A high-performance degradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material and a preparation method thereof

Abstract

This invention relates to the field of biodegradable hyperbranched epoxy resin-carbon fiber composite materials, specifically disclosing a high-performance biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite material and its preparation method. The specific preparation process is as follows: (1) First, an imide-backbone end-thiol hyperbranched polymer and a hyperbranched epoxy resin are synthesized; (2) Carbon fiber cloth is chemically grafted onto the surface of the end-thiol hyperbranched polymer to obtain modified carbon fiber cloth; (3) The modified carbon fiber cloth is fully impregnated with hyperbranched epoxy resin and E51, and then laminated and cured to obtain a high-strength, biodegradable epoxy resin-carbon fiber composite material. The composite material can be completely degraded in an alkaline alcohol solution, realizing the recycling and reuse of carbon fibers. The process of this invention is simple, and the composite material has high performance, high degradation efficiency, and recycling and reuse functions, and is expected to be used in the manufacture of structural components in the fields of wind turbine blades, aerospace, etc.

Description

Technical Field

[0001] This invention relates to the field of biodegradable hyperbranched epoxy resin-carbon fiber composite materials, specifically to a high-performance biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite material and its preparation method. Background Technology

[0002] Carbon fiber / epoxy resin composites possess advantages such as lightweight, high strength, good thermal stability, chemical corrosion resistance, and good dimensional stability, leading to their increasingly widespread application in aerospace, automotive, and wind power generation fields. However, the high cross-linking density of thermosetting epoxy resins makes the composites somewhat brittle, with poor crack propagation resistance and difficulty in degradation, easily causing pollution. Therefore, how to recycle carbon fiber composite waste has attracted increasing attention from researchers. Due to the irreversible cross-linking network, efficient closed-loop recycling of thermosetting resins and carbon fibers without reducing performance remains a significant challenge.

[0003] Traditional mechanical and chemical recycling methods inevitably damage the properties and dimensions of carbon fibers. Dynamic covalent polymers with certain environmental stimuli responsiveness have been proposed as a sustainable alternative to non-recyclable thermosetting materials. Introducing dynamic covalent bonds such as imines, acetals, and esters into the polymer backbone enables the degradation / dissolution or reuse of thermosetting epoxy resin materials. Furthermore, the imide structure not only exhibits good degradability under alkaline conditions but also possesses outstanding thermal stability, corrosion resistance, and high mechanical properties. Therefore, the inventors of this application have introduced imide structures to invent process technologies for biodegradable hyperbranched epoxy resins (Advanced Materials, 2023, 36; Chemical Engineering Journal 2023, 465) and sulfur-containing biodegradable hyperbranched epoxy resins (ZL201810387204.3; Composites Part B, 2020, 192, 108005), achieving the recycling and reuse of epoxy resins.

[0004] The irreversible cross-linked structure of thermosetting epoxy resin-carbon fiber composites is difficult to decompose during the recycling of high-value-added polymers and carbon fibers, and the mechanical strength of the composites still needs to be improved. Developing a simple, biodegradable epoxy resin / carbon fiber composite preparation technology while maintaining the high mechanical strength, high chemical resistance, heat resistance, dimensional stability, and durability of the composites is the 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 high-performance biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite material and its preparation method.

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

[0007] One technical solution: A high-performance biodegradable imide skeleton hyperbranched epoxy resin, the structural formula of which is shown in general formula (1):

[0008]

[0009] 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):

[0010]

[0011] Where X can be one or two of the following structures:

[0012] The structure of R1 is as follows:

[0013]

[0014] R2 is one of the following structures:

[0015]

[0016] R3 can be one or more of the following structures:

[0017]

[0018] Technical Solution Two: A method for preparing a high-performance biodegradable imide-based hyperbranched epoxy resin, comprising the following steps:

[0019] A diamino compound and a triacid anhydride compound are added to a three-necked flask and stirred at 80-130°C for 8-12 hours. Then, tris(2-hydroxyethyl) isocyanurate (THEIC) is added and stirred at 120-180°C for 10-16 hours to obtain a hydroxyl-terminated hyperbranched polymer. Next, mercaptocarboxylic acid and a dehydrating agent are added and stirred at 120-140°C for another 10-16 hours to obtain a mercapto-terminated hyperbranched polymer. Finally, allyl glycidyl ether (AGE), an organic solvent, and a photoinitiator are added to the three-necked flask and irradiated with 400W-800W ultraviolet light for 30-70 minutes to carry out a thiol-olefin click reaction. After removing the organic solvent, a biodegradable imide-skeletal hyperbranched epoxy resin is obtained.

[0020] Furthermore, the diamino compound is one or more of 4,4'-diaminodiphenyl ether (ODA), 3,4'-diaminodiphenyl ether (3,4'-ODA), 3,3'-diaminodiphenyl sulfone (DADPS), 4,4'-diaminodiphenyl sulfone (DDS), 2,2'-diaminodiphenyl sulfone (DOA), and 4,4'-diaminodiphenyl sulfone (BAS); the triacid anhydride compound is trimellitic anhydride (TMA) or 1,2,4-cyclohexanetricarboxylic anhydride (HTMA); and the mercaptocarboxylic acid is one or two of mercaptopropionic acid (MPA) and mercaptoacetic acid (TGA).

[0021] Furthermore, the molar ratio of the diamino compound, trianic anhydride compound, tris(2-hydroxyethyl) isocyanurate, and mercaptocarboxylic acid is 1:2:(0.9-2):(1.5-8.5), and the molar ratio of mercaptocarboxylic acid to allyl glycidyl ether is 1:1.

[0022] Furthermore, the dehydrating agent is one or both of toluene and xylene, and its mass is 0.5 to 5 times that of tris(2-hydroxyethyl) isocyanurate (THEIC); the organic solvent is one or more of tetrahydrofuran, 1,4-dioxane, ethyl acetate, acetone, chloroform, N,N-dimethylformamide, and dichloromethane, and its mass is 10 to 30 times that of tris(2-hydroxyethyl) isocyanurate (THEIC); the photoinitiator is one or more of 4-dimethylaminopyridine, benzophenone, p-aminoacetone, 2,2-dimethoxy-2-phenylacetophenone, and 1-hydroxycyclohexylphenyl ketone, and its mass is 0.4% to 2% that of allyl glycidyl ether (AGE).

[0023] Furthermore, the number-average molecular weight of the terminal thiol hyperbranched polymer is 1300–16000 g / mol.

[0024] Furthermore, the biodegradable imide skeleton hyperbranched epoxy resin has a number-average molecular weight of 1500–19000 g / mol, an epoxy value of 0.10–0.25 mol / 100 g, and a shape factor of 0.97–2.80.

[0025] Technical Solution Three: A high-performance biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composite material, comprising a biodegradable imide-backed hyperbranched epoxy resin or a biodegradable imide-backed hyperbranched epoxy resin prepared by the above method, blended with bisphenol A type epoxy resin and filled into carbon fiber cloth, and then laminated and cured. Before curing, the carbon fiber cloth is modified by the above-mentioned end-thiol hyperbranched polymer through a thiol-olefin click reaction to obtain a surface-functionalized carbon fiber cloth.

[0026] The mass ratio of the carbon fiber cloth, the biodegradable imide skeleton hyperbranched epoxy resin, and the bisphenol A type epoxy resin is 1:(0.1-0.2):(0.2-0.5).

[0027] Technical Solution 4: A method for preparing a high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material, comprising the following steps:

[0028] The carbon fiber cloth is completely immersed in a mixed solution of end-thiol hyperbranched polymer, organic solvent, and photoinitiator, and irradiated with ultraviolet light at a power of 400-800W for 20-60 minutes to carry out a thiol-olefin click reaction. After the reaction is completed, the carbon fiber cloth is removed and dried at 80-100℃ for 5-15 hours to obtain surface-functionalized carbon fiber cloth (TCF). The TCF is placed in a mold, and a mixture of biodegradable imide skeleton hyperbranched epoxy resin, bisphenol A type epoxy resin, and curing agent is uniformly coated on the TCF in the mold. It is then hot-pressed and cured at 2-10MPa and 100-180℃ for 1-3 hours. After hot pressing, heating is stopped, and lamination is performed at 5-15MPa for 10-20 minutes. Then, the temperature is lowered to below 80℃, and the material is removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin / carbon fiber composite material.

[0029] Furthermore, the carbon fiber cloth is one of commercially available T300, T700 and T800; the number average molecular weight of the terminal thiol hyperbranched polymer is 1300 to 16000 g / mol, and its mass is 0.5 to 2.0 times the mass of the carbon fiber cloth.

[0030] Furthermore, the photoinitiator is one or more of 4-dimethylaminopyridine, benzophenone, p-aminoacetone, 2,2-dimethoxy-2-phenylacetophenone, and 1-hydroxycyclohexylphenyl ketone, and its mass is 0.5% to 3% of the carbon fiber cloth; the organic solvent is one or more of tetrahydrofuran, 1,4-dioxane, ethyl acetate, acetone, chloroform, N,N-dimethylformamide, and dichloromethane, and its mass is 0.5 to 30 times the mass of the carbon fiber cloth.

[0031] Furthermore, the biodegradable imide-based hyperbranched epoxy resin has a number-average molecular weight of 1500–19000 g / mol, an epoxy value of 0.10–0.25 mol / 100 g, and a shape factor of 0.97–2.80. The mass ratio of TCF, biodegradable imide-based hyperbranched epoxy resin, bisphenol A epoxy resin, and curing agent is 1:(0.1–0.2):(0.2–0.5):(0.05–0.1).

[0032] Furthermore, the bisphenol A type epoxy resin is designated as E51.

[0033] Furthermore, the curing agent is one or more of 4,4'-diaminodiphenyl ether (ODA), 3,4'-diaminodiphenyl ether (3,4'-ODA), 3,3'-diaminodiphenyl sulfone (DADPS), 4,4'-diaminodiphenyl sulfone (DDS), 2,2'-diaminodiphenyl sulfide (DOA), and 4,4'-diaminodiphenyl sulfide (BAS).

[0034] Technical Solution 5: The degradation and recycling method for the above-mentioned high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material includes the following steps:

[0035] The biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composite material was immersed in an alkaline alcohol solution and degraded at 130-180℃ for 2-12 hours to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 50-70℃ for 10-24 hours to obtain regenerated carbon fiber cloth. The degradation solution was filtered to obtain filter residue, and the filtered residue was purified by column chromatography to obtain recovered diamine monomers.

[0036] The recycled carbon fiber cloth is then completely immersed in a mixed solution of end-thiol hyperbranched polymer, organic solvent, and photoinitiator, and irradiated with 400-800W ultraviolet light for 20-60 minutes to carry out a thiol-olefin click reaction. After the reaction is complete, the carbon fiber cloth is removed and dried at 80-100℃ for 5-15 hours to obtain surface-functionalized recycled carbon fiber cloth. It is then placed in a mold, and a mixture of biodegradable imide-backed hyperbranched epoxy resin, bisphenol A type epoxy resin, and curing agent is uniformly applied to the surface of the recycled carbon fiber cloth in the mold. It is then hot-pressed and cured at 2-10MPa and 100-180℃ for 1-3 hours. After hot pressing, heating is stopped, and lamination is performed at 5-15MPa for 10-20 minutes. Then, the temperature is lowered to 80℃, and the cloth is removed. This process enables the degradation, recycling, and reuse of high-performance biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composite materials.

