A bio-based hyperbranched epoxy resin / bisphenol a epoxy resin composite resin containing imide structure

Abstract

The application discloses a kind of bio-based hyperbranched epoxy resin / Bisphenol A type epoxy resin composite resin containing imide structure.Preparation process: (1) the reaction of hydroxyl amine, aldehyde compound and mercapto carboxylic acid obtains mercapto compound A3) ;(2) N-phenyl maleimide, 2,5-furan dimethylamine and mercaptan are synthesized by thiol-olefin click reaction Diamino compound, again with maleic anhydride and carry out imidization reaction, synthesis bio-based maleimide (B2) ;(3) A3 and B2 are synthesized by click reaction end mercapto hyperbranched polymer, again with alkenyl epoxy compound and generate bio-based hyperbranched epoxy resin by click reaction;(4) Bisphenol A type epoxy resin is blended with it and cured, and bio-based hyperbranched epoxy resin / Bisphenol A type epoxy resin composite resin containing imide structure is obtained.The material prepared in the application is environment-friendly and sustainable production, and can be applied to aerospace, turbine technology and other frontier fields.

Description

Technical Field

[0001] This invention belongs to the field of biodegradable hyperbranched epoxy resin technology, specifically relating to a bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure. Background Technology

[0002] Epoxy resins (EP) are an important class of thermosetting resins. Their highly cross-linked structure after curing gives them excellent dimensional stability, heat resistance, and superior mechanical properties, making them widely used in cutting-edge fields such as aerospace, turbine technology, maritime transport, and electronics. However, the raw materials for traditional epoxy resin synthesis mainly come from non-renewable resources such as petroleum, which hinders the sustainable development of the epoxy resin industry. Therefore, developing bio-based epoxy resins based on renewable resources is crucial for sustainable production and environmentally friendly high-performance materials.

[0003] In recent years, an increasing number of studies have focused on developing novel epoxy materials to overcome the trade-off between toughness and strength and to address the energy and environmental problems caused by plastic waste. Bio-based hyperbranched epoxy resins synthesized from biological monomers can be used as matrix resins or toughening agents, thus forming partially or fully bio-based epoxy thermosetting plastics. Introducing hyperbranched structures can balance the strength, toughness, degradability, and recyclability of epoxy thermosetting plastics. From a molecular design perspective, dynamic covalent bonds are introduced to design and prepare epoxy resins containing imide and triazine backbones, which can strengthen and toughen traditional bisphenol A type epoxy resins. The hexahydrotriazine structure exhibits good degradability under acidic conditions, enabling the recycling of epoxy resins. Furthermore, the introduction of imide structures into hyperbranched epoxy resins can achieve higher strength and expand the application of epoxy resins in high-end fields.

[0004] The raw materials for traditional epoxy resin synthesis mainly come from non-renewable resources such as petroleum, which hinders the sustainable development of the epoxy resin industry. The development of bio-based hyperbranched resins not only aligns with the principles of sustainable development and a circular economy but also considers the resin's biodegradability, recyclability, thermal stability, mechanical properties, and other functionalities. Therefore, developing composite resin preparation technologies for imide-containing bio-based hyperbranched epoxy resins / bisphenol A type epoxy resins is a fundamental way to solve the current problems in this field. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method.

[0006] The present invention solves the above-mentioned technical problems by means of the following technical solution:

[0007] One of the technical solutions: a bio-based hyperbranched epoxy resin containing an imide structure, the structural formula of which is shown in the following general formula (1):

[0008]

[0009] In this structure, R is a pyridine ring, and the -CH2O- group connected to R is located at at least one of the ortho, meta, and para positions of the pyridine ring.

[0010] Wherein, R1 has the following structure:

[0011] n is a natural number from 1 to 5

[0012] In this process, -CO- in mercaptocarboxylic acid reacts with -OH in hydroxyamine to form -COO-, and thiols in mercaptocarboxylic acid and olefins in olefin compounds form -CS- through a thiols-olefin click reaction, which is then linked to one or more of R', R”, and R”'.

[0013] Where R', R”, and R”' are the same or different, and are independently represented by the structure of general formula (2), general formula (3), or general formula (4):

[0014]

[0015] General formula (2) General formula (3) General formula (4);

[0016] Where X can be one or more of the following structures:

[0017]

[0018] R2 has the following structure:

[0019]

[0020] R3 has the following structure:

[0021]

[0022] R4 is an aliphatic alkane group with 4-18 carbon atoms -C4H. 9～ -C 18 H 37、 One or more of the aromatic hydrocarbon group -C6H5 and aromatic heterocyclic group -C5H4N structures.

[0023] The imide-containing bio-based hyperbranched epoxy resin has a number-average molecular weight of 4000–14000 g / mol and an epoxy value of 0.08–0.14 mol / 100g.

[0024] Technical Solution Two: A method for preparing an imide-based bio-based hyperbranched epoxy resin, comprising the following steps:

[0025] (1) Add hydroxyl amino compounds, aldehyde compounds and anhydrous ethanol to a reaction flask and stir the reaction at 65-95℃ for 4-7 hours to obtain a terminal hydroxyl compound. Then add mercaptocarboxylic acid, catalyst and organic solvent to the reaction flask and stir the reaction at 20-30℃ for 10-15 hours. Remove the solvent by rotary evaporation to obtain mercapto compound (A3).

[0026] (2) Add N-phenylmaleimide, 2,5-furandimethylamine, thiol and organic solvent to a reaction flask, stir and react at 75-105℃ for 10-15 hours to obtain a diamino compound. Then add maleic anhydride to the reaction flask, stir and react at 60-170℃ for 10-14 hours, remove the solvent by rotary evaporation to obtain bio-based maleimide (B2).

