Carbon dioxide-based ionic polycarbonate and preparation method and application thereof

Abstract

The application relates to a carbon dioxide-based ionic polycarbonate and a preparation method and application thereof. The ionic polycarbonate is obtained through one-pot one-step polymerization of a dihydroxy ionic liquid, a dihalogen alkane and carbon dioxide. The carbon dioxide pressure is 0.1-10 MPa, and the reaction temperature is 30-200 DEG C. Compared with traditional polycarbonates, the ionic polycarbonate contains ionic liquid segments on the main chain, and has good conductivity and antibacterial performance; compared with traditional ionic liquids, the ionic polycarbonate contains a large number of carbon dioxide-derived polar functional groups and rich cation groups in the skeleton, and has good stability and tunability. The synthesis process is simple, reproducible and controllable. The material has the characteristics of polycarbonates and polyionic liquids, has potential applications in the fields of chemical catalysis, separation and purification, electrochemical energy storage and biomedicine, and meets the green development concept.

Description

Technical Field

[0001] This invention relates to the field of polymer material synthesis technology, and in particular to a carbon dioxide-based ionic polycarbonate, its preparation method, and its application. Background Technology

[0002] Carbon dioxide, as an abundant and renewable green C1 feedstock, is beneficial for mitigating the greenhouse effect and achieving carbon cycling through its resource utilization. Synthesizing polymer materials from CO2 offers 100% atom economy and is considered a green and safe synthetic strategy. Polycarbonate synthesized from carbon dioxide exhibits good biocompatibility and biodegradability, avoiding the use of bisphenol A in traditional polycarbonate preparation methods, thus showing promising application prospects. However, the relatively limited functional groups on the molecular chain of traditional polycarbonate result in poor multifunctionality, restricting its widespread application.

[0003] Polyionic liquids are a class of polymers whose backbone contains ionic liquid structural units. They combine the properties of ionic liquids and polymers, exhibiting good thermal and chemical stability, ionic conductivity, structural designability and tunability, and processability. They have promising applications in energy devices, biomaterials, and smart devices.

[0004] However, traditional polycarbonate has problems with poor conductivity, antibacterial properties, stability, and tunability. Summary of the Invention

[0005] Based on the problems of poor conductivity, antibacterial properties, stability and tunability of traditional polycarbonates, this invention provides a carbon dioxide-based ionic polycarbonate, its preparation method and application.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] This invention first provides a carbon dioxide-based ionic polycarbonate containing ionic liquid segments and a biodegradable carbonate structure, the structural formula of which is shown in formula (Ⅰ):

[0008]

[0009] Wherein, R1 is the main structure of the dihydroxy ionic liquid, represented as HO-R1-OH, R2 is the main structure of the dihaloalkane, represented as X-R2-X, and n and m are both integers greater than 1.

[0010] The present invention also provides a method for preparing carbon dioxide-based ionic polycarbonate, wherein dihydroxy ionic liquid, dihaloalkane and carbon dioxide are used as monomers, and a polymerization reaction is carried out to prepare carbon dioxide-based ionic polycarbonate.

[0011] In one embodiment of the present invention, the preparation method of carbon dioxide-based ionic polycarbonate includes the following steps: first, an organic solvent, a dihydroxy ionic liquid, a dihaloalkane and a catalyst are added sequentially to the liner, then a high-pressure reactor is assembled, stirred and heated, carbon dioxide is introduced, a polymerization reaction is carried out, after the reaction is completed, the reactants are centrifuged, washed and purified, and the product is dried to obtain carbon dioxide-based ionic polycarbonate.

[0012] In one embodiment of the present invention, the cation of the dihydroxy ionic liquid is selected from one or a mixture of several of the following: imidazole dihydroxy cations, pyrrole dihydroxy cations, triazole dihydroxy cations, quaternary ammonium dihydroxy cations, quaternary phosphonium dihydroxy cations, guanidine salt dihydroxy ions, pyrazole dihydroxy cations, pyrimidine dihydroxy cations, pyrazine dihydroxy cations, azacyclobutane dihydroxy cations, tetrahydropyrrole dihydroxy cations, or piperidine dihydroxy cations.

