Insulating wave-absorbing liquid silica gel material and preparation method thereof

Abstract

This invention relates to an insulating and microwave-absorbing liquid silicone material and its preparation method, belonging to the field of shielding materials technology. The liquid silicone material comprises: 38-45 wt% carbonyl iron powder, 5.5-7.2 wt% fluorinated modified silicone oil, 5-8 parts reactive diluent, 0.2-0.3 parts defoamer, and 0.1-0.15 parts leveling agent, with the balance being liquid silicone rubber base. The fluorinated modified silicone oil is prepared by a substitution reaction between tetraethylenepentamine and allyl chloride to obtain intermediate 1, followed by hydrosilylation with hydrogen-containing silicone oil to obtain intermediate 2, and finally by a substitution reaction with trifluoroiodopropane to introduce a fluorine structure. The polyamine in the molecule chelates with the carbonyl iron powder through a multidentate chelation effect, forming a dense organosilicon insulating layer on the iron powder surface, increasing the volume resistivity. Simultaneously, the fluorine structure reduces the surface energy of the filler, improves dispersibility and filling fluidity, and reduces the system viscosity. Furthermore, by optimizing impedance matching and enhancing interfacial polarization loss, the microwave absorption performance is significantly improved.

Description

Technical Field

[0001] This invention belongs to the field of shielding materials technology, specifically relating to an insulating and absorbing liquid silicone material and its preparation method. Background Technology

[0002] Electromagnetic absorbing materials are functional materials that can convert the energy of incident electromagnetic waves into heat or other forms of energy and effectively attenuate them, thereby reducing electromagnetic wave reflections. With the increasing demands for electromagnetic compatibility in fields such as communication equipment, automotive electronics, and aerospace, the strategic value of electromagnetic absorbing materials in suppressing electromagnetic interference, ensuring stable signal transmission, and achieving stealth capabilities for military equipment is becoming increasingly prominent.

[0003] Based on different loss mechanisms, microwave absorbing materials can be mainly divided into two categories: dielectric loss type and magnetic loss type. Dielectric loss type microwave absorbing materials are represented by carbon-based materials such as carbon black, graphene, and carbon nanotubes, which mainly rely on the high dielectric loss characteristics of carbon materials to convert electromagnetic energy into Joule heat dissipation. Magnetic loss type microwave absorbing materials are represented by ferrites, carbonyl iron powder, and magnetic metal nanomaterials, which mainly achieve electromagnetic wave absorption through mechanisms such as magnetic domain wall resonance and natural resonance. Among them, carbonyl iron powder has attracted widespread attention due to its high saturation magnetization, high Curie temperature, and wide absorption bandwidth. However, the above-mentioned microwave absorbing materials mostly exist in powder form, which is difficult to directly mold into the required device shape. They usually need to be composited with a polymer matrix to obtain good molding ability and mechanical properties.

[0004] Among numerous polymer matrices, liquid silicone rubber stands out as an ideal matrix material for microwave absorbing materials due to its excellent insulation, resistance to high and low temperatures, weather resistance, and chemical stability. Liquid silicone rubber is an addition-type room-temperature vulcanizing silicone rubber. Its crosslinking process generates no byproducts, has low molding shrinkage, and excellent flowability, making it suitable for molding and potting processes. Therefore, it is widely used in seals, gaskets, and protective coatings in aerospace, automotive electronics, and consumer electronics. Organosilicon-based microwave absorbing materials, with their superior electrical and physical properties, can be applied to military electronic equipment in aviation, aerospace, and shipbuilding, as well as data communication equipment.

[0005] However, existing technologies for preparing microwave absorbing materials using liquid silica gel and carbonyl iron powder face the following technical challenges: First, the contradiction between absorption and insulation performance. To achieve effective electromagnetic wave absorption, a high content of magnetic absorbing filler needs to be added to the silica gel matrix. A large amount of highly conductive carbonyl iron powder forms a conductive network within the matrix, leading to a significant decrease in the material's volume resistivity and deterioration of its insulation performance. Under high-frequency electromagnetic fields, this conductive network can also induce significant eddy current losses, further degrading magnetic loss performance. Second, the contradiction between high filler content and processing performance. When the amount of carbonyl iron powder added exceeds a certain threshold, the viscosity of the composite material system increases sharply, and its fluidity decreases significantly. On the one hand, this makes it difficult for the material to fill the fine structures and complex cavities of the mold, affecting molding accuracy; on the other hand, it is difficult to completely remove air bubbles during the degassing process, resulting in residual pores inside the material, which in turn affects the uniformity of electromagnetic wave absorption and the reliability of mechanical properties. Liquid silica gel itself has good filling capacity, but the introduction of a large amount of inorganic filler greatly weakens this advantage.

