A bio-based hyperbranched polymer epoxy resin and its preparation method and application

Abstract

The present invention relates to the technical field of high-performance polymer resins, and in particular, to a bio-based hyperbranched polymer epoxy resin and a preparation method and application thereof. The method prepares linear vanillin epoxy resin, dynamic covalent bond vanillin hyperbranched epoxy resin and dynamic covalent bond hyperbranched carboxyl-terminated polyester respectively, and then dynamically crosslinks and mixes the three. The bio-based hyperbranched polymer epoxy resin can be used to prepare recyclable epoxy resin and recyclable carbon fiber composite material. The preparation method has a simple process and is suitable for industrial production; the bio-based hyperbranched polymer epoxy resin can be quickly reshaped and chemically degraded and recycled under mild conditions, and the performance retention rate of the recycled resin is high; the two materials have excellent mechanical properties, heat resistance, solvent resistance, hydrolysis resistance, creep resistance and corrosion resistance, and can be used in wind turbine blades, lightweight automotive materials, hydrogen energy and hydrogen storage bottles for fuel cells and other fields.

Description

Technical Field

[0001] The present invention relates to the technical field of high-performance polymer resins, and in particular to a bio-based hyperbranched polymer epoxy resin and a preparation method and application thereof. Background Art

[0002] Epoxy resin has excellent mechanical properties, thermal properties, dimensional stability, processing properties and chemical stability, and is widely used in electronic packaging materials, composite materials, adhesives and coatings. However, due to the highly chemically cross-linked three-dimensional network, epoxy resin is difficult to recycle. Therefore, it is urgent to develop recycling technology for epoxy resin and its composite materials.

[0003] In the field of polymer chemistry, dynamic covalent bonds can be reversibly broken and formed under appropriate conditions, and have the advantages of reversibility and stability.

[0004] Thermosetting resins based on dynamic covalent chemistry can achieve self-healing, welding and repeated processing of thermosetting resins. However, the existing new resin matrix properties based on dynamic covalent chemistry, such as resin strength, modulus, glass transition temperature, etc., are still somewhat behind practical applications. Chinese Patent 202110634681.7 discloses a dual dynamic covalent bond hybridized thermosetting resin, preparation method, application and repair cycle recycling method, which solves the problems of low strength and poor water resistance of imine polymers by copolymerizing highly polar electron-donating hydrazone dynamic covalent bonds with imine dynamic bonds. Chinese Patent 202111586552.1 discloses a selectively disassembled epoxy polymer based on dual dynamic covalent bond "parallel interlocking" cross-linking, using an amino compound with dynamic covalent bonds containing disulfide bonds and imine bonds as an epoxy resin curing agent to achieve the recycling and reuse of effective components.

[0005] However, the preparation methods of the above technologies are complicated and the preparation costs are high, which has caused serious limitations on practical application and promotion. Summary of the invention

[0006] The technical problem to be solved by the present invention is to provide a bio-based hyperbranched polymer epoxy resin and a preparation method and application thereof.

[0007] The technical solution of the present invention to solve the above technical problems is as follows:

[0008] The invention provides a method for preparing a bio-based hyperbranched polymer epoxy resin, wherein a linear vanillin epoxy resin, a dynamic covalent bond vanillin hyperbranched epoxy resin and a dynamic covalent bond hyperbranched carboxyl-terminated polyester are prepared respectively, and then the three are dynamically cross-linked to obtain a dynamic covalent bond hyperbranched epoxy resin.

[0009] Furthermore, the preparation method of the linear vanillin epoxy resin comprises the following steps:

[0010] S1-1, mixing vanillin and a triamine compound in a first organic solvent and reacting them at a reaction temperature of 20 to 40° C. for a reaction time of 0.5 to 2 h;

[0011] S1-2, mixing the product obtained in step S1-1 with epichlorohydrin, adding a catalyst, and reacting at 60-80° C. for 4-6 hours;

[0012] S1-3, adding a second organic solvent and a sodium hydroxide aqueous solution to the product obtained in step S1-2, and continuing the reaction at 0-10° C. for 4-6 hours; wherein the mass of sodium hydroxide in the sodium hydroxide aqueous solution accounts for 10% to 40% of the total mass of the solution;

[0013] S1-4, after the reaction of step S1-3 is completed, the obtained product is sequentially washed with water, separated, and distilled under reduced pressure to obtain the linear vanillin epoxy resin;

[0014] The mass ratio of the vanillin, the triamine compound, the epichlorohydrin, the catalyst, the sodium hydroxide aqueous solution, the first organic solvent, and the second organic solvent is 1.0:0.28~1.0:(4.0~6.0):(0.02~0.03):(4.1~5.0):(6~8):(10~13.5).

[0015] Further, in step S1-1, the first organic solvent is ethanol or methanol; the triamine compound is one or more of trimethylolpropane tris[poly(propylene glycol)amine]ethyl ether, melamine and tris(2-aminoethyl)amine; the second organic solvent is one of ethylene glycol, methyl ether, cyclohexanone, n-butanol, tetrahydrofuran, ethyl acetate and dichloromethane;

[0016] In the step S1-2, the catalyst is one of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, and trioctylmethylammonium chloride.

[0017] Furthermore, the preparation method of the dynamic covalent bond vanillin hyperbranched epoxy resin comprises the following steps:

[0018] S2, stirring the linear vanillin epoxy resin, the dihydroxy monomer, the catalyst and the third organic solvent at 60 to 80° C. for 4 to 12 hours to obtain the dynamic covalent bond vanillin hyperbranched epoxy resin;

[0019] The mass ratio of the linear vanillin epoxy resin, the dihydroxy monomer, the catalyst and the third organic solvent is 1.0:(0.23-0.34):(0.009-0.01):(2.34-4.0);

[0020] The dihydroxy monomer in step S2 is one of bisphenol A, bisphenol F, and hydroquinone; the third organic solvent is tetrahydrofuran or dichloromethane; the catalyst is one of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, and trioctylmethylammonium chloride.

[0021] Furthermore, the chemical structure of the dynamic covalent vanillin hyperbranched epoxy resin is shown in general formula (1), general formula (2) or general formula (3):

[0022]

[0023] Among them, R1 is represented by Or general formula (4):

[0024]

[0025] In the structural formula of R1, * indicates the position of connection with R2; in the general formula (4), x+y+z=5-6;

[0026] R2 is expressed as In the structural formula of R2, * indicates the position of connection to R1, and ** indicates the position of connection to R3 or location;

[0027] R3 is expressed as

[0028] Wherein, *** indicates the position connected to R2.

