Preparation method of multi-stimulus-response degradable thermosetting resin containing ketene ester group

Abstract

The invention discloses a preparation method of multi-stimulus-response degradable thermosetting resin containing ketene ester groups, and the method comprises the following steps: carrying out thermocuring cross-linking reaction on a compound containing multifunctional acetoacetate and polyaldehyde to generate the degradable thermosetting resin. The multi-stimulus-response degradable thermosetting resin prepared by the method has excellent creep resistance and can be kept stable under long-time exposure at 120 DEG C. The multi-stimulus-response degradable thermosetting resin and the composite material prepared by using the thermosetting resin as the matrix bring a major breakthrough to the composite material industry, so that the multi-stimulus-response degradable thermosetting resin and the composite material are more suitable for application in extreme environments such as high temperature and high pressure; the application range of the material is expanded, and more innovation and development opportunities are expected to be brought to related fields.

Description

Technical Field

[0001] The invention relates to a method for preparing a degradable and recyclable thermosetting resin, in particular to a method for preparing a degradable thermosetting resin with a high glass transition temperature. Background Art

[0002] In the field of composite materials, the development of degradable resin-based composite materials is to solve the problems of environmental pollution and resource consumption faced by traditional resin-based composite materials. Traditional resin-based composite materials usually use non-degradable resins such as epoxy resin as the matrix. Although they have excellent mechanical properties and corrosion resistance, they will have a greater negative impact on the environment during the entire life cycle of production, use and disposal, such as the impact on soil, water sources, and wild animals and plants. At present, the pyrolysis of these wastes requires a large amount of fossil resources and chemical raw materials, and the large amount of waste gas generated also increases the pressure on environmental resources.

[0003] In order to solve these problems, biodegradable resin-based composite materials introduce biodegradable resin groups, such as imine bonds and acetal bonds, which can be decomposed under certain conditions, thereby reducing environmental pollution and resource consumption. However, many biodegradable materials on the market currently have a common problem, that is, their creep temperature is low. This means that these materials may creep at lower temperatures, reducing the stability and reliability of the materials. Summary of the invention

[0004] In order to solve the problem of low creep resistance of existing degradable thermosetting resins, the present invention provides a method for preparing a multi-stimulus responsive degradable thermosetting resin containing enone ester groups. The multi-stimulus responsive degradable thermosetting resin prepared by the method has excellent creep resistance and can remain stable under long-term exposure at 120°C. The multi-stimulus responsive degradable thermosetting resin of the present invention and the composite material prepared with the thermosetting resin as the matrix have brought major breakthroughs to the composite material industry, making the multi-stimulus responsive degradable thermosetting resin and the composite material more suitable for applications in extreme environments such as high temperature and high pressure, expanding the application range of the material, and is expected to bring more innovation and development opportunities to related fields.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A compound containing a multifunctional acetoacetate has the following molecular structure formula:

[0007]

[0008] In the formula, R1 is one of a hydrogen atom, an alkyl group, an alkoxy group, a cycloalkyl group, a heterocyclic group, a heterocycloalkyl group, an alkenyl group, a cycloalkenyl group, an aromatic group, a heteroaromatic group, an alkane heteroalkyl group, and an alkynyl group. R1 is preferably one of a hydrogen atom and a methyl group, and n is an integer from 0 to 100.

[0009] A method for preparing the above-mentioned compound containing multifunctional acetoacetate is prepared according to the following reaction process:

[0010]

[0011] The specific preparation steps are as follows:

[0012] The polyol and acetoacetate undergo alcoholysis or transesterification reaction in a solvent to synthesize a compound containing multifunctional acetoacetate, wherein:

[0013] The structural formula of the polyol is The structural formula of acetoacetate is The molar ratio of the two is 0.1 to 10:1;

[0014] R1 and R2 are one of hydrogen atom, alkyl, alkoxy, cycloalkyl, heterocyclic group, heterocycloalkyl, alkenyl, cycloalkenyl, aromatic group, heteroaromatic group, alkynyl; R1 and R2 may be the same or different; R1 is preferably hydrogen atom and methyl group, and R2 is preferably tert-butyl and ethyl group;

[0015] The solvent is at least one of water, isopentane, n-pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, carbon tetrachloride, benzene, toluene, methanol, ethanol, ethylene glycol, propanol, isopropanol, butanol, isobutanol, tert-butanol, amyl alcohol, benzyl alcohol, ethyl acetate, ether, petroleum ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, pyridine, acetone, acetonitrile, xylene, chlorobenzene, o-dichlorobenzene, dichloromethane, carbon tetrachloride, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide;

[0016] The reaction temperature is 120-200°C.

