A linear comb-shaped carbon dioxide copolymer containing hydrophilic branches and its preparation method

Abstract

The application belongs to the field of high polymer materials, and particularly relates to a linear comb-shaped carbon dioxide copolymer containing hydrophilic branches and a preparation method thereof. The linear comb-shaped carbon dioxide copolymer containing hydrophilic branches is prepared through two-step reaction. In the first step, carbon dioxide-based polymer main chains are prepared by taking epoxide compound 1, epoxide compound 2 and carbon dioxide as comonomers. By adjusting the synthesis process route, the synthesis of random and block structure polymer main chains can be realized. The double bond in the epoxide compound 1 can be used as a functionalization site. By adjusting the polymer main chain components, the material performance and the number of functionalization sites can be controlled. In the second step, the polyether hydrophilic side chain with an amine group on one side is grafted onto the polymer main chain through a post-functionalization reaction. In addition, by adjusting the grafting rate of the polymer side chain and the molecular chain length of the polyether side chain, the hydrophilicity of the material can be controlled. The introduction of the polyether side chain improves the hydrophilicity of the material and greatly expands the application field of the material.

Description

Technical Field

[0001] This invention belongs to the field of polymer materials, specifically relating to a linear comb-shaped carbon dioxide copolymer containing hydrophilic side chains and its preparation method. Background Technology

[0002] Carbon dioxide is an abundant, inexpensive, and non-toxic renewable resource. Efficient and green technologies for converting carbon dioxide into industrial products have attracted increasing attention. The copolymerization of carbon dioxide and epoxides to prepare polycarbonates (PCs) is a promising approach to achieving efficient carbon dioxide utilization. Among the many types of carbon dioxide-based polycarbonate materials currently being developed, polypropylene carbonate (PPC) is a representative material. As a fully biodegradable material, PPC is a polymer prepared by copolymerizing CO2 and propylene oxide (PO), exhibiting excellent barrier properties and transparency. PPC is also a carbon dioxide-based polycarbonate material that is currently being mass-produced, with companies such as Novomer (USA), Empower Materials, and SK Chemicals (South Korea) successfully commercializing it. In addition, poly(cyclohexene carbonate) (PCHC) is another promising carbon dioxide-based polycarbonate material, prepared by copolymerizing CO2 and cyclohexane oxide (CHO). Compared to PPC, PCHC introduces an aliphatic ring structure into its molecular chain, increasing the rigidity of the molecular chain and thus exhibiting higher heat resistance.

[0003] Although carbon dioxide-based polycarbonate materials have made significant progress, some problems still exist. For example, they exhibit poor hydrophilicity and lack refined topological design. This is mainly attributed to the lack of functionalization sites in the polymer, which limits subsequent chemical modification and further restricts their application areas. Introducing a third monomer with functional groups into the polymer is an effective means of introducing functionalization sites for chemical modification, thereby improving material properties and expanding its application areas. For example, 4,5-epoxy-1-cyclohexene (CHDO) is a typical example of such compounds, and its introduction as a comonomer into carbon dioxide-based polycarbonate provides the possibility for post-functionalization of the polymer. Meier et al. attempted to prepare various binary or ternary copolymers using carbon dioxide, CHDO, phthalic anhydride (PA), and cyclohexene oxide (CHO) as reactive monomers. Among them, the glass transition temperatures of the CHDO / CO2 and CHDO / PA binary copolymers reached 115℃ and 128℃, respectively. Furthermore, based on this research, a cross-linked CHDO / CO2 copolymer was prepared using trimethylolpropane tris(3-mercaptopropionate) as a cross-linking agent, showing promise as a coating material. Some research groups have also conducted preliminary explorations into the modification of double bonds in polymers containing CHDO structural units. For example, halogen atoms or hydrophilic groups are added to the polymer backbone via post-functionalization reactions. However, these methods often only introduce atoms or functional groups into the molecular chain without further refined control and design of the topology, resulting in limited modification effects. Linear branched structures can reduce polymer melt viscosity, providing superior processing properties and enabling them to become novel polymer materials. Due to the different properties of linearly branched polymers compared to linear polymers, they have wide applications in photocurable materials, coating additives, tissue engineering, and biomedicine. In summary, there are currently few reports on the improvement of hydrophilicity and the design of molecular chain topology in CHDO multi-component polymers.

