A high dielectric constant composite material containing disulfide bonds and its preparation method and application

Abstract

The present application discloses a high dielectric constant composite material containing disulfide bonds, its preparation method and application, and belongs to the technical field of high dielectric constant composite materials. The composite material comprises, by weight, 90-100 parts of epoxy resin, 25-35 parts of a curing agent containing disulfide bonds, and 140-170 parts of modified barium titanate; the modified barium titanate is barium titanate surface-modified with a silane coupling agent containing disulfide bonds. The composite material uses a curing agent containing disulfide bonds to cure the epoxy resin, thereby introducing dynamic disulfide bonds into the polymer matrix, and the surface of the modified barium titanate is grafted with a silane coupling agent containing disulfide bonds, which can not only improve the compatibility with the polymer matrix, but also improve the electrical properties of the composite material and give the composite material self-healing properties.

Description

Technical Field

[0001] The present application relates to a high dielectric constant composite material containing disulfide bonds, a preparation method and application thereof, and belongs to the technical field of high dielectric constant composite materials. Background Art

[0002] High-k polymer composites are widely used in advanced electronic devices (such as gate dielectric materials and microcapacitors), energy storage systems (such as thin film capacitors), and advanced insulation systems (such as dielectric functional gradient insulation) due to their unique dielectric properties. Currently, high-k polymer composites are often composed of an organic polymer matrix and inorganic micro-nano fillers. By doping a large amount of micro-nano fillers with high dielectric constants (such as barium titanate and titanium dioxide) into the polymer matrix, the dielectric constant of the material can be significantly improved, resulting in a polymer composite system with a high dielectric constant. However, due to the significant difference in the surface properties of inorganic filler particles and the organic polymer matrix, the filler particles in high-k polymer composites are usually incompatible with the polymer matrix. This results in high dielectric loss and low breakdown strength in high-k polymer composites, which limits the use of high-k polymer composites.

[0003] To address the incompatibility between inorganic fillers and organic polymers, reduce the dielectric loss, and enhance the breakdown field strength of high-k polymer composites, a common approach is to graft and coat the surface of inorganic particles with silane coupling agents, thereby enhancing the compatibility between the inorganic filler and the polymer organic matrix. For example, nano-barium titanate is treated with perfluorosilane (FAS-17) to produce a core-shell structured nano-barium titanate powder (BT@FAS-17) coated with FAS-17. The modified BT@FAS-17 has a reduced surface energy, and the fluorine on the surface of the nanoparticles forms hydrogen bonds with the photosensitive resin molecules, greatly enhancing the compatibility between the inorganic particles and the polymer matrix. BT@FAS-17 significantly improves the dielectric loss and breakdown field strength of high-k composites. However, it does not impart the ability to repair high-k polymer composites, which in turn cannot further extend the service life of related devices and equipment.

[0004] Research has found that by introducing dynamic covalent bonds into polymers without the ability to repair themselves, glass-like polymer materials can be prepared, which can give the polymer the ability to repair itself multiple times. When a large number of dynamic covalent bonds become part of the polymer's cross-linked molecular network, under one or more external stimuli (such as heating, ultraviolet radiation, and pH changes), the dynamic covalent bonds in the cross-linked network will undergo a process of bond breaking-rearrangement-re-bonding, thereby repairing the tiny defects inside the polymer. For example, using 3-furanic acid and maleic anhydride to cure epoxy resin, the Diels-Alder reaction of 3-furanic acid and maleic anhydride is used to introduce reversible dynamic covalent bonds into the epoxy resin cross-linked molecular network, resulting in a glass-like polymer epoxy resin. By heating to above 130°C, the electrical tree damage inside the glass-like polymer epoxy resin can be effectively repaired.