[0017] A method for preparing a multi-stimulus responsive degradable thermosetting resin containing enone ester groups comprises the following steps:

[0018] A compound containing a multifunctional acetoacetate is subjected to a heat curing crosslinking reaction with a polyaldehyde to generate a degradable thermosetting resin, wherein:

[0019] The weight ratio of the compound containing multifunctional acetoacetate to the polyaldehyde is 0.1 to 10:1;

[0020] The polyaldehyde comprises at least one of o-phthalaldehyde, terephthalaldehyde, isophthalaldehyde, trimesaldehyde, benzyl trimesaldehyde, benzophenone trimesaldehyde, alkane dialdehyde, alkane trialdehyde, cycloalkane dialdehyde heterocyclic polyaldehyde;

[0021] The temperature of the heat curing cross-linking reaction is 110-200°C;

[0022] The degradable thermosetting resin contains the following breakable cross-linking structure:

[0023]

[0024] In the formula, R1 is one of hydrogen atom, alkyl, alkoxy, cycloalkyl, heterocyclic group, heterocycloalkyl, alkenyl, cycloalkenyl, aromatic group, heteroaromatic group, alkane heteroalkyl, alkynyl; R3 is one of alkylene, alkylene, cycloalkylene, alkylene cycloalkylene, heterocycloalkylene, cycloalkenylene, alkylene cycloalkenylene, heterocycloalkenylene, aromatic group, alkylene aromatic group, heteroaromatic group, alkylene heteroaromatic group, secondary amine alkylene secondary amine group, oxyalkylene oxy group, oxyheteroaromatic oxy group; n is one of integers from 0 to 100;

[0025] The multi-stimulus responsive degradable thermosetting resin containing ketene ester groups can be used as a matrix to prepare a degradable resin composite material, and the composite material is prepared from a compound containing multifunctional acetoacetate, a polyaldehyde, a reinforcement, and auxiliary materials, wherein:

[0026] The polyaldehyde comprises at least one of o-phthalaldehyde, terephthalaldehyde, isophthalaldehyde, trimesaldehyde, benzyl trimesaldehyde, benzophenone trimesaldehyde, alkane dialdehyde, alkane trialdehyde, cycloalkane dialdehyde heterocyclic polyaldehyde;

[0027] The reinforcement comprises at least one of carbon fiber, glass fiber, natural fiber, chemical fiber, fabric made of fiber material, metal nanoparticles, metal oxide nanoparticles, nanocarbon material, boron nitride nanomaterial, and organic nanoparticles;

[0028] The auxiliary materials include at least one of accelerators, coupling agents, defoamers, leveling agents, ultraviolet absorbers, toughening agents, thickeners, antioxidants, brighteners, diluents, plasticizers, fluorescent agents, pigments, and fillers.

[0029] A method for degrading a degradable thermosetting resin and a degradable resin composite material, comprising the following two technical solutions:

[0030] Technical Solution 1: At room temperature or under heating conditions, acid and solvent are used as degradation liquids to achieve degradation of degradable thermosetting resins and degradable resin composites under mechanical stirring, wherein:

[0031] The mass concentration of the acid in the solvent is 0.1 to 100%;

[0032] The heating temperature is 0 to 200° C. and the heating time is 1 to 120 hours;

[0033] The acid is at least one of hydrochloric acid, nitric acid, propionic acid, citric acid, p-toluenesulfonic acid, sulfurous acid, phosphoric acid, perchloric acid, benzoic acid, sulfuric acid, acetic acid, trifluoroacetic acid, methanesulfonic acid, hydrobromic acid, hydrofluoric acid, lactic acid, formic acid, salicylic acid, and phthalic acid;

[0034] The solvent is at least one of water, isopentane, n-ethylene glycol, propanol, isopropanol, butanol, isobutanol, tert-butanol, pyridine, acetone, pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, carbon tetrachloride, benzene, toluene, amyl alcohol, benzyl alcohol, ethyl acetate, ethyl ether, petroleum ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, xylene, chlorobenzene, o-dichlorobenzene, dichloromethane, carbon tetrachloride, methanol, ethanol, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0035] Technical Solution 2: At room temperature or under heating conditions, amines and solvents are used as degradation liquids to achieve degradation of thermosetting resins and degradable resin composites under mechanical stirring, wherein:

[0036] The mass concentration of the amine in the solvent is 0.1 to 100%;

[0037] The heating temperature is 0 to 200° C. and the heating time is 1 to 120 hours;