[0004] The structure of 4,5-epoxy-1-cyclohexene (CHDO) is as follows: Summary of the Invention

[0005] The main content of this invention is to address the shortcomings of existing technologies by providing a linear comb-shaped carbon dioxide copolymer containing hydrophilic side chains and its preparation method. The linear comb-shaped carbon dioxide copolymer containing hydrophilic side chains of this invention is prepared through a two-step reaction. The first step involves using epoxy compound 1, epoxy compound 2, and carbon dioxide as comonomers, and by adjusting the synthesis process, achieving both random and block structures of the carbon dioxide-based polymer backbone. The second step involves grafting hydrophilic polyether side chains with amine end groups onto the polymer backbone through a post-functionalization reaction. The double bonds in epoxy compound 1 can serve as functionalization sites, and the material properties and the number of functionalization sites can be controlled by adjusting the composition of the polymer backbone. Furthermore, the hydrophilicity of the material can be controlled by adjusting the number of polymer side chains grafted and the molecular chain length of the side-chain polyethers. The introduction of polyether side chains improves the hydrophilicity of the material and greatly expands its application fields.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A linear comb-shaped carbon dioxide copolymer containing hydrophilic side chains is characterized by a linear comb-shaped polymer structure comprising a carbon dioxide-based polymer backbone and polyether side chains. The polymer backbone involves both random and block structures. By adjusting the polymer components and designing the structure, the material properties and the number of post-functionalization sites can be controlled. The polyether side chains are grafted onto the polymer backbone through post-functionalization. By controlling the molecular weight and type of the side-chain polyethers, the hydrophilicity of the material can be controlled. Its structural formula is as follows:

[0008]

[0009] In the formula:

[0010] m is a non-zero natural number;

[0011] n is a non-zero natural number;

[0012] x is a natural number from 0 to 10;

[0013] y is a natural number from 0 to 10.

[0014] R1 is selected from One of them.

[0015] R2 is selected from One of them.

[0016] R3 is selected from One of them.

[0017] The method for preparing a linear comb-shaped carbon dioxide copolymer containing hydrophilic side chains is characterized by being prepared through a two-step reaction. The first step is to prepare a random or block structure carbon dioxide-based terpolymer backbone, and the second step is to graft hydrophilic side chains onto the polymer backbone through a post-functionalization reaction.

[0018] The method for preparing a random carbon dioxide-based terpolymer backbone is characterized by the following steps: Under anhydrous and oxygen-free conditions, epoxy compound 1 and epoxy compound 2 are added to a constant-pressure feeding tank, an initiator and a catalyst are added to a high-pressure reactor, and then high-purity carbon dioxide gas is introduced into the high-pressure reactor. The epoxy compound in the constant-pressure feeding tank is gradually added dropwise to the reactor, and the mixture is heated to carry out a polymerization reaction. After the reaction is completed, the polymer sample is cooled to room temperature, the pressure is released, and chloroform is added to the reactor to completely dissolve the polymer. The obtained product is precipitated with anhydrous methanol, dissolved, and precipitated repeatedly, and then vacuum dried to constant weight to obtain the purified carbon dioxide-based terpolymer backbone.

[0019] The method for preparing a block-structured carbon dioxide-based terpolymer backbone is characterized by the following steps: under anhydrous and oxygen-free conditions, epoxy compound 1 is added to a constant-pressure feeding tank, initiator and catalyst are added to a high-pressure reactor, and then high-purity carbon dioxide gas is introduced. The epoxy compound in the constant-pressure feeding tank is gradually added dropwise to the reactor, and the mixture is heated to carry out the first polymerization reaction. After the reaction has been completed, epoxy compound 2 is pumped into the reactor using a high-pressure injection pump to continue the second polymerization reaction. After the reaction is completed, the polymer sample is cooled to room temperature, the pressure is released, and chloroform is added to the reactor to completely dissolve the polymer. The obtained product is precipitated with anhydrous methanol, dissolved, and precipitated again, and this process is repeated multiple times. The product is then vacuum dried to constant weight to obtain the purified carbon dioxide-based terpolymer backbone.