[0027] (3) The thiol compound (A3) obtained in step (1), the bio-based maleimide (B2) obtained in step (2), the photoinitiator and the organic solvent are added to the reaction flask and the thiol-olefin click reaction is carried out by irradiation with ultraviolet light of 400W-800W for 20-60 minutes to obtain the bio-based end-thiol hyperbranched polymer. Then, an alkenyl epoxy compound is added to the reaction flask and the thiol-olefin click reaction is carried out by irradiation with ultraviolet light of 400W-800W for 60-100 minutes. The solvent is removed by rotary evaporation to obtain the bio-based hyperbranched epoxy resin containing the imide structure, with a number average molecular weight of 4000-14000 g / mol and an epoxy value of 0.08-0.14 mol / 100g.

[0028] Further, the hydroxylamine is one or more selected from 3-amino-4-hydroxymethylpyridine, 2-amino-3-hydroxymethylpyridine, and 2-(hydroxymethyl)-5-aminopyridine; the aldehyde compound is one or more selected from formaldehyde aqueous solution, paraformaldehyde, and paraformaldehyde; and the thiocarboxylic acid is... n = 1 to 5, preferably one or both of mercaptopropionic acid (MPA) and mercaptoacetic acid (TGA); the thiol is C4H9-SH ～ C 18 H 37 One or more of -SH, phenylthiols, and pyridinethiols, preferably C4H9-SH ～ C 14 H 29One or more of -SH, phenylthiol and 4-pyridinethiol, more preferably one or more of butanethiol, phenylthiol and 4-pyridinethiol; the alkenyl epoxy compound is one or more of allyl glycidyl ether, 2,3-epoxypropyl acrylate and 1,2-epoxy-5-hexene.

[0029] Furthermore, the organic solvents in steps (1), (2), and (3) may be the same or different, and each may be one or more of tetrahydrofuran, 1,4-dioxane, acetone, and N,N-dimethylformamide; the catalyst may be one or more of 4-dimethylaminopyridine, p-toluenesulfonic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and stannous oxalate; and the photoinitiator may be one or more of benzophenone, p-aminoacetone, 2,2-dimethoxy-2-phenylacetophenone, and 1-hydroxycyclohexylphenyl ketone.

[0030] Furthermore, in step (1), the molar ratio of hydroxylamine to aldehyde is 1:(1.1-1.5), the mass ratio of hydroxylamine to anhydrous ethanol is 1:5, the molar ratio of hydroxylamine to mercaptocarboxylic acid is 1:(1.1-1.25), and the mass of the catalyst is 10%-20% of the mass of hydroxylamine.

[0031] In step (2), the molar ratio of N-phenylmaleimide, 2,5-furandimethylamine and thiol is 1:(1.5~2.22):1, and the molar ratio of N-phenylmaleimide to maleic anhydride is 1:(2.0~2.4).

[0032] In steps (1), (2) and (3), the mass of organic solvent added is 1-10 times the total mass of monomers added in that step;

[0033] In step (3), the molar ratio of thiol compound (A3) to bio-based maleimide (B2) is 1:(0.75-0.9), the molar ratio of thiol compound (A3) to photoinitiator is 1:(0.1-1.14), and the molar ratio of thiol compound (A3) to alkenyl epoxy compound is 1:(1.28-1.72).

[0034] Technical Solution 3: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure, wherein the composite resin comprises the above-mentioned bio-based hyperbranched epoxy resin containing an imide structure or the bio-based hyperbranched epoxy resin containing an imide structure prepared by the above method and a bisphenol A type epoxy resin. The preparation steps of the composite resin include: mixing the bio-based hyperbranched epoxy resin containing an imide structure, the bisphenol A type epoxy resin and a curing agent evenly, pouring the mixture into a mold and heat curing it to obtain the composite resin; the heat curing temperature is 60-170℃, and the heat curing time is 3-15 hours; the curing agent is one or more of 4,4'-diaminodiphenyl sulfone, 2,5-furan dimethylamine and 4,4'-diaminodiphenylmethane.

[0035] Furthermore, the bisphenol A type epoxy resin is designated as E51.

[0036] Furthermore, the mass ratio of the imide-containing bio-based hyperbranched epoxy resin, bisphenol A type epoxy resin and curing agent is 1:(5.67-15.67):(1.45-4.83), preferably 1:(5.67-7.33):(1.45-4.56).

[0037] Furthermore, the thermosetting conditions are as follows: cure at 60-70℃ for 2 hours, at 90-100℃ for 2-3 hours, at 120-130℃ for 2-3 hours, and at 140-170℃ for 1-2 hours.

[0038] Technical Solution 4: Application of bio-based hyperbranched epoxy resins containing imide structures in the reinforcement and toughening of linear epoxy resins.

[0039] The advantages of this invention are:

[0040] (1) The present invention prepares bio-based hyperbranched epoxy resin by click reaction, and the preparation method has high selectivity, high yield and high efficiency.

[0041] (2) The hydroxylamine and 2,5-furandimethylamine used in this invention are mainly derived from carbohydrate bio-based raw materials such as cellulose / starch. They are widely available, green and environmentally friendly, and in line with the concept of sustainable development.

[0042] (3) The present invention achieves reinforcement and toughening of bisphenol A type epoxy resin by introducing an imide ring and a hexahydrotriazine structure into the structure of hyperbranched epoxy resin.

[0043] (4) The present invention obtains a bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure. Compared with bio-based epoxy resin, the introduction of hyperbranched topology effectively improves the mechanical properties of the composite resin and obtains a high-strength composite resin.

[0044] (5) In this invention, the imide-structured bio-based hyperbranched epoxy resin is blended with bisphenol A type epoxy resin with a linear structure, which increases the polarity of the system, improves the compatibility, and effectively improves the mechanical properties of the composite material.

[0045] (6) The preparation method of the imide-structured bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin of the present invention is simple, the reaction conditions are mild, the reaction time is short, it is green and environmentally friendly, and it is suitable for industrial production. Attached Figure Description

[0046] Figure 1 The infrared characterization image is of the imide-containing bio-based hyperbranched epoxy resin (TMEP-12) prepared in Example 1.

