high specific surface area silica, forms a strong shear force in the system during mixing, accompanied by heat generation. When BaTiO3 is used alone, it cannot form efficient shear, and thus the BaTiO3 nanoparticles cannot be effectively dispersed, and the polysiloxane grafting modification effect deteriorates, thereby affecting its compatibility and dielectric properties.

[0089] From the comparison between Example 3 and Comparative Example 3, it can be seen that further reducing the banburying temperature and banburying time during the preparation of modified BaTiO3 will lead to further deterioration of the dielectric properties and compatibility. This may be because the grafting modification process of BaTiO3 requires a higher temperature and a longer time, otherwise it will lead to low grafting efficiency, thereby affecting the performance of the modified BaTiO3.

[0090] From the comparison between Example 3 and Comparative Example 4, it can be seen that when nano-BaTiO3 is not modified, the polarity of BaTiO3 is extremely poorly compatible with the non-polar system of silicone oil, forming a slurry-like substance with increased viscosity and poor dielectric properties.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit the scope of protection of the present invention. Although the present invention is described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. Silicone rubber dielectric elastomer material, characterized in that, The raw materials for the preparation include, by weight, 100 parts of liquid silicone rubber base, 30 to 150 parts of dimethyl silicone oil, 1 to 10 parts of hydrogenated silicone oil, 10 to 50 parts of modified BaTiO3, 0.02 to 0.1 parts of inhibitor, and 0.5 to 1 parts of platinum catalyst. The modified BaTiO3 is prepared from nano-BaTiO3, a first vinyl-terminated polydimethylsiloxane, and a first white carbon black under the condition of an organic amine catalyst. The first white carbon black has a specific surface area of ​​300 g / cm 2 ~400g / cm 2 of fumed silica.

2. The silicone rubber dielectric elastomer material according to claim 1, wherein The weight ratio of the first vinyl-terminated polydimethylsiloxane, the first white carbon black, the modified BaTiO3, and the organic amine catalyst is 100:30:30~80:0.01~0.

1.

3. The silicone rubber dielectric elastomer material according to claim 2, wherein: The viscosity of the first vinyl-terminated polydimethylsiloxane is 500 mPa·s to 2000 mPa·s, and the organic amine catalyst is selected from at least one of 4-dimethylaminopyridine, 1,8-diazabicycloundec-7-ene, and 1,5-diazabicyclonon-5-ene.

4. The silicone rubber dielectric elastomer material according to claim 1, wherein: The raw materials for preparing the liquid silicone rubber base include 100 parts by weight of a second vinyl-terminated polydimethylsiloxane, 30 to 90 parts by weight of a second white carbon black, 6 to 20 parts by weight of hexamethyldisilazane, and 1 to 2 parts by weight of water.

5. The silicone rubber dielectric elastomer material according to claim 4, wherein: The viscosity of the second vinyl-terminated polydimethylsiloxane is 500 mPa·s to 10000 mPa·s, and the specific surface area of ​​the second white carbon black is 150 g / cm 2 ~400g / cm 2 , the second silica is at least one of fumed silica and precipitated silica.

6. The silicone rubber dielectric elastomer material according to claim 1, wherein: The hydrogen-containing silicone oil is a hydrogen-containing silicone oil in which active hydrogen is located at both ends and side chains, and the mass content of the active hydrogen is 0.1% to 0.2%, and the viscosity is 10mPa·s to 50mPa·s, and / or the hydrogen-containing silicone oil is a hydrogen-containing silicone oil in which active hydrogen is located at the side chains, and the mass content of the active hydrogen is 0.1% to 0.4%, and the viscosity is 30mPa·s to 100mPa·s.

7. The silicone rubber dielectric elastomer material according to claim 1, wherein: The viscosity of the dimethyl silicone oil is 10 cs to 500 cs, the inhibitor is selected from at least one of ethynylcyclohexanol, methylbutynol and tetramethyltetravinylcyclotetrasiloxane, the platinum catalyst is a Custer catalyst or a Speier catalyst, and the platinum element content is 3000 ppm to 5000 ppm.

8. A method for preparing the silicone rubber dielectric elastomer material according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: adding a formulated amount of liquid silicone rubber base, dimethyl silicone oil, hydrogen-containing silicone oil, modified BaTiO3 and an inhibitor into a planetary mixer, stirring the mixture evenly and then adding a platinum catalyst for vulcanization.

9. The silicone rubber dielectric elastomer material according to claim 8, wherein: The preparation of the modified BaTiO3 includes placing the formulated amount of the first vinyl-terminated polydimethylsiloxane, the first white carbon black, the nano-BaTiO3 and the organic amine catalyst in an internal mixer and mixing them evenly, then internally mixing them at 160°C to 195°C for 8h to 25h, and then maintaining the internal mixing at 160°C to 195°C under vacuum conditions for 2h to 5h.

10. The silicone rubber dielectric elastomer material according to claim 8, wherein The preparation of the liquid silicone rubber base comprises placing a formulated amount of a second vinyl-terminated polydimethylsiloxane, a second white carbon black, hexamethyldisilazane and water in an internal mixer and mixing them for 1 to 2 hours, then heating the mixture to 150 to 180° C. and vacuum mixing the mixture for 3 to 6 hours.

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