Double-dynamic network full-bio-based heat-conducting interface material as well as preparation method and application thereof

Abstract

The invention relates to a high-performance heat-conducting interface material based on a bio-based dual-dynamic covalent network as well as a preparation method and application of the high-performance heat-conducting interface material. According to the invention, biomass phenol and epoxy chloropropane react to synthesize biomass phenol epoxy resin, and then the epoxy resin and lipoic acid substances are utilized to construct a double-dynamic cross-linked network with ester bonds and disulfide bonds. Meanwhile, a graphene specific dispersing agent taking pyrene as an anchoring group is designed and synthesized, the graphene specific dispersing agent can form a'covalent and non-covalent pi-pi 'interface bonding effect with a matrix and graphene and is used for effectively linking an organic polymer and the graphene, so that the heterogeneous interface compatibility between the organic polymer / inorganic filler is improved, and after curing, the organic polymer / inorganic filler can be effectively bonded with the graphene. The whole bio-based heat conduction interface material with the double dynamic networks is prepared, the heat conduction coefficient of the whole bio-based heat conduction interface material can reach 2.889-7.243 W.m <-1 >. K <-1 >, the thermal resistance is 0.061-0.508 cm.K <-1 >, the relaxation time is 51-102 s, and the whole bio-based heat conduction interface material has good mechanical performance and sustainability and is suitable for efficient heat management of electronic equipment.

Description

Technical Field

[0001] This invention belongs to the field of thermally conductive interface materials technology, and relates to a dual dynamic network fully bio-based thermally conductive interface material, its preparation method and application. Background Technology

[0002] In recent years, with the rapid development of mobile communication technology, artificial intelligence, and high-performance computing chips, microelectronic devices and power modules are constantly evolving towards higher power density, higher integration, and miniaturization. If the heat generated during operation cannot be dissipated in time, it will lead to a sharp increase in junction temperature, seriously threatening the performance and lifespan of the equipment. Thermally conductive interface materials, as key materials filling the microscopic gaps between the chip's heat source and the heat sink, play a crucial role in establishing efficient heat flow channels. Therefore, developing interface materials with high thermal conductivity has become an urgent need to ensure the development of modern electronic systems.

[0003] Current technologies for preparing thermally conductive interface materials typically rely on petroleum-based polymers. These raw materials are non-renewable, and their permanent cross-linked networks result in materials that are "infusible and insoluble." Such materials are difficult to recycle and cause serious resource waste and "white pollution" problems. Furthermore, the global shortage and price fluctuations of fossil resources pose challenges to the stability of material costs and supply chain security. Against the backdrop of increasing heat generation in electronic devices, reducing over-reliance on petroleum resources and developing environmentally friendly and resource-sustainable new thermally conductive materials is of great significance for the coordinated development of the electronics industry and environmental protection. Although existing technologies employing dynamic covalent cross-linked networks can achieve reversible control of materials—for example, CN120590906A discloses a thermally conductive adhesive whose dynamic covalent bonds enable reworkability and self-healing properties—the thermal conductivity achieved by this technology (2.43-2.54 W·m) remains limited. -1 ·K -1 The performance level remains low, and this bottleneck severely limits its application prospects in high-power-density electronic devices. Furthermore, CN120484522A discloses a phase-change high thermal conductivity material with efficient thermal management capabilities and its preparation method. This material uses biochar instead of graphite to prepare a flexible thermally conductive material, but its preparation process is complex and the paraffin phase transition temperature in the material is low. Long-term application in high-power devices can easily lead to paraffin leaching, affecting the material's structure and performance stability.

[0004] The use of graphene as a high thermal conductivity material to enhance the thermal conductivity of polymers has always been limited by the filler-matrix interface problem. This is mainly due to the tendency of graphene to agglomerate and its poor compatibility with the polymer matrix interface, resulting in high interfacial thermal resistance between the polymer and graphene. Existing technologies typically employ surface modification to improve heterogeneous interfacial compatibility, but strong covalent modification may destroy the intrinsic structure of graphene, while weak non-covalent modification cannot provide a strong interfacial bond. Therefore, to improve the thermal conductivity of the material, a high content of thermally conductive filler is usually required, but this inevitably leads to a decrease in its fillerability and processability. In summary, it is crucial to develop a thermally conductive interface material based on biomass that can achieve efficient graphene dispersion and good interfacial compatibility between graphene and the organic matrix. Summary of the Invention

[0005] The purpose of this invention is to address the problems existing in the preparation of fully bio-based thermally conductive materials, such as poor dispersion of thermally conductive fillers, high interfacial thermal resistance between the polymer matrix and the filler, and the difficulty in simultaneously achieving both mechanical properties and remodeling ability. This invention provides a high-performance fully bio-based thermally conductive interface material based on a dual dynamic crosslinking network and its preparation method. This invention uses biomass phenols and lipoic acids as fully bio-based raw materials. A first dynamic covalent ester bond network is constructed through a ring-opening reaction between the epoxy groups of the synthesized biomass phenols and the carboxyl groups of the lipoic acids. A second dynamic reversible network is constructed through an exchange reaction between the double bonds in the biomass phenol groups and the disulfide bonds in the lipoic acids, forming a matrix with both excellent mechanical strength and remodeling ability. Meanwhile, using graphene as a thermally conductive filler, a specific dispersant was designed that can form a covalent cross-linked network with the matrix possessing a dual dynamic cross-linked network and can also form a strong interfacial coupling with graphene. This constructs a robust "molecular bridge" between the filler and the matrix, achieving an innovative combination of organic matrix and inorganic filler. This not only significantly reduces phonon scattering and contact thermal resistance at the heterogeneous interface but also enables controllable adjustment of material toughness and reshaping capability through the dual dynamic network. The preparation process is simple and environmentally friendly, and the resulting composite material exhibits excellent thermal conductivity, mechanical properties, and service life, showing broad application prospects in the field of all-bio-based high-end thermal management.

