Crystalline polyesteramide as well as preparation method and application thereof

Abstract

The invention discloses crystalline polyesteramide as well as a preparation method and application thereof, and relates to the technical field of high polymer materials. The method comprises the following steps: taking aziridine with a protecting group and cyclic anhydride as polymeric monomers, carrying out bulk polymerization, melt polymerization or solution polymerization under the action of a catalyst to obtain amorphous polyesteramide, and carrying out polymer post-treatment and aziridine protecting group removal to obtain the crystalline polyesteramide with a-C = O-NH-structure. The method has the advantages that the adopted monomers are rich in source, cheap and easy to obtain, the polymer is rich in structure and diversified in structure, and the polymerization method is simple. The prepared polyesteramide has excellent crystallinity and degradability, and has potential application prospects in the fields of biology, medicine, flexible electronics and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer materials, and particularly relates to a crystalline polyester amide, a preparation method thereof, and an application thereof. Background Art

[0002] Polyester amide is a type of polymer material containing both amide bonds and ester bonds in the main chain. It simultaneously has the excellent mechanical properties of polyamide and the biocompatibility and degradability of polyester. It is one of the polymers with excellent comprehensive properties and shows broad application prospects in the fields of medicine, hydrogels, elastomers, and intelligent materials. Currently, the preparation methods of polyester amide mainly include condensation polymerization and ring-opening copolymerization. The two types of monomers used in the condensation polymerization method are diols and diesters or diacid compounds containing amide groups in the molecule. The condensation polymerization process follows a step-growth mechanism and the reaction is reversible. Its main disadvantages are uncontrollable reaction, high product dispersion coefficient, low polymer molecular weight, and often accompanied by side reactions. In recent years, the alternating copolymerization reaction of aziridine and cyclic anhydride has become a new strategy for preparing polyester amide. In 1985, Angne and colleagues at the University of Concepción, Chile, first reported the spontaneous oligomerization reaction of aziridine and maleic anhydride, but only obtained a poorly soluble polymer with a structure similar to polyester amide, and its structure and properties could not be clearly characterized and determined. In 2020, Professor Ren Weimin at Dalian University of Technology used 7-methylhexamethylene bicyclic guanidine (MTBD) as a catalyst and benzyl alcohol as an initiator to first achieve the complete alternating copolymerization reaction of 2-methyl-N-benzyl aziridine and phthalic anhydride, and prepared a new type of polyester amide with controllable sequence. It was found that this copolymerization reaction is a living polymerization. Thanks to the rich variety and strong modification of monomers, the author prepared a variety of new polyester amides with clear structures, but there are still problems such as low polymerization reaction activity, low polymer molecular weight, and cyclic polymers.

[0003] Although the synthetic method of preparing polyester amide by alternating copolymerization of aziridine / cyclic anhydride has made great progress and development, there are still some problems. For example, the prepared polyester amide usually contains a small amount of polyamine component, and the content of polyester amide units is less than 99%, resulting in a decline in material properties; the synthesized polymer is usually in an amorphous state and its thermal properties are relatively poor. Summary of the Invention

[0004] Aiming at the deficiencies in the above background art, the present invention mainly solves the problems of low content of alternating copolymerized polyester amide units, poor crystallinity of the polymer, and poor thermal properties in the prior art. The present invention provides a crystalline polyester amide, a preparation method thereof, and an application thereof.

[0005] The first object of the present invention is to provide a preparation method of a crystalline polyester amide, comprising the following steps:

[0006] Using a protected aziridine and a cyclic anhydride as polymerization monomers, under the action of a catalyst, through bulk polymerization, melt polymerization or solution polymerization, an amorphous polyester amide is obtained, and then through polymer post-treatment, the aziridine protecting group is removed to obtain a crystalline polyester amide with a -C=O-NH- structure;

[0007] Among them, the catalyst is an organic catalyst or a metal organic catalyst;

[0008] The synthetic route of the crystalline polyester amide is as follows:

[0009]

[0010] Among them, R 1 and R 2 are each independently selected from H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3 or OCH2CH3;

[0011] R is selected from one of the following:

[0012]

[0013] Among them, R 6 is selected from H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

[0014] Preferably, the organic catalyst is one or more of the following:

[0015]

[0016] Among them, X is one of Cl, Br, NO3, OAc.

