High-toughness bi-crosslinked network bio-based polymer composite material and application thereof

Abstract

The invention relates to a high-toughness bi-crosslinked network bio-based polymer composite material as well as a preparation method and application thereof. 2, 5-furandicarboxylic acid modified epoxy resin is prepared from 2, 5-furandicarboxylic acid from biomass, and then the modified epoxy resin and a modifier 4, 5-furandicarboxylic acid modified epoxy resin are used for preparing the epoxy resin. The composite material is prepared from 4, 4 '-bismaleimidodiphenylmethane (BDM), heat-conducting filler graphene and a diamine curing agent containing dynamic disulfide bonds through a simple one-pot method, the epoxy cured product prepared by the method has excellent thermodynamic property, degradability / reprocessability and heat-conducting property, and the adopted raw materials comprise 2, 3', 4, 4 '-bismaleimidodiphenylmethane derived from biomass. The 2, 5-furandicarboxylic acid has the characteristics of greenness, environmental protection, reproducibility and simple process, and has wide application prospects in the industrial fields of aerospace, electronic information, electrical insulation and the like.

Description

Technical Field

[0001] The present invention belongs to the field of materials, and in particular relates to a strong and tough double-crosslinked network bio-based polymer composite material and its application. Background Art

[0002] Epoxy resin is an important thermosetting resin material widely used in aerospace, electronics, composite materials, and high-performance coatings. Due to its excellent mechanical properties, heat resistance, and chemical stability, epoxy resin matrices have attracted much attention in the field of high-performance materials. However, while traditional thermosetting epoxy resins have high mechanical strength, they generally have poor toughness and are not biodegradable or recyclable. Currently, remodelable / degradable epoxy resin materials generally have poor mechanical properties. Furthermore, with the increasing demand for industrial applications, the various properties of traditional epoxy resins, such as mechanical properties and thermal conductivity, are no longer able to meet the stringent requirements of emerging fields such as high-efficiency heat dissipation materials, electrothermal equipment, and lightweight, high-strength composite materials. Therefore, it is of great significance to design a green, biodegradable / reprocessable multifunctional epoxy resin composite that combines both rigidity and toughness.

[0003] In recent years, research has explored the introduction of functional fillers or modifiers into epoxy resins to improve their mechanical properties and thermal stability. For example, CN106700073A discloses a method for preparing a modified bismaleimide resin, and CN113861804A discloses a method for preparing an aminoadamantane-graphene-modified epoxy resin. However, existing research has yet to demonstrate an epoxy resin composite material prepared from biomass materials that simultaneously exhibits high strength, high toughness, biodegradability / reprocessability, and high thermal conductivity. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems existing in the epoxy resin materials in the prior art, thereby providing a strong and tough double-crosslinked network bio-based polymer composite material and its preparation method and application. The epoxy resin cured product prepared by this method has excellent mechanical properties, degradability / reprocessability and thermal conductivity.

[0005] In order to solve the above technical problems, the present invention is achieved through the following technical solutions.

[0006] The first aspect of the present invention provides a method for preparing a strong and tough dual-crosslinked network bio-based polymer composite material, comprising the following steps:

[0007] (1) placing a 2,5-furandicarboxylic acid-modified epoxy resin, N,N-4,4'-diphenylmethane bismaleimide, a diamine curing agent, and a curing accelerator in a container, adding dichloromethane and mixing thoroughly to obtain a uniformly dispersed mixture solution; the mixing method is selected from one or more of ultrasonication and stirring;

[0008] (2) The mixture solution is placed in a mold to remove the solvent under vacuum, and then solidified, and finally cooled naturally to room temperature to obtain the product.

[0009] Preferably, the 2,5-furandicarboxylic acid-modified epoxy resin in step (1) is prepared by one of the following methods:

[0010] Method 1:

[0011] The epoxy resin and 2,5-furandicarboxylic acid are stirred in a solvent for reaction, the solvent is removed after natural cooling to room temperature, and the epoxy resin modified with 2,5-furandicarboxylic acid is obtained by vacuum drying.

[0012] Method 2:

[0013] ① Mix 2,5-furandicarboxylic acid, thionyl chloride, and a catalyst, heat and stir to react, naturally cool to room temperature, and then remove thionyl chloride by rotary evaporation, followed by drying to obtain 2,5-furandicarboxylic acid chloride;

[0014] ② dissolving eugenol and an acid-binding agent in an organic solvent 1 to obtain a solution A; dissolving the 2,5-furandicarbonyl chloride obtained in step ① in an organic solvent 1 to obtain a solution B; slowly dripping solution B into solution A under an ice bath and stirring, and stirring to react at room temperature; then placing the solution in deionized water under an ice bath and allowing it to settle; filtering the filter cake, washing it, and drying it to obtain a whole-biomass-based di(4-allyl-2-methoxyphenyl)furan-2,5-dicarboxylate;

[0015] ③ The whole biomass-based di(4-allyl-2-methoxyphenyl)furan-2,5-dicarboxylate prepared in step ② is dissolved in organic solvent 2, and m-chloroperbenzoic acid is slowly added under ice bath and stirring, followed by slow heating and continued reaction under stirring; after the reaction is completed, a sodium sulfite solution is slowly added dropwise under stirring, and after the addition is completed, the reaction is continued with stirring to quench the remaining m-chloroperbenzoic acid, and then a sodium bicarbonate solution is slowly added dropwise under stirring until the reaction solution is neutral; finally, washing, removing organic solvent 2, and drying are performed in sequence to obtain the product.

[0016] Preferably, the epoxy resin in method 1 is selected from one or more of E51, E44, and E42.

[0017] Preferably, the solvent in method 1 is selected from one or more of anhydrous chloroform, dichloromethane, and tetrahydrofuran.

[0018] Preferably, the molar ratio of the epoxy group in the epoxy resin to 2,5-furandicarboxylic acid in method 1 is 4:1.

[0019] Preferably, the stirring reaction in method 1 is carried out at a temperature of 50-100° C. and for a time of 1-10 h; more preferably, the stirring reaction is carried out at a temperature of 60-80° C. and for a time of 2-6 h.

[0020] Preferably, the catalyst in step ① of method 2 is selected from N,N-dimethylformamide.

[0021] Preferably, the molar ratio of 2,5-furandicarboxylic acid to thionyl chloride in step ① of method 2 is 1:1-3.

[0022] Preferably, the molar volume ratio of 2,5-furandicarboxylic acid to the catalyst in step ① of method 2 is 1-5:1.

