Shape memory polyether ester copolymer with micro-crosslinking structure and preparation method thereof

Abstract

The invention discloses a shape memory polyether ester copolymer with a micro-crosslinking structure and a preparation method of the shape memory polyether ester copolymer. Firstly, an epoxy compound containing double bonds and a cyclic lactone compound are used as comonomers, and a small amount of ester groups are introduced into a polyether structure to serve as ester exchange sites, so that the compatibility of polyester and polyether structural units is improved, and the polyether ester copolymer with uniform and controllable performance is prepared; then, an isocyanate compound is introduced to synthesize the polyether ester copolymer with a straight-chain structure, and the polyether ester copolymer contains a carbamate group, so that physical crosslinking points among molecular chains can be formed; and further introducing a cross-linking agent to react with an unsaturated bond in a molecular chain to obtain the polyether ester copolymer with a micro-cross-linked structure. The method is simple in preparation route, low in cost and environmentally friendly, the obtained polymer has the shape memory characteristic, the shape recovery rate of the material is obviously improved compared with that of polyether ester of a straight chain structure, and the performance of the polymer can be regulated and controlled by adjusting copolymerization components and the crosslinking degree.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of high polymer materials, and particularly relates to a shape memory polyether ester copolymer with a micro-crosslinking structure and a preparation method thereof. BACKGROUND

[0002] Polyester materials are widely used in various fields such as films, fibers and bottle pieces due to their excellent performance, but polyester materials with single structure are limited by their own properties and cannot meet diversified needs. Therefore, efficient modification of polyester has important theoretical research significance and practical application value. Combining ether functional groups with ester segments to obtain polyether-polyester copolymers is an effective modification method to improve the performance of polyester. Polyether ester copolymers have excellent mechanical properties and heat resistance, and are widely used in the fields of automobiles, medical devices, communication equipment and aerospace. There are mainly three methods for preparing polyether ester copolymers at present: (1) physical blending method: polyether polyols and polyester polyols are physically blended in a certain proportion, but due to the poor compatibility of polyether and polyester, the product prepared by this method has the problem of uneven performance. Moreover, the polyurethane material prepared by using such polyether ester polyols often has poor performance (patent CN116265506A); (2) condensation polymerization method: polyether ester copolymers are prepared by condensation polymerization of diacid, diol and polyether polyol (patent CN106832307A). The advantage of this method is that the polyether ester component is controllable, and the uniformity of the product is better than that of the polyether ester copolymer prepared by the physical blending method, but the activity of the hydroxyl group at the end of the polyether polyol is low, and the reaction temperature is high, which can easily cause the diacid to undergo decarboxylation, oxidation and other side reactions, affecting the quality of the product; (3) ring-opening polymerization method: polyether ester copolymers are prepared by ring-opening polymerization of an epoxide compound and a cyclic lactone under the action of a catalyst. The advantage of this method is that the reaction conditions are relatively mild and the material structure is controllable, but it often needs to develop new catalysts, which is high in cost and not suitable for industrial production. Moreover, due to the large difference in ring strain between the alkylene oxide and the cyclic lactone, the reactivity ratio difference is large, so it is often difficult to prepare polyether-polyester random copolymers (Chemical Reviews, 1959, 59(4): 737-799), and the product obtained often has poor uniformity. In addition, the synthesized polyether ester copolymers often lack functional sites, which limits the post-modification of the polymer molecular chain and the fine design of the structure.

[0003] 3,4-epoxy-1-butene (EPB) is a new fine chemical intermediate synthesized by epoxidation of 1,3-butadiene, which has broad market potential. Since the compound has an oxygen ring and a double bond, it is a rare intermediate containing two important functional groups, but the application of EPB is mainly concentrated in the field of drug intermediates, and there is a lack of related reports on its application in the field of functional polymers. SUMMARY