[0013] The structure of the imidazole dihydroxy cation is shown below:

[0014]

[0015] The structure of pyrrole dihydroxy cations is shown below:

[0016]

[0017] The structure of the triazole dihydroxy cation is shown below:

[0018]

[0019] The structure of the quaternary ammonium dihydroxy cation is shown below:

[0020]

[0021] The structure of the quaternary phosphonium salt dihydroxy cation is shown below:

[0022]

[0023] The structure of the guanidine salt dihydroxy cation is shown below:

[0024]

[0025] The structure of the pyrazole dihydroxy cation is shown below:

[0026]

[0027] The structure of the pyridine dihydroxy cation is shown below:

[0028]

[0029] The structure of the pyrazine dihydroxy cation is shown below:

[0030]

[0031] The structure of the azacyclobutane dihydroxy cation is shown below:

[0032]

[0033] The structure of the tetrahydropyrrole dihydroxy cation is shown below:

[0034]

[0035] The structure of piperidine dihydroxy cations is shown below:

[0036]

[0037] In the above structural formula, n represents the number of C links. n is a positive integer and can be selected from 2 to 18. R1, R2, R3 and R4 represent other substituents.

[0038] In one embodiment of the present invention, the anion in the dihydroxy ionic liquid is selected from one or a mixture of several of the following: chloride ion, bromide ion, iodide ion, thiocyanate ion, acetate ion, nitrate ion, dichloroacetic acid ion, tetrafluoroborate ion, hexafluorophosphate ion, trifluoromethanesulfonate ion, or bis(trifluoromethanesulfonyl)imide ion.

[0039] The structure of the trifluoromethanesulfonate ion is shown below;

[0040]

[0041] The structure of the tetrafluoroborate ion is shown below;

[0042]

[0043] The structure of the hexafluorophosphate ion is shown below;

[0044]

[0045] The structure of the bis(trifluoromethanesulfonyl)imide ion is shown below;

[0046]

[0047] Therefore, in one embodiment of the present invention, the dihydroxy ionic liquid is one or a mixture of several of the following: imidazole dihydroxy ionic liquid, pyridine dihydroxy ionic liquid, quaternary ammonium dihydroxy ionic liquid, guanidine salt dihydroxy ionic liquid, and piperidine dihydroxy ionic liquid, and its molecular structure is as follows: Figure 1 As shown, Figure 1 The left side represents the cation type, and the right side represents the anion type. By selecting one or more ions from the left and right sides respectively and combining them, a dihydroxy ionic liquid can be obtained. In the left structure, n represents the number of C bonds, and n is a positive integer with a selection range of 2 to 18.

[0048] In one embodiment of the present invention, the dihaloalkane refers to an alkane containing two terminal halogen atoms. The present invention uses one or more of the following dihaloalkanes, with the following structural formulas.

[0049]

[0050] In the above structural formula, n represents the number of C atoms connected. n is a positive integer and can be selected from 2 to 18. X represents a halogen atom, such as a chlorine atom, a bromine atom, or an iodine atom.

[0051] In one embodiment of the present invention, the organic solvent is selected from one or a mixture of several of diethylene glycol dibutyl ether, N-methylpyrrolidone, tetraethylene glycol dimethyl ether, dipropylene glycol dimethyl ether, and diphenylmethane, and the concentration of the ionic liquid in the organic solvent is 0.2 to 3.0 g / mL.

[0052] In one embodiment of the present invention, organic solvents may not be required in the preparation of carbon dioxide-based ionic polycarbonate.

[0053] In one embodiment of the invention, the polymerization reaction occurs in the presence of a catalyst selected from one or more of 4-methyloxycholine (MNO), triazabicyclo(TBD), diazabicyclo(DBU), triethylamine (TEA), potassium carbonate, cesium carbonate, potassium hydroxide, cesium hydroxide monohydrate, or potassium tert-butoxide.

[0054] In one embodiment of the present invention, the polymerization reaction conditions are: carbon dioxide pressure of 0.1 to 10 MPa, reaction temperature of 60 to 200°C, and reaction time of 2 to 24 hours.

[0055] In one embodiment of the present invention, during the polymerization reaction, the molar ratio of the dihydroxy ionic liquid, the dihaloalkane, and the catalyst is 1:0.5 to 2:0.5 to 4.

[0056] In one embodiment of the present invention, the washing and purification step is as follows: the reactants are centrifuged and poured into diethyl ether, stirred, the supernatant is discarded, the mixture is circulated three times, and after vacuum drying, a mixture to be purified is obtained. The mixture is then dissolved in deionized water, ammonium hexafluorophosphate is added, and the mixture is washed three times with deionized water. The volume ratio of the supernatant, diethyl ether, and deionized water is 1:2:5, and the mass ratio of the mixture to be purified to ammonium hexafluorophosphate is 1:5.