[0020] The method for preparing a linear comb-shaped carbon dioxide copolymer containing hydrophilic side chains by post-functionalization reaction to branch hydrophilic side chains onto the polymer backbone is characterized by comprising the following steps: dissolving the prepared carbon dioxide-based terpolymer sample in dry chloroform; adding a polyether containing primary amine groups at the chain ends to the solution and stirring the reaction at room temperature for a period of time; after the reaction is complete, adding the product dropwise to excess diethyl ether, precipitating the precipitate, filtering, and repeating this process twice; and drying under vacuum to constant weight to obtain the purified linear comb-shaped carbon dioxide copolymer containing hydrophilic side chains.

[0021] Furthermore, the epoxy compound 1 is an epoxy compound containing an unsaturated aliphatic ring structure, mainly including one of 4,5-epoxy-1-cyclohexene (CHDO), 4,5-epoxy-3-methyl-1-cyclohexene, 4,5-epoxy-3-ethyl-1-cyclohexene, 4,5-epoxy-3-isopropyl-1-cyclohexene, 4,5-epoxy-3,6-dimethyl-1-cyclohexene, and 4,5-epoxy-3,6-diethyl-1-cyclohexene, with the following structure:

[0022]

[0023] The monomer of epoxy compound 2 is one of ethylene oxide, epichlorohydrin, and epibutylene oxide, with the following structure:

[0024]

[0025] The molar ratio of epoxy compound 1 to epoxy compound 2 is 0.1 to 9:1.

[0026] Furthermore, in the post-functionalization reaction, the branched molecule is one of: methoxy polyethylene glycol-amino, methoxy polypropylene glycol-amino, or methoxy polytetrahydrofuran-amino. The structure is as follows:

[0027]

[0028] Furthermore, the catalyst is commercially available Zn3[Co(CN)6]2, and the molar ratio of the catalyst to the epoxide compound is 1:200 to 20000. The total amount of the epoxide monomer is the total amount of epoxide compound 1 and epoxide compound 2.

[0029] Furthermore, the chain initiator is one of benzyl alcohol, ethylene glycol, propylene glycol, butanediol, polyethylene glycol 400, and polypropylene glycol 600, and the molar ratio of the chain initiator to the total amount of epoxy monomer is 1:200 to 2000.

[0030] Furthermore, the main-chain polymer synthesis reaction temperature is 50-150℃, the main-chain polymer synthesis reaction time is 4-12h, and the carbon dioxide pressure for main-chain polymer synthesis is 0.5-3MPa.

[0031] Furthermore, the post-functionalization reaction temperature is 10–60°C, and the post-functionalization reaction time is 6–24 h.

[0032] Furthermore, the hydrophilic side grafting rate of the linear comb-shaped carbon dioxide copolymer containing hydrophilic branches is adjustable, with a grafting rate of 10–90 mol%.

[0033] Furthermore, the linear comb-shaped carbon dioxide copolymer containing hydrophilic branches has a number-average molecular weight of 10.0–50.0 kg / mol;

[0034] Furthermore, the glass transition temperature of the linear comb-shaped carbon dioxide copolymer containing hydrophilic branches can be adjusted within the range of 37–120°C.

[0035] Furthermore, the initial thermal decomposition temperature (T) of linear comb-shaped carbon dioxide copolymers containing hydrophilic branches... d,5％ The temperature can be adjusted within the range of 200 to 280℃.

[0036] The beneficial effects of this invention are:

[0037] (1) The linear comb-shaped carbon dioxide copolymer containing hydrophilic side chains described in this invention improves the hydrophilicity of carbon dioxide-based polycarbonate.

[0038] (2) The molecular structure of the linear comb-shaped carbon dioxide copolymer containing hydrophilic side chains described in this invention can be designed, and copolymers with different topological structures can be synthesized by adjusting the synthesis process route or the grafting rate of hydrophilic side chains, thereby broadening the application field of the material.

[0039] (3) The preparation route of the linear comb-shaped carbon dioxide copolymer containing hydrophilic branches described in this invention is efficient, low-energy and waste-free, and is an atom-economical route. At the same time, the catalysts and raw materials used are inexpensive and readily available, making it suitable for industrial production. Attached Figure Description

[0040] Figure 1 The GPC spectrum of the sample from Example 1;

[0041] Figure 2 The image shows the GPC spectrum of the sample from Example 4.

