High-temperature-resistant high-dielectric silica gel composite material and preparation method thereof

Abstract

The invention provides a high-temperature-resistant high-dielectric silica gel composite material and a preparation method thereof.The preparation method comprises the steps that in the inert atmosphere, an aza-aryl silylene monomer and a siloxane chain segment monomer are mixed according to the molar ratio, a catalyst is added, a reaction is conducted for 3-6 hours at the temperature of 150-180 DEG C, and an elastic prepolymer is prepared; the preparation method comprises the following steps: preparing a boron-functionalized zirconium-titanium nitride nanosheet by adopting a plasma stripping method, carrying out surface treatment on the boron-functionalized zirconium-titanium nitride nanosheet, and introducing a fluorine-boron functional group to obtain a superlattice phase-change nanosheet; performing ultrasonic treatment on the superlattice phase-change nanosheets and a difunctional fluorosilicone phosphamide interface regulating agent in anhydrous acetonitrile for 30 minutes to obtain a suspension, adding the suspension into the elastic prepolymer, stirring at 60 DEG C for 2 hours to form composite slurry, and performing thermocuring on the composite slurry to obtain the high-temperature-resistant high-dielectric silica gel composite material. Therefore, the high dielectric constant of the composite material is realized and the high-temperature resistance is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic thermal conductive materials, and in particular relates to a high-temperature resistant high-dielectric silica gel composite material and a preparation method thereof. Background Art

[0002] In electronic devices, silicone (or silicone rubber, silicone gel, silicone glue, etc.) plays a very wide range of roles. On the one hand, by filling with high thermal conductivity fillers such as alumina, boron nitride, and graphene, silicone can be made into thermally conductive gaskets or thermally conductive potting glue to achieve heat conduction between the electronic device chip and the heat sink, reduce the temperature rise of the device, and ensure working stability. However, the temperature resistance limit of conventional composite silicone is 200~250℃, and the long-term use temperature usually does not exceed 150~180℃. At high temperatures (>250℃), although the siloxane segment (Si-O-Si) is more stable than the CC bond, the flexibility of the segment leads to thermal deformation and mechanical strength degradation. At extreme temperatures (>300℃), thermal oxidative degradation, surface cracking, and loss of elasticity will occur, limiting its application in scenarios such as high-power devices, silicon carbide chips, and IGBT packaging. On the other hand, the volume resistivity of silicone is high (10¹³~10¹ 6 Ω·cm), with a high breakdown voltage, effectively isolates electrical contacts between circuit components, preventing short circuits and leakage. However, the dielectric constant of conventional silicone is only 2.7-3.5 (at 1MHz), significantly lower than that of ceramic dielectric materials (>100) and polyimide (3.5-4.5). This weak dielectric polarization limits its energy storage capacity under electric fields, creating a performance bottleneck in silicon carbide chips and high-power devices (such as 5G RF, energy storage capacitors, and flexible electronics). Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a high-temperature resistant and high-dielectric silicone composite material and a preparation method thereof, aiming to solve the problems of poor high-temperature resistance and weak dielectric polarization ability of silicone materials.

[0004] To solve the above problems, the present invention proposes a method for preparing a high-temperature resistant and high-dielectric silicone composite material, comprising the following steps: S1. Under an inert atmosphere, a nitrogen heteroaromatic silene monomer and a siloxane segment monomer are mixed in a molar ratio, a catalyst is added, and the mixture is reacted at 150-180° C. for 3-6 hours to prepare an elastic prepolymer; S2. preparing boron-functionalized zirconium titanium nitride nanosheets by plasma stripping, surface treating the boron-functionalized zirconium titanium nitride nanosheets, introducing fluorine-boron functional groups, and obtaining superlattice phase change nanosheets; S3. Ultrasonicate the superlattice phase change nanosheets and the bifunctional fluorosilicon phosphoramide interface regulator in anhydrous acetonitrile for 30 minutes to obtain a suspension, add the suspension to the elastic prepolymer, stir at 60°C for 2 hours to form a composite slurry, and thermally cure the composite slurry to obtain a high-temperature resistant and high-dielectric silicone composite material.

[0005] In some embodiments, in step S1, the nitrogen heteroaromatic silene monomer includes at least one of 3,6-diamino-1,2,4-triazacyclosilene, 2-(aminophenyl)-tetraazasilicon-fused cycloolefin, and bis(3-aminopyridyl)silene; the siloxane segment monomer includes at least one of aminopropyl-terminated polydimethylsiloxane, phenylethyl-terminated polyphenylsiloxane, and diaminoethyl-terminated polymethylfluorosiloxane; the molar ratio of the nitrogen heteroaromatic silene monomer:siloxane segment monomer is 1:3; and the catalyst includes at least one of cerium heteropoly phosphotungstate, dichlorobis(dimethylamino)silane zirconium complex, and lanthanum trifluoromethanesulfonate.

[0006] In some embodiments, step S1 includes: S1.1. Degas the nitrogen heteroarylsilene monomer and the siloxane segment monomer separately at 120° C. under vacuum for 1 hour, and premix the nitrogen heteroarylsilene monomer and the siloxane segment monomer at room temperature for 30 minutes using ultrasonic dispersion and magnetic stirring to obtain a premix; S1.2. Transfer the premix into the reactor and continue to introduce nitrogen gas, with the outlet of the nitrogen connected to the alkaline absorption liquid. The nitrogen flow rate is 100-200 mL / min. Set the heating rate to 5°C / min. When the temperature reaches 150-180°C, adjust the nitrogen flow rate to 50-100 mL / min. Keep the reaction warm for 3-6 hours while stirring at 200 rpm. S1.3. Real-time monitoring of the viscosity of the premixture. When the real-time viscosity of the premixture rises to twice the initial viscosity of the premixture, stirring and heating are stopped. S1.4. Cool the mixture to 80°C, stop introducing nitrogen and slowly release it, add a capping agent and perform rotary evaporation to obtain an elastic prepolymer.