[0006] To solve the above-mentioned technical problems, the present invention is achieved through the following technical solution.

[0007] The first aspect of this invention provides a method for preparing a dual-dynamic network fully bio-based thermally conductive interface material, comprising the following steps:

[0008] (1) Biomass phenol, epichlorohydrin and catalyst are added to a container to carry out ring-opening etherification reaction; after the reaction is completed, alkaline solution is slowly added dropwise to carry out epoxidation reaction, and then washed and dried to obtain bio-based epoxy resin;

[0009] (2) Place the carboxylic acid containing the maleimide group and the solvent in a container, and add the acyl chloride reagent dropwise to carry out the reaction; then remove the solvent and excess acyl chloride reagent by rotary evaporation to obtain the carboxylic acid acyl chloride containing the maleimide group;

[0010] (3) The carboxylic acid chloride containing maleimide group obtained in step (2) is dissolved in a solvent and then slowly dripped into a container containing pyrene compounds and acid-binding agents for an ice bath reaction, followed by an acylation reaction; after the reaction is completed, the thermally conductive filler dispersant is obtained by filtration, washing and drying.

[0011] (4) After mixing the bio-based epoxy resin obtained in step (1) with the bio-based curing agent, add the catalyst, thermally conductive filler and thermally conductive filler dispersant obtained in step (3) and stir to react. Then place it in a mold for curing and cool to room temperature to obtain the product.

[0012] Preferably, the biomass phenol in step (1) is selected from one or more of magnolol and honokiol.

[0013] Preferably, the catalyst in step (1) is selected from one or more of benzyltriethylammonium chloride, tetraethylammonium bromide, and hexadecyltetramethylammonium bromide.

[0014] Preferably, the molar ratio of epichlorohydrin to biomass powder in step (1) is 11-13.5:1.

[0015] Preferably, the amount of catalyst used in step (1) is 4-6% of the mass of biomass phenols.

[0016] Preferably, the ring-opening etherification reaction in step (1) is carried out at a temperature of 80-95°C for 2-5 hours.

[0017] Preferably, the ring-opening etherification reaction in step (1) is carried out under a protective gas atmosphere.

[0018] Preferably, the protective gas is selected from one or more of nitrogen, carbon dioxide, helium, and hydrogen.

[0019] Preferably, the alkaline solution in step (1) is selected from NaOH solution; more preferably, the alkaline solution is selected from NaOH solution with a mass fraction of 20-35%.

[0020] Preferably, the molar ratio of solute to biomass phenol in the alkaline solution in step (1) is 2.3-3.3:1.

[0021] Preferably, the epoxidation reaction in step (1) is carried out at a temperature of 50-60°C for 2-4 hours.

[0022] Preferably, the carboxylic acid containing a maleimide group in step (2) is selected from one or more of 5-maleimide valerate, 6-maleimide hexanoic acid, and 11-maleamido undecanoic acid.

[0023] Preferably, the solvent in step (2) is selected from one or more of dichloromethane and ethyl acetate.

[0024] Preferably, the acyl chloride reagent in step (2) is selected from oxalyl chloride.

[0025] Preferably, the molar ratio of the acyl chloride reagent to the carboxylic acid containing the maleimide group in step (2) is 1.1-1.3:1.

[0026] Preferably, the reaction in step (2) is carried out under a protective gas atmosphere, at a temperature of 40-60°C, for a time of 2.5-5 hours.

[0027] Preferably, the protective gas is selected from one or more of nitrogen, carbon dioxide, helium, and hydrogen.

[0028] Preferably, the pyrene-containing compound in step (3) is selected from one or more of 1-hydroxypyrene and 2-hydroxypyrene.

[0029] Preferably, the molar ratio of the pyrene-containing compound in step (3) to the carboxylic acid containing the maleimide group in step (2) is 1-1.16:1.

[0030] Preferably, the acid-binding agent in step (3) is selected from one or more of triethylamine, N,N-diisopropylethylamine, and pyridine.

[0031] Preferably, the molar ratio of the acid-binding agent to the pyrene-containing compound in step (3) is 3-3.6:1.

[0032] Preferably, the solvent in step (3) is selected from one or more of dichloromethane and ethyl acetate.

[0033] Preferably, the ice bath reaction time in step (3) is 1-1.75 h.

[0034] Preferably, the acylation reaction in step (3) is carried out at a temperature of 25-40°C for 10-24 hours.

[0035] Preferably, the bio-based curing agent in step (4) is selected from one or more of D-lipoic acid, L-lipoic acid, and lipoic acid.