[0038] The amine is at least one of ethylenediamine, propylenediamine, butylenediamine, hexylenediamine, isophoronediamine, meta-xylylenediamine, alkylenedicyclohexylamine, diethylenetriamine, triethylenetetramine, oleylamine, ethanolamine, diethanolamine, isopropanolamine, aniline, benzylamine, p-methylbenzylamine, and N-ethylbenzylamine;

[0039] The solvent is at least one of water, isopentane, n-ethylene glycol, propanol, isopropanol, butanol, isobutanol, tert-butanol, pyridine, acetone, pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, carbon tetrachloride, benzene, toluene, amyl alcohol, benzyl alcohol, ethyl acetate, ethyl ether, petroleum ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, xylene, chlorobenzene, o-dichlorobenzene, dichloromethane, carbon tetrachloride, methanol, ethanol, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

[0040] Compared with the prior art, the present invention has the following advantages:

[0041] 1. The present invention prepares multifunctional acetoacetate by reacting polyol with acetoacetate compounds, and introduces ketene ester into the cross-linked structure of resin by cross-linking and curing reaction with polyaldehyde. Under the conditions of acid and solvent or amine solvent, the cross-linked structure containing ketene ester group can undergo reverse reaction of condensation of ethyl acetoacetate and aldehyde, and degrade to obtain resin oligomer containing formyl group and acetoacetate group, thereby achieving the purpose of degrading thermosetting resin. The ketene ester introduced by the present invention has large bond energy and is not easy to break under external load and high temperature conditions, so the prepared resin can have excellent mechanical and heat resistance properties.

[0042] 2. The degradable thermosetting resin prepared by the present invention is used in a fiber-reinforced composite material. Under the degradation conditions provided by the present invention, the thermosetting resin in the fiber-reinforced composite material is degraded into a polymer with a smaller molecular weight. The polymer can be dissolved in an organic solvent. After a simple separation, the resin matrix and the fiber can be separated, thereby achieving the purpose of recycling and reusing the fiber reinforcement. At the same time, the present invention provides a degradation and recovery method for acids and amines of degradable thermosetting resins and composite materials. The resin degradation products and solvents can be recycled and reused, and no secondary pollution sources will be generated for the environment. It is an economically feasible industrial production route. DETAILED DESCRIPTION

[0043] The technical solution of the present invention is further described below in conjunction with the embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be included in the protection scope of the present invention.

[0044] Example 1: Preparation of Compound I

[0045] 64.6 g of tert-butyl acetoacetate and 12.4 g of ethylene glycol were dissolved in 250 mL of toluene, and after complete dissolution, they were transferred to a 500 mL round-bottom flask and heated under reflux at 130 ° C for 3 h. During this period, a Soxhlet extractor was used to continuously separate toluene and tert-butyl alcohol produced by the reaction. When no more liquid was added to the collector, vacuum was connected until no more bubbles were generated in the round-bottom flask. The product was washed 3 times with saturated brine and dried to obtain compound I, the structural formula of which is as follows:

[0046]

[0047] The yield is as high as 93%. 1 H-NMR(d-DMSO):4.51(s,4H),3.61(s,4H),2.45(s,6H).

[0048] Example 2: Preparation of Compound II

[0049] Dissolve 64.6g of tert-butyl acetoacetate and 16.3g of trimethylolpropane in 250mL of xylene, transfer to a 500mL round-bottom flask after complete dissolution, and heat under reflux at 130°C for 3h. During this period, use a Soxhlet extractor to continuously separate xylene and tert-butyl alcohol produced by the reaction. When no more liquid is added to the collector, connect to vacuum until no more bubbles are generated in the round-bottom flask. Wash the product with saturated brine 3 times and dry it to obtain compound II, the structural formula of which is as follows:

[0050]

[0051] The yield is as high as 85%. 1 H-NMR(d-DMSO):4.24(s,6H),3.71(s,6H),2.55(s,9H),1.19(s,3H).

[0052] Example 3: Compound 1 and trimesic acid form a degradable thermosetting resin 1

[0053] At room temperature, 2.3 g of trimesaldehyde and 5.0 g of compound I prepared in Example 1 were dissolved in 10 mL of DMSO, stirred evenly, and then transferred to a stainless steel mold pre-coated with a release agent, heated at 105° C. for 2 h to form a gel, and heated at 145° C. for 6 h to completely cure. After cooling to room temperature, a degradable thermosetting resin I was obtained.