[0057] In one embodiment of the present invention, the method for preparing carbon dioxide-based ionic polycarbonate includes the following steps:

[0058] (1) Select a suitable organic solvent to prepare a 0.5-3 mol / L solution of the dihydroxy ionic liquid;

[0059] (2) Add 0.5 to 4 times the molar amount of dihaloalkane and 0.5 to 4 times the molar amount of dihydroxy ionic liquid to the dihydroxy ionic liquid solution prepared in reaction step (1) in sequence, and obtain a homogeneous precursor solution by ultrasonic treatment;

[0060] (3) Inject the precursor solution prepared in reaction step (2) into the reaction vessel, purge the air with carbon dioxide, the carbon dioxide pressure is 0.1-10 MPa, the reaction temperature is 60-200℃, the reaction time is 2-24 h, wash, purify and dry to obtain carbon dioxide-based ionic polycarbonate.

[0061] This invention also provides a carbon dioxide-based ionic polycarbonate obtained based on the above preparation method. This carbon dioxide-based ionic polycarbonate has adjustable hydrophilicity / hydrophobicity and molecular chain flexibility; it achieves the utilization of carbon dioxide; and it exhibits good antibacterial properties.

[0062] The present invention also provides applications of carbon dioxide-based ionic polycarbonate obtained based on the above preparation method, wherein the carbon dioxide-based ionic polycarbonate is used as a functional material in the fields of flexible electronic devices and biomedicine.

[0063] This invention achieves tunable performance of ionic polycarbonates by utilizing the designability of ionic liquids and dihaloalkane structures. Specifically, the flexibility of the polymer molecular chain can be controlled by adjusting the alkyl chain length of the dihydroxy ionic liquid and the dihaloalkane, thereby controlling the thermodynamic properties. The abundant carbon dioxide-derived polar functional groups and rich cationic groups in the polymer backbone give this ionic polyurea excellent ionic conductivity and antibacterial properties, showing potential applications in energy storage sensing and biomedicine. The carbon dioxide-based ionic polycarbonate described in this invention is simple to prepare, versatile in function, has a wide range of applications, and is highly designable, while also aligning with the concept of green development.

[0064] This invention copolymerizes carbon dioxide and a functional ionic liquid to prepare an ionic carbon dioxide-based polycarbonate, possessing the dual properties of both polyionic liquids and carbon dioxide-based polymers. It has significant application value in flexible electronic devices and the biomedical field. Compared to traditional polycarbonates, the ionic polycarbonate backbone contains ionic liquid segments, exhibiting excellent conductivity and antibacterial properties. Compared to traditional ionic liquids, the ionic polycarbonate backbone contains a large number of carbon dioxide-derived polar functional groups and abundant cationic groups, resulting in better stability and tunability. The synthesis process of this invention is simple, reproducible, and highly controllable. This material combines the properties of both polycarbonates and polyionic liquids, showing potential applications in chemical catalysis, separation and purification, electrochemical energy storage, and biomedicine, while also aligning with the concept of green development.

[0065] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0066] (1) The carbon dioxide-based ionic polycarbonate synthesis route in this invention avoids the use of phosgene in the traditional phosgene method. The preparation method is simple, efficient, green and environmentally friendly, in line with the concept of green development, and has the value of promotion and application.

[0067] (2) The carbon dioxide-based ionic polycarbonate prepared by the present invention has the characteristics of an ionic polymer compared with traditional nonionic polycarbonate.

[0068] (3) The carbon dioxide-based ionic polycarbonate prepared by this invention has good structural tunability. By changing the types of anions and cations of the dihydroxy ionic liquid and the types of dihaloalkanes, the thermodynamic properties, mechanical properties, hydrophilicity and hydrophobicity, ionic conductivity and antibacterial properties of the carbon dioxide-based ionic polycarbonate can be controlled;

[0069] (4) The carbon dioxide-based ionic polycarbonate prepared by the present invention realizes the resource utilization of carbon dioxide, which has positive significance for mitigating the greenhouse effect. Attached Figure Description

[0070] Figure 1 This is a schematic diagram of the structure of a dihydroxy ionic liquid.

[0071] Figure 2 The infrared spectrum of the imidazole-type carbon dioxide-based ionic polycarbonate prepared in Example 1.

[0072] Figure 3 The 1H NMR spectrum of the imidazole-type carbon dioxide-based ionic polycarbonate prepared in Example 1.

