Degradable epoxy resin composition, degradable epoxy resin material as well as preparation method, degradation method and application of degradable epoxy resin material

Abstract

The invention relates to the technical field of epoxy resin, in particular to a degradable epoxy resin composition, a degradable epoxy resin material and a preparation method, a degradation method and application of the degradable epoxy resin composition and the degradable epoxy resin material. The degradable epoxy resin composition comprises a component A and a component B, the component A comprises degradable epoxy resin containing a Schiff base structure; the degradable epoxy resin monomer containing the Schiff base structure comprises a compound shown in a formula (I); the component B comprises a degradable curing agent containing the Schiff base structure; the degradable curing agent containing the Schiff base structure comprises a compound as shown in a formula (II); r < 11 >, R < 22 > and R < 23 > are respectively and independently selected from C3-C20 cycloalkylene; and R < 12 >, R < 13 > and R < 21 > are respectively and independently selected from arylene groups with 6 to 30 carbon atoms. Resin prepared from the degradable epoxy resin composition has excellent mechanical properties and can be completely degraded under mild conditions.

Description

Biodegradable epoxy resin compositions, biodegradable epoxy resin materials, their preparation methods, degradation methods, and applications. Technical Field

[0001] This application relates to the field of epoxy resin technology, and in particular to biodegradable epoxy resin compositions, biodegradable epoxy resin materials, their preparation methods, degradation methods and applications. Background Technology

[0002] Wind power generation is a renewable energy source that converts the kinetic energy of wind into electrical energy, primarily achieved through wind turbine generators. The principle of wind power generation is to use wind power to drive the rotation of wind turbine blades, which in turn drives a generator to produce electricity. The matrix of the blades is mainly epoxy resin composite material. Epoxy resin systems have good mechanical properties, chemical corrosion resistance, and dimensional stability, which helps ensure the blades' operational efficiency and service life in harsh environments. Traditional epoxy resin, after curing, forms a permanently cross-linked structure, making it difficult to reprocess or recycle, and the disposal of waste epoxy resin has become a problem. Currently, commonly used disposal methods include incineration, landfill, and chemical treatment, but all of these inevitably lead to environmental problems.

[0003] The development of dynamic covalent bond technology has provided a new approach to solving the above problems. By introducing dynamic bonds into epoxy resins or curing agents, recyclable epoxy resin composites can be prepared. However, when the content of dynamic covalent bonds is high, it will affect the overall performance of the epoxy resin system to a certain extent, such as mechanical properties and heat resistance. When the content of dynamic covalent bonds is low, the recycling effect of epoxy resin is not ideal, and the cured product is difficult to completely degrade.

[0004] Therefore, it is necessary to develop a biodegradable epoxy resin compound with an appropriate dynamic covalent bond content to match the comprehensive performance and biodegradability required by the blades, so as to meet the needs of wind turbine blade use while achieving the recycling requirements of blade waste. Summary of the Invention

[0005] Based on this, one or more embodiments of this application provide biodegradable epoxy resin compositions, methods for their preparation, and applications. The resins prepared from the biodegradable epoxy resin compositions of this application possess excellent mechanical properties and are capable of complete degradation under mild conditions.

[0006] The technical solution of this application includes the following:

[0007] In a first aspect, this application provides a biodegradable epoxy resin composition, the composition comprising component A and component B;

[0008] Component A includes a biodegradable epoxy resin monomer containing a Schiff base structure;

[0009] The biodegradable epoxy resin monomer containing a Schiff base structure includes compounds represented by formula (I):

[0010] (I);

[0011] Component B includes a biodegradable curing agent containing a Schiff base structure;

[0012] The biodegradable curing agent containing a Schiff base structure includes the compound shown in formula (II):

[0013] (II);

[0014] R 11 R 22 and R 23 Each is independently selected from C3-C20 cycloalkylene groups;

[0015] R 12 R 13 and R 21 They were each independently selected from C6-C30 arylene groups.

[0016] Furthermore, R 11 R 22 and R 23 Each is independently selected from C6-C18 cycloalkylene groups;

[0017] R 12 R 13 and R 21 They were each independently selected from C6-C10 arylene groups.

[0018] Furthermore, R 11 R 22 and R 23 Selected independently from:

[0019] , , , ;

[0020] R 12 R 13 and R 21 Selected independently ;

[0021] R 31 R 32 R 33 R 34 and R 35 Each is independently selected from hydrogen or C1-C9 alkyl groups.

[0022] In some embodiments, the method for preparing the biodegradable epoxy resin containing a Schiff base structure includes the following steps:

[0023] The intermediate compound was prepared by reacting diamine compound A with a hydroxyl compound.

[0024] The structure of the diamine compound A is as follows: ;

[0025] The structure of the intermediate compound is as follows: ;

[0026] R 41 R 42 and R 43 respectively with R 11 R 12 and R 13 The definitions are the same;

[0027] The intermediate compound is reacted with epichlorohydrin to prepare the biodegradable epoxy resin containing a Schiff base structure; and / or,

[0028] The preparation method of the biodegradable curing agent containing a Schiff base structure includes the following steps:

[0029] The diamine compound B was reacted with an aldehyde compound to prepare the biodegradable curing agent containing a Schiff base structure.

[0030] The structure of the diamine compound B is as follows: ;R 51 With R 21 The definitions are the same.

[0031] Further, component A comprises, by weight, 10-40 parts of glycidyl ether epoxy resin monomer and 60-100 parts of degradable epoxy resin monomer containing a Schiff base structure; and / or,

[0032] Component B, by weight, comprises 10-20 parts of a diamine compound C and 80-100 parts of a degradable curing agent containing a Schiff base structure;

[0033] The structure of the diamine compound C is as follows: ;R 61 Selected from C3-C20 cycloalkylene compounds.