[0007] In some embodiments, before step S1.1, the method further includes: Dissolve cyanuric chloride in anhydrous toluene, stir and cool to 0°C, add a mixture of 3-aminophenyltrichlorosilane and anhydrous pyridine dropwise at a rate of 1 mL / min, heat to 70°C after the addition is complete, and reflux for 12 hours to obtain an azoaromatic ring-silicon chloride precursor; After the reaction is completed, the mixture is cooled to room temperature, deionized water is added and filtered, the filtered solution is rotary evaporated, and purified by column chromatography to obtain an azaarylsilene monomer; In a three-necked flask, add octamethylcyclotetrasiloxane and toluene, introduce nitrogen, then add p-toluenesulfonic acid, raise the temperature to 80°C, and stir for 2 hours to generate siloxane segments; γ-Aminopropyltriethoxysilane and phenethyltriethoxysilane are added dropwise to the siloxane segment and the reaction is continued for 4 hours. After the reaction is completed, a neutralization catalyst is added and rotary evaporation is performed to obtain a siloxane segment monomer, wherein the neutralization catalyst includes at least one of anhydrous triethylamine, anhydrous sodium bicarbonate, and aniline.

[0008] In some embodiments, step S2 includes: S2.1. Placing a zirconium titanium nitride substrate in a plasma reaction chamber, introducing an argon-nitrogen mixed gas, exciting the plasma, and then introducing boronization gas. The reaction time is 2-4 hours, and after the reaction is completed, boron-functionalized zirconium titanium nitride nanosheets are obtained. The plasma power is 180-220 W, and the reaction temperature is 220-240°C. S2.2. Place the boron-functionalized zirconium titanium nitride nanosheets in a quartz boat in a tube furnace, heat to 250°C, pretreat in an argon atmosphere for 30 minutes, raise the temperature to 300°C, introduce fluorine gas and react with aminoborane for 1 hour to obtain superlattice phase change nanosheets.

[0009] In some embodiments, in step S2, the zirconium titanium nitride substrate includes at least one of a zirconium titanium nitride solid solution, a zirconium titanium aluminum nitride composite, and a zirconium titanium boron nitride composite; the boron-functionalized zirconium titanium nitride nanosheets include at least one of a zirconium titanium nitride-doped fluoroborene nanosheets, an aluminum-doped fluoroborene layered zirconium titanium nitride nanosheets, and a boron-doped zirconium titanium nitride nanosheets; the flow ratio of argon:nitrogen:boride gas is (75~80):(15~20):5; the boride gas includes at least one of boron trifluoride and diborane; and the fluoride gas includes at least one of boron trifluoride, hexafluoroethane, and carbon tetrafluoride.

[0010] In some embodiments, step S3 includes: S3.1. Adding superlattice phase change nanosheets and a bifunctional fluorosilicic acid phosphoramide interface modulator to acetonitrile and dispersing the superlattice phase change nanosheets with a 1-minute pause for every 5 minutes to obtain a coating suspension, wherein the mass ratio of superlattice phase change nanosheets to bifunctional fluorosilicic acid phosphoramide interface modulator is (1-2):10; S3.2. Add the coating suspension dropwise to the elastic prepolymer preheated to 60°C at a rate of 1 mL / min. Stir continuously for 2 hours at a stirring speed of 300 rpm to obtain a composite slurry. S3.3. Place the composite slurry in a gradient temperature mold with an upper mold temperature of 350°C and a lower mold temperature of 250°C. Adjust the internal pressure to 20 MPa and maintain for 30 minutes. Cool to room temperature and then demould to obtain a composite body. S3.4. Place the composite material blank in a radio frequency plasma reactor, introduce a nitrogen-fluorine mixed gas, the plasma power is 300 W, and the reaction time is 10 minutes to obtain a high-temperature resistant and high-dielectric silicone composite material, wherein the nitrogen-fluorine mixed gas includes nitrogen and carbon tetrafluoride, and the flow ratio of nitrogen:carbon tetrafluoride is 3:1.

[0011] In some embodiments, before step S3.1, step S3 further includes: 0.1 mol of diphenylphosphoryl chloride was dissolved in 200 mL of acetonitrile and cooled to 0°C. A mixture of 0.1 mol of trifluoropropyltriethoxysilane and 0.12 mol of anhydrous pyridine was added dropwise at a drop rate of 1 mL / min. The reaction temperature was raised to 40°C and stirred for 6 hours. After stirring, the mixture was filtered and rotary evaporated, and then purified by silica gel column chromatography to obtain a bifunctional fluorosilicylphosphoramide interface regulator. The silica gel column was filled with petroleum ether and ethyl acetate, and the mass ratio of petroleum ether to ethyl acetate was 4:1.

[0012] The present invention provides a high-temperature resistant high-dielectric silicone composite material, which is prepared by the above-mentioned preparation method of the high-temperature resistant high-dielectric silicone composite material. The high-temperature resistant high-dielectric silicone composite material includes an elastic prepolymer and a superlattice phase change nanosheet; wherein, The elastic prepolymer is used as the main skeleton of the high-temperature resistant and high-dielectric silicone composite material; The superlattice phase change nanosheet is used to improve the dielectric constant of the high-temperature resistant and high-dielectric silicone composite material.

[0013] Compared with the prior art, the high-temperature resistant and high-dielectric silicone composite material and its preparation method in the present invention have the following beneficial effects: The present invention systematically improves the high temperature resistance and dielectric properties of silicone composite materials from the molecular, interface to structural levels through the collaborative design of nitrogen heteroaromatic silicene-siloxane elastic prepolymer, superlattice phase change nanosheet and bifunctional fluorosilicone phosphoramide interface regulator. The introduction of nitrogen heteroaromatic rings and Si-N bonds into the elastic prepolymer enhances the thermal stability and polarization ability of the main chain, overcoming the defects of traditional siloxane segments that are soft, easily degraded and have poor polarization response. The superlattice phase change nanosheet is based on zirconium titanium nitride, combined with boron functionalization and fluoroboron synergistic doping, to provide high thermal stability and adjustable polarization behavior, significantly improve the dielectric constant through interface polarization and phase change effects, and inhibit charge recombination. The bifunctional fluorosilicone phosphoramide strengthens the interface bonding through the phosphoramide group, and the trifluoropropyl group reduces the interface energy, relieves thermal stress, inhibits interface debonding, and ensures structural stability and electrical performance consistency under high temperature environment. Finally, through orderly thermal curing and surface fluorine nitrogen plasma modification, material densification, polarization channel optimization and corrosion resistance enhancement are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The figure is a flow chart of a method for preparing a high-temperature resistant and high-dielectric silicone composite material according to an embodiment of the present invention. DETAILED DESCRIPTION

[0015] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0016] The "material" in the specification generally refers to "high-temperature resistant and high-dielectric silicone composite material". Unless otherwise specified, it is an abbreviation.

