A remodelable organosilicon epoxy thermally conductive composite material, its preparation method and application

Abstract

This invention relates to recyclable organosilicon-epoxy thermally conductive composite materials, their preparation methods, and applications. The invention utilizes 2,4,6,8-tetramethylcyclotetrasilane, compounds containing alkenyl and epoxy groups, and compounds containing alkenyl and pyrene functional groups to prepare organosilicon-epoxy resins. Diamines containing disulfide dynamic chemical bonds are used as curing agents for the organosilicon-epoxy resins, and graphene nanosheets, graphite, and carbon nanotubes are used as thermally conductive fillers. Based on the synergistic effect of dynamic covalent chemistry and supramolecular interactions, the material is endowed with excellent dynamic properties, achieving recyclability and remodeling characteristics. Simultaneously, by introducing functional groups into the molecular chain that can form strong π-π conjugated forces with the thermally conductive fillers, a molecular anchoring effect is constructed, achieving a strong, low thermal resistance interface bond between the filler and the polymer matrix. This reduces the internal interfacial thermal resistance of the composite material, thereby effectively improving the thermal conductivity of the composite material, achieving a thermal conductivity of 3.458–14.538 W·m. ‑1 ·K ‑1 The thermal resistance can be reduced to 0.0245-0.398 cm. 2 ·K·W ‑1 The relaxation time can be reduced to 53-105 seconds.

Description

Technical Field

[0001] This invention belongs to the field of thermally conductive polymer composite materials technology, and relates to a remodelable organosilicon epoxy thermally conductive composite material, its preparation method and application. Background Technology

[0002] With the rapid development of high-power-density electronic devices, efficient thermal management has become a key bottleneck in the development of microelectronics technology. While widely used epoxy resin thermal conductive materials possess excellent adhesion and mechanical strength, their three-dimensional permanent cross-linked network leads to inherent brittleness and high internal stress, making them prone to cracking and failure during thermal cycling. Silicone resins, with their excellent flexibility, suffer from insufficient adhesion strength to the substrate and are prone to interfacial leakage. Furthermore, polymers have extremely low intrinsic thermal conductivity (~0.2 W·m). -1 ·K -1 The high proportion of inorganic thermally conductive fillers used in composite materials not only leads to a deterioration in material processability and a loss of flexibility, but also makes it difficult to further improve the thermal conductivity of composite materials due to the significant interfacial thermal resistance between the filler and the matrix.

[0003] Even more serious is the fact that the infusible and insoluble permanent cross-linked networks formed by traditional thermosetting materials such as epoxy resins and silicones make them unrecyclable after the devices have finished their service life, resulting in severe resource waste and environmental pressure. Existing technologies focus on improving a specific material property (such as thermal conductivity or adhesion) or introducing dynamic covalent bonds to impart recyclability, but at the expense of high-temperature reliability, making it difficult to achieve a balance between high performance and sustainability. Therefore, there is an urgent need in this field for an innovative molecular design strategy that can fundamentally and synergistically solve a series of interrelated challenges, including the "rigid-flexible" balance of matrix materials, interfacial adhesion reliability, the construction of efficient thermal conductivity pathways, and material recyclability. Summary of the Invention

[0004] To address the aforementioned problems, the present invention aims to overcome the limitations of existing technologies and provide a novel molecular-level solution. Through hydrosilylation, specific functionalized structural units are precisely integrated into a hybrid polymer backbone. By grafting flexible siloxane cyclic structures, flexible segments are fundamentally implanted, breaking the rigid network and endowing the matrix with intrinsic flexibility to absorb and release thermal stress. Simultaneously, active epoxy groups are introduced, preserving and optimizing the strong adhesion properties of epoxy resin to various substrates, ensuring the long-term sealing reliability of the encapsulation structure. Secondly, functional groups that can form strong π-π conjugation forces with thermally conductive fillers are introduced into the molecular chain, constructing a molecular anchoring effect. This achieves a strong, low-thermal-resistance interfacial bond between the filler and the polymer matrix, reducing the internal interfacial thermal resistance of the composite material and effectively improving its thermal conductivity. Furthermore, the synergistic effect of dynamic covalent chemistry and supramolecular interactions endows the material with excellent dynamic properties, enabling its recycling and remodeling characteristics.

[0005] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution.