[0005] Although the use of dynamic covalent bonds to construct glass-like polymers can give polymer materials the ability to repair themselves, research on this method has mainly focused on pure, undoped glass-like polymers and has not yet been used to construct repairable High-k polymer composites. This is because High-k composites often require a high content of doped inorganic particles, and high levels of doped inorganic particles often hinder the dynamic covalent bond breaking-rearrangement-rebonding process that occurs during material repair, resulting in a decrease in the repair effect. Therefore, further improvements to related technologies are needed to construct High-k polymer composites with excellent repairability and superior electrical properties. Summary of the Invention

[0006] In order to solve the above problems, a high dielectric constant composite material containing disulfide bonds and a preparation method thereof are provided. By using a disulfide bond-containing curing agent to cure the epoxy resin, dynamic disulfide bonds are introduced into the polymer matrix. The disulfide bonds grafted on the surface of the modified barium titanate can improve the compatibility with the polymer matrix, which can not only improve the electrical properties of the composite material, but also give the composite material self-healing properties.

[0007] According to one aspect of the present application, a high dielectric constant composite material containing disulfide bonds is provided, comprising, by weight, 90-100 parts of epoxy resin, 25-35 parts of a curing agent containing disulfide bonds, and 140-170 parts of modified barium titanate;

[0008] The modified barium titanate is barium titanate whose surface is modified by a silane coupling agent containing a disulfide bond.

[0009] Barium titanate, as a filler, is dispersed in a polymer matrix and can improve the electrical properties of the composite material, giving it lower dielectric loss and higher breakdown field strength. By grafting and coating the barium titanate with a disulfide-containing silane coupling agent, dynamic disulfide bonds are introduced onto the barium titanate surface. This not only improves the compatibility between the barium titanate and the polymer matrix, but also allows the disulfide bonds in the modified barium titanate and polymer matrix to break and then rebuild during the preparation of the composite material, forming an interwoven network containing multiple disulfide bonds in the modified barium titanate and polymer matrix, thus giving the composite material self-healing capabilities.

[0010] The weight fraction of the modified barium titanate can optimize the electrical properties and self-healing properties of the composite material. If the weight fraction is lower than this, the modified barium titanate will not significantly improve the electrical properties and self-healing properties of the composite material. If the weight fraction is higher than this, the modified barium titanate will easily agglomerate in the composite material, thereby deteriorating the compatibility of the modified barium titanate with the polymer matrix, and the mechanical properties and heat resistance of the composite material will decrease.

[0011] Optionally, the disulfide bond-containing curing agent is selected from disulfide bond-containing amine curing agents and / or disulfide bond-containing anhydride curing agents;

[0012] Preferably, the disulfide bond-containing amine curing agent is selected from any one or more of 4,4'-diaminodiphenyl disulfide, 3,3'-diaminodiphenyl disulfide, bis(2-aminophenyl) disulfide, bis(3-fluoro-4-aminophenyl) disulfide, and 4,4'-bis(2-amino-6-methylpyrimidinyl) disulfide, preferably 4,4'-diaminodiphenyl disulfide;

[0013] The disulfide bond-containing acid anhydride curing agent is selected from 3,3'-dithiodipropionic anhydride.

[0014] The above-mentioned curing agent has good dispersibility in epoxy resin, can achieve rapid curing of epoxy resin, and can balance the rigidity and flexibility of the polymer molecular chain, thereby achieving an increase in the glass transition temperature and enhanced self-healing ability of the composite material.

[0015] Under the above-mentioned raw material ratios and types, the composite material has a glass transition temperature greater than 135°C and can self-repair at 140-190°C. The composite material in this application self-repairs at 140-190°C. Firstly, the temperature accelerates the movement of the polymer molecular chains, thereby improving the self-repair efficiency of the composite material. Secondly, it can avoid side reactions such as deformation or degradation of the composite material at high temperatures. However, the composite material contains dynamic disulfide bonds. In fact, at temperatures of 120°C or lower, the dynamic disulfide bonds can still break and rebuild, but at lower temperatures, the self-repair efficiency is slower.

[0016] Optionally, the disulfide-containing silane coupling agent is selected from any one or more of bis-[3-(triethoxysilyl)propyl]-disulfide, bis-[3-(triethoxysilyl)propyl]-tetrasulfide, and 4,4,14,14-tetraethoxy-3,15-dioxa-8,9,10-trithia-4,14-disiloheptadecane.