[0006] In summary, how to achieve high microwave absorption performance with high filler content while maintaining the good insulation and filling capacity of liquid silicone materials has become a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0007] In order to solve the technical problems mentioned in the background art, the purpose of this invention is to provide an insulating and microwave absorbing liquid silicone material and its preparation method.

[0008] The objective of this invention can be achieved through the following technical solutions: An insulating and microwave-absorbing liquid silicone material, specifically composed of: 38-45 wt% carbonyl iron powder, 5.5-7.2 wt% fluorinated modified silicone oil, 5-8 parts reactive diluent, 0.2-0.3 parts defoamer, and 0.1-0.15 parts leveling agent, with the balance being liquid silicone rubber base adhesive.

[0009] The fluorinated modified silicone oil is prepared by the following method: Step A1: Under nitrogen protection, tetraethylenepentamine, triethylamine and anhydrous tetrahydrofuran were premixed, and allyl chloride was slowly added at room temperature. Then, the temperature was controlled at 40±2℃ and refluxed for 3-3.5h. After the reaction was completed, the mixture was filtered and the tetrahydrofuran was recovered by rotary evaporation to obtain intermediate 1. Furthermore, the ratio of tetraethylenepentamine, allyl chloride, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 0.2 mol: 15-20 mL: 120-180 mL. Allyl chloride undergoes a substitution reaction with the active primary amine of tetraethylenepentamine to introduce a terminal allyl group structure.

[0010] Step A2: Premix intermediate 1, hydrogen-containing silicone oil and ethylene glycol dimethyl ether, then add platinum catalyst and mix well. Under nitrogen protection, heat to 80±5℃ and reflux for 5-7 hours. After the reaction is completed, reduce pressure and rotary evaporate to recover ethylene glycol dimethyl ether to obtain intermediate 2. Furthermore, the hydrosilicon content of the hydrogen-containing silicone oil, the ratio of intermediate 1 to ethylene glycol dimethyl ether is 0.1 mol: 40-45 mmol: 200-300 mL, the platinum content of the platinum catalyst is 40-60 ppm of the total amount of hydrogen-containing silicone oil and intermediate 1, and the terminal allyl group of intermediate 1 undergoes hydrosilylation with the hydrogen-containing silicone oil to form a block-modified organosilicon compound of intermediate 1.

[0011] Furthermore, the hydrogen-containing silicone oil is a hydrogen-terminated silicone oil, which forms a linear structure through addition, resulting in better compatibility with silicone systems.

[0012] Furthermore, the average molecular weight of the hydrogen-containing silicone oil is not higher than 1000. The hydrogen-containing silicone oil with a lower molecular weight has good addition activity, and the amount of functional block of intermediate 1 at a unit dosage is relatively high, which makes it easy to form an interaction with carbonyl iron powder.

[0013] Step A3: Premix intermediate 2, trifluoroiodopropane and dioxane, then add 4-dimethylaminopyridine to mix, purge with nitrogen for protection, heat to 90-100℃ and reflux for 12-15h, cool to room temperature after the reaction is complete, add deionized water to wash, centrifuge to separate the aqueous phase, and then vacuum dry to obtain fluorinated modified silicone oil. Furthermore, the ratio of intermediate 2, trifluoroiodopropane, 4-dimethylaminopyridine and dioxane is 50g:20-25mmol:1.4-2g:150-200mL. Trifluoroiodopropane replaces the secondary amine structure introduced into the block chain of intermediate 2, and fluorine structure is introduced at the block node for modification.

[0014] Preferably, the carbonyl iron powder has an average particle size of 5-15 μm, which provides stable dispersion and effectively forms a wave-absorbing shielding layer.

[0015] A method for preparing an insulating and microwave-absorbing liquid silicone material specifically involves: premixing fluorinated modified silicone oil, reactive diluent, defoamer, and leveling agent, then adding carbonyl iron powder and mixing thoroughly, and finally adding liquid silicone rubber base adhesive and mixing thoroughly to obtain the insulating and microwave-absorbing liquid silicone material.