[0054] Example 4: Compound II and isophthalaldehyde generate degradable thermosetting resin II

[0055] At room temperature, 2.6 g of isophthalaldehyde and 5.0 g of compound II prepared in Example 2 were dissolved in 10 mL of THF, stirred evenly, and then transferred to a stainless steel mold pre-coated with a release agent, heated at 85°C for 2 h to form a gel, and heated at 145°C for 6 h to completely cure. After cooling to room temperature, a degradable thermosetting resin II was obtained.

[0056] Example 5: Degradation and recovery of degradable thermosetting resin in acid solution

[0057] 25 mg of the degradable thermosetting resin 1 prepared in Example 3, 5 mL of 1M HCl and 15 mL of DMSO were added to a 50 mL glass bottle and stirred at 60° C. for 2 h, and the degradable resin was completely degraded to obtain a clear and transparent yellow solution. The solution was neutralized with a saturated sodium carbonate solution and the degradation product was recovered, with a recovery rate of up to 94%.

[0058] Example 6: Degradation and recovery of degradable thermosetting resin 1 in amine solution

[0059] In a 50 mL glass bottle, 25 mg of the degradable thermosetting resin I prepared in Example 3 and 20 mL of a DMSO solution containing 45% isophorone diamine were added and stirred at 60° C. for 6 h. The mixture was completely degraded to obtain a clear and transparent yellow solution.

[0060] Example 7: Degradation and recovery of degradable thermosetting resin II in acid solution

[0061] 25 mg of the degradable thermosetting resin II prepared in Example 4, 4 mL of 1M HCl and 16 mL of DMSO were added to a 50 mL glass bottle and stirred at 60° C. for 2 h, and the solution was completely degraded to obtain a clear and transparent yellow solution. The solution was neutralized with a saturated sodium carbonate solution and the degradation product was recovered, with a recovery rate of up to 90%.

[0062] Example 8: Degradation and recovery of degradable thermosetting resin II in amine solution

[0063] In a 50 mL glass bottle, 25 mg of the degradable thermosetting resin II prepared in Example 4 and 20 mL of a DMSO solution containing 30% benzylamine were added and stirred at 60° C. for 4 h. The mixture was completely degraded to obtain a clear and transparent yellow solution.

[0064] Test example 1:

[0065] 1) The viscosity and gel time of the degradable thermosetting resin I and the degradable thermosetting resin II before curing in Example 3 and Example 4 were detected. The specific results are shown in Table 1.

[0066] 2) The thermal properties and mechanical properties of the degradable thermosetting resin I and the degradable thermosetting resin II after curing in Example 3 and Example 4 were detected. The specific results are shown in Table 1.

[0067] Table 1

[0068]

[0069]

[0070] Test Example 2

[0071] The degradation performance of the degradable thermosetting resin I and the degradable thermosetting resin II in the acid solution and the amine solution in Example 3 and Example 4 was tested. The specific results are shown in Table 2.

[0072] Table 2

[0073]

[0074]

Claims

1. A compound containing a multifunctional acetoacetate, characterized in that The compound has the following molecular structure formula: In the formula, R1 is one of hydrogen atom, alkyl, alkoxy, cycloalkyl, heterocyclic group, heterocycloalkyl, alkenyl, cycloalkenyl, aromatic group, heteroaromatic group, alkane-heteroalkyl, and alkynyl, and n is one of integers from 0 to 100.

2. The compound containing a multifunctional acetoacetate according to claim 1, characterized in that The R1 is preferably one of a hydrogen atom and a methyl group.

3. A method for preparing a compound containing a multifunctional acetoacetate according to any one of claims 1 to 2, characterized in that The method comprises the following steps: The polyol and acetoacetate undergo alcoholysis or transesterification reaction in a solvent to synthesize a compound containing multifunctional acetoacetate, wherein: The structural formula of the polyol is The structural formula of acetoacetate is The molar ratio of the two is 0.1 to 10:1; R1 and R2 are one of hydrogen atom, alkyl, alkoxy, cycloalkyl, heterocyclic, heterocycloalkyl, alkenyl, cycloalkenyl, aromatic, heteroaromatic, alkanoalkyl, and alkynyl; The reaction temperature is 120-200°C.