[0029] Furthermore, the preparation method of the dynamic covalent bond hyperbranched carboxyl-terminated polyester comprises the following steps:

[0030] S3-1. Stir ethylenediamine and methyl acrylate in an ice bath for 8 to 10 hours, then add a fourth organic solvent, heat to 60 to 80°C, add diethylenetriamine and react for 4 to 6 hours to obtain an amino-terminated hyperbranched polymer; the mass ratio of the ethylenediamine, methyl acrylate, diethylenetriamine and the fourth organic solvent is 1.0:(2.8 to 20.0):(3.7 to 26.1):(1.6 to 5.0).

[0031] S3-2, adding 4-formylbenzoic acid to the amino-terminated hyperbranched polymer, stirring and reacting for 0.5 to 2 hours to obtain the dynamic covalent hyperbranched carboxyl-terminated polyester;

[0032] The mass ratio of the amino-terminated hyperbranched polymer to the 4-formylbenzoic acid is 1.0:(0.55-0.67).

[0033] Furthermore, the chemical structure of the dynamic covalent hyperbranched carboxyl-terminated polyester is shown in general formula (5), general formula (6) or general formula (7):

[0034]

[0035] Among them, R4 is represented by Wherein, * indicates the position connected to R5 or R7;

[0036] R5 is expressed as Wherein, ** indicates the position connected to R4 or R7, and *** indicates the position connected to R6;

[0037] R6 is represented by Wherein, **** indicates the position connected to R5, ***** indicates the position connected to -COOH;

[0038] R7 is represented by: Among them, **** indicates the same as R 5或 The position where R7 is connected, and ****** indicates the position where it is connected to R4.

[0039] Furthermore, the three are dynamically cross-linked, comprising the following steps:

[0040] S4. Mix the linear vanillin epoxy resin, the dynamic covalent bond vanillin hyperbranched epoxy resin and the dynamic covalent bond hyperbranched terminal carboxyl polyester and stir them evenly; the mass ratio of the vanillin epoxy resin, the dynamic covalent bond hyperbranched epoxy resin and the dynamic covalent bond hyperbranched terminal carboxyl polyester is 1:0.07:(0.63~1.18).

[0041] The invention provides a bio-based hyperbranched polymer epoxy resin, which is prepared by the above-mentioned preparation method.

[0042] The present invention provides the use of the above-mentioned bio-based hyperbranched polymer epoxy resin in wind turbine blades, automobile lightweight materials or hydrogen storage bottles for hydrogen energy and fuel cells.

[0043] The present invention also provides a recyclable epoxy resin, which is prepared by using the above-mentioned bio-based hyperbranched polymer epoxy resin.

[0044] The present invention also provides a method for preparing the recyclable epoxy resin as described above, wherein the bio-based hyperbranched polymer epoxy resin is poured into a mold and cured at 80° C.-120° C. for 1 to 4 hours to obtain the recyclable epoxy resin.

[0045] The present invention also provides a recyclable carbon fiber composite material, which is prepared by using the above-mentioned bio-based hyperbranched polymer epoxy resin.

[0046] The present invention also provides a method for preparing the above-mentioned recyclable carbon fiber composite material, comprising the following steps:

[0047] The carbon fiber cloth is fully impregnated with the bio-based hyperbranched polymer epoxy resin; after impregnation, the carbon fiber cloth is taken out and dried at 40 to 60° C. for 2 to 3 hours to obtain a carbon fiber cloth prepreg;

[0048] 7 to 8 layers of the carbon fiber cloth prepreg are stacked and placed in a mold, hot-pressed at 100 to 120° C. and 10 to 15 MPa for 30 to 60 minutes, then cured at 100 to 120° C. for 2 to 4 hours, and taken out after natural cooling to obtain the recyclable carbon fiber composite material.

[0049] The beneficial effects of the present invention are:

[0050] (1) The preparation method of the bio-based hyperbranched polymer epoxy resin of the present invention has a simple process, readily available raw materials, and is suitable for industrial production;

[0051] (2) The bio-based hyperbranched polymer epoxy resin of the present invention has the functions of strengthening, toughening, reshaping and degradation and recycling of epoxy resin and carbon fiber composite materials;

[0052] (3) The bio-based hyperbranched polymer epoxy resin of the present invention, based on the structure of multiple dynamic covalent bonds of imine bonds and ester exchange, enables the bio-based hyperbranched polymer epoxy resin to achieve rapid remodeling and chemical degradation recovery under mild conditions, and at the same time, the performance retention rate of the recycled resin is high;

[0053] (4) The bio-based hyperbranched polymer epoxy resin and its carbon fiber composite material of the present invention have excellent mechanical properties, heat resistance, solvent resistance, hydrolysis resistance, creep resistance and corrosion resistance, are suitable for large-scale industrial production, and can be used in the fields of wind turbine blades, lightweight automotive materials, hydrogen energy and hydrogen storage bottles for fuel cells. DETAILED DESCRIPTION

[0054] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0055] The method for preparing the bio-based hyperbranched polymer epoxy resin of the present invention comprises the following steps: preparing a linear vanillin epoxy resin, a dynamic covalent bond vanillin hyperbranched epoxy resin and a dynamic covalent bond hyperbranched terminal carboxyl polyester respectively, and then dynamically crosslinking the three to obtain a dynamic covalent bond hyperbranched epoxy resin.

[0056] The present invention designs a dynamic covalent vanillin hyperbranched epoxy resin and a dynamic covalent hyperbranched carboxyl-terminated polyester with excellent water resistance, high-temperature creep resistance, thermal and mechanical properties through multiple dynamic covalent bonds, and then mixes them with a linear vanillin epoxy resin to obtain an easily recyclable bio-based hyperbranched polymer epoxy resin, so that it can achieve the advantage of controllable degradation and recycling under mild conditions.

[0057] Preferably, the method for preparing linear vanillin epoxy resin comprises the following steps:

[0058] S1-1. Mix vanillin and a triamine compound in a first organic solvent and react at a reaction temperature of 20 to 40° C. for a reaction time of 0.5 to 2 h.

[0059] Further preferably, in this step, the first organic solvent is ethanol or methanol; and the triamine compound is one or more of trimethylolpropane tris[poly(propylene glycol)amine]ethyl ether, melamine and tris(2-aminoethyl)amine.

[0060] S1-2, mixing the product obtained in step S1-1 with epichlorohydrin, adding a catalyst, and reacting at 60-80° C. for 4-6 hours.

[0061] Further preferably, after the reaction is completed, epichlorohydrin is removed by reduced pressure distillation at 80-100° C., and the remaining product is dissolved in a second organic solvent; the second organic solvent used in this step is one of ethylene glycol, methyl ether, cyclohexanone, n-butanol, tetrahydrofuran, ethyl acetate, and dichloromethane; the catalyst is one of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, and trioctylmethylammonium chloride.