[0006] The first aspect of this invention provides a method for preparing a remodelable organosilicon-epoxy thermally conductive composite material, comprising the following steps:

[0007] (1) 2,4,6,8-tetramethylcyclotetrasilane, catalyst, and compound containing alkenyl and epoxy groups are added to a container to carry out hydrosilylation reaction;

[0008] (2) After the reaction is complete, a solution containing alkenyl and pyrene functional groups is added to continue the reaction. Then the solvent is removed to obtain organosilicon epoxy resin.

[0009] (3) Add curing agent and mix, then add thermally conductive filler, heat and stir and then cure to obtain the product.

[0010] Preferably, the catalyst in step (1) is selected from caster catalysts, and the amount of the catalyst is 50-100 ppm.

[0011] Preferably, the alkenyl and epoxy group-containing compound in step (1) is selected from one or more of allyl glycidyl ether, 2,3-epoxypropyl acrylate, [[2-(2-propenoxy)phenoxy]methyl]ethylene oxide, 4-(epoxyethylene-2-ylmethoxy)butyl acrylate, 1,2-epoxy-5-hexene, 2-[(4-vinylphenoxy)methyl]ethylene oxide, and 2-[(3-vinylphenoxy)methyl]ethylene oxide.

[0012] Preferably, the molar ratio of 2,4,6,8-tetramethylcyclotetrasilane to the compound containing alkenyl and epoxy groups in step (1) is 1:2-3.

[0013] Preferably, the hydrosilylation reaction in step (1) is carried out under anhydrous and oxygen-free conditions, with a reaction temperature of 100-115℃ and a reaction time of 3-8h.

[0014] Preferably, the alkenyl and pyrene functional group compound in step (2) is selected from one or more of pyrene-1-acrylate, pyrene-1-4-maleimidebutyrate, 1-pyrene butyl acrylate, 1-pyrene methyl acrylate, 4-(pyrene-1-yl)butyl 6-maleimide hexanoate and 4-(pyrene-1-yl)butyl 3-maleimide propionate.

[0015] Preferably, the solvent used to dissolve the alkenyl and pyrene functional group compounds in step (2) is selected from one or more of toluene, xylene and benzene.

[0016] Preferably, the molar ratio of the alkenyl and pyrene functional group compound in step (2) to the 2,4,6,8-tetramethylcyclotetrasilane in step (1) is 1.05-2.5:1.

[0017] Preferably, the reaction temperature in step (2) is 100-115℃ and the reaction time is 3-8h.

[0018] Preferably, in step (2), the solvent is removed by rotary evaporation, wherein the temperature of rotary evaporation is 85-110°C.

[0019] Preferably, the curing agent in step (3) is selected from diamines containing dynamic covalent bonds.

[0020] Preferably, the diamine containing a dynamic covalent bond is selected from one or more of 4,4'-dithiodiphenylamine and cystamine.

[0021] Preferably, the molar ratio of the curing agent in step (3) to the silicone epoxy resin in step (2) is 0.5-0.75:1.

[0022] Preferably, the thermally conductive filler in step (3) is selected from one or more of graphene, graphite, and carbon nanotubes.

[0023] Preferably, the amount of thermally conductive filler used in step (3) is 10-50% of the total mass of all other components.

[0024] Preferably, the heating and stirring temperature in step (3) is 40-55℃ and the time is 5-20min.

[0025] Preferably, the curing in step (3) is specifically carried out as follows: first, a first-stage curing reaction is carried out at 100-130℃ for 2-4 hours, then a second-stage curing reaction is carried out at 140-180℃ for 2-4 hours, and finally a third-stage curing reaction is carried out at 180-195℃ for 2-4 hours.

[0026] A second aspect of the present invention provides a remodelable organosilicon epoxy thermally conductive composite material prepared according to the above-described preparation method.

[0027] A third aspect of the present invention provides the application of the remodelable organosilicon epoxy thermally conductive composite material prepared according to the above preparation method in heat dissipation of electronic devices.

[0028] Compared with existing technologies, the present invention has the following advantages:

[0029] (1) This invention uses 2,4,6,8-tetramethylcyclotetrasilane as an initiator to introduce flexible organosilicon segments and epoxy active groups, which effectively improves the brittleness of traditional epoxy resins, enhances the impact resistance and thermal cycling reliability of the material, and synergistically solves the "rigid-flexible" balance of the matrix material and the reliability of interfacial adhesion. At the same time, based on the synergistic effect of disulfide dynamic covalent chemistry and π-π supramolecular interaction of pyrene functional groups, the material is endowed with excellent dynamic properties, realizing the recycling and remodeling characteristics of the material, and the relaxation time can be reduced to 53-105s.