[0037] Furthermore, the concentration of the alkaline alcohol solution is 0.10-1.50 mol / L, the alkaline alcohol solution is an alcohol solution of potassium hydroxide and / or sodium hydroxide, the alcohol in the alkaline alcohol solution is methanol and / or ethanol, and the mass percentage of alcohol in the alkaline alcohol solution is 90%-100%. The alkaline alcohol solution can be, for example, an aqueous solution of potassium hydroxide in methanol, an aqueous solution of potassium hydroxide in ethanol, an aqueous solution of potassium hydroxide in ethanol, an aqueous solution of potassium hydroxide in ethanol, an aqueous solution of sodium hydroxide in methanol, an aqueous solution of sodium hydroxide in methanol, an aqueous solution of sodium hydroxide in ethanol, or an aqueous solution of sodium hydroxide in ethanol, etc.

[0038] Furthermore, the mass ratio of the biodegradable imide skeleton hyperbranched epoxy resin / carbon fiber composite material to the alkaline alcohol solution is (3-5):(10-20).

[0039] Furthermore, the recycled carbon fiber cloth obtained after degradation of the biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composite material by alkaline alcohol solution has similar surface properties to the original carbon fiber cloth and the tensile properties of the composite material synthesized from it. It can be used as a new carbon fiber cloth to continue synthesizing biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composite materials.

[0040] Compared with the prior art, the technical solution of the present invention has the following advantages and beneficial effects:

[0041] 1. This invention synthesizes hyperbranched epoxy resin containing an imide structure, and tests the shape factor of the hyperbranched epoxy resin using dynamic and static light scattering techniques, thus realizing that the epoxy resin has a spherical hyperbranched topological structure.

[0042] 2. This invention provides a method for producing a hyperbranched polymer click chemical carbon fiber cloth with end-thiol groups. The introduction of the hyperbranched topology can significantly improve the interfacial interaction between carbon fiber and epoxy resin. The deformable hyperbranched topology can effectively disperse and transfer loads, effectively improving the mechanical properties of the composite material and obtaining a high-strength epoxy resin-carbon fiber composite material.

[0043] 3. This invention blends hyperbranched epoxy resin with bisphenol A type epoxy resin with a linear structure, thereby increasing the polarity of the system, improving compatibility, and effectively enhancing the mechanical properties of the composite material.

[0044] 4. This invention utilizes low-end carbon fiber cloth (such as T300) epoxy resin composite material to obtain the tensile strength of high-end carbon fiber cloth (such as T700, T800).

[0045] 5. The hyperbranched epoxy resin-carbon fiber cloth composite material of the present invention has high performance, high degradation efficiency and recycling and reuse functions, and is expected to be used in the manufacture of structural components in the fields of wind turbine blades, aerospace and other fields.

[0046] 6. The preparation process of the biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber cloth composite material of the present invention is simple, the reaction conditions are mild, the reaction time is short, the raw material cost is low, and degradation and recycling can be achieved under alkaline alcohol solution conditions, making it suitable for industrial production. Attached Figure Description

[0047] Figure 1 The images show SEM images of the raw material carbon fiber cloth T800 (a) and the recycled carbon fiber cloth (b) obtained after soaking in an alkaline alcohol solution in Example 6.

[0048] The surface of the recycled carbon fiber is not much different from that of the original carbon fiber, but several black spots with similar defects appear. Its monofilament tensile strength is slightly lower than that before recycling, which may be because the intermediate steps caused more microcracks on the carbon fiber surface. Detailed Implementation

[0049] 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.

[0050] The carbon fiber cloth used in the examples and comparative examples is one of the commercially available T300, T700 and T800. T300 was purchased from Anqing Kawei Technology Co., Ltd. with specification KCF220T, T700 was purchased from Anqing Kawei Technology Co., Ltd. with specification KCF200T, and T800 was purchased from Anqing Kawei Technology Co., Ltd. with specification KCF260T.

[0051] The bisphenol A type epoxy resin used in the examples and comparative examples is the commercially available E51.

[0052] In the examples and comparative examples, the methanol and ethanol used for the degradation of the composite materials had a purity of 99.9%.

[0053] Example 1: A high-performance biodegradable imide-backed hyperbranched epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0054] (1) Synthesis of hyperbranched epoxy resin

[0055] 2.00 g (10 mmol) of ODA and 3.84 g (20 mmol) of TMA were added to a three-necked flask and stirred at 80 °C for 12 h. Then, 5.22 g (20 mmol) of THEIC was added, and the mixture was stirred at 120 °C for 16 h to obtain a hydroxyl-terminated hyperbranched polymer. Next, 1.59 g (15 mmol) of MPA and 2.61 g of toluene were added to the flask, and the mixture was stirred at 120 °C for another 16 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-3, where the number 3 represents the number of thiol groups, determined by NMR spectroscopy; the same applies below). Its number-average molecular weight is shown in Table 1. Finally, 1.71 g (15 mmol) of AGE, 0.03 g of benzophenone, and 52.20 g of [unspecified ingredient] were added to the flask. 1,4-Dioxane was subjected to a thiol-olefin click reaction by irradiation with 400W ultraviolet light for 70 min. After removing the solvent, hyperbranched epoxy resin (HEP-3) was obtained, and its properties are shown in Table 2.

[0056] (2) Preparation of composite materials

[0057] 3.00g of carbon fiber cloth (T300) was completely immersed in a mixed solution of 1.50g SH-HBP-3, 1.50g tetrahydrofuran, and 0.02g benzophenone. The solution was then irradiated with 400W ultraviolet light for 60min to induce a thiol-olefin click reaction, yielding surface-functionalized carbon fiber cloth, 1-TCF. The 1-TCF was then removed and dried at 80℃ for 15h. 3.00g of the dried 1-TCF was placed in a mold, and 0.30g HEP-3, 1.50g bisphenol A epoxy resin, and 0.15g... The ODA mixture was uniformly coated onto 1-TCF in the mold and hot-pressed at 100°C for 3 hours under 2 MPa conditions. After hot pressing, heating was stopped, and lamination was performed at 5 MPa for 20 minutes. When the temperature dropped to 80°C, the product was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material (hereinafter referred to as composite material for simplicity). Its tensile strength is shown in Table 3.

[0058] (3) Degradation and recycling of composite materials

[0059] 5.00 g of the composite material was immersed in a methanol-water solution of 10.00 g of 1.50 mol / L potassium hydroxide (methanol:water = 9:1, m / m) and degraded at 130 °C for 12 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 50 °C for 24 h to obtain recycled carbon fiber cloth. Then, 1.50 g of the recycled carbon fiber cloth was completely immersed in a mixed solution of 0.75 g SH-HBP-3, 0.75 g tetrahydrofuran, and 0.01 g benzophenone and irradiated with 400 W ultraviolet light for 60 min to carry out a thiol-olefin click reaction. The carbon fiber cloth was then removed and dried at 80 °C for 15 h to obtain surface-functionalized recycled carbon fiber cloth. 1.50 g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and 0.15 g HEP-3, 0.75 g bisphenol A epoxy resin, and 0.075 g... The ODA mixture is uniformly coated onto the surface-functionalized recycled carbon fiber cloth in the mold and hot-pressed at 100°C for 3 hours under 2MPa conditions. After hot pressing, heating is stopped, and lamination is performed at 5MPa for 20 minutes. When the temperature reaches 80°C, the material is removed, thus realizing the degradation, recycling, and reuse of high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0060] Example 2: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0061] (1) Synthesis of hyperbranched epoxy resin

[0062] 1.00 g (5 mmol) of 3,4'-ODA, 1.00 g (5 mmol) of ODA, and 3.96 g (20 mmol) of HTMA were added to a three-necked flask and reacted with the mixture at 90 °C for 11 h. Then, 4.70 g (18 mmol) of THEIC was added, and the mixture was reacted with the mixture at 120 °C for 16 h to obtain a hydroxyl-terminated hyperbranched polymer. Next, 1.84 g (20 mmol) of TGA and 4.61 g of dimethyl ether were added to the flask. Toluene was stirred at 130°C for 15 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-6), the number-average molecular weight of which is shown in Table 1. Finally, 2.28 g (20 mmol) AGE, 0.01 g p-aminophenylacetone and 56.20 g ethyl acetate were added to the flask and the mixture was irradiated with 450 W ultraviolet light for 60 min to carry out a thiol-olefin click reaction. The solvent was removed to obtain a hyperbranched epoxy resin (HEP-6), the properties of which are shown in Table 2.

[0063] (2) Preparation of composite materials

[0064] 3.00g of carbon fiber cloth (T300) was completely immersed in a mixed solution of 1.90g SH-HBP-6, 3g chloroform, 2g acetone, 0.02g benzophenone, and 0.01g 4-dimethylaminopyridine. The solution was then irradiated with 450W ultraviolet light for 50min to induce a thiol-olefin click reaction, yielding surface-functionalized carbon fiber cloth, i.e., 2-TCF. The 2-TCF was then removed and dried in a vacuum oven at 85℃ for 14h. 4.00g of the dried 2-TCF was placed in a mold, and 0.49g of… HEP-6, 1.60g of bisphenol A epoxy resin, 0.15g of ODA and 0.10g of 3,4'-ODA mixture were uniformly coated into 2-TCF in a mold and hot-pressed at 110℃ for 3h under 3MPa. After hot pressing, heating was stopped and lamination was performed at 6MPa for 19min. When the temperature reached 80℃, the product was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0065] (3) Degradation and recycling of composite materials

[0066] 4.00 g of the composite material was immersed in a mixed methanol solution of 16.00 g of 0.15 mol / L potassium hydroxide and sodium hydroxide (potassium hydroxide: sodium hydroxide = 1:1, mol / mol), and degraded at 140 °C for 11 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 55 °C for 20 h to obtain recycled carbon fiber cloth. Then, 1.50 g of the recycled carbon fiber cloth was completely immersed in a mixed solution of 0.75 g SH-HBP-6, 0.75 g tetrahydrofuran, and 0.01 g benzophenone, and irradiated with 400 W ultraviolet light for 60 min to carry out a thiol-olefin click reaction. The carbon fiber cloth was then removed and dried at 80 °C for 15 h to obtain surface-functionalized recycled carbon fiber cloth. 2.00 g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and 0.245 g HEP-6, 0.80 g bisphenol A epoxy resin, 0.075 g ODA, and 0.05 g of... The mixture of 3,4'-ODA was uniformly coated onto the surface-functionalized recycled carbon fiber cloth in the mold, and then hot-pressed at 110℃ for 3 hours under 3MPa conditions. After hot pressing, heating was stopped, and the mixture was laminated at 6MPa for 19 minutes. When the temperature reached 80℃, the mixture was removed, thus realizing the degradation, recycling, and reuse of high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0067] Example 3: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0068] (1) Synthesis of hyperbranched epoxy resin

[0069] 2.48 g (10 mmol) of DADPS and 3.96 g (20 mmol) of HTMA were added to a three-necked flask and reacted with stirring at 100 °C for 10 h. Then, 3.92 g (15 mmol) of THEIC was added, and the reaction was carried out at 140 °C for 14 h to obtain a hydroxyl-terminated hyperbranched polymer. Next, 2.97 g (28 mmol) of MPA, 4.61 g of xylene, and 3 g of toluene were added to the flask, and the reaction was continued with stirring at 130 °C for 14 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-8). The number-average molecular weight is shown in Table 1. Finally, 3.20 g (28 mmol) of AGE, 0.01 g of p-aminophenylacetone, 0.02 g of 4-dimethylaminopyridine, and 0.01 g of... were added to the flask. 2,2-Dimethoxy-2-phenylacetophenone, 56.20 g of ethyl acetate, and 10.28 g of acetone were subjected to a thiol-olefin click reaction under 500 W ultraviolet light for 50 min. After removing the solvent, a hyperbranched epoxy resin (HEP-8) was obtained, the properties of which are shown in Table 2.