[0047] Located at 2572cm -1 The -SH absorption vibration peak in the epoxy resin disappears; it is located at 913 cm⁻¹. -1 A new infrared characteristic peak appeared, which is the bending vibration peak of the epoxy group. Detailed Implementation

[0048] The method of the present invention will be further described below with reference to specific embodiments, but these embodiments should not limit the scope of protection of the present invention in any way.

[0049] The bisphenol A type epoxy resin used is E51.

[0050] The mass concentration of the formaldehyde aqueous solution used was 35 wt%; the degree of polymerization n of the paraformaldehyde used was 3.

[0051] Example 1: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0052] 6 g (0.048 mol) of 3-amino-4-hydroxymethylpyridine, 4.56 g (0.053 mol) of formaldehyde aqueous solution and 30 g of anhydrous ethanol were added to a reaction flask and stirred at 65 °C for 7 hours to obtain 6.58 g (0.016 mol) of hydroxyl-terminated compound. Then, 5.642 g (0.0528 mol) of MPA, 1.12 g of stannous oxalate catalyst and 32.9 g of acetone were added to the reaction flask and stirred at 25 °C for 10 hours. The solvent was removed by rotary evaporation to obtain the mercapto compound (A3). 4 g (0.023 mol) of N-phenylmaleimide, 4.37 g (0.035 mol) of 2,5-furandimethylamine, 5.30 g (0.023 mol) of tetradecyl mercaptan, and 20 g of N,N-dimethylformamide were added to a reaction flask and stirred at 100 °C for 15 hours to obtain a diamino compound. Then, 9.02 g (0.046 mol) of maleic anhydride was added to the reaction flask and stirred at 160 °C for 13 hours. The solvent was removed by rotary evaporation to obtain bio-based maleimide (B2). 4.68 g (0.007 mol) of thiol compound (A3), 4.14 g (0.006 mol) of bio-based maleimide (B2), 0.164 g (0.9 mmol) of benzophenone, and 20 g of N,N-dimethylformamide were added to a reaction flask and irradiated with 650 W UV light for 60 minutes to carry out a thiol-olefin click reaction, synthesizing 8.098 g (0.7 mmol) of bio-based end-thiol hyperbranched polymer. 1.03 g (0.009 mol) of allyl glycidyl ether was added to the mixed solution after the click reaction, and irradiated with 400 W UV light for 80 minutes. The solvent was removed by rotary evaporation to synthesize a bio-based hyperbranched epoxy resin (TMEP-12) containing an imide structure.

[0053] 3.6 g of imide-containing bio-based hyperbranched epoxy resin (TMEP-12), 10.28 g of 4,4'-diaminodiphenyl sulfone, and 26.4 g of bisphenol A type epoxy resin were blended, cast into specimens, and cured under the following conditions: 60℃ for 2 hours, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin was obtained, and its mechanical properties are shown in Table 2.

[0054] Example 2: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0055] 3.6 g of the imide-containing bio-based hyperbranched epoxy resin (TMEP-12) and 8.20 g of 4,4'-diaminodiphenylmethane prepared in Example 1 were blended with 26.4 g of bisphenol A type epoxy resin, and the mixture was cast into a sample and cured under the following conditions: 60°C for 2 hours, 90°C for 2 hours, 130°C for 3 hours, and 160°C for 2 hours. After curing, the sample was removed to obtain the imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin. Its mechanical properties are shown in Table 2.

[0056] Example 3: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0057] 3.6 g of the imide-containing bio-based hyperbranched epoxy resin (TMEP-12) and 5.22 g of 2,5-furandimethylamine prepared in Example 1 were blended with 26.4 g of bisphenol A type epoxy resin, and the mixture was cast into a sample for curing. The curing conditions were as follows: 60°C for 2 hours, 90°C for 2 hours, 130°C for 3 hours, and 160°C for 2 hours. After curing, the sample was removed to obtain the imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin. Its mechanical properties are shown in Table 2.

[0058] Example 4: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0059] 6 g (0.048 mol) of 2-hydroxymethyl-5-aminopyridine, 6.22 g (0.072 mol) of formaldehyde aqueous solution and 30 g of anhydrous ethanol were added to a reaction flask and stirred at 95 °C for 4 hours to obtain 6.58 g (0.016 mol) of hydroxyl-terminated compound; then 6.41 g (0.06 mol) of MPA, 0.650 g of 4-dimethylaminopyridine catalyst and 32.9 g of acetone were added to the reaction flask and stirred at 25 °C for 10 hours. The solvent was removed by rotary evaporation to obtain the mercapto compound (A3). 4 g (0.023 mol) of N-phenylmaleimide, 6.41 g (0.051 mol) of 2,5-furandimethylamine, 2.07 g (0.023 mol) of butanethiol and 20 g of N,N-dimethylformamide were added to a reaction flask and stirred at 75 °C for 10 hours to obtain a diamino compound. Then, 12.99 g (0.0552 mol) of maleic anhydride was added to the reaction flask and stirred at 135 °C for 10 hours. The solvent was removed by rotary evaporation to obtain bio-based maleimide (B2). 4.68 g (0.007 mol) of thiol compound (A3), 3.52 g (0.006 mol) of bio-based maleimide (B2), 0.164 g (0.8 mmol) of 1-hydroxycyclohexylphenyl ketone, and 20 g of N,N-dimethylformamide were added to a reaction flask and irradiated with 650 W UV light for 60 minutes to carry out a thiol-olefin click reaction, synthesizing 8.10 g (0.7 mmol) of bio-based end-thiol hyperbranched polymer. 1.03 g (0.009 mol) of allyl glycidyl ether was added to the mixed solution after the click reaction, and irradiated with 800 W UV light for 60 minutes. The solvent was removed by rotary evaporation to synthesize a bio-based hyperbranched epoxy resin (BMEP-12) containing an imide structure.