[0017] Preferably, the metal organic catalyst is:

[0018]

[0019] In the formula, M is Al 3+ 、Fe 3+ 、Co 3+ 、Ni 3+ 、Cr 3+ 、Mn 3+ or Ru 3+ ;

[0020] X is F - 、Cl - 、Br - 、I - 、NO3 - 、CH3COO - 、CCl3COO- , CF3COO - , ClO4 - , BF4 - , BPh4 - , N3 - , p - toluate, p - toluenesulfonate, o - nitrophenolate, p - nitrophenolate, m - nitrophenolate, 2,4 - dinitrophenolate, 3,5 - dinitrophenolate, 2,4,6 - trinitrophenolate, 3,5 - dichlorophenolate, 3,5 - difluorophenolate, 3,5 - bis(trifluoromethyl)phenolate or pentafluorophenolate anion;

[0021] R 3 is

[0022] R 4 H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2;

[0023] R 5 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

[0024] Preferably, the protected aziridine compound is selected from one or more of the following:

[0025]

[0026] R 1 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3 or OCH2CH3;

[0027] R 2 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3 or OCH2CH3;

[0028] R 6 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

[0029] Preferably, the cyclic anhydride is selected from one or more of the following:

[0030]

[0031] The molar ratio of the protected aziridine to the cyclic anhydride is 1:10 to 10:1;

[0032] The molar ratio of the protected aziridine to the catalyst is 10:1 to 10000:1;

[0033] The temperature of the polymerization reaction is -20 to 200 °C, and the reaction time is 0.1 to 96 h.

[0034] Preferably, the process for removing the aziridine protecting group is as follows:

[0035]

[0036] Removal conditions: Pd / C, where the molar ratio of the number of polymer repeating units to the Pd catalyst content is 1:100 to 10000:1; hydrogen pressure 0.5 to 10 MPa, removal temperature: 0 - 100 °C; the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours;

[0037] Alternatively, the process for removing the aziridine protecting group is as follows:

[0038]

[0039] Removal conditions: the molar ratio of the acetic acid solution of HBr (33%) to the polymer repeating units is 1 to 1000; removal reaction temperature: -20 to 100 °C; the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours.

[0040] Preferably, the process for removing the aziridine protecting group is as follows:

[0041]

[0042] Removal conditions: the molar ratio of the acetic acid solution of HBr (33%) to the polymer repeating units is 1 to 1000; removal reaction temperature: -20 to 100 °C; the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours.

[0043] Preferably, the process for removing the aziridine protecting group is as follows:

[0044]

[0045] Removal conditions: Sodium bis(2-methoxyethoxy)aluminate (Red-Al) is used as a catalyst, and the molar ratio of Red-Al to the repeating unit of the polymer is 1 / 100 to 100 / 1. The reaction temperature is 0 to 100 °C. The solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, and ethylene glycol dimethyl ether; the removal time is 1 to 99 hours.

[0046] The second object of the present invention is to provide a crystalline poly(ester amide).

[0047] The third object of the present invention is to provide an application of a crystalline poly(ester amide) in medicine, hydrogels, elastomers, or smart materials.

[0048] Compared with the prior art, the beneficial effects of the present invention are:

[0049] The present invention provides a crystalline poly(ester amide), a preparation method, and an application thereof. In the present invention, a traditional polymerization method adopts a polycondensation polymerization process, which follows a step-growth mechanism and the reaction is reversible, resulting in uncontrollable reactions, a high dispersity coefficient of the product, a low molecular weight of the polymer, and often accompanied by side reactions. In contrast, the present invention adopts an anionic ring-opening polymerization mechanism, and the polymerization process follows a living polymerization process. Therefore, this method mainly solves the problems of low content of alternating copoly(ester amide) units, poor crystallinity of the polymer, and poor thermal properties in the prior art. By introducing a protecting group through an aziridine monomer, after efficient polymerization and purification, a crude poly(ester amide) is obtained, and through a simple post-treatment process, a crystalline poly(ester amide) material can be prepared. The melting temperature of the polymer is between 100 and 200 °C, and the polymer has excellent thermal properties.