[0016] The beneficial effects of this invention are: This invention is based on a carbonyl iron powder microwave absorption system and introduces a fluorinated modified silicone oil blend into liquid silica gel. Compared with existing technologies, it has the following advantages: 1. The fluorinated modified silicone oil molecule incorporates multiple amine groups provided by tetraethylenepentamine units. These amine groups can form multidentate chelate interactions with carbonyl iron powder, firmly anchoring the fluorinated modified silicone oil molecules to the surface of the carbonyl iron powder particles. Compared to existing modification methods that rely solely on physical adsorption or single-point coupling, this anchoring effect exhibits higher interfacial bonding strength and a more stable coating effect. It constructs a dense and uniform organosilicon coating layer on the surface of the carbonyl iron powder particles, forming an effective physical isolation barrier between the particles. This significantly increases the resistance between the carbonyl iron powder particles in the system, effectively suppresses eddy current losses, and significantly improves the overall insulation performance of the composite material.

[0017] 2. In this invention, the fluorinated side chain structure introduced by the fluorinated modified silicone oil on the surface of carbonyl iron powder endows the carbonyl iron powder particles with extremely low surface energy. This low surface energy characteristic significantly reduces the interfacial tension between the carbonyl iron powder particles and the liquid silicone matrix, fundamentally improving the compatibility and dispersion uniformity of the filler in the matrix. On the other hand, these fluorinated side chains form a "molecular lubricant" structural layer on the particle surface, effectively reducing the frictional resistance and motion resistance between filler particles, resulting in better filling ability of the liquid silicone composite material, especially in precision components.

[0018] 3. This invention introduces a fluorine structure onto the surface of carbonyl iron powder by using fluorinated modified silicone oil. The fluorinated layer is essentially a low dielectric constant material, and the thin coating formed on the surface of the carbonyl iron powder particles effectively reduces the overall dielectric constant of the composite material. Since the impedance matching of the absorbing material is largely determined by its dielectric constant, a moderate reduction in the dielectric constant helps to bring the complex dielectric constant and complex permeability of the material closer together, thereby optimizing the impedance matching state at the material-air interface, reducing electromagnetic wave reflection losses on the material surface, and improving the electromagnetic wave entry efficiency and internal absorption rate. A clear heterogeneous interface is formed between the fluorinated coating layer and the carbonyl iron powder particles, and the presence of this interface significantly enhances the interface polarization effect. When electromagnetic waves pass through this interface, charge accumulates and relaxes at the interface of materials with different dielectric properties, converting electromagnetic wave energy into Joule heat, thereby increasing the dielectric loss contribution of the material. This additional dielectric loss mechanism works synergistically with the intrinsic magnetic loss mechanism of carbonyl iron powder, resulting in a systematic improvement in the overall attenuation capability of the material. Consequently, a wide-bandwidth, high-efficiency comprehensive wave absorption capability is achieved. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1: Preparation of insulating and microwave-absorbing liquid silicone material. The specific implementation process is as follows: 1) Preparation of fluorinated modified silicone oil Step A1: Under nitrogen protection, tetraethylenepentamine, triethylamine, and anhydrous tetrahydrofuran were premixed and allyl chloride was slowly added at room temperature. The mixture was then refluxed at 40±2℃ for 3 hours. The ratio of tetraethylenepentamine, allyl chloride, triethylamine, and anhydrous tetrahydrofuran in the reaction was 0.1 mol: 0.2 mol: 20 mL: 180 mL. After the reaction was completed, the mixture was filtered and the tetrahydrofuran was recovered by rotary evaporation to obtain intermediate 1.

[0021] Step A2: Take intermediate 1, hydrogen-containing silicone oil and ethylene glycol dimethyl ether, premix them, then add platinum catalyst and mix well. Purge with nitrogen and reflux at 80±5℃ for 7h. In the reaction, the hydrogen-containing silicone oil used is YDH616-500 (average molecular weight of 500) type end-hydrogen-containing silicone oil, and the platinum catalyst used is a caster catalyst with a platinum content of 5000ppm. The ratio of the silane content of the hydrogen-containing silicone oil, the amount of intermediate 1 and the amount of ethylene glycol dimethyl ether is 0.1mol:40mmol:300mL, and the platinum content of the platinum catalyst is 40ppm of the total amount of hydrogen-containing silicone oil and intermediate 1. After the reaction is completed, the ethylene glycol dimethyl ether is recovered by rotary evaporation under reduced pressure to obtain intermediate 2.