[0062] S1-3, mechanically stirring the final product obtained in step S1-2, adding sodium hydroxide aqueous solution and reacting for 4 to 6 hours in an ice bath, and continuing to react for 4 to 6 hours at 0 to 10° C.; wherein the mass of sodium hydroxide in the sodium hydroxide aqueous solution accounts for 10% to 40% of the total mass of the solution.

[0063] After the reaction of step S1-4 and step S1-3 is completed, the obtained product is filtered, washed with water, separated, and distilled under reduced pressure to obtain a linear vanillin epoxy resin. Specifically, the organic layer after separation is dried with anhydrous sodium sulfate and then distilled under reduced pressure to remove the organic solvent to obtain a vanillin epoxy resin VANEP with a yield of 85-90% and an epoxy value of 0.27-0.39 mol / 100g.

[0064] In the above-mentioned steps of preparing linear vanillin epoxy resin, the mass ratio of vanillin, triamine compound, epichlorohydrin, catalyst, sodium hydroxide aqueous solution, first organic solvent and second organic solvent is 1.0:0.28~1.0:(4.0~6.0):(0.02~0.03):(4.1~5.0):(6~8):(10~13.5).

[0065] The preparation method of dynamic covalent bond vanillin hyperbranched epoxy resin comprises the following steps:

[0066] S2. Stir and react the linear vanillin epoxy resin, the dihydroxy monomer, the catalyst and the third organic solvent at 60 to 80° C. for 4 to 12 hours to obtain a dynamic covalent bond vanillin hyperbranched epoxy resin.

[0067] The mass ratio of linear vanillin epoxy resin, dihydroxy monomer, catalyst and third organic solvent is 1.0:(0.23-0.34):(0.009-0.01):(2.34-4.0);

[0068] Preferably, the dihydroxy monomer in step S2 is one of bisphenol A, bisphenol F, and hydroquinone; the third organic solvent is tetrahydrofuran or dichloromethane; and the catalyst is one of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, and trioctylmethylammonium chloride.

[0069] Preferably, the chemical structure of the dynamic covalent vanillin hyperbranched epoxy resin is as shown in general formula (1), general formula (2) or general formula (3):

[0070]

[0071] Among them, R1 is expressed as Or general formula (4):

[0072]

[0073] In the structural formula of R1, * indicates the position of connection with R2; in the general formula (4), x+y+z=5-6;

[0074] R2 is expressed as In the structural formula of R2, * indicates the position of connection to R1, and ** indicates the position of connection to R3 or location;

[0075] R3 is expressed as

[0076] Wherein, *** indicates the position connected to R2.

[0077] The preparation method of the dynamic covalent bond hyperbranched carboxyl-terminated polyester comprises the following steps:

[0078] S3-1. Stir ethylenediamine and methyl acrylate in an ice bath for 8 to 10 hours, then add a fourth organic solvent, heat to 60 to 80°C, add diethylenetriamine and react for 4 to 6 hours to obtain an amino-terminated hyperbranched polymer; the mass ratio of ethylenediamine, methyl acrylate, diethylenetriamine and the fourth organic solvent is 1.0:(2.8 to 20.0):(3.7 to 26.1):(1.6 to 5.0); the fourth organic solvent is one of methanol, ethanol, ethyl acetate, tetrahydrofuran and dichloromethane.

[0079] S3-2, adding 4-formylbenzoic acid to the amino-terminated hyperbranched polymer, stirring and reacting for 0.5 to 2 hours to obtain a dynamic covalent hyperbranched carboxyl-terminated polyester.

[0080] More preferably, in step S3-2, after stirring the reaction for 0.5 to 2 hours, the fourth organic solvent is removed by reduced pressure distillation at 40 to 60° C. to obtain a dynamic covalent hyperbranched carboxyl-terminated polyester.

[0081] The mass ratio of the amino-terminated hyperbranched polymer to the 4-formylbenzoic acid is 1.0:(0.55-0.67).

[0082] Preferably, the chemical structure of the dynamic covalent hyperbranched carboxyl-terminated polyester is as shown in general formula (5), general formula (6) or general formula (7):

[0083]

[0084] Among them, R4 is represented by Wherein, * indicates the position connected to R5 or R7;

[0085] R5 is expressed as Wherein, ** indicates the position connected to R4 or R7, and *** indicates the position connected to R6;

[0086] R6 is represented by Wherein, **** indicates the position connected to R5, ***** indicates the position connected to -COOH;

[0087] R7 is represented by: Among them, **** indicates the same as R 5或 The position where R7 is connected, and ****** indicates the position where it is connected to R4.

[0088] The prepared linear vanillin epoxy resin, dynamic covalent bond vanillin hyperbranched epoxy resin and dynamic covalent bond hyperbranched carboxyl-terminated polyester are mixed to prepare a bio-based hyperbranched polymer epoxy resin, comprising the following steps:

[0089] S4, mixing the linear vanillin epoxy resin, the dynamic covalent bond vanillin hyperbranched epoxy resin and the dynamic covalent bond hyperbranched carboxyl-terminated polyester and stirring them evenly.

[0090] The bio-based hyperbranched polymer epoxy resin of the present invention is prepared by the above-mentioned preparation method; the bio-based hyperbranched polymer epoxy resin has excellent water resistance, high-temperature creep resistance, thermal and mechanical properties, and has the advantage of controllable degradation and recycling under mild conditions.

[0091] The recyclable epoxy resin of the present invention has a preparation method comprising the following steps: pouring a bio-based hyperbranched polymer epoxy resin into a mold and curing the resin at 80°C-120°C for 1-4 hours to obtain the recyclable epoxy resin; the mass ratio of the vanillin epoxy resin, the dynamic covalent bond hyperbranched epoxy resin and the dynamic covalent bond hyperbranched terminal carboxyl polyester is 1:0.07:(0.63-1.18).

[0092] In addition, the recyclable epoxy resin reprocessing and recycling method is to crush the product cured in step S4, and then hot press it at 80°C to 120°C and 2 to 5MPa for 30 to 60 minutes to obtain the reprocessed recycled epoxy resin.

[0093] The chemical degradation recovery method of the recyclable epoxy resin is as follows: immersing the product cured in step S4 in a 0.10-0.20 mol / L acid solution, degrading at 30-70° C. for 30-60 min, and then drying the degradation solution at 60-100° C. for 1-2 h to obtain the epoxy resin recovered by chemical degradation.

[0094] The acid solution is one of hydrochloric acid solution, formic acid solution and acetic acid solution. The acid solution is one of acid aqueous solution, acid N,N-dimethylformamide solution, acid ethanol solution and acid methanol solution. The mass ratio of the solidified material to the HCl solution is 1:(8-10).

[0095] The recyclable carbon fiber composite material of the present invention is prepared by using the above-mentioned bio-based hyperbranched polymer epoxy resin.