[0070] (2) Preparation of composite materials

[0071] 3.00g of carbon fiber cloth (T300) was completely immersed in a mixed solution of 3.01g SH-HBP-8, 3g chloroform, 2g acetone, 10g N,N-dimethylformamide, 0.02g benzophenone, 0.01g 4-dimethylaminopyridine, and 0.01g p-aminophenylacetone. The solution was then irradiated with 550W ultraviolet light for 45min to induce a thiol-olefin click reaction, yielding surface-functionalized carbon fiber cloth, i.e., 3-TCF. The 3-TCF was then removed and dried in a vacuum oven at 90℃ for 12h. 4.00g of the dried 3-TCF was placed in a mold, and 0.49g HEP-8, 1.70g bisphenol A epoxy resin, 0.15g ODA, 0.1g DDS, and 0.10g... The mixture of 3,4'-ODA was uniformly coated onto 3-TCF in a mold and hot-pressed at 130°C for 2 hours under 5 MPa conditions. After hot pressing, heating was stopped, and lamination was performed at 7 MPa for 17 minutes. When the temperature reached 80°C, the product was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0072] (3) Degradation and recycling of composite materials

[0073] 4.00 g of the composite material was immersed in a mixed solution of 15.00 g of 0.32 mol / L potassium hydroxide and sodium hydroxide (potassium hydroxide: sodium hydroxide = 1:1, mol / mol) in ethanol and methanol (ethanol: methanol = 1:1, m / m). After degradation at 150 °C for 10 h, carbon fiber cloth and degradation solution were obtained. The carbon fiber cloth was washed with acetone and dried at 60 °C for 18 h to obtain recycled carbon fiber cloth. Then, 1.50 g of the recycled carbon fiber cloth was completely immersed in 1.505 g of SH-HBP-8, 1.50 g of chloroform, 1.00 g of acetone, 5.00 g of N,N-dimethylformamide, 0.01 g of benzophenone, and 0.005 g of... A thiol-olefin click reaction was carried out in a mixed solution of 4-dimethylaminopyridine and 0.005g p-aminophenylacetone under 550W ultraviolet light for 45min. The carbon fiber cloth was then removed and dried at 90℃ for 12h to obtain surface-functionalized recycled carbon fiber cloth. 2.00g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and a mixture of 0.245g HEP-8, 0.85g bisphenol A epoxy resin, 0.075g ODA, 0.05g DDS, and 0.05g 3,4'-ODA was uniformly coated onto the surface-functionalized recycled carbon fiber cloth in the mold. The mixture was then hot-pressed and cured at 130℃ for 2h at 5MPa. After hot pressing, heating was stopped, and the mixture was laminated at 7MPa for 17min. When the temperature reached 80℃, the cloth was removed, thus realizing the degradation, recycling, and reuse of high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0074] Example 4: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0075] (1) Synthesis of hyperbranched epoxy resin

[0076] 1.24 g (5 mmol) DADPS, 1.00 g (5 mmol) ODA, and 3.96 g (20 mmol) HTMA were added to a three-necked flask and stirred at 110 °C for 9 h. Then, 3.13 g (12 mmol) THEIC was added, and the mixture was stirred at 150 °C for 13 h to obtain a hydroxyl-terminated hyperbranched polymer. Next, 1.01 g (11 mmol) TGA, 2.65 g (25 mmol) MPA, 5.01 g xylene, and 2 g toluene were added to the flask, and the mixture was stirred at 130 °C for 14 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-12-I). The number-average molecular weight is shown in Table 1. Finally, 4.11 g (36 mmol) AGE, 0.02 g 4-dimethylaminopyridine, and 0.02 g... 2,2-Dimethoxy-2-phenylacetophenone, 50.20 g of dichloromethane, and 10.98 g of acetone were subjected to a thiol-olefin click reaction under 550 W ultraviolet light for 40 min. After removing the solvent, a hyperbranched epoxy resin (HEP-12-I) was obtained, the properties of which are shown in Table 2.

[0077] (2) Preparation of composite materials

[0078] 4.00g of carbon fiber cloth (T700) was completely immersed in a mixed solution of 3.33g SH-HBP-12-I, 3.14g tetrahydrofuran, 2.58g acetone, 10.13g N,N-dimethylformamide, 0.02g 1-hydroxycyclohexylphenyl ketone, 0.02g 4-dimethylaminopyridine, and 0.01g p-aminophenylacetone. The solution was irradiated with 650W ultraviolet light for 40min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth, i.e., 4-TCF. The 4-TCF was then removed and dried at 95℃ for 10h. 4.00g of the dried 4-TCF was placed in a mold, and 0.50g HEP-12-I, 1.50g bisphenol A epoxy resin, 0.15g DOA, and 0.1g... The mixture of DDS and 0.08g of 3,4'-ODA was uniformly coated onto 4-TCF in the mold and hot-pressed at 150℃ for 2 hours at 8MPa. After hot pressing, heating was stopped, and lamination was performed at 9MPa for 15 minutes. When the temperature reached 80℃, the product was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0079] (3) Degradation and recycling of composite materials

[0080] 5.00 g of the composite material was immersed in a mixed methanol-water solution of 12.00 g of 0.42 mol / L potassium hydroxide and sodium hydroxide (potassium hydroxide:sodium hydroxide = 1:1, mol / mol) (methanol:water = 9:1, m / m), and degraded at 155 °C for 9 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 65 °C for 15 h to obtain recycled carbon fiber cloth. Then, 2.00 g of the recycled carbon fiber cloth was completely immersed in 1.665 g of SH-HBP-12-Ⅰ, 1.57 g of tetrahydrofuran, 1.29 g of acetone, 5.065 g of N,N-dimethylformamide, 0.01 g of 1-hydroxycyclohexylphenyl ketone, and 0.01 g of [unclear - possibly a specific compound or solution]. A thiol-olefin click reaction was carried out in a mixed solution of 4-dimethylaminopyridine and 0.005g p-aminophenylacetone under 650W ultraviolet light for 40min. The carbon fiber cloth was then removed and dried at 95℃ for 10h to obtain surface-functionalized recycled carbon fiber cloth. 2.00g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and a mixture of 0.25g HEP-12-Ⅰ, 0.75g bisphenol A epoxy resin, 0.075g DOA, 0.05g DDS, and 0.04g 3,4'-ODA was uniformly coated onto the surface-functionalized recycled carbon fiber cloth in the mold. The mixture was then hot-pressed and cured at 150℃ for 2h at 8MPa. After hot pressing, heating was stopped, and the mixture was laminated at 9MPa for 15min. When the temperature reached 80℃, the mixture was removed, thus realizing the degradation, recycling, and reuse of high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0081] Example 5: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0082] (1) Synthesis of hyperbranched epoxy resin

[0083] 1.08 g (5 mmol) DOA, 1.08 g (5 mmol) BAS, and 3.84 g (20 mmol) TMA were added to a three-necked flask and stirred at 90 °C for 11 h. Then, 4.70 g (18 mmol) THEIC was added, and the mixture was stirred at 140 °C for 13 h to obtain a hydroxyl-terminated hyperbranched polymer. 3.68 g (40 mmol) TGA and 11.61 g xylene were added to the flask, and the mixture was stirred at 130 °C for 14 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-15). The number-average molecular weight is shown in Table 1. Finally, 4.57 g (40 mmol) AGE, 0.02 g p-aminophenylacetone, and 66.20 g ethyl acetate were added to the flask, and the mixture was irradiated with 450 W UV light for 60 min to carry out a thiol-olefin click reaction. After removing the solvent, a hyperbranched epoxy resin (HEP-15) was obtained, the properties of which are shown in Table 2.

[0084] (2) Preparation of composite materials

[0085] 3.00g of carbon fiber cloth (T700) was completely immersed in a mixed solution of 1.50g SH-HBP-15, 3.00g dichloromethane, 10g acetone, 0.02g benzophenone, and 0.01g 4-dimethylaminopyridine. The solution was then irradiated with 450W ultraviolet light for 50min to induce a thiol-olefin click reaction, yielding surface-functionalized carbon fiber cloth, i.e., 5-TCF. The 5-TCF was then removed and dried at 85℃ for 14h. 4.00g of the dried 5-TCF was placed in a mold, and 0.48g HEP-15, 1.10g bisphenol A epoxy resin, 0.10g ODA, and 0.10g... The mixture of 3,4'-ODA was uniformly coated onto 5-TCF in the mold and hot-pressed at 160℃ for 2 hours under 6MPa. After hot pressing, heating was stopped, and lamination was performed at 10MPa for 15 minutes. When the temperature reached 80℃, the product was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin / carbon fiber composite material. Its tensile strength is shown in Table 3.

[0086] (3) Degradation and recycling of composite materials

[0087] 4.00 g of the composite material was immersed in a mixed methanol-water solution of 17.00 g of 0.35 mol / L potassium hydroxide and sodium hydroxide (potassium hydroxide: sodium hydroxide = 1:1, mol / mol) (methanol:water = 9:1, m / m), and degraded at 160 °C for 6 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 55 °C for 20 h to obtain recycled carbon fiber cloth. Then, 1.50 g of the recycled carbon fiber cloth was completely immersed in a mixed solution of 0.75 g SH-HBP-15, 1.50 g dichloromethane, 5 g acetone, 0.01 g benzophenone, and 0.005 g 4-dimethylaminopyridine, and irradiated with 450 W ultraviolet light for 50 min to carry out a thiol-olefin click reaction. The carbon fiber cloth was then removed and dried at 85 °C for 14 h to obtain surface-functionalized recycled carbon fiber cloth. 2.00 g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and 0.24 g of... A mixture of HEP-15, 0.55g of bisphenol A epoxy resin, 0.05g of ODA, and 0.05g of 3,4'-ODA was uniformly applied to a surface-functionalized recycled carbon fiber cloth in a mold. The mixture was then hot-pressed and cured at 160℃ for 2 hours under 6MPa. After hot pressing, heating was stopped, and the mixture was laminated at 10MPa for 15 minutes. Once the temperature reached 80℃, the mixture was removed. This process enables the degradation, recycling, and reuse of high-performance biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite materials. The tensile strength of the composite is shown in Table 3.

[0088] Example 6: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0089] (1) Synthesis of hyperbranched epoxy resin

[0090] 1.24 g (5 mmol) DADPS, 0.65 g (3 mmol) BAS, 0.43 g (2 mmol) DOA, and 3.84 g (20 mmol) TMA were added to a three-necked flask and reacted with stirring at 115 °C for 10 h. Then, 3.13 g (12 mmol) THEIC was added, and the reaction was carried out at 150 °C for 13 h to obtain a hydroxyl-terminated hyperbranched polymer. Next, 2.76 g (30 mmol) TGA, 3.18 g (30 mmol) MPA, 4.10 g xylene, and 5.00 g toluene were added to the flask, and the reaction was continued with stirring at 135 °C for 11 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-18), the number-average molecular weight of which is shown in Table 1. Finally, 6.85 g (60 mmol) AGE, 0.05 g 1-hydroxycyclohexylphenyl ketone, 0.04 g p-aminoacetone, and 0.02 g [other components] were added to the flask. 2,2-Dimethoxy-2-phenylacetophenone, 12.32 g acetone, 5.12 g tetrahydrofuran and 18.15 g dichloromethane were subjected to a thiol-olefin click reaction under ultraviolet light with a power of 550 W for 65 min. After removing the solvent, hyperbranched epoxy resin (HEP-18) was obtained, and its properties are shown in Table 2.