[0022] Step A3: Take intermediate 2, trifluoroiodopropane and dioxane premix, then add 4-dimethylaminopyridine to mix, purge with nitrogen for protection, heat to 100℃ and reflux for 12h; in the reaction, the ratio of intermediate 2, trifluoroiodopropane, 4-dimethylaminopyridine and dioxane is 50g:20mmol:2g:200mL; after the reaction is completed, cool to room temperature, add deionized water to wash, centrifuge to separate the aqueous phase, and then vacuum dry to obtain fluorinated modified silicone oil.

[0023] 2) Preparation of insulating and absorbing liquid silica gel materials The raw materials were prepared according to the following weight percentages: 38 wt% carbonyl iron powder, using YTF-HYK type micro powder with an average particle size of approximately 7 μm; 5.5 wt% fluorinated modified silicone oil, prepared in-house in this embodiment; 5 parts reactive diluent, using XSC-P1502 type low viscosity vinyl silicone oil, the same applies below; 0.3 parts defoamer, using BYK-1799 type silicone defoamer, the same applies below; 0.15 parts leveling agent, using BYK-333 type silicone leveling agent, the same applies below; the balance was liquid silicone rubber base, using ELASTOSIL® VARIO 15 type liquid silicone rubber.

[0024] Fluorinated modified silicone oil, reactive diluent, defoamer and leveling agent are premixed, carbonyl iron powder is added and mixed evenly, and finally liquid silicone rubber base glue is added and mixed evenly to obtain insulating and microwave absorbing liquid silicone material.

[0025] Example 2: Preparation of insulating and microwave-absorbing liquid silicone material. The specific implementation process is as follows: 1) Preparation of fluorinated modified silicone oil Step A1: Under nitrogen protection, tetraethylenepentamine, triethylamine, and anhydrous tetrahydrofuran were premixed and allyl chloride was slowly added at room temperature. The mixture was then refluxed at 40±2℃ for 3.5 h. The ratio of tetraethylenepentamine, allyl chloride, triethylamine, and anhydrous tetrahydrofuran in the reaction was 0.1 mol: 0.2 mol: 15 mL: 120 mL. After the reaction was completed, the mixture was filtered and the tetrahydrofuran was recovered by rotary evaporation to obtain intermediate 1.

[0026] Step A2: Take intermediate 1, hydrogen-containing silicone oil and ethylene glycol dimethyl ether, premix them, then add platinum catalyst and mix well. Purge with nitrogen and reflux at 80±5℃ for 5h. In the reaction, the hydrogen-containing silicone oil used is HF2030-M400 (average molecular weight of 400) type end-hydrogen-containing silicone oil, and the platinum catalyst used is a caster catalyst with a platinum content of 5000ppm. The ratio of the silane content of the hydrogen-containing silicone oil, the amount of intermediate 1 and the amount of ethylene glycol dimethyl ether is 0.1mol:45mmol:200mL, and the platinum content of the platinum catalyst is 60ppm of the total amount of hydrogen-containing silicone oil and intermediate 1. After the reaction is completed, the ethylene glycol dimethyl ether is recovered by rotary evaporation under reduced pressure to obtain intermediate 2.

[0027] Step A3: Take intermediate 2, trifluoroiodopropane and dioxane premix, then add 4-dimethylaminopyridine to mix, purge with nitrogen for protection, heat to 90℃ and reflux for 15h; in the reaction, the ratio of intermediate 2, trifluoroiodopropane, 4-dimethylaminopyridine and dioxane is 50g:25mmol:1.4g:150mL; after the reaction is completed, cool to room temperature, add deionized water to wash, centrifuge to separate the aqueous phase, and then vacuum dry to obtain fluorinated modified silicone oil.

[0028] 2) Preparation of insulating and absorbing liquid silica gel materials The raw materials are prepared according to the following weight percentages: 45 wt% carbonyl iron powder, using YTF-12 type micro powder with an average particle size of about 12 μm; 7.2 wt% fluorinated modified silicone oil, which is prepared in this embodiment; 8 parts reactive diluent; 0.2 parts defoamer; 0.1 parts leveling agent; and the balance is liquid silicone rubber base.