[0096] The preparation method of the recyclable carbon fiber composite material is specifically as follows: the bio-based hyperbranched polymer epoxy resin is impregnated into the carbon fiber cloth. After the impregnation is completed, the carbon fiber cloth is taken out and dried at 40-60°C for 2-3 hours to obtain a carbon fiber cloth prepreg, 7-8 layers of the prepared carbon fiber cloth prepreg are stacked together and put into a mold, hot pressed at 100-120°C and 10-15MPa for 30-60 minutes, and then post-cured at 100-120°C for 2-4 hours, and taken out after natural cooling to obtain the recyclable carbon fiber composite material of the present invention.

[0097] In addition, the specific steps of making recycled carbon fiber cloth from the recyclable carbon fiber composite material are as follows:

[0098] The carbon fiber composite material of the present invention is immersed in a 0.1-0.2 mol / L acid solution and degraded at 60-70° C. for 30-60 min. The carbon fiber cloth obtained by degradation is dried at 60-80° C. for 6-10 h to obtain a regenerated carbon fiber cloth.

[0099] The specific steps of making a recycled carbon fiber composite material from the recyclable carbon fiber composite material are as follows:

[0100] The degradation liquid obtained by degradation is evaporated to remove the acid solution to obtain oligomers, and the obtained oligomers are fully impregnated with recycled carbon fiber cloth, and then dried at 40-60°C for 2-3 hours to obtain recycled carbon fiber prepreg, 7-8 layers of the above-mentioned recycled carbon fiber cloth prepreg are stacked together and put into a mold, hot pressed at 100-120°C and 10-15MPa for 30-60 minutes, and then post-cured at 100-120°C for 2-4 hours, and taken out after natural cooling to obtain a recycled epoxy resin carbon fiber composite material. Among them, the acid solution is one of hydrochloric acid solution, formic acid solution, and acetic acid solution. The acid solution is one of an acid aqueous solution, an acid N,N-dimethylformamide solution, an acid ethanol solution, and an acid methanol solution.

[0101] The present invention is illustrated by means of specific embodiments below:

[0102] Example 1

[0103] In this embodiment, a bio-based hyperbranched polymer epoxy resin is first prepared, and then a recyclable epoxy resin material, an epoxy resin material recycled by reshaping processing, and an epoxy resin material recycled by chemical degradation are respectively prepared, and the corresponding parameters are tested.

[0104] (1) 456.0 g (3 mol) of vanillin and 440.0 g (1 mol) of trimethylolpropane tri[poly(propylene glycol)amine]ethyl ether were stirred in 3648.0 g of ethanol solution at 30° C. for 0.5 h.

[0105] (2) The product obtained above was mixed and dissolved with 2700.0g of epichlorohydrin, 13.7g of tetrabutylammonium bromide was added, and the mixture was stirred at 80°C for 4h, and then the epichlorohydrin was removed by vacuum distillation at 100°C. The product was dissolved in 6159.0g of ethyl acetate, and 1869.6g of 40wt.% sodium hydroxide aqueous solution was added during mechanical stirring and the mixture was continued to react for 6h in an ice bath. After the reaction was completed, the mixture was filtered, washed with water, and separated. The organic layer was dried with anhydrous sodium sulfate and the organic solvent was removed by vacuum distillation to obtain a linear vanillin epoxy resin VANEP with an epoxy value of 0.27mol / 100g.

[0106] (3) 3896.0 g (4 mol) of VANEP, 913.2 g (3 mol) of bisphenol A, 39.0 g of tetrabutylammonium bromide and 9120.0 g of tetrahydrofuran were stirred and reacted at 70° C. for 6 h to obtain a dynamic covalent hyperbranched epoxy resin VANEHBP. GPC test showed that its number average molecular weight was 4739 g / mol and the epoxy value was 0.13 mol / 100 g.

[0107] (4) 60.1 g (1 mol) of ethylenediamine and 172.2 g (2 mol) of methyl acrylate were stirred in an ice bath for 8 h, 96.2 g of methanol was added, the temperature was raised to 60° C., and 224.4 g (2 mol) of diethylenetriamine was added and reacted for 4 h to obtain an amino-terminated hyperbranched polymer N101.

[0108] (5) Add 600.0 g (4 mol) of 4-formylbenzoic acid to the above-mentioned terminal amino hyperbranching, stir and react at 25° C. for 1 h, and remove methanol by reduced pressure distillation at 40° C. to obtain a dynamic covalent hyperbranched terminal carboxyl polyester FANHBP-1. GPC test shows that its molecular weight is 898 g / mol and its acid value is 279.8 mgKOH / g.

[0109] (6) 300.0 g of VANEP, 21.0 g of VANEHBP and 188.0 g of FANHBP-1 were mixed uniformly to obtain a bio-based hyperbranched polymer epoxy resin.

[0110] The bio-based hyperbranched polymer epoxy resin was cured at 120°C for 2 h to obtain a recyclable epoxy resin material.

[0111] Preparation of epoxy resin material for remodeling and recycling: After the cured product of the recyclable bio-based hyperbranched polymer epoxy resin is crushed, hot pressing is performed at 120° C. and 5 MPa for 30 minutes to obtain epoxy resin for remodeling and recycling.

[0112] Preparation of epoxy resin material recovered by chemical degradation: 50.0g of the above epoxy resin cured product was immersed in 400.0g of 0.20mol / L HClN,N-dimethylformamide solution, heated at 70°C for degradation for 30min, and then the degradation solution was dried at 100°C for 2h to obtain the epoxy resin recovered by chemical degradation.

[0113] Example 2

[0114] (1) 456.0 g (3 mol) of vanillin and 440.0 g (1 mol) of trimethylolpropane tri[poly(propylene glycol)amine]ethyl ether were stirred in 3648.0 g of ethanol solution at 30° C. for 0.5 h.

[0115] (2) The product obtained above was mixed and dissolved with 2700.0g of epichlorohydrin, 9.12g of tetrabutylammonium bromide was added, and the mixture was stirred at 80°C for 4h, and then the epichlorohydrin was removed by vacuum distillation at 100°C. The product was dissolved in 6159.0g of ethyl acetate, and 2280.0g of 30wt.% sodium hydroxide aqueous solution was added during mechanical stirring and the reaction was continued for 6h in an ice bath. After the reaction was completed, the mixture was filtered, washed with water, and separated. The organic layer was dried with anhydrous sodium sulfate and then vacuum distilled to remove the organic solvent to obtain vanillin epoxy resin VANEP, with an epoxy value of 0.27mol / 100g.

[0116] (3) 3896.0 g (4 mol) of VANEP, 913.2 g (3 mol) of bisphenol A, 39.0 g of tetrabutylammonium bromide and 9120.0 g of tetrahydrofuran were stirred and reacted at 70° C. for 6 h to obtain a dynamic covalent hyperbranched epoxy resin VANEHBP. GPC test showed that its number average molecular weight was 4739 g / mol and the epoxy value was 0.13 mol / 100 g.