[0023] It should be understood that, unless otherwise specified, the "molar volume ratio" described in the context of the present invention should be understood in accordance with the conventional manner in the art, that is, the amount of solid substances is expressed in mol, and the volume of liquid substances is expressed in mL; for example, when the molar volume ratio of 2,5-furandicarboxylic acid to the catalyst is 3:1, if the amount of 2,5-furandicarboxylic acid used is 3 mol, the amount of catalyst used is 1 mL.

[0024] Preferably, the temperature of the heating and stirring reaction in step ① of method 2 is 60-100° C. and the time is 1-8 h.

[0025] Preferably, in step ② of method 2, the acid-binding agent is selected from triethylamine; and the organic solvent 1 is selected from tetrahydrofuran.

[0026] Preferably, the molar ratio of eugenol to the acid-binding agent in step ② of method 2 is 1:1-5.

[0027] Preferably, the molar ratio of eugenol to 2,5-furandicarbonyl chloride in step ② of method 2 is 1:0.1-1.

[0028] Preferably, the organic solvent 2 in step ③ of method 2 is selected from ethyl acetate.

[0029] Preferably, the molar ratio of the whole biomass-based di(4-allyl-2-methoxyphenyl)furan-2,5-dicarboxylate to m-chloroperbenzoic acid in step ③ of method 2 is 1:1-5.

[0030] Preferably, in step ③ of method 2, the mixture is slowly heated to 30-50° C. and the reaction is continued for 24-72 hours.

[0031] Preferably, the molar ratio of m-chloroperbenzoic acid to sodium sulfite in step ③ of method 2 is 1:0.5-2.

[0032] Preferably, the diamine curing agent in step (1) is selected from one or more of 4,4'-diphenyldisulfide and cystamine.

[0033] Preferably, the curing accelerator in step (1) is selected from one or more of resorcinol, zinc acetate, 4-dimethylaminopyridine, and 2-ethyl-4-methylimidazole.

[0034] Preferably, the molar ratio of the N,N-4,4'-diphenylmethane bismaleimide to the furan ring in the 2,5-furandicarboxylic acid modified epoxy resin in step (1) is 0.5-1:1.

[0035] Preferably, the molar ratio of the diamine curing agent in step (1) to the epoxy groups in the 2,5-furandicarboxylic acid-modified epoxy resin is 1:4.

[0036] Preferably, the amount of the curing accelerator in step (1) is 1-2 wt% of the mass of the 2,5-furandicarboxylic acid-modified epoxy resin.

[0037] Preferably, the mixing method in step (1) is stirring; the stirring time is 10-60 minutes.

[0038] Preferably, graphene may be optionally added during the preparation of the mixed solution in step (1).

[0039] Preferably, in step (2), the solvent is removed in vacuo at 50-100° C. for 10-60 min.

[0040] Preferably, the curing in step (2) is a three-step curing method, wherein the first step curing temperature is 110-125°C and the time is 1-3h; the second step curing temperature is 130-145°C and the time is 1-3h; the third step curing temperature is 150-170°C and the time is 1-3h.

[0041] The second aspect of the present invention provides a strong and tough double-crosslinked network bio-based polymer composite material prepared according to the above preparation method.

[0042] The third aspect of the present invention provides the use of the strong and tough double-crosslinked network bio-based polymer composite material prepared according to the above preparation method in a thermally conductive composite material.

[0043] A fourth aspect of the present invention provides a thermally conductive composite material, comprising a strong and tough double-crosslinked network bio-based polymer composite material prepared according to the above preparation method and graphene.

[0044] A fifth aspect of the present invention provides a method for preparing the above-mentioned thermally conductive composite material, comprising the following steps:

[0045] (1) placing a 2,5-furandicarboxylic acid-modified epoxy resin, N,N-4,4'-diphenylmethane bismaleimide, graphene, a diamine curing agent, and a curing accelerator in a container, adding dichloromethane and mixing thoroughly to obtain a uniformly dispersed mixture solution; the mixing method is selected from one or more of ultrasound and stirring;

[0046] (2) The mixture solution is placed in a mold to remove the solvent under vacuum, and then solidified, and finally cooled naturally to room temperature to obtain the product.

[0047] Preferably, the 2,5-furandicarboxylic acid-modified epoxy resin in step (1) is prepared by one of the following methods:

[0048] Method 1:

[0049] The epoxy resin and 2,5-furandicarboxylic acid are stirred in a solvent for reaction, the solvent is removed after natural cooling to room temperature, and the epoxy resin modified with 2,5-furandicarboxylic acid is obtained by vacuum drying.

[0050] Method 2:

[0051] ① Mix 2,5-furandicarboxylic acid, thionyl chloride, and a catalyst, heat and stir to react, naturally cool to room temperature, and then remove thionyl chloride by rotary evaporation, followed by drying to obtain 2,5-furandicarboxylic acid chloride;

[0052] ② dissolving eugenol and an acid-binding agent in an organic solvent 1 to obtain a solution A; dissolving the 2,5-furandicarbonyl chloride obtained in step ① in an organic solvent 1 to obtain a solution B; slowly dripping solution B into solution A under an ice bath and stirring, and stirring to react at room temperature; then placing the solution in deionized water under an ice bath and allowing it to settle; filtering the filter cake, washing it, and drying it to obtain a whole-biomass-based di(4-allyl-2-methoxyphenyl)furan-2,5-dicarboxylate;

[0053] ③ The whole biomass-based di(4-allyl-2-methoxyphenyl)furan-2,5-dicarboxylate prepared in step ② is dissolved in organic solvent 2, and m-chloroperbenzoic acid is slowly added under ice bath and stirring, followed by slow heating and continued reaction under stirring; after the reaction is completed, a sodium sulfite solution is slowly added dropwise under stirring, and after the addition is completed, the reaction is continued with stirring to quench the remaining m-chloroperbenzoic acid, and then a sodium bicarbonate solution is slowly added dropwise under stirring until the reaction solution is neutral; finally, washing, removing organic solvent 2, and drying are performed in sequence to obtain the product.

[0054] Preferably, the epoxy resin in method 1 is selected from one or more of E51, E44, and E42.

[0055] Preferably, the solvent in method 1 is selected from one or more of anhydrous chloroform, dichloromethane, and tetrahydrofuran.

[0056] Preferably, the molar ratio of the epoxy group in the epoxy resin to 2,5-furandicarboxylic acid in method 1 is 4:1.

[0057] Preferably, the stirring reaction in method 1 is carried out at a temperature of 50-100° C. and for a time of 1-10 h; more preferably, the stirring reaction is carried out at a temperature of 60-80° C. and for a time of 2-6 h.

[0058] Preferably, the catalyst in step ① of method 2 is selected from N,N-dimethylformamide.

[0059] Preferably, the molar ratio of 2,5-furandicarboxylic acid to thionyl chloride in step ① of method 2 is 1:1-3.