[0073] Figure 4The antibacterial properties of the imidazole-type carbon dioxide-based ionic polycarbonate prepared in Example 3 are shown in (a) as the control group and (b) as the experimental group.

[0074] Figure 5 Thermogravimetric curve of the quaternary ammonium salt-type carbon dioxide-based ionic polycarbonate prepared in Example 4. Detailed Implementation

[0075] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make some non-essential improvements and adjustments based on the above description of the present invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0076] Example 1

[0077] This embodiment provides a method for preparing carbon dioxide-based ionic polycarbonate:

[0078] 2 g of imidazole-type dihydroxy ionic liquid (1,3-di(hydroxyethyl)-imidazolium bromide) and 1.05 molar fraction of 1,4-dibromobutane were dissolved in 5 mL of N-methylpyrrolidone, and 1 molar fraction of cesium carbonate was added. The above precursor solution was injected into a reactor, and the mixture was purged with carbon dioxide for 5 min to remove air. The temperature was then raised to 60 °C, and finally, 1 MPa of CO2 was introduced and the mixture was stirred for 6 h. The mixture was washed several times with diethyl ether, and the diethyl ether was removed by rotary evaporation to obtain the reaction product to be purified. The reaction product to be purified contained imidazole-type carbon dioxide-based ionic polycarbonate and imidazole-type dihydroxy ionic liquid. The reaction product to be purified was dissolved in water, and 5 times the mass of the reaction product to be purified ammonium hexafluorophosphate was added. The precipitate was washed with deionized water to obtain imidazole-type carbon dioxide-based ionic polycarbonate.

[0079] Figure 2 The infrared spectrum of the imidazole-type carbon dioxide-based ionic polycarbonate is shown above. The corresponding characteristic peaks prove that the imidazole-type carbon dioxide-based ionic polycarbonate was successfully prepared.

[0080] Figure 3 The 1H NMR spectrum of the above imidazole-type carbon dioxide-based ionic polycarbonate shows that the imidazole-type carbon dioxide-based ionic polycarbonate was successfully prepared.

[0081] Example 2

[0082] This embodiment provides a method for preparing carbon dioxide-based ionic polycarbonate:

[0083] 2 g of imidazole-type dihydroxy ionic liquid (1,3-di(hydroxyethyl)-imidazolium bromide) and 1.05 molar fraction of 1,4-dibromobutane were dissolved in 5 mL of N-methylpyrrolidone, and 0.5 molar fraction of cesium carbonate was added. The above precursor solution was injected into a reactor, and the mixture was purged with carbon dioxide for 5 min to remove air. The temperature was then raised to 100 °C, and finally, 0.1 MPa of CO2 was introduced and the mixture was stirred for 24 h. The mixture was washed several times with diethyl ether, and the diethyl ether was removed by rotary evaporation to obtain the reaction product to be purified. The reaction product to be purified contained imidazole-type carbon dioxide-based ionic polycarbonate and imidazole-type dihydroxy ionic liquid. The reaction product to be purified was dissolved in water, and 5 times the mass of the reaction product to be purified ammonium hexafluorophosphate was added. The precipitate was washed with deionized water to obtain imidazole-type carbon dioxide-based ionic polycarbonate.

[0084] Example 3

[0085] This embodiment provides a method for preparing carbon dioxide-based ionic polycarbonate:

[0086] Dissolve 2 g of imidazole-type dihydroxy ionic liquid (1,3-di(hydroxyethyl)-imidazolium bromide) and 1.05 molar fraction of 1,4-dibromobutane in 5 mL of N-methylpyrrolidone, and add 1 molar fraction of cesium carbonate. Inject the precursor solution into a reactor, purge with carbon dioxide for 5 min to remove air, raise the temperature to 60 °C, and finally introduce CO2 at 3 MPa and stir for 6 h. Wash repeatedly with diethyl ether, remove the ether by rotary evaporation, dissolve the product in water, add 5 times the product mass of ammonium hexafluorophosphate, and wash the precipitate with deionized water to obtain imidazole-type carbon dioxide-based ionic polycarbonate.