[0042] Figure 3 The image shows the GPC spectrum of the sample from Example 5.

[0043] Figure 4 For the sample of Example 1 1 H NMR spectrum.

[0044] Figure 5 For the sample of Example 2 1 H NMR spectrum.

[0045] Figure 6 For the sample of Example 3 1 H NMR spectrum.

[0046] Figure 7 For the sample of Example 4 1 H NMR spectrum.

[0047] Figure 8 For the sample of Example 5 1 H NMR spectrum.

[0048] Figure 9 The diagram shows the water contact angle of samples from Examples 1-5. Detailed Implementation

[0049] The technical solution of the present invention will be further described below through embodiments.

[0050] Unless otherwise stated, the terms used in this invention generally have the meanings commonly understood by those skilled in the art.

[0051] In the following embodiments, various processes and methods not described in detail are conventional methods known in the art. Furthermore, due to the diversity of polymer composition ratios and structures, not all preparation methods are described in detail; instead, typical examples are used to illustrate the specific process steps of the present invention.

[0052] Examples 1-2 are examples of methods for preparing the backbone of a random structure carbon dioxide-based terpolymer; Example 3 is an example of a method for preparing the backbone of a block structure carbon dioxide-based terpolymer; Examples 4 and 5 are examples of linear comb-shaped carbon dioxide copolymers containing hydrophilic branches and their preparation methods.

[0053] Example 1

[0054] Under anhydrous and oxygen-free conditions, 19.2 g (0.2 mol) of 4,5-epoxy-1-cyclohexene and 11.6 g (0.2 mol) of propylene oxide were added to a constant-pressure feeder. Polyethylene glycol-800 (0.8 g, 1 mmol) and catalyst Zn3[Co(CN)6]2 (0.125 g, 0.2 mmol) were added to a 100 mL high-pressure reactor. The temperature was raised to 80 °C, and high-purity carbon dioxide gas was introduced to a pressure of 1 MPa. The epoxy compound from the constant-pressure feeder was then gradually added dropwise to the reactor. The high-pressure reactor was placed in a heating mantle and heated to 100 °C for polymerization. After 10 h of reaction, the reactor was cooled to room temperature, and excess carbon dioxide was removed from the reaction system to reduce the pressure inside the reactor to atmospheric pressure. The polymer was completely dissolved in chloroform added to the reactor. The resulting product was precipitated with anhydrous methanol, dissolved, and precipitated repeatedly. The product was then vacuum dried to constant weight to obtain the purified random carbon dioxide-based terpolymer backbone. GPC testing showed that the polymer's number-average molecular weight was 23.7 kg / mol, and its molecular weight distribution was 2.68. Thermal performance testing showed that the obtained random carbon dioxide-based terpolymer had a glass transition temperature of 80℃ and an initial thermal decomposition temperature of 252℃. The material can be used as a general-purpose plastic for preparing bottles or sheets. Furthermore, the introduction of 4,5-epoxy-1-cyclohexene improved the material's rigidity and heat resistance, while also introducing functionalized sites (double bonds), laying the foundation for post-functionalization modification.

[0055] The GPC spectrum of the sample in Example 1 is as follows: Figure 1 As shown; the GPC spectrum of the sample exhibits a single-peak distribution and a narrow molecular weight distribution. The 1H NMR spectrum of the sample is shown below. Figure 4 As shown in the figure, the corresponding characteristic peaks are assigned to the corresponding peaks.