[0030] (2) This invention introduces pyrene groups into the molecular chain, which can form an effective π-π conjugation effect with the thermally conductive filler (graphene, graphite, or carbon nanotubes). This design constructs a robust "molecular bridge" between the resin matrix and the thermally conductive filler, greatly enhancing the interfacial bonding force and effectively reducing the phonon scattering effect between the organosilicon epoxy resin matrix and the thermally conductive filler. This achieves a strong, low-thermal-resistance interfacial bond between the filler and the polymer matrix, reducing the internal interfacial thermal resistance of the composite material, thereby effectively improving the thermal conductivity of the composite material. The thermal conductivity can reach 3.458-14.538 W·m. -1 ·K -1 The thermal resistance can be reduced to 0.0245-0.398 cm. 2 ·K·W -1 . Attached Figure Description

[0031] Figure 1 The relaxation time is the time of the remodelable organosilicon epoxy thermally conductive composite material prepared in Comparative Examples 1, 2 and 5 of this invention. Detailed Implementation

[0032] To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0033] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of the invention. Unless otherwise specified, all raw materials, reagents, instruments, and equipment used in this invention are commercially available or can be prepared by existing methods.

[0034] Example 1

[0035] A remodelable organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0036] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 50 ppm of caster catalyst was added, and then 0.3 mol of allyl glycidyl ether was slowly added dropwise. The hydrosilylation reaction was carried out at 100 °C for 3 h. The main substance of the hydrosilylation reaction was 2,4,6,8-tetramethylcyclotetrasilane.

[0037] (2) After the reaction is complete, slowly add 50 mL of acrylate-pyrene-1-ester solution (0.12 mol acrylate-pyrene-1-ester dissolved in 50 mL toluene), continue the reaction at 110 °C for 3 h, and then remove the toluene by rotary evaporation at 95 °C to obtain organosilicon epoxy resin.

[0038] (3) Add 4,4'-dithiodiphenylamine as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2). The molar ratio of 4,4'-dithiodiphenylamine to organosilicon epoxy resin is 3:4. Then, add 10% of the total mass of other components as a thermally conductive filler and heat and stir at 40°C for 5 minutes. Finally, place it in a polytetrafluoroethylene mold and cure it at 120°C for 2 hours, at 160°C for 4 hours, and at 190°C for 2 hours to obtain the final product.

[0039] Example 2

[0040] A remodelable organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0041] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 65 ppm of caster catalyst was added, and then 0.3 mol of 2,3-epoxypropyl acrylate was slowly added dropwise. The hydrosilylation reaction was carried out at 105 °C for 4 h.

[0042] (2) After the reaction is complete, slowly add 60 mL of 1-pyrene acrylate solution (0.105 mol of 1-pyrene acrylate dissolved in 60 mL of xylene), continue the reaction at 105 °C for 4 h, and then remove xylene by rotary evaporation at 95 °C to obtain organosilicon epoxy resin.

[0043] (3) Add cystamine as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2), wherein the molar ratio of cystamine to organosilicon epoxy resin is 3:4; then add graphite as a thermally conductive filler at 40% of the total mass of other components, and heat and stir at 45°C for 5 minutes; finally place it in a polytetrafluoroethylene mold and cure it at 130°C for 3 hours, at 170°C for 3 hours, and at 195°C for 2.5 hours to obtain the product.

[0044] Example 3

[0045] A remodelable organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0046] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 70 ppm of caster catalyst was added, and then 0.3 mol of [[2-(2-propenoxy)phenoxy]methyl]ethylene oxide was slowly added dropwise, and the hydrosilylation reaction was carried out at 115 °C for 3 h.

[0047] (2) After the reaction is complete, slowly add 55 mL of methyl 1-acrylate solution (0.11 mol of methyl 1-acrylate dissolved in 55 mL of toluene), and continue the reaction at 100 °C for 3.5 h. Then, remove the toluene by rotary evaporation at 105 °C to obtain organosilicon epoxy resin.