[0004] To address the shortcomings of existing technologies, this invention provides a shape memory polyether ester copolymer with a micro-crosslinked structure and its preparation method.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a shape memory polyether ester copolymer with a micro-crosslinked structure includes the following steps: (1) An epoxy compound, a cyclic lactone compound, an acid anhydride compound, catalyst 1, catalyst 2, and an initiator are added to a reactor for a single reaction; the epoxy compound is 3,4-epoxy-1-butene; the cyclic lactone compound is any one of glycolide, L-lactide, D-lactide, racemic lactide, valproic acid lactone, or caprolactone; the acid anhydride compound is any one of succinic anhydride, methylsuccinic anhydride, or glutaric anhydride; catalyst 1 is a zinc-cobalt bimetallic cyanide complex; catalyst 2 is an organic carboxylate or oxide containing any one of titanium, tin, antimony, or germanium; the initiator is any one of ethylene glycol, 1,3-propanediol, 1,4-butanediol, polyethylene glycol 200, polyethylene glycol 400, polypropylene glycol 200, or polypropylene glycol 400. (2) After the pressure in the reactor drops to 0, the temperature is raised to carry out a secondary reaction to obtain polyether ester diol; (3) After cooling down, the isocyanate compound is dissolved in an organic solvent and added dropwise to the reactor for three reactions to obtain a linear polyether ester copolymer. (4) After dissolving the crosslinking agent and thermal initiator in an organic solvent, add them to the solution obtained in step (3) to carry out four reactions to obtain a shape memory polyether ester material with a micro-crosslinked structure.

[0006] Furthermore, the temperature of the single reaction in step (1) is 60~120 ℃ and the time is 0.5~3 h.

[0007] Further, in step (1), the molar ratio of the epoxy compound to the cyclic lactone compound is 1:0.1~9; the mass ratio of the catalyst 1 to the epoxy compound is 1:100~10000; the mass ratio of the catalyst 2 to the cyclic lactone compound is 1:100~1000; the molar ratio of the acid anhydride compound to the epoxy compound is 1:10~100; and the molar ratio of the initiator to the epoxy compound is 1:1~200.

[0008] Furthermore, the temperature of the secondary reaction in step (2) is 100~180 ℃ and the time is 2~6 h.

[0009] Furthermore, the temperature of the three reactions in step (3) is 50~100 ℃ and the time is 3~12 h.

[0010] Further, the isocyanate compound used in step (3) is selected from any one of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate or dicyclohexylmethane-4,4'-diisocyanate, and the molar ratio of the isocyanate compound to the initiator is 1:0.9~1.2.

[0011] Further, the crosslinking agent used in step (4) is 1,6-hexanedithiol; the thermal initiator used is either benzoyl peroxide or azobisisobutyronitrile; the molar ratio of the crosslinking agent to the epoxy compound is 1:5~200, and the molar ratio of the thermal initiator to the crosslinking agent is 1:0.5~2.

[0012] Furthermore, the organic solvent mentioned in steps (3) and (4) is any one of dichloromethane, trichloromethane, and tetrahydrofuran.

[0013] Furthermore, the temperature of the four reactions in step (4) is 50~100 ℃ and the time is 3~24 h.

[0014] This invention first utilizes the epoxy compound 3,4-epoxy-1-butene and cyclic lactone as comonomers to prepare a polyether ester random copolymer with uniform and controllable properties. Then, isocyanate compounds are introduced into the reaction system for chain extension to synthesize a polyether ester copolymer containing urethane groups. Finally, a crosslinking agent is added to synthesize a micro-crosslinked polyether ester copolymer. The synthesized polymer exhibits shape memory properties, and its material properties can be controlled by adjusting the comonomer composition and the degree of crosslinking. The molar content of the polyether ester can be controlled within the range of 5–95 mol%; the shape memory transition temperature can be controlled within the range of -60–50 °C; and the shape recovery rate is >90%.

[0015] The beneficial effects of this invention are as follows: (1) The polyether ester copolymer with shape memory properties obtained in this invention is prepared from epoxy compound 3,4-epoxy-1-butene and cyclic lactone as raw materials. By adjusting the feed ratio, its glass transition temperature or melting point can be controlled, ranging from -60 to 50 °C.

[0016] (2) Compared with linear polyether ester copolymers, the micro-crosslinked polyether ester copolymers obtained in this invention have higher molecular weight and better shape memory properties, higher shape memory recovery rate, and the material properties can be controlled by adjusting the copolymer components and crosslinking degree. The shape memory transition temperature control range is -60~50 ℃, and the shape recovery rate is above 90%.

[0017] (3) The method for preparing polyether ester copolymers with shape memory properties of the present invention is simple, low-cost, green and environmentally friendly, and has the prospect and potential for large-scale production. Attached Figure Description

[0018] Figure 1 The sample prepared in Example 1 1 H NMR spectrum.