4. The method for preparing a compound containing a multifunctional acetoacetate according to claim 3, characterized in that The R1 is preferably a hydrogen atom and a methyl group, and R2 is preferably a tert-butyl group and an ethyl group; the solvent is at least one of water, isopentane, n-pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, carbon tetrachloride, benzene, toluene, methanol, ethanol, ethylene glycol, propanol, isopropanol, butanol, isobutanol, tert-butanol, amyl alcohol, benzyl alcohol, ethyl acetate, ether, petroleum ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, pyridine, acetone, acetonitrile, xylene, chlorobenzene, o-dichlorobenzene, dichloromethane, carbon tetrachloride, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

5. A method for preparing a multi-stimulus responsive degradable thermosetting resin containing enone ester groups, characterized in that The method comprises the following steps: A compound containing the multifunctional acetoacetate according to any one of claims 1 to 2 is subjected to a heat curing crosslinking reaction with a polyaldehyde to generate a degradable thermosetting resin, wherein: The weight ratio of the compound containing multifunctional acetoacetate to the polyaldehyde is 0.1 to 10:1; The polyaldehyde comprises at least one of o-phthalaldehyde, terephthalaldehyde, isophthalaldehyde, trimesaldehyde, benzyl trimesaldehyde, benzophenone trimesaldehyde, alkane dialdehyde, alkane trialdehyde, cycloalkane dialdehyde heterocyclic polyaldehyde; The temperature of the heat curing cross-linking reaction is 110-200°C; The degradable thermosetting resin contains the following breakable cross-linking structure: In the formula, R1 is one of hydrogen atom, alkyl, alkoxy, cycloalkyl, heterocyclic group, heterocycloalkyl, alkenyl, cycloalkenyl, aromatic group, heteroaromatic group, alkane heteroalkyl, and alkynyl; R3 is one of alkylene, alkylene, cycloalkylene, alkylene cycloalkylene, heterocycloalkylene, cycloalkenylene, alkylene cycloalkenylene, heterocycloalkenylene, aromatic group, alkylene aromatic group, heteroaromatic group, alkylene heteroaromatic group, secondary amine alkylene secondary amine group, oxyalkylene oxy group, and oxyheteroaromatic oxy group; and n is one of integers from 0 to 100.

6. A method for degrading a degradable thermosetting resin prepared by the method of claim 5, characterized in that The method comprises the following steps: At room temperature or under heating conditions, acid and solvent are used as degradation liquids, and degradation of degradable thermosetting resins and degradable resin composites is achieved under mechanical stirring, wherein: The mass concentration of the acid in the solvent is 0.1 to 100%; The heating temperature is 0 to 200° C. and the heating time is 1 to 120 hours.

7. The method for degrading a degradable thermosetting resin according to claim 6, characterized in that The acid is at least one of hydrochloric acid, nitric acid, propionic acid, citric acid, p-toluenesulfonic acid, sulfurous acid, phosphoric acid, perchloric acid, benzoic acid, sulfuric acid, acetic acid, trifluoroacetic acid, methanesulfonic acid, hydrobromic acid, hydrofluoric acid, lactic acid, formic acid, salicylic acid, and phthalic acid; the solvent is at least one of water, isopentane, n-ethylene glycol, propanol, isopropanol, butanol, isobutanol, tert-butanol, pyridine, acetone, pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, carbon tetrachloride, benzene, toluene, amyl alcohol, benzyl alcohol, ethyl acetate, ether, petroleum ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, xylene, chlorobenzene, o-dichlorobenzene, dichloromethane, carbon tetrachloride, methanol, ethanol, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

8. A method for degrading a degradable thermosetting resin prepared by the method of claim 5, characterized in that The method comprises the following steps: At room temperature or under heating conditions, amines and solvents are used as degradation liquids to achieve degradation of thermosetting resins and degradable resin composites under mechanical stirring, wherein: The mass concentration of the amine in the solvent is 0.1 to 100%; The heating temperature is 0 to 200° C. and the heating time is 1 to 120 hours.

9. The method for degrading a degradable thermosetting resin according to claim 8, characterized in that The amine is at least one of ethylenediamine, propylenediamine, butylenediamine, hexylenediamine, isophoronediamine, meta-xylenediamine, alkylene dicyclohexylamine, diethylenetriamine, triethylenetetramine, oleylamine, ethanolamine, diethanolamine, isopropanolamine, aniline, benzylamine, p-methylbenzylamine, and N-ethylbenzylamine; the solvent is at least one of water, isopentane, n-ethylene glycol, propanol, isopropanol, butanol, isobutanol, tert-butanol, pyridine, acetone, pentane, petroleum ether, hexane, cyclohexane, cyclopentane, heptane, carbon tetrachloride, benzene, toluene, amyl alcohol, benzyl alcohol, ethyl acetate, ether, petroleum ether, isopropyl ether, tetrahydrofuran, chloroform, dioxane, xylene, chlorobenzene, o-dichlorobenzene, dichloromethane, carbon tetrachloride, methanol, ethanol, acetonitrile, N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide.

10. Use of the degradable thermosetting resin prepared by the method of claim 5 as a matrix in a degradable resin composite material.

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