[0034] Furthermore, the molar ratio of component A to component B is 2:(1-1.2).

[0035] Secondly, this application provides the application of the biodegradable epoxy resin composition described above in the preparation of wind turbine blades.

[0036] Thirdly, this application provides a method for preparing a biodegradable epoxy resin material, which is prepared using the biodegradable epoxy resin composition described above, and includes the following steps:

[0037] Component A and component B are mixed, and the resulting mixture is poured into a mold, heated at a first temperature for a first time, and then heated at a second temperature for a second time to obtain the biodegradable resin cured product.

[0038] The first temperature is 40℃-60℃, and the first time is 3h-5h;

[0039] The second temperature is 70℃-80℃, and the second time is 6h-12h.

[0040] Fourthly, this application provides a biodegradable epoxy resin material, which is prepared using the preparation method described above.

[0041] Fifthly, this application provides a method for degrading the biodegradable epoxy resin material described above, comprising the following steps:

[0042] The biodegradable epoxy resin material is crushed to obtain block-shaped material;

[0043] The block was immersed in an acidic degradation solution and stirred at a third temperature, which was 90°C-110°C.

[0044] The acidic degradation solution comprises acid and solvent;

[0045] Optionally, the acid includes at least one selected from hydrochloric acid, sulfuric acid, nitric acid, acetic acid, trifluoroacetic acid, methanesulfonic acid, hydrobromic acid, hydrofluoric acid, lactic acid, formic acid, benzoic acid, and salicylic acid.

[0046] Optionally, the solvent includes at least one selected from water, alcohol, dichloromethane, chloroform, benzene, toluene, xylene, acetate, tetrahydrofuran, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0047] Compared with the prior art, this application has at least the following beneficial effects:

[0048] (1) This application introduces a specific degradable Schiff base structure into both component A (epoxy resin component) and component B (curing agent component), which makes the raw materials of the epoxy resin cured product readily available and stable, while also giving the thermosetting epoxy resin cured product degradability.

[0049] (2) The biodegradable epoxy resin composition of this application is applicable to currently used epoxy resin systems and can be cured using existing epoxy resin curing processes.

[0050] (3) The biodegradable epoxy resin material of this application not only achieves biodegradability but also retains the good mechanical properties of epoxy resin, including tensile, bending and impact resistance, and has high strength, high modulus and high heat resistance, and can maintain performance stability under complex environmental conditions.

[0051] (4) The degradation conditions of the biodegradable epoxy resin material of this application are mild, and complete degradation can be achieved by heating and stirring in an acidic degradation solution. Detailed Implementation

[0052] The present application is further described below with reference to embodiments and examples. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the application. Furthermore, it should be understood that after reading the teachings of this application, those skilled in the art can make various alterations or modifications to this application, and these equivalent forms also fall within the protection scope of the appended claims.

[0053] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0054] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more than or equal to two.

[0055] In this application, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.

[0056] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0057] In this application, terms such as "preferred," "better," "more suitable," and "ideal" are used only to describe implementation methods or embodiments with better effects, and should be understood not to constitute a limitation on the scope of protection of this application.

[0058] In this application, terms such as "further," "even further," and "particularly" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0059] In this application, the terms "optionally," "optionally," and "optional" refer to options that are optional, meaning they can be selected from either "with" or "without." If multiple "optional" options appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" option is independent.

[0060] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers to an integer within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0061] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0062] In this application, percentage content refers to mass percentage for solid-liquid mixtures and solid-phase-solid mixtures, and volume percentage for liquid-phase-liquid mixtures, unless otherwise specified.

[0063] In this application, unless otherwise specified, percentage concentrations refer to final concentrations. The final concentration refers to the percentage of the added component in the system after its addition.

[0064] In this application, "alkyl" refers to a saturated hydrocarbon containing a primary (normal) carbon atom, or a secondary carbon atom, or a tertiary carbon atom, or a quaternary carbon atom, or a combination thereof. Phrases containing this term, such as "C1-C9 alkyl," refer to alkyl groups containing 1-9 carbon atoms, and each occurrence can independently be C1 alkyl, C2 alkyl, C3 alkyl, C4 alkyl, C5 alkyl, C6 alkyl, C7 alkyl, C8 alkyl, or C9 alkyl. Suitable examples include, but are not limited to: methyl (Me, -CH3), ethyl (Et, -CH2CH3), 1-propyl (n-Pr, n-propyl, -CH2CH2CH3), 2-propyl (i-Pr, i-propyl, -CH(CH3)2), 1-butyl (n-Bu, n-butyl, -CH2CH2CH2CH3), 2-methyl-1-propyl (i-Bu, i-butyl, -CH2CH(CH3)2), 2-butyl (s-Bu, s-butyl, -CH(C H3)CH2CH3), 2-methyl-2-propyl (t-Bu, t-butyl, -C(CH3)3), 1-pentyl (n-pentyl, -CH2CH2CH2CH2CH3), 2-pentyl (-CH(CH3)CH2CH2CH3), 3-pentyl (-CH(CH2CH3)2), 2-methyl-2-butyl (-C(CH3)2CH2CH3), 3-methyl-2-butyl (-CH(CH3)CH(CH3)2), 3-methyl-1-butyl (- CH2CH2CH(CH3)2), 2-methyl-1-butyl(-CH2CH(CH3)CH2CH3), 1-hexyl(-CH2CH2CH2CH2CH2CH3), 2-hexyl(-CH(CH3)CH2CH2CH2CH3), 3-hexyl(-CH(CH2CH3)(CH2CH2CH3)), 2-methyl-2-pentyl(-C(CH3)2CH2CH2CH3), 3-methyl-2-pentyl(-CH(CH3)CH( CH3)CH2CH3), 4-methyl-2-pentyl (-CH(CH3)CH2CH(CH3)2), 3-methyl-3-pentyl (-C(CH3)(CH2CH3)2), 2-methyl-3-pentyl (-CH(CH2CH3)CH(CH3)2), 2,3-dimethyl-2-butyl (-C(CH3)2CH(CH3)2), 3,3-dimethyl-2-butyl (-CH(CH3)C(CH3)3 and octyl (-(CH2)7CH3).