[0060] 3.6 g of imide-containing bio-based hyperbranched epoxy resin (BMEP-12), 8.22 g of 4,4'-diaminodiphenylmethane, and 26.4 g of bisphenol A type epoxy resin were blended, cast into specimens, and cured under the following conditions: 60℃ for 2 hours, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin was obtained, and its mechanical properties are shown in Table 2.

[0061] Example 5: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0062] 4.68 g (0.005 mol) of the thiol compound (A3) prepared in Example 4, 2.06 g (0.00375 mol) of the bio-based maleimide (B2) prepared in Example 4, 0.138 g (0.6 mmol) of 1-hydroxycyclohexylphenyl ketone, and 20 g of N,N-dimethylformamide were added to a reaction flask and irradiated with 650 W UV light for 40 minutes to carry out a thiol-olefin click reaction, synthesizing 5.84 g (0.5 mmol) of a bio-based end-thiol hyperbranched polymer. 0.91 g (0.008 mol) of allyl glycidyl ether was added to the mixed solution after the click reaction, and irradiated with 800 W UV light for 60 minutes. The solvent was removed by rotary evaporation to synthesize a bio-based hyperbranched epoxy resin (BMEP-6) containing an imide structure.

[0063] 3.6 g of imide-containing bio-based hyperbranched epoxy resin (BMEP-6), 8.23 ​​g of 4,4'-diaminodiphenylmethane, and 26.4 g of bisphenol A type epoxy resin were blended, cast into specimens, and cured under the following conditions: 60℃ for 2 hours, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin was obtained, and its mechanical properties are shown in Table 2.

[0064] Example 6: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0065] 6 g (0.048 mol) of 2-hydroxymethyl-5-aminopyridine, 6.22 g (0.072 mol) of formaldehyde aqueous solution and 30 g of anhydrous ethanol were added to a reaction flask and stirred at 95 °C for 4 hours to obtain 6.58 g (0.016 mol) of hydroxyl-terminated compound; then 6.41 g (0.06 mol) of MPA, 0.650 g of 4-dimethylaminopyridine catalyst and 32.9 g of acetone were added to the reaction flask and stirred at 25 °C for 10 hours. The solvent was removed by rotary evaporation to obtain the mercapto compound (A3). 4 g (0.023 mol) of N-phenylmaleimide, 6.41 g (0.051 mol) of 2,5-furandimethylamine, 3.04 g (0.023 mol) of heptathiol and 20 g of N,N-dimethylformamide were added to a reaction flask and stirred at 75 °C for 10 hours to obtain a diamino compound. Then, 12.99 g (0.0552 mol) of maleic anhydride was added to the reaction flask and stirred at 135 °C for 10 hours. The solvent was removed by rotary evaporation to obtain bio-based maleimide (B2). 4.68 g (0.007 mol) of thiol compound (A3), 3.08 g (0.00525 mol) of bio-based maleimide (B2), 0.164 g (0.8 mmol) of 1-hydroxycyclohexylphenyl ketone, and 20 g of N,N-dimethylformamide were added to a reaction flask and irradiated with 650 W UV light for 60 minutes to carry out a thiol-olefin click reaction, synthesizing 5.43 g (0.0018 mol) of bio-based end-thiol hyperbranched polymer. 1.37 g (0.012 mol) of allyl glycidyl ether was added to the mixed solution after the click reaction, and irradiated with 400 W UV light for 80 minutes. The solvent was removed by rotary evaporation to synthesize a bio-based hyperbranched epoxy resin (HMEP-6) containing an imide structure.

[0066] 2.4 g of imide-containing bio-based hyperbranched epoxy resin (HMEP-6), 11.58 g of 4,4'-diaminodiphenylmethane, and 37.6 g of bisphenol A type epoxy resin were blended, cast into specimens, and cured under the following conditions: 60℃ for 2 hours, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin was obtained, and its mechanical properties are shown in Table 2.

[0067] Example 7: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0068] 6 g (0.048 mol) of 2-amino-3-hydroxymethylpyridine, 5.22 g (0.058 mol) of paraformaldehyde and 30 g of anhydrous ethanol were added to a reaction flask and stirred at 80 °C for 6 hours to obtain 6.58 g (0.016 mol) of a hydroxyl-terminated compound. Then, 6.16 g (0.0576 mol) of MPA, 0.885 g of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide catalyst and 32.9 g of acetone were added to the reaction flask and stirred at 25 °C for 10 hours. The solvent was removed by rotary evaporation to obtain a mercapto compound (A3). 4 g (0.023 mol) of N-phenylmaleimide, 5.83 g (0.046 mol) of 2,5-furandimethylamine, 2.53 g (0.023 mol) of benzyl thiol and 20 g of N,N-dimethylformamide were added to a reaction flask and stirred at 90 °C for 12 hours to obtain a diamino compound. Then, 10.92 g (0.0506 mol) of maleic anhydride was added to the reaction flask and stirred at 150 °C for 12 hours. The solvent was removed by rotary evaporation to obtain bio-based maleimide (B2). 4.68 g (0.007 mol) of thiol compound (A3), 3.31 g (0.00525 mol) of bio-based maleimide (B2), 1.19 g (0.008 mol) of p-aminophenylacetone, and 20 g of N,N-dimethylformamide were added to a reaction flask and irradiated with 800 W UV light for 30 minutes to carry out a thiol-olefin click reaction, synthesizing 6.50 g (0.0018 mol) of bio-based end-thiol hyperbranched polymer. 1.37 g (0.012 mol) of allyl glycidyl ether was added to the mixed solution after the click reaction, and irradiated with 400 W UV light for 75 minutes. The solvent was removed by rotary evaporation to synthesize a bio-based hyperbranched epoxy resin (BEEP-6) containing an imide structure.