[0017] The above-mentioned disulfide bond-containing silane coupling agent can further improve the compatibility of barium titanate with the polymer matrix, and can also improve the self-repair efficiency of the composite material. In addition, the raw materials are simple and easy to obtain, suitable for mass production and use, and will not affect the aging resistance, oxidation resistance and degradation resistance of the composite material.

[0018] Optionally, the diameter of the barium titanate is 50 nm to 30 μm, and preferably, the diameter of the barium titanate is no greater than 100 nm. Grafting and coating modification of nano- or micron-sized barium titanate can increase the grafting modification rate of the disulfide-containing silane coupling agent on the barium titanate, thereby improving the coating effect of the disulfide-containing silane coupling agent, thereby improving the self-healing properties of the composite material. Furthermore, the above diameter can improve the dispersibility of the modified barium titanate in the polymer matrix, thereby further improving the compatibility with the polymer matrix and the self-healing properties of the composite material.

[0019] Optionally, the composite material has a dielectric constant of 12-14, a power frequency dielectric loss of 0.015-0.02, and a volume resistivity of 1.4×10 15 -1.8×10 15 Ω·cm, and the electric field strength is 25-30kV / mm.

[0020] According to another aspect of the present application, a method for preparing the high dielectric constant composite material containing disulfide bonds as described above is provided, comprising the following steps:

[0021] (1) weighing the epoxy resin, the disulfide bond-containing curing agent, and the modified barium titanate in proportion, and mixing them to obtain a mixture;

[0022] (2) The mixture is poured into a mold, pre-cured at 70-90° C. for 5-7 hours, and then vacuum-cured at 110-130° C. for 10-14 hours to obtain the high dielectric constant composite material containing disulfide bonds.

[0023] The three raw materials are mixed to obtain a mixture, in which the three raw materials are evenly dispersed and form a uniform raw material body. At the pre-curing temperature, the curing agent containing disulfide bonds reacts with the epoxy resin to form a polymer network, and the modified barium titanate is evenly dispersed in the polymer network. After pre-curing, the composite material is initially shaped. The vacuum curing of the composite material can further improve the shaping property of the composite material. The re-curing under vacuum and at 110-130°C can, on the one hand, cause the disulfide bonds in the polymer matrix and the disulfide bonds on the surface of the modified barium titanate to break and then form a bond, thereby forming an interwoven three-dimensional network between the modified barium titanate and the polymer matrix, thereby improving the self-repairing performance and electrical properties of the composite material, and on the other hand, can prevent the composite material from undergoing side reactions such as aging or decomposition, thereby extending the service life of the composite material.

[0024] Optionally, the modification step of the modified barium titanate is:

[0025] Mixing a disulfide bond-containing silane coupling agent with ethanol, water, and a pH adjuster to obtain a mixture A, wherein the pH of the mixture A is 2-4, and ultrasonicating the mixture A at 25-35° C. for 10-15 hours to obtain a silane coupling agent hydrolyzate;

[0026] Dispersing barium titanate in ethanol by ultrasonication for 1-3 hours to obtain a barium titanate dispersion;

[0027] Mixing the silane coupling agent hydrolyzate and the barium titanate dispersion, stirring at 60-80° C. for 6-8 hours to obtain a mixture B;

[0028] The mixture B is centrifuged, washed, dried and sieved to obtain the modified barium titanate.

[0029] Ethanol and water are used as solvents for the silane coupling agent mixture A. Ethanol can improve the dispersibility of the silane coupling agent containing a disulfide bond, and water can hydrolyze the silane coupling agent containing a disulfide bond at 25-35° C. to obtain silanol. The pH of the mixture A is 2-4, which can avoid the silanol condensation after hydrolysis and increase the silanol content in the silane coupling agent hydrolyzate, thereby ensuring the modification effect on barium titanate; at the same time, it can avoid the acid residue caused by excessive acidity affecting the electrical properties of the composite material, thereby causing the resistivity and breakdown voltage to decrease and the loss to increase.

[0030] Optionally, the weight ratio of ethanol, water and disulfide-containing silane coupling agent in the mixture A is 80-100:8-15:2-3; the above weight ratio can make the disulfide-containing silane coupling agent uniformly dispersed in the mixture A, and the weight of water can increase the hydrolysis efficiency of the disulfide-containing silane coupling agent and the amount of silanol after hydrolysis.