[0091] (2) Preparation of composite materials

[0092] 5.00g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 3.90g SH-HBP-18, 10g acetone, 20g tetrahydrofuran, 80g ethyl acetate, 0.03g benzophenone, 0.03g 4-dimethylaminopyridine, and 0.03g p-aminophenylacetone. The solution was irradiated with 750W ultraviolet light for 30min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth, i.e., 6-TCF. The 6-TCF was then removed and dried at 85℃ for 7h. 4.00g of the dried 6-TCF was placed in a mold, and 0.45g HEP-18, 0.85g bisphenol A epoxy resin, 0.06g DADPS, 0.02g DDS, 0.10g ODA, and 0.10g... The BAS mixture was uniformly coated onto 6-TCF in the mold and hot-pressed at 180°C for 1 hour at 9 MPa. After hot pressing, heating was stopped, and lamination was performed at 13 MPa for 12 minutes. When the temperature reached 80°C, the product was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0093] (3) Degradation and recycling of composite materials

[0094] 5.00 g of the composite material was immersed in a methanol-water solution of 15.00 g of 0.11 mol / L potassium hydroxide (methanol:water = 9:1, m / m) and degraded at 160 °C for 6 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 55 °C for 19 h to obtain recycled carbon fiber cloth. Then, 2.50 g of the recycled carbon fiber cloth was completely immersed in a mixed solution of 1.95 g SH-HBP-18, 5 g acetone, 10 g tetrahydrofuran, 40 g ethyl acetate, 0.015 g benzophenone, 0.015 g 4-dimethylaminopyridine, and 0.03 g p-aminophenylacetone. The solution was irradiated with 750 W ultraviolet light for 30 min to carry out a thiol-olefin click reaction. The carbon fiber cloth was then removed and dried at 85 °C for 7 h to obtain surface-functionalized recycled carbon fiber cloth. 2.00 g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and 0.225 g of... A mixture of HEP-18, 0.425g bisphenol A epoxy resin, 0.03g DADPS, 0.01g DDS, 0.05g ODA, and 0.05g BAS was uniformly applied to a mold with surface-functionalized recycled carbon fiber cloth. The mixture was then hot-pressed at 180℃ for 1 hour at 9MPa. After hot pressing, heating was stopped, and the mixture was laminated at 13MPa for 12 minutes. Once the temperature reached 80℃, the mixture was removed. This process enables the degradation, recycling, and reuse of high-performance biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite materials. The tensile strength of the composite is shown in Table 3.

[0095] Example 7: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0096] (1) Synthesis of hyperbranched epoxy resin

[0097] 1.24 g (5 mmol) DDS, 0.65 g (3 mmol) DOA, 0.43 g (2 mmol) BAS, and 3.84 g (20 mmol) TMA were added to a three-necked flask and stirred at 120 °C for 9 h. Then, 2.61 g (10 mmol) THEIC was added, and the mixture was stirred at 160 °C for 12 h to obtain a hydroxyl-terminated hyperbranched polymer. Next, 6.45 g (70 mmol) TGA, 4.10 g xylene, and 2.00 g toluene were added to the flask, and the mixture was stirred at 140 °C for 10 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-20), the number-average molecular weight of which is shown in Table 1. Finally, 7.99 g (70 mmol) AGE, 0.06 g 1-hydroxycyclohexylphenyl ketone, 0.05 g p-aminoacetone, and 0.02 g [other components] were added to the flask. 2,2-Dimethoxy-2-phenylacetophenone, 12.32 g acetone and 18.15 g dichloromethane were subjected to a thiol-olefin click reaction under 600 W ultraviolet light for 60 min. After removing the solvent, a hyperbranched epoxy resin (HEP-20) was obtained, the properties of which are shown in Table 2.

[0098] (2) Preparation of composite materials

[0099] 5.00g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 5.00g SH-HBP-20, 40g chloroform, 20g tetrahydrofuran, 80g ethyl acetate, 0.04g benzophenone, 0.03g 4-dimethylaminopyridine, and 0.05g p-aminophenylacetone. The solution was irradiated with 800W ultraviolet light for 20min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth, i.e., 7-TCF. The 7-TCF was then removed and dried at 90℃ for 6h. 4.00g of the dried 7-TCF was placed in a mold, and 0.50g HEP-20, 0.80g bisphenol A epoxy resin, 0.05g DADPS, 0.05g DDS, 0.10g ODA, and 0.10g... The BAS mixture was uniformly coated onto 7-TCF in the mold and hot-pressed at 180°C for 1 hour under 10 MPa. After hot pressing, heating was stopped, and lamination was performed at 15 MPa for 10 minutes. When the temperature dropped to 80°C, the product was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0100] (3) Degradation and recycling of composite materials

[0101] 5.00 g of the composite material was immersed in an ethanol solution of 16.00 g of 0.80 mol / L potassium hydroxide and degraded at 170 °C for 4 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was rinsed with acetone and dried at 60 °C for 18 h to obtain recycled carbon fiber cloth. Then, 2.50 g of the recycled carbon fiber cloth was completely immersed in a mixed solution of 2.50 g SH-HBP-20, 20 g chloroform, 10 g tetrahydrofuran, 40 g ethyl acetate, 0.02 g benzophenone, 0.015 g 4-dimethylaminopyridine, and 0.025 g p-aminophenylacetone. The solution was irradiated with 800 W ultraviolet light for 20 min to carry out a thiol-olefin click reaction. The carbon fiber cloth was then removed and dried at 90 °C for 6 h to obtain surface-functionalized recycled carbon fiber cloth. 2.00 g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and 0.25 g of... A mixture of HEP-20, 0.40g bisphenol A epoxy resin, 0.025g DADPS, 0.025g DDS, 0.05g ODA, and 0.05g BAS is uniformly applied to a mold with surface-functionalized recycled carbon fiber cloth. The mixture is then hot-pressed at 180℃ for 1 hour at 10MPa. After hot pressing, heating is stopped, and the mixture is laminated at 15MPa for 10 minutes. Once the temperature reaches 80℃, the mixture is removed. This process enables the degradation, recycling, and reuse of high-performance biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite materials. The tensile strength is shown in Table 3.

[0102] Example 8: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0103] (1) Synthesis of hyperbranched epoxy resin

[0104] 1.24 g (5 mmol) DADPS, 0.65 g (3 mmol) DOA, 0.43 g (2 mmol) BAS, and 3.96 g (20 mmol) HTMA were added to a three-necked flask and stirred at 130 °C for 8 h. Then, 2.35 g (9 mmol) THEIC was added, and the mixture was stirred at 180 °C for 10 h to obtain a hydroxyl-terminated hyperbranched polymer. Next, 7.83 g (85 mmol) TGA, 4.80 g xylene, and 7.00 g toluene were added to the flask, and the mixture was stirred at 140 °C for another 10 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-24). The number-average molecular weight is shown in Table 1. Finally, 9.70 g (85 mmol) AGE, 0.09 g 1-hydroxycyclohexylphenyl ketone, 0.05 g 4-dimethylaminopyridine, and 0.05 g hydroxyl-terminated methyl methacrylate (HTMA) were added to the flask. 2,2-Dimethoxy-2-phenylacetophenone, 57.60 g of dichloromethane, and 12.90 g of tetrahydrofuran were subjected to a thiol-olefin click reaction under ultraviolet light with a power of 800 W for 30 min. After removing the solvent, a hyperbranched epoxy resin (HEP-24) was obtained, the properties of which are shown in Table 2.

[0105] (2) Preparation of composite materials

[0106] 5.00g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 10.00g SH-HBP-24, 50g chloroform, 20g acetone, 80g ethyl acetate, 0.05g benzophenone, 0.04g 4-dimethylaminopyridine, and 0.06g p-aminophenylacetone. The solution was then irradiated with 800W ultraviolet light for 20min to carry out a thiol-olefin click reaction, yielding surface-functionalized carbon fiber cloth, i.e., 8-TCF. The 8-TCF was removed and dried at 100℃ for 5h. 4.00g of the dried 8-TCF was placed in a mold, and 0.80g HEP-24, 0.80g bisphenol A epoxy resin, 0.05g ODA, 0.10g DDS, 0.10g 3,4'-ODA, and 0.10g... The BAS mixture was uniformly coated onto 8-TCF in the mold and hot-pressed at 180°C for 1 hour under 10 MPa. After hot pressing, heating was stopped, and the mixture was laminated at 15 MPa for 10 minutes. When the temperature reached 80°C, it was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0107] (3) Degradation and recycling of composite materials

[0108] 5.00 g of the composite material was immersed in a mixed ethanol solution of 20.00 g of 0.10 mol / L potassium hydroxide and sodium hydroxide (potassium hydroxide: sodium hydroxide = 1:1, mol / mol), and degraded at 180 °C for 2 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was rinsed with acetone and dried at 70 °C for 10 h to obtain recycled carbon fiber cloth. Then, 2.50 g of the recycled carbon fiber cloth was completely immersed in a mixed solution of 5.00 g SH-HBP-24, 25 g chloroform, 10 g acetone, 40 g ethyl acetate, 0.025 g benzophenone, 0.02 g 4-dimethylaminopyridine, and 0.03 g p-aminophenylacetone, and irradiated with 800 W ultraviolet light for 20 min to carry out a thiol-olefin click reaction. The carbon fiber cloth was then removed and dried at 100 °C for 5 h to obtain surface-functionalized recycled carbon fiber cloth. 2.00 g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and 0.40 g of... A mixture of HEP-24, 0.40g bisphenol A epoxy resin, 0.025g ODA, 0.05g DDS, 0.05g 3,4'-ODA, and 0.05g BAS was uniformly applied to a mold with surface-functionalized recycled carbon fiber cloth. The mixture was then hot-pressed at 180℃ for 1 hour at 10MPa. After hot pressing, heating was stopped, and the mixture was laminated at 15MPa for 10 minutes. Once the temperature reached 80℃, the mixture was removed. This process enables the degradation, recycling, and reuse of high-performance biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite materials. The tensile strength is shown in Table 3.

[0109] Example 9: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0110] (1) Preparation of composite materials

[0111] 4.00g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 3.33g SH-HBP-12-Ⅰ (prepared in Example 4), 3.14g tetrahydrofuran, 2.58g acetone, 10.13g N,N-dimethylformamide, 0.02g 1-hydroxycyclohexylphenyl ketone, 0.02g 4-dimethylaminopyridine, and 0.01g p-aminophenylacetone. The solution was irradiated with 650W ultraviolet light for 40min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth, i.e., 9-TCF. The 9-TCF was then removed and dried at 95℃ for 10h. 4.00g of the dried 9-TCF was placed in a mold, and 0.50g HEP-12-Ⅰ (prepared in Example 4), 1.50g bisphenol A epoxy resin, 0.15g DOA, and 0.1g... The mixture of DDS and 0.08g of 3,4'-ODA was uniformly coated onto 9-TCF in the mold and hot-pressed at 150℃ for 2 hours under 8MPa. After hot pressing, heating was stopped, and lamination was performed at 9MPa for 15 minutes. When the temperature reached 80℃, the product was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0112] (2) Degradation and recycling of composite materials

[0113] 5.00 g of the composite material was immersed in a mixed methanol-water solution (methanol:water = 9:1, m / m) of 12.00 g of 0.42 mol / L potassium hydroxide and sodium hydroxide (potassium hydroxide:sodium hydroxide = 1:1, mol / mol) at 155 °C for 9 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was then washed with acetone and dried at 65 °C for 15 h to obtain recycled carbon fiber cloth. Then, 2.00 g of the recycled carbon fiber cloth was completely immersed in 1.665 g of SH-HBP-12-Ⅰ (prepared in Example 4), 1.57 g of tetrahydrofuran, 1.29 g of acetone, 5.065 g of N,N-dimethylformamide, 0.01 g of 1-hydroxycyclohexylphenyl ketone, and 0.01 g of... A thiol-olefin click reaction was carried out in a mixed solution of 4-dimethylaminopyridine and 0.005g p-aminophenylacetone under 650W ultraviolet light for 40min. The carbon fiber cloth was then removed and dried at 95℃ for 10h to obtain surface-functionalized recycled carbon fiber cloth. 2.00g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and a mixture of 0.25g HEP-12-Ⅰ (prepared in Example 4), 0.75g bisphenol A epoxy resin, 0.075g DOA, 0.05g DDS, and 0.04g 3,4'-ODA was uniformly coated onto the surface-functionalized recycled carbon fiber cloth in the mold. The mixture was then hot-pressed and cured at 150℃ for 2h at 8MPa. After hot pressing, heating was stopped, and the mixture was laminated at 9MPa for 15min. When the temperature reached 80℃, the cloth was removed, thus realizing the degradation, recycling, and reuse of high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0114] Example 10: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0115] (1) Preparation of composite materials