[0069] 2.4 g of imide-containing bio-based hyperbranched epoxy resin (BEEP-6), 11.58 g of 4,4'-diaminodiphenylmethane, and 37.6 g of bisphenol A epoxy resin were blended, cast into specimens, and cured under the following conditions: 60℃ for 2 hours, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A epoxy resin was obtained, and its mechanical properties are shown in Table 2.

[0070] Example 8: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0071] 2.4 g of the imide-containing bio-based hyperbranched epoxy resin (BEEP-6) prepared in Example 7, 11.58 g of 4,4'-diaminodiphenylmethane, and 37.6 g of bisphenol A type epoxy resin were blended, cast into specimens, and cured under the following conditions: 70°C for 2 hours, 100°C for 3 hours, 120°C for 2.5 hours, and 150°C for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin was obtained, and its mechanical properties are shown in Table 3.

[0072] Example 9: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0073] 6 g (0.048 mol) of 2-hydroxymethyl-5-aminopyridine, 5.22 g (0.058 mol) of trioxymethylene and 30 g of anhydrous ethanol were added to a reaction flask and stirred at 85 °C for 6 hours to obtain 6.58 g (0.016 mol) of a hydroxyl-terminated compound. Then, 5.31 g (0.0576 mol) of TGA, 0.982 g of p-toluenesulfonic acid catalyst and 32.9 g of tetrahydrofuran were added to the reaction flask and stirred at 25 °C for 10 hours. The solvent was removed by rotary evaporation to obtain a mercapto compound (A3). 4 g (0.023 mol) of N-phenylmaleimide, 5.83 g (0.046 mol) of 2,5-furandimethylamine, 2.53 g (0.023 mol) of benzyl thiol and 20 g of 1,4-dioxane were added to a reaction flask and stirred at 100 °C for 15 hours to obtain a diamino compound. Then, 10.92 g (0.0506 mol) of maleic anhydride was added to the reaction flask and stirred at 160 °C for 13 hours. The solvent was removed by rotary evaporation to obtain bio-based maleimide (B2). 4.68 g (0.007 mol) of thiol compound (A3), 4.08 g (0.00525 mol) of bio-based maleimide (B2), 0.179 g (0.7 mmol) of 2,2-dimethoxy-2-phenylacetophenone, and 20 g of N,N-dimethylformamide were added to a reaction flask and irradiated with 650 W UV light for 40 minutes to carry out a thiol-olefin click reaction, synthesizing 6.16 g (0.0018 mol) of a bio-based end-thiol hyperbranched polymer. 1.37 g (0.012 mol) of allyl glycidyl ether was added to the mixed solution after the click reaction, and irradiated with 400 W UV light for 80 minutes. The solvent was removed by rotary evaporation to synthesize a bio-based hyperbranched epoxy resin (BEHEP-6) containing an imide structure.

[0074] 2.4 g of imide-containing bio-based hyperbranched epoxy resin (BEHEP-6), 11.57 g of 4,4'-diaminodiphenylmethane, and 37.6 g of bisphenol A type epoxy resin were blended, cast into specimens, and cured under the following conditions: 60℃ for 1 hour, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin was obtained, and its mechanical properties are shown in Table 3.

[0075] Example 10: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0076] 6 g (0.048 mol) of 2-amino-3-hydroxymethylpyridine, 6.22 g (0.072 mol) of formaldehyde aqueous solution and 30 g of anhydrous ethanol were added to a reaction flask and stirred at 95 °C for 4 hours to obtain 6.58 g (0.016 mol) of hydroxyl-terminated compound. Then, 6.41 g (0.06 mol) of MPA, 0.650 g of 4-dimethylaminopyridine catalyst and 32.9 g of acetone were added to the reaction flask and stirred at 25 °C for 10 hours. The solvent was removed by rotary evaporation to obtain the mercapto compound (A3). 4 g (0.023 mol) of N-phenylmaleimide, 6.41 g (0.051 mol) of 2,5-furandimethylamine, 2.56 g (0.023 mol) of 4-pyridinium thiol and 20 g of N,N-dimethylformamide were added to a reaction flask and stirred at 75 °C for 10 hours to obtain a diamino compound. Then, 12.99 g (0.0552 mol) of maleic anhydride was added to the reaction flask and stirred at 135 °C for 10 hours. The solvent was removed by rotary evaporation to obtain bio-based maleimide (B2). 4.68 g (0.007 mol) of thiol compound (A3), 3.52 g (0.006 mol) of bio-based maleimide (B2), 0.164 g (0.8 mmol) of 1-hydroxycyclohexylphenyl ketone, and 20 g of N,N-dimethylformamide were added to a reaction flask and irradiated with 650 W UV light for 40 minutes to carry out a thiol-olefin click reaction, synthesizing 7.33 g (0.7 mmol) of bio-based end-thiol hyperbranched polymer. 1.03 g (0.009 mol) of allyl glycidyl ether was added to the mixed solution after the click reaction, and irradiated with 800 W UV light for 60 minutes. The solvent was removed by rotary evaporation to synthesize a bio-based hyperbranched epoxy resin (MMEP-12) containing an imide structure.

[0077] 3.6 g of imide-containing bio-based hyperbranched epoxy resin (MMEP-12), 8.21 g of 4,4'-diaminodiphenylmethane, and 26.4 g of bisphenol A type epoxy resin were blended, cast into specimens, and cured under the following conditions: 60℃ for 2 hours, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin was obtained, and its mechanical properties are shown in Table 3.