[0060] Preferably, the molar volume ratio of 2,5-furandicarboxylic acid to the catalyst in step ① of method 2 is 1-5:1.

[0061] Preferably, the temperature of the heating and stirring reaction in step ① of method 2 is 60-100° C. and the time is 1-8 h.

[0062] Preferably, in step ② of method 2, the acid-binding agent is selected from triethylamine; and the organic solvent 1 is selected from tetrahydrofuran.

[0063] Preferably, the molar ratio of eugenol to the acid-binding agent in step ② of method 2 is 1:1-5.

[0064] Preferably, the molar ratio of eugenol to 2,5-furandicarbonyl chloride in step ② of method 2 is 1:0.1-1.

[0065] Preferably, the organic solvent 2 in step ③ of method 2 is selected from ethyl acetate.

[0066] Preferably, the molar ratio of the whole biomass-based di(4-allyl-2-methoxyphenyl)furan-2,5-dicarboxylate to m-chloroperbenzoic acid in step ③ of method 2 is 1:1-5.

[0067] Preferably, in step ③ of method 2, the mixture is slowly heated to 30-50° C. and the reaction is continued for 24-72 hours.

[0068] Preferably, the molar ratio of m-chloroperbenzoic acid to sodium sulfite in step ③ of method 2 is 1:0.5-2.

[0069] Preferably, the diamine curing agent in step (1) is selected from one or more of 4,4'-diphenyldisulfide and cystamine.

[0070] Preferably, the curing accelerator in step (1) is selected from one or more of resorcinol, zinc acetate, 4-dimethylaminopyridine, and 2-ethyl-4-methylimidazole.

[0071] Preferably, the molar ratio of the N,N-4,4'-diphenylmethane bismaleimide to the furan ring in the 2,5-furandicarboxylic acid modified epoxy resin in step (1) is 0.5-1:1.

[0072] Preferably, the molar ratio of the diamine curing agent in step (1) to the epoxy groups in the 2,5-furandicarboxylic acid-modified epoxy resin is 1:4.

[0073] Preferably, the amount of graphene used in step (1) is 10-18 wt% of the total mass of the 2,5-furandicarboxylic acid-modified epoxy resin, N,N-4,4'-diphenylmethane bismaleimide, and diamine curing agent.

[0074] Preferably, the amount of the curing accelerator in step (1) is 1-2 wt% of the mass of the 2,5-furandicarboxylic acid modified epoxy resin.

[0075] Preferably, the mixing method in step (1) is ultrasonication followed by stirring; the ultrasonication time is 10-60 min, and the stirring time is 10-60 min.

[0076] Preferably, in step (2), the solvent is removed in vacuo at 50-100° C. for 10-60 min.

[0077] Preferably, the curing in step (2) is a three-step curing method, wherein the first step curing temperature is 110-125°C and the time is 1-3h; the second step curing temperature is 130-145°C and the time is 1-3h; the third step curing temperature is 150-170°C and the time is 1-3h.

[0078] A sixth aspect of the present invention provides applications of the thermally conductive composite material in the fields of aerospace, electronic information, and electrical insulation.

[0079] Unlike existing epoxy resin materials, the present invention uses biomass-derived 2,5-furandicarboxylic acid to prepare a 2,5-furandicarboxylic acid-modified epoxy resin. The resulting composite material exhibits excellent degradability and reprocessability while also possessing exceptional strength, toughness, and thermal conductivity. While increasing crosslink density in conventional epoxy resin cured materials typically comes at the expense of reduced toughness and degradability and reprocessability, the present invention achieves both exceptional strength and excellent toughness thanks to the inclusion of flexible, dynamic disulfide bond segments in the selected diamine curing agent, which introduce highly reversible disulfide crosslinking sites into the crosslinked network. At the same time, the 2,5-furandicarboxylic acid-modified epoxy resin has a unique aromatic ring structure, which gives the cured product excellent rigidity and thermal stability. Furthermore, the Diels-Alder reaction between the additive N,N-4,4'-diphenylmethane bismaleimide (BDM) as a dienophile and the modified epoxy resin further introduces a dynamic DA bonding structure into the disulfide dynamic crosslinking network, thereby forming a dual dynamic crosslinking network. This strengthens the bonds between the molecular chains, significantly enhances the crosslinking density, and significantly increases the crosslinking density of the polymer and greatly improves its strength. This gives the material both extremely high strength and good toughness. Furthermore, the DA bonding structure between BDM and the epoxy resin matrix greatly optimizes the interfacial compatibility between the graphene thermal conductive filler and the polymer matrix, resulting in a significant increase in the thermal conductivity of the material after the addition of the graphene thermal conductive filler. In general, after modification with a curing agent containing a disulfide bond, an auxiliary agent bismaleimide, and graphene, the cured product of the present invention has surpassed the trade-off framework of strength-toughness-degradability / reprocessability that limits traditional thermosetting materials. The obtained modified cured product has excellent rigidity, toughness, degradability / reprocessability, and thermal conductivity. In addition, the raw material of the present invention uses a green and environmentally friendly renewable biomass resource 2,5-furandicarboxylic acid, which has excellent environmental performance and is suitable for industrial large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Figure 1 These are stress-strain curves obtained through tensile performance testing of the high-performance composite material prepared in Example 1 of the present invention and the epoxy resin materials prepared in Comparative Examples 1 and 2.

[0081] Figure 2 These are stress-strain curves obtained through tensile performance testing of the high-performance composite material prepared in Example 10 of the present invention and the epoxy resin materials prepared in Comparative Examples 3 and 4.

[0082] Figure 3 This is a comparison chart of differential scanning calorimetry curves of the high-performance composite material prepared in Example 10 of the present invention and the epoxy resin materials prepared in Comparative Examples 3 and 4 under a nitrogen atmosphere. DETAILED DESCRIPTION

[0083] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail with reference to the following examples. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0084] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of the present invention. Unless otherwise specified, the various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0085] Example 1

[0086] A strong and tough double-crosslinked network bio-based polymer composite material, the preparation method of which comprises the following steps:

[0087] (1) 10 g of E51 epoxy resin (containing 51 mmol of epoxy groups) and 12.75 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups to 2,5-furandicarboxylic acid in the epoxy resin is 4:1) were dissolved in 50 mL of tetrahydrofuran, and the mixture was stirred under reflux at 70 °C for 4 h. After cooling to room temperature, the solvent was removed by rotary evaporation and vacuum drying to obtain 2,5-furandicarboxylic acid-modified E51 epoxy resin.

