Bio-based polyester material prepared based on aconitic acid

Abstract

The invention belongs to the technical field of polyester materials, and discloses a bio-based polyester material prepared based on aconitic acid, and the preparation process comprises the following steps: (1) carrying out cyclization reaction on aconitic acid and one or more amino acids and derivatives thereof to prepare a dicarboxylic acid monomer containing a cyclic structure; (2) carrying out polycondensation on the dicarboxylic acid monomer prepared in the step (1) and glycols with different structures to obtain a polyester material; the obtained polyester material has high glass transition temperature and thermal decomposition temperature. According to the bio-based polyester material provided by the invention, the problem that high conversion rate cannot be realized due to the existence of a crosslinking phenomenon in the process of preparing the polyester material from bio-based polybasic acid is avoided, and the obtained polyester material has relatively high molecular weight (Mn) of 3000g / mol-30000g / mo, relatively narrow molecular weight distribution # imgabs0 # 1-5, relatively high glass transition temperature (Tg) of 60-250 DEG C and thermal decomposition temperature (Td5) of 250-500 DEG C; meanwhile, the reaction raw materials are derived from bio-based, the preparation process is mild, the operation is simple and feasible, the cost is controllable, and the yield is high.

Description

Technical Field

[0001] The invention belongs to the field of polyester materials, and specifically relates to a bio-based polyester material prepared based on aconitic acid. Background Art

[0002] Commercial plastics currently on the market, such as polyethylene terephthalate (PET), polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP) and polystyrene (PS), all come from non-recyclable petroleum resources. Petroleum-based plastics occupy the main market for plastics due to their low production costs and wide application scenarios. Petroleum-based plastics produced each year account for more than 70% of the total plastic production. However, if waste plastics are not properly handled, they will have a great impact on the environment. In 2017, only 9% of the world's 438 billion kilograms of waste plastics were recycled, and about 2% entered the ecosystem. In addition, this type of plastic will not hydrolyze in the natural environment, and will eventually enter our food chain in the form of microplastics, thereby endangering human health and safety. Therefore, there is an urgent need to develop renewable polymers to eliminate people's concerns about the depletion of fossil energy and human health.

[0003] Bio-based plastics were commercially produced in the late 1980s. In 2021, bioplastic production reached 2.42 million kg, accounting for only 1% of total plastic production. The reason why bioplastics have not been vigorously developed is that their high production costs and low glass transition temperature limit their further application. For example, polylactic acid (PLA), which costs the same as PET, has a glass transition temperature (T g ) is only 55℃, while PET can reach 72℃.

[0004] In fact, polyester materials have attracted much attention because of the presence of ester groups that are easily hydrolyzed, and a large amount of bio-renewable energy can be used to synthesize polyesters. For example, US patent application US2423093A reported the use of aconitic acid to prepare ethylene glycol-isopropylene glycol-sebacic acid-aconitic acid polyester materials, which gave the materials special properties and expanded the application range of the materials. However, the flexible methylene groups in this type of bio-based monomers give the materials low T g , thus limiting the application scope of the material in life.

[0005] Therefore, developing a biodegradable, high T g Polyester materials have important research significance for the development of sustainable materials and the utilization of biological resources. Summary of the invention

[0006] One of the purposes of the present invention is to provide a bio-based polyester material prepared based on aconitic acid, the molecular structure of the polyester material is as follows:

[0007]

[0008] Wherein, 0≤n≤10, m≥20, m and n are both integers; and R is independently selected from an alkyl group containing 1 to 4 carbon atoms.

[0009] Optionally, the glass transition temperature (T g ) ranges from 60-250℃, thermal decomposition temperature (T d5 ) range is 250-500°C, the molecular weight range is 3000-30000g / mol, and the molecular weight distribution is 1-5.