[0017] Please refer to Figure 1 The present invention provides a method for preparing a high-temperature resistant and high-dielectric silicone composite material, the steps comprising: S1. Under an inert atmosphere, a nitrogen heteroaromatic silene monomer and a siloxane segment monomer are mixed in a molar ratio, a catalyst is added, and the mixture is reacted at 150-180° C. for 3-6 hours to obtain an elastic prepolymer.

[0018] In step S1, the nitrogen heteroaromatic silene monomer includes at least one of 3,6-diamino-1,2,4-triazacyclosilene, 2-(aminophenyl)-tetraazasilicon-fused cycloene, and bis(3-aminopyridyl)silene; the siloxane segment monomer includes at least one of aminopropyl-terminated polydimethylsiloxane, phenylethyl-terminated polyphenylsiloxane, and diaminoethyl-terminated polymethylfluorosiloxane; the molar ratio of the nitrogen heteroaromatic silene monomer to the siloxane segment monomer is 1:3; and the catalyst includes at least one of cerium heteropoly phosphotungstate, dichlorobis(dimethylamino)silane zirconium complex, and lanthanum trifluoromethanesulfonate.

[0019] Azaaromatic silicene monomers contain conjugated aromatic heterocycles and Si=NH bonds, exhibiting high thermal stability and good polarity. The aromatic heterocycles provide π-electron delocalization, enhancing the thermal stability and dielectric polarization capability of the material. The Si=NH groups react with siloxane segments to form silicon-nitrogen (Si-N) bonds, enhancing the high-temperature resistance and chemical inertness of the composite material. As rigid segments, they can effectively improve the material's modulus and dielectric constant. The flexible backbone Si-O-Si structure allows for the introduction of functional groups such as aminopropyl, phenylethyl, and fluorosilicone at the end. The Si-O-Si segments impart excellent flexibility and low-temperature toughness to the material. Aminopropyl and phenylethyl end groups enhance interfacial compatibility and organic phase affinity. Fluorosilicone groups provide low surface energy and hydrophobicity, while also improving electrical insulation and dielectric loss control. The catalyst composed of cerium heteropolyphosphotungstate, dichlorobis(dimethylamino)silane zirconium complex, and lanthanum trifluoromethanesulfonate has strong acid catalysis and Lewis acid active sites, promoting Si-N and Si-O cross-linking reactions, achieving high-efficiency condensation at low temperatures, improving reaction selectivity, avoiding the formation of by-products, and enhancing the density and thermal stability of the cross-linked network.

[0020] Step S1 includes: Dissolve cyanuric chloride in anhydrous toluene, stir and cool to 0°C, add a mixture of 3-aminophenyltrichlorosilane and anhydrous pyridine dropwise at a rate of 1 mL / min, heat to 70°C after the addition is complete, and reflux for 12 hours to obtain a nitrogen-aromatic ring-silicon chloride precursor.

[0021] Cyanuric chloride is a strong electrophile with a reactive Cl atom, readily undergoing nucleophilic substitution reactions with amino-containing organosilicon monomers. The -NH2 group on 3-aminophenyltrichlorosilane acts as a nucleophile to attack the electrophilic carbon of cyanuric chloride (the C-Cl site on the ring), forming a nitrogen-heteroaromatic ring-silicon-chloride precursor. Anhydrous pyridine acts as a proton acceptor (buffer base) in this process, absorbing the HCl byproduct produced during the reaction and preventing side reactions such as polymerization. This forms a stable nitrogen-heteroaromatic ring structure and introduces a π-conjugated system, imparting high thermal stability and dielectric polarization to the subsequent material. This generates silicon-chloride active sites (Si-Cl), providing reactive groups for subsequent condensation reactions with siloxane segments. Precisely controlled droplet acceleration and low-temperature reaction temperatures suppress side reactions (such as the formation of cyanuric chloride cross-linking byproducts), ensuring the controllable molecular structure and purity of the product.

[0022] After the reaction is completed, the mixture is cooled to room temperature, deionized water is added and filtered, the filtered solution is rotary evaporated, and purified by column chromatography to obtain an azaarylsilene monomer.

[0023] After the addition of deionized water, unreacted cyanuric chloride is hydrolyzed, byproducts are removed, and rotary evaporation removes the solvent (toluene) and low-boiling-point small molecule impurities. Column chromatography further purifies the reaction product, separating the unreacted raw materials and byproducts to obtain high-purity azaarylsilene monomers, ensuring the selectivity and network uniformity of the subsequent condensation reaction. Removing residual small molecules and byproducts prevents side polymerization, bubble defects, or electrical property degradation during subsequent material preparation, improves the reactivity and interfacial compatibility of the azaarylsilene monomers, and ensures that the Si-Cl sites can efficiently participate in subsequent condensation and crosslinking.

[0024] In a three-necked flask, add octamethylcyclotetrasiloxane and toluene, introduce nitrogen, then add p-toluenesulfonic acid, raise the temperature to 80°C, and stir for 2 hours to generate siloxane segments.