[0088] (2) The 2,5-furandicarboxylic acid-modified E51 epoxy resin (containing 25.5 mmol epoxy groups and 12.75 mmol furan rings) obtained in step (1), 12.75 mmol N, N-4, 4'-diphenylmethane bismaleimide (the molar ratio of N, N-4, 4'-diphenylmethane bismaleimide to the furan rings in the 2,5-furandicarboxylic acid-modified E51 epoxy resin is 1:1), 6.375 mmol 4, 4'-dithiodiphenylamine and 2-ethyl-4-methylimidazole are placed in a beaker, 30 mL of dichloromethane is added and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounts for 1.5% of the mass of the modified E51 epoxy resin.

[0089] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0090] Furthermore, the polymer composite material prepared as above is used to prepare a thermal conductive composite material, and the steps are the same as above, except that graphene is also added when preparing the mixed solution in step (2), and ultrasonic dispersion is first performed for 30 minutes, and then stirred for 30 minutes to make the graphene evenly dispersed; wherein the amount of graphene is 10% of the total mass of modified E51 epoxy resin, N, N-4, 4'-diphenylmethane bismaleimide and 4, 4'-dithiodiphenylamine.

[0091] Example 2

[0092] A strong and tough double-crosslinked network bio-based polymer composite material, the preparation method of which comprises the following steps:

[0093] (1) 10 g of E44 epoxy resin (containing 44 mmol of epoxy groups) and 11 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups in the epoxy resin to 2,5-furandicarboxylic acid is 4:

[0094] 1) Dissolve in 50 mL of tetrahydrofuran, reflux under condensation at 70°C with stirring for 4 h, cool naturally to room temperature, remove the solvent by rotary evaporation, and dry in vacuo to obtain 2,5-furandicarboxylic acid-modified E44 epoxy resin.

[0095] (2) The 2,5-furandicarboxylic acid-modified E44 epoxy resin (containing 22 mmol epoxy groups and 11 mmol furan rings) obtained in step (1), 11 mmol N,N-4,4'-diphenylmethane bismaleimide (the molar ratio of N,N-4,4'-diphenylmethane bismaleimide to the furan rings in the 2,5-furandicarboxylic acid-modified E44 epoxy resin is 1:1), 5.5 mmol 4,4'-dithiodiphenylamine and 2-ethyl-4-methylimidazole are placed in a beaker, 30 mL of dichloromethane is added and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounts for 1.5% of the mass of the modified E44 epoxy resin.

[0096] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0097] Furthermore, the polymer composite material prepared as above is used to prepare a thermal conductive composite material, and the steps are the same as above, except that graphene is also added when preparing the mixed solution in step (2), and ultrasonic dispersion is first performed for 30 minutes, and then stirred for 30 minutes to make the graphene evenly dispersed; wherein the amount of graphene is 14% of the total mass of modified E44 epoxy resin, N, N-4, 4'-diphenylmethane bismaleimide and 4, 4'-dithiodiphenylamine.

[0098] Example 3

[0099] A strong and tough double-crosslinked network bio-based polymer composite material, the preparation method of which comprises the following steps:

[0100] (1) 10 g of E42 epoxy resin (containing 42 mmol of epoxy groups) and 10.5 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups in the epoxy resin to 2,5-furandicarboxylic acid is 4:

[0101] 1) Dissolve in 50 mL of tetrahydrofuran, reflux under condensation at 70°C with stirring for 4 h, cool naturally to room temperature, remove the solvent by rotary evaporation, and dry in vacuo to obtain 2,5-furandicarboxylic acid-modified E42 epoxy resin.

[0102] (2) The 2,5-furandicarboxylic acid-modified E42 epoxy resin (containing 21 mmol epoxy groups and 10.5 mmol furan rings) obtained in step (1), 10.5 mmol N, N-4, 4'-diphenylmethane bismaleimide (the molar ratio of N, N-4, 4'-diphenylmethane bismaleimide to the furan rings in the 2,5-furandicarboxylic acid-modified E42 epoxy resin is 1:1), 5.25 mmol 4, 4'-dithiodiphenylamine and 2-ethyl-4-methylimidazole are placed in a beaker, 30 mL of dichloromethane is added and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounts for 1.5% of the mass of the modified E42 epoxy resin.

[0103] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0104] Furthermore, the polymer composite material prepared as above is used to prepare a thermal conductive composite material, and the steps are the same as above, except that graphene is also added when preparing the mixed solution in step (2), and ultrasonic dispersion is first performed for 30 minutes, and then stirred for 30 minutes to make the graphene evenly dispersed; wherein the amount of graphene is 18% of the total mass of modified E42 epoxy resin, N, N-4, 4'-diphenylmethane bismaleimide and 4, 4'-dithiodiphenylamine.

[0105] Example 4

[0106] A strong and tough double-crosslinked network bio-based polymer composite material, the preparation method of which comprises the following steps:

[0107] (1) 10 g of E51 epoxy resin (containing 51 mmol of epoxy groups) and 12.75 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups in the epoxy resin to 2,5-furandicarboxylic acid is 4:

[0108] 1) Dissolve in 50 mL of tetrahydrofuran, reflux under condensation at 70°C with stirring for 4 h, cool naturally to room temperature, remove the solvent by rotary evaporation, and dry in vacuo to obtain 2,5-furandicarboxylic acid-modified E51 epoxy resin.

[0109] (2) The 2,5-furandicarboxylic acid-modified E51 epoxy resin (containing 25.5 mmol epoxy groups and 12.75 mmol furan rings) obtained in step (1), 9.5625 mmol N, N-4, 4'-diphenylmethane bismaleimide (the molar ratio of N, N-4, 4'-diphenylmethane bismaleimide to the furan rings in the 2,5-furandicarboxylic acid-modified E51 epoxy resin is 0.75:1), 6.375 mmol 4, 4'-dithiodiphenylamine and 2-ethyl-4-methylimidazole are placed in a beaker, 30 mL of dichloromethane is added and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounts for 1.5% of the mass of the modified E51 epoxy resin.

[0110] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0111] Furthermore, the polymer composite material prepared as above is used to prepare a thermal conductive composite material, and the steps are the same as above, except that graphene is also added when preparing the mixed solution in step (2), and ultrasonic dispersion is first performed for 30 minutes, and then stirred for 30 minutes to make the graphene evenly dispersed; wherein the amount of graphene is 10% of the total mass of modified E51 epoxy resin, N, N-4, 4'-diphenylmethane bismaleimide and 4, 4'-dithiodiphenylamine.

[0112] Example 5

[0113] A strong and tough double-crosslinked network bio-based polymer composite material, the preparation method of which comprises the following steps:

[0114] (1) 10 g of E44 epoxy resin (containing 44 mmol of epoxy groups) and 11 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups in the epoxy resin to 2,5-furandicarboxylic acid is 4:

[0115] 1) Dissolve in 50 mL of tetrahydrofuran, reflux under condensation at 70°C with stirring for 4 h, cool naturally to room temperature, remove the solvent by rotary evaporation, and dry in vacuo to obtain 2,5-furandicarboxylic acid-modified E44 epoxy resin.

