A high-permeability CO2 separation membrane, its preparation method and application

Abstract

This invention provides a high-permeability CO2 separation membrane, its preparation method, and its application. The raw materials for preparing the CO2 separation membrane include polypropylene carbonate and polybutylene adipate / terephthalate. Based on the total weight of the raw materials for preparing the CO2 separation membrane (100%), the content of polypropylene carbonate is 70-95 wt%, and the content of polybutylene adipate / terephthalate is 4-30 wt%. The separation membrane of this invention has a CO2 permeability coefficient of over 35000 Bar (25℃ / 0.1 MPa) and a CO2 / N2 selectivity of 10-20, making it suitable for high-flow-rate, low-concentration CO2 purification and separation.

Description

Technical Field

[0001] This invention belongs to the field of gas separation membrane technology, and relates to a high-permeability CO2 separation membrane, its preparation method, and its application. Background Technology

[0002] Membrane separation is one of the most promising CO2 recovery technologies. Commonly used membrane materials include polyimide, polysulfone, polysiloxane, polyethylene oxide, and polyether block amide. These materials have high selectivity for CO2 / N2, but due to the limitations of their structure, the CO2 permeability coefficient is generally between 1000 and 5000 Bar (25℃ / 0.1MPa). For the recovery of large flow rates and low concentrations of CO2 (such as CO2 capture in flue gas), the use of these membrane materials requires a large membrane area, which greatly increases the recovery cost. Therefore, there is an urgent need to develop a CO2 separation membrane with high permeability. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a high-permeability CO2 separation membrane, its preparation method, and its application. The separation membrane of the present invention has a CO2 permeability coefficient of up to 35,000 Bar (25℃ / 0.1MPa) and a CO2 / N2 selectivity of 10-20, making it suitable for high-flow-rate, low-concentration CO2 purification and separation.

[0004] To achieve this objective, the present invention adopts the following technical solution:

[0005] On one hand, the present invention provides a CO2 separation membrane with a high permeability coefficient. The raw materials for preparing the CO2 separation membrane include polypropylene carbonate (PPC) and polybutylene adipate / terephthalate (PBAT). Based on the total weight of the raw materials for preparing the CO2 separation membrane as 100%, the content of polypropylene carbonate is 70-95 wt%, and the content of polybutylene adipate / terephthalate is 4-30%.

[0006] In this invention, by selecting polypropylene carbonate and polybutylene adipate / terephthalate as important components of the separation membrane, the separation membrane can significantly improve the CO2 permeation coefficient and have high CO2 / N2 selectivity.

[0007] In this invention, PBAT can effectively improve the toughness of the separation membrane and has a similar processing temperature to PPC, so PBAT is chosen to be added. If PLA is chosen, wrinkles are easily generated on the membrane surface, affecting the appearance and use, while PHA and PBA are too expensive.

[0008] In this invention, the number-average molecular weight Mn of the polypropylene carbonate is 30,000 to 200,000 g / mol, for example, 30,000 g / mol, 50,000 g / mol, 80,000 g / mol, 100,000 g / mol, 120,000 g / mol, 150,000 g / mol, 180,000 g / mol or 200,000 g / mol, and the PDI (molecular weight distribution) is 2 to 6, for example, 2, 2.2, 2.5, 2.8, 3, 3.3, 3.5, 3.8, 4, 4.3, 4.5, 4.8, 5, 5.2, 5.5, 5.7 or 6, etc.

[0009] Preferably, the polypropylene carbonate has a propylene carbonate content of less than 2 wt%, for example, 2 wt%, 1.8 wt%, 1.5 wt%, 1.3 wt%, 1 wt%, 0.8 wt%, 0.5 wt%, 0.3 wt%, or 0.1 wt%.

[0010] Preferably, the glass transition temperature of the polypropylene carbonate is 24 to 36°C, for example, 24°C, 28°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, or 36°C.