[0117] (4) 60.1 g (1 mol) of ethylenediamine and 516.5 g (6 mol) of methyl acrylate were stirred in an ice bath for 8 h, 189.8 g of methanol was added, the temperature was raised to 60° C., 673.1 g (6 mol) of diethylenetriamine was added, and the reaction was carried out for 6 h to obtain terminal amino hyperbranched N102.

[0118] (5) 1200.0 g (8 mol) of 4-formylbenzoic acid was added to the amino-terminated hyperbranched polyester obtained above, and the mixture was stirred at 25° C. for 2 h. Methanol was removed by distillation under reduced pressure at 40° C. to obtain a dynamic covalent hyperbranched carboxyl-terminated polyester FANHBP-2. The molecular weight was 2050 g / mol and the acid value was 218.9 mgKOH / g as measured by GPC.

[0119] (6) 300.0 g VANEP, 21.0 g VANEHBP and 214.6 g FANHBP-2 were mixed uniformly to obtain a bio-based hyperbranched polymer epoxy resin.

[0120] The bio-based hyperbranched polymer epoxy resin was cured at 120°C for 2 h to obtain a recyclable epoxy resin material.

[0121] Preparation of epoxy resin material for reshaping and recycling: the above-mentioned recyclable epoxy resin cured product is crushed and hot-pressed at 120° C. and 5 MPa for 30 minutes to obtain epoxy resin for reshaping and recycling.

[0122] Preparation of chemical degradation and recovery epoxy resin material: immerse 50.0g of the above epoxy resin cured product in 500.0g of 0.20mol / L HClN,N-dimethylformamide solution, heat and degrade at 65°C for 30min, and then dry the degradation solution at 100°C for 2h to obtain chemical degradation and recovery epoxy resin.

[0123] Example 3

[0124] (1) 456.0 g (3 mol) of vanillin and 146.2 g (1 mol) of tris(2-aminoethyl)amine were stirred in 2736.0 g of ethanol solution at 30° C. for 1 h.

[0125] (2) The product obtained above was mixed and dissolved with 1824.0g of epichlorohydrin, 9.12g of tetrabutylammonium bromide was added, and the mixture was stirred at 60°C for 6h, and then the epichlorohydrin was removed by vacuum distillation at 100°C. The product was dissolved in 4560.0g of ethyl acetate, and 2052.0g of 30wt.% sodium hydroxide aqueous solution was added during mechanical stirring, and the mixture was continued to react for 4h in an ice bath. After the reaction was completed, the mixture was filtered, washed with water, and separated. The organic layer was dried with anhydrous sodium sulfate, and then the organic solvent was removed by vacuum distillation to obtain vanillin epoxy resin (VANEP) with an epoxy value of 0.44mol / 100g.

[0126] (3) 2022.0 g (4 mol) of VANEP, 684.9 g (3 mol) of bisphenol A, 26.4 g of tetrabutylammonium bromide and 7920.0 g of tetrahydrofuran were stirred and reacted at 60° C. for 10 h to obtain a dynamic covalent hyperbranched epoxy resin VANEHBP. GPC test showed that its number average molecular weight was 3527.0 g / mol and the epoxy value was 0.17 mol / 100 g.

[0127] (4) 60.1 g (1 mol) of ethylenediamine and 516.5 g (6 mol) of methyl acrylate were stirred in an ice bath for 8 h, 189.8 g of methanol was added, the temperature was raised to 60° C., 673.1 g (6 mol) of diethylenetriamine was added, and the reaction was carried out for 6 h to obtain an amino-terminated hyperbranched polymer N102.

[0128] (5) 1200.0 g (8 mol) of 4-formylbenzoic acid was stirred and reacted in the above-obtained amino-terminated hyperbranched polyester for 2 h, and methanol was removed by vacuum distillation at 40° C. to obtain a dynamic covalent hyperbranched carboxyl-terminated polyester FANHBP-2. The molecular weight was 2050 g / mol and the acid value was 218.9 mgKOH / g as measured by GPC.

[0129] (6) 300.0 g VANEP, 21.0 g VANEHBP and 347.4 g FANHBP-2 were mixed uniformly to obtain a bio-based hyperbranched polymer epoxy resin.

[0130] The bio-based hyperbranched polymer epoxy resin was cured at 120°C for 2 h to obtain a recyclable epoxy resin.

[0131] Preparation of epoxy resin material for reshaping and recycling: the above-mentioned recyclable epoxy resin cured product is crushed and hot-pressed at 120° C. and 5 MPa for 30 minutes to obtain epoxy resin for reshaping and recycling.

[0132] Preparation of epoxy resin material recovered by chemical degradation: 50.0 g of the above epoxy resin cured product was immersed in 500.0 g of 0.20 mol / L HClN,N-dimethylformamide solution, heated at 65° C. for degradation for 30 min, and then the degradation solution was dried at 100° C. for 2 h to obtain the epoxy resin recovered by chemical degradation.

[0133] Example 4

[0134] (1) 456.0 g (3 mol) of vanillin and 126.1 g (1 mol) of melamine were stirred in 2736.0 g of ethanol solution at 30° C. for 1 h.

[0135] (2) The product obtained above was mixed and dissolved with 2280.0g of epichlorohydrin, 11.4g of tetrabutylammonium bromide was added, and the mixture was stirred at 100°C for 6h, and then the epichlorohydrin was removed by vacuum distillation at 100°C. The product was dissolved in 4560.0g of ethyl acetate, and 1915.2g of 40wt.% sodium hydroxide aqueous solution was added during mechanical stirring and the mixture was continued to react for 6h in an ice bath. After the reaction was completed, the mixture was filtered, washed with water, and separated. The organic layer was dried with anhydrous sodium sulfate and then vacuum distilled to remove the organic solvent to obtain vanillin epoxy resin (VANEP), with a yield of 90% and an epoxide value of 0.45mol / 100g.

[0136] (3) 2696.0 g (4 mol) of VANEP, 684.9 g (3 mol) of bisphenol A, 24.2 g of tetrabutylammonium bromide and 8088.0 g of tetrahydrofuran were stirred and reacted at 75° C. for 8 h to obtain a dynamic covalent hyperbranched epoxy resin VANEHBP. GPC test showed that its number average molecular weight was 3471.0 g / mol and the epoxy value was 0.17 mol / 100 g.

[0137] (4) 60.1 g (1 mol) of ethylenediamine and 516.5 g (6 mol) of methyl acrylate were stirred in an ice bath for 8 h, 189.8 g of methanol was added, the temperature was raised to 60° C., 673.1 g (6 mol) of diethylenetriamine was added, and the reaction was carried out for 6 h to obtain an amino-terminated hyperbranched polymer (N102).