[0116] (2) The 2,5-furandicarboxylic acid-modified E44 epoxy resin (containing 22 mmol of epoxy groups and 11 mmol of furan rings) obtained in step (1), 8.25 mmol of N,N-4,4'-diphenylmethane bismaleimide (the molar ratio of N,N-4,4'-diphenylmethane bismaleimide to the furan rings in the 2,5-furandicarboxylic acid-modified E44 epoxy resin is 0.75:1), 5.5 mmol of 4,4'-dithiodiphenylamine and 2-ethyl-4-methylimidazole are placed in a beaker, 30 mL of dichloromethane is added and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounts for 1.5% of the mass of the modified E44 epoxy resin.

[0117] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0118] Furthermore, the polymer composite material prepared as above is used to prepare a thermal conductive composite material, and the steps are the same as above, except that graphene is also added when preparing the mixed solution in step (2), and ultrasonic dispersion is first performed for 30 minutes, and then stirred for 30 minutes to make the graphene evenly dispersed; wherein the amount of graphene is 14% of the total mass of modified E44 epoxy resin, N, N-4, 4'-diphenylmethane bismaleimide and 4, 4'-dithiodiphenylamine.

[0119] Example 6

[0120] A strong and tough double-crosslinked network bio-based polymer composite material, the preparation method of which comprises the following steps:

[0121] (1) 10 g of E42 epoxy resin (containing 42 mmol of epoxy groups) and 10.5 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups in the epoxy resin to 2,5-furandicarboxylic acid is 4:

[0122] 1) Dissolve in 50 mL of tetrahydrofuran, reflux under condensation at 70°C with stirring for 4 h, cool naturally to room temperature, remove the solvent by rotary evaporation, and dry in vacuo to obtain 2,5-furandicarboxylic acid-modified E42 epoxy resin.

[0123] (2) The 2,5-furandicarboxylic acid-modified E42 epoxy resin (containing 21 mmol of epoxy groups and 10.5 mmol of furan rings) obtained in step (1), 7.875 mmol of N,N-4,4'-diphenylmethane bismaleimide (the molar ratio of N,N-4,4'-diphenylmethane bismaleimide to the furan rings in the 2,5-furandicarboxylic acid-modified E42 epoxy resin is 0.75:1), 5.25 mmol of 4,4'-dithiodiphenylamine and 2-ethyl-4-methylimidazole are placed in a beaker, 30 mL of dichloromethane is added and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounts for 1.5% of the mass of the modified E42 epoxy resin.

[0124] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0125] Furthermore, the polymer composite material prepared as above is used to prepare a thermal conductive composite material, and the steps are the same as above, except that graphene is also added when preparing the mixed solution in step (2), and ultrasonic dispersion is first performed for 30 minutes, and then stirred for 30 minutes to make the graphene evenly dispersed; wherein the amount of graphene is 18% of the total mass of modified E42 epoxy resin, N, N-4, 4'-diphenylmethane bismaleimide and 4, 4'-dithiodiphenylamine.

[0126] Example 7

[0127] A strong and tough double-crosslinked network bio-based polymer composite material, the preparation method of which comprises the following steps:

[0128] (1) 10 g of E51 epoxy resin (containing 51 mmol of epoxy groups) and 12.75 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups in the epoxy resin to 2,5-furandicarboxylic acid is 4:

[0129] 1) Dissolve in 50 mL of tetrahydrofuran, reflux under condensation at 70°C with stirring for 4 h, cool naturally to room temperature, remove the solvent by rotary evaporation, and dry in vacuo to obtain 2,5-furandicarboxylic acid-modified E51 epoxy resin.

[0130] (2) The 2,5-furandicarboxylic acid-modified E51 epoxy resin (containing 25.5 mmol epoxy groups and 12.75 mmol furan rings) obtained in step (1), 6.375 mmol N, N-4, 4'-diphenylmethane bismaleimide (the molar ratio of N, N-4, 4'-diphenylmethane bismaleimide to the furan rings in the 2,5-furandicarboxylic acid-modified E51 epoxy resin is 0.5:1), 6.375 mmol 4, 4'-dithiodiphenylamine and 2-ethyl-4-methylimidazole are placed in a beaker, 30 mL of dichloromethane is added and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounts for 1.5% of the mass of the modified E51 epoxy resin.

[0131] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0132] Furthermore, the polymer composite material prepared as above is used to prepare a thermal conductive composite material, and the steps are the same as above, except that graphene is also added when preparing the mixed solution in step (2), and ultrasonic dispersion is first performed for 30 minutes, and then stirred for 30 minutes to make the graphene evenly dispersed; wherein the amount of graphene is 10% of the total mass of modified E51 epoxy resin, N, N-4, 4'-diphenylmethane bismaleimide and 4, 4'-dithiodiphenylamine.

[0133] Example 8

[0134] A strong and tough double-crosslinked network bio-based polymer composite material, the preparation method of which comprises the following steps:

[0135] (1) 10 g of E44 epoxy resin (containing 44 mmol of epoxy groups) and 11 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups in the epoxy resin to 2,5-furandicarboxylic acid is 4:

[0136] 1) Dissolve in 50 mL of tetrahydrofuran, reflux under condensation at 70°C with stirring for 4 h, cool naturally to room temperature, remove the solvent by rotary evaporation, and dry in vacuo to obtain 2,5-furandicarboxylic acid-modified E44 epoxy resin.

[0137] (2) The 2,5-furandicarboxylic acid-modified E44 epoxy resin (containing 22 mmol epoxy groups and 11 mmol furan rings) obtained in step (1), 5.5 mmol N, N-4, 4'-diphenylmethane bismaleimide (the molar ratio of N, N-4, 4'-diphenylmethane bismaleimide to the furan rings in the 2,5-furandicarboxylic acid-modified E44 epoxy resin is 0.5:1), 5.5 mmol 4, 4'-dithiodiphenylamine and 2-ethyl-4-methylimidazole are placed in a beaker, 30 mL of dichloromethane is added and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounts for 1.5% of the mass of the modified E44 epoxy resin.

[0138] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0139] Furthermore, the polymer composite material prepared as above is used to prepare a thermal conductive composite material, and the steps are the same as above, except that graphene is also added when preparing the mixed solution in step (2), and ultrasonic dispersion is first performed for 30 minutes, and then stirred for 30 minutes to make the graphene evenly dispersed; wherein the amount of graphene is 14% of the total mass of modified E44 epoxy resin, N, N-4, 4'-diphenylmethane bismaleimide and 4, 4'-dithiodiphenylamine.