[0087] Figure 4 The antibacterial performance of the aforementioned imidazole-type carbon dioxide-based ionic polycarbonate was investigated. Specifically, an imidazole-type carbon dioxide-based ionic polycarbonate was prepared as a 1 mg / mL PBS solution, with 5 wt% dimethyl sulfoxide added as a solubilizer to improve solubility. Bacterial suspension was added dropwise to the prepared sample solution and incubated at 37°C for 4 h. Then, 10 μL of the bacterial suspension was taken out, dropped onto an agar plate, and spread evenly. After incubation at 37°C for 12 h, the number of surviving bacterial colonies was recorded. Each test was repeated three times, and the antibacterial rate was calculated. Figure a represents the control group experiment, and figure b represents the experimental group data. The results show that, under the influence of *S. spp.*, imidazole-type carbon dioxide-based ionic polycarbonate exhibits excellent antibacterial effects against *S. spp.*.

[0088] Example 4

[0089] This embodiment provides a method for preparing carbon dioxide-based ionic polycarbonate:

[0090] 2 g of quaternary ammonium salt-type dihydroxy ionic liquid (N,N-dimethylethylene glycol amiodarone) and 1.05 molar fraction of 1,4-dibromobutane were dissolved in 5 mL of N-methylpyrrolidone, and 4 molar fraction of cesium carbonate was added. The above precursor solution was injected into a reactor, purged with carbon dioxide for 5 min to remove air, and then the temperature was raised to 100 °C. Finally, CO2 at 5 MPa was introduced and the reaction was stirred for 24 h. After washing with ether and water several times, and drying, quaternary ammonium salt-type carbon dioxide-based ionic polycarbonate was obtained.

[0091] Figure 5 The thermogravimetric curves of the above-mentioned quaternary ammonium carbon dioxide-based ionic polycarbonate prove the existence of the carbonate structure.

[0092] Example 5

[0093] This embodiment provides a method for preparing carbon dioxide-based ionic polycarbonate:

[0094] Dissolve 2 g of imidazole-type dihydroxy ionic liquid (1,3-di(hydroxyethyl)-imidazolium bromide) and 0.5 molar fraction of 1,4-dibromobutane in 5 mL of N-methylpyrrolidone, and add 0.5 molar fraction of cesium carbonate. Inject the precursor solution into a reactor, purge with carbon dioxide for 5 min to remove air, raise the temperature to 30 °C, and finally introduce CO2 at 0.1 MPa and stir for 2 h. Wash repeatedly with diethyl ether, remove the ether by rotary evaporation, dissolve the product in water, add 5 times the product mass of ammonium hexafluorophosphate, and wash the precipitate with deionized water to obtain imidazole-type carbon dioxide-based ionic polycarbonate.

[0095] Example 6

[0096] This embodiment provides a method for preparing carbon dioxide-based ionic polycarbonate:

[0097] Dissolve 2 g of imidazole-type dihydroxy ionic liquid (1,3-di(hydroxyethyl)-imidazolium bromide) and 4 molar fractions of 1,4-dibromobutane in 5 mL of N-methylpyrrolidone, and add 4 molar fractions of cesium carbonate. Pour the above precursor solution into a reactor, purge with carbon dioxide for 5 min to remove air, raise the temperature to 120 °C, and finally introduce CO2 at 5 MPa and stir for 48 h. Wash repeatedly with diethyl ether, remove the diethyl ether by rotary evaporation, and obtain the product to be purified. Dissolve the product in water, add 5 times the product mass of ammonium hexafluorophosphate, and wash the precipitate with deionized water to obtain imidazole-type carbon dioxide-based ionic polycarbonate.

[0098] Example 7

[0099] This embodiment provides a method for preparing carbon dioxide-based ionic polycarbonate:

[0100] Dissolve 1 g of imidazole-type dihydroxy ionic liquid (1,3-di(hydroxyethyl)-imidazolium bromide) and 1.05 molar fraction of 1,4-dibromobutane in 5 mL of N-methylpyrrolidone, and add 1 molar fraction of cesium carbonate. Inject the precursor solution into a reactor, purge with carbon dioxide for 5 min to remove air, raise the temperature to 120 °C, and finally introduce CO2 at 3 MPa and stir for 24 h. Wash repeatedly with diethyl ether, remove the ether by rotary evaporation, dissolve the product in water, add 5 times the product mass of ammonium hexafluorophosphate, and wash the precipitate with deionized water to obtain imidazole-type carbon dioxide-based ionic polycarbonate.