[0065] In this application, "cycloalkyl" refers to a non-aromatic hydrocarbon containing a ring of carbon atoms, which can be monocycloalkyl, spirocycloalkyl, or bridged cycloalkyl. Phrases containing this term, such as "C3-C20 cycloalkyl," refer to cycloalkyl compounds containing 3-20 carbon atoms, and each occurrence can independently be C3, C4, C5, C6, C7, C8, C9, C10, C11, C12, C13, C14, C15, C16, C17, C18, C19, or C20 cycloalkyl. Suitable examples include, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, and cycloheptyl. Additionally, "cycloalkyl" may also contain one or more double bonds; representative examples of cycloalkyl compounds containing double bonds include cyclopentenyl, cyclohexenyl, cyclohexadienyl, and cyclobutadienyl. "Cycloalkylene" refers to a hydrocarbon group derived from "cycloalkyl" by removing one hydrogen atom, resulting in a group with two monovalent groups. Suitable examples include, but are not limited to: cyclopropylene, cyclobutylene, cyclopentylene, cyclohexylene, cycloheptylene, cyclopentenylene, cyclohexenylene, hexadienylene, and butadienylene. , , , , etc.; preferably or .

[0066] In this application, "aryl" refers to an aromatic hydrocarbon group derived from an aromatic ring compound by removing one hydrogen atom. It can be a monocyclic aryl, a fused-ring aryl, or a polycyclic aryl. For polycyclic rings, at least one is an aromatic ring system. Phrases containing this term, such as "C6-C30," refer to an aryl group containing 6 to 30 atoms, and each occurrence can independently be a C6 aryl, C10, C20, C30 aryl, etc. Suitable examples include, but are not limited to, benzene and naphthalene. "Arylidene" refers to an aromatic hydrocarbon group derived from an "aryl" compound by removing one hydrogen atom. Suitable examples include, but are not limited to, […]. , , or Preferred .

[0067] In this application, " " " indicates a connection point.

[0068] In a first aspect, this application provides a biodegradable epoxy resin composition, the composition comprising component A and component B;

[0069] Component A includes a biodegradable epoxy resin monomer containing a Schiff base structure;

[0070] Degradable epoxy resin monomers containing Schiff base structures include compounds represented by formula (I):

[0071] (I);

[0072] Component B includes a biodegradable curing agent containing a Schiff base structure;

[0073] Degradable curing agents containing Schiff base structures include compounds represented by formula (II):

[0074] (II);

[0075] R 11 R 22 and R 23 Each is independently selected from C3-C20 cycloalkylene groups;

[0076] R 12 R 13 and R 21 They were each independently selected from C6-C30 arylene groups.

[0077] This application introduces a specific degradable Schiff base structure into both component A (epoxy resin component) and component B (curing agent component), resulting in a epoxy resin cured product with readily available raw materials and good stability, while also imparting degradability to the thermosetting epoxy resin cured product.

[0078] Furthermore, R 11 R 22 and R 23 Each is independently selected from C6-C18 cycloalkylene groups;

[0079] R 12 R 13 and R 21 They were each independently selected from C6-C10 arylene groups.

[0080] Furthermore, R 11 R 22 and R 23 Selected independently from:

[0081] , , , ;

[0082] R 12 R 13 and R 21 Selected independently ;

[0083] R 31 R 32R 33 R 34 and R 35 Each is independently selected from hydrogen or C1-C9 alkyl groups.

[0084] In some embodiments, R 11 R 22 and R 23 Selected independently from: , , , ,or Preferred or .

[0085] In some embodiments, R 12 R 13 and R 21 Selected independently , , or Preferred .

[0086] In some embodiments, the preparation method of a biodegradable epoxy resin containing a Schiff base structure includes the following steps:

[0087] The intermediate compound was prepared by reacting diamine compound A with a hydroxyl compound.

[0088] The structure of diamine compound A is as follows: ;

[0089] The structure of the intermediate compound is ;

[0090] R 41 R 42 and R 43 respectively with R 11 R 12 and R 13 The definitions are the same;

[0091] The intermediate compound was reacted with epichlorohydrin to prepare a biodegradable epoxy resin containing a Schiff base structure; and / or,

[0092] The preparation method of a biodegradable curing agent containing a Schiff base structure includes the following steps:

[0093] A diamine compound B was reacted with an aldehyde compound to prepare a biodegradable curing agent containing a Schiff base structure.

[0094] The structure of diamine compound B is as follows: ;R 51 With R 21The definitions are the same.

[0095] In the above preparation method, during the reaction of diamine compound A with an aldehyde compound, the amino group of diamine compound A and the aldehyde group of the aldehyde compound condense to form an imine, yielding an intermediate compound. The structure of the aldehyde compound can be confirmed by the structures of diamine compound A and the intermediate compound, therefore no further limitations are imposed. Similarly, during the reaction of diamine compound B with an aldehyde compound, the amino group of diamine compound B and the aldehyde group of the aldehyde compound condense to form an imine, yielding a biodegradable curing agent containing a Schiff base structure. The structure of the aldehyde compound can be confirmed by the structures of diamine compound B and the biodegradable curing agent containing a Schiff base structure, therefore no further limitations are imposed.

[0096] Optionally, diamine compound A and diamine compound B each independently include at least one of 4,4'-diaminodicyclohexylmethane, isophorone diamine, 1,3-cyclohexanedimethylamine, 1-methyl-2,4-cyclohexanediamine, and 1,2-cyclohexanediamine.