[0116] 5.00 g of carbon fiber cloth (T300) was completely immersed in a mixed solution of 0.90 g SH-HBP-8 (prepared in Example 3), 1.20 g SH-HBP-6 (prepared in Example 2), 2.90 g SH-HBP-20 (prepared in Example 7), 40 g chloroform, 20 g tetrahydrofuran, 80 g ethyl acetate, 0.04 g benzophenone, 0.03 g 4-dimethylaminopyridine, and 0.05 g p-aminophenylacetone. The solution was irradiated with 800 W ultraviolet light for 20 min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth, i.e., 10-TCF. The 10-TCF was removed and dried at 90 °C for 6 h. 4.00 g of the dried 10-TCF was placed in a mold, and 0.30 g HEP-6 (prepared in Example 2), 0.20 g... A mixture of HEP-20 (prepared in Example 7), 0.80 g of bisphenol A epoxy resin, 0.05 g of DADPS, 0.05 g of DDS, 0.10 g of ODA, and 0.10 g of BAS was uniformly coated onto 10-TCF in a mold and hot-pressed at 180°C for 1 h at 10 MPa. After hot pressing, heating was stopped, and lamination was performed at 15 MPa for 10 min. When the temperature dropped to 80°C, the product was removed, yielding a high-performance biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0117] (2) Degradation and recycling of composite materials

[0118] 5.00 g of the composite material was immersed in an ethanol solution of 16.00 g of 0.80 mol / L potassium hydroxide and degraded at 170 °C for 4 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 60 °C for 18 h to obtain recycled carbon fiber cloth. Then, 2.50 g of the recycled carbon fiber cloth was completely immersed in 0.45 g of SH-HBP-8 (prepared in Example 3), 0.60 g of SH-HBP-6 (prepared in Example 2), 1.45 g of SH-HBP-20 (prepared in Example 7), 20 g of chloroform, 10 g of tetrahydrofuran, 40 g of ethyl acetate, 0.02 g of benzophenone, and 0.015 g of... A thiol-olefin click reaction was carried out in a mixed solution of 4-dimethylaminopyridine and 0.025g p-aminophenylacetone under 800W ultraviolet light for 20 min. The carbon fiber cloth was then removed and dried at 90℃ for 6 h to obtain surface-functionalized regenerated carbon fiber cloth. 2.00g of the dried surface-functionalized regenerated carbon fiber cloth was placed in a mold, and 0.15g HEP-6 (prepared in Example 2), 0.10g HEP-20 (prepared in Example 7), 0.40g bisphenol A epoxy resin, 0.025g DADPS, 0.025g DDS, 0.05g ODA, and 0.05g... The BAS mixture is uniformly coated onto the functionalized recycled carbon fiber cloth on the mold surface and hot-pressed at 180°C for 1 hour under 10 MPa. After hot pressing, heating is stopped, and lamination is performed at 15 MPa for 10 minutes. When the temperature reaches 80°C, the material is removed, thus realizing the degradation, recycling, and reuse of high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. The tensile strength is shown in Table 3.

[0119] Example 11: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0120] (1) Preparation of composite materials

[0121] 5.00g of carbon fiber cloth (T700) was completely immersed in a mixed solution of 1.90g SH-HBP-6 (prepared in Example 2), 4.20g SH-HBP-8 (prepared in Example 3), 3.90g SH-HBP-24 (prepared in Example 8), 50g chloroform, 20g acetone, 80g ethyl acetate, 0.05g benzophenone, 0.04g 4-dimethylaminopyridine, and 0.06g p-aminophenylacetone. The solution was irradiated with 800W ultraviolet light for 20min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth, i.e., 11-TCF. The 11-TCF was removed and dried at 100℃ for 5h. 4.00g of the dried 11-TCF was placed in a mold, and 0.20g HEP-12-I (prepared in Example 4), 0.20g HEP-15 (prepared in Example 5), and 0.40g... A mixture of HEP-20 (prepared in Example 7), 0.80 g of bisphenol A epoxy resin, 0.05 g of ODA, 0.1 g of DDS, 0.10 g of 3,4'-ODA, and 0.10 g of BAS was uniformly coated onto 11-TCF in a mold and hot-pressed at 180°C for 1 h at 10 MPa. After hot pressing, heating was stopped, and lamination was performed at 15 MPa for 10 min. When the temperature reached 80°C, the product was removed to obtain a high-performance biodegradable imide-backed hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0122] (2) Degradation and recycling of composite materials

[0123] 5.00 g of the composite material was immersed in a mixed ethanol solution of 20.00 g of 0.10 mol / L potassium hydroxide and sodium hydroxide (potassium hydroxide: sodium hydroxide = 1:1, mol / mol), and degraded at 180 °C for 2 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 70 °C for 10 h to obtain regenerated carbon fiber cloth. Then, 2.50 g of the regenerated carbon fiber cloth was completely immersed in 0.95 g of SH-HBP-6 (prepared in Example 2), 2.10 g of SH-HBP-8 (prepared in Example 3), 0.95 g of SH-HBP-24 (prepared in Example 8), 25 g of chloroform, 10 g of acetone, 40 g of ethyl acetate, 0.025 g of benzophenone, and 0.02 g of... In a mixed solution of 4-dimethylaminopyridine and 0.03g p-aminophenylacetone, a thiol-olefin click reaction was carried out by irradiation with 800W ultraviolet light for 20 min. The carbon fiber cloth was then removed and dried at 100℃ for 5 h to obtain surface-functionalized regenerated carbon fiber cloth. 2.00g of the dried surface-functionalized regenerated carbon fiber cloth was placed in a mold, and 0.10g HEP-12-I (prepared in Example 4), 0.10g HEP-15 (prepared in Example 5), 0.20g HEP-20 (prepared in Example 7), 0.40g bisphenol A type epoxy resin, 0.025g ODA, 0.025g DDS, and 0.025g 3,4'-ODA were added. The BAS mixture is uniformly coated onto the surface-functionalized recycled carbon fiber cloth in the mold and hot-pressed at 180°C for 1 hour under 10 MPa. After hot pressing, heating is stopped, and lamination is performed at 15 MPa for 10 minutes. When the temperature reaches 80°C, the material is removed, thus realizing the degradation, recycling, and reuse of high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0124] Example 12: A high-performance biodegradable epoxy resin-carbon fiber composite material and its preparation method, the steps of which are as follows:

[0125] (1) Preparation of composite materials

[0126] 4.00 g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 1.50 g SH-HBP-3 (prepared in Example 1), 1.51 g SH-HBP-12-I (prepared in Example 4), 3.14 g tetrahydrofuran, 2.58 g acetone, 10.13 g N,N-dimethylformamide, 0.02 g 1-hydroxycyclohexylphenyl ketone, 0.02 g 4-dimethylaminopyridine, and 0.01 g p-aminophenylacetone. The solution was irradiated with 650 W UV light for 40 min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth, i.e., 12-TCF. The 12-TCF was then removed and dried at 95 °C for 10 h. 4.00 g of the dried 12-TCF was placed in a mold, and 0.31 g HEP-6 (prepared in Example 2) and 0.19 g... HEP-8 (prepared in Example 3), 1.50 g of bisphenol A epoxy resin, 0.15 g of DOA, 0.1 g of DDS, and 0.08 g of 3,4'-ODA mixture were uniformly coated onto 11-TCF in a mold and hot-pressed at 150°C for 2 h at 8 MPa. After hot pressing, heating was stopped, and lamination was performed at 9 MPa for 15 min. When the temperature reached 80°C, the product was removed to obtain a high-performance biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composite material. Its tensile strength is shown in Table 3.

[0127] (2) Degradation and recycling of composite materials

[0128] 5.00 g of the composite material was immersed in a mixed methanol-water solution of 12.00 g of 0.42 mol / L potassium hydroxide and sodium hydroxide (potassium hydroxide: sodium hydroxide = 1:1, mol / mol) (methanol:water = 9:1, m / m), and degraded at 155 °C for 9 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 65 °C for 15 h to obtain recycled carbon fiber cloth. Then, 2.00 g of the recycled carbon fiber cloth was completely immersed in 0.75 g of SH-HBP-3 (prepared in Example 1), 0.755 g of SH-HBP-12-I (prepared in Example 4), 1.57 g of tetrahydrofuran, 1.29 g of acetone, 5.065 g of N,N-dimethylformamide, 0.01 g of 1-hydroxycyclohexylphenyl ketone, and 0.01 g of... A thiol-olefin click reaction was carried out in a mixed solution of 4-dimethylaminopyridine and 0.005g p-aminophenylacetone under UV light at 650W for 40min. The carbon fiber cloth was then removed and dried at 95℃ for 10h to obtain surface-functionalized recycled carbon fiber cloth. 2.00g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and a mixture of 0.155g HEP-6 (prepared in Example 2), 0.095g HEP-8 (prepared in Example 3), 0.75g bisphenol A epoxy resin, 0.075g DOA, 0.05g DDS, and 0.04g 3,4'-ODA was uniformly coated onto the surface-functionalized recycled carbon fiber cloth in the mold. The mixture was then hot-pressed and cured at 150℃ for 2h at 8MPa. After hot pressing, heating was stopped, and the mixture was laminated at 9MPa for 15min. When the temperature reached 80℃, the cloth was removed, thus realizing the degradation, recycling, and reuse of high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material. Its tensile strength is shown in Table 3.

[0129] Comparative Example 1:

[0130] 4.00g of carbon fiber cloth (T300) was placed in a mold. A mixture of 2.09g of bisphenol A epoxy resin, 0.15g of ODA and 0.10g of 3,4'-ODA was evenly coated onto the carbon fiber cloth in the mold. The mixture was then hot-pressed and cured at 110℃ for 3h under 3MPa. After hot pressing, heating was stopped, and the mixture was laminated at 6MPa for 19min. When the temperature reached 80℃, the mixture was removed to obtain the epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0131] Comparative Example 2:

[0132] 4.00g of carbon fiber cloth (T700) was placed in a mold. A mixture of 2.00g of bisphenol A epoxy resin, 0.15g of DOA, 0.1g of DDS and 0.08g of 3,4'-ODA was evenly coated onto the carbon fiber cloth in the mold. The mixture was then hot-pressed and cured at 150℃ for 2 hours at 8MPa. After hot pressing, heating was stopped, and the mixture was laminated at 9MPa for 15 minutes. When the temperature reached 80℃, the mixture was removed to obtain the epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0133] Comparative Example 3:

[0134] 4.00g of carbon fiber cloth (T800) was placed in a mold. A mixture of 1.30g of bisphenol A epoxy resin, 0.06g of DADPS, 0.02g of DDS, 0.10g of ODA, and 0.10g of BAS was evenly coated onto the carbon fiber cloth in the mold. The mixture was then hot-pressed and cured at 180℃ for 1 hour at 9MPa. After hot pressing, heating was stopped, and the mixture was laminated at 13MPa for 12 minutes. When the temperature reached 80℃, the mixture was removed to obtain the epoxy resin-carbon fiber composite material. The tensile strength of the composite material is shown in Table 3.