[0010] The second object of the present application is to provide a method for preparing a bio-based polyester material based on aconitic acid, comprising a cyclization step and an esterification step;

[0011] The cyclization reaction steps are as follows:

[0012] (1) According to the equivalent ratio, 1 equivalent of aconitic acid and 1-5 equivalents of amino acid are mixed and stirred;

[0013] (2) After adding the above raw materials, the reaction temperature is raised to 150-200° C., and the mixture is stirred during the heating process until aconitic acid and the corresponding amino acid are completely melted;

[0014] (3) After the reaction temperature rises to 150-200°C, melt stirring is performed for 5-8 hours;

[0015] (4) After the reaction, vacuum was applied at 150°C and 0.05 mbar for 5 h to remove all the water generated by the reaction;

[0016] (5) Cooling to room temperature to obtain a cyclic dicarboxylic acid product.

[0017] Preferably, in the cyclization reaction of the present invention, the equivalent ratio of aconitic acid to amino acid is 1:(1-5), the reaction temperature is 150-200° C., and the reaction time is 5-8 h.

[0018] The cyclization process is an important step in preparing the synthetic precursor of aconitic acid bio-based polyester materials. The degree of cyclization and purity of the polymer precursor cyclic dicarboxylic acid product directly affect the molecular weight and glass transition temperature and other properties of the polyester material in the subsequent polymerization process. The inventors found that when the equivalent of aconitic acid to amino acid is 1: (1-5), the problem of the amount of reaction raw materials added not meeting the reaction raw material ratio due to insufficient raw material purity can be effectively avoided. At the same time, the cyclization reaction is carried out at 150-200°C. Within this temperature range, the cyclization reaction efficiency of aconitic acid and amino acids can be effectively improved to ensure the full progress of the cyclization reaction. The reaction temperature, reaction time, feed equivalent and other conditions involved in the cyclization reaction are all selected to ensure the stable development of the next step of esterification. Random adjustment is likely to lead to poor subsequent esterification reaction or reduced purity and performance of the final product.

[0019] The polymerization steps are as follows:

[0020] (1) mixing a cyclic dicarboxylic acid, a diol and a catalyst, wherein the molar ratio of acid to alcohol is 1:(1.5-3), and the amount of the catalyst is 1-10 mol%;

[0021] (2) prepolymerization is carried out at a reaction temperature of 180-250° C. for 5-20 hours;

[0022] (3) carrying out polycondensation at a reaction temperature of 250-300° C. for 10-30 hours;

[0023] (4) After the reaction is completed, the mixture is cooled to room temperature to obtain the final product.

[0024] Preferably, in the polymerization reaction of the present invention, the equivalent ratio of the cyclic dicarboxylic acid to the diol is 1:(1.5-3), and the amount of the catalyst used is 1-10 mol% of the amount of the dicarboxylic acid used.

[0025] Preferably, in the prepolymerization reaction of the present invention, the reaction temperature is 180-250° C. and the reaction time is 5-20 h.

[0026] Preferably, in the polycondensation reaction described in the present invention, the reaction temperature is 250-300° C. and the reaction time is 10-30 h.

[0027] The polymerization process mainly utilizes cyclic dicarboxylic acid and diol for dehydration condensation to obtain polyester products. Effective control of the degree of polymerization can design the molecular weight of the final polyester product. Because the molecular weight of the obtained polyester product is relatively high, it is necessary to ensure that the equivalent ratio of cyclic dicarboxylic acid to diol is 1: (1.5-3), and the reaction needs to be carried out at a higher reaction temperature and a longer reaction time, so as to ensure that the carboxyl groups on the cyclic dicarboxylic acid are esterified as much as possible, so that the degree of polymerization is also higher, and the molecular weight of the final polyester obtained is in the range of 3000-30000 g / mol. When the reaction conditions are not in this range, although a certain polyester product can still be obtained, the molecular weight and purity of the product will not be guaranteed, and the molecular structure of the polyester product will also change, resulting in the glass transition temperature, thermal decomposition temperature, etc. of the final polyester product will also be affected. Therefore, in order to obtain a polyester product with a larger molecular weight, the polymerization reaction needs to be carried out at a specific catalytic ratio, a higher temperature and a longer reaction time.