[0048] (3) Add 4,4'-dithiodiphenylamine as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2). The molar ratio of 4,4'-dithiodiphenylamine to organosilicon epoxy resin is 3:4. Then, add 15% of the total mass of carbon nanotubes as thermally conductive filler and heat and stir at 50°C for 15 min. Finally, place it in a polytetrafluoroethylene mold and cure it at 125°C for 2 h, at 180°C for 2 h, and at 190°C for 4 h to obtain the final product.

[0049] Example 4

[0050] A remodelable organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0051] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 100 ppm of caster catalyst was added, and then 0.2 mol of 4-(ethylene oxide-2-ylmethoxy)butyl acrylate was slowly added dropwise. The hydrosilylation reaction was carried out at 105 °C for 4 h.

[0052] (2) After the reaction is complete, slowly add 50 mL of acrylate-pyrene-1-ester solution (0.2 mol acrylate-pyrene-1-ester dissolved in 50 mL toluene), continue the reaction at 105 °C for 3 h, and then remove the toluene by rotary evaporation at 100 °C to obtain organosilicon epoxy resin.

[0053] (3) Add 4,4'-dithiodiphenylamine as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2). The molar ratio of 4,4'-dithiodiphenylamine to organosilicon epoxy resin is 1:2. Then, add 25% of the total mass of other components as a thermally conductive filler and heat and stir at 40°C for 10 min. Finally, place it in a polytetrafluoroethylene mold and cure it at 110°C for 4 h, at 150°C for 4 h, and at 190°C for 2 h to obtain the final product.

[0054] Example 5

[0055] A remodelable organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0056] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 60 ppm of caster catalyst was added, and then 0.2 mol of 1,2-epoxy-5-hexene was slowly added dropwise. The hydrosilylation reaction was carried out at 105 °C for 3 h.

[0057] (2) After the reaction is complete, slowly add 50 mL of 4-maleimidebutyric acid-pyrene-1-ester solution (0.2 mol 4-maleimidebutyric acid-pyrene-1-ester dissolved in 50 mL toluene), continue the reaction at 110 °C for 3 h, and then remove the toluene by rotary evaporation at 100 °C to obtain organosilicon epoxy resin.

[0058] (3) Add 4,4'-dithiodiphenylamine as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2). The molar ratio of 4,4'-dithiodiphenylamine to organosilicon epoxy resin is 1:2. Then, add 30% of the total mass of other components, a mixture of graphene and carbon nanotubes (the mass ratio of graphene to carbon nanotubes is 2:1), as a thermally conductive filler. Heat and stir at 55°C for 10 min. Finally, place it in a polytetrafluoroethylene mold and cure it at 100°C for 3 h, 140°C for 3 h, and 180°C for 3 h to obtain the final product.

[0059] Example 6

[0060] A remodelable organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0061] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 80 ppm of caster catalyst was added, and then 0.2 mol of 1,2-epoxy-5-hexene was slowly added dropwise. The hydrosilylation reaction was carried out at 100 °C for 4 h.

[0062] (2) After the reaction is complete, slowly add 100 mL of 4-(pyrene-1-yl)butyl 6-maleimide hexanoate solution (0.22 mol 4-(pyrene-1-yl)butyl 6-maleimide hexanoate dissolved in 100 mL toluene), continue the reaction at 105 °C for 4 h, and then remove the toluene by rotary evaporation at 95 °C to obtain organosilicon epoxy resin.

[0063] (3) Add 4,4'-dithiodiphenylamine as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2). The molar ratio of 4,4'-dithiodiphenylamine to organosilicon epoxy resin is 1:2. Then, add 40% of the total mass of other components, a mixture of graphene and carbon nanotubes (the mass ratio of graphene to carbon nanotubes is 4:1), as a thermally conductive filler. Heat and stir at 50°C for 15 min. Finally, place it in a polytetrafluoroethylene mold and cure it at 120°C for 2 h, 160°C for 2 h, and 180°C for 2 h to obtain the final product.

[0064] Example 7

[0065] A remodelable organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0066] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 50 ppm of caster catalyst was added, and then 0.2 mol of 2-[(4-vinylphenoxy)methyl]ethylene oxide was slowly added dropwise. The hydrosilylation reaction was carried out at 115 °C for 6 h.