[0050] The monomers involved in the present invention are rich in sources, cheap and easy to obtain, the polymer has a rich structure and diverse structures, and the polymerization method is simple. The prepared poly(ester amide) has excellent crystallinity and degradability, and has potential application prospects in the fields of biology, medicine, and flexible electronics. Description of the Drawings

[0051] Figure 1 1H NMR spectrum of the amorphous poly(ester amide) obtained by degradation in Example 1.

[0052] Figure 2 13C NMR spectrum of the amorphous poly(ester amide) obtained by degradation in Example 1.

[0053] Figure 3 1H NMR spectrum of the crystalline cyclic anhydride obtained by degradation in Example 1.

[0054] Figure 4 The polymer after removing the protecting group as proved by 1H NMR, FT-IR, DSC, and XRD tests in Example 1.

[0055] Figure 5 1H NMR spectrum of the amorphous poly(ester amide) obtained by degradation in Example 2.

[0056] Figure 6 13C NMR spectrum of the amorphous poly(ester amide) obtained by degradation in Example 2.

[0057] Figure 7 1H NMR spectrum of the crystalline cyclic anhydride obtained by degradation in Example 2.

[0058] Figure 8 Polymer after deprotecting as proved by DSC and XRD tests in Example 2. Detailed implementation manners

[0059] In order to enable those skilled in the art to better understand and implement the technical solutions of the present invention, the present invention will be further described below with reference to specific examples and drawings. However, the examples given are not intended to limit the present invention.

[0060] The object of the present invention is to provide a preparation method of a crystalline poly(ester amide), mainly solving the problems of low content of alternating copoly(ester amide) units, poor crystallinity of the polymer, and poor thermal properties in the prior art.

[0061] To achieve the above object, the first aspect of the present invention provides a preparation method of a crystalline poly(ester amide), comprising the following steps:

[0062] Using protected aziridine and cyclic anhydride as polymerization monomers, under the action of a catalyst, through bulk polymerization, melt polymerization or solution polymerization, an amorphous poly(ester amide) is obtained, and then through polymer post-treatment, the aziridine protecting group is removed to obtain a crystalline poly(ester amide) having a -C=O-NH- structure;

[0063] Among them, the catalyst is an organic catalyst or a metal-organic catalyst;

[0064] The synthesis route of the crystalline poly(ester amide) is as follows:

[0065]

[0066] Among them, R 1 and R 2 are each independently selected from H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3 or OCH2CH3;

[0067] R is selected from one of the following:

[0068]

[0069] Among them, R 6Selected from H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

[0070] The bulk polymerization, melt polymerization or solution polymerization adopted in the present invention has a polymerization reaction temperature of -20 to 200 °C and a reaction time of 0.1 to 96 h.

[0071] Exemplarily, a method for preparing a crystalline polyester amide includes using an organic / metal organic compound as a catalyst, placing a protected aziridine, a cyclic anhydride and the catalyst in a reaction vessel, reacting at -20 - 200 °C for 0.1 - 96 h, purifying and drying to obtain an amorphous polyester amide, and then through a simple post-treatment to remove the aziridine protecting group to obtain a crystalline polyester amide with a -C=O-NH- structure.

[0072] The organic catalyst is one or more of the following:

[0073]

[0074] Among them, X is one of Cl, Br, NO3, OAc.