[0036] Preferably, the molar ratio of biomass epoxy resin to bio-based curing agent in step (4) is 1:0.5-3.

[0037] Preferably, the catalyst in step (4) is selected from one or more of 1,8-diazabicyclo[5.4.0]undec-7-ene and 4-dimethylaminopyridine.

[0038] Preferably, the amount of catalyst used in step (4) is 2-4% of the total mass of biomass epoxy resin and biomass curing agent.

[0039] Preferably, the thermally conductive filler in step (4) is selected from graphene.

[0040] Preferably, the amount of thermally conductive filler used in step (4) is 5-20% of the total mass of biomass epoxy resin and biomass curing agent.

[0041] Preferably, the amount of thermally conductive filler dispersant used in step (4) is 2-4% of the mass of the thermally conductive filler.

[0042] Preferably, the temperature of the stirring reaction in step (4) is 55-65°C and the time is 25-40 min.

[0043] Preferably, the curing in step (4) specifically involves: performing a first-stage curing reaction at 100-130℃ for 2-4 hours; followed by a second-stage curing reaction at 140-150℃ for 3-5 hours.

[0044] A second aspect of the present invention provides a dual dynamic network fully bio-based thermally conductive interface material prepared according to the above preparation method.

[0045] The third aspect of this invention provides the application of the dual dynamic network fully bio-based thermally conductive interface material prepared according to the above preparation method in heat dissipation of electronic devices.

[0046] Compared with existing technologies, the present invention has the following advantages:

[0047] (1) This invention uses biomass phenol as raw material to synthesize biomass phenol epoxy resin, and constructs a dual dynamic covalent network of epoxy-carboxyl and double bond-disulfide bond with bio-based curing agent. Through the action of dynamic covalent bond, the thermal interface material can be endowed with excellent remodelability, and the reprocessability of the thermal interface material can be realized, providing a new strategy for the development of a new generation of green electronic thermal management materials.

[0048] (2) This invention designs a graphene dispersant with pyrene as the anchoring group. First, it can form a dynamic covalent interaction with the organic polymer matrix. Second, it can form a non-covalent π-π conjugation effect with the inorganic graphene filler, enabling the organic polymer and the inorganic thermally conductive filler to form an effective connection, reducing phonon scattering between the overall interface, thereby optimizing the overall thermal resistance of the material. Finally, it endows the dual dynamic network fully bio-based thermally conductive interface material with excellent thermal conductivity: the thermal conductivity can reach 2.889-7.243 W·m. -1 ·K -1 The thermal resistance is 0.061-0.508 cm²·K·W. -1 With a relaxation time of 51-102s, it combines good mechanical properties with remodelability, making it suitable for efficient thermal management of electronic devices. Attached Figure Description

[0049] Figure 1 The relaxation time is the time of the dual dynamic network fully bio-based thermally conductive interface material prepared in Comparative Examples 2, 4 and 1 of this invention. Detailed Implementation

[0050] 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.

[0051] 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.

[0052] Example 1

[0053] A dual-dynamic network fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0054] (1) 93.9 mmol of magnolol, 1.26 mol of epichlorohydrin and 5% benzyltriethylammonium chloride of magnolol were added to a three-necked flask and the ring-opening etherification reaction was carried out at 90 °C under a nitrogen atmosphere for 3 h. After the reaction was completed, a 20% w / w NaOH solution (containing 0.2347 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 60 °C under a nitrogen atmosphere for 2 h. Then, the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0055] (2) 101.75 mmol of 6-maleimide hexanoic acid was placed in a three-necked flask and 30 mL of ethyl acetate was added. Then, 132.275 mmol of oxaloyl chloride was added dropwise under a nitrogen atmosphere and at 0 °C. The reaction was carried out under nitrogen atmosphere and at 50 °C for 3 h. After removing ethyl acetate and excess oxaloyl chloride by rotary evaporation, 6-maleimide hexanoyl chloride was obtained.

[0056] (3) Dissolve the 6-maleimide hexanoyl chloride obtained in step (2) in 50 mL of ethyl acetate, and then slowly add it dropwise to a three-necked flask containing 117.1 mmol of 1-hydroxypyrene and 0.3665 mol of triethylamine under a nitrogen atmosphere and ice bath for 1 h of ice bath reaction; then carry out acylation reaction at 25 °C for 24 h; after the reaction is completed, filter, wash with deionized water and dry with anhydrous sodium sulfite to obtain 6-maleimide hexanoic acid-pyrene-1-ester.

[0057] (4) Mix the magnolol epoxy resin and thioctic acid obtained in step (1) at a molar ratio of 1:2, add 2% of the total mass of magnolol epoxy resin and thioctic acid of 4-dimethylaminopyridine, 20% of the total mass of magnolol epoxy resin and thioctic acid of graphene and 2% of the mass of graphene of 6-maleimide hexanoic acid-pyrene-1-ester, stir and react at 60°C for 30 min, then place in a mold, carry out the first stage curing reaction at 120°C for 3 h, and then carry out the second stage curing reaction at 150°C for 5 h, and then cool to room temperature to obtain the product.