[0019] Figure 2 The image shows the DSC spectrum of the sample prepared in Example 1.

[0020] Figure 3 The sample prepared in Example 2 1 H NMR spectrum.

[0021] Figure 4 The image shows the DSC spectrum of the sample prepared in Example 2.

[0022] Figure 5 The sample prepared in Example 3 1 H NMR spectrum.

[0023] Figure 6 The image shows the DSC spectrum of the sample prepared in Example 3.

[0024] Figure 7 The sample prepared for Comparative Example 1 1 H NMR spectrum.

[0025] Figure 8 The image shows the DSC spectrum of the sample prepared in Comparative Example 1.

[0026] Figure 9 The sample prepared for Comparative Example 2 1 H NMR spectrum.

[0027] Figure 10 The image shows the DSC spectrum of the sample prepared in Comparative Example 2.

[0028] Figure 11 The sample prepared for Comparative Example 3 1 H NMR spectrum.

[0029] Figure 12 The image shows the DSC spectrum of the sample prepared in Comparative Example 3. Detailed Implementation

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0031] Example 1 A 250 mL autoclave equipped with a mechanical stirrer was dried at 120 °C for more than 12 h, evacuated, and allowed to cool to room temperature before being purged with nitrogen. Under nitrogen protection, 3,4-epoxy-1-butene (3.5 g, 0.05 mol), L-lactide (28.8 g, 0.2 mol), and succinic anhydride (0.5 g, 5 mmol) were weighed at room temperature and added to the autoclave. A zinc-cobalt bimetallic cyanide complex (Zn-Co DMCC, 7 mg, commercial catalyst) with a mass ratio of 1:500 to 3,4-epoxy-1-butene, stannous octoate (28.8 mg) with a mass ratio of 1:1000 to L-lactide, and polypropylene glycol 200 (0.646 g, 3.23 mmol) were also added. The autoclave was sealed, and the reaction temperature was set to 80 °C for 2 hours. After the pressure inside the reactor dropped to zero, the temperature was raised to 130 °C, and the reaction continued for 6 hours to obtain a polyether ester diol. Then, after the temperature dropped to 60 °C, 20 mL of tetrahydrofuran was added to the reactor. Once the polyether ester diol was completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (0.54 g / 20 mL) was added dropwise to the reactor, and the reaction was maintained at this temperature for 3 hours to obtain a linear polyether ester copolymer. Next, a solution of 1,6-hexanedithiol / azobisisobutyronitrile (AIBN) / tetrahydrofuran (0.38 g / 0.41 g / 20 mL) was added dropwise to the reactor, and the mixture was stirred vigorously. The polymer solution was poured into a polytetrafluoroethylene mold and reacted at 60 °C for 6 hours to evaporate the solvent and obtain a polymer film. The polymer film was placed in a vacuum drying oven and dried under vacuum at 40 °C for 12 hours to obtain a micro-crosslinked polyether ester material.

[0032] The results of the proton nuclear magnetic resonance spectrum show that ( Figure 1 The polyether content in the polyether ester diol is 13.4%, and thermal performance tests show that ( Figure 2 The glass transition temperature of the resulting micro-crosslinked polyether ester material was 22.2 ℃; the gel content of the material was 12.8% (gel content refers to the portion of the polymer that is insoluble in organic solvents, tested according to GB / T 37498-2019 standard); and the shape recovery rate of the material was 93.2%.