[0097] Optionally, the hydroxyaldehyde compounds include at least one of p-hydroxybenzaldehyde, m-hydroxybenzaldehyde, 3-hydroxypropionaldehyde, and 4-hydroxy-3-methylbenzaldehyde.

[0098] Optionally, the aldehyde compounds include at least one of terephthalaldehyde, isophthalaldehyde, and o-phthalaldehyde.

[0099] Further, component A comprises, by weight, 10-40 parts of glycidyl ether epoxy resin monomer and 60-100 parts of degradable epoxy resin monomer containing a Schiff base structure; and / or,

[0100] Component B, by weight, comprises 10-20 parts of diamine compound C and 80-100 parts of a biodegradable curing agent containing a Schiff base structure;

[0101] The structure of diamine compound C is as follows: ;R 61 Selected from C3-C20 cycloalkylene compounds.

[0102] Component A uses a combination of glycidyl ether epoxy resin monomers and biodegradable epoxy resin monomers containing Schiff base structures to increase the density of biodegradable Schiff base structures, thereby better achieving the degradation of epoxy resin cured products; Component B uses a combination of diamine compound C and biodegradable curing agent containing Schiff base structures to increase the content of rigid structures, thereby better improving the glass transition temperature and mechanical properties of the material.

[0103] In some embodiments, component A comprises, by weight percentage, 10%-30% of glycidyl ether epoxy resin monomers and 70%-90% of degradable epoxy resin monomers containing Schiff base structures.

[0104] In some embodiments, component B comprises, by weight percentage, 10%-30% of a diamine compound C and 70%-90% of a degradable curing agent containing a Schiff base structure.

[0105] Preferably, R 61 Selected from C6-C18 cycloalkylene compounds.

[0106] In some embodiments, R 61 Selected from: , , , Furthermore, R 61 Selected from: , , , ,or Preferred or .

[0107] Optionally, the glycidyl ether epoxy resin monomer includes at least one of bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, and bisphenol S diglycidyl ether.

[0108] Optionally, the diamine compound C includes at least one selected from 4,4'-diaminodicyclohexylmethane, isophorone diamine, 1,3-cyclohexanedimethylamine, 1-methyl-2,4-cyclohexanediamine, and 1,2-cyclohexanediamine.

[0109] In some embodiments, the molar ratio of component A to component B is 2:(1-1.2). The molar ratio is defined as the ratio of the sum of the moles of all monomers contained in component A to the sum of the moles of all monomers contained in component B.

[0110] Secondly, this application provides the application of the aforementioned biodegradable epoxy resin composition in the preparation of wind turbine blades. The biodegradable epoxy resin material of this application achieves biodegradability while retaining the excellent mechanical properties of epoxy resin, including tensile, flexural, and impact resistance. It possesses high strength, high modulus, and high heat resistance, and can maintain performance stability under complex environmental conditions. The biodegradable epoxy resin composition with the above advantages, when used in wind turbine blades, can improve the service life of the blades and ensure the stability of their mechanical properties. Furthermore, the biodegradable epoxy resin material prepared therefrom can achieve complete degradation under mild conditions, meeting the requirements for wind turbine blade use while also achieving the recycling of blade waste.

[0111] Thirdly, this application provides a method for preparing a biodegradable epoxy resin material, which is prepared using the biodegradable epoxy resin composition described above, and includes the following steps:

[0112] Component A and component B are mixed, and the resulting mixture is poured into a mold. The mixture is heated at a first temperature for a first time, and then heated at a second temperature for a second time to obtain a biodegradable resin cured product.

[0113] The first temperature is 40℃-60℃, and the first time is 3h-5h;

[0114] The second temperature is 70℃-80℃, and the second time is 6h-12h.

[0115] The biodegradable epoxy resin composition of this application is applicable to currently used epoxy resin systems and can be cured using existing epoxy resin curing processes.

[0116] Fourthly, this application provides a biodegradable epoxy resin material, which is prepared using the preparation method described above.

[0117] Fifthly, this application provides a method for degrading the biodegradable epoxy resin material described above, comprising the following steps:

[0118] The biodegradable epoxy resin material is crushed to obtain block-shaped material;

[0119] The block was immersed in an acidic degradation solution and stirred at a third temperature, which was 90℃-110℃.

[0120] The acidic degradation solution consists of acid and solvent;

[0121] Optionally, the acid includes at least one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, trifluoroacetic acid, methanesulfonic acid, hydrobromic acid, hydrofluoric acid, lactic acid, formic acid, benzoic acid, and salicylic acid;

[0122] Optionally, the solvent includes at least one selected from water, alcohol, dichloromethane, chloroform, benzene, toluene, xylene, acetate, tetrahydrofuran, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

[0123] The degradation conditions of the biodegradable epoxy resin material of this application are mild, and complete degradation can be achieved by heating and stirring in an acidic degradation solution.

[0124] The following are some specific examples.

[0125] For experimental parameters not specified in the following specific embodiments, please refer to the guidelines given in this application document first, or refer to experimental manuals or other experimental methods known in the art, or refer to the experimental conditions recommended by the manufacturer.

[0126] The raw materials and reagents involved in the following specific embodiments can be obtained commercially or prepared by those skilled in the art using known methods.

[0127] Example 1

[0128] This embodiment provides a method for preparing and degrading a biodegradable epoxy resin material, including the following steps:

[0129] (1) Preparation of component A1

[0130] Preparation of a biodegradable resin containing a Schiff base structure: 210 g of 4,4'-diaminodicyclohexylmethane and 244 g of p-hydroxybenzaldehyde were dissolved in anhydrous ethanol and transferred to a three-necked flask equipped with a reflux condenser. The mixture was heated and stirred at 50 °C for 2 h. The precipitated solid powder was separated by filtration and washed with anhydrous ethanol, followed by heating in an oven for 1 h. The reaction product was added to the three-necked flask along with 184 g of epichlorohydrin and 3-5 drops of tetrabutylammonium bromide. The mixture was heated and stirred at 100 °C for 24 h. After the reaction was complete, a 40 wt% sodium hydroxide aqueous solution was slowly added. After the liquid completely separated into layers, the lower oil phase was collected to obtain a biodegradable epoxy resin containing a Schiff base structure, with the structure shown in formula (I-1).