[0058] Example 2

[0059] A dual-dynamic network fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0060] (1) 85.2 mmol magnolol, 1.065 mol epichlorohydrin and 4% tetraethylammonium bromide of magnolol were added to a three-necked flask and the ring-opening etherification reaction was carried out at 85°C under a nitrogen atmosphere for 4 h. After the reaction was completed, a 35% w / w NaOH solution (containing 0.2964 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 50°C under a nitrogen atmosphere for 4 h. Then the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0061] (2) 103.07 mmol of 11-maleimino undecanoic acid was placed in a three-necked flask and 35 mL of dichloromethane was added. Then, 118.531 mmol of oxaloyl chloride was added dropwise under a nitrogen atmosphere and at 0 °C. The reaction was carried out under nitrogen atmosphere and at 40 °C for 5 h. After removing dichloromethane and excess oxaloyl chloride by rotary evaporation, 11-maleimino undecanoic acid chloride was obtained.

[0062] (3) The 11-maleimide undecanoyl chloride obtained in step (2) was dissolved in 50 mL of dichloromethane, and then slowly added dropwise to a three-necked flask containing 113.4 mmol of 2-hydroxypyrene and 0.3674 mol of N,N-diisopropylethylamine under a nitrogen atmosphere and an ice bath for 1.5 h. Then, the acylation reaction was carried out at 30 °C for 18 h. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried with anhydrous sodium sulfite to obtain 11-maleimide undecanoic acid-pyrene-1-ester.

[0063] (4) Mix the magnolol epoxy resin and D-lipoic acid obtained in step (1) at a molar ratio of 1:1, add 3% of 1,8-diazabicyclo[5.4.0]undec-7-ene, 15% of graphene, and 3% of 11-maleimide undecanoic acid-pyrene-1-ester of the total mass of magnolol epoxy resin and D-lipoic acid, stir and react at 65°C for 25 min, then place in a mold, perform the first stage curing reaction at 120°C for 2 h, and then perform the second stage curing reaction at 150°C for 4 h, and then cool to room temperature to obtain the product.

[0064] Example 3

[0065] A dual-dynamic network fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0066] (1) 101.5 mmol of magnolol, 1.218 mol of epichlorohydrin and 6% of magnolol by mass of hexadecyltetramethylammonium bromide were added to a three-necked flask and the ring-opening etherification reaction was carried out at 95°C under a nitrogen atmosphere for 2 h. After the reaction was completed, a 30% w / w NaOH solution (containing 0.3012 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 55°C under a nitrogen atmosphere for 3 h. Then, the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0067] (2) 104.5 mmol of 6-maleimide hexanoic acid was placed in a three-necked flask and 35 mL of ethyl acetate was added. Then, 135.85 mmol of oxaloyl chloride was added dropwise under a nitrogen atmosphere and at 0 °C. The reaction was carried out under nitrogen atmosphere and at 55 °C for 2.5 h. After removing ethyl acetate and excess oxaloyl chloride by rotary evaporation, 6-maleimide hexanoyl chloride was obtained.

[0068] (3) The 6-maleimide hexanoyl chloride obtained in step (2) was dissolved in 60 mL of ethyl acetate, and then slowly added dropwise to a three-necked flask containing 104.5 mmol of 1-hydroxypyrene and 0.3135 mol of pyridine under a nitrogen atmosphere and ice bath for 1.75 h. Then, the acylation reaction was carried out at 40 °C for 12 h. After the reaction was completed, the mixture was filtered, washed with deionized water, and dried with anhydrous sodium sulfite to obtain 6-maleimide hexanoic acid-pyrene-1-ester.

[0069] (4) Mix the magnolol epoxy resin and L-lipoic acid obtained in step (1) at a molar ratio of 1:0.5, add 3% of 4-dimethylaminopyridine of the total mass of magnolol epoxy resin and L-lipoic acid, 10% of graphene of the total mass of magnolol epoxy resin and L-lipoic acid, and 3% of 6-maleimide hexanoic acid-pyrene-1-ester of graphene, stir and react at 60°C for 30 min, then place in a mold, perform the first stage curing reaction at 100°C for 4 h, and then perform the second stage curing reaction at 140°C for 4 h, and then cool to room temperature to obtain the product.

[0070] Example 4

[0071] A dual-dynamic network fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0072] (1) 93.9 mmol of magnolol, 1.0329 mol of epichlorohydrin and 5% benzyltriethylammonium chloride of magnolol were added to a three-necked flask and the ring-opening etherification reaction was carried out at 90 °C under a nitrogen atmosphere for 3 h. After the reaction was completed, a 20% w / w NaOH solution (containing 0.2418 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 55 °C under a nitrogen atmosphere for 3 h. Then the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0073] (2) 109.01 mmol of 5-maleiminovalerate was placed in a three-necked flask and 40 mL of ethyl acetate was added. Then, 119.911 mmol of oxaloyl chloride was added dropwise under a nitrogen atmosphere and at 0 °C. The reaction was carried out under nitrogen atmosphere and at 60 °C for 2.5 h. After removing ethyl acetate and excess oxaloyl chloride by rotary evaporation, 5-maleiminovalerate chloride was obtained.