[0033] Example 2 A 250 mL autoclave equipped with a mechanical stirrer was dried at 120 °C for more than 12 h, evacuated, and allowed to cool to room temperature before being purged with nitrogen. Under nitrogen protection, 3,4-epoxy-1-butene (3.5 g, 0.05 mol), L-lactide (28.8 g, 0.2 mol), and succinic anhydride (0.5 g, 5 mmol) were weighed at room temperature and added to the autoclave. A zinc-cobalt bimetallic cyanide complex (Zn-Co DMCC, 7 mg) with a mass ratio of 1:500 to 3,4-epoxy-1-butene, stannous octoate (28.8 mg) with a mass ratio of 1:1000 to L-lactide, and polypropylene glycol 200 (0.646 g, 3.23 mmol) were also added. The autoclave was sealed, and the reaction temperature was set to 80 °C for 2 hours. After the pressure inside the reactor dropped to zero, the temperature was raised to 130 °C, and the reaction continued for 6 hours to obtain a polyether ester diol. Then, after the temperature dropped to 60 °C, 20 mL of tetrahydrofuran was added to the reactor. Once the polyether ester diol was completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (0.54 g / 20 mL) was added dropwise to the reactor, and the reaction was maintained at this temperature for 3 hours to obtain a linear polyether ester copolymer. Next, a solution of 1,6-hexanedithiol / AIBN / tetrahydrofuran (0.19 g / 0.205 g / 20 mL) was added dropwise to the reactor, with vigorous stirring. The polymer solution was poured into a polytetrafluoroethylene mold and reacted at 60 °C for 6 hours to evaporate the solvent and obtain a polymer film. The polymer film was placed in a vacuum drying oven and dried under vacuum at 40 °C for 12 hours to obtain a micro-crosslinked polyether ester material.

[0034] The results of the proton nuclear magnetic resonance spectrum show that ( Figure 3 The polyether content in the polyether ester diol is 12.8%, and thermal performance tests show that ( Figure 4 The glass transition temperature of the resulting micro-crosslinked polyether ester material was 35.9 ℃; the gel content of the material was 11.5%, and the shape recovery rate of the material was 91.7%.

[0035] Example 3 A 250 mL autoclave equipped with a mechanical stirrer was dried at 120 °C for more than 12 h, evacuated, and allowed to cool to room temperature before being filled with nitrogen for use. Under nitrogen protection, 3,4-epoxy-1-butene (3.5 g, 0.05 mol), ε-caprolactone (22.8 g, 0.2 mol), and succinic anhydride (0.5 g, 5 mmol) were weighed at room temperature and added to the autoclave. A zinc-cobalt bimetallic cyanide complex (Zn-Co DMCC, 7 mg) with a mass ratio of 1:500 to 3,4-epoxy-1-butene, stannous octoate (22.8 mg) with a mass ratio of 1:1000 to ε-caprolactone, and polypropylene glycol 200 (0.526 g, 2.63 mmol) were also added. The autoclave was sealed, and the reaction temperature was set to 80 °C for 2 hours. After the pressure inside the reactor dropped to zero, the temperature was raised to 130 °C, and the reaction continued for 6 hours to obtain a polyether ester diol. Then, after the temperature dropped to 60 °C, 20 mL of tetrahydrofuran was added to the reactor. Once the polyether ester diol was completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (0.54 g / 20 mL) was added dropwise to the reactor, and the reaction was maintained at this temperature for 3 hours to obtain a linear polyether ester copolymer. Next, a solution of 1,6-hexanedithiol / AIBN / tetrahydrofuran (0.38 g / 0.41 g / 20 mL) was added dropwise to the reactor, and the mixture was stirred vigorously. The polymer solution was poured into a polytetrafluoroethylene mold and reacted at 60 °C for 6 hours to evaporate the solvent, yielding a polymer film. The polymer film was placed in a vacuum drying oven and dried under vacuum at 40 °C for 12 hours to obtain a micro-crosslinked polyether ester material.

[0036] The results of the proton nuclear magnetic resonance spectrum show that ( Figure 5 The polyether content in the polyether ester diol is 20.0%, and thermal performance tests show that ( Figure 6 The resulting micro-crosslinked polyether ester material had a melting point of 55.2 °C, a gel content of 17.1%, and a shape recovery rate of 90.4%.

[0037] Comparative Example 1 A 250 mL autoclave equipped with a mechanical stirrer was dried at 120 °C for more than 12 h, evacuated, and allowed to cool to room temperature before being purged with nitrogen. Under nitrogen protection, 3,4-epoxy-1-butene (3.5 g, 0.05 mol), L-lactide (28.8 g, 0.2 mol), and succinic anhydride (0.5 g, 5 mmol) were weighed at room temperature and added to the autoclave. A zinc-cobalt bimetallic cyanide complex (Zn-Co DMCC, 7 mg) with a mass ratio of 1:500 to 3,4-epoxy-1-butene, stannous octoate (28.8 mg) with a mass ratio of 1:1000 to L-lactide, and polypropylene glycol 200 (0.646 g, 3.23 mmol) were also added. The autoclave was sealed, and the reaction temperature was set to 80 °C for 2 hours. After the pressure inside the reactor dropped to zero, the temperature was raised to 130 °C, and the reaction continued for 6 hours to obtain a polyether ester diol. Then, after the temperature dropped to 60 °C, 20 mL of tetrahydrofuran was added to the reactor. Once the polyether ester diol was completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (0.54 g / 20 mL) was added dropwise to the reactor, and the reaction was maintained at this temperature for 3 hours to obtain a linear polyether ester copolymer. The polymer solution was poured into a polytetrafluoroethylene mold, and the solvent was evaporated to obtain a polymer film. The polymer film was placed in a vacuum drying oven and dried under vacuum at 40 °C for 12 hours to obtain a linear polyether ester material.