[0131] (I-1);

[0132] The biodegradable epoxy resin I-1 was subjected to 1H NMR spectroscopy (NMR spectroscopy). 1 Characterized by H-NMR, its chemical structure was confirmed as follows: 1 H-NMR (MHz, DMSO-d6, ppm): 0.81-1.22, 1.42-1.86 (m, 20H, Cyh-H); 2.56 (m, 2H, Cyh-CH2-); 2.61 (m, 4 H, O-CH2-); 2.71 (m, 4H, Ar-CH2-); 3.14 (s, 2H, O-CH-); 6.60-7.50 (m, 8H, Ar-H); 8.05 (s, 2H, -CH=N).

[0133] 20g of bisphenol A diglycidyl ether monomer ( ) and 80g of biodegradable epoxy resin (I-1) containing Schiff base structure are mixed and stirred evenly to obtain component A1.

[0134] (2) Preparation of component B1

[0135] Preparation of a biodegradable epoxy resin containing a Schiff base structure: 210 g of 4,4'-diaminodicyclohexylmethane and 67 g of terephthalaldehyde were dissolved in anhydrous ethanol and transferred to a three-necked flask equipped with a reflux condenser. The mixture was heated and stirred at 50 °C for 2 h. The solid powder precipitated from the solution was separated by filtration and washed with anhydrous ethanol. Subsequently, the mixture was heated in an oven for 1 h to prepare a biodegradable curing agent containing a Schiff base structure, with the structure shown in formula (Ⅱ-1).

[0136] (Ⅱ-1);

[0137] The biodegradable curing agent I was subjected to 1H NMR spectroscopy ( 1 Characterized by H-NMR, its chemical structure was confirmed as follows: 1 H-NMR (MHz, DMSO-d6, ppm): 0.80-1.25, 1.40-1.85 (m, 40H, Cyh-H); 1.66 (m, 4H, -NH2); 2.65 (m, 4H, Cyh-CH2-); 6.60-7.50 (m, 4H, Ar-H); 8.06 (s, 2H, -CH=N).

[0138] 20g of 4,4'-diaminodicyclohexylmethane ( ) and 80g of a degradable curing agent (Ⅱ-1) containing a Schiff base structure are mixed and stirred evenly to obtain component B1.

[0139] (3) Preparation of biodegradable epoxy resin materials

[0140] The above-prepared components A1 and B1 were mixed in a molar ratio of 2:1.1 and stirred evenly. The mixture was poured into a metal mold and cured at 50°C for 4 hours, then heated to 75°C and cured for 8 hours to obtain biodegradable epoxy resin material I.

[0141] (4) Degradation of biodegradable epoxy resin materials

[0142] The biodegradable epoxy resin material I was broken into small pieces and soaked in an acidic degradation solution of sulfuric acid and tetrahydrofuran (1:1). The solution was heated and stirred at 100°C until the biodegradable epoxy resin cured product was completely dissolved. Then, the biodegradable epoxy resin and degradation solution were obtained by rotary evaporation.

[0143] Example 2

[0144] This embodiment provides a method for preparing and degrading a biodegradable epoxy resin material, including the following steps:

[0145] (1) Preparation of component A2

[0146] Preparation of a biodegradable epoxy resin containing a Schiff base structure: 170 g of isoflurane diamine and 244 g of p-hydroxybenzaldehyde were dissolved in anhydrous ethanol and transferred to a three-necked flask equipped with a reflux condenser. The mixture was heated and stirred at 50 °C for 2 h. The precipitated solid powder was separated by filtration and washed with anhydrous ethanol, followed by heating in an oven for 1 h. The reaction product was added to the three-necked flask along with 184 g of epichlorohydrin and 3-5 drops of tetrabutylammonium bromide. The mixture was heated and stirred at 100 °C for 24 h. After the reaction was complete, a 40 wt% sodium hydroxide aqueous solution was slowly added. After the liquid completely separated into layers, the lower oil phase was collected to obtain the biodegradable epoxy resin containing a Schiff base structure, with the structure shown in formula (I-2).

[0147] (I-2);

[0148] The biodegradable epoxy resin II was subjected to 1H NMR spectroscopy ( 1 Characterized by H-NMR, its chemical structure was confirmed as follows: 1 H-NMR (MHz, DMSO-d6, ppm): 0.85-1.20 (m, 9H, -CH3); 1.21-2.10, 2.65-2.81 (m, 7H, Cyh-H); 2.66 (m, 4H, O-CH2-); 2.71 (m, 4H, Ar-CH2-); 2.77 (m, 2H, -CH2-); 3.14 (s, 2H, O-CH-); 6.60-7.50 (m, 8H, Ar-H); 8.10 (s, 2H, -CH=N).

[0149] 20g of bisphenol F diglycidyl ether monomer ( ) and 80g of biodegradable epoxy resin (I-2) containing Schiff base structure are mixed and stirred evenly to obtain component A2.

[0150] (2) Preparation of component B2

[0151] Preparation of a biodegradable epoxy resin containing a Schiff base structure: 170 g of isoflurane diamine and 67 g of terephthalaldehyde were dissolved in anhydrous ethanol and transferred to a three-necked flask equipped with a reflux condenser. The mixture was heated and stirred at 50 °C for 2 h. The solid powder precipitated from the solution was separated by filtration and washed with anhydrous ethanol. Subsequently, the mixture was heated in an oven for 1 h to prepare a biodegradable curing agent containing a Schiff base structure, with the structure shown in formula (Ⅱ-2).