[0025] Under the catalysis of p-toluenesulfonic acid, octamethylcyclotetrasiloxane undergoes cationic ring-opening polymerization to produce linear polydimethylsiloxane segments. The addition of toluene as a diluent helps control viscosity, inhibit overpolymerization, and ensure appropriate segment length. Post-reaction, γ-aminopropyltriethoxysilane and phenethyltriethoxysilane are added as end-capping agents to introduce polar aminopropyl and organophilic phenethyl end groups, thereby adjusting the segment functionality. This results in siloxane segments with excellent flexibility and thermo-oxidative stability. The end-capping groups (aminopropyl and phenethyl) enhance chemical affinity and interfacial compatibility with the azaarylsilene monomer, forming the segment foundation for subsequent organic-inorganic synergistic crosslinking, imparting excellent flexibility, elasticity, and dielectric properties to the composite. Controlling the degree of polymerization balances segment flexibility with material strength, avoiding the degradation of mechanical properties caused by excessive segment length.

[0026] γ-Aminopropyltriethoxysilane and phenethyltriethoxysilane are added dropwise to the siloxane segment and the reaction is continued for 4 hours. After the reaction is completed, a neutralization catalyst is added and rotary evaporation is performed to obtain a siloxane segment monomer, wherein the neutralization catalyst includes at least one of anhydrous triethylamine, anhydrous sodium bicarbonate, and aniline.

[0027] γ-Aminopropyltriethoxysilane contains an aminopropyl group (—NH2) at its end, which is polar and reactive. Triethoxysilane can condense with the active sites at the end of the siloxane backbone to achieve endcapping. The aminopropyl group enhances interfacial reactivity and polar compatibility with subsequent nitrogen heteroaromatic silicene monomers. Phenethyltriethoxysilane, with a phenethyl group (—CH2CH2Ph) at its end, provides hydrophobicity and organic phase compatibility. Triethoxysilane also achieves endcapping through condensation. The phenethyl group enhances the composite's interfacial wettability and compatibility with organic phases.

[0028] Cationic polymerization systems catalyzed by p-toluenesulfonic acid are slightly acidic. Neutralizing catalysts are used to neutralize residual acidity, preventing secondary crosslinking or acidic degradation in subsequent reactions and improving the storage stability of the siloxane segment monomers. They also remove low-boiling-point solvents (such as toluene and alcohols) and unreacted small molecules to ensure monomer purity and reactivity.

[0029] S1.1. Degas the nitrogen heteroaromatic silicene monomer and the siloxane segment monomer at 120° C. in vacuum for 1 hour, and premix the nitrogen heteroaromatic silicene monomer and the siloxane segment monomer at room temperature for 30 minutes using ultrasonic dispersion and magnetic stirring to obtain a premix.

[0030] Degassing removes dissolved oxygen and trace moisture from the monomers, preventing bubbles and side reactions during the reaction. Ultrasonic dispersion and magnetic stirring ensure uniform dispersion of the nitrogen heteroarylsilene and siloxane segments at the nanoscale, forming a stable precursor system. This improves the uniformity and rate of the monomer reaction and prevents localized agglomeration and phase separation in subsequent reactions.

[0031] S1.2. Transfer the premixture into the reactor and continue to introduce nitrogen. The outlet of nitrogen is connected to the alkaline absorption liquid. The flow rate of nitrogen is 100-200 mL / min. Set the heating rate to 5°C / min. When the temperature reaches 150-180°C, adjust the flow rate of nitrogen to 50-100 mL / min. Keep the temperature and react for 3-6 hours while stirring at 200 rpm. The alkaline absorption liquid includes at least one of sodium hydroxide solution, sodium carbonate solution, and ammonia solution. Nitrogen shielding isolates O2 and H2O from the air, preventing oxidation or hydroxylation of the siloxane segments. Nitrogen flow control: A high flow rate (100-200 mL / min) during the initial reaction accelerates devolatilization. After the reaction temperature stabilizes, the flow rate is reduced (50-100 mL / min) to control the reaction rate. A slow heating rate of 5°C / min helps control the uniformity of the condensation reaction and interfacial reactivity, preventing gelation caused by sudden cross-linking. This ensures controllable reactivity of the reaction system, promotes uniform backbone formation and cross-linking, prevents local overheating and curing, and improves the material's density and dielectric uniformity.

[0032] In one example, pentafluorophenylborane is first dissolved in 10 mL of anhydrous acetonitrile and stirred to form a 0.05-0.1 mol / L pentafluorophenylborane solution. When the temperature reaches 150-180°C, the pentafluorophenylborane solution is added. Unlike conventional catalysts, B(C6F5)3 does not directly participate in Si-N or Si-O polycondensation. Instead, it enhances the polarizability of the aromatic silicene monomer through "electron cloud shifting." This electronic reconstruction effect can induce a more uniform networked polycondensation sequence, optimizing the synergy between dielectric and mechanical properties at the molecular level.

[0033] S1.3. Detect the viscosity of the premixture in real time. When the real-time viscosity of the premixture rises to twice the initial viscosity of the premixture, stop stirring and heating.

[0034] Real-time viscosity monitoring uses changes in system viscosity as a feedback parameter for crosslinking and molecular weight growth. The reaction is terminated when the viscosity reaches twice the initial viscosity. This 2x viscosity is an empirical value determined through repeated testing. It balances molecular weight growth, network formation, and system fluidity, preventing brittleness caused by excessive crosslinking and stress concentration caused by excessive crosslinking density. Dynamic control of the reaction endpoint ensures the processability and subsequent molding properties of the elastic prepolymer. Viscosity feedback enables precise control of molecular chain length, crosslinking, flexibility, and dielectric properties.

[0035] S1.4. Cool the mixture to 80°C, stop introducing nitrogen and slowly release it, add a capping agent and perform rotary evaporation to obtain an elastic prepolymer.

[0036] Cooling to 80°C reduces reaction activity and prevents uncontrolled chain growth during subsequent operations. Adding a capping agent blocks residual active functional groups to prevent secondary crosslinking or degradation during storage. Rotary evaporation removes low-boiling-point solvents and unreacted small molecules, improving product purity and performance stability. Termination of the reaction deactivates the end groups of the chain segments, improving storage stability and subsequent composite processing performance, removing impurities, and enhancing the dielectric uniformity and heat resistance of the composite material.