[0140] Example 9

[0141] A strong and tough double-crosslinked network bio-based polymer composite material, the preparation method of which comprises the following steps:

[0142] (1) 10 g of E42 epoxy resin (containing 42 mmol of epoxy groups) and 10.5 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups in the epoxy resin to 2,5-furandicarboxylic acid is 4:

[0143] 1) Dissolve in 50 mL of tetrahydrofuran, reflux under condensation at 70°C with stirring for 4 h, cool naturally to room temperature, remove the solvent by rotary evaporation, and dry in vacuo to obtain 2,5-furandicarboxylic acid-modified E42 epoxy resin.

[0144] (2) The 2,5-furandicarboxylic acid-modified E42 epoxy resin (containing 21 mmol epoxy groups and 10.5 mmol furan rings) obtained in step (1), 5.25 mmol N, N-4, 4'-diphenylmethane bismaleimide (the molar ratio of N, N-4, 4'-diphenylmethane bismaleimide to the furan rings in the 2,5-furandicarboxylic acid-modified E42 epoxy resin is 0.5:1), 5.25 mmol 4, 4'-dithiodiphenylamine and 2-ethyl-4-methylimidazole are placed in a beaker, 30 mL of dichloromethane is added and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounts for 1.5% of the mass of the modified E42 epoxy resin.

[0145] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0146] Furthermore, the polymer composite material prepared as above is used to prepare a thermal conductive composite material, and the steps are the same as above, except that graphene is also added when preparing the mixed solution in step (2), and ultrasonic dispersion is first performed for 30 minutes, and then stirred for 30 minutes to make the graphene evenly dispersed; wherein the amount of graphene is 18% of the total mass of modified E42 epoxy resin, N, N-4, 4'-diphenylmethane bismaleimide and 4, 4'-dithiodiphenylamine.

[0147] Example 10

[0148] First, the preparation of the all-biomass-based epoxy resin EUFU-EP is carried out, which specifically includes the following steps:

[0149] ① Mix 50 mmol of 2,5-furandicarboxylic acid, 100 mmol of thionyl chloride, and 0.02 mL of N,N-dimethylformamide, heat and stir at 80°C for 5 h, cool to room temperature, and then vacuum evaporate to remove the thionyl chloride. The mixture is then dried to obtain 2,5-furandicarboxylic acid chloride in a yield of 99.2%.

[0150] ② 90 mmol of eugenol and 225 mmol of triethylamine were dissolved in 150 mL of tetrahydrofuran to obtain solution A; 45 mmol of 2,5-furandicarbonyl chloride prepared in step ① was dissolved in 150 mL of tetrahydrofuran to obtain solution B; solution B was slowly added dropwise to solution A under ice bath and stirring. After the addition was complete, stirring was continued for 30 minutes, and the reaction was stirred at room temperature for 24 hours; the mixture was then placed in 2000 mL of deionized water under ice bath and allowed to settle for 20 minutes; the filter cake was filtered, washed with deionized water six times, and dried to obtain di(4-allyl-2-methoxyphenyl)furan-2,5-dicarboxylate based on whole biomass with a yield of 95.5%;

[0151] ③ 40 mmol of the biomass-based bis(4-allyl-2-methoxyphenyl)furan-2,5-dicarboxylate prepared in step ② was dissolved in 50 mL of ethyl acetate. 120 mmol of m-chloroperbenzoic acid was slowly added under ice bath and stirring. Stirring was continued for 40 min after the addition was completed. The mixture was then slowly heated to 40°C with stirring and the reaction was continued for 48 h. After the reaction was completed, a 10% sodium sulfite solution (containing 120 mmol of sodium sulfite) was slowly added dropwise under stirring. After the addition was completed, stirring was continued for 2 h to quench the remaining m-chloroperbenzoic acid. A 10% sodium bicarbonate solution was then slowly added dropwise under stirring until the reaction solution became neutral. Finally, the mixture was washed with deionized water four times, the ethyl acetate was removed by rotary evaporation, and the mixture was dried to obtain the bio-based epoxy resin bis(2-methoxy-4-(oxirane-2-ylmethyl)phenyl)furan-2,5-dicarboxylate (EUFU-EP) with a yield of 96%.

[0152] Furthermore, the EUFU-EP prepared above is used to prepare a strong and tough double-crosslinked network bio-based polymer composite material, which specifically includes the following steps:

[0153] (1) 20 mmol of EUFU-EP (containing 40 mmol of epoxy groups and 20 mmol of furan rings), 10 mmol of N,N-diphenylmethane bismaleimide (the molar ratio of N,N-4,4'-diphenylmethane bismaleimide to furan rings in EUFU-EP is 0.5:1), 10 mmol of 4,4'-dithiodiphenylamine, and 2-ethyl-4-methylimidazole were placed in a beaker, 30 mL of dichloromethane was added, and the mixture was stirred for 30 min to obtain a uniformly dispersed mixture solution; the 2-ethyl-4-methylimidazole accounted for 1.5% of the mass of EUFU-EP.

[0154] (2) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then the mixture is placed in an oven for curing; the curing procedure is: first, curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, the mixture is naturally cooled to room temperature.

[0155] Furthermore, the polymer composite material prepared above was used to prepare a thermally conductive composite material, and the steps were the same as above, except that graphene was also added when preparing the mixed solution in step (1), and ultrasonic dispersion was first performed for 30 minutes, and then stirred for 30 minutes to ensure that the graphene was evenly dispersed; wherein the amount of graphene used was 18% of the total mass of EUFU-EP, N,N-4,4'-diphenylmethane bismaleimide and 4,4'-dithiodiphenylamine.

[0156] Comparative Example 1

[0157] A polymer composite material, the preparation method of which comprises the following steps:

[0158] (1) 10 g of E51 epoxy resin (containing 51 mmol of epoxy groups) and 12.5 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups in the epoxy resin to 2,5-furandicarboxylic acid is 4:

[0159] 1) Dissolve in 50 mL of tetrahydrofuran, reflux under condensation at 70°C with stirring for 4 h, cool naturally to room temperature, remove the solvent by rotary evaporation, and dry in vacuo to obtain 2,5-furandicarboxylic acid-modified E51 epoxy resin.

[0160] (2) The 2,5-furandicarboxylic acid-modified E51 epoxy resin (containing 25.5 mmol of epoxy groups and 12.75 mmol of furan rings) obtained in step (1), 6.375 mmol of 4,4'-diaminodiphenylmethane, and 2-ethyl-4-methylimidazole were placed in a beaker, 30 mL of dichloromethane was added, and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounted for 1.5% of the mass of the modified E51 epoxy resin.