[0038] The 1H NMR spectrum results showed that the molar content of polyether in the polyether ester diol was 12.8%, and the thermal performance test showed that the glass transition temperature of the obtained polyether ester copolymer was 32.7℃; the shape recovery rate of the material was 75.5%.

[0039] Comparative Example 2 A 250 mL autoclave equipped with a mechanical stirrer was dried at 120 °C for more than 12 h, evacuated, and allowed to cool to room temperature before being filled with nitrogen for use. Under nitrogen protection, 3,4-epoxy-1-butene (3.5 g, 0.05 mol), ε-caprolactone (22.8 g, 0.2 mol), and succinic anhydride (0.5 g, 5 mmol) were weighed at room temperature and added to the autoclave. A zinc-cobalt bimetallic cyanide complex (Zn-Co DMCC, 7 mg) with a mass ratio of 1:500 to 3,4-epoxy-1-butene, stannous octoate (22.8 mg) with a mass ratio of 1:1000 to ε-caprolactone, and polypropylene glycol 200 (0.646 g, 3.23 mmol) were also added. The autoclave was sealed, and the reaction temperature was set to 80 °C for 2 hours. After the pressure inside the reactor dropped to zero, the temperature was raised to 130 °C, and the reaction continued for 6 hours to obtain a polyether ester diol. Then, after the temperature dropped to 60 °C, 20 mL of tetrahydrofuran was added to the reactor. Once the polyether ester diol was completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (0.54 g / 20 mL) was added dropwise to the reactor, and the reaction was maintained at this temperature for 3 hours to obtain a linear polyether ester copolymer. The polymer solution was poured into a polytetrafluoroethylene mold, and the solvent was evaporated to obtain a polymer film. The polymer film was placed in a vacuum drying oven and dried under vacuum at 40 °C for 12 hours to obtain a linear polyether ester material.

[0040] The 1H NMR spectrum results showed that the molar content of polyether in the polyether ester diol was 20.0%, and the thermal performance test showed that the melting point of the obtained polyether ester copolymer was 55.5℃; the shape recovery rate of the material was 80.4%.

[0041] Comparative Example 3 A 250 mL autoclave equipped with a mechanical stirrer was dried at 120 °C for more than 12 h, evacuated, and cooled to room temperature before being purged with nitrogen. Under nitrogen protection, propylene oxide (2.9 g, 0.05 mol), ε-caprolactone (22.8 g, 0.2 mol), and succinic anhydride (0.5 g, 5 mmol) were weighed at room temperature and added to the autoclave. A zinc-cobalt bimetallic cyanide complex (Zn-Co DMCC, 7 mg) with a mass ratio of 1:500 to propylene oxide, stannous octoate (22.8 mg) with a mass ratio of 1:1000 to ε-caprolactone, and polypropylene glycol 200 (0.646 g, 3.23 mmol) were also added. The autoclave was sealed, and the reaction temperature was set to 80 °C for 2 hours. After the pressure inside the autoclave dropped to zero, the temperature was raised to 130 °C, and the reaction continued for 6 hours to obtain a polyether ester diol. After the temperature drops to 60℃, 20 mL of tetrahydrofuran is added to the reactor. Once the polyether ester diol is completely dissolved, a tetrahydrofuran solution of hexamethylene diisocyanate (0.54 g / 20 mL) is added dropwise to the reactor. The reaction is maintained at this temperature for 3 hours to obtain a linear polyether ester copolymer. The polymer solution is poured into a polytetrafluoroethylene mold, and the solvent is evaporated to obtain a polymer film. The polymer film is placed in a vacuum drying oven and dried under vacuum at 40℃ for 12 hours to obtain a linear polyether ester material.