[0138] (5) 1200.0 g (8 mol) of 4-formylbenzoic acid was stirred and reacted in the above-obtained amino-terminated hyperbranched polyester for 2 h, and methanol was removed by vacuum distillation at 40° C. to obtain a dynamic covalent hyperbranched carboxyl-terminated polyester (FANHBP-2). The molecular weight was 2050 g / mol and the acid value was 218.9 mgKOH / g as measured by GPC.

[0139] (6) 300.0 g VANEP, 21.0 g VANEHBP and 355.1 g FANHBP-2 were mixed uniformly to obtain a bio-based hyperbranched polymer epoxy resin.

[0140] The bio-based hyperbranched polymer epoxy resin was cured at 120°C for 2 h to obtain a recyclable epoxy resin material.

[0141] Preparation of epoxy resin material for reshaping and recycling: the above-mentioned recyclable epoxy resin cured product is crushed and hot-pressed at 120° C. and 5 MPa for 30 minutes to obtain epoxy resin for reshaping and recycling.

[0142] Preparation of epoxy resin material recovered by chemical degradation: 50.0 g of the above epoxy resin cured product was immersed in 500.0 g of 0.20 mol / L HCl aqueous solution, heated at 70° C. for 60 min, and then the degradation solution was dried at 100° C. for 2 h to obtain the epoxy resin recovered by chemical degradation.

[0143] Preparation of recyclable carbon fiber composite materials: 150.0 g of carbon fiber cloth was fully impregnated with bio-based hyperbranched polymer epoxy resin (a mixture of 55.0 g VANEP, 3.9 g VANEHBP, and 65.1 g FANHBP-2), and the carbon fiber cloth prepreg was obtained after being taken out and dried at 50°C for 3 h. Eight layers of the prepared carbon fiber cloth prepreg were stacked together and placed in a mold. The prepreg was hot-pressed at 120°C and 10 MPa for 30 min, and then post-cured at 120°C for 2 h. The prepreg was naturally cooled and taken out to obtain a recyclable epoxy resin carbon fiber composite material.

[0144] Preparation of recycled carbon fiber composite material: 10mm×10mm×2mm recyclable epoxy resin carbon fiber composite material was immersed in 0.2mol / L HCl N,N-dimethylformamide solution and degraded at 65℃ for 60min, and the carbon fiber cloth obtained by degradation was dried at 80℃ for 6h to obtain regenerated carbon fiber cloth. The degradation liquid obtained by degradation was evaporated to remove HCl N,N-dimethylformamide solution to obtain oligomers, and the obtained oligomers were fully impregnated with recycled carbon fiber cloth, and then dried at 50℃ for 3h to obtain recycled carbon fiber prepreg. 8 layers of the above recycled carbon fiber cloth prepreg were stacked together and put into a mold, and hot pressed at 120℃ and 10MPa for 30min, and then post-cured at 120℃ for 2h, and taken out after natural cooling to obtain recycled epoxy resin carbon fiber composite material.

[0145] Example 5

[0146] (1) 456.0 g (3 mol) of vanillin and 126.1 g (1 mol) of melamine were stirred in 2736.0 g of ethanol solution at 30° C. for 1 h.

[0147] (2) The product obtained above was mixed and dissolved with 2280.0g of epichlorohydrin, 11.4g of tetrabutylammonium bromide was added, and the mixture was stirred at 100°C for 6h, and then the epichlorohydrin was removed by vacuum distillation at 100°C. The product was dissolved in 4560.0g of ethyl acetate, and 1915.2g of 40wt.% sodium hydroxide aqueous solution was added during mechanical stirring and the reaction was continued in an ice bath for 6h. After the reaction was completed, the mixture was filtered, washed with water, and separated. The organic layer was dried with anhydrous sodium sulfate and then vacuum distilled to remove the organic solvent to obtain vanillin epoxy resin (VANEP) with an epoxide value of 0.45mol / 100g.

[0148] (3) 2696.0 g of VANEP (4 mol), 684.9 g (3 mol) of bisphenol A, 24.2 g of tetrabutylammonium bromide and 8088.0 g of tetrahydrofuran were stirred and reacted at 75° C. for 8 h to obtain a dynamic covalent hyperbranched epoxy resin VANEHBP. GPC test showed that its number average molecular weight was 3471.0 g / mol and the epoxy value was 0.17 mol / 100 g.

[0149] (4) 60.1 g (1 mol) of ethylenediamine and 1205.3 g (14 mol) of methyl acrylate were stirred in an ice bath for 8 h, 284.8 g of methanol was added, the temperature was raised to 60° C., 1570.5 g (14 mol) of diethylenetriamine was added, and the reaction was carried out for 6 h to obtain an amino-terminated hyperbranched polymer N103.

[0150] (5) 2400.0 g (16 mol) of 4-formylbenzoic acid was stirred and reacted in the above-obtained amino-terminated hyperbranched polyester for 2 h, and methanol was removed by vacuum distillation at 40° C. to obtain a dynamic covalent hyperbranched carboxyl-terminated polyester FANHBP-3. The molecular weight was 4354 g / mol and the acid value was 206.2 mgKOH / g by GPC.

[0151] 50.0g VANEP, 3.5g VANEHBP and 62.5g FANHBP-3 were mixed evenly to obtain a bio-based hyperbranched polymer epoxy resin, and 150.0g carbon fiber cloth was fully impregnated with the bio-based hyperbranched polymer epoxy resin. After taking out, it was dried at 50°C for 3h to obtain a carbon fiber cloth prepreg. 8 layers of the prepared carbon fiber cloth prepreg were stacked together and put into a mold, and hot pressed at 120°C and 10MPa for 30min, and then post-cured at 120°C for 2h, and taken out after natural cooling to obtain a recyclable epoxy resin carbon fiber composite material.

[0152] (7) A 10 mm × 10 mm × 2 mm recyclable epoxy resin carbon fiber composite material was immersed in a 0.2 mol / L HCl N, N-dimethylformamide solution and degraded at 65°C for 60 min. The carbon fiber cloth obtained by degradation was dried at 80°C for 6 h to obtain a regenerated carbon fiber cloth. The degradation liquid obtained by degradation was evaporated to remove the HCl N, N-dimethylformamide solution to obtain an oligomer, and the obtained oligomer was fully impregnated with the regenerated carbon fiber cloth, and then dried at 50°C for 3 h to obtain a regenerated carbon fiber prepreg. 8 layers of the above regenerated carbon fiber cloth prepreg were stacked together and put into a mold, and hot pressed at 120°C and 10 MPa for 30 min, and then post-cured at 120°C for 2 h, and taken out after natural cooling to obtain a recycled epoxy resin carbon fiber composite material.