[0028] Optionally, the amino acids include one or more of aminoformic acid, glycine, β-alanine, γ-aminobutyric acid, 5-aminopentanoic acid, 6-aminohexanoic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

[0029] Preferably, the amino acids include one or more of carbamic acid, 6-aminocaproic acid, and 12-aminododecanoic acid.

[0030] The main reactants in the cyclization reaction are aconitic acid and amino acids, both of which are extracted from biological fermentation or biomass and are green and environmentally friendly bio-based raw materials. The cyclic dicarboxylic acid obtained by the cyclization reaction is the polymerization main body of the polyester product in the polymerization step. Compared with aconitic acid, the cyclic dicarboxylic acid contains more esterification reaction sites, which is more conducive to obtaining a high molecular weight polyester product.

[0031] Optionally, the diol is one or more of ethylene glycol, propylene glycol, butylene glycol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, 1,2-cyclopentanediol, and isosorbide.

[0032] Preferably, the diol is one or more of ethylene glycol, hexylene glycol, and isosorbide.

[0033] This type of diol can be obtained through biological fermentation and is a green and environmentally friendly bio-based raw material. At the same time, increasing the amount of diol added can effectively improve the esterification efficiency and promote the production of high molecular weight polyester products.

[0034] Optionally, the catalyst is one or more of zinc acetate, antimony trioxide, p-toluenesulfonic acid, concentrated sulfuric acid, stannous octoate, disodium hydrogen phosphate, potassium carbonate, and tetrabutyl titanate.

[0035] Preferably, the catalyst is one or more of zinc acetate, p-toluenesulfonic acid, and potassium carbonate.

[0036] All raw materials of the aconitic acid-based polyester product except the catalyst are derived from biomass, and the biocarbon content of the finally prepared plasticizer product is 100%.

[0037] Biocarbon content is gradually guiding the direction of material development. For example, the Decree No. 2016-379 issued by France requires that the biocarbon content of disposable plastic bags must be at least 30% from January 1, 2017, and the test standard is ISO 16620-2. The minimum biocarbon content required for these plastic bags will increase to 40% in 2018, 50% in 2020, and 60% in 2025. The biocarbon content in the product includes the sum of the matrix and the additive biocarbon. The aconitic acid-based polyester in this application has 100% biocarbon, which meets the relevant policy requirements and reduces the pressure on the biocarbon content of the main material.

[0038] The third purpose of the present application is to provide an application of a bio-based polyester material prepared based on aconitic acid. The bio-based polyester material prepared based on aconitic acid has adjustable rigidity and flexibility and can be used as a special engineering plastic in aerospace and other fields.

[0039] The beneficial effects of this application include but are not limited to:

[0040] 1. The bio-based polyester based on aconitic acid of the present application improves the disadvantage that the tricarboxylic acid reaction system cannot achieve a high conversion rate due to the cross-linking problem. The obtained polymer has a higher molecular weight and molecular weight distribution, and the material has a higher T g and T d5 .

[0041] 2. The raw materials of the aconitic acid-based bio-based polyester of the present application are all from biomass, obtained through synthetic biology technology, and are inherently non-toxic and environmentally friendly, with a biocarbon content of 100%.

[0042] 3. The bio-based polyester based on aconitic acid of the present application has a mild preparation process, simple and easy operation, controllable cost and high yield. DETAILED DESCRIPTION

[0043] The present application is described in detail below with reference to embodiments, but the present application is not limited to these embodiments.

[0044] The raw materials in the examples of this application are all prepared by synthetic biology technology.

[0045] Embodiment 1:

[0046] Cyclization process:

[0047] Aconitic acid and carbamic acid were mixed in an equivalent ratio of 1:1, and then the reaction temperature was raised to 150°C and stirred for 5 hours. After the reaction was completed, vacuum was applied at 150°C and a vacuum degree of 0.05 mbar for 5 hours to remove all the water generated by the reaction. The mixture was cooled to room temperature to obtain a cyclic dicarboxylic acid monomer product with a yield of 95%.