[0135] Comparative Example 4:

[0136] (1) Synthesis of hyperbranched epoxy resin

[0137] The preparation principle and process of the synthesized end-thiol hyperbranched polymer DSPI-12 and hyperbranched epoxy resin DIHE-12 were referred to in Xu Haifeng's master's thesis "Preparation and Performance Study of Imidia-Skeleton Hyperbranched Epoxy Resin / Carbon Fiber Composites" (pp. 18-19).

[0138] (2) Preparation of composite materials

[0139] 5.00g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 3.90g DSPI-12, 10g acetone, 20g tetrahydrofuran, 80g ethyl acetate, 0.03g benzophenone, 0.03g 4-dimethylaminopyridine, and 0.03g p-aminophenylacetone. The solution was irradiated with 750W ultraviolet light for 30min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth. The surface-functionalized carbon fiber cloth was removed and dried at 85℃ for 7h. 4.00g of the dried surface-functionalized carbon fiber cloth was placed in a mold, and 1.30g DIHE-12, 0.06g DADPS, 0.02g DDS, 0.10g ODA, and 0.10g... The BAS mixture was uniformly coated onto the surface-functionalized carbon fiber cloth in the mold and hot-pressed at 180°C for 1 hour under 9 MPa conditions. After hot pressing, heating was stopped, and lamination was performed at 13 MPa for 12 minutes. When the temperature reached 80°C, the material was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0140] (3) Degradation and recycling of composite materials

[0141] 5.00 g of the composite material was immersed in a methanol-water solution of 15.00 g of 0.11 mol / L potassium hydroxide (methanol:water = 9:1, m / m) and degraded at 160 °C for 6 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 55 °C for 19 h to obtain recycled carbon fiber cloth. Then, 2.50 g of the recycled carbon fiber cloth was completely immersed in a mixed solution of 1.95 g DSPI-12, 5 g acetone, 10 g tetrahydrofuran, 40 g ethyl acetate, 0.015 g benzophenone, 0.015 g 4-dimethylaminopyridine, and 0.015 g p-aminophenylacetone, and irradiated with 750 W ultraviolet light for 30 min to carry out a thiol-olefin click reaction. The carbon fiber cloth was then removed and dried at 85 °C for 7 h to obtain surface-functionalized recycled carbon fiber cloth. 2.00 g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and 0.225 g of... A mixture of DIHE-12, 0.425g bisphenol A epoxy resin, 0.03g DADPS, 0.01g DDS, 0.05g ODA, and 0.05g BAS was uniformly coated onto the functionalized recycled carbon fiber cloth on the mold surface. It was then hot-pressed and cured at 180℃ for 1 hour under 9MPa. After hot pressing, heating was stopped, and the mixture was laminated at 13MPa for 12 minutes. When the temperature reached 80℃, the mixture was removed. This process enables the degradation, recycling, and reuse of high-performance biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite materials. The tensile strength is shown in Table 3.

[0142] Comparative Example 5:

[0143] (1) Synthesis of hyperbranched epoxy resin

[0144] The preparation principle and process of the synthesized end-thiol hyperbranched polymer DSPI-12 and hyperbranched epoxy resin DIHE-12 were referred to in Xu Haifeng's master's thesis "Preparation and Performance Study of Imidia-Skeleton Hyperbranched Epoxy Resin / Carbon Fiber Composites" (pp. 18-19).

[0145] (2) Preparation of composite materials

[0146] 5.00g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 3.90g DSPI-12, 10g acetone, 20g tetrahydrofuran, 80g ethyl acetate, 0.03g benzophenone, 0.03g 4-dimethylaminopyridine, and 0.03g p-aminophenylacetone. The solution was irradiated with 750W ultraviolet light for 30min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth. The surface-functionalized carbon fiber cloth was removed and dried at 85℃ for 7h. 4.00g of the dried surface-functionalized carbon fiber cloth was placed in a mold, and 0.45g DIHE-12, 0.85g bisphenol A epoxy resin, 0.06g DADPS, 0.02g DDS, 0.10g ODA, and 0.10g... The BAS mixture was uniformly coated onto the surface-functionalized carbon fiber cloth in the mold and hot-pressed at 180°C for 1 hour under 9 MPa conditions. After hot pressing, heating was stopped, and lamination was performed at 13 MPa for 12 minutes. When the temperature reached 80°C, the material was removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0147] (3) Degradation and recycling of composite materials

[0148] 5.00 g of the composite material was immersed in a methanol-water solution of 15.00 g of 0.11 mol / L potassium hydroxide (methanol:water = 9:1, m / m) and degraded at 160 °C for 6 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 55 °C for 19 h to obtain recycled carbon fiber cloth. Then, 2.50 g of the recycled carbon fiber cloth was completely immersed in a mixed solution of 1.95 g DSPI-12, 5 g acetone, 10 g tetrahydrofuran, 40 g ethyl acetate, 0.015 g benzophenone, 0.015 g 4-dimethylaminopyridine, and 0.015 g p-aminophenylacetone, and irradiated with 750 W ultraviolet light for 30 min to carry out a thiol-olefin click reaction. The carbon fiber cloth was then removed and dried at 85 °C for 7 h to obtain surface-functionalized recycled carbon fiber cloth. 2.00 g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and 0.225 g of... A mixture of DIHE-12, 0.425g bisphenol A epoxy resin, 0.03g DADPS, 0.01g DDS, 0.05g ODA, and 0.05g BAS was uniformly coated onto the functionalized recycled carbon fiber cloth on the mold surface. It was then hot-pressed and cured at 180℃ for 1 hour under 9MPa. After hot pressing, heating was stopped, and the mixture was laminated at 13MPa for 12 minutes. When the temperature reached 80℃, the mixture was removed. This process enables the degradation, recycling, and reuse of high-performance biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite materials. The tensile strength is shown in Table 3.

[0149] Comparative Example 6:

[0150] (1) Preparation of composite materials

[0151] 5.00 g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 3.90 g SH-HBP-18 (prepared in Example 6), 10 g acetone, 20 g tetrahydrofuran, 80 g ethyl acetate, 0.03 g benzophenone, 0.03 g 4-dimethylaminopyridine, and 0.03 g p-aminophenylacetone. The solution was irradiated with 750 W UV light for 30 min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth, i.e., 6-TCF. The 6-TCF was then removed and dried at 85 °C for 7 h. 4.00 g of the dried 6-TCF was placed in a mold, and 1.30 g HEP-18 (prepared in Example 6), 0.06 g DADPS, 0.02 g DDS, 0.10 g ODA, and 0.10 g... The BAS mixture was uniformly coated onto 6-TCF in the mold and hot-pressed at 180°C for 1 hour at 9 MPa. After hot pressing, heating was stopped, and lamination was performed at 13 MPa for 12 minutes. When the temperature reached 80°C, the mixture was removed to obtain the imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0152] (2) Degradation and recycling of composite materials

[0153] 5.00 g of the composite material was immersed in a methanol aqueous solution of 15.00 g of 0.11 mol / L potassium hydroxide (methanol:water = 9:1, m / m), and degraded at 160 °C for 6 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 55 °C for 19 h to obtain recycled carbon fiber cloth. Then, 2.50 g of the recycled carbon fiber cloth was completely immersed in 1.95 g of SH-HBP-18 (prepared in Example 6), 5 g of acetone, 10 g of tetrahydrofuran, 40 g of ethyl acetate, 0.015 g of benzophenone and 0.015 g of... A thiol-olefin click reaction was carried out in a mixed solution of 4-dimethylaminopyridine and 0.015g p-aminophenylacetone under 750W ultraviolet light for 30min. The carbon fiber cloth was then removed and dried at 85℃ for 7h to obtain surface-functionalized recycled carbon fiber cloth. 2.00g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and a mixture of 0.65g HEP-18 (prepared in Example 6), 0.03g DADPS, 0.01g DDS, 0.05g ODA, and 0.05g BAS was uniformly coated onto the surface-functionalized recycled carbon fiber cloth in the mold. The mixture was then hot-pressed and cured at 180℃ for 1h under 9MPa. After hot pressing, heating was stopped, and the mixture was laminated at 13MPa for 12min. When the temperature reached 80℃, the cloth was removed, thus realizing the degradation, recycling, and reuse of the biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0154] Comparative Example 7:

[0155] (1) Synthesis of hyperbranched epoxy resin

[0156] 2.00 g (10 mmol) of 3,4'-ODA and 3.84 g (20 mmol) of TMA were added to a three-necked flask and reacted with stirring at 115 °C for 10 h. Then, 3.13 g (12 mmol) of THEIC was added, and the reaction was carried out at 150 °C for 13 h to obtain a hydroxyl-terminated hyperbranched polymer. Next, 1.01 g (11 mmol) of TGA, 2.65 g (25 mmol) of MPA, 5.01 g of xylene, and 2 g of toluene were added to the flask, and the reaction was continued with stirring at 130 °C for 14 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-12-II). The number-average molecular weight is shown in Table 1. Finally, 4.11 g (36 mmol) of AGE and 0.02 g of TMA were added to the flask. 4-Dimethylaminopyridine, 0.02 g of 2,2-dimethoxy-2-phenylacetophenone, 50.20 g of dichloromethane, and 10.98 g of acetone were subjected to a thiol-olefin click reaction under 550 W ultraviolet light for 40 min. After removing the solvent, a hyperbranched epoxy resin (HEP-12-II) was obtained, the properties of which are shown in Table 2.

[0157] (2) Preparation of composite materials

[0158] 5.00 g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 3.90 g SH-HBP-12-II (prepared in Comparative Example 7), 10 g acetone, 20 g tetrahydrofuran, 80 g ethyl acetate, 0.03 g benzophenone, 0.03 g 4-dimethylaminopyridine, and 0.03 g p-aminophenylacetone. The solution was irradiated with 750 W UV light for 30 min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth. The surface-functionalized carbon fiber cloth was removed and dried at 85 °C for 7 h. 4.00 g of the dried surface-functionalized carbon fiber cloth was placed in a mold, and 1.30 g HEP-12-II (prepared in Comparative Example 7), 0.06 g DADPS, 0.02 g DDS, 0.10 g ODA, and 0.10 g... The BAS mixture was uniformly coated onto the surface-functionalized carbon fiber cloth in the mold and hot-pressed at 180°C for 1 hour at 9 MPa. After hot pressing, heating was stopped, and the mixture was laminated at 13 MPa for 12 minutes. When the temperature reached 80°C, the mixture was removed to obtain the imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0159] (3) Degradation and recycling of composite materials

[0160] 5.00 g of the composite material was immersed in a methanol aqueous solution of 15.00 g of 0.11 mol / L potassium hydroxide (methanol:water = 9:1, m / m), and degraded at 160 °C for 6 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 55 °C for 19 h to obtain recycled carbon fiber cloth. Then, 2.50 g of the recycled carbon fiber cloth was completely immersed in 1.95 g of SH-HBP-12-II (prepared in Comparative Example 7), 5 g of acetone, 10 g of tetrahydrofuran, 40 g of ethyl acetate, 0.015 g of benzophenone, and 0.015 g of... A thiol-olefin click reaction was carried out in a mixed solution of 4-dimethylaminopyridine and 0.015g p-aminophenylacetone under 750W ultraviolet light for 30min. The carbon fiber cloth was then removed and dried at 85℃ for 7h to obtain surface-functionalized recycled carbon fiber cloth. 2.00g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and a mixture of 0.65g HEP-12-II (prepared in Comparative Example 7), 0.03g DADPS, 0.01g DDS, 0.05g ODA, and 0.05g BAS was uniformly coated onto the surface-functionalized recycled carbon fiber cloth in the mold. The mixture was then hot-pressed at 180℃ for 1h at 9MPa. After hot pressing, heating was stopped, and the mixture was laminated at 13MPa for 12min. When the temperature reached 80℃, the cloth was removed, thus realizing the degradation, recycling, and reuse of the biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0161] Comparative Example 8:

[0162] (1) Synthesis of hyperbranched epoxy resin

[0163] 2.16 g (10 mmol) of BAS and 3.84 g (20 mmol) of TMA were added to a three-necked flask and reacted with stirring at 115 °C for 10 h. Then, 3.13 g (12 mmol) of THEIC was added, and the reaction was carried out at 150 °C for 13 h to obtain a hydroxyl-terminated hyperbranched polymer. Next, 1.01 g (11 mmol) of TGA, 2.65 g (25 mmol) of MPA, 5.01 g of xylene, and 2 g of toluene were added to the flask, and the reaction was continued with stirring at 130 °C for 14 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-12-III). The number-average molecular weight is shown in Table 1. Finally, 4.11 g (36 mmol) of AGE and 0.02 g of... 4-Dimethylaminopyridine, 0.02 g of 2,2-dimethoxy-2-phenylacetophenone, 50.20 g of dichloromethane, and 10.98 g of acetone were subjected to a thiol-olefin click reaction under ultraviolet light with a power of 550 W for 40 min. After removing the solvent, a hyperbranched epoxy resin (HEP-12-III) was obtained, the properties of which are shown in Table 2.