[0029] Fluorinated modified silicone oil, reactive diluent, defoamer and leveling agent are premixed, carbonyl iron powder is added and mixed evenly, and finally liquid silicone rubber base glue is added and mixed evenly to obtain insulating and microwave absorbing liquid silicone material.

[0030] Example 3: Preparation of insulating and microwave-absorbing liquid silicone material. The specific implementation process is as follows: 1) Preparation of fluorinated modified silicone oil Step A1: Under nitrogen protection, tetraethylenepentamine, triethylamine, and anhydrous tetrahydrofuran were premixed and allyl chloride was slowly added at room temperature. The mixture was then refluxed at 40±2℃ for 3.5 h. The ratio of tetraethylenepentamine, allyl chloride, triethylamine, and anhydrous tetrahydrofuran in the reaction was 0.1 mol: 0.2 mol: 158 mL: 150 mL. After the reaction was completed, the mixture was filtered and the tetrahydrofuran was recovered by rotary evaporation to obtain intermediate 1.

[0031] Step A2: Take intermediate 1, hydrogen-containing silicone oil and ethylene glycol dimethyl ether, premix them, then add platinum catalyst and mix well. Purge with nitrogen and reflux at 80±5℃ for 5.5h. In the reaction, the hydrogen-containing silicone oil used is HF2030-M400 (average molecular weight of 400) type end-hydrogen-containing silicone oil, and the platinum catalyst used is a caster catalyst with a platinum content of 5000ppm. The ratio of the silane content of the hydrogen-containing silicone oil, the amount of intermediate 1 and the amount of ethylene glycol dimethyl ether is 0.1mol:40mmol:230mL, and the platinum content of the platinum catalyst is 50ppm of the total amount of hydrogen-containing silicone oil and intermediate 1. After the reaction is completed, the ethylene glycol dimethyl ether is recovered by rotary evaporation under reduced pressure to obtain intermediate 2.

[0032] Step A3: Take intermediate 2, trifluoroiodopropane and dioxane premix, then add 4-dimethylaminopyridine to mix, purge with nitrogen for protection, heat to 95℃ and reflux for 13h; in the reaction, the ratio of intermediate 2, trifluoroiodopropane, 4-dimethylaminopyridine and dioxane is 50g:20mmol:1.7g:180mL; after the reaction is completed, cool to room temperature, add deionized water to wash, centrifuge to separate the aqueous phase, and then vacuum dry to obtain fluorinated modified silicone oil.

[0033] 2) Preparation of insulating and absorbing liquid silica gel materials The raw materials were prepared according to the following weight percentages: 42 wt% carbonyl iron powder, using YTF-HYK type micro powder with an average particle size of about 7 μm; 6.5 wt% fluorinated modified silicone oil, which was prepared in this embodiment; 7 parts reactive diluent; 0.2 parts defoamer; 0.12 parts leveling agent; and the balance being liquid silicone rubber base.

[0034] Fluorinated modified silicone oil, reactive diluent, defoamer and leveling agent are premixed, carbonyl iron powder is added and mixed evenly, and finally liquid silicone rubber base glue is added and mixed evenly to obtain insulating and microwave absorbing liquid silicone material.

[0035] Comparative Example 1 was carried out in accordance with the method of Example 3, but without the addition of fluorinated modified silicone oil, and with liquid silicone rubber base glue to make up the components, the rest were the same.

[0036] Comparative Example 2: Carbonyl iron powder was pretreated according to existing technology. The specific method was as follows: carbonyl iron powder was dispersed in an ethanol aqueous solution (volume fraction of 80%), and 5 wt% of trifluoropropanetrimethoxysilane was added to the carbonyl iron powder. The mixture was stirred and reacted at 40°C for 6 hours. The precipitate was separated by centrifugation, washed with deionized water, and dried to obtain pretreated carbonyl iron powder. The implementation method of Example 3 was followed, but the fluorinated modified silicone oil and carbonyl iron powder were replaced with 44 parts of pretreated carbonyl iron powder, and liquid silicone rubber base glue was used to make up the components. The rest were the same.