[0048] Polymerization process:

[0049] The obtained cyclic dicarboxylic acid monomer and ethylene glycol are mixed in an equivalent ratio of 1:1.5, and then 1 mol% of zinc acetate catalyst is added; then the reaction temperature is raised to 180°C for prepolymerization, and after reacting for 5 hours, the reaction temperature is raised to 250°C for condensation polymerization, and the reaction is reacted for 10 hours to finally obtain the product polyester.

[0050] Experimental results: The conversion rate of cyclic dicarboxylic acid was 97%, the molecular weight of the obtained polyester was 3000 g / mol, the molecular weight distribution was 1, and the T g At 60°C, T d5 is 250℃.

[0051] Embodiment 2:

[0052] Cyclization process:

[0053] Aconitic acid and 6-aminocaproic acid were mixed in an equivalent ratio of 1:3, and then the reaction temperature was raised to 170°C and stirred for 6 hours. After the reaction was completed, vacuum was applied at 150°C and a vacuum degree of 0.05 mbar for 5 hours to remove all the water generated by the reaction. The mixture was cooled to room temperature to obtain a cyclic dicarboxylic acid monomer product with a yield of 96%.

[0054] Polymerization process:

[0055] The obtained cyclic dicarboxylic acid monomer is mixed with hexanediol in an equivalent ratio of 1:2, and then 5 mol% of p-toluenesulfonic acid catalyst is added; then the reaction temperature is raised to 220°C for prepolymerization, and after the reaction time is 10 hours, the reaction temperature is raised to 270°C for condensation polymerization, and the reaction time is 20 hours to finally obtain the product polyester.

[0056] Experimental results: The conversion rate of cyclic dicarboxylic acid was 97%, the molecular weight of the obtained polyester was 10000 g / mol, the molecular weight distribution was 3.2, and the T g 170℃, T d5 is 370℃.

[0057] Embodiment 3:

[0058] Cyclization process:

[0059] Aconitic acid and 12-aminododecanoic acid were mixed in an equivalent ratio of 1:5, and then the reaction temperature was raised to 200°C and stirred for 8 hours. After the reaction was completed, vacuum was applied at 150°C and a vacuum degree of 0.05 mbar for 5 hours to remove all the water generated by the reaction. The mixture was cooled to room temperature to obtain a cyclic dicarboxylic acid monomer product with a yield of 94%.

[0060] Polymerization process:

[0061] The obtained cyclic dicarboxylic acid monomer and isosorbide are mixed in an equivalent ratio of 1:3, and then 10 mol% of potassium carbonate catalyst is added; then the reaction temperature is raised to 250°C for prepolymerization, and after reacting for 20 hours, the reaction temperature is raised to 300°C for condensation polymerization, and the reaction is reacted for 30 hours to finally obtain the product polyester.

[0062] Experimental results: The conversion rate of cyclic dicarboxylic acid was 95%, the molecular weight of the obtained polyester was 30000 g / mol, the molecular weight distribution was 5, and the T g At 250℃, T d5 is 500℃.

[0063] Comparative Example 1:

[0064] Cyclization process:

[0065] Aconitic acid and carbamic acid were mixed in an equivalent ratio of 1:0.5, and then the reaction temperature was raised to 100°C and stirred for 1 hour. After the reaction was completed, vacuum was drawn at 150°C and a vacuum degree of 0.05 mbar for 5 hours to remove all the water generated by the reaction. The mixture was cooled to room temperature to obtain a cyclic dicarboxylic acid monomer product with a yield of 50%.

[0066] Polymerization process:

[0067] The obtained cyclic dicarboxylic acid monomer and ethylene glycol are mixed in an equivalent ratio of 1:1, and then 0.1 mol% of zinc acetate catalyst is added; then the reaction temperature is raised to 150°C for prepolymerization, and after reacting for 5 hours, the reaction temperature is raised to 200°C for condensation polymerization, and the reaction is reacted for 10 hours to finally obtain the product polyester.