[0075] The metal organic catalyst is:

[0076]

[0077] In the formula, M is Al 3+ 、Fe 3+ 、Co 3+ 、Ni 3+ 、Cr 3+ 、Mn 3+ or Ru 3+ ;

[0078] X is F - 、Cl - 、Br - 、I - 、NO3 - 、CH3COO - 、CCl3COO - 、CF3COO - 、ClO4 - 、BF4 - 、BPh4 - 、N3 -, p-toluic acid root, p-toluenesulfonic acid root, o-nitrophenol oxygen, p-nitrophenol oxygen, m-nitrophenol oxygen, 2,4-dinitrophenol oxygen, 3,5-dinitrophenol oxygen, 2,4,6-trinitrophenol oxygen, 3,5-dichlorophenol oxygen, 3,5-difluorophenol oxygen, 3,5-bis(trifluoromethyl)phenol oxygen or pentafluorophenol oxygen anion;

[0079] R 3 is

[0080] R 4 H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2;

[0081] R 5 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

[0082] The protected aziridine compound is selected from one or more of the following:

[0083]

[0084] R 1 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3 or OCH2CH3;

[0085] R 2 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3 or OCH2CH3;

[0086] R 6 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

[0087] The cyclic anhydride is selected from one or more of the following:

[0088]

[0089] The molar ratio of the protected aziridine to the cyclic anhydride is 1:10 to 10:1;

[0090] The molar ratio of the protected aziridine to the catalyst is 10:1 to 10000:1;

[0091] The temperature of the polymerization reaction is -20 to 200 °C, and the reaction time is 0.1 to 96 h.

[0092] The process for removing the aziridine protecting group is as follows:

[0093]

[0094] Removal conditions: Pd / C, where the molar ratio of the polymer repeat unit to the Pd catalyst content is 1:100 - 10000:1; hydrogen pressure 0.5 - 10 MPa, removal temperature: 0 - 100 °C; the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours;

[0095] Alternatively, the process for removing the aziridine protecting group is as follows:

[0096]

[0097] Removal conditions: the molar ratio of the acetic acid solution of HBr (33%) to the polymer repeat unit is 1 - 1000; removal reaction temperature: -20 - 100 °C; the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours.

[0098] The process for removing the aziridine protecting group is as follows:

[0099]

[0100] Removal conditions: the molar ratio of the acetic acid solution of HBr (33%) to the polymer repeat unit is 1 - 1000; removal reaction temperature: -20 - 100 °C; the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours.

[0101] The process for removing the aziridine protecting group is as follows:

[0102]

[0103] Removal conditions: Red-Al (sodium bis(2-methoxyethoxy)aluminum dihydride) is used as the catalyst, the molar ratio of Red-Al to the polymer repeat unit is 1 / 100 - 100 / 1, reaction temperature: 0 - 100 °C, the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours.

[0104] The second aspect of the present invention provides a crystalline polyesters amide. The number average molecular weight of the polyesters amide is 100 to 100,000 g / mol, and the molecular weight distribution is 1.1 to 2.4.

[0105] The third aspect of the present invention provides an application of the crystalline polyesters amide in medicine, hydrogel, elastomer or intelligent material.

[0106] It should be noted that the experimental methods used in the present invention are all conventional methods unless otherwise specified; the reagents and materials used, unless otherwise specified, can be purchased on the market.

[0107] In the present invention, the serial numbers of the materials used are as shown in the following figure:

[0108]

[0109] Example 1

[0110] In a 10 mL reaction flask, the following were added in sequence at a set temperature: a certain amount of catalyst PPNOAc (0.01 mmol), aziridine Az Cbz (1.00 mmol), cyclic anhydride PA (1.00 mmol) and solvent dichloromethane (2 mL). The reaction flask was maintained at 25 °C and after 48 h, stirring was stopped. The polymerization product was precipitated and washed three times with dichloromethane / methanol and dried to a constant weight under vacuum to obtain an amorphous polyesters amide.

[0111] The molecular weight and its distribution of the polymer were determined by gel permeation chromatography; its 1 1H NMR was measured with a Bruker-400 MHz to calculate the content of ester amide units in the polymerization product. Its 13 13C NMR was measured with a 500 MHz NMR. Then, 200 mg of the polymer was placed in a 100 mL high-pressure reactor, 20 mg of Pd / C catalyst was added to a dichloromethane / methanol mixed solvent, 2 MPa of H2 was introduced, the temperature was set at 40 °C, and after reacting for 48 h, the Pd / C catalyst was filtered out, the filtrate was rotary evaporated and dried to obtain a crystalline polyesters amide.