[0078] Example 11: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0079] 6 g (0.048 mol) of 3-amino-4-hydroxymethylpyridine, 4.56 g (0.053 mol) of formaldehyde aqueous solution and 30 g of anhydrous ethanol were added to a reaction flask and stirred at 65 °C for 7 hours to obtain 6.58 g (0.016 mol) of hydroxyl-terminated compound. Then, 4.86 g (0.0528 mol) of TGA, 0.838 g of catalyst 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide and 32.9 g of tetrahydrofuran were added to the reaction flask and stirred at 25 °C for 10 hours. The solvent was removed by rotary evaporation to obtain the mercapto compound (A3). 4 g (0.023 mol) of N-phenylmaleimide, 4.37 g (0.035 mol) of 2,5-furandimethylamine, 2.56 g (0.023 mol) of 4-pyridinethiol and 1,4-dioxane were added to a reaction flask and stirred at 75 °C for 10 hours to obtain a diamino compound. Then, 9.02 g (0.046 mol) of maleic anhydride was added to the reaction flask and stirred at 135 °C for 10 hours. The solvent was removed by rotary evaporation to obtain bio-based maleimide (B2). 4.68 g (0.007 mol) of thiol compound (A3), 4.14 g (0.006 mol) of bio-based maleimide (B2), 0.134 g (0.9 mmol) of p-aminophenylacetone, and 20 g of N,N-dimethylformamide were added to a reaction flask and irradiated with 650 W UV light for 40 minutes to carry out a thiol-olefin click reaction, synthesizing 7.23 g (0.7 mmol) of bio-based end-thiol hyperbranched polymer. 1.03 g (0.009 mol) of allyl glycidyl ether was added to the mixed solution after the click reaction, and irradiated with 800 W UV light for 60 minutes. The solvent was removed by rotary evaporation to synthesize a bio-based hyperbranched epoxy resin (MEMEP-12) containing an imide structure.

[0080] 3.6 g of imide-containing bio-based hyperbranched epoxy resin, 8.22 g of 4,4'-diaminodiphenylmethane, and 26.4 g of bisphenol A type epoxy resin were blended, cast into specimens, and cured under the following conditions: 60℃ for 1 hour, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin was obtained, and its mechanical properties are shown in Table 3.

[0081] Example 12: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0082] 6 g (0.048 mol) of 2-hydroxymethyl-5-aminopyridine, 5.22 g (0.058 mol) of trioxymethylene, and 30 g of anhydrous ethanol were added to a reaction flask and stirred at 85 °C for 6 hours to obtain 6.58 g (0.016 mol) of a hydroxyl-terminated compound. Then, 6.41 g (0.0576 mol) of MPA, 0.650 g of 4-dimethylaminopyridine catalyst, and 32.9 g of acetone were added to the reaction flask and stirred at 25 °C for 10 hours. The solvent was removed by rotary evaporation to obtain a mercapto compound (A3). 4 g (0.023 mol) of N-phenylmaleimide, 6.41 g (0.051 mol) of 2,5-furandimethylamine, 6.59 g (0.023 mol) of octadecyl mercaptan, and 20 g of N,N-dimethylformamide were added to a reaction flask and stirred at 75 °C for 10 hours to obtain a diamino compound. Then, 12.99 g (0.0552 mol) of maleic anhydride was added to the reaction flask and stirred at 135 °C for 10 hours. The solvent was removed by rotary evaporation to obtain bio-based maleimide (B2). 4.68 g (0.007 mol) of thiol compound (A3), 3.52 g (0.006 mol) of bio-based maleimide (B2), 0.164 g (0.8 mmol) of 1-hydroxycyclohexylphenyl ketone, and 20 g of N,N-dimethylformamide were added to a reaction flask and irradiated with 650 W UV light for 40 minutes to carry out a thiol-olefin click reaction, synthesizing 8.45 g (0.7 mmol) of bio-based end-thiol hyperbranched polymer. 1.03 g (0.009 mol) of allyl glycidyl ether was added to the mixed solution after the click reaction, and irradiated with 800 W UV light for 60 minutes. The solvent was removed by rotary evaporation to synthesize a bio-based hyperbranched epoxy resin (OMEP-12) containing an imide structure.

[0083] 3.6 g of imide-containing bio-based hyperbranched epoxy resin, 8.19 g of 4,4'-diaminodiphenylmethane, and 26.4 g of bisphenol A type epoxy resin were blended, cast into specimens, and cured under the following conditions: 60℃ for 1 hour, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin was obtained, and its mechanical properties are shown in Table 3.

[0084] Example 13: A bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing an imide structure and its preparation method, the steps of which are as follows:

[0085] 6 g (0.048 mol) of 2-hydroxymethyl-5-aminopyridine, 5.22 g (0.058 mol) of trioxymethylene and 30 g of anhydrous ethanol were added to a reaction flask and stirred at 85 °C for 6 hours to obtain 6.58 g (0.016 mol) of a hydroxyl-terminated compound. Then, 5.31 g (0.0576 mol) of TGA, 0.982 g of p-toluenesulfonic acid catalyst and 32.9 g of tetrahydrofuran were added to the reaction flask and stirred at 25 °C for 10 hours. The solvent was removed by rotary evaporation to obtain a mercapto compound (A3). 4 g (0.023 mol) of N-phenylmaleimide, 5.83 g (0.046 mol) of 2,5-furandimethylamine, 6.59 g (0.023 mol) of octadecyl mercaptan and 20 g of 1,4-dioxane were added to a reaction flask and stirred at 100 °C for 15 hours to obtain a diamino compound. Then, 10.92 g (0.0506 mol) of maleic anhydride was added to the reaction flask and stirred at 160 °C for 13 hours. The solvent was removed by rotary evaporation to obtain bio-based maleimide (B2). 4.68 g (0.007 mol) of thiol compound (A3), 4.08 g (0.00525 mol) of bio-based maleimide (B2), 0.179 g (0.7 mmol) of 2,2-dimethoxy-2-phenylacetophenone, and 20 g of N,N-dimethylformamide were added to a reaction flask and irradiated with 650 W UV light for 40 minutes to carry out a thiol-olefin click reaction, synthesizing 7.33 g (0.0018 mol) of bio-based end-thiol hyperbranched polymer. 1.37 g (0.012 mol) of allyl glycidyl ether was added to the mixed solution after the click reaction, and irradiated with 400 W UV light for 80 minutes. The solvent was removed by rotary evaporation to synthesize a bio-based hyperbranched epoxy resin (OEMEP-6) containing an imide structure.