[0067] (2) After the reaction is complete, slowly add 50 mL of 1-pyrene butyl acrylate solution (0.2 mol of 1-pyrene butyl acrylate dissolved in 50 mL of xylene), continue the reaction at 115 °C for 6 h, and then remove xylene by rotary evaporation at 110 °C to obtain organosilicon epoxy resin.

[0068] (3) Add 4,4'-dithiodiphenylamine as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2). The molar ratio of 4,4'-dithiodiphenylamine to organosilicon epoxy resin is 1:2. Then, add 30% of the total mass of other components, graphene as a thermally conductive filler, and heat and stir at 50°C for 10 min. Finally, place it in a polytetrafluoroethylene mold and cure it at 100°C for 2 h, 150°C for 2 h, and 180°C for 2 h to obtain the final product.

[0069] Example 8

[0070] A remodelable organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0071] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 100 ppm of caster catalyst was added, and then 0.2 mol of 2-[(3-vinylphenoxy)methyl]ethylene oxide was slowly added dropwise. The hydrosilylation reaction was carried out at 115 °C for 8 h.

[0072] (2) After the reaction is complete, slowly add 80 mL of 4-(pyrene-1-yl)butyl3-maleimide propionate solution (0.2 mol 4-(pyrene-1-yl)butyl3-maleimide propionate dissolved in 80 mL benzene), continue the reaction at 110 °C for 8 h, and then remove benzene by rotary evaporation at 85 °C to obtain organosilicon epoxy resin.

[0073] (3) Add 4,4'-dithiodiphenylamine as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2). The molar ratio of 4,4'-dithiodiphenylamine to organosilicon epoxy resin is 1:2. Then add 50% of the total mass of other components, graphite as a thermally conductive filler, and heat and stir at 40°C for 20 min. Finally, place it in a polytetrafluoroethylene mold and cure it at 120°C for 2 h, 150°C for 2 h, and 180°C for 2 h to obtain the final product.

[0074] Comparative Example 1

[0075] An organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0076] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 100 ppm of caster catalyst was added, and then 0.41 mol of allyl glycidyl ether was slowly added dropwise. The hydrosilylation reaction was carried out at 100 °C for 4 h.

[0077] (2) After the reaction is complete, the excess allyl glycidyl ether is removed by rotary evaporation at 95°C to obtain organosilicon epoxy resin.

[0078] (3) Add 4,4'-diaminodiphenylmethane as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2), wherein the molar ratio of 4,4'-diaminodiphenylmethane to organosilicon epoxy resin is 1:1; then add 40% of the total mass of other components, graphite as a thermally conductive filler, and heat and stir at 40°C for 20 min; finally place it in a polytetrafluoroethylene mold and cure it at 130°C for 3 h, at 170°C for 3 h, and at 190°C for 2 h to obtain the product.

[0079] Comparative Example 2

[0080] An organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0081] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 100 ppm of caster catalyst was added, and then 0.41 mol of 1,2-epoxy-5-hexene was slowly added dropwise. The hydrosilylation reaction was carried out at 100 °C for 4 h.

[0082] (2) After the reaction is complete, the excess 1,2-epoxy-5-hexene is removed by rotary evaporation at 100°C to obtain organosilicon epoxy resin.

[0083] (3) Add 4,4'-dithiodiphenylamine as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2), wherein the molar ratio of 4,4'-dithiodiphenylamine to organosilicon epoxy resin is 1:1; then add 30% of the total mass of other components, a mixture of graphene and carbon nanotubes (where the mass ratio of graphene to carbon nanotubes is 2:1), as a thermally conductive filler, and heat and stir at 55°C for 10 min; finally place it in a polytetrafluoroethylene mold and cure it at 100°C for 3 h, at 140°C for 3 h, and at 180°C for 3 h to obtain the product.

[0084] Comparative Example 3

[0085] A remodelable organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0086] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 70 ppm of caster catalyst was added, and then 0.3 mol of [[2-(2-propenoxy)phenoxy]methyl]ethylene oxide was slowly added dropwise, and the hydrosilylation reaction was carried out at 115 °C for 3 h.

[0087] (2) After the reaction is complete, slowly add 55 mL of methyl 1-acrylate solution (0.11 mol of methyl 1-acrylate dissolved in 55 mL of toluene), and continue the reaction at 100 °C for 3.5 h. Then, remove the toluene by rotary evaporation at 105 °C to obtain organosilicon epoxy resin.