[0161] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0162] Furthermore, the polymer composite material prepared above was used to prepare a thermally conductive composite material, and the steps were the same as above, except that graphene was also added when preparing the mixed solution in step (2), and ultrasonic dispersion was first performed for 30 minutes, and then stirred for 30 minutes to ensure that the graphene was evenly dispersed; the amount of graphene used was 18% of the total mass of the modified E51 epoxy resin and 4,4'-diaminodiphenylmethane.

[0163] Comparative Example 2

[0164] A polymer composite material, the preparation method of which comprises the following steps:

[0165] (1) 10 g of E51 epoxy resin and 12.5 mmol of 2,5-furandicarboxylic acid (the molar ratio of epoxy groups in the epoxy resin to 2,5-furandicarboxylic acid is 4:1) were dissolved in 50 mL of tetrahydrofuran, and the mixture was stirred under reflux at 70°C for 4 h. After cooling to room temperature, the solvent was removed by rotary evaporation and vacuum drying to obtain 2,5-furandicarboxylic acid-modified E51 epoxy resin.

[0166] (2) The 2,5-furandicarboxylic acid-modified E51 epoxy resin (containing 25.5 mmol of epoxy groups and 12.75 mmol of furan rings) obtained in step (1), 6.375 mmol of 4,4'-dithiodiphenylamine, and 2-ethyl-4-methylimidazole were placed in a beaker, 30 mL of dichloromethane was added, and stirred for 30 min to obtain a uniformly dispersed mixture solution; wherein the 2-ethyl-4-methylimidazole accounted for 1.5% of the mass of the modified E51 epoxy resin.

[0167] (3) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then placed in an oven for curing; the curing procedure is: first curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, it is naturally cooled to room temperature.

[0168] Furthermore, the polymer composite material prepared above was used to prepare a thermal conductive composite material, and the steps were the same as above, except that graphene was also added when preparing the mixed solution in step (2), and ultrasonic dispersion was first performed for 30 minutes, and then stirred for 30 minutes to ensure that the graphene was evenly dispersed; the amount of graphene used was 18% of the total mass of the modified E51 epoxy resin and 4,4'-dithiodiphenylamine.

[0169] Comparative Example 3

[0170] A polymer composite material, the preparation method of which comprises the following steps:

[0171] (1) 20 mmol of EUFU-EP (containing 40 mmol of epoxy groups and 20 mmol of furan rings), 10 mmol of 4,4'-dithiodiphenylamine, and 2-ethyl-4-methylimidazole were placed in a beaker, 30 mL of dichloromethane was added, and stirred for 30 min to obtain a uniformly dispersed mixture solution; the 2-ethyl-4-methylimidazole accounted for 1.5% of the mass of EUFU-EP.

[0172] (2) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then the mixture is placed in an oven for curing; the curing procedure is: first, curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, the mixture is naturally cooled to room temperature.

[0173] Furthermore, the polymer composite material prepared above was used to prepare a thermally conductive composite material, and the steps were the same as above, except that graphene was also added when preparing the mixed solution in step (1), and ultrasonic dispersion was first performed for 30 minutes, and then stirred for 30 minutes to ensure uniform dispersion of the graphene; wherein the amount of graphene used was 18% of the total mass of EUFU-EP and 4,4'-dithiodiphenylamine.

[0174] Comparative Example 4

[0175] A polymer composite material, the preparation method of which comprises the following steps:

[0176] (1) 20 mmol of EUFU-EP (containing 40 mmol of epoxy groups and 20 mmol of furan rings), 10 mmol of 4,4'-diaminodiphenylmethane, and 2-ethyl-4-methylimidazole were placed in a beaker, 30 mL of dichloromethane was added, and stirred for 30 min to obtain a uniformly dispersed mixture solution; the 2-ethyl-4-methylimidazole accounted for 1.5% of the mass of EUFU-EP.

[0177] (2) The mixture solution is placed in a mold, the solvent is removed in a vacuum at 70°C for 30 minutes, and then the mixture is placed in an oven for curing; the curing procedure is: first, curing at 120°C for 2 hours, then curing at 140°C for 2 hours, and finally curing at 160°C for 2 hours; after curing, the mixture is naturally cooled to room temperature.

[0178] Furthermore, the polymer composite material prepared above was used to prepare a thermally conductive composite material, and the steps were the same as above, except that graphene was also added when preparing the mixed solution in step (1), and ultrasonic dispersion was first performed for 30 minutes, and then stirred for 30 minutes to ensure that the graphene was evenly dispersed; the amount of graphene used was 18% of the total mass of EUFU-EP and 4,4'-diaminodiphenylmethane.

[0179] Verification Example 1

[0180] The tensile strength (MPa), elongation at break (%) of the composite materials prepared in Examples 1-10 and Comparative Examples 1-4, and the thermal conductivity (W·m -1 ·K -1 ) were tested, and the results are shown in Table 1 below. In addition, the glass transition temperatures of Example 10 and Comparative Examples 3 and 4 were tested using conventional methods in the art.

[0181] Table 1 Tensile strength, elongation at break and thermal conductivity

[0182]

[0183] The results show that the epoxy resin materials of Comparative Examples 1 and 4 are cured with the traditional commercial curing agent 4,4'-diaminodiphenylmethane (DDM) and the modified epoxy resin. The stress-strain curve shows that the strength is relatively high, both around 70MPa, but the elongation at break is relatively low, with Comparative Example 1 having an elongation at break of only 7.5%, which is an obvious brittle material. The epoxy resin materials of Comparative Examples 2 and 3 are cured with the modified epoxy resin using 4,4'-dithiodiphenylamine, which is similar in structure to DDM. Compared with DDM, 4,4'-dithiodiphenylamine introduces dynamic disulfide bonds into the cured cross-linked network, thereby obtaining excellent degradability / reprocessing capabilities. However, due to the weak strength of the disulfide bonds, which is far behind the strength of the carbon-carbon bonds in DDM, the strength and toughness of Comparative Examples 2 and 3 are significantly weaker than those of Comparative Examples 1 and 4. This can be seen from the Figure 1 It can be seen from the stress-strain curve in .