[0086] 4.8 g of imide-containing bio-based hyperbranched epoxy resin, 8.60 g of 4,4'-diaminodiphenylmethane, and 27.2 g of bisphenol A type epoxy resin were blended, cast into specimens, and cured under the following conditions: 60℃ for 1 hour, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the composite resin of imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin was obtained, and its mechanical properties are shown in Table 3.

[0087] Comparative Example 1

[0088] 30g of the imide-containing bio-based hyperbranched epoxy resin (TMEP-12) prepared in Example 1 was cured using 1.66g of 4,4'-diaminodiphenylmethane as the curing agent. The curing conditions were: 2 hours at 60°C, 2 hours at 90°C, 3 hours at 130°C, and 2 hours at 160°C. After curing, the resin was removed, and its mechanical properties are shown in Table 2.

[0089] Comparative Example 4

[0090] 30g of the imide-containing bio-based hyperbranched epoxy resin (BMEP-12) prepared in Example 4 was cured using 1.84g of 4,4'-diaminodiphenylmethane as the curing agent. The curing conditions were: 2 hours at 60°C, 2 hours at 90°C, 3 hours at 130°C, and 2 hours at 160°C. After curing, the resin was removed, and its mechanical properties are shown in Table 2.

[0091] Comparative Example 10

[0092] 30g of the imide-containing bio-based hyperbranched epoxy resin (MMEP-12) prepared in Example 10 was cured using 1.80g of 4,4'-diaminodiphenylmethane as the curing agent. The curing conditions were: 2 hours at 60°C, 2 hours at 90°C, 3 hours at 130°C, and 2 hours at 160°C. After curing, the resin was removed, and its mechanical properties are shown in Table 2.

[0093] Comparative Example 12

[0094] 30g of the imide-containing bio-based hyperbranched epoxy resin (OMEP-12) prepared in Example 12 was cured using 1.59g of 4,4'-diaminodiphenylmethane as the curing agent. The curing conditions were: 2 hours at 60°C, 2 hours at 90°C, 3 hours at 130°C, and 2 hours at 160°C. After curing, the resin was removed, and its mechanical properties are shown in Table 2.

[0095] Comparative Example 14

[0096] 30g of bisphenol A epoxy resin was cured using 9.09g of 4,4'-diaminodiphenylmethane as the curing agent. The curing conditions were: 60℃ for 2 hours, 90℃ for 2 hours, 130℃ for 3 hours, and 160℃ for 2 hours. After curing, the resin was removed to obtain pure bisphenol A epoxy resin, and its mechanical properties are shown in Table 2.

[0097] Table 1 Properties of various imide-containing bio-based hyperbranched epoxy resins

[0098]

[0099]

[0100] Table 2 Mechanical properties of various bio-based hyperbranched epoxy resins / bisphenol A type epoxy resin composites containing imide structures

[0101]

[0102] Note: The determination method for "Tensive Strength" in Table 2 is as follows: using a universal testing machine (Instron 5943) and referring to ASTM standard D638-14 "Standard Test Method for Tensile Properties of Polymer-Based Composite Resins"; the determination method for "Flexural Strength" is as follows: using a universal testing machine (Instron 5943) and referring to ASTM standard D790M-92 "Flexural Test Method"; the determination method for "Impact Strength" is as follows: using a CEAST9050 pendulum impact tester and following ASTM standard D256-97, with a test temperature of 25℃.

[0103] 1) The test results in Table 1 show that:

[0104] The number-average molecular weight of the bio-based hyperbranched epoxy resins containing imide structures obtained in Examples 1-13 of this invention gradually increases with the increase of the number of terminal epoxy groups, and reaches the maximum value when the number of terminal groups is 12; the epoxy value gradually decreases with the increase of the number of epoxy groups.

[0105] 2) The test results in Table 2 show that:

[0106] The imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin obtained in this invention has a significant reinforcing and toughening effect on linear epoxy resins such as bisphenol A type epoxy resin. The imide-containing bio-based hyperbranched epoxy resin and bisphenol A type epoxy resin can be blended using 4,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenylmethane, 2,5-furandimethylamine, etc., as curing agents, with 4,4'-diaminodiphenylmethane being the optimal curing agent. (By adjusting the ratio of thiol compounds to bio-based maleimide monomers) Changing the number of terminal epoxy groups in the imide-containing bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin leads to different mechanical properties of the composite resin. When the number of terminal epoxy groups in the bio-based hyperbranched epoxy resin is 12, the composite resin reaches its maximum value in tensile strength, flexural strength, and impact strength. Changing the structure of bio-based maleimide monomers can significantly affect the mechanical properties of bio-based hyperbranched epoxy resin / bisphenol A type epoxy resin composite resin containing imide structure. Specifically, when synthesizing bio-based maleimide monomers, thiols are added to introduce terminal chain groups. Phenyl thiols and pyridine thiols are preferred over aliphatic chain thiols, and among aliphatic chain thiols, short-chain thiols are preferred over long-chain thiols.