[0068] Experimental results: The conversion rate of cyclic dicarboxylic acid was 97%, the molecular weight of the obtained polyester was 3000 g / mol, the molecular weight distribution was 1, and the T g At 60°C, T d5 is 250℃.

[0069] Comparative Example 2:

[0070] Cyclization process:

[0071] Aconitic acid and carbamic acid were mixed in a 1:1 equivalent ratio, and then the reaction temperature was raised to 100°C and stirred for 1 hour. After the reaction was completed, vacuum was applied at 150°C and a vacuum degree of 0.05 mbar for 5 hours to remove all the water generated by the reaction. The mixture was cooled to room temperature to obtain a cyclic dicarboxylic acid monomer product with a yield of 97%.

[0072] Polymerization process:

[0073] The obtained cyclic dicarboxylic acid monomer and ethylene glycol are mixed in an equivalent ratio of 1:0.5, and then 0.1 mol% of zinc acetate catalyst is added; then the reaction temperature is raised to 150°C for prepolymerization, and after reacting for 5 hours, the reaction temperature is raised to 200°C for condensation polymerization, and the reaction is reacted for 10 hours to finally obtain the product polyester.

[0074] Experimental results: The conversion rate of cyclic dicarboxylic acid was 32%, the molecular weight of the obtained polyester was 700 g / mol, the molecular weight distribution was 1, and the T g At 40°C, T d5 is 230℃.

[0075] Comparative Example 3:

[0076] Cyclization process:

[0077] Aconitic acid and carbamic acid were mixed in a 1:1 equivalent ratio, and then the reaction temperature was raised to 100°C and stirred for 1 hour. After the reaction was completed, vacuum was applied at 150°C and a vacuum degree of 0.05 mbar for 5 hours to remove all the water generated by the reaction. The mixture was cooled to room temperature to obtain a cyclic dicarboxylic acid monomer product with a yield of 98%.

[0078] Polymerization process:

[0079] The obtained cyclic dicarboxylic acid monomer and ethylene glycol are mixed in an equivalent ratio of 1:1, and then 0.05 mol% of zinc acetate catalyst is added; then the reaction temperature is raised to 150°C for prepolymerization, and after reacting for 5 hours, the reaction temperature is raised to 200°C for condensation polymerization, and the reaction is reacted for 10 hours to finally obtain the product polyester.

[0080] Experimental results: The conversion rate of cyclic dicarboxylic acid was 47%, the molecular weight of the obtained polyester was 1200 g / mol, the molecular weight distribution was 3.2, and the T g At 30°C, T d5 is 150℃.

[0081] Comparative Example 4:

[0082] Cyclization process:

[0083] Aconitic acid and carbamic acid were mixed in a 1:1 equivalent ratio, and then the reaction temperature was raised to 100°C and stirred for 1 hour. After the reaction was completed, vacuum was drawn at 150°C and a vacuum degree of 0.05 mbar for 5 hours to remove all the water generated by the reaction. The mixture was cooled to room temperature to obtain a cyclic dicarboxylic acid monomer product with a yield of 95%.

[0084] Polymerization process:

[0085] The obtained cyclic dicarboxylic acid monomer and ethylene glycol are mixed in an equivalent ratio of 1:1, and then 0.1 mol% of zinc acetate catalyst is added; then the reaction temperature is raised to 100°C for prepolymerization, and after reacting for 5 hours, the reaction temperature is raised to 200°C for condensation polymerization, and the reaction is reacted for 10 hours to finally obtain the product polyester.

[0086] Experimental results: The conversion rate of cyclic dicarboxylic acid was 52%, the molecular weight of the obtained polyester was 1700 g / mol, the molecular weight distribution was 6.3, and the T g At 45°C, T d5 It is 132℃.