[0153] Comparative Example 1

[0154] (1) 456.0 g (3 mol) of vanillin and 126.1 g (1 mol) of melamine were stirred in 2736.0 g of ethanol solution at 30° C. for 1 h.

[0155] (2) The product obtained above was mixed and dissolved with 2280.0g of epichlorohydrin, 11.4g of tetrabutylammonium bromide was added, and the mixture was stirred at 100°C for 6h, and then the epichlorohydrin was removed by vacuum distillation at 100°C. The product was dissolved in 4560.0g of ethyl acetate, and 1915.2g of 40wt.% sodium hydroxide aqueous solution was added during mechanical stirring and the reaction was continued for 6h in an ice bath. After the reaction was completed, the mixture was filtered, washed with water, and separated. The organic layer was dried with anhydrous sodium sulfate and then vacuum distilled to remove ethyl acetate to obtain vanillin epoxy resin VANEP, with a yield of 90% and an epoxide value of 0.45mol / 100g.

[0156] (3) 60.1 g (1 mol) of ethylenediamine and 1205.3 g (14 mol) of methyl acrylate were stirred in an ice bath for 8 h, 284.8 g of methanol was added, the temperature was raised to 60° C., 1570.5 g (14 mol) of diethylenetriamine was added, and the reaction was carried out for 6 h to obtain an amino-terminated hyperbranched polymer N103.

[0157] (4) 2400.0 g (16 mol) of 4-formylbenzoic acid was stirred and reacted in the above-obtained amino-terminated hyperbranched polyester for 2 h, and the methanol was removed by vacuum distillation at 40° C. to obtain a dynamic covalent hyperbranched carboxyl-terminated polyester (FANHBP-3). The molecular weight was 4354 g / mol and the acid value was 206.2 mgKOH / g by GPC test.

[0158] 150.0 g of carbon fiber cloth was fully impregnated with a mixture of 50.0 g of VANEP and 61.2 g of FANHBP-3, and the prepreg was obtained by drying at 50 ° C for 3 h. Eight layers of the prepared carbon fiber cloth prepreg were stacked together and put into a mold. They were hot-pressed at 120 ° C and 10 MPa for 30 min, and then post-cured at 120 ° C for 2 h. After natural cooling, they were taken out to obtain a recyclable epoxy resin carbon fiber composite material.

[0159] The 10mm×10mm×2mm recyclable epoxy resin carbon fiber composite material was immersed in 0.2mol / L HClN,N-dimethylformamide solution and degraded at 65℃ for 60min. The carbon fiber cloth obtained by degradation was dried at 80℃ for 6h to obtain the regenerated carbon fiber cloth. The degradation liquid obtained by degradation was evaporated to remove the HClN,N-dimethylformamide solution to obtain oligomers, and the obtained oligomers were fully impregnated with the regenerated carbon fiber cloth, and then dried at 50℃ for 3h to obtain the regenerated carbon fiber prepreg. 8 layers of the above regenerated carbon fiber cloth prepreg were stacked together and put into the mold, and hot pressed at 120℃ and 10MPa for 30min, and then post-cured at 120℃ for 2h, and taken out after natural cooling to obtain the recycled epoxy resin carbon fiber composite material.

[0160] Comparative Example 2

[0161] 300.0 g of DGEBA and 90.5 g of FANHBP-2 were mixed evenly and then cured at 120° C. for 2 h to obtain an epoxy resin material.

[0162] The epoxy resin and carbon fiber composite materials obtained in Examples 1 to 7 of this specific implementation method were placed at 25°C for 24 hours, and the tensile properties were measured according to ASTM 3039, the unnotched impact strength was measured according to ASTM D256, the fracture toughness of the material was measured according to ASTM D5045, and the glass transition temperature was measured according to ASTM_D2863. The relaxation time was tested using the tensile mode of DMA Q800. The sample maintained a 1% tensile deformation at 130°C, and the time when the stress relaxed to 1 / e was recorded as the relaxation time of the sample at 130°C.

[0163] The performance indicators of the epoxy resins obtained in each embodiment are shown in Table 1, Table 2, Table 3 and Table 4.

[0164] Table 1 Properties of all bio-based epoxy resins obtained in Examples 1 to 4

[0165] performance Example 1 Example 2 Example 3 Example 4 Comparative Example 2 Tensile strength, MPa 103 107 94 100 70 <![CDATA[Impact strength, kJ / m 2 > 22.5 30.4 24.6 25.5 10.5 Glass transition temperature, °C 110 115 116 118 75 Creep resistance temperature 100 100 100 100 80 Relaxation time at 130℃, s 12 10 12 13 -

[0166] Table 2 Properties of the recyclable epoxy resin carbon fiber composite materials obtained in Examples 4, 5 and Comparative Example 1

[0167] performance Example 4 Example 5 Comparative Example 1 Tensile strength, MPa 650 720 540 <![CDATA[Impact strength, kJ / m 2 > 102 158 74 Glass transition temperature, °C 110 130 100

[0168] Table 3 Properties of recyclable epoxy resin and carbon fiber composite materials of Examples 1 to 5 and Comparative Example 1

[0169]

[0170]

[0171] Table 4 Properties of epoxy resins obtained by reshaping processes of Examples 1 to 4

[0172]

[0173]

[0174] As can be seen from Tables 1, 2, 3 and 4 above, the bio-based hyperbranched polymer epoxy resin of the present invention has excellent mechanical properties, glass transition temperature and creep resistance temperature, and is expected to replace traditional petroleum-based epoxy resins in adhesives, carbon fiber composites and high-temperature wind power insulation materials. The dynamic covalent hyperbranched carboxyl-terminated polyester used in its preparation process enables the bisphenol A epoxy resin to be degraded and repeatedly processed after being cured and formed. The recyclable epoxy resin and recyclable carbon fiber composite material provided by the present invention have a simple preparation process, excellent mechanical properties, heat resistance, solvent resistance, hydrolysis resistance, creep resistance and corrosion resistance, are suitable for large-scale industrial production, and can be used in wind turbine blades, lightweight automotive materials, hydrogen energy and hydrogen storage bottles for fuel cells and other fields.