[0011] Preferably, the polypropylene carbonate is obtained by reacting propylene oxide (PO) and CO2 in the presence of a catalyst. Preferably, the reaction temperature is 50–90°C (e.g., 50°C, 53°C, 55°C, 58°C, 60°C, 65°C, 70°C, 75°C, 80°C, 85°C, or 90°C), and the reaction time is 5–20 h (e.g., 5 h, 8 h, 10 h, 12 h, 15 h, 18 h, or 20 h). Preferably, the reaction is carried out at a pressure of 1.0–6.0 MPaG (e.g., 1.0 MPaG, 1.3 MPaG, 1.5 MPaG, 2 MPaG, 2.5 MPaG, 3 MPaG, 3.5 MPaG, 4 MPaG, 4.5 MPaG, 5 MPaG, 5.5 MPaG, or 6 MPaG).

[0012] Preferably, the catalyst includes, but is not limited to, any one or a combination of at least two of the following catalysts: zinc carboxylate, rare earth complex, alkyl zinc, bimetallic cyanide, metalloporphyrin, β-diimide, or Salen complex.

[0013] Preferably, the reaction is carried out in a solvent selected from polar aprotic solvents with low electron-donating ability, including but not limited to any one or a combination of at least two of PO (propylene oxide), supercritical CO2, dichloromethane, chloroform, acetone, toluene, or dimethyl sulfoxide.

[0014] Preferably, the poly(butylene adipate) terephthalate has a melt index of 3-5 g / 10 min at 190°C and 2.16 kg, for example, 3 g / 10 min, 3.5 g / 10 min, 3.8 g / 10 min, 4 g / 10 min, 4.5 g / 10 min, 4.8 g / 10 min or 5 g / 10 min.

[0015] Preferably, the terminal carboxyl group content of the poly(butylene adipate) / terephthalate does not exceed 25 mol / t, for example, 25 mol / t, 20 mol / t, 18 mol / t, 15 mol / t, 10 mol / t, 8 mol / t, 6 mol / t, 3 mol / t, 2 mol / t, etc.

[0016] Preferably, the water content of the poly(butylene adipate) / poly(terephthalate) does not exceed 500 ppm, for example, 500 ppm, 450 ppm, 400 ppm, 350 ppm, 300 ppm, 200 ppm, 100 ppm, 80 ppm, 50 ppm, 30 ppm, 20 ppm, 10 ppm, 5 ppm, etc.

[0017] In this invention, based on the total weight of the raw materials for preparing the CO2 separation membrane as 100%, the content of polypropylene carbonate is 70-95 wt%, for example, 70 wt%, 73 wt%, 75 wt%, 78 wt%, 80 wt%, 83 wt%, 85 wt%, 88 wt%, 90 wt%, 93 wt%, or 95 wt%, and the content of polybutylene adipate / terephthalate is 4-30%, for example, 4 wt%, 6 wt%, 8 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt%, or 30 wt%.

[0018] Preferably, the weight ratio of polypropylene carbonate to poly(butylene adipate / terephthalate) is 2.5–4:1, for example, 2.5:1, 2.8:1, 3:1, 3.3:1, 3.5:1, 3.8:1, or 4:1. In this invention, if the weight ratio of polypropylene carbonate to poly(butylene adipate / terephthalate) is less than 2.5:1, the selectivity of the separation membrane will decrease significantly; if the weight ratio is greater than 4:1, the membrane strength will decrease.

[0019] Preferably, the raw materials for preparing the CO2 separation membrane further include at least one of an optional compatibilizer, an optional antioxidant, or an optional anti-hydrolysis agent.

[0020] Preferably, the compatibilizer includes one or a combination of at least two of ADR-4468, ADR-4368, or ADR-4385.

[0021] Preferably, the antioxidant includes one or a combination of at least two of antioxidant-1010, antioxidant-1076, antioxidant-168, antioxidant-B215 or antioxidant-B245;

[0022] Preferably, the anti-hydrolysis agent includes one or a combination of at least two of Stabaxol I, Stabaxol P100, or Stabaxol P200.