[0088] (3) Add 4,4'-diaminodiphenylmethane as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2), wherein the molar ratio of 4,4'-diaminodiphenylmethane to organosilicon epoxy resin is 3:4; then add carbon nanotubes as thermally conductive fillers at 15% of the total mass of other components, and heat and stir at 50°C for 15 min; finally place it in a polytetrafluoroethylene mold and cure it at 125°C for 2 h, at 180°C for 2 h, and at 190°C for 4 h to obtain the product.

[0089] Comparative Example 4

[0090] A remodelable organosilicon epoxy thermally conductive composite material, the preparation method of which includes the following steps:

[0091] (1) Under anhydrous conditions, 0.1 mol of 2,4,6,8-tetramethylcyclotetrasilane was placed in a three-necked round-bottom flask, 80 ppm of caster catalyst was added, and then 0.2 mol of 1,2-epoxy-5-hexene was slowly added dropwise. The hydrosilylation reaction was carried out at 100 °C for 4 h.

[0092] (2) After the reaction is complete, slowly add 100 mL of 4-(pyrene-1-yl)butyl 6-maleimide hexanoate solution (0.22 mol 4-(pyrene-1-yl)butyl 6-maleimide hexanoate dissolved in 100 mL toluene), continue the reaction at 105 °C for 4 h, and then remove the toluene by rotary evaporation at 95 °C to obtain organosilicon epoxy resin.

[0093] (3) Add 4,4'-diaminodiphenylmethane as a curing agent and mix it with the organosilicon epoxy resin obtained in step (2), wherein the molar ratio of 4,4'-diaminodiphenylmethane to organosilicon epoxy resin is 1:2; then add 40% of the total mass of other components, a mixture of graphene and carbon nanotubes (the mass ratio of graphene to carbon nanotubes is 4:1) as a thermally conductive filler, heat and stir at 50°C for 15 min; finally place it in a polytetrafluoroethylene mold and cure it at 120°C for 2 h, at 160°C for 2 h, and at 180°C for 2 h to obtain the product.

[0094] Verification Example 1

[0095] The remodelable silicone epoxy thermally conductive composite materials prepared in Examples 1-8 and Comparative Examples 1-4 were used respectively, and their thermal conductivity (W·m) was measured according to ASTM D3574 standard using conventional methods in the art. -1 ·K -1 ), thermal resistance (cm) 2 ·K·W -1 The material's glass transition temperature (T0) is tested, and the glass transition temperature is determined using dynamic thermomechanical analysis techniques. g The remodelability (relaxation time) and other properties were tested. The test results are shown in Table 1 below. Figure 1 As shown.

[0096] Table 1 Thermal conductivity and thermal resistance T of organosilicon epoxy thermally conductive composite materials g Relaxation time test results

[0097] Comparative Example 1 2.762 0.461 145 - Comparative Example 2 8.722 0.395 134 153 Comparative Example 3 3.105 0.422 141 - Comparative Example 4 10.226 0.288 100 - Example 1 3.532 0.387 121 101 Example 2 4.488 0.327 118 99 Example 3 3.458 0.398 109 102 Example 4 9.526 0.0296 88 105 Example 5 11.422 0.0115 89 63 Example 6 14.538 0.0091 91 48 Example 7 10.514 0.0245 106 50 Example 8 5.194 0.288 101 53