[0175] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a bio-based hyperbranched polymer epoxy resin, characterized in that: A linear vanillin epoxy resin, a dynamic covalent vanillin hyperbranched epoxy resin and a dynamic covalent hyperbranched carboxyl-terminated polyester are prepared respectively, and then the three are dynamically cross-linked and mixed to obtain a bio-based hyperbranched polymer epoxy resin; The mass ratio of the linear vanillin epoxy resin, the dynamic covalent bond vanillin hyperbranched epoxy resin and the dynamic covalent bond hyperbranched carboxyl-terminated polyester is 1:0.07:(0.63-1.18); The preparation method of the dynamic covalent bond hyperbranched carboxyl-terminated polyester comprises the following steps: S3-1, stirring ethylenediamine and methyl acrylate in an ice bath for 8 to 10 hours, then adding a fourth organic solvent, heating to 60 to 80° C., adding diethylenetriamine and reacting for 4 to 6 hours to obtain an amino-terminated hyperbranched polymer; The mass ratio of the ethylenediamine, methyl acrylate, diethylenetriamine and the fourth organic solvent is 1.0:(2.8-20.0):(3.7-26.1):(1.6-5.0); S3-2, adding 4-formylbenzoic acid to the amino-terminated hyperbranched polymer, stirring and reacting for 0.5 to 2 hours to obtain the dynamic covalent hyperbranched carboxyl-terminated polyester; The mass ratio of the amino-terminated hyperbranched polymer to the 4-formylbenzoic acid is 1.0:(0.55-0.67).

2. A method for preparing a bio-based hyperbranched polymer epoxy resin according to claim 1, characterized in that: The preparation method of the linear vanillin epoxy resin comprises the following steps: S1-1, mixing vanillin and a triamine compound in a first organic solvent and reacting them at a reaction temperature of 20 to 40° C. for a reaction time of 0.5 to 2 h; S1-2, mixing the product obtained in step S1-1 with epichlorohydrin, adding a catalyst, and reacting at 60-80° C. for 4-6 hours; S1-3, adding a second organic solvent and a sodium hydroxide aqueous solution to the product obtained in step S1-2, and continuing the reaction at 0-10° C. for 4-6 hours; S1-4, after the reaction of step S1-3 is completed, the obtained product is sequentially washed with water, separated, and distilled under reduced pressure to obtain the linear vanillin epoxy resin; The mass ratio of the vanillin, the triamine compound, the epichlorohydrin, the catalyst, the sodium hydroxide aqueous solution, the first organic solvent, and the second organic solvent is 1.0: 0.28-1.0: (4.0-6.0): (0.02-0.03): (4.1-5.0): (6-8): (10-13.5); wherein, in the sodium hydroxide aqueous solution, the mass of sodium hydroxide accounts for 10% to 40% of the total mass of the solution.

3. A method for preparing a bio-based hyperbranched polymer epoxy resin according to claim 2, characterized in that: In the step S1-1, the first organic solvent is ethanol or methanol; the triamine compound is one or more of trimethylolpropane tris[poly(propylene glycol)amine]ethyl ether, melamine and tris(2-aminoethyl)amine; the second organic solvent is one of ethylene glycol, methyl ether, cyclohexanone, n-butanol, tetrahydrofuran, ethyl acetate and dichloromethane; In the step S1-2, the catalyst is one of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, and trioctylmethylammonium chloride.

4. The method for preparing a bio-based hyperbranched polymer epoxy resin according to claim 1, characterized in that: The preparation method of the dynamic covalent bond vanillin hyperbranched epoxy resin comprises the following steps: S2, stirring the linear vanillin epoxy resin, the dihydroxy monomer, the catalyst and the third organic solvent at 60 to 80° C. for 4 to 12 hours to obtain the dynamic covalent bond vanillin hyperbranched epoxy resin; The mass ratio of the linear vanillin epoxy resin, the dihydroxy monomer, the catalyst and the third organic solvent is 1.0:(0.23-0.34):(0.009-0.01):(2.34-4.0); The dihydroxy monomer in step S2 is one of bisphenol A, bisphenol F, and hydroquinone; the third organic solvent is tetrahydrofuran or dichloromethane; the catalyst is one of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, and trioctylmethylammonium chloride.

5. A method for preparing a bio-based hyperbranched polymer epoxy resin according to claim 4, characterized in that: The chemical structure of the dynamic covalent vanillin hyperbranched epoxy resin is shown in general formula (1), general formula (2) or general formula (3): Among them, R1 is expressed as Or general formula (4): In the structural formula of R1, * indicates the position of connection with R2; in the general formula (4), x+y+z=5-6; R2 is expressed as In the structural formula of R2, * indicates the position of connection to R1, and ** indicates the position of connection to R3 or location; R3 is expressed as Wherein, *** indicates the position connected to R2.

6. The method for preparing a bio-based hyperbranched polymer epoxy resin according to claim 1, characterized in that: The chemical structure of the dynamic covalent hyperbranched carboxyl-terminated polyester is as described in general formula (5), general formula (6) or general formula (7): Among them, R4 is represented by Wherein, * indicates the position connected to R5 or R7; R5 is expressed as Wherein, ** indicates the position connected to R4 or R7, and *** indicates the position connected to R6; R6 is represented by Wherein, **** indicates the position connected to R5, ***** indicates the position connected to -COOH; R7 is represented by: Among them, **** indicates the position connected to R5 or R7, and ****** indicates the position connected to R4.

7. The method for preparing a bio-based hyperbranched polymer epoxy resin according to any one of claims 1 to 6, characterized in that: The three are then dynamically cross-linked and mixed, comprising the following steps: S4, mixing the linear vanillin epoxy resin, the dynamic covalent bond vanillin hyperbranched epoxy resin and the dynamic covalent bond hyperbranched carboxyl-terminated polyester and stirring them uniformly.

8. A bio-based hyperbranched polymer epoxy resin, characterized in that: The preparation method is as described in any one of claims 1 to 7.

9. The use of the bio-based hyperbranched polymer epoxy resin according to claim 8, characterized in that: It can be applied to wind turbine blades, lightweight automotive materials, or hydrogen storage bottles for hydrogen fuel cells.

10. A recyclable epoxy resin, characterized in that: It is prepared using the bio-based hyperbranched polymer epoxy resin described in claim 8.

11. A method for preparing a recyclable epoxy resin as claimed in claim 10, characterized in that: The bio-based hyperbranched polymer epoxy resin is poured into a mold and cured at 80° C.-120° C. for 1 to 4 hours to obtain the recyclable epoxy resin.

12. A recyclable carbon fiber composite material, characterized in that: It is prepared using the bio-based hyperbranched polymer epoxy resin described in claim 8.

13. A method for preparing a recyclable carbon fiber composite material according to claim 12, characterized in that: The following steps are involved: The carbon fiber cloth is fully impregnated with the bio-based hyperbranched polymer epoxy resin; after impregnation, the carbon fiber cloth is taken out and dried at 40 to 60° C. for 2 to 3 hours to obtain a carbon fiber cloth prepreg; 7 to 8 layers of the carbon fiber cloth prepreg are stacked and placed in a mold, hot-pressed at 100 to 120° C. and 10 to 15 MPa for 30 to 60 minutes, then cured at 100 to 120° C. for 2 to 4 hours, and taken out after natural cooling to obtain the recyclable carbon fiber composite material.

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