[0023] Preferably, the raw materials for preparing the high-permeability CO2 separation membrane include the following components by weight percentage:

[0024] 70–95 wt% polypropylene carbonate (PPC), 4–30 wt% polybutylene adipate / terephthalate (PBAT), 0.1–2 wt% compatibilizer (e.g., 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.3 wt%, 1.5 wt%, 1.8 wt% or 2 wt%), 0.1–1.5 wt% (e.g., 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.8 wt%, 1 wt%, 1.3 wt% or 1.5 wt%) antioxidant, and 0.1–1 wt% (e.g., 0.1 wt%, 0.3 wt%, 0.5 wt%, 0.8 wt% or 1 wt%) anti-hydrolysis agent.

[0025] The thickness of the high-permeability CO2 separation membrane is 30–100 μm, for example, 30 μm, 40 μm, 50 μm, 60 μm, 70 μm, 80 μm, 90 μm, or 100 μm. If the CO2 separation membrane is too thin, its strength will be insufficient; if it is too thick, it will affect the permeation rate.

[0026] The high-permeability CO2 separation membrane can be prepared by methods such as coating, blow molding, and casting.

[0027] On the other hand, the present invention provides a method for preparing a high-permeability CO2 separation membrane as described above, the method comprising the following steps:

[0028] Polypropylene carbonate (PPC), polybutylene adipate / terephthalate (PBAT), optional compatibilizer, optional antioxidant, and optional anti-hydrolysis agent are dissolved in a solvent to obtain a solution. The solution is then coated to form a membrane to obtain the CO2 separation membrane with high permeability.

[0029] The method utilizes a coating method to prepare the CO2 separation membrane, wherein the concentration of the solution (referring to the total concentration of solute) is 5-15 wt%, for example, 5 wt%, 8 wt%, 10 wt%, 12 wt%, 14 wt%, or 15 wt%.

[0030] Preferably, the solvent is selected from any one or a combination of at least two of N,N-dimethylformamide (DMF), dichloromethane, acetone, toluene, or dimethyl sulfoxide.

[0031] On the other hand, the present invention provides another method for preparing a high-permeability CO2 separation membrane as described above, the preparation method comprising the following steps:

[0032] Polypropylene carbonate (PPC), polybutylene adipate / terephthalate (PBAT), optional compatibilizer, optional antioxidant and optional anti-hydrolysis agent are mixed, melt-extruded and granulated, and then blown into a membrane to obtain the CO2 separation membrane with high permeability coefficient.

[0033] The separation membrane is prepared by blow molding, and the processing temperature of melt extrusion is 135-170℃, for example 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃ or 170℃.

[0034] Preferably, the temperature of the blown film is 130-170°C, for example, 130°C, 135°C, 140°C, 145°C, 150°C, 155°C, 160°C, 165°C or 170°C.

[0035] On the other hand, the present invention provides another method for preparing a high-permeability CO2 separation membrane as described above, the preparation method comprising the following steps:

[0036] Polypropylene carbonate (PPC), polybutylene adipate / terephthalate (PBAT), optional compatibilizer, optional antioxidant and optional anti-hydrolysis agent are mixed, melt-extruded and granulated, and then cast or biaxially stretched to form a film to obtain the CO2 separation membrane with high permeability.

[0037] This method uses a casting method or a biaxial stretching process to prepare the separation membrane, wherein the melt extrusion processing temperature is 135-170℃, for example 135℃, 140℃, 145℃, 150℃, 155℃, 160℃, 165℃ or 170℃.

[0038] Preferably, the film casting is performed in a casting machine.

[0039] Preferably, the casting temperature is 150-180°C, for example 150°C, 155°C, 160°C, 165°C, 170°C, 175°C or 180°C.

[0040] On the other hand, the present invention provides the application of the high permeability CO2 separation membrane described above in CO2 capture and recovery.