[0037] The liquid silicone material prepared above was used to test its filling capacity. The specific method was as follows: a spiral tube with a diameter of 3.2 mm was taken and the liquid silicone material was injected at 0.2 MPa at room temperature (25±2℃). The maximum injection depth Hmax and the time T90 to reach 90% of the maximum injection depth were recorded.

[0038] The liquid silicone material prepared above was injected into a mold and baked at 60°C for 4 hours to form a 2 mm thick sample. An insulation resistance tester was used to apply a 500 V DC voltage to the sample to measure the volume resistivity of the material, and the volume resistivity (ρ) was calculated based on the sample size. Using a vector network analyzer, the reflection loss of the material was measured in the frequency range of 2-18 GHz. The minimum reflection loss value (RLmin) and the bandwidth (absorption bandwidth) with a reflection loss below -10 dB were calculated.

[0039]

[0040] The table above shows the test data of Example 3, Comparative Example 1, and Comparative Example 2. It can be seen that, under the same silicone absorbing system, the insulation and absorbing ability of Example 3 are significantly better than those of the comparative examples, and it maintains good filling ability, which has better application value in precision components.

[0041] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0042] The above description is merely an example and illustration of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described, or use similar methods to replace them, as long as they do not deviate from the invention or exceed the scope defined in the claims, all of which should fall within the protection scope of the present invention.

Claims

1. An insulating and microwave-absorbing liquid silicone material, characterized in that, The components are: 38-45 wt% carbonyl iron powder, 5.5-7.2 wt% fluorinated modified silicone oil, 5-8 parts reactive diluent, 0.2-0.3 parts defoamer and 0.1-0.15 parts leveling agent, with the balance being liquid silicone rubber base adhesive; The fluorinated modified silicone oil is prepared by the following method: Step A1: Under nitrogen protection, tetraethylenepentamine, triethylamine and anhydrous tetrahydrofuran were premixed, and allyl chloride was slowly added at room temperature. Then, the temperature was controlled at 40±2℃ and refluxed for 3-3.5h to prepare intermediate 1. Step A2: Premix intermediate 1, hydrogen-containing silicone oil and ethylene glycol dimethyl ether, then add platinum catalyst and mix well. Under nitrogen protection, heat to 80±5℃ and reflux for 5-7 hours to prepare intermediate 2. Step A3: Premix intermediate 2, trifluoroiodopropane and dioxane, then add 4-dimethylaminopyridine to make a mixture, purge with nitrogen, heat to 90-100℃ and reflux for 12-15 hours to prepare fluorinated modified silicone oil.

2. The insulating and absorbing liquid silicone material according to claim 1, characterized in that, The ratio of tetraethylenepentamine, allyl chloride, triethylamine, and anhydrous tetrahydrofuran is 0.1 mol: 0.2 mol: 15-20 mL: 120-180 mL.

3. The insulating and absorbing liquid silicone material according to claim 2, characterized in that, The ratio of the silane content of the hydrogen-containing silicone oil, intermediate 1, and ethylene glycol dimethyl ether is 0.1 mol: 40-45 mmol: 200-300 mL, and the platinum content of the platinum catalyst is 40-60 ppm of the total amount of the hydrogen-containing silicone oil and intermediate 1.

4. The insulating and absorbing liquid silicone material according to claim 3, characterized in that, Hydrogen-containing silicone oil is hydrogen-terminated silicone oil.

5. The insulating and absorbing liquid silicone material according to claim 4, characterized in that, The average molecular weight of hydrogen-containing silicone oil is no higher than 1000.

6. The insulating and absorbing liquid silicone material according to claim 5, characterized in that, The ratio of intermediate 2, trifluoroiodopropane, 4-dimethylaminopyridine and dioxane is 50g: 20-25mmol: 1.4-2g: 150-200mL.

7. The insulating and absorbing liquid silicone material according to claim 1, characterized in that, The average particle size of carbonyl iron powder is 5-15 μm.

8. A method for preparing an insulating and microwave-absorbing liquid silicone material according to any one of claims 1-7, characterized in that, Specifically, the process involves premixing fluorinated modified silicone oil, reactive diluent, defoamer, and leveling agent, then adding carbonyl iron powder and mixing thoroughly, and finally adding liquid silicone rubber base and mixing thoroughly to obtain an insulating and microwave-absorbing liquid silicone material.

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