[0184] In contrast, the high-performance composite material of the present invention introduces a dynamic DA bonding structure into the disulfide dynamic cross-linking network through N, N-4, 4'-diphenylmethane bismaleimide, forming a dual dynamic cross-linking network, which enhances the bonding between molecular chains, thereby significantly enhancing the cross-linking density of the polymer and greatly improving its strength. This makes the material have extremely high strength while also having good toughness. As can be seen from Table 1, after BDM modification, the tensile strength of Example 1 is increased from 22.2 MPa to 90.1 MPa compared with Comparative Example 2. a, the elongation at break increased from 3.4% to 18.3%, and the tensile strength and elongation at break of Example 1 exceeded those of Comparative Example 1 using the commercial curing agent DDM. Compared with Comparative Example 3, the tensile strength of Example 10 increased from 23.8 MPa to 103.5 MPa, and the elongation at break increased from 4.8% to 20.2%, and the tensile strength and elongation at break of Example 10 exceeded those of Comparative Example 4 using the commercial curing agent DDM. This shows that the double cross-linked network has a great effect on improving the mechanical properties of the material, and from the attached Figure 2 It can be seen that before BDM modification, the glass transition temperature of Comparative Example 3 is 113°C, which is much lower than the glass transition temperature of the epoxy resin material prepared using the commercial curing agent DDM in Comparative Example 4. This is also because the strength of the disulfide bond in 4,4'-dithiodiphenylamine is quite different from that of the carbon-carbon bond in 4,4'-diaminodiphenylmethane. After BDM modification, the glass transition temperature of Example 10 is increased to 202°C, exceeding that of Comparative Example 4. This means that the cross-linking density of the double cross-linked network constructed by DA bonds and disulfide bonds has exceeded that of the cross-linked network constructed by the traditional DDM curing agent, and the strength of the two under mutual synergy also exceeds that of the carbon-carbon bond in the DDM curing agent.

[0185] It can be seen from Table 1 that although 18% of graphene thermal conductive filler is added to the thermal conductive composite material prepared in the comparative example, the effect is poor and the improvement of the thermal conductivity is limited. However, the thermal conductive composite material in Examples 1-10 effectively improves the interface compatibility between the graphene thermal conductive filler and the polymer matrix through the DA bonding structure introduced by N, N-4, 4'-diphenylmethane bismaleimide, so that the thermal conductivity of the material is greatly improved after the addition of the graphene thermal conductive filler. It can be seen from Table 1 that compared with Comparative Example 2, the thermal conductivity of Example 3 is increased from 1.1 W·m -1 ·K -1 Increased to 3.6W·m -1 ·K -1 Compared with Comparative Example 3, the thermal conductivity of Example 10 is improved from 1.1 W·m -1 ·K -1 Increased to 3.8W·m -1 ·K -1 .

[0186] The above detailed description of the analytical methods involved in the present invention provides a detailed introduction. It should be noted that the above description is intended solely to help those skilled in the art better understand the methods and concepts of the present invention, and is not intended to limit the relevant content. Without departing from the principles of the present invention, those skilled in the art may make appropriate adjustments or modifications to the present invention, and such adjustments and modifications shall also fall within the scope of protection of the present invention.

Claims

1. A method for preparing a strong and tough double-crosslinked network bio-based polymer composite material, characterized in that: The following steps are included: (1) placing a 2,5-furandicarboxylic acid-modified epoxy resin, N,N-4,4'-diphenylmethane bismaleimide, a diamine curing agent, and a curing accelerator in a container, adding dichloromethane and mixing thoroughly to obtain a uniformly dispersed mixture solution; the mixing method is selected from one or more of ultrasonication and stirring; (2) The mixture solution is placed in a mold to remove the solvent under vacuum, and then solidified, and finally cooled naturally to room temperature to obtain the product.

2. The preparation method according to claim 1, characterized in that The 2,5-furandicarboxylic acid-modified epoxy resin in step (1) is prepared by one of the following methods: Method 1: The epoxy resin and 2,5-furandicarboxylic acid are stirred in a solvent for reaction, the solvent is removed after natural cooling to room temperature, and the epoxy resin modified with 2,5-furandicarboxylic acid is obtained by vacuum drying. Method 2: ① Mix 2,5-furandicarboxylic acid, thionyl chloride, and a catalyst, heat and stir to react, naturally cool to room temperature, and then remove thionyl chloride by rotary evaporation, followed by drying to obtain 2,5-furandicarboxylic acid chloride; ② dissolving eugenol and an acid-binding agent in an organic solvent 1 to obtain a solution A; dissolving the 2,5-furandicarbonyl chloride obtained in step ① in an organic solvent 1 to obtain a solution B; slowly dripping solution B into solution A under an ice bath and stirring, and stirring to react at room temperature; then placing the solution in deionized water under an ice bath and allowing it to settle; filtering the filter cake, washing it, and drying it to obtain a whole-biomass-based di(4-allyl-2-methoxyphenyl)furan-2,5-dicarboxylate; ③ The whole biomass-based di(4-allyl-2-methoxyphenyl)furan-2,5-dicarboxylate prepared in step ② is dissolved in organic solvent 2, and m-chloroperbenzoic acid is slowly added under ice bath and stirring, followed by slow heating and continued reaction under stirring; after the reaction is completed, a sodium sulfite solution is slowly added dropwise under stirring, and after the addition is completed, the reaction is continued with stirring to quench the remaining m-chloroperbenzoic acid, and then a sodium bicarbonate solution is slowly added dropwise under stirring until the reaction solution is neutral; finally, washing, removing organic solvent 2, and drying are performed in sequence to obtain the product.

3. The preparation method according to claim 1, characterized in that The epoxy resin in step (1) is selected from one or more of E51, E44, and E42.

4. The preparation method according to claim 1, characterized in that The diamine curing agent in step (1) is selected from one or more of 4,4'-diphenyldisulfide and cystamine.

5. The preparation method according to claim 1, characterized in that The curing accelerator in step (1) is selected from one or more of resorcinol, zinc acetate, 4-dimethylaminopyridine, and 2-ethyl-4-methylimidazole.

6. The preparation method according to claim 1, characterized in that The molar ratio of the N, N-4, 4'-diphenylmethane bismaleimide to the furan ring in the epoxy resin modified with 2, 5-furandicarboxylic acid in step (1) is 0.5-1:

1.

7. The preparation method according to claim 1, characterized in that The curing in step (2) is a three-step curing method, wherein the first step curing temperature is 110-125°C and the time is 1-3 hours; the second step curing temperature is 130-145°C and the time is 1-3 hours; and the third step curing temperature is 150-170°C and the time is 1-3 hours.

8. A strong and tough double-crosslinked network bio-based polymer composite material prepared according to the preparation method according to any one of claims 1 to 7.

9. Use of a strong and tough double-crosslinked network bio-based polymer composite material prepared according to the preparation method of any one of claims 1 to 7 in a thermally conductive composite material.

10. A thermally conductive composite material, characterized in that: The invention comprises a strong and tough double-crosslinked network bio-based polymer composite material prepared according to any one of the preparation methods of claims 1 to 7 and graphene.

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