[0074] (3) The 5-maleimide pentanoyl chloride obtained in step (2) was dissolved in 55 mL of ethyl acetate, and then slowly added dropwise to a three-necked flask containing 119.9 mmol of 2-hydroxypyrene and 0.4244 mol of N,N-diisopropylethylamine under a nitrogen atmosphere and ice bath for 1.25 h of ice bath reaction; then the acylation reaction was carried out at 25 °C for 24 h; after the reaction was completed, the 5-maleimide pentanoic acid-pyrene-1-ester was obtained by filtration, washing with deionized water and drying with anhydrous sodium sulfite.

[0075] (4) Mix the magnolol epoxy resin and D-lipoic acid obtained in step (1) at a molar ratio of 1:3, add 4% of 1,8-diazabicyclo[5.4.0]undec-7-ene, 5% of graphene, and 2% of 5-maleimide pentanoic acid-pyrene-1-ester of the total mass of magnolol epoxy resin and D-lipoic acid, stir and react at 55°C for 40 min, then place in a mold, perform the first stage curing reaction at 110°C for 3 h, and then perform the second stage curing reaction at 140°C for 5 h, and then cool to room temperature to obtain the product.

[0076] Example 5

[0077] A dual-dynamic network fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0078] (1) 95.3 mmol of magnolol, 1.172 mol of epichlorohydrin and 4% (by weight) of benzyltriethylammonium chloride of magnolol were added to a three-necked flask and the ring-opening etherification reaction was carried out at 80 °C under a nitrogen atmosphere for 5 h. After the reaction was completed, a 25% w / w NaOH solution (containing 0.2751 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 60 °C under a nitrogen atmosphere for 2 h. Then the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0079] (2) 108.13 mmol of 6-maleimide hexanoic acid was placed in a three-necked flask and 30 mL of dichloromethane was added. Then, 135.163 mmol of oxaloyl chloride was added dropwise under a nitrogen atmosphere and at 0 °C. The reaction was carried out under nitrogen atmosphere and at 50 °C for 3 h. After removing the dichloromethane and excess oxaloyl chloride by rotary evaporation, 6-maleimide hexanoyl chloride was obtained.

[0080] (3) Dissolve the 6-maleimide hexanoyl chloride obtained in step (2) in 55 mL of dichloromethane, and then slowly add it dropwise to a three-necked flask containing 124.3 mmol of 2-hydroxypyrene and 0.3978 mol of triethylamine under a nitrogen atmosphere and ice bath for 1 h of ice bath reaction; then carry out acylation reaction at 35 °C for 15 h; after the reaction is completed, filter, wash with deionized water and dry with anhydrous sodium sulfite to obtain 6-maleimide hexanoic acid-pyrene-1-ester.

[0081] (4) Mix the magnolol epoxy resin and thioctic acid obtained in step (1) at a molar ratio of 1:2, add 2% of 1,8-diazabicyclo[5.4.0]undec-7-ene, 10% of graphene, and 2% of 6-maleimide hexanoic acid-pyrene-1-ester of the total mass of magnolol epoxy resin and thioctic acid, stir and react at 55°C for 40 min, then place in a mold, perform the first stage curing reaction at 120°C for 2 h, and then perform the second stage curing reaction at 150°C for 3 h, and then cool to room temperature to obtain the product.

[0082] Example 6

[0083] A dual-dynamic network fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0084] (1) 100 mmol magnolol, 1.26 mol epichlorohydrin and 5% tetraethylammonium chloride of magnolol were added to a three-necked flask and the ring-opening etherification reaction was carried out at 90 °C under a nitrogen atmosphere for 3 h. After the reaction was completed, a 30% w / w NaOH solution (containing 0.2755 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 50 °C under a nitrogen atmosphere for 4 h. Then the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0085] (2) 110 mmol of 5-maleiminovalerate was placed in a three-necked flask and 40 mL of ethyl acetate was added. Then, 132 mmol of oxaloyl chloride was added dropwise under a nitrogen atmosphere and at 0 °C. The reaction was carried out under nitrogen atmosphere and at 45 °C for 3.5 h. After removing ethyl acetate and excess oxaloyl chloride by rotary evaporation, 5-maleiminovalerate chloride was obtained.

[0086] (3) The 5-maleimide pentanoyl chloride obtained in step (2) was dissolved in 60 mL of ethyl acetate, and then slowly added dropwise to a three-necked flask containing 110 mmol of 1-hydroxypyrene and 0.396 mol of triethylamine under a nitrogen atmosphere and an ice bath for 1.5 h; then the acylation reaction was carried out at 25 °C for 24 h; after the reaction was completed, the mixture was filtered, washed with deionized water and dried with anhydrous sodium sulfite to obtain 5-maleimide pentanoic acid-pyrene-1-ester.

[0087] (4) Mix the magnolol epoxy resin and thioctic acid obtained in step (1) at a molar ratio of 1:1, add 2% of the total mass of magnolol epoxy resin and thioctic acid of 4-dimethylaminopyridine, 15% of the total mass of magnolol epoxy resin and thioctic acid of graphene and 3% of the mass of graphene of 5-maleimide valerate-pyrene-1-ester, stir and react at 60°C for 30 min, then place in a mold, perform the first stage curing reaction at 130°C for 3 h, and then perform the second stage curing reaction at 150°C for 5 h, and then cool to room temperature to obtain the product.