[0056] Example 2

[0057] Under anhydrous and oxygen-free conditions, 19.2 g (0.2 mol) of 4,5-epoxy-1-cyclohexene and 5.8 g (0.1 mol) of propylene oxide were added to a constant-pressure feeder. Polyethylene glycol-800 (0.8 g, 1 mmol) and catalyst Zn3[Co(CN)6]2 (0.094 g, 0.15 mmol) were added to a 50 mL high-pressure reactor. High-purity carbon dioxide gas was introduced to a pressure of 1 MPa. The epoxy compound from the constant-pressure feeder was gradually added dropwise to the reactor. The high-pressure reactor was placed in a heating mantle and heated to 100 °C for polymerization. After 10 h of reaction, the reactor was cooled to room temperature, and excess carbon dioxide was removed to reduce the pressure inside the reactor to atmospheric pressure. Chloroform was added to the reactor to completely dissolve the polymer. The resulting product was precipitated with anhydrous methanol, dissolved, and precipitated repeatedly. The product was then vacuum dried to constant weight to obtain a purified random-structure carbon dioxide-based terpolymer. GPC testing showed that the polymer's number-average molecular weight was 24.8 kg / mol, and its molecular weight distribution was 2.54. Thermal performance testing indicated that the obtained random-structure carbon dioxide-based terpolymer had a glass transition temperature of 98℃ and an initial thermal decomposition temperature of 259℃. The material can be used as a general-purpose plastic for preparing bottles or sheets. Furthermore, the introduction of 4,5-epoxy-1-cyclohexene improved the material's rigidity and heat resistance, while also introducing functionalized sites (double bonds), laying the foundation for post-functionalization modification.

[0058] Sample of Example 2 1 HNMR spectrum as follows Figure 5 As shown in the figure, the corresponding characteristic peaks are assigned to the corresponding peaks.

[0059] Example 3

[0060] Under anhydrous and oxygen-free conditions, 19.6 g (0.2 mol) of 4,5-epoxy-1-cyclohexene was added to a constant-pressure feeder, while 0.8 g (1 mmol) of polyethylene glycol-800 and 0.125 g (0.2 mmol) of catalyst Zn3[Co(CN)6]2 were added to a 50 mL high-pressure reactor. High-purity carbon dioxide gas was introduced to a pressure of 1 MPa, and the 4,5-epoxy-1-cyclohexene from the constant-pressure feeder was gradually added dropwise to the reactor. The high-pressure reactor was placed in a heating mantle and heated to 100 °C for polymerization. After 10 h of reaction, 11.6 g (0.2 mol) of propylene oxide was injected into the reactor using a high-pressure injection pump, and the reaction continued for another 5 h. After the reaction was completed, the reactor was cooled to room temperature, and excess carbon dioxide was removed from the reaction system to reduce the pressure inside the reactor to atmospheric pressure. Trichloromethane was added to the reactor to completely dissolve the polymer. The resulting product was precipitated with anhydrous methanol, dissolved, and precipitated repeatedly. The product was then vacuum dried to constant weight to obtain a purified block-structured carbon dioxide-based terpolymer. GPC testing showed that the polymer's number-average molecular weight was 28.9 kg / mol, and its molecular weight distribution was 2.25. Thermal performance testing showed that the obtained block-structured carbon dioxide-based terpolymer had glass transition temperatures of 43℃ and 96℃, and an initial thermal decomposition temperature of 218℃. The material can be used as a general-purpose plastic for preparing bottles or sheets. Furthermore, the introduction of 4,5-epoxy-1-cyclohexene improved the material's rigidity and heat resistance, while also introducing functionalized sites (double bonds), laying the foundation for post-functionalization modification.

[0061] Sample of Example 3 1 HNMR spectrum as follows Figure 6 As shown in the figure, the corresponding characteristic peaks are assigned to the corresponding peaks.

[0062] Example 4

[0063] The carbon dioxide-based random copolymer backbone (1 mmol, 23.7 g) synthesized in Example 1 was dissolved in anhydrous dichloromethane (polycarbonate concentration 0.4 mol / L). The primary amine polyether compound NH2-PEG-2000 (5 mmol, 10.0 g) was added to the solution, and the mixture was stirred at room temperature for 10 h. After the reaction was complete, the product was added to excess diethyl ether, precipitating the precipitate. This process was repeated twice. Finally, the mixture was placed in a vacuum oven and dried at 25 °C for 24 h to obtain a dried linear comb-shaped carbon dioxide copolymer containing hydrophilic branches. GPC testing showed that the polymer number-average molecular weight was 31.7 kg / mol, and the molecular weight distribution was 4.05. By introducing hydrophilic groups, especially hydrophilic branches, the hydrophilicity of the material was improved, broadening its applications in drug delivery, textiles, and biomedicine.