[0042] The 1H NMR spectrum results showed that the molar content of polyether in the polyether ester diol was 25.2%, and the thermal performance test showed that the melting point of the obtained polyether ester copolymer was 53.0℃; the shape recovery rate of the material was 70.5%.

[0043] The above description is only a preferred embodiment of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should be included in the scope of the present invention.

Claims

1. A method for preparing a shape memory polyether ester copolymer with a micro-crosslinked structure, characterized in that: Includes the following steps: (1) An epoxy compound, a cyclic lactone compound, an acid anhydride compound, catalyst 1, catalyst 2, and an initiator are added to a reactor for a single reaction; the epoxy compound is 3,4-epoxy-1-butene; the cyclic lactone compound is any one of glycolide, L-lactide, D-lactide, racemic lactide, valproic acid lactone, or caprolactone; the acid anhydride compound is any one of succinic anhydride, methylsuccinic anhydride, or glutaric anhydride; catalyst 1 is a zinc-cobalt bimetallic cyanide complex; catalyst 2 is an organic carboxylate or oxide containing any one of titanium, tin, antimony, or germanium; the initiator is any one of ethylene glycol, 1,3-propanediol, 1,4-butanediol, polyethylene glycol 200, polyethylene glycol 400, polypropylene glycol 200, or polypropylene glycol 400. (2) After the pressure in the reactor drops to 0, the temperature is raised to carry out a secondary reaction to obtain polyether ester diol; (3) After cooling down, the isocyanate compound is dissolved in an organic solvent and added dropwise to the reactor for three reactions to obtain a linear polyether ester copolymer. (4) After dissolving the crosslinking agent and thermal initiator in an organic solvent, add them to the solution obtained in step (3) to carry out four reactions to obtain a shape memory polyether ester material with a micro-crosslinked structure.

2. The preparation method according to claim 1, characterized in that: The temperature of the first reaction in step (1) is 60~120 ℃ and the time is 0.5~3 h.

3. The preparation method according to claim 1, characterized in that: In step (1), the molar ratio of the epoxy compound to the cyclic lactone compound is 1:0.1~9; the mass ratio of the catalyst 1 to the epoxy compound is 1:100~10000; the mass ratio of the catalyst 2 to the cyclic lactone compound is 1:100~1000; the molar ratio of the acid anhydride compound to the epoxy compound is 1:10~100; and the molar ratio of the initiator to the epoxy compound is 1:1~200.

4. The preparation method according to claim 1, characterized in that: The temperature of the secondary reaction in step (2) is 100~180 ℃ and the time is 2~6 h.

5. The preparation method according to claim 1, characterized in that: The temperature of the three reactions in step (3) is 50~100 ℃ and the time is 3~12 h. The temperature after cooling is 50~100 ℃.

6. The preparation method according to claim 1, characterized in that: The isocyanate compound used in step (3) is selected from any one of isophorone diisocyanate, hexamethylene diisocyanate, diphenylmethane diisocyanate or dicyclohexylmethane-4,4'-diisocyanate, and the molar ratio of isocyanate compound to initiator is 1:0.9~1.

2.

7. The preparation method according to claim 1, characterized in that: The crosslinking agent used in step (4) is 1,6-hexanedithiol; the thermal initiator used is either benzoyl peroxide or azobisisobutyronitrile; the molar ratio of crosslinking agent to epoxy compound is 1:5~200, and the molar ratio of thermal initiator to crosslinking agent is 1:0.5~2.

8. The preparation method according to claim 1, characterized in that: The organic solvent mentioned in steps (3) and (4) is any one of dichloromethane, trichloromethane, and tetrahydrofuran.

9. The preparation method according to claim 1, characterized in that: The temperature of the four reactions in step (4) is 50~100 ℃ and the time is 3~24 h.

10. A shape memory polyether ester copolymer with a micro-crosslinked structure prepared by any one of claims 1 to 9, characterized in that: The molar content of polyether ester in the shape memory polyether ester copolymer with micro-crosslinked structure is controlled within the range of 5~95mol; the shape memory transition temperature is controlled within the range of -60~50 ℃, and the shape recovery rate is >90%.

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