Claims

1. A bio-based hyperbranched epoxy resin containing imide structures, characterized in that, The structural formula is as follows general formula (1): General formula (1) Wherein, R structure is pyridine ring, and -CH2O- connected with R is at least one of ortho, meta and para of pyridine; Wherein, R1 is the following structure: n is a natural number of 1 to 5; -CO- in R1is connected with -CH2O-; Wherein, R', R'', R''' are same or different, and respectively represent the structure of general formula (2), general formula (3) or general formula (4): General formula (2) General formula (3) General formula (4); Wherein, X is one or more of the following structures: R2 is the following structure: R3 is the following structure: Wherein, R4 is one or more of the following structures: carbon atom number is 4-18 aliphatic alkyl, aromatic hydrocarbon group-C6H5, aromatic heterocyclic group-C5H4N structure; The number average molecular weight of the bio-based hyperbranched epoxy resin containing imide structure is 4000-14000g / mol, and the epoxy value is 0.08-0.14mol / 100g.

2. The method of producing a bio-based hyperbranched epoxy resin containing imide structure according to claim 1, characterized in that, It comprises the following steps: (1) the hydroxyl amine, aldehyde compound and anhydrous ethanol are added to the reaction bottle, and stirred at 65-95 DEG C for 4-7 hours to obtain a hydroxyl compound, then the mercapto carboxylic acid, catalyst and organic solvent are added to the reaction bottle, and stirred at 20-30 DEG C for 10-15 hours, and the solvent is removed by rotary evaporation to obtain a mercapto compound; (2) N-phenyl maleimide, 2,5-furan dimethylamine, mercaptan and organic solvent are added to the reaction bottle, and stirred at 75-105 DEG C for 10-15 hours to obtain a diamino compound, then maleic anhydride is added to the reaction bottle, and stirred at 60-170 DEG C for 10-14 hours, and the solvent is removed by rotary evaporation to obtain a bio-based maleimide; (3) the mercapto compound obtained in step (1), the bio-based maleimide obtained in step (2), the photo initiator and the organic solvent are added to the reaction bottle, and the thiol-olefin click reaction is carried out by using ultraviolet light with power of 400W-800W for 20-60 minutes to obtain a bio-based mercapto hyperbranched polymer, then the alkenyl epoxy compound is added to the reaction bottle, and the thiol-olefin click reaction is carried out by using ultraviolet light with power of 400W-800W for 60-100 minutes, and the solvent is removed by rotary evaporation to obtain a bio-based hyperbranched epoxy resin containing imide structure, the number average molecular weight is 4000-14000g / mol, and the epoxy value is 0.08-0.14mol / 100g; In the step (1), the molar ratio of hydroxyl amine to aldehyde compound is 1: (1.1-1.5), the mass ratio of hydroxyl amine to anhydrous ethanol is 1:5, the molar ratio of hydroxyl amine to mercapto carboxylic acid is 1: (1.1-1.25), and the mass of catalyst is 10%-20% of the mass of hydroxyl amine; In the step (2), the molar ratio of N-phenyl maleimide, 2,5-furan dimethylamine and mercaptan is 1: (1.5-2.22):1, and the molar ratio of N-phenyl maleimide to maleic anhydride is 1: (2.0-2.4); In the steps (1)-(3), the added mass of organic solvent is 1-10 times of the total mass of monomers in the step; The molar ratio of the thiol compound to the bio-based maleimide in the step (3) is 1:(0.75-0.9), the molar ratio of the thiol compound to the photoinitiator is 1:(0.1-1.14), and the molar ratio of the thiol compound to the alkenyl epoxy compound is 1:(1.28-1.72).

3. The preparation method according to claim 2, characterized in that, The hydroxyl amine is one or more of 3-amino-4-hydroxymethylpyridine, 2-amino-3- hydroxymethylpyridine, and 2-(hydroxymethyl)-5-aminopyridine; the thiol is C4H9-SH ~ C 18 H 37 -SH, phenylthiol, pyridylthiol.

4. The production method according to claim 2, characterized by, The aldehyde compound is one or more of formaldehyde aqueous solution, trioxane, and polyoxymethylene; the mercapto carboxylic acid is n = 1-5; the alkenyl epoxy compound is one or more of allyl glycidyl ether, 2,3-epoxypropyl acrylate, and 1,2-epoxy-5-hexene.

5. The preparation method according to claim 2, characterized in that, The organic solvents in the steps (1)-(3) are the same or different, and each is independently one or more of tetrahydrofuran, 1,4-dioxane, acetone, and N,N-dimethylformamide; the catalyst is one or more of 4-dimethylaminopyridine, p-toluenesulfonic acid, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide, and stannous oxalate; and the photoinitiator is one or more of benzophenone, p-aminopropiophenone, 2,2-dimethoxy-2-phenylacetophenone, and 1-hydroxycyclohexyl phenyl ketone.

6. A bio-based hyperbranched epoxy resin / bisphenol-A epoxy resin composite resin containing imide structure, characterized by, The composite resin comprises the imide-structure-containing bio-based hyperbranched epoxy resin of claim 1 or the imide-structure-containing bio-based hyperbranched epoxy resin prepared by the method of any one of claims 2-5 and a bisphenol A type epoxy resin.

7. The bio-based hyperbranched epoxy resin / bisphenol-A type epoxy resin hybrid resin according to claim 6, characterized in that, The imide-structure-containing bio-based hyperbranched epoxy resin, the bisphenol A type epoxy resin, and a curing agent are uniformly mixed, poured into a mold, and heat-cured to obtain the composite resin; and the curing agent is one or more of 4,4'-diaminodiphenyl sulfone, 2,5-furandimethylamine, and 4,4'-diaminodiphenylmethane.

8. The bio-based hyperbranched epoxy resin / bisphenol-A type epoxy resin hybrid resin according to claim 7, characterized in that, The mass ratio of the imide-structure-containing bio-based hyperbranched epoxy resin, the bisphenol A type epoxy resin, and the curing agent is 1:(5.67-15.67):(1.45-4.83).

9. Use of the imide-structure-containing bio-based hyperbranched epoxy resin of claim 1 or the imide-structure-containing bio-based hyperbranched epoxy resin prepared by the method of any one of claims 2-5 in reinforcing and toughening a linear epoxy resin.

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