[0031] The disulfide-bonded silane coupling agent in the silane coupling agent hydrolyzate accounts for 4% to 6% of the weight of the barium titanate in the nano-barium titanate dispersion. The weight of the disulfide-bonded silane coupling agent can improve the coating and modification effect of the barium titanate, promote the rapid compatibility of the modified barium titanate with the polymer matrix, and improve the electrical properties and heat resistance of the composite material. In combination with the diameter of the modified barium titanate, the disulfide-bonded silane coupling agent can also improve the uniformity of the dispersion on the surface of the barium titanate. When the modified barium titanate and the polymer matrix are broken and then reconstructed, the dynamic disulfide bonds can also be evenly distributed in the polymer network, thereby improving the self-repairing ability of the composite material. If the content of the silane coupling agent containing disulfide bonds is too low, the electrical properties and self-healing properties of the composite material will not be significantly improved. If the content of the silane coupling agent containing disulfide bonds is too high, firstly, it will lead to an increase in cost. In the grafting process, about 6% of the silane coupling agent containing disulfide bonds is grafted, and more silane coupling agent containing disulfide bonds will cause waste of raw materials. Secondly, if the content of the silane coupling agent containing disulfide bonds is too high, the residual small molecule coupling agent in the subsequent treatment will not be washed cleanly, which will also affect the electrical properties of the composite material, resulting in a decrease in resistivity and breakdown voltage and an increase in loss.

[0032] Optionally, the pH adjuster is selected from any one or more of glacial acetic acid, silicic acid, nitrous acid, hydrofluoric acid, hypochlorous acid, hydrocyanic acid, sulfurous acid, propionic acid, citric acid, maleic acid, phosphoric acid, and polyphosphoric acid. The pH adjuster has a relatively weak acidity and can quickly adjust the pH of the mixture A to an appropriate range, thereby ensuring that the disulfide bond-containing silane coupling agent is quickly hydrolyzed into silanols and preventing the condensation of the silanols.

[0033] According to another aspect of the present application, provided are the applications of the composite materials prepared by the high dielectric constant composite materials containing disulfide bonds described in any of the above items and the preparation methods of the high dielectric constant composite materials containing disulfide bonds described in any of the above items in electronic devices, energy storage systems and insulation systems.

[0034] Optionally, the electronic device includes a gate dielectric material and a microcapacitor, the energy storage system includes a thin film capacitor, and the insulation system includes dielectric functional gradient insulation.

[0035] The beneficial effects of this application include but are not limited to:

[0036] 1. According to the high dielectric constant composite material containing disulfide bonds of the present application, the composite material in which modified barium titanate is used as a filler and combined with a curing agent containing disulfide bonds has high repairability while ensuring that it has excellent electrical properties and heat resistance.

[0037] 2. According to the high dielectric constant composite material containing disulfide bonds of the present application, modified barium titanate modified with a disulfide bond-containing silane coupling agent is used as an inorganic filler, which can minimize the impact of high content of inorganic fillers on the repair performance of the composite material and improve the repair efficiency of the composite material.

[0038] 3. According to the high dielectric constant composite material containing disulfide bonds in the present application, the disulfide bond-containing silane coupling agent and disulfide bond-containing curing agent selected in the raw materials have large-scale industrial production capacity, and there is no need to rebuild a complex synthesis production line. The preparation method is simple and has the potential for industrial application.

[0039] 4. According to the preparation method of the high dielectric constant composite material containing disulfide bonds of the present application, during the curing molding, the disulfide bonds on the surface of the modified nano-barium titanate particles are bonded with the disulfide bonds in the polymer matrix, which greatly improves the compatibility and bonding ability between the inorganic filler and the polymer matrix, thereby improving the macroscopic performance of the high dielectric constant composite material, so that the composite material has lower dielectric loss, higher breakdown field strength and higher glass transition temperature. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] 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:

[0041] Figure 1 This is a schematic diagram of the composite material 1# involved in Example 1 of the present application before and after self-repair.