[0064] The GPC spectrum of the sample in Example 4 is as follows: Figure 2As shown, the GPC spectrum of this sample exhibits a single-peak distribution. Compared to Example 1, the molecular weight and molecular weight distribution of the grafted sample are improved. This indicates that the hydrophilic side chains were successfully grafted onto the polymer backbone. 1 HNMR spectrum as follows Figure 7 As shown in the figure, the corresponding characteristic peaks are assigned to the corresponding peaks.

[0065] Example 5

[0066] The carbon dioxide-based block copolymer backbone (1 mmol, 28.9 g) synthesized in Example 3 was dissolved in anhydrous dichloromethane (polycarbonate concentration 0.4 mol / L). The primary amine polyether compound NH2-PEG-2000 (5 mmol, 10.0 g) was added to the solution, and the mixture was stirred at room temperature for 10 h. After the reaction was complete, the product was added to excess diethyl ether, precipitating the precipitate. This process was repeated twice. Finally, the product was placed in a vacuum oven and dried at 25 °C for 24 h to obtain a dried linear comb-shaped carbon dioxide copolymer containing hydrophilic branches. GPC testing showed a polymer number-average molecular weight of 36.7 kg / mol and a molecular weight distribution of 3.86. By introducing hydrophilic groups, especially hydrophilic branches, the hydrophilicity of the material is improved, broadening its applications in drug delivery, textiles, and biomedicine.

[0067] The GPC spectrum of the sample in Example 5 is as follows: Figure 3 As shown, the GPC spectrum of this sample exhibits a single-peak distribution, and its molecular weight distribution is similar to that of the sample in Example 4. The sample's... 1 HNMR spectrum as follows Figure 8 As shown in the figure, the corresponding characteristic peaks are assigned to the corresponding peaks.

[0068] Table 1 shows the water contact angle data for samples from Examples 1-5. Figure 9 The diagram shows the water contact angles of samples from Examples 1-5. Samples from Examples 1-3 are polymers without grafted hydrophilic branches; the water contact angles of the three materials are similar, around 85°. Samples from Examples 4-5 are polymers grafted with hydrophilic branches; the hydrophilicity of the materials is significantly improved, and the water contact angle is reduced by more than 10°.

[0069] Table 1. Water contact angle data for samples from Examples 1-5

[0070] Material Example 1 Example 2 Example 3 Example 4 Example 5 Water contact angle (°) 85.5 84.5 84.5 71.5 71.0

[0071] 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 linear comb-shaped carbon dioxide copolymer containing a hydrophilic branch, characterized by, The polymer is linear comb structure, comprising carbon dioxide-based polymer main chain and polyether branch; the structural formula is as follows: In the formula: m is a natural number other than 0; n is a natural number other than 0; x is a natural number from 1 to 10; y is a natural number from 1 to 10; R1is selected from one of the following: R2is selected from one of the following: R3is selected from one of the following groups:

2. The linear comb-like carbon dioxide copolymer containing a hydrophilic branched chain according to claim 1, characterized by The polymer main chain is a copolymer prepared by taking epoxide 1, epoxide 2 and carbon dioxide as comonomers, and the polymer main chain comprises random and block structures; the polyether branch is prepared by grafting an amine-terminated polyether compound onto the polymer main chain through a post-functionalization reaction.

3. The linear comb-shaped carbon dioxide copolymer containing a hydrophilic branch according to claim 1, characterized by The copolymer has adjustable hydrophilic side chain grafting rate, and the grafting rate is 10-90 mol%; the number average molecular weight of the copolymer is 10.0-50.0 kg / mol; the glass transition temperature of the polymer can be adjusted in the range of 37-120 ℃, and the initial thermal decomposition temperature of the polymer can be adjusted in the range of 200-280 ℃.

4. A process for the preparation of a linear comb-shaped carbon dioxide copolymer containing hydrophilic branches as claimed in any one of claims 1 or 2, characterized in that, The linear comb carbon dioxide copolymer is prepared through two steps, the first step is to prepare a carbon dioxide-based ternary copolymer main chain with random or block structure, and the second step is to graft a hydrophilic side chain onto the polymer main chain through a post-functionalization reaction.