[0037] S2. preparing boron-functionalized zirconium titanium nitride nanosheets by plasma stripping, surface treating the boron-functionalized zirconium titanium nitride nanosheets, introducing fluorine-boron functional groups, and obtaining superlattice phase change nanosheets; Step S2 includes: S2.1. Place the zirconium titanium nitride substrate in a plasma reaction chamber, introduce an argon-nitrogen mixed gas, excite the plasma, and then introduce boron gas. The reaction time is 2 to 4 hours. After the reaction is completed, boron-functionalized zirconium titanium nitride nanosheets are obtained. The plasma power is 180 to 220 W, and the reaction temperature is 220 to 240 °C.

[0038] Argon is an inert gas that primarily provides a plasma excitation environment. Nitrogen, under plasma excitation, generates reactive nitrogen species (N•, N2⁺), which reconstruct unsaturated bonds or defect sites on the substrate surface, enhancing surface reactivity and bonding. Boron trifluoride (BF3) has strong Lewis acidity and can interact with sites with high electron cloud density on the nitride surface (such as Ti-N bonds), promoting the formation of boron-nitrogen (BN) bonds. Diborane (B2H6), a highly reducing boron source, embeds boron into the surface or lattice defects through a reduction-adsorption mechanism, forming a boron-doped zirconium titanium nitride layer. If the substrate is aluminum-doped zirconium titanium nitride, the aluminum atoms can serve as structural control units, assisting in the formation of layered nanosheet structures, enhancing conductivity and interlayer delocalized electronic behavior. Chemical bonds such as BN and B-Ti are introduced on the surface of the zirconium-titanium nitride substrate to achieve boron functionalization, improve the material's interfacial activity and chemical stability, charge distribution uniformity, inhibit electron-hole recombination, and increase mechanical strength and thermal stability (the binding energy of boron-nitrogen bonds and boron-titanium bonds is high), forming a two-dimensional layered boron-functionalized nanosheet structure, providing the morphology and lattice basis for the subsequent construction of superlattices.

[0039] S2.2. Place the boron-functionalized zirconium titanium nitride nanosheets in a quartz boat in a tube furnace, heat to 250°C, pretreat in an argon atmosphere for 30 minutes, raise the temperature to 300°C, introduce fluorine gas and react with aminoborane for 1 hour to obtain superlattice phase change nanosheets.

[0040] Pretreatment removes residual gases and weakly bonded compounds from the surface, inducing ordering of surface defects and providing active sites for the subsequent fluorine-boron synergistic reaction. Boron trifluoride (BF3) exhibits strong Lewis acidity during the fluorination reaction, complexing with surface metal-nitrogen bonds or uncoordinated metal atoms to form stable MF (Ti-F, Zr-F) bonds, enhancing interfacial electronegativity. Hexafluoroethane and carbon tetrafluoride decompose at high temperatures to generate fluorine radicals (F•) and carbon-fluorine radical fragments (CFx•, where x is 1-3), which further modify the surface and form a fluorinated layer, improving corrosion resistance and interfacial charge control capabilities. Aminoborane decomposes to generate active boron radical (B•) and nitrogen radical (N•) species, which assist in the formation of boron-nitrogen and boron-metal bonds, enhance interlayer coupling, provide electron-rich amino functional sites, and optimize the material's polarization behavior and interfacial charge distribution. Fluorine-boron synergistic doping introduces multiple chemical bonds, including MF, BN, and BM, on the material surface, enhancing superlattice order, regulating lattice distortion, stabilizing interlayer spacing, and achieving superlattice phase transition characteristics. Polar MF bonds enhance the interfacial electric field effect, promoting electron transport and ion screening. The flexible regulation of boron and the strong polarization effect of fluorine synergize to achieve precise control of phase transition temperature, specific heat capacity, and thermal conductivity. The shielding effect of the fluorinated layer extends the material's service life in strong acidic, alkaline, and high-temperature environments.

[0041] The zirconium titanium nitride substrate includes at least one of a zirconium titanium nitride solid solution, a zirconium titanium aluminum nitride composite, and a zirconium titanium boron nitride composite; the boron-functionalized zirconium titanium nitride nanosheets include at least one of a zirconium titanium nitride-doped fluoroborene nanosheet, an aluminum-doped fluoroborene layered zirconium titanium nitride nanosheet, and a boron-doped zirconium titanium nitride nanosheet; the flow ratio of argon:nitrogen:boride gas is (75-80):(15-20):5; the boride gas includes at least one of boron trifluoride and diborane; and the fluoride gas includes at least one of boron trifluoride, hexafluoroethane, and carbon tetrafluoride.

[0042] S3. Ultrasonicate the superlattice phase change nanosheets and the bifunctional fluorosilicon phosphoramide interface regulator in anhydrous acetonitrile for 30 minutes to obtain a suspension, add the suspension to the elastic prepolymer, stir at 60°C for 2 hours to form a composite slurry, and thermally cure the composite slurry to obtain a high-temperature resistant and high-dielectric silicone composite material.

[0043] Step S3 includes: 0.1 mol of diphenylphosphoryl chloride was dissolved in 200 mL of acetonitrile and cooled to 0°C. A mixture of 0.1 mol of trifluoropropyltriethoxysilane and 0.12 mol of anhydrous pyridine was added dropwise at a drop rate of 1 mL / min. The reaction temperature was raised to 40°C and stirred for 6 hours. After stirring, the mixture was filtered and rotary evaporated, and then purified by silica gel column chromatography to obtain a bifunctional fluorosilicylphosphoramide interface regulator. The silica gel column was filled with petroleum ether and ethyl acetate, and the mass ratio of petroleum ether to ethyl acetate was 4:1.