[0042] Figure 2 This is the electrical test diagram of composite material 1# involved in Example 1 of this application. DETAILED DESCRIPTION

[0043] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0044] Unless otherwise specified, the raw materials in the examples of this application were purchased through commercial channels.

[0045] Example 1

[0046] This embodiment relates to the preparation of a high dielectric constant composite material containing disulfide bonds, as follows:

[0047] Preparation of modified barium titanate:

[0048] S1: 4.0 g of bis-[3-(triethoxysilyl)propyl]-disulfide was mixed with 180.0 g of ethanol and 20.0 g of water, and the pH was adjusted to 2-4 with glacial acetic acid to obtain a mixture A, wherein the weight ratio of ethanol, water and bis-[3-(triethoxysilyl)propyl]-disulfide in the mixture A was 90:10:2;

[0049] S2: ultrasonically hydrolyze the mixture A at 35°C for 12 h to obtain a silane coupling agent hydrolyzate;

[0050] S3: dispersing 100.0 g of barium titanate with a diameter of 80 nm in 300.0 g of ethanol and ultrasonically dispersing for 2 h to obtain a barium titanate dispersion;

[0051] S4: mixing the silane coupling agent hydrolyzate with the barium titanate dispersion, wherein the disulfide bond-containing silane coupling agent accounts for 4% of the weight of the barium titanate, and stirring the mixture at a constant temperature of 80° C. for 6 hours to obtain a mixture B;

[0052] S5: Centrifuge, wash, dry and sieve the mixture B to obtain modified barium titanate.

[0053] Manufacturing of high dielectric constant composite materials:

[0054] (1) By weight, 100 parts of epoxy resin, 31 parts of 4,4'-diaminodiphenyl disulfide, and 164 parts of the modified barium titanate prepared in step S5 were mechanically stirred and uniformly mixed in a planetary mixer to obtain a mixture;

[0055] (2) The mixture was poured into a mold, pre-cured at 80°C for 6 h, and then vacuum-cured at 120°C for 12 h to obtain composite material 1#.

[0056] Example 2

[0057] This embodiment relates to the preparation of a high dielectric constant composite material containing disulfide bonds, as follows:

[0058] Preparation of modified barium titanate:

[0059] S1: 6.0 g of bis-[3-(triethoxysilyl)propyl]-tetrasulfide was mixed with 160.0 g of ethanol and 30.0 g of water, and the pH was adjusted to 2-4 with nitrous acid to obtain a mixture A, wherein the weight ratio of ethanol, water and bis-[3-(triethoxysilyl)propyl]-disulfide in the mixture A was 80:15:3;

[0060] S2: Ultrasonic hydrolysis of mixture A at 25°C for 15 h to obtain a silane coupling agent hydrolyzate;

[0061] S3: dispersing 100.0 g of barium titanate with a diameter of 30 μm into 200.0 g of ethanol and ultrasonically dispersing for 2 h to obtain a barium titanate dispersion;

[0062] S4: mixing the silane coupling agent hydrolyzate with the barium titanate dispersion, wherein the disulfide bond-containing silane coupling agent accounts for 6% of the weight of the barium titanate, and stirring the mixture at a constant temperature of 60° C. for 8 hours to obtain a mixture B;

[0063] S5: Centrifuge, wash, dry and sieve the mixture B to obtain modified barium titanate.

[0064] Manufacturing of high dielectric constant composite materials:

[0065] (1) 90 parts by weight of epoxy resin, 25 parts of 3,3'-dithiodipropionic anhydride, and 140 parts of the modified barium titanate prepared in step S5 were mechanically stirred and uniformly mixed in a planetary mixer to obtain a mixture;

[0066] (2) The mixture was poured into a mold, pre-cured at 70°C for 7 h, and then vacuum-cured at 110°C for 14 h to obtain composite material 2#.