[0041] In this invention, a high permeability coefficient refers to a CO2 permeability coefficient of 35,000 Bar or higher.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] This invention uses polypropylene carbonate (PPC) and polybutylene adipate (PBAT) as key components of the separation membrane. PPC contains a large number of carbonyl groups with an affinity for CO2, and as an amorphous polymer, it does not cause a decrease in CO2 permeability due to crystallization. The addition of PBAT enhances membrane toughness, increases permeability, and extends the membrane's lifespan. The separation membrane of this invention achieves a CO2 permeability of over 35,000 Bar (25°C / 0.1 MPa) and a CO2 / N2 selectivity of 10–20. With the same membrane area, this invention provides higher separation efficiency and is suitable for high-flow-rate, low-concentration CO2 purification and separation. Detailed Implementation

[0044] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0045] The preparation methods of the materials used in the following embodiments and comparative examples are as follows:

[0046] PPC preparation:

[0047] PPC-1 was prepared according to Example 10 in CN113185684A, with a number-average molecular weight of 95000 g / mol, a PDI of 3.6, a propylene carbonate content of 0.5 wt%, and a glass transition temperature of 31 °C.

[0048] The preparation of PPC-2 differs from that of PPC-1 in that the polymerization reaction time is adjusted from 12h to 4h, resulting in PPC-2 with a number-average molecular weight (Mn) of 25000 g / mol, a molecular weight distribution (PDI) of 5, a propylene carbonate content of 3.6 wt%, and a glass transition temperature of 23℃.

[0049] The preparation of PPC-3 differs from that of PPC-1 in that the polymerization reaction time is adjusted from 12h to 5h, resulting in PPC-3 with a number-average molecular weight (Mn) of 40000g / mol, a molecular weight distribution (PDI) of 3.8, a propylene carbonate content of 3.2wt%, and a glass transition temperature of 24℃.

[0050] Preparation of PPC-4: PPC-4 was obtained according to Example 7 of CN113185684A, with a number-average molecular weight Mn of 200000 g / mol, a molecular weight distribution PDI of 5.47, a propylene carbonate content of 0.4 wt%, and a glass transition temperature of 31 °C.

[0051] The preparation method of PBAT is as follows:

[0052] At 120°C, terephthalic acid, adipic acid, and butanediol in a molar ratio of 1:1:1.8 were dehydrated for 2 hours. Then, the temperature was raised to 150°C and melted. Tetraisopropyl titanate (0.2% of the total mass of terephthalic acid, adipic acid, and butanediol) was added as a catalyst. The first polymerization reaction was carried out at 130°C and atmospheric pressure for 2 hours. Then, the temperature was raised to 230°C at a rate of 30°C / h, and the second polymerization reaction was carried out at an absolute pressure of 50 kPa for 2 hours. Finally, the third polymerization reaction was carried out at 250°C and an absolute pressure of less than 500 Pa for 5 hours to obtain the biodegradable copolyester. The product had a melt index of 3.5 g / 10 min, 15 mol / t of terminal carboxyl groups, and 400 ppm of moisture.

[0053] The preparation method of PBS is as follows:

[0054] Succinic acid and 1,4-butanediol were mixed in a molar ratio of 0.9:1, and tetraisopropyl titanate (0.1% of the total mass of succinic acid and 1,4-butanediol) was added as a catalyst. The mixture was subjected to esterification at 180°C and atmospheric pressure for 3 hours. The temperature was then raised to 210°C and the vacuum was adjusted to 5 kPa. The reaction was continued for 3 hours to obtain a pre-condensation intermediate. The temperature was then raised to 250°C and the vacuum was increased to 100 kPa. The reaction was continued for 2 hours to obtain the product with a molecular weight of 80,000 g / mol, a PDI of 5, and a terminal carboxyl group of 20 mol / t.