[0087] Comparative Example 5:

[0088] Cyclization process:

[0089] Aconitic acid and carbamic acid were mixed in a 1:1 equivalent ratio, and then the reaction temperature was raised to 100°C and stirred for 1 hour. After the reaction was completed, vacuum was applied at 150°C and a vacuum degree of 0.05 mbar for 5 hours to remove all the water generated by the reaction. The mixture was cooled to room temperature to obtain a cyclic dicarboxylic acid monomer product with a yield of 94%.

[0090] Polymerization process:

[0091] The obtained cyclic dicarboxylic acid monomer and ethylene glycol are mixed in an equivalent ratio of 1:1, and then 0.1 mol% of zinc acetate catalyst is added; then the reaction temperature is raised to 150°C for prepolymerization, and after reacting for 2 hours, the reaction temperature is raised to 200°C for condensation polymerization, and the reaction is reacted for 10 hours to finally obtain the product polyester.

[0092] Experimental results: The conversion rate of cyclic dicarboxylic acid was 18%, the molecular weight of the obtained polyester was 1450 g / mol, the molecular weight distribution was 5.2, and the T g 53℃, T d5 It is 123℃.

[0093] Comparative Example 6:

[0094] Cyclization process:

[0095] Aconitic acid and carbamic acid were mixed in a 1:1 equivalent ratio, and then the reaction temperature was raised to 100°C and stirred for 1 hour. After the reaction was completed, vacuum was applied at 150°C and a vacuum degree of 0.05 mbar for 5 hours to remove all the water generated by the reaction. The mixture was cooled to room temperature to obtain a cyclic dicarboxylic acid monomer product with a yield of 97%.

[0096] Polymerization process:

[0097] The obtained cyclic dicarboxylic acid monomer and ethylene glycol are mixed in an equivalent ratio of 1:1, and then 0.1 mol% of zinc acetate catalyst is added; then the reaction temperature is raised to 150°C for prepolymerization, and after the reaction time is 5 hours, the reaction temperature is raised to 100°C for condensation polymerization, and the reaction time is 10 hours to finally obtain the product polyester.

[0098] Experimental results: The conversion rate of cyclic dicarboxylic acid was 85%, the molecular weight of the obtained polyester was 2400 g / mol, the molecular weight distribution was 7.1, and the T g is 44℃, T d5 is 115℃.

[0099] Comparative Example 7:

[0100] Cyclization process:

[0101] Aconitic acid and carbamic acid were mixed in a 1:1 equivalent ratio, and then the reaction temperature was raised to 100°C and stirred for 1 hour. After the reaction was completed, vacuum was applied at 150°C and a vacuum degree of 0.05 mbar for 5 hours to remove all the water generated by the reaction. The mixture was cooled to room temperature to obtain a cyclic dicarboxylic acid monomer product with a yield of 97%.

[0102] Polymerization process:

[0103] The obtained cyclic dicarboxylic acid monomer and ethylene glycol are mixed in an equivalent ratio of 1:1, and then 0.1 mol% of zinc acetate catalyst is added; then the reaction temperature is raised to 150°C for prepolymerization, and after the reaction for 5 hours, the reaction temperature is raised to 200°C for condensation polymerization, and the reaction is carried out for 3 hours to finally obtain the product polyester.

[0104] Experimental results: The conversion rate of cyclic dicarboxylic acid was 78%, the molecular weight of the obtained polyester was 2100 g / mol, the molecular weight distribution was 8.2, and the T g At 34°C, T d5 is 185℃.

[0105] Experimental and test performance results

[0106] The above test data of the polyester material are recorded in Table 1 below.