[0152] (Ⅱ-2);

[0153] The biodegradable curing agent II was subjected to 1H NMR spectroscopy ( 1 Characterized by H-NMR, its chemical structure was confirmed as follows: 1H-NMR (MHz, DMSO-d6, ppm): 0.85-1.20 (m, 18H, -CH3); 1.21-2.10, 2.65-2.81 (m, 14H, Cyh-H); 1.45 (m, 4H, -NH2); 2.77 (m, 4H, -CH2-); 6.60-7.50 (m, 4H, Ar-H); 8.10 (s, 2H, -CH=N).

[0154] 20g of isoflurane diamine ( Mix 80g of a degradable curing agent (Ⅱ-2) containing a Schiff base structure with the curing agent and stir until homogeneous to obtain curing agent component B2.

[0155] (3) Preparation of biodegradable epoxy resin materials

[0156] The above-prepared components A2 and B2 were mixed in a molar ratio of 2:1.1 and stirred evenly. The mixture was poured into a metal mold and cured at 50°C for 4 hours, then heated to 75°C and cured for 8 hours to obtain the biodegradable epoxy resin cured product II.

[0157] (4) Degradation of biodegradable epoxy resin materials

[0158] The biodegradable epoxy resin cured product II was broken into small pieces and soaked in an acidic degradation solution of sulfuric acid and tetrahydrofuran (1:1). The solution was heated and stirred at 100°C until the biodegradable epoxy resin cured product was completely dissolved. Then, the biodegradable epoxy resin and degradation solution were separated by rotary evaporation.

[0159] Example 3

[0160] This embodiment provides a method for preparing and degrading a biodegradable epoxy resin material, including the following steps:

[0161] (1) Preparation of component A3

[0162] A biodegradable epoxy resin (I-2) containing a Schiff base structure was prepared using the same method as in Example 2, and was directly used as epoxy resin component A3.

[0163] (2) Preparation of component B3

[0164] A biodegradable curing agent (II-2) containing a Schiff base structure was prepared using the same method as in Example 2. 20 g of isoflurane diamine and 80 g of the biodegradable curing agent II-2 containing a Schiff base structure were mixed and stirred until homogeneous to obtain curing agent component B3.

[0165] (3) Preparation of biodegradable epoxy resin materials

[0166] The above-prepared components A3 and B3 were mixed in a molar ratio of 2:1.1 and stirred evenly. The mixture was poured into a metal mold and cured at 50°C for 4 hours, then heated to 75°C and cured for 8 hours to obtain the biodegradable epoxy resin cured product III.

[0167] (4) Degradation of biodegradable epoxy resin materials

[0168] The biodegradable epoxy resin cured product III was broken into small pieces and soaked in an acidic degradation solution of sulfuric acid and tetrahydrofuran (1:1). The solution was heated and stirred at 100°C until the biodegradable epoxy resin cured product was completely dissolved. Then, the biodegradable epoxy resin and degradation solution were separated by rotary evaporation.

[0169] Example 4

[0170] This embodiment provides a method for preparing and degrading a biodegradable epoxy resin material, including the following steps:

[0171] (1) Preparation of component A4

[0172] A biodegradable epoxy resin (I-2) containing a Schiff base structure was prepared using the same method as in Example 2. 20 g of bisphenol F diglycidyl ether and 80 g of the biodegradable epoxy resin (I-2) containing a Schiff base structure were mixed and stirred until homogeneous to obtain epoxy resin component A4.

[0173] (2) Preparation of component B4

[0174] A biodegradable curing agent (II-2) containing a Schiff base structure was prepared using the same method as in Example 2. It was used directly as epoxy resin component B4.

[0175] (3) Preparation of biodegradable epoxy resin materials

[0176] The above-prepared components A4 and B4 were mixed in a molar ratio of 2:1.1 and stirred evenly. The mixture was poured into a metal mold and cured at 50°C for 4 hours, then heated to 75°C and cured for 8 hours to obtain the biodegradable epoxy resin cured product IV.

[0177] (4) Degradation of biodegradable epoxy resin materials

[0178] The biodegradable epoxy resin cured product IV was broken into small pieces and soaked in an acidic degradation solution of sulfuric acid and tetrahydrofuran (1:1). The solution was heated and stirred at 100°C until the biodegradable epoxy resin cured product was completely dissolved. Then, the biodegradable epoxy resin and degradation solution were separated by rotary evaporation.

[0179] Example 5

[0180] This embodiment provides a method for preparing and degrading a biodegradable epoxy resin material, including the following steps:

[0181] (1) Preparation of component A5

[0182] A biodegradable epoxy resin (I-2) containing a Schiff base structure was prepared using the same method as in Example 2. It was used directly as epoxy resin component A5.

[0183] (2) Preparation of component B5

[0184] A biodegradable curing agent (II-2) containing a Schiff base structure was prepared using the same method as in Example 2. It was used directly as curing agent component B5.

[0185] (3) Preparation of biodegradable epoxy resin materials

[0186] The components A5 and B5 prepared above are mixed in equal amounts and stirred evenly. The mixture is poured into a metal mold and cured at 50°C for 4 hours, then heated to 75°C and cured for 8 hours to obtain the biodegradable epoxy resin cured product V.

[0187] (4) Degradation of biodegradable epoxy resin materials

[0188] The biodegradable epoxy resin cured product V was broken into small pieces and soaked in an acidic degradation solution of sulfuric acid and tetrahydrofuran (1:1). The solution was heated and stirred at 100°C until the biodegradable epoxy resin cured product was completely dissolved. Then, the biodegradable epoxy resin and degradation solution were obtained by rotary evaporation.