[0044] Diphenylphosphoryl chloride reacts with trifluoropropyltriethoxysilane in a nucleophilic substitution reaction. Pyridine acts as an alkaline acid scavenger to absorb the HCl byproduct generated during the reaction, promoting the smooth progress of the reaction. This results in an interfacial modulator with bifunctional properties: a phosphoramide group (P=ON) and a trifluoropropylsilane group. The target product is further purified by silica gel column chromatography (petroleum ether / ethyl acetate 4:1) to remove unreacted starting materials and byproducts. The phosphoramide group exhibits excellent polarity and electron-donating properties, forming hydrogen bonds / coordination bonds with nitrogen and metal atoms on the nanosheet surface, enhancing interfacial bonding strength. The trifluoropropylsilane group provides hydrophobicity and low dielectric loss, while also being chemically compatible with the siloxane segments. This bifunctional structure achieves interfacial coupling and synergistic matching between the inorganic nanosheets and the organic silica matrix.

[0045] S3.1. Superlattice phase change nanosheets and a bifunctional fluorosilicon-phosphoramide interface modulator were added to acetonitrile and dispersed using intermittent ultrasonic pulses (5 minutes on, 1 minute off) to obtain a coating suspension. The mass ratio of superlattice phase change nanosheets to bifunctional fluorosilicon-phosphoramide interface modulator was (1-2):10. Intermittent ultrasonic pulses (5 minutes on, 1 minute off) achieved efficient dispersion and surface activation of the nanosheets, preventing agglomeration. The fluorosilicon-phosphoramide interface modulator bound to the BN and Ti-N bonds on the nanosheet surface via polar phosphoramide groups, with trifluoropropyl chains extending outward to form a core-shell coating structure. The mass ratio of (1-2):10 ensured sufficient coating of the interface agent while also exposing the effective reactive surface of the nanosheets. This enhanced the dispersion stability and interfacial bonding strength of the superlattice phase change nanosheets in the organosilicon matrix. This reduced interfacial energy, alleviated stress concentration, and improved the mechanical toughness and interfacial electrical uniformity of the composite. This enhanced interfacial polarization of the inorganic-organic phase helped improve the dielectric constant of the composite.

[0046] S3.2. Add the coating suspension dropwise to the elastic prepolymer preheated to 60°C at a rate of 1 mL / min. Stir continuously for 2 hours at a stirring speed of 300 rpm to obtain a composite slurry.

[0047] The coated suspension was added dropwise to a 60°C elastic prepolymer, stirring at a low speed (300 rpm) to uniformly embed the nanosheets into the siloxane network. Stirring at a low temperature (60°C) ensured controlled viscosity and avoided localized gelation or agglomeration due to rapid reactions. This achieved uniform dispersion of the superlattice nanosheets within the siloxane matrix and their integration into a three-dimensional network. This resulted in a three-phase composite structure of flexible siloxane segments, rigid superlattice nanosheets, and interface modifier. This optimized the interfacial polarization response, enhancing the material's dielectric properties, flexibility, and dimensional stability.

[0048] S3.3. Place the composite slurry in a gradient temperature difference mold with an upper mold temperature of 350°C and a lower mold temperature of 250°C. Adjust the internal pressure to 20 MPa and maintain for 30 minutes. Cool to room temperature and then demould to obtain a composite material blank.

[0049] A temperature gradient is created between the upper mold at 350°C and the lower mold at 250°C, driving the orderly orientation of the molecular segments and fillers within the material. A pressure of 20 MPa promotes the densification of the composite slurry and the orientation of the inorganic fillers. A 30-minute hot press curing ensures the complete cross-linking reaction and the formation of a stable three-dimensional network structure. After cooling to room temperature, the mold is demolded to obtain a dense composite material blank. Under the induction of the gradient temperature difference, the nanosheets undergo layered and orderly orientation, improving the in-plane dielectric properties and thermal conductivity. High pressure promotes interfacial bonding and structural densification, improving the mechanical strength and heat resistance of the material. This ensures low dielectric loss and high capacitance stability for the entire composite material.

[0050] In one embodiment, during step S3.3, a gradient temperature mold is provided with upper and lower electrodes and a DC bias voltage is applied with a peak voltage of 500V to maintain constant temperatures and internal pressure. This electric field induces the nanosheets to migrate in orientation, forming a gradient structure from high to low polarization density. This not only achieves physical hot pressing but also electric field-assisted gradient dielectric control.

[0051] To accurately determine the applied voltage, the electric field strength must not only overcome the viscous resistance of the medium in which the nanosheets are located, but also the interaction between the thermal gradient, the nanosheet concentration gradient, and the polarization response of the prepolymer. The following equation is proposed: is the actual voltage applied at the tth second during the hot pressing process (unit V), is the target peak voltage (500 V in this embodiment). is the temperature of the material at time t The equivalent viscosity (Pa·s) under the condition of MgSO4 is measured by a viscometer. is the instantaneous orientation index of the superlattice phase change nanosheet in unit volume, expressed as a normalized function from 0 to 1, initially 0, and gradually increases with the increase of electric field and time. is the proportional control factor (setting range 0.1~1.5), which represents the electric field induced efficiency; and are the amplitude and angular frequency of the small oscillation voltage respectively ( =20~30V, =0.2~1.5rad / s), which is used to simulate the material response hysteresis and local interface polarization disturbance. The main term is the exponential rise term, which simulates the gradual effectiveness of the electric field after overcoming the viscosity resistance and the migration inertia of the superlattice phase change nanosheet; while the correction term is the periodic fluctuation term, which is used to deal with the microscopic oscillation and local orientation reconstruction during the response of the superlattice phase change nanosheet. By setting different 、 、 Parameters can achieve personalized voltage response matching for different thicknesses and different prepolymer concentration systems. In actual applications, the power control system embeds a PID-coupling control algorithm and monitors the temperature inside the mold based on the feedback. , online viscosity measurement or preset model function, dynamic calculation of voltage output The nanosheets were then induced to form an oriented aggregation state along the electric field in the thickness direction of the mold and permanently fixed under the high temperature and high pressure curing environment, thus constructing a composite microstructure with a continuous dielectric gradient.