5. The preparation method according to claim 4, characterized in that, The preparation of the carbon dioxide-based ternary copolymer main chain with random or block structure comprises the following steps: under anhydrous and anaerobic conditions, epoxide 1 and epoxide 2 are added into a constant pressure feeding tank, a chain initiator and a catalyst are added into a high-pressure reaction kettle, then high-purity carbon dioxide gas is filled into the high-pressure reaction kettle, the epoxide in the constant pressure feeding tank is gradually added into the reaction kettle, and heating is performed for polymerization; after the reaction is completed, the polymer sample is cooled to room temperature, the pressure is released, trichloromethane is added into the reactor to completely dissolve the polymer, the obtained product is precipitated with anhydrous methanol, and then repeatedly dissolved and precipitated for multiple times, and vacuum drying is performed until the weight is constant, thereby obtaining a purified carbon dioxide-based ternary random copolymer main chain.

6. The preparation method according to claim 4, characterized in that, The preparation of the carbon dioxide-based ternary copolymer main chain with random or block structure comprises the following steps: under anhydrous and anaerobic conditions, epoxide 1 is added into a constant pressure feeding tank, a chain initiator and a catalyst are added into a high-pressure reaction kettle, then high-purity carbon dioxide gas is filled in, the epoxide in the constant pressure feeding tank is gradually added into the reaction kettle, and heating is performed for the first polymerization reaction, after a period of time, epoxide 2 is pumped into the reaction kettle by using a high-pressure injection pump to continue the second polymerization reaction, after the reaction is completed, the polymer sample is cooled to room temperature, the pressure is released, trichloromethane is added into the reactor to completely dissolve the polymer, the obtained product is precipitated with anhydrous methanol, and then repeatedly dissolved and precipitated for multiple times, and vacuum drying is performed until the weight is constant, thereby obtaining a purified carbon dioxide-based ternary block copolymer main chain.

7. The preparation method according to claim 4, characterized in that, The grafting of the hydrophilic side chain onto the polymer main chain through the post-functionalization reaction comprises the following steps: the prepared carbon dioxide-based ternary copolymer sample is dissolved in dry trichloromethane; a polyether containing primary amine groups at the chain end is added into the solution, and stirring is performed at room temperature for a period of time; after the reaction is completed, the product is added dropwise into excess ether, precipitates are separated, and the process is repeated twice; vacuum drying is performed until the weight is constant, thereby obtaining a purified linear comb carbon dioxide copolymer containing hydrophilic branches.

8. The method of making according to any one of claims 5 or 6, wherein, The epoxy compound 1 is an epoxy compound containing an unsaturated aliphatic ring structure, including any one of 4,5-epoxy-1-cyclohexene, 4,5-epoxy-3,6-dimethyl-1-cyclohexene, 4,5-epoxy-3,6-diethyl-1-cyclohexene, 4,5-epoxy-3,6-diisopropyl-1-cyclohexene, and the structure is as follows: The epoxide 2 is any one of: oxirane, propylene oxide, epichlorohydrin, butylene oxide, and has the structure: The molar ratio of the epoxy compound 1 to the epoxy compound 2 is 0.1-9:

1.

9. The preparation method according to claim 7, characterized in that, The hydrophilic branched chain molecule includes any one of methoxy polyethylene glycol-amino, methoxy polypropylene glycol-amino or methoxy polytetrahydrofuran-amino; the structure is as follows:

10. The method of making according to any one of claims 5 or 6, wherein, In the polymerization reaction, the catalyst is Zn3[Co(CN)6]2, the molar ratio of the catalyst to the epoxy compound is 1:200-20000; the chain initiator is any one of benzyl alcohol, ethylene glycol, propylene glycol, butanediol, polyethylene glycol 400, polypropylene glycol 600, the molar ratio of the chain initiator to the total amount of the epoxy monomer is 1:200-2000; the total amount of the epoxy monomer is the total amount of the epoxy compound 1 and the epoxy compound 2.

11. The method for preparing a carbon dioxide-based terpolymer backbone according to claim 5, characterized in that, The temperature of the polymerization reaction is 50-150℃, the time of the polymerization reaction is 4-12h, and the carbon dioxide pressure of the polymerization reaction is 0.5-3MPa.

12. The method of claim 7, wherein, The temperature of the post-functionalization reaction is 10-60℃, and the time of the post-functionalization reaction is 6-24h.

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