[0088] Comparative Example 1

[0089] A single dynamic network fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0090] (1) 93.9 mmol of magnolol, 1.26 mol of epichlorohydrin and 5% benzyltriethylammonium chloride of magnolol were added to a three-necked flask and the ring-opening etherification reaction was carried out at 90 °C under a nitrogen atmosphere for 3 h. After the reaction was completed, a 20% w / w NaOH solution (containing 0.2347 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 60 °C under a nitrogen atmosphere for 2 h. Then, the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0091] (2) Mix the magnolol epoxy resin and 4-4'-dithiodiphenylamine obtained in step (1) at a molar ratio of 2:1, add 2% of the total mass of magnolol epoxy resin and 4-4'-dithiodiphenylamine of 4-dimethylaminopyridine, and 20% of the total mass of magnolol epoxy resin and 4-4'-dithiodiphenylamine of graphene, stir and react at 60°C for 30 min, then place in a mold, and carry out the first stage of curing reaction at 120°C for 3 h, and then carry out the second stage of curing reaction at 150°C for 5 h, and then cool to room temperature to obtain the product.

[0092] Comparative Example 2

[0093] A single dynamic network fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0094] (1) 93.9 mmol of magnolol, 1.26 mol of epichlorohydrin and 5% benzyltriethylammonium chloride of magnolol were added to a three-necked flask and the ring-opening etherification reaction was carried out at 90 °C under a nitrogen atmosphere for 3 h. After the reaction was completed, a 20% w / w NaOH solution (containing 0.2347 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 60 °C under a nitrogen atmosphere for 2 h. Then, the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0095] (2) 101.75 mmol of 6-maleimide hexanoic acid was placed in a three-necked flask and 35 mL of ethyl acetate was added. Then, 132.275 mmol of oxaloyl chloride was added dropwise under a nitrogen atmosphere and at 0 °C. The reaction was carried out under nitrogen atmosphere and at 50 °C for 3 h. After removing ethyl acetate and excess oxaloyl chloride by rotary evaporation, 6-maleimide hexanoyl chloride was obtained.

[0096] (3) Dissolve the 6-maleimide hexanoyl chloride obtained in step (2) in 60 mL of ethyl acetate, and then slowly add it dropwise to a three-necked flask containing 92.5 mmol of 1-hydroxypyrene and 0.3665 mol of triethylamine under a nitrogen atmosphere and ice bath for 1 h of ice bath reaction; then carry out acylation reaction at 25 °C for 24 h; after the reaction is completed, filter, wash with deionized water and dry with anhydrous sodium sulfite to obtain 6-maleimide hexanoic acid-pyrene-1-ester.

[0097] (4) The magnolol epoxy resin and 4-4'-dithiodiphenylamine obtained in step (1) are mixed at a molar ratio of 2:1. 2% of the total mass of magnolol epoxy resin and 4-4'-dithiodiphenylamine, 20% of the total mass of magnolol epoxy resin and 4-4'-dithiodiphenylamine, 2% of the total mass of graphene, and 2% of the mass of graphene are added to 6-maleimide hexanoic acid-pyrene-1-ester. The mixture is stirred at 60°C for 30 min, then placed in a mold and cured at 120°C for 3 h for the first stage, followed by a second stage of curing at 150°C for 5 h. The mixture is then cooled to room temperature to obtain the final product.

[0098] Comparative Example 3

[0099] A fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0100] (1) 95.3 mmol of magnolol, 1.172 mol of epichlorohydrin and 4% of the mass of magnolol tetraethylammonium bromide were added to a three-necked flask and the ring-opening etherification reaction was carried out at 85°C under a nitrogen atmosphere for 4 h. After the reaction was completed, a 30% w / w NaOH solution (containing 0.2751 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 55°C under a nitrogen atmosphere for 3 h. Then the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0101] (2) The magnolol epoxy resin and 4-4'-diaminodicyclohexylmethane obtained in step (1) are mixed at a molar ratio of 2:1. 3% of the total mass of magnolol epoxy resin and 4-4'-diaminodicyclohexylmethane, 20% of the total mass of graphene, and 2% of the total mass of graphene are added. The mixture is stirred at 55°C for 40 min. Then it is placed in a mold and cured at 120°C for 3 h for the first stage of curing, followed by a second stage of curing at 150°C for 5 h. The mixture is then cooled to room temperature to obtain the final product.

[0102] Comparative Example 4

[0103] A fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0104] (1) 95.3 mmol of magnolol, 1.172 mol of epichlorohydrin and 4% of the mass of magnolol tetraethylammonium bromide were added to a three-necked flask and the ring-opening etherification reaction was carried out at 85°C under a nitrogen atmosphere for 4 h. After the reaction was completed, a 30% w / w NaOH solution (containing 0.2751 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 55°C under a nitrogen atmosphere for 3 h. Then the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0105] (2) 103.07 mmol of 11-maleimino undecanoic acid was placed in a three-necked flask and 35 mL of dichloromethane was added. Then, 123.684 mmol of oxaloyl chloride was added dropwise under a nitrogen atmosphere and at 0 °C. The reaction was carried out under nitrogen atmosphere and at 40 °C for 5 h. After removing dichloromethane and excess oxaloyl chloride by rotary evaporation, 11-maleimino undecanoic acid chloride was obtained.