[0112] Figure 1 The 1H NMR spectrum of the amorphous polyesters amide obtained by degradation in Example 1. The peaks at 4.20 - 4.6 ppm are the peaks of the methylene hydrogens in the main chain of the polyesters amide, the peak at 4.80 ppm is the peak of the methylene on the CBZ of N in the polyesters amide, and the peaks at 6.80 - 7.90 ppm are the hydrogens on the aromatic ring of the polymer.

[0113] Figure 2 The 13C NMR spectrum of the amorphous polyesters amide obtained by degradation in Example 1. Figure 31H NMR spectrum of the crystalline cyclic anhydride obtained by degradation in Example 1. The hydrogens of the methylene groups in the polymer backbone are at 3.50 and 4.25 ppm. Since the CBZ group is completely removed, the characteristic peak at 4.80 ppm disappears. Figure 4 , which was proved by 1H NMR, FT-IR, DSC and XRD tests that the polymer after removing the protecting group has better crystallinity and thermal properties at 187 °C.

[0114] Example 2

[0115] Same as Example 1, except that in a 10 mL reaction flask, the following were added in sequence at the set temperature: a certain amount of catalyst PPNOAc, aziridine Az Cbz , cyclic anhydride 4,5-DMPA and solvent dichloromethane. After keeping the reaction flask at an appropriate temperature and for the specified reaction time, the stirring was stopped. The polymerization product was precipitated and washed three times with dichloromethane / methanol and dried to a constant weight under vacuum to obtain an amorphous polyester amide. The molecular weight and its distribution of the polymer were determined by gel permeation chromatography; its 1 1H NMR was measured with a Bruker-400 MHz, and the ester amide unit content of the polymerization product was calculated. Its 13 13C NMR was measured with a 500 MHz NMR. Then the polymer was placed in a 100 mL high-pressure reactor, an appropriate amount of Pd / C catalyst was added to the mixed solvent of dichloromethane / methanol, 2 MPa H2 was introduced, and after reacting for an appropriate time, the Pd / C catalyst was filtered out, the filtrate was rotary evaporated and dried to obtain a crystalline polyester amide.

[0116] Figure 5 1H NMR spectrum of the amorphous polyester amide obtained by degradation in Example 2. The peaks of the methylene hydrogens in the polyester amide backbone are at 4.10 - 4.60 ppm, and the peak at 4.90 ppm is the peak of the Cbz methylene on the N of the polyester amide; Figure 6 13C NMR spectrum of the amorphous polyester amide obtained by degradation in Example 2. Figure 7 1H NMR spectrum of the crystalline cyclic anhydride obtained by degradation in Example 2. It can be clearly observed that the peak at 4.90 ppm, which is the peak of the Cbz methylene on the N of the polyester amide, disappears, proving that the protecting group is completely removed. Figure 8 It was confirmed that the polymer after removing the Cbz protecting group has better crystallinity at 165 °C.

[0117] In summary, the present invention provides a method for preparing a crystalline poly(ester amide). The method includes using an organic / metal organic compound as a catalyst, placing a protected aziridine, a cyclic anhydride, and the catalyst in a reaction vessel, reacting at -20 - 200 °C for 0.1 - 96 hours, purifying and drying to obtain an amorphous poly(ester amide), and then through a simple post-treatment to remove the aziridine protecting group to obtain a crystalline poly(ester amide) having a -C=O-NH- structure. Compared with the existing methods, the monomers involved in the present invention are rich in sources, inexpensive and easily available, the polymer structures are rich and diverse, and the polymerization method is simple. The prepared poly(ester amide) has excellent crystallinity and degradability, and has potential application prospects in the fields of biology, medicine, and flexible electronics.