[0101] Example 8

[0102] This embodiment provides a method for preparing carbon dioxide-based ionic polycarbonate:

[0103] 2 g of imidazole-type dihydroxy ionic liquid (1,3-di(hydroxyethyl)-imidazolium bromide) and 3 molar fractions of 1,4-dibromobutane were mixed, and 1 molar fraction of cesium carbonate was added. The above precursor solution was injected into a reactor, and the mixture was purged with carbon dioxide for 5 min to remove air. The temperature was then raised to 80 °C, and finally, 0.1 MPa of CO2 was introduced and the mixture was stirred for 6 h. The mixture was washed with diethyl ether multiple times, and the diethyl ether was removed by rotary evaporation. The product was dissolved in water, and 5 times the mass of ammonium hexafluorophosphate was added. The precipitate was washed with deionized water to obtain imidazole-type carbon dioxide-based ionic polycarbonate.

[0104] Example 9

[0105] This embodiment provides a method for preparing carbon dioxide-based ionic polycarbonate:

[0106] 2 g of imidazole-type dihydroxy ionic liquid (1,3-di(hydroxyethyl)-imidazolium bromide) and 1.05 molar fraction of 1,4-dibromobutane were dissolved in 5 mL of N-methylpyrrolidone, and 0.5 molar fraction of potassium carbonate was added. The above precursor solution was injected into a reactor, and the mixture was purged with carbon dioxide for 5 min to remove air. The temperature was then raised to 100 °C, and finally, 0.1 MPa of CO2 was introduced and the mixture was stirred for 24 h. The mixture was washed several times with diethyl ether, and the diethyl ether was removed by rotary evaporation to obtain the product to be purified. The product was dissolved in water, and 5 times the mass of ammonium hexafluorophosphate was added. The precipitate was washed with deionized water to obtain imidazole-type carbon dioxide-based ionic polycarbonate.

[0107] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A method for preparing carbon dioxide-based ionic polycarbonate, characterized in that, The process includes the following steps: first, organic solvent, dihydroxy ionic liquid, dihaloalkane and catalyst are added to the liner in sequence, then a high-pressure reactor is assembled, stirred and heated, carbon dioxide is introduced, and a polymerization reaction is carried out. After the reaction is completed, the reactants are centrifuged, washed and purified, and the product is dried to obtain carbon dioxide-based ionic polycarbonate. The organic solvent is N-methylpyrrolidone, the dihydroxy ionic liquid is 1,3-di(hydroxyethyl)-imidazolium bromide, the dihaloalkane is 1,4-dibromobutane, and the catalyst is cesium carbonate.

2. The method for preparing carbon dioxide-based ionic polycarbonate according to claim 1, characterized in that, The concentration of ionic liquids in organic solvents is 0.5–3.0 g / mL.

3. The method for preparing carbon dioxide-based ionic polycarbonate according to claim 1, characterized in that, The polymerization conditions are: carbon dioxide pressure 0.1–10 MPa, reaction temperature 60–200 °C, and reaction time 2–24 h. During the polymerization reaction, the molar ratio of the dihydroxy ionic liquid, the dihaloalkane, and the catalyst is 1:0.5 to 2:0.5 to 4.

4. The method for preparing carbon dioxide-based ionic polycarbonate according to claim 1, characterized in that, The preparation method includes the following steps: (1) Select an organic solvent to prepare a 0.5-3 mol / L solution of the dihydroxy ionic liquid; (2) Add 0.5 to 2 times the molar amount of dihaloalkane and 0.5 to 4 times the molar amount of catalyst of dihydroxy ionic liquid to the dihydroxy ionic liquid solution prepared in step (1), and obtain a homogeneous precursor solution by ultrasonic treatment; (3) The precursor solution prepared in step (2) is injected into the reactor, the air is purged with carbon dioxide, the carbon dioxide pressure is 0.1-10 MPa, the reaction temperature is 60-200 ℃, the reaction time is 2-24 h, and the product is washed, purified and dried to obtain carbon dioxide-based ionic polycarbonate.

5. A carbon dioxide-based ionic polycarbonate, characterized in that, The carbon dioxide-based ionic polycarbonate obtained by any one of claims 1 to 4 contains ionic liquid segments and a biodegradable carbonate structure, and its structural formula is shown in formula (I): Equation (Ⅰ) Where R1 is the main structure of the dihydroxy ionic liquid, R2 is the main structure of the dihaloalkane, and n and m are both integers greater than 1. The carbon dioxide-based ionic polycarbonate has adjustable hydrophilicity / hydrophobicity and molecular chain flexibility.

6. The application of the carbon dioxide-based ionic polycarbonate according to claim 5, characterized in that, The carbon dioxide-based ionic polycarbonate is used as a functional material in flexible electronic devices.

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