[0067] Example 3

[0068] This embodiment relates to the preparation of a high dielectric constant composite material containing disulfide bonds, as follows:

[0069] Preparation of modified barium titanate:

[0070] S1: 4.0 g of 4,4,14,14-tetraethoxy-3,15-dioxa-8,9,10-trithia-4,14-disiloheptadecane was mixed with 200.0 g of ethanol and 16.0 g of water, and the pH was adjusted to 2-4 with citric acid to obtain a mixture A, wherein the weight ratio of ethanol, water and bis-[3-(triethoxysilyl)propyl]-disulfide in the mixture A was 100:8:2;

[0071] S2: Ultrasonic hydrolysis of mixture A at 30°C for 14 h to obtain a silane coupling agent hydrolyzate;

[0072] S3: dispersing 100.0 g of barium titanate with a diameter of 100 nm into 200.0 g of ethanol and ultrasonically dispersing for 2 h to obtain a barium titanate dispersion;

[0073] S4: mixing the silane coupling agent hydrolyzate with the barium titanate dispersion, wherein the disulfide bond-containing silane coupling agent accounts for 4% of the weight of the barium titanate, and stirring the mixture at a constant temperature of 70° C. for 7 hours to obtain a mixture B;

[0074] S5: Centrifuge, wash, dry and sieve the mixture B to obtain modified barium titanate.

[0075] Manufacturing of high dielectric constant composite materials:

[0076] (1) mechanically stirring and uniformly mixing, by weight, 100 parts of epoxy resin, 35 parts of 3,3'-diaminodiphenyl disulfide, and 170 parts of the modified barium titanate prepared in step S5 in a planetary mixer to obtain a mixture;

[0077] (2) The mixture was poured into a mold, pre-cured at 90°C for 5 h, and then vacuum-cured at 130°C for 10 h to obtain composite material 3#.

[0078] Example 4

[0079] The difference between this embodiment and embodiment 1 is that in step S1, the pH of mixture A is 4.5, and the remaining steps are the same as those in embodiment 1 to obtain composite material 4#.

[0080] Example 5

[0081] The difference between this embodiment and Example 1 is that in step S1, the weight of ethanol is 100.0 g and the weight of water is 100.0 g, so the weight ratio of ethanol, water and disulfide bond-containing silane coupling agent in mixture A is 50:50:2. The remaining steps are the same as in Example 1 to obtain composite material 5#.

[0082] Example 6

[0083] The difference between this embodiment and Example 1 is that: in step S1, the weight of bis-[3-(triethoxysilyl)propyl]-disulfide is 2.0 g, the weight of ethanol is 90.0 g, and the weight of water is 10.0 g. The disulfide-containing silane coupling agent accounts for 2% of the weight of barium titanate. The weight ratio of ethanol, water, and disulfide-containing silane coupling agent in mixture A is the same as that in Example 1. The remaining steps are the same as those in Example 1, and composite material 6# is obtained.

[0084] Example 7

[0085] The difference between this embodiment and embodiment 1 is that in step S3, the diameter of the barium titanate is 40 μm, and the remaining steps are the same as those in embodiment 1, to obtain composite material 7#.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 1 is that 1,6-hexanediamine is used to replace 4,4'-diaminodiphenyl disulfide, and the remaining steps are the same as those in Example 1 to obtain a comparative composite material D1#.

[0088] Comparative Example 2

[0089] The difference between this comparative example and Example 1 is that perfluorosilane (FAS-17) is used to replace bis-[3-(triethoxysilyl)propyl]-disulfide, and the remaining steps are the same as Example 1 to obtain a comparative composite material D2#.

[0090] Comparative Example 3

[0091] The difference between this comparative example and Example 1 is that in step (1), the number of modified barium titanate is 200 parts, and the remaining steps are the same as in Example 1, to obtain a comparative composite material D3#.

[0092] Test Example 1: Electrical Properties and Glass Transition Temperature

[0093] The electrical properties of the composite materials prepared in the above examples and comparative examples were tested, and the dielectric spectra (dielectric constant and dielectric loss) were measured using a high-temperature, high-voltage, broadband dielectric impedance spectrometer (Novocontrol Concept 43): the effective value of the measurement voltage was 1 kV, no DC bias was applied, and the measurement frequency range was 0.1 Hz to 10 kHz.

[0094] The volume resistivity measurement system consists of an 8009 three-electrode fixture and a Keithley 6517b electrometer, where the measurement voltage is 1000 V and the sample thickness is about 1 mm.