[0118] The above embodiments are merely examples given for clear illustration and not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

[0119] Although the embodiments of the present invention have been shown and described, for those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a crystalline polyesteramide, characterized in that, It includes the following steps: Using a protected aziridine and a cyclic anhydride as polymerization monomers, under the action of a catalyst, through bulk polymerization, melt polymerization or solution polymerization, an amorphous polyester amide is obtained, and then through polymer post-treatment, the aziridine protecting group is removed to obtain a crystalline polyester amide with a -C=O-NH- structure; Among them, the catalyst is an organic catalyst or an organometallic catalyst; The synthesis route of the crystalline polyester amide is as follows: Wherein, R 1 and R 2 are each independently selected from H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3 or OCH2CH3; R is selected from one of the following: wherein, R 6 is selected from H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

2. The method for preparing the crystalline polyestersamide according to claim 1, wherein The organic catalyst is one or more of the following: Among them, X is one of Cl, Br, NO3, OAc.

3. The method for preparing a crystalline polyestersamide according to claim 1, wherein The organometallic catalyst is: where M is Al 3+ , Fe 3+ , Co 3+ , Ni 3+ , Cr 3+ , Mn 3+ or Ru 3+ ; X is F - , Cl - , Br - , I - , NO3 - , CH3COO - , CCl3COO - , CF3COO - , ClO4 - , BF4 - , BPh4 - , N3 - , p-toluate, p-toluenesulfonate, o-nitrophenolate, p-nitrophenolate, m-nitrophenolate, 2,4-dinitrophenolate, 3,5-dinitrophenolate, 2,4,6-trinitrophenolate, 3,5-dichlorophenolate, 3,5-difluorophenolate, 3,5-bis(trifluoromethyl)phenolate or pentafluorophenolate anion; R 3 For R 4 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2; R 5 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

4. The method for preparing a crystalline polyestersamide according to claim 1, characterized in that, The protected aziridine compound is selected from one or more of the following: R 1 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3 or OCH2CH3; R 2 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3 or OCH2CH3; R 6 is H, CH3, CH2CH3, CH(CH3)2, C(CH3)3, OCH3, OCH2CH3, F, Cl, Br, I or NO2.

5. The method for preparing the crystalline polyestersamide according to claim 1, characterized in that, The cyclic anhydride is selected from one or more of the following: The molar ratio of the protected aziridine to the cyclic anhydride is 1:10 to 10:1; The molar ratio of the protected aziridine to the catalyst is 10:1 to 10000:1; The temperature of the polymerization reaction is -20 to 200 °C, and the reaction time is 0.1 to 96 h.

6. The method for preparing a crystalline poly(ester amide) according to claim 1, wherein The process of removing the aziridine protecting group is as follows: Removal conditions: Pd / C, where the molar ratio of the number of polymer repeating units to the molar content of the Pd catalyst is 1:100 to 10000:1; hydrogen pressure 0.5 to 10 MPa, removal temperature: 0 - 100 °C; the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours; Or, the process of removing the aziridine protecting group is as follows: Removal conditions: The molar ratio of the acetic acid solution of HBr (33%) to the polymer repeating unit is 1 to 1000; removal reaction temperature: -20 to 100 °C; the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours.

7. The method for preparing a crystalline poly(ester amide) according to claim 1, characterized in that, The process of removing the aziridine protecting group is as follows: Removal conditions: The molar ratio of the acetic acid solution of HBr (33%) to the polymer repeating unit is 1 to 1000; removal reaction temperature: -20 to 100 °C; the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours.

8. The method for preparing a crystalline polyestersamide according to claim 1, wherein The process of removing the aziridine protecting group is as follows: Removal conditions: Red aluminum (sodium bis(2-methoxyethoxy)aluminum dihydride) is used as a catalyst, the molar ratio of red aluminum to the polymer repeating unit is 1 / 100 to 100 / 1, reaction temperature: 0 to 100 °C, the solvent used is selected from any one or a mixed solvent of toluene, dioxane, dichloromethane, chloroform, methanol, tetrahydrofuran, N,N-dimethylformamide, xylene, ethylene glycol dimethyl ether; the removal time is 1 - 99 hours.

9. A crystalline polyester amide prepared by the method according to any one of claims 1 to 8.

10. Use of the crystalline polyestersamide according to claim 9 in medicine, hydrogels, elastomers or smart materials.

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