[0106] (3) The 11-maleimide undecanoic acid chloride obtained in step (2) was dissolved in 50 mL of dichloromethane, and then slowly added dropwise to a three-necked flask containing 93.7 mmol of 1-hydroxypyrene and 0.3839 mol of triethylamine under a nitrogen atmosphere and an ice bath for 1.25 h; then the acylation reaction was carried out at 30 °C for 12 h; after the reaction was completed, the mixture was filtered, washed with deionized water and dried with anhydrous sodium sulfite to obtain 11-maleimide undecanoic acid-pyrene-1-ester.

[0107] (4) The magnolol epoxy resin and 4-4'-diaminodicyclohexylmethane obtained in step (1) are mixed at a molar ratio of 2:1. 3% of the total mass of magnolol epoxy resin and 4-4'-diaminodicyclohexylmethane, 20% of the total mass of graphene, and 2% of the total mass of graphene, 11-maleimide undecanoic acid-pyrene-1-ester are added. The mixture is stirred at 55°C for 40 min. Then, it is placed in a mold and cured at 120°C for 3 h for the first stage of curing, followed by a second stage of curing at 150°C for 5 h. The mixture is then cooled to room temperature to obtain the final product.

[0108] Comparative Example 5

[0109] A dual-dynamic network fully bio-based thermally conductive interface material, the preparation method of which specifically includes the following steps:

[0110] (1) 101.5 mmol of magnolol, 1.218 mol of epichlorohydrin and 6% of magnolol by mass of hexadecyltetramethylammonium bromide were added to a three-necked flask and the ring-opening etherification reaction was carried out at 80 °C under a nitrogen atmosphere for 5 h. After the reaction was completed, a 30% w / w NaOH solution (containing 0.3012 mol NaOH) was slowly added dropwise to the above mixture and the epoxidation reaction was carried out at 55 °C under a nitrogen atmosphere for 3 h. Then the mixture was washed with deionized water and dried with anhydrous sodium sulfite to obtain magnolol epoxy resin.

[0111] (2) Graphene was mixed with a mixed acid (V(concentrated HNO3):V(concentrated H2SO4) = 3:1) at a ratio of 1g:250mL and stirred for 6h. After the mixture cooled, it was diluted with deionized water, washed several times, filtered, and the product was placed in a freeze dryer and dried for 24h to obtain acidified graphene. A certain amount of acidified graphene was added to a solution of a certain concentration prepared by mixing coupling agent KH-550 and deionized water and stirred for 6h. After washing several times with deionized water, it was filtered and dried to obtain modified graphene.

[0112] (4) Mix the magnolol epoxy resin and D-lipoic acid obtained in step (1) at a molar ratio of 1:2, add 2% of 4-dimethylaminopyridine (total mass of magnolol epoxy resin and D-lipoic acid) and 20% of modified graphene (total mass of magnolol epoxy resin and D-lipoic acid), stir and react at 65°C for 25 min, then place in a mold, and perform the first stage curing reaction at 130°C for 3 h, followed by the second stage curing reaction at 150°C for 5 h, and then cool to room temperature to obtain the product.

[0113] Verification Example 1

[0114] The thermally conductive interface materials prepared in Examples 1-6 and Comparative Examples 1-5 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, where Figure 1 The relaxation times of the thermally conductive interface materials prepared in Examples 1, 2, and 4 of this invention are shown.

[0115] Table 1 Thermal conductivity, thermal resistance, and glass transition temperature T of thermally conductive interface materials g Relaxation time test results

[0116] sample thermal conductivity thermal resistance <![CDATA[T g ]]> Relaxation time Comparative Example 1 4.959 0.169 114 141 Comparative Example 2 5.569 0.116 117 145 Comparative Example 3 4.047 0.272 121 - Comparative Example 4 4.538 0.214 126 - Comparative Example 5 4.851 0.175 83 59 Example 1 7.243 0.061 85 50 Example 2 5.349 0.135 101 69 Example 3 4.002 0.283 126 102 Example 4 2.889 0.508 72 51 Example 5 4.727 0.183 82 54 Example 6 6.265 0.098 99 66

[0117] The results showed that the single dynamic network fully bio-based thermally conductive interface materials prepared in Comparative Examples 1 and 2, which only introduced a single epoxy-carboxyl dynamic covalent bond structure, possessed some remodeling ability, but their relaxation times were relatively high (141s and 145s, respectively), indicating that the recombination ability of the dynamic cross-linked network was limited. Comparative Examples 3 and 4, lacking any dynamic covalent bonds, did not possess remodeling ability, demonstrating the necessity of dynamic chemical structures for material remodeling. Regarding thermal conductivity, although graphene dispersants were added to Comparative Examples 2 and 4, their thermal conductivity improved compared to Comparative Examples 1 and 3 without dispersants, but their thermal conductivity coefficients remained low and their thermal resistance high, indicating that a single dynamic network or simple physical dispersion is insufficient to achieve efficient thermal conductivity. Comparative Example 5, due to the destruction of the graphene lattice during modification, showed a significant decrease in intrinsic thermal conductivity, emphasizing the crucial role of maintaining the integrity of the graphene structure in thermal conductivity. In contrast, the dual-dynamic network fully bio-based thermally conductive interface material developed in this invention achieves a covalent-non-covalent synergistic bond between the organic matrix and the inorganic filler by constructing a dual dynamic crosslinking system of epoxy-carboxyl groups and double-disulfide bonds, and adding a dispersant that can generate π-π conjugation with graphene. The formation of this structure depends on the following key factors: First, biomass phenol with a multifunctional structure was selected as the raw material, providing both epoxy groups and unsaturated double bonds, thus providing a chemical basis for constructing the dual dynamic network; second, a bio-based curing agent containing carboxyl groups and disulfide bonds was selected, which can undergo dynamic exchange reactions with epoxy groups and double bonds under mild conditions to form a reversible epoxy-carboxyl ester bond and double-disulfide bond network; in addition, by designing a bio-based dispersant with strong π-π conjugation with the graphene surface, uniform dispersion of the filler in the matrix is ​​achieved without affecting the integrity of the graphene lattice, thus enhancing interfacial interactions.