[0095] The sample thickness used to measure the breakdown field strength was 1 mm, and the experimental method was based on GB / T 1408.1-2016. The test electrode used was a 25 mm diameter ball-to-ball electrode, and the test was conducted in insulating oil.

[0096] Glass transition temperature (T g ) was tested by DSC, the test temperature was from room temperature to 220℃, the heating rate was 10℃ / min, and the test was carried out in a nitrogen atmosphere. The T g The dielectric constant, dielectric loss, volume resistivity and breakdown probability test graph of composite material 1# are shown in the figure below. Figure 2 .

[0097] according to Figure 2 It can be seen that the dielectric constant of composite material 1# is about 12.7, the power frequency dielectric loss is about 0.018, and the volume resistivity is about 1.63×10 15 Ω·cm, and the electric field strength is about 27.1kV / mm.

[0098] Compared with composite material 1#, composite material 2# has similar Tg, slightly lower dielectric constant, slightly higher dielectric loss, similar volume resistivity, and similar dielectric strength;

[0099] Compared with composite material 1#, composite material 3# has a slightly lower Tg, similar dielectric constant, slightly increased dielectric loss, slightly decreased volume resistivity, and slightly decreased dielectric strength.

[0100] Compared with composite material 1#, the pH of composite material 4# increases, which easily leads to an increase in residual impurity ions in the composite material, resulting in an increase in dielectric loss and a decrease in volume resistivity.

[0101] Compared with composite material 1#, the weight ratio of ethanol, water and disulfide-containing silane coupling agent in mixture A was changed, which caused the success rate of silane coupling agent grafting modification to decrease, resulting in increased dielectric loss, decreased volume resistivity and decreased dielectric strength.

[0102] Compared with composite material 1#, the amount of disulfide bond-containing silane coupling agent in composite material 6# decreased, which caused incomplete grafting of barium titanate particles, resulting in increased dielectric loss, decreased volume resistivity, and decreased dielectric strength;

[0103] Compared with composite material 1#, composite material 7# has an increased barium sulfate diameter, which causes a decrease in filler specific surface area and a weakening of the modification effect, resulting in a decrease in Tg, a decrease in dielectric constant, and an increase in dielectric loss.

[0104] Compared with composite material 1#, comparative composite material D1# and comparative composite material D2# use silane coupling agents that do not contain disulfide bonds, which causes the compatibility between the matrix and filler to deteriorate, resulting in a decrease in Tg, an increase in dielectric loss, and a decrease in volume resistivity;

[0105] Comparing composite material D3# with composite material 1#, the increase in the amount of modified barium sulfate leads to an increase in filler content, resulting in an increase in dielectric constant, an increase in dielectric loss, a decrease in volume resistivity, and a decrease in dielectric strength;

[0106] Test Example 2: Self-repair performance

[0107] Taking composite material 1#, comparative composite material D1#, comparative composite material D2# and comparative composite material D3# as examples, the self-healing effect was verified. The composite materials with micron-level scratch damage on the surface were treated at 150°C for 6 hours, and the self-healing effect of each composite material was observed.

[0108] Figure 1 This is a comparison of composite material 1# before and after repair. It can be seen that among the four damaged scratches, two have been almost completely repaired, and the other two have been repaired from 79.6μm and 49.9μm to 42.8μm and 33.6μm, with significant repair effects.

[0109] Comparative composite materials D1# and D2# use silane coupling agents that do not contain disulfide bonds, which causes a decrease in the dynamic disulfide bond content and leads to a decrease in the self-healing performance of the composite materials.

[0110] Comparing composite material D3# with composite material 1#, the increase in the amount of modified barium sulfate causes an increase in the filler content. The filler restricts the exchange and rearrangement between dynamic covalent bonds, resulting in a decrease in the self-healing performance of the composite material.

[0111] According to the above-mentioned Test Examples 1 and 2, it can be seen that the composite material prepared in this application not only has high electrical properties, but can also self-repair by heating when damaged, thereby improving the service life of devices prepared from the composite material.

[0112] The foregoing is merely an embodiment of the present application, and the scope of protection 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 may have various modifications and variations. Any modifications, equivalent substitutions, improvements, etc. made within the technical ideas and principles of the present application should be included in the scope of protection of the present application.