[0164] (2) Preparation of composite materials

[0165] 5.00 g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 3.90 g SH-HBP-12-III (prepared in Comparative Example 8), 10 g acetone, 20 g tetrahydrofuran, 80 g ethyl acetate, 0.03 g benzophenone, 0.03 g 4-dimethylaminopyridine, and 0.03 g p-aminophenylacetone. The solution was irradiated with 750 W UV light for 30 min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth. The surface-functionalized carbon fiber cloth was removed and dried at 85 °C for 7 h. 4.00 g of the dried surface-functionalized carbon fiber cloth was placed in a mold, and 1.30 g HEP-12-III (prepared in Comparative Example 8), 0.06 g DADPS, 0.02 g DDS, 0.10 g ODA, and 0.10 g... The BAS mixture was uniformly coated onto the surface-functionalized carbon fiber cloth in the mold and hot-pressed at 180°C for 1 hour at 9 MPa. After hot pressing, heating was stopped, and the mixture was laminated at 13 MPa for 12 minutes. When the temperature reached 80°C, the mixture was removed to obtain the imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0166] (3) Degradation and recycling of composite materials

[0167] 5.00 g of the composite material was immersed in a methanol aqueous solution of 15.00 g of 0.11 mol / L potassium hydroxide (methanol:water = 9:1, m / m), and degraded at 160 °C for 6 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 55 °C for 19 h to obtain regenerated carbon fiber cloth. Then, 2.50 g of the regenerated carbon fiber cloth was completely immersed in a mixed solution of 1.95 g SH-HBP-12-III (prepared in Comparative Example 8), 5 g acetone, 10 g tetrahydrofuran, 40 g ethyl acetate, 0.015 g benzophenone, 0.015 g 4-dimethylaminopyridine, and 0.015 g p-aminophenylacetone. The solution was irradiated with 750 W ultraviolet light for 30 min to carry out a thiol-olefin click reaction. The carbon fiber cloth was then removed and dried at 85 °C for 7 h to obtain surface-functionalized regenerated carbon fiber cloth. 2.00 g of the dried surface-functionalized regenerated carbon fiber cloth was placed in a mold, and 0.65 g of... A mixture of HEP-12-III (prepared in Comparative Example 8), 0.03 g DADPS, 0.01 g DDS, 0.05 g ODA, and 0.05 g BAS was uniformly applied to the surface-functionalized recycled carbon fiber cloth in a mold and hot-pressed at 180°C for 1 hour at 9 MPa. After hot pressing, heating was stopped, and lamination was performed at 13 MPa for 12 minutes. When the temperature reached 80°C, the material was removed, thus realizing the degradation, recycling, and reuse of the biodegradable imide-backbone hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0168] Comparative Example 9:

[0169] (1) Synthesis of hyperbranched epoxy resin

[0170] 2.48 g (10 mmol) of DDS and 3.84 g (20 mmol) of TMA were added to a three-necked flask and reacted with stirring at 115 °C for 10 h. Then, 3.13 g (12 mmol) of THEIC was added, and the reaction was carried out at 150 °C for 13 h to obtain a hydroxyl-terminated hyperbranched polymer. Next, 1.01 g (11 mmol) of TGA, 2.65 g (25 mmol) of MPA, 5.01 g of xylene, and 2 g of toluene were added to the flask, and the reaction was continued with stirring at 130 °C for 14 h to obtain a thiol-terminated hyperbranched polymer (SH-HBP-12-IV). The number-average molecular weight is shown in Table 1. Finally, 4.11 g (36 mmol) of AGE and 0.02 g of... 4-Dimethylaminopyridine, 0.02 g of 2,2-dimethoxy-2-phenylacetophenone, 50.20 g of dichloromethane, and 10.98 g of acetone were subjected to a thiol-olefin click reaction under 550 W ultraviolet light for 40 min. After removing the solvent, a hyperbranched epoxy resin (HEP-12-IV) was obtained, the properties of which are shown in Table 2.

[0171] (2) Preparation of composite materials

[0172] 5.00 g of carbon fiber cloth (T800) was completely immersed in a mixed solution of 3.90 g SH-HBP-12-IV (prepared in Comparative Example 9), 10 g acetone, 20 g tetrahydrofuran, 80 g ethyl acetate, 0.03 g benzophenone, 0.03 g 4-dimethylaminopyridine, and 0.03 g p-aminophenylacetone. The solution was irradiated with 750 W UV light for 30 min to carry out a thiol-olefin click reaction, obtaining surface-functionalized carbon fiber cloth. The surface-functionalized carbon fiber cloth was removed and dried at 85 °C for 7 h. 4.00 g of the dried surface-functionalized carbon fiber cloth was placed in a mold, and 1.30 g HEP-12-IV (prepared in Comparative Example 9), 0.06 g DADPS, 0.02 g DDS, 0.10 g ODA, and 0.10 g... The BAS mixture was uniformly coated onto the surface-functionalized carbon fiber cloth in the mold and hot-pressed at 180°C for 1 hour at 9 MPa. After hot pressing, heating was stopped, and the mixture was laminated at 13 MPa for 12 minutes. When the temperature reached 80°C, the mixture was removed to obtain the imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0173] (3) Degradation and recycling of composite materials

[0174] 5.00 g of the composite material was immersed in a methanol aqueous solution of 15.00 g of 0.11 mol / L potassium hydroxide (methanol:water = 9:1, m / m), and degraded at 160 °C for 6 h to obtain carbon fiber cloth and degradation solution. The carbon fiber cloth was washed with acetone and dried at 55 °C for 19 h to obtain recycled carbon fiber cloth. Then, 2.50 g of the recycled carbon fiber cloth was completely immersed in 1.95 g of SH-HBP-12-IV (prepared in Comparative Example 9), 5 g of acetone, 10 g of tetrahydrofuran, 40 g of ethyl acetate, 0.015 g of benzophenone, and 0.015 g of... A thiol-olefin click reaction was carried out in a mixed solution of 4-dimethylaminopyridine and 0.015g p-aminophenylacetone under 750W ultraviolet light for 30min. The carbon fiber cloth was then removed and dried at 85℃ for 7h to obtain surface-functionalized recycled carbon fiber cloth. 2.00g of the dried surface-functionalized recycled carbon fiber cloth was placed in a mold, and a mixture of 0.65g HEP-12-IV (prepared in Comparative Example 9), 0.03g DADPS, 0.01g DDS, 0.05g ODA, and 0.05g BAS was uniformly coated onto the surface-functionalized recycled carbon fiber cloth in the mold. The mixture was then hot-pressed at 180℃ for 1h at 9MPa. After hot pressing, heating was stopped, and the mixture was laminated at 13MPa for 12min. When the temperature reached 80℃, the cloth was removed, thus realizing the degradation, recycling, and reuse of the biodegradable imide skeleton hyperbranched epoxy resin-carbon fiber composite material. Its tensile strength is shown in Table 3.

[0175] Table 1. Number average molecular weight of terminal thiol hyperbranched polymers

[0176] Product Name Number-average molecular weight (g / mol) SH-HBP-3 1300 SH-HBP-6 3100 SH-HBP-8 4200 SH-HBP-12-I 5900 SH-HBP-12-II 5700 SH-HBP-12-III 5600 SH-HBP-12-IV 5900 SH-HBP-15 6100 SH-HBP-18 8200 SH-HBP-20 10000 SH-HBP-24 16000

[0177] Table 2 Properties of biodegradable imide-skeletal hyperbranched epoxy resins

[0178]

[0179]

[0180] Table 3 Tensile strength of hyperbranched epoxy resin / carbon fiber composites

[0181]

[0182] The number-average molecular weight of the terminal thiol hyperbranched polymers obtained in Examples 1-12 was 1300–16000 g / mol, the number-average molecular weight of the biodegradable imide skeleton hyperbranched epoxy resins obtained was 1500–19000 g / mol, the epoxy value was 0.10–0.25 mol / 100 g, and the shape factor was 0.97–2.80.

[0183] The number-average molecular weight was obtained by gel permeation chromatography (GPC), based on the permeation behavior of hyperbranched polymers in gels, by measuring the ratio of permeation time to standard samples; the epoxy value was obtained by the hydrochloric acid-acetone method, using hydrochloric acid to destroy epoxy groups, then titrating to determine the amount of remaining hydrochloric acid, thus determining the amount of hydrochloric acid that reacted with the epoxy groups, and calculating the amount of epoxy groups to obtain the epoxy value; the shape factor was obtained by dynamic and static light scattering techniques, using static light scattering to obtain the mean square radius of gyration (R0). g Dynamic light scattering technology is used to obtain the hydrodynamic radius (R). h The ratio of the two (R) g / R h This is the shape factor.

[0184] Furthermore, the test results in Table 1 show that the number-average molecular weight of the terminal thiol hyperbranched polymers obtained in Examples 1-8 of the present invention gradually increases with the increase of the number of terminal thiol groups. When the number of terminal thiol groups is 24, the number-average molecular weight reaches its maximum value of 16000 g / mol.

[0185] As can be seen from the test results in Table 2, the number-average molecular weight of the epoxy resins obtained in Examples 1-8 of this invention gradually increases with the increase of the number of terminal epoxy groups, while the epoxy value gradually decreases. The shape factor shows a trend of first decreasing and then increasing. Specifically, when the number of terminal epoxy groups is 24, the number-average molecular weight reaches its maximum of 19000 g / mol, and the epoxy value reaches its minimum of 0.10 mol / 100g. When the number of terminal epoxy groups is 12, the shape factor is the minimum of 0.97. The shape factor data of the hyperbranched epoxy resins indicate that the structures of the hyperbranched epoxy resins in the examples are all elliptical. Among them, HEP-12 has a shape factor value closest to 1, and its structure is the most regular, more closely resembling a sphere.

[0186] The test results in Table 3 show that:

[0187] The tensile strength of the composite materials obtained in Examples 1-12 is much higher than that of the carbon fiber cloth in Comparative Examples 1-3, especially as follows: Example 2 is significantly better than Comparative Example 1, Example 4 is significantly better than Comparative Example 2, and Example 6 is significantly better than Comparative Example 3. In these three groups, the comparative examples only modified the carbon fiber cloth with E51 resin, while the examples used specially made hyperbranched epoxy resin HEP ​​and E51 to modify the carbon fiber cloth, and the other steps and parameters were the same. In Comparative Example 6, specially made hyperbranched epoxy resin HEP-18 was used to modify the carbon fiber cloth T800, and its tensile strength was higher than that of carbon fiber cloth T800 modified with E51 resin (Comparative Example 3). However, the tensile strength of the composite material obtained in Example 6 is significantly better than that of Comparative Examples 3 and 6, proving that the blend system of hyperbranched epoxy resin and linear epoxy resin (epoxy resin E51) has a significant advantage in improving the tensile strength of the composite material, which is far superior to the tensile strength of the carbon fiber cloth composite material cured by a single resin.