[0052] In the preparation process of the high temperature resistant high dielectric silicone composite material of the present invention, the voltage control equation adopted not only provides an electric field application path, but also constructs an electric-thermal-rheological coupling control mechanism based on the adaptive response of the material physical state. , and the nanosheet orientation response exponent ϕ(t) dynamically adjust the actual voltage applied between the electrodes in the gradient temperature mold. As the hot pressing reaction proceeds, the material temperature rises and the system viscosity decreases significantly. However, the voltage does not increase linearly or remain constant. Instead, it follows an exponential growth logic, rapidly increasing within the window where the material transitions from a "semi-solid" state to a "flowable" state. This precisely drives the superlattice phase-change nanosheets to migrate and align along the electric field during the period of lowest viscosity and most reconfigurable structure. This dynamic voltage response mechanism avoids the problems of sheet agglomeration and localized electrical breakdown that can occur with traditional constant-voltage methods.

[0053] In addition, a small oscillation term is added to the control equation , simulating the interface polarization perturbations and charge density fluctuations during the nanoscale structural reconstruction process, effectively improving the hierarchical coherence and polarization direction uniformity of the nanosheet arrangement, so that a continuous and controllable dielectric gradient structure is formed in the z-axis direction. This multi-stage, progressive electric field induction strategy, combined with the temperature-controlled curing and viscosity adjustment mechanism, jointly promotes the transformation process of the internal structure of the material from disorder-rearrangement-fixation. Therefore, the voltage control equation is not only the electric field application curve in the preparation process, but also undertakes the key process driving function of the internal structure construction, orientation regulation, and gradient formation of the composite material. It is the core technical link to achieve the high dielectric properties, directional polarization response capability and high-frequency stability of the material of the present invention. Compared with traditional uniform hot pressing or single voltage curing technology, this scheme has realized the dynamic electric field coupled thermally induced dielectric structure construction path in the silicone-based composite system for the first time, which has significant innovation and practical value.

[0054] S3.4. Place the composite material blank in a radio frequency plasma reactor, introduce a nitrogen-fluorine mixed gas, the plasma power is 300 W, and the reaction time is 10 minutes to obtain a high-temperature resistant and high-dielectric silicone composite material, wherein the nitrogen-fluorine mixed gas includes nitrogen and carbon tetrafluoride, and the flow ratio of nitrogen:carbon tetrafluoride is 3:1.

[0055] Under plasma excitation, a nitrogen-fluorine gas mixture (N2 / CF4 = 3:1) generates F•, CFx•, and N• active species. F• reacts with active sites on the material surface, forming M-F and Si-F bonds, enhancing surface hydrophobicity and dielectric insulation. N• species modify surface defects, forming a thin network of N-Si and N-B bonds, enhancing interfacial chemical stability. A fluorinated protective layer forms on the surface, improving the composite's corrosion resistance, aging resistance, and resistance to moisture and heat. This reduces surface dielectric loss, enhances dielectric breakdown strength and insulation properties, and modulating surface polarity helps improve compatibility and long-term reliability between the material and the electrode and packaging interfaces.

[0056] The present invention provides a high-temperature resistant high-dielectric silicone composite material, which is made by a preparation method of the high-temperature resistant high-dielectric silicone composite material. The high-temperature resistant high-dielectric silicone composite material includes an elastic prepolymer and a superlattice phase change nanosheet; wherein, Elastic prepolymer is used as the main skeleton of high-temperature resistant and high-dielectric silicone composite materials; Superlattice phase change nanosheets are used to improve the dielectric constant of high-temperature resistant and high-dielectric silicone composite materials.

[0057] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a high temperature resistant and high dielectric silicone composite material, characterized in that the steps include: S1. Under an inert atmosphere, a nitrogen heteroaromatic silene monomer and a siloxane segment monomer are mixed in a molar ratio, a catalyst is added, and the mixture is reacted at 150-180° C. for 3-6 hours to prepare an elastic prepolymer; S2. preparing boron-functionalized zirconium titanium nitride nanosheets by plasma stripping, surface treating the boron-functionalized zirconium titanium nitride nanosheets, introducing fluorine-boron functional groups, and obtaining superlattice phase change nanosheets; S3. Ultrasonicate the superlattice phase change nanosheets and the bifunctional fluorosilicon phosphoramide interface regulator in anhydrous acetonitrile for 30 minutes to obtain a suspension, add the suspension to the elastic prepolymer, stir at 60°C for 2 hours to form a composite slurry, and thermally cure the composite slurry to obtain a high-temperature resistant and high-dielectric silicone composite material.

2. The method for preparing a high-temperature resistant and high-dielectric silicone composite material according to claim 1, characterized in that: In step S1, the nitrogen heteroaromatic silene monomer includes at least one of 3,6-diamino-1,2,4-triazacyclosilene, 2-(aminophenyl)-tetraazasilicon-fused cycloene, and bis(3-aminopyridyl)silene; the siloxane segment monomer includes at least one of aminopropyl-terminated polydimethylsiloxane, phenylethyl-terminated polyphenylsiloxane, and diaminoethyl-terminated polymethylfluorosiloxane; the molar ratio of the nitrogen heteroaromatic silene monomer to the siloxane segment monomer is 1:3; and the catalyst includes at least one of cerium heteropoly phosphotungstate, dichlorobis(dimethylamino)silane zirconium complex, and lanthanum trifluoromethanesulfonate.

3. The method for preparing a high-temperature resistant and high-dielectric silicone composite material according to claim 1 or 2, characterized in that: Step S1 includes: S1.

1. Degas the nitrogen heteroarylsilene monomer and the siloxane segment monomer separately at 120° C. under vacuum for 1 hour, and premix the nitrogen heteroarylsilene monomer and the siloxane segment monomer at room temperature for 30 minutes using ultrasonic dispersion and magnetic stirring to obtain a premix; S1.

2. Transfer the premix into the reactor and continue to introduce nitrogen gas, with the outlet of the nitrogen connected to the alkaline absorption liquid. The nitrogen flow rate is 100-200 mL / min. Set the heating rate to 5°C / min. When the temperature reaches 150-180°C, adjust the nitrogen flow rate to 50-100 mL / min. Keep the reaction warm for 3-6 hours while stirring at 200 rpm. S1.