[0118] The differences in thermal conductivity data shown in the examples demonstrate the controllability and overall performance balance of this solution. The examples, through systematic adjustment of the biomass phenol type, the molar ratio of bio-based curing agent to resin, and the content of thermally conductive filler, effectively investigated the influence of each key component on the final material performance. This proves that this solution does not pursue a single extreme value for thermal conductivity, but rather prepares an interface material with high thermal conductivity, excellent dynamic performance, and good processability. For example, Example 4 used a lower graphene filler content (5%), resulting in a relatively low thermal conductivity, but the material also exhibited a shorter relaxation time (51s) and excellent reshapeability, fully demonstrating its ability to flexibly adapt to specific application scenarios. Example 1, with optimized proportions, achieved a thermal conductivity of (7.243 W·m). -1 ·K -1 ) and thermal resistance (0.061 cm²·K·W) -1All of them are superior to other comparative examples, demonstrating the superiority and creativity of the "dual dynamic network" and "π-π conjugate" collaborative design technology.

[0119] Therefore, the core of this invention lies in the synergistic solution to the problems of poor dispersibility of thermal fillers, high interfacial thermal resistance, and difficulty in balancing the dynamic and mechanical properties of materials by rationally selecting biomass phenols and bio-based curing agents, designing a dual dynamic crosslinking system, and preparing and applying graphene dispersants. This provides an effective approach for the development of fully bio-based high-performance thermally conductive interface materials.

[0120] 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 dual-dynamic network fully bio-based thermally conductive interface material, characterized in that, Includes the following steps: (1) Biomass phenol, epichlorohydrin and catalyst are added to a container to carry out ring-opening etherification reaction; after the reaction is completed, alkaline solution is slowly added dropwise to carry out epoxidation reaction, and then washed and dried to obtain bio-based epoxy resin; (2) Place the carboxylic acid containing the maleimide group and the solvent in a container, and add the acyl chloride reagent dropwise to carry out the reaction; then remove the solvent and excess acyl chloride reagent by rotary evaporation to obtain the carboxylic acid acyl chloride containing the maleimide group; (3) The carboxylic acid chloride containing maleimide group obtained in step (2) is dissolved in a solvent and then slowly dripped into a container containing pyrene compounds and acid-binding agents for an ice bath reaction, followed by an acylation reaction; after the reaction is completed, the thermally conductive filler dispersant is obtained by filtration, washing and drying. (4) After mixing the bio-based epoxy resin obtained in step (1) with the bio-based curing agent, add the catalyst, thermally conductive filler and thermally conductive filler dispersant obtained in step (3) and stir to react. Then place it in a mold for curing and cool to room temperature to obtain the product.

2. The preparation method according to claim 1, characterized in that, The biomass phenols mentioned in step (1) are selected from one or more of magnolol and honokiol.

3. The preparation method according to claim 1, characterized in that, The catalyst mentioned in step (1) is selected from one or more of benzyltriethylammonium chloride, tetraethylammonium bromide, and hexadecyltetramethylammonium bromide.

4. The preparation method according to claim 1, characterized in that, The carboxylic acid containing a maleimide group mentioned in step (2) is selected from one or more of 5-maleimide valerate, 6-maleimide hexanoic acid, and 11-maleamido undecanoic acid.

5. The preparation method according to claim 1, characterized in that, The acyl chloride reagent mentioned in step (2) is selected from oxalyl chloride.

6. The preparation method according to claim 1, characterized in that, The pyrene-containing compound mentioned in step (3) is selected from one or more of 1-hydroxypyrene and 2-hydroxypyrene.

7. The preparation method according to claim 1, characterized in that, The acid-binding agent mentioned in step (3) is selected from one or more of triethylamine, N,N-diisopropylethylamine, and pyridine.

8. The preparation method according to claim 1, characterized in that, The catalyst in step (4) is selected from one or more of 1,8-diazabicyclo[5.4.0]undec-7-ene and 4-dimethylaminopyridine.

9. The dual dynamic network fully bio-based thermally conductive interface material prepared by the preparation method according to any one of claims 1-8.

10. The application of the dual dynamic network fully bio-based thermally conductive interface material prepared by the preparation method according to any one of claims 1-8 in heat dissipation of electronic devices.

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