[0189] Comparative Example 1

[0190] This comparative example provides another method for preparing and degrading a biodegradable epoxy resin material, including the following steps:

[0191] Bisphenol A diglycidyl ether and 4,4'-diaminodicyclohexylmethane were mixed in equal proportions and stirred. The mixture was poured into a metal mold and cured at 50°C for 4 hours, then heated to 75°C and cured for another 8 hours to obtain epoxy resin cured product VI. Epoxy resin cured product VI was broken into small pieces and soaked in an acidic degradation solution of sulfuric acid and tetrahydrofuran (1:1), and heated and stirred at 100°C.

[0192] Comparative Example 2

[0193] This comparative example provides another method for preparing and degrading a biodegradable epoxy resin material, including the following steps:

[0194] Bisphenol F diglycidyl ether and isophorone diamine were mixed in equal amounts and stirred, then poured into a metal mold and cured at 50°C for 4 hours, followed by curing at 75°C for 8 hours to obtain epoxy resin cured product VII. The biodegradable epoxy resin cured product VII was broken into small pieces and soaked in an acidic degradation solution of sulfuric acid and tetrahydrofuran (1:1), and heated and stirred at 100°C.

[0195] Comparative Example 3

[0196] This comparative example provides another method for preparing a biodegradable epoxy resin material, comprising the following steps:

[0197] 0.1 mol of p-hydroxybenzaldehyde was added to a three-necked flask equipped with a reflux condenser, followed by 200 mL of methanol. The mixture was stirred until the p-hydroxybenzaldehyde was completely dissolved. Tyramine (0.1 mol) was then added to the solution. Under nitrogen protection, the reaction system was heated to 60°C and reacted for 24 hours. Stirring was stopped, the reaction system was cooled to room temperature, filtered, and dried in a vacuum oven at 60°C for 24 hours to obtain curing agent component B4 containing a Schiff base structure. Equal parts of epoxy resin component A1 and curing agent component B4 were mixed and stirred, poured into a metal mold, and cured at 50°C for 4 hours, followed by curing at 75°C for 8 hours. Curing was not achieved, therefore further degradation experiments were not conducted.

[0198] Comparative Example 4

[0199] This comparative example provides another method for preparing and degrading a biodegradable epoxy resin material, including the following steps:

[0200] Vanillinamine hydrochloride (0.1 mol) was dissolved in methanol (2.3 mol) and mixed for 10 min. Then anhydrous potassium carbonate (0.1 mol) was added, and the mixture was heated to 55 °C and stirred for 30 min to obtain a neutralization reaction solution. Vanillin (0.1 mol) was dissolved in methanol (1.2 mol), and the resulting vanillin solution was added to the neutralization reaction solution. The mixture was reacted at 55 °C for 4 h. After the reaction was completed, the reaction solution was poured into petroleum ether to precipitate the precipitate. The precipitate was filtered, and the resulting solid component was dried in a vacuum oven at 80 °C for 12 h to obtain bisphenol monomer. Bisphenol monomer (0.1 mol) was dissolved in epichlorohydrin (1.0 mol), stirred at 40 °C for 30 min, and the phase transfer catalyst tetrabutylammonium bromide (10.3 mmol) was added. The mixture was heated to 80 °C and reacted for 2 h. After cooling to room temperature, the mixture was treated in an ice bath. When the temperature dropped below 0 °C, 40% sodium hydroxide aqueous solution (0.2 mol) was added, and the system was maintained at this temperature for 5 h. The mixture was extracted with ethyl acetate, and the resulting organic phase was washed with deionized water until neutral. The ethyl acetate was completely removed by rotary evaporation to obtain epoxy resin III containing a Schiff base structure, which was directly used as epoxy resin component A4. Epoxy resin component A4 and curing agent component B1 were mixed in equal proportions and stirred. The mixture was poured into a metal mold and cured at 50 °C for 4 h, then heated to 75 °C and cured for 8 h to obtain epoxy resin cured product VII. Epoxy resin cured product VII was broken into small pieces and soaked in an acidic degradation solution of sulfuric acid and tetrahydrofuran (1:1), and heated and stirred at 100 °C.

[0201] The epoxy resin cured products prepared in the embodiments and comparative examples of this application were tested, and the results of the epoxy resin cured products are shown in Table 1.

[0202] Table 1 Comparison of physicochemical properties of epoxy resin cured products

[0203]

[0204] As shown in Table 1, the biodegradable epoxy resin materials of Examples 1-5 can all be completely degraded by heating in acidic solution and have excellent mechanical properties: glass transition temperature ≥105℃, tensile modulus ≥2840MPa, tensile strength ≥69.3MPa, flexural modulus ≥2610MPa, and flexural strength ≥94.9MPa. In some preferred embodiments, the biodegradable epoxy resin materials have higher glass transition temperatures and better mechanical properties. For example, in Examples 1-4, the glass transition temperature is ≥110℃, tensile modulus ≥2940MPa, tensile strength ≥71.8MPa, flexural modulus ≥2680MPa, and flexural strength ≥95.1MPa.

[0205] The amine used in Example 1 was 4,4'-diaminodicyclohexylmethane, and the amine used in Example 2 was isophorone diamine. Example 2 exhibited a higher glass transition temperature and mechanical properties than Example 1, demonstrating that isophorone diamine can be cured to form a stronger rigid structure and a denser cross-linked network. Compared to Example 2, Example 4 has a higher density Schiff base structure, resulting in a higher glass transition temperature and mechanical properties. This demonstrates that Schiff bases can form a π-π conjugated rigid structure with benzene rings, thereby improving the glass transition temperature and mechanical properties of the cured product. In Example 3, epoxy resin component A3 has a higher density Schiff base structure, but the optimization effect on glass transition temperature and mechanical properties in Example 3 is not as good as in Example 2. This proves that introducing excessively high-density rigid structures into epoxy resins disrupts the regular arrangement of the polymer structure in the cured product, leading to a decrease in glass transition temperature and mechanical properties. The test results of Examples 2-4 show that appropriately increasing the density of the Schiff base structure can impart better overall performance to the cured product, while excessively high Schiff base structure density has an adverse effect on the overall performance of the cured product.