3. Real-time monitoring of the viscosity of the premixture. When the real-time viscosity of the premixture rises to twice the initial viscosity of the premixture, stirring and heating are stopped. S1.

4. Cool the mixture to 80°C, stop introducing nitrogen and slowly release it, add a capping agent and perform rotary evaporation to obtain an elastic prepolymer.

4. The method for preparing a high-temperature resistant and high-dielectric silicone composite material according to claim 3, characterized in that: Before step S1.1, the following steps are also included: Dissolve cyanuric chloride in anhydrous toluene, stir and cool to 0°C, add a mixture of 3-aminophenyltrichlorosilane and anhydrous pyridine dropwise at a rate of 1 mL / min, heat to 70°C after the addition is complete, and reflux for 12 hours to obtain an azoaromatic ring-silicon chloride precursor; After the reaction is completed, the mixture is cooled to room temperature, deionized water is added and filtered, the filtered solution is rotary evaporated, and purified by column chromatography to obtain an azaarylsilene monomer; In a three-necked flask, add octamethylcyclotetrasiloxane and toluene, introduce nitrogen, then add p-toluenesulfonic acid, raise the temperature to 80°C, and stir for 2 hours to generate siloxane segments; γ-Aminopropyltriethoxysilane and phenethyltriethoxysilane are added dropwise to the siloxane segment and the reaction is continued for 4 hours. After the reaction is completed, a neutralization catalyst is added and rotary evaporation is performed to obtain a siloxane segment monomer, wherein the neutralization catalyst includes at least one of anhydrous triethylamine, anhydrous sodium bicarbonate, and aniline.

5. The method for preparing a high-temperature resistant and high-dielectric silicone composite material according to claim 1, characterized in that: Step S2 includes: S2.

1. Placing a zirconium titanium nitride substrate in a plasma reaction chamber, introducing an argon-nitrogen mixed gas, exciting the plasma, and then introducing boronization gas. The reaction time is 2-4 hours, and after the reaction is completed, boron-functionalized zirconium titanium nitride nanosheets are obtained. The plasma power is 180-220 W, and the reaction temperature is 220-240°C. S2.

2. Place the boron-functionalized zirconium titanium nitride nanosheets in a quartz boat in a tube furnace, heat to 250°C, pretreat in an argon atmosphere for 30 minutes, raise the temperature to 300°C, introduce fluorine gas and react with aminoborane for 1 hour to obtain superlattice phase change nanosheets.

6. The method for preparing a high-temperature resistant and high-dielectric silicone composite material according to claim 5, characterized in that: In step S2, the zirconium titanium nitride substrate includes at least one of a zirconium titanium nitride solid solution, a zirconium titanium aluminum nitride composite, and a zirconium titanium boron nitride composite; the boron-functionalized zirconium titanium nitride nanosheets include at least one of a zirconium titanium nitride-doped fluoroborene nanosheets, an aluminum-doped fluoroborene layered zirconium titanium nitride nanosheets, and a boron-doped zirconium titanium nitride nanosheets; the flow ratio of argon:nitrogen:boride gas is (75-80):(15-20):5; the boride gas includes at least one of boron trifluoride and diborane; and the fluoride gas includes at least one of boron trifluoride, hexafluoroethane, and carbon tetrafluoride.

7. The method for preparing a high-temperature resistant and high-dielectric silicone composite material according to claim 1, characterized in that: Step S3 includes: S3.

1. Adding superlattice phase change nanosheets and a bifunctional fluorosilicic acid phosphoramide interface modulator to acetonitrile and dispersing the superlattice phase change nanosheets with a 1-minute pause for every 5 minutes to obtain a coating suspension, wherein the mass ratio of superlattice phase change nanosheets to bifunctional fluorosilicic acid phosphoramide interface modulator is (1-2):10; S3.

2. Add the coating suspension dropwise to the elastic prepolymer preheated to 60°C at a rate of 1 mL / min. Stir continuously for 2 hours at a stirring speed of 300 rpm to obtain a composite slurry. S3.

3. Place the composite slurry in a gradient temperature mold with an upper mold temperature of 350°C and a lower mold temperature of 250°C. Adjust the internal pressure to 20 MPa and maintain for 30 minutes. Cool to room temperature and then demould to obtain a composite body. S3.

4. Place the composite material blank in a radio frequency plasma reactor, introduce a nitrogen-fluorine mixed gas, the plasma power is 300 W, and the reaction time is 10 minutes to obtain a high-temperature resistant and high-dielectric silicone composite material, wherein the nitrogen-fluorine mixed gas includes nitrogen and carbon tetrafluoride, and the flow ratio of nitrogen:carbon tetrafluoride is 3:

1.

8. The method for preparing a high-temperature resistant and high-dielectric silicone composite material according to claim 7, characterized in that: Before step S3.1, step S3 further includes: 0.1 mol of diphenylphosphoryl chloride was dissolved in 200 mL of acetonitrile and cooled to 0°C. A mixture of 0.1 mol of trifluoropropyltriethoxysilane and 0.12 mol of anhydrous pyridine was added dropwise at a drop rate of 1 mL / min. The reaction temperature was raised to 40°C and stirred for 6 hours. After stirring, the mixture was filtered and rotary evaporated, and then purified by silica gel column chromatography to obtain a bifunctional fluorosilicylphosphoramide interface regulator. The silica gel column was filled with petroleum ether and ethyl acetate, and the mass ratio of petroleum ether to ethyl acetate was 4:

1.

9. A high temperature resistant and high dielectric silicone composite material, characterized in that: The high-temperature resistant and high-dielectric silicone composite material is prepared by the preparation method of any one of claims 1 to 9, wherein the high-temperature resistant and high-dielectric silicone composite material comprises an elastic prepolymer and a superlattice phase change nanosheet; wherein, The elastic prepolymer is used as the main skeleton of the high-temperature resistant and high-dielectric silicone composite material; The superlattice phase change nanosheet is used to improve the dielectric constant of the high-temperature resistant and high-dielectric silicone composite material.

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