Claims

1. A high dielectric constant composite material containing disulfide bonds, characterized in that: Calculated by weight, it includes 90-100 parts of epoxy resin, 25-35 parts of disulfide bond-containing curing agent and 140-170 parts of modified barium titanate; The modified barium titanate is barium titanate whose surface is modified by a silane coupling agent containing a disulfide bond; The disulfide bond-containing curing agent is selected from an amine curing agent containing a disulfide bond and / or an acid anhydride curing agent containing a disulfide bond; the disulfide bond-containing amine curing agent is selected from any one or more of 4,4'-diaminodiphenyl disulfide, 3,3'-diaminodiphenyl disulfide, bis(2-aminophenyl) disulfide, bis(3-fluoro-4-aminophenyl) disulfide, and 4,4'-bis(2-amino-6-methylpyrimidinyl) disulfide; the disulfide bond-containing acid anhydride curing agent is selected from 3,3'-dithiodipropionic anhydride; The disulfide-bonded silane coupling agent is selected from any one or more of bis-[3-(triethoxysilyl)propyl]-disulfide, bis-[3-(triethoxysilyl)propyl]-tetrasulfide, and 4,4,14,14-tetraethoxy-3,15-dioxa-8,9,10-trithia-4,14-disiloheptadecane.

2. The high dielectric constant composite material containing disulfide bonds according to claim 1, characterized in that The diameter of the barium titanate is 50 nm-30 μm.

3. The high dielectric constant composite material containing disulfide bonds according to claim 2, characterized in that The diameter of the barium titanate is no greater than 100 nm.

4. The high dielectric constant composite material containing disulfide bonds according to claim 1, characterized in that The dielectric constant of the composite material is 12-14, the power frequency dielectric loss is 0.015-0.02, and the volume resistivity is 1.4×10 15 -1.8×10 15 Ω·cm, and the electric field strength is 25-30kV / mm.

5. The method for preparing a high dielectric constant composite material containing disulfide bonds according to any one of claims 1 to 4, characterized in that: The steps include: (1) weighing the epoxy resin, the disulfide bond-containing curing agent, and the modified barium titanate in proportion, and mixing them to obtain a mixture; (2) The mixture is poured into a mold, pre-cured at 70-90° C. for 5-7 hours, and then vacuum-cured at 110-130° C. for 10-14 hours to obtain the high dielectric constant composite material containing disulfide bonds.

6. The preparation method according to claim 5, characterized in that The modification steps of the modified barium titanate are: Mixing a disulfide bond-containing silane coupling agent with ethanol, water, and a pH adjuster to obtain a mixture A, wherein the pH of the mixture A is 2-4, and ultrasonicating the mixture A at 25-35° C. for 10-15 hours to obtain a silane coupling agent hydrolyzate; Dispersing barium titanate in ethanol by ultrasonication for 0.5-2h to obtain a barium titanate dispersion; Mixing the silane coupling agent hydrolyzate and the barium titanate dispersion, stirring at 60-80° C. for 5-8 hours to obtain a mixture B; The mixture B is centrifuged, washed, dried and sieved to obtain the modified barium titanate.

7. The preparation method according to claim 6, characterized in that The weight ratio of ethanol, water and disulfide bond-containing silane coupling agent in the mixture A is 80-100:8-15:2-3; The silane coupling agent containing disulfide bonds in the silane coupling agent hydrolyzate accounts for 4% to 6% of the weight of the barium titanate in the nano-barium titanate dispersion.

8. The preparation method according to claim 6, characterized in that The pH regulator is selected from any one or more of glacial acetic acid, silicic acid, nitrous acid, hydrofluoric acid, hypochlorous acid, hydrocyanic acid, sulfurous acid, propionic acid, citric acid, maleic acid, phosphoric acid, and polyphosphoric acid.

9. Use of the high dielectric constant composite material containing disulfide bonds according to any one of claims 1 to 4 and the composite material prepared by the method for preparing the high dielectric constant composite material containing disulfide bonds according to any one of claims 5 to 8 in electronic devices, energy storage systems and insulation systems.

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