[0107] Table 1

[0108]

[0109]

[0110] According to the test results in Table 1, the molecular weight of the aconitic acid-based polyester product can be regulated by regulating the ratio of aconitic acid to amino acid, the acid-alcohol ratio, the amount of catalyst added, the reaction temperature and time, and finally the molecular weight of the polyester product can be controlled between 3000-30000 g / mol. Within this molecular weight range, the polyester product has a high glass transition temperature range of 60-250°C and a high thermal decomposition temperature of 250-500°C. However, when the reaction conditions are not within the specified range, according to the comparative experimental results, the polyester product will have problems such as reduced molecular weight and low cyclic dicarboxylic acid conversion rate. The reduced molecular weight and cyclic dicarboxylic acid conversion rate will cause the structure of the polyester product to change, and the final result is that the glass transition temperature and thermal decomposition temperature are greatly reduced. The change in product properties will also have a certain impact on the application of subsequent products.

Claims

1. A bio-based polyester material prepared based on aconitic acid, characterized in that: The molecular structure of polyester material is as follows: Wherein, 0≤n≤10, m≥20, m and n are both integers; and R is independently selected from an alkyl group containing 1 to 4 carbon atoms.

2. A bio-based polyester material prepared based on aconitic acid as claimed in claim 1, characterized in that: The glass transition temperature of polyester materials ranges from 60-250°C.

3. A bio-based polyester material prepared based on aconitic acid as claimed in claim 1, characterized in that: The thermal decomposition temperature of polyester materials ranges from 250-500°C.

4. A bio-based polyester material prepared based on aconitic acid as claimed in claim 1, characterized in that: The molecular weight range of the polyester material is 3000-30000 g / mol, and the molecular weight distribution is 1-5.

5. A method for preparing a bio-based polyester material based on aconitic acid according to any one of claims 1 to 4, characterized in that: It includes a cyclization step and a polymerization step; The cyclization reaction steps are as follows: (1) According to the equivalent ratio, 1 equivalent of aconitic acid and 1-5 equivalents of amino acid are mixed and stirred; (2) After adding the above raw materials, the reaction temperature is raised to 150-200° C., and the mixture is stirred during the heating process until aconitic acid and the corresponding amino acid are completely melted; (3) After the reaction temperature rises to 150-200°C, melt stirring is performed for 5-8 hours; (4) After the reaction, vacuum was applied at 150°C and 0.05 mbar for 5 h to remove all the water generated by the reaction; (5) cooling to room temperature to obtain a cyclic dicarboxylic acid product; The polymerization steps are as follows: (1) mixing a cyclic dicarboxylic acid, a diol and a catalyst, wherein the molar ratio of the cyclic dicarboxylic acid to the diol is 1:(1.5-3), and the amount of the catalyst is 1-10 mol%; (2) prepolymerization is carried out at a reaction temperature of 180-250° C. for 5-20 hours; (3) carrying out polycondensation at a reaction temperature of 250-300° C. for 10-30 hours; (4) After the reaction is completed, the mixture is cooled to room temperature to obtain the final product.

6. A method for preparing a bio-based polyester material based on aconitic acid as claimed in claim 5, characterized in that: The amino acids include one or more of aminoformic acid, glycine, β-alanine, γ-aminobutyric acid, 5-aminopentanoic acid, 6-aminocaproic acid, 7-aminoheptanoic acid, 8-aminooctanoic acid, 9-aminononanoic acid, 10-aminodecanoic acid, 11-aminoundecanoic acid, and 12-aminododecanoic acid.

7. A method for preparing a bio-based polyester material based on aconitic acid as claimed in claim 5, characterized in that: The diol is one or more of ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, 1,2-cyclopentanediol and isosorbide.

8. A method for preparing a bio-based polyester material based on aconitic acid as claimed in claim 5, characterized in that: The catalyst is one or more of zinc acetate, antimony trioxide, p-toluenesulfonic acid, concentrated sulfuric acid, stannous octoate, disodium hydrogen phosphate, potassium carbonate, and tetrabutyl titanate.

9. A method for preparing a bio-based polyester material based on aconitic acid according to any one of claims 5 to 8, characterized in that: All raw materials except the catalyst come from biomass, and the final polyester product has a biocarbon content of 100%.

10. An application of a bio-based polyester material prepared based on aconitic acid as claimed in any one of claims 1 to 4, characterized in that: Used in aerospace field.

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