[0098] The results showed that the remodelable silicone epoxy thermally conductive composite material prepared in Comparative Example 1 using 4,4'-diaminodiphenylmethane as the curing agent for the epoxy resin exhibited a lower thermal conductivity (2.762 W·m⁻¹) due to the absence of disulfide dynamic covalent bonds and functional groups that could form strong π-π conjugation forces with the thermally conductive filler. -1 ·K -1 ) and relatively high thermal resistance (0.461cm) 2 ·K·W -1 In Comparative Example 2, 4,4'-dithiodiphenylamine was used as the curing agent for the epoxy resin. Although the introduction of disulfide dynamic covalent bonds provided some remodeling properties, the material prepared from the tetrafunctional epoxy resin and 4,4'-dithiodiphenylamine had a high crosslinking density. The disulfide bonds required first breaking to generate free radicals / ions before bonding, resulting in a high activation energy for the exchange reaction and low dynamic activity, exhibiting a high relaxation time (153 s). Dynamic disulfide bonds allow polymer chain sliding and rearrangement, enabling fine-tuning of filler particles under temperature fields, thus forming a more complete thermally conductive network. Therefore, although Comparative Examples 3 and 4 also introduced pyrene functional groups that could form a strong anchoring effect with the thermally conductive filler, they did not introduce disulfide dynamic chemical bonds, thus failing to provide additional phonon transport channels, resulting in relatively high thermal resistance. Furthermore, the prepared composite materials also lacked remodeling properties. In contrast, the remodelable organosilicon-epoxy thermally conductive composite material prepared in this invention introduces disulfide dynamic chemical bonds and pyrene functional groups that can form a strong anchoring effect with the thermally conductive filler. These functional groups can undergo π-π conjugation with the thermally conductive filler, effectively reducing phonon scattering between the organosilicon-epoxy resin matrix and the thermally conductive filler. This achieves a strong, low-thermal-resistance interfacial bond between the filler and the polymer matrix, reducing the internal interfacial thermal resistance of the composite material and thus effectively improving its thermal conductivity. Furthermore, the synergistic effect of dynamic covalent chemistry and supramolecular interactions endows the material with excellent dynamic properties, enabling its recycling and remodeling characteristics.

[0099] The above detailed embodiments provide a specific description of the technical solutions involved in this invention. It should be noted that the above description is only intended to help those skilled in the art better understand the methods and ideas of this invention, and is not intended to limit the scope of the invention. Without departing from the principles of this invention, those skilled in the art can make appropriate adjustments or modifications to this invention, and such adjustments and modifications should also fall within the protection scope of this invention.

Claims

1. A method for preparing a remodelable organosilicon epoxy thermally conductive composite material, characterized in that, Includes the following steps: (1) 2,4,6,8-tetramethylcyclotetrasilane, catalyst, and compound containing alkenyl and epoxy groups are added to a container to carry out hydrosilylation reaction; (2) After the reaction is complete, a solution containing alkenyl and pyrene functional groups is added to continue the reaction. Then the solvent is removed to obtain organosilicon epoxy resin. (3) Add curing agent and mix, then add thermally conductive filler, heat and stir and then cure to obtain the product.

2. The preparation method according to claim 1, characterized in that, The catalyst used in step (1) is selected from caster catalysts, and the amount of the catalyst used is 50-100 ppm.

3. The preparation method according to claim 1, characterized in that, The alkenyl and epoxy group-containing compound in step (1) is selected from one or more of allyl glycidyl ether, 2,3-epoxypropyl acrylate, [[2-(2-propenoxy)phenoxy]methyl]ethylene oxide, 4-(epoxy-2-ylmethoxy)butyl acrylate, 1,2-epoxy-5-hexene, 2-[(4-vinylphenoxy)methyl]ethylene oxide, and 2-[(3-vinylphenoxy)methyl]ethylene oxide.

4. The preparation method according to claim 1, characterized in that, The hydrosilylation reaction described in step (1) is carried out under anhydrous and oxygen-free conditions, at a temperature of 100-115℃, and for a time of 3-8h.

5. The preparation method according to claim 1, characterized in that, The alkenyl and pyrene functional group compound mentioned in step (2) is selected from one or more of pyrene-1-acrylate, 6-maleimide-pyrene-1-acrylate, 1-pyrene butyl acrylate, 1-pyrene methyl acrylate, 4-(pyrene-1-yl)butyl 6-maleimide hexanoate, and 4-(pyrene-1-yl)butyl 3-maleimide propionate.

6. The preparation method according to claim 1, characterized in that, The solvent used to dissolve the compound containing alkenyl and pyrene functional groups in step (2) is selected from one or more of toluene, xylene and benzene.

7. The preparation method according to claim 1, characterized in that, The curing agent mentioned in step (3) is selected from diamines containing dynamic covalent bonds.

8. The preparation method according to claim 1, characterized in that, The thermally conductive filler in step (3) is selected from one or more of graphene, graphite, and carbon nanotubes.

9. The remodelable organosilicon epoxy thermally conductive composite material prepared by the preparation method according to any one of claims 1-8.

10. The application of the remodelable organosilicon epoxy thermally conductive composite material prepared by the preparation method according to any one of claims 1-8 in heat dissipation of electronic devices.

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