[0206] Compared to the embodiments, Comparative Example 1 lacks a Schiff base structure, resulting in a significantly lower glass transition temperature and mechanical properties. Furthermore, Comparative Example 1 is non-degradable. Comparative Example 2 also lacks a Schiff base structure, yet its glass transition temperature and mechanical properties are significantly reduced, indicating that the Schiff base forms a rigid π-π conjugated structure with the benzene ring, imparting biodegradability to the material. Comparative Example 3 cannot be cured under experimental conditions because phenolic hydroxyl ring-opening epoxy resin requires heating to 180-200°C for curing, leading to higher production costs compared to the embodiments. Comparative Example 4 exhibits a lower glass transition temperature and mechanical properties, indicating that a lower Schiff base density does not contribute to improving the aforementioned properties.

[0207] The technical features of the above-described embodiments and examples can be combined in any suitable manner. For the sake of brevity, not all possible combinations of the technical features in the above-described embodiments and examples are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0208] The embodiments described above merely illustrate several implementation methods of this application and should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Furthermore, it should be understood that after reading the above teachings, those skilled in the art can make various alterations or modifications to this application, and the equivalent forms obtained also fall within the protection scope of this application. It should also be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the protection scope of the appended claims. Therefore, the protection scope of this patent application should be determined by the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A biodegradable epoxy resin composition, characterized in that, The biodegradable epoxy resin composition comprises component A and component B; component A comprises a biodegradable epoxy resin monomer containing a Schiff base structure; the biodegradable epoxy resin monomer containing a Schiff base structure comprises a compound represented by formula (I): (I); Component B includes a biodegradable curing agent containing a Schiff base structure; the biodegradable curing agent containing a Schiff base structure includes a compound represented by formula (II): (II); R 11 R 22 and R 23 Each is independently selected from C3-C20 cycloalkylene groups; R 12 R 13 and R 21 They were each independently selected from C6-C30 arylene groups.

2. The biodegradable epoxy resin composition according to claim 1, characterized in that, R 11 R 22 and R 23 Each is independently selected from C6-C18 cycloalkylene groups; R 12 R 13 and R 21 They were each independently selected from C6-C10 arylene groups.

3. The biodegradable epoxy resin composition according to claim 2, characterized in that, R 11 R 22 and R 23 Selected independently from: 、 、 、 ;R 12 R 13 and R 21 Selected independently ;R 31 R 32 R 33 R 34 and R 35 Each is independently selected from hydrogen or C1-C9 alkyl groups.

4. The biodegradable epoxy resin composition according to any one of claims 1-3, characterized in that, The method for preparing the biodegradable epoxy resin containing a Schiff base structure includes the following steps: reacting a diamine compound A with a hydroxyl compound to obtain an intermediate compound; the structure of the diamine compound A is as follows: The structure of the intermediate compound is as follows: ;R 41 R 42 and R 43 respectively with R 11 R 12 and R 13 The definitions are the same; the intermediate compound is reacted with epichlorohydrin to obtain the biodegradable epoxy resin containing the Schiff base structure; and / or, the preparation method of the biodegradable curing agent containing the Schiff base structure includes the following steps: reacting diamine compound B with an aldehyde compound to obtain the biodegradable curing agent containing the Schiff base structure; the structure of the diamine compound B is as follows: ;R 51 With R 21 The definitions are the same.

5. The biodegradable epoxy resin composition according to any one of claims 1-3, characterized in that, Component A, by weight, comprises 10-40 parts of glycidyl ether epoxy resin monomer and 60-100 parts of degradable epoxy resin monomer containing a Schiff base structure; and / or, component B, by weight, comprises 10-20 parts of diamine compound C and 80-100 parts of degradable curing agent containing a Schiff base structure; the structure of diamine compound C is as follows: ;R 61 Selected from C3-C20 cycloalkylene compounds.

6. The biodegradable epoxy resin composition according to any one of claims 1-3, characterized in that, The molar ratio of component A to component B is 2:(1-1.2).

7. The use of the biodegradable epoxy resin composition according to any one of claims 1-6 in the preparation of wind turbine blades.

8. A method for preparing biodegradable epoxy resin materials, characterized in that, The preparation method using the biodegradable epoxy resin composition according to any one of claims 1-6 includes the following steps: mixing component A and component B, pouring the resulting mixture into a mold, heating at a first temperature for a first time, and then heating at a second temperature for a second time to obtain the biodegradable resin cured product; the first temperature is 40℃-60℃, and the first time is 3h-5h; the second temperature is 70℃-80℃, and the second time is 6h-12h.

9. A biodegradable epoxy resin material, characterized in that, It is prepared by the preparation method described in claim 8.

10. The degradation method of the biodegradable epoxy resin material according to claim 9, characterized in that, The method includes the following steps: crushing the biodegradable epoxy resin material to obtain a block; immersing the block in an acidic degradation solution and stirring at a third temperature; the third temperature is 90℃-110℃; the acidic degradation solution comprises an acid and a solvent; optionally, the acid includes at least one of hydrochloric acid, sulfuric acid, nitric acid, acetic acid, trifluoroacetic acid, methanesulfonic acid, hydrobromic acid, hydrofluoric acid, lactic acid, formic acid, benzoic acid, and salicylic acid; optionally, the solvent includes at least one of water, alcohol, dichloromethane, chloroform, benzene, toluene, xylene, acetate, tetrahydrofuran, acetone, N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide, and N-methylpyrrolidone.

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