[0188] The composite material obtained in Example 9 exhibited the highest tensile strength, demonstrating that HEP-12 showed the best modification effect. This aligns with the trend in Table 2 where the shape factor value of HEP-12 was closest to 1, conforming to the theory that the closer the shape factor is to 1, the more regular the hyperbranched epoxy resin structure and the better its performance. Comparative Examples 6 and 7, 8, and 9 also show that the modification effect of HEP-12 is superior to that of HEP-18. This is mainly due to the difference in the hyperbranched resin structure, and the fundamental reason for this difference is the different diammonium monomers used in the synthesis of the resin. HEP-12 has a stronger interfacial interaction with carbon fibers, resulting in better load transfer capacity and thus higher mechanical properties.

[0189] The tensile strength of the composite material obtained in Example 6 is significantly higher than that of the composite material obtained in Comparative Example 4, demonstrating that the tensile strength of the system of the present invention is improved compared to the systems of the prior art. Although the composite material obtained in Comparative Example 5 shows a significant improvement over Comparative Example 4, it is still lower than the tensile strength of the composite material obtained in Example 6.

[0190] The alkaline alcohol solution degradation system provided by this invention enables the degradation, recycling, and reuse of high-performance biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composites. A comparison of the tensile strength of the composite material prepared from the recycled carbon fiber fabric with the tensile strength of the original composite material shows that the tensile strength of the recycled carbon fiber fabric does not decrease significantly, exhibiting a high retention rate.

[0191] Furthermore, a comparison of the data from Comparative Example 3 and Example 1 shows that with the addition of hyperbranched structural modification, the tensile strength of carbon fiber cloth T300 can reach or even exceed that of T800 before modification.

[0192] In summary, the biodegradable imide-backed hyperbranched epoxy resin of the present invention can significantly improve the tensile strength of composite materials, achieving the goal of using low-grade carbon fiber to achieve the strength of high-grade carbon fiber, while realizing the recycling of carbon fiber, and the tensile strength of the recycled carbon fiber fabric composite material does not decrease significantly.

[0193] Monomer separation and recovery:

[0194] The degradation solution of the composite material in Example 3 was filtered using a Buchner funnel. The filter residue obtained after filtration was a crude product of 3,3'-diaminodiphenyl sulfone. The filter residue was then purified by column chromatography to obtain the recovered 3,3'-diaminodiphenyl sulfone, which was named RDADPS, with a recovery rate of approximately 52%. A novel hyperbranched epoxy resin (RHER-8) was synthesized using RDADPS via the synthesis method in Example 3, and a hyperbranched epoxy resin / carbon fiber composite material was prepared according to the preparation method in Example 3. The tensile strength of this material was 721 ± 12, with a tensile strength retention rate of 96%.

[0195] The method for determining the "tensile strength" in Table 3 is as follows: the test is conducted using a universal testing machine (Instron 5943) in accordance with ASTM standard D3039 / D3039M-00 "Standard Test Method for Tensile Properties of Polymer-Based Composite Materials", and the test temperature is 25℃.

Claims

1. A high-performance biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composite material, characterized in that, The carbon fiber cloth is prepared by blending high-performance biodegradable imide-backbated hyperbranched epoxy resin and bisphenol A type epoxy resin into carbon fiber cloth and then laminating and curing it. Before curing, the carbon fiber cloth is modified by thiol-olefin click reaction with end-thiol hyperbranched polymer to obtain surface-functionalized carbon fiber cloth. The preparation method of the terminal thiol hyperbranched polymer includes: adding a diamino compound and a triacid anhydride compound to a three-necked flask, stirring and reacting at 80-130℃ for 8-12 h, then adding tris(2-hydroxyethyl) isocyanurate, stirring and reacting at 120-180℃ for 10-16 h to obtain the terminal hydroxyl hyperbranched polymer; adding thiol carboxylic acid and a dehydrating agent, and continuing to stir and react at 120-140℃ for 10-16 h to obtain the terminal thiol hyperbranched polymer; The high-performance biodegradable imide skeleton hyperbranched epoxy resin has the following general formula (1): 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): Where X can be one or two of the following structures: The structure of R1 is as follows: R2 is one of the following structures: R3 can be one or more of the following structures: The biodegradable imide-backed hyperbranched epoxy resin has a number-average molecular weight of 1500–19000 g / mol, an epoxy value of 0.10–0.25 mol / 100 g, and a shape factor of 0.97–2.

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2. The high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material according to claim 1, characterized in that, The high-performance biodegradable imide-skeletal hyperbranched epoxy resin is prepared by the following steps: A diamino compound and a triacid anhydride compound were added to a three-necked flask and reacted with stirring at 80-130°C for 8-12 hours. Then, tris(2-hydroxyethyl) isocyanurate was added, and the reaction was carried out with stirring at 120-180°C for 10-16 hours to obtain a hydroxyl-terminated hyperbranched polymer. A mercaptocarboxylic acid and a dehydrating agent were added, and the reaction was continued with stirring at 120-140°C for 10-16 hours to obtain a mercapto-terminated hyperbranched polymer with a number average molecular weight of 1300-1600. 0 g / mol; finally, add allyl glycidyl ether, organic solvent and photoinitiator to the three-necked flask, irradiate with ultraviolet light with a power of 400W-800W for 30-70 min to carry out thiol-olefin click reaction, and then remove the organic solvent to obtain a biodegradable imide skeleton hyperbranched epoxy resin with a number average molecular weight of 1500-19000 g / mol, an epoxy value of 0.10-0.25 mol / 100g and a shape factor of 0.97-2.

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3. The high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material according to claim 2, characterized in that, The molar ratio of the diamino compound, trianic anhydride compound, tris(2-hydroxyethyl) isocyanurate, and mercaptocarboxylic acid is 1:2:(0.9-2):(1.5-8.5), and the molar ratio of mercaptocarboxylic acid to allyl glycidyl ether is 1:

1.

4. The high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material according to claim 3, characterized in that, The diamino compound is one or more of 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 2,2'-diaminodiphenyl sulfide, and 4,4'-diaminodiphenyl sulfide; the triacid anhydride compound is trimellitic anhydride or 1,2,4-cyclohexanetricarboxylic anhydride; and the thiocarboxylic acid is one or two of mercaptopropionic acid and mercaptoacetic acid.

5. The high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material according to claim 3, characterized in that, The dehydrating agent is one or both of toluene and xylene, and its mass is 0.5 to 5 times that of tris(2-hydroxyethyl) isocyanurate; the organic solvent is one or more of tetrahydrofuran, 1,4-dioxane, ethyl acetate, acetone, chloroform, N,N-dimethylformamide, and dichloromethane, and its mass is 10 to 30 times that of tris(2-hydroxyethyl) isocyanurate; the photoinitiator is one or more of 4-dimethylaminopyridine, benzophenone, p-aminoacetone, 2,2-dimethoxy-2-phenylacetophenone, and 1-hydroxycyclohexylphenyl ketone, and its mass is 0.4% to 2% of the mass of allyl glycidyl ether.

6. The high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material according to claim 1, characterized in that, The mass ratio of the carbon fiber cloth, the biodegradable imide skeleton hyperbranched epoxy resin, and the bisphenol A type epoxy resin is 1:(0.1-0.2):(0.2-0.5).

7. A method for preparing a high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material according to any one of claims 1-6, characterized in that, Includes the following steps: The carbon fiber cloth is completely immersed in a mixed solution of end-thiol hyperbranched polymer, organic solvent, and photoinitiator, and irradiated with ultraviolet light at a power of 400W-800W for 20-60 minutes to carry out a thiol-olefin click reaction. After the reaction is completed, the carbon fiber cloth is removed and dried at 80-100℃ for 5-15 hours to obtain surface-functionalized carbon fiber cloth. The surface-functionalized carbon fiber cloth is placed in a mold, and a mixture of biodegradable imide skeleton hyperbranched epoxy resin, bisphenol A type epoxy resin, and curing agent is uniformly coated on the surface-functionalized carbon fiber cloth. It is then hot-pressed and cured at 2-10MPa and 100-180℃ for 1-3 hours. After hot pressing, heating is stopped, and lamination is performed at 5-15MPa for 10-20 minutes. Then, the temperature is lowered to below 80℃, and the cloth is removed to obtain a high-performance biodegradable imide skeleton hyperbranched epoxy resin / carbon fiber composite material. The number-average molecular weight of the terminal thiol hyperbranched polymer is 1300-16000 g / mol, the number-average molecular weight of the biodegradable imide skeleton hyperbranched epoxy resin is 1500-19000 g / mol, the epoxy value is 0.10-0.25 mol / 100g, and the shape factor is 0.97-2.

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8. The method for preparing the high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material according to claim 7, characterized in that, The mass ratio of the surface-functionalized carbon fiber cloth, the biodegradable imide skeleton hyperbranched epoxy resin, the bisphenol A type epoxy resin, and the curing agent is 1:(0.1~0.2):(0.2~0.5):(0.05~0.1).

9. The method for preparing the high-performance biodegradable imide-backbone hyperbranched epoxy resin / carbon fiber composite material according to claim 7, characterized in that, The carbon fiber cloth is one of commercially available T300, T700, and T800; the photoinitiator is one or more of 4-dimethylaminopyridine, benzophenone, p-aminoacetone, 2,2-dimethoxy-2-phenylacetophenone, and 1-hydroxycyclohexylphenyl ketone, with a mass of 0.5% to 3% of the carbon fiber cloth; the organic solvent is tetrahydrofuran, 1,4-dioxane, ethyl acetate, acetone, chloroform, N,N-dimethylformamide, and dichloromethane. One or more of the following, wherein the mass of the polymer is 0.5 to 30 times the mass of the carbon fiber cloth; the mass of the terminal thiol hyperbranched polymer is 0.5 to 2.0 times the mass of the carbon fiber cloth; the type of bisphenol A epoxy resin is E51; the curing agent is one or more of 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 2,2'-diaminodiphenyl sulfide, and 4,4'-diaminodiphenyl sulfide.

10. A method for degrading and recycling the high-performance biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composite material according to any one of claims 1-6 or the high-performance biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composite material prepared by the preparation method according to any one of claims 7-9, characterized in that, Includes the following steps: A biodegradable imide-backed hyperbranched epoxy resin / carbon fiber composite material is immersed in an alkaline alcohol solution and degraded at 130-180℃ for 2-12 hours to obtain carbon fiber cloth and degradation solution; the carbon fiber cloth is washed with acetone and dried at 50-70℃ for 10-24 hours to obtain recycled carbon fiber cloth; then the recycled carbon fiber cloth is used to replace the carbon fiber cloth for recycling according to the preparation method of any one of claims 7-9. The concentration of the alkaline alcohol solution is 0.10-1.50 mol / L, and the alkaline alcohol solution is an alcohol solution of potassium hydroxide and / or sodium hydroxide, wherein the alcohol in the alkaline alcohol solution is methanol and / or ethanol.

11. The degradation and recycling method according to claim 10, characterized in that, The alcohol content in the alkaline alcohol solution is 90%-100% by mass.

12. The degradation and recycling method according to claim 10, characterized in that, The mass ratio of the biodegradable imide skeleton hyperbranched epoxy resin / carbon fiber composite material to the alkaline alcohol solution is (3-5):(10-20).

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