[0055] The preparation method of polyvinyl carbonate is as follows:

[0056] CO2 and ethylene oxide were catalytically reacted in dichloromethane solvent at 75℃ and 0.6MPa for 15h to obtain the product with a molecular weight of 60000g / mol, a PDI of 4, and a Tg of 5℃.

[0057] In this invention, the molecular weight and molecular weight distribution are obtained by GPC testing, and the detection method refers to 5.10 of GB / T31124-2014.

[0058] The propylene carbonate content was obtained by NMR testing; Tg was tested according to 5.9 of GB / T 31124-2014.

[0059] The method for detecting terminal carboxyl groups refers to GB / T 14190-2017. The method for detecting melt index refers to GB / T 3682-2000, and the method for detecting moisture refers to 5.15 in GB / T 31124-2014.

[0060] In this invention, the testing standards for membrane permeability coefficient and selectivity are based on GB / T 1038.1-2022.

[0061] Example 1

[0062] 12g PPC-1, 3g PBAT, 0.05g compatibilizer ADR-4468, 0.08g antioxidant-168, and 0.08g anti-hydrolysis agent Stabaxol P200 were added to 95g DMF and stirred at 80℃ for 0.5h. The mixture was then heated to 140℃ and stirred for another 0.5h to obtain a homogeneous solution. After standing for 0.5h to remove bubbles, the degassed solution was poured onto a horizontal glass plate and spread evenly. The solvent was evaporated to obtain a nascent membrane. The nascent membrane was then vacuum dried at 160℃ for 20min to remove residual DMF, resulting in a 30μm thick CO2 separation membrane. The membrane's permeability and selectivity were tested. The CO2 separation membrane (25℃ / 0.1MPa) had a CO2 permeability of 35880 Bar, a CO2 / N2 selectivity of 13.6, and a tensile strength of 49MPa.

[0063] Example 2

[0064] 75 parts of PPC-1, 25 parts of PBAT, 0.3 parts of compatibilizer ADR-4468, 0.5 parts of antioxidant-168 and 0.5 parts of hydrolysis resistant agent Stabaxol P200 were blended and granulated in a twin-screw extruder at a processing temperature of 155℃ (±5℃).

[0065] The blended modified particles were blown into a film in a blown film machine at a blowing temperature of 160℃ (±5℃) and a film thickness of 30μm to obtain a CO2 separation membrane with a CO2 permeability coefficient of 45850Bar, a CO2 / N2 selectivity of 10.5, and a tensile strength of 40MPa.

[0066] Example 3

[0067] 80 parts of PPC-1, 20 parts of PBAT, 0.3 parts of compatibilizer ADR-4468, 0.5 parts of antioxidant-168 and 0.5 parts of hydrolysis resistant agent Stabaxol P200 were blended and granulated in a twin-screw extruder at a processing temperature of 155℃ (±5℃).

[0068] The blended modified particles were blown into a film in a blown film machine at a blowing temperature of 160℃ (±5℃) and a film thickness of 30μm to obtain a CO2 separation membrane with a CO2 permeability coefficient of 38680 Bar, a CO2 / N2 selectivity of 11.2, and a tensile strength of 38MPa.

[0069] Example 4

[0070] 75 parts of PPC-1, 25 parts of PBAT, 0.3 parts of compatibilizer ADR-4468, 0.5 parts of antioxidant-168 and 0.5 parts of hydrolysis resistant agent were blended and granulated in a twin-screw extruder at a processing temperature of 155℃ (±5℃).

[0071] The blended modified particles were cast into a film at a casting temperature of 170℃ (±5℃) and a film thickness of 30μm to obtain a CO2 separation membrane with a CO2 permeability coefficient of 40120 Bar, a CO2 / N2 selectivity of 10.4, and a tensile strength of 43MPa.

[0072] Example 5

[0073] 90 parts of PPC-1, 10 parts of PBAT, 0.3 parts of compatibilizer ADR-4468, 0.5 parts of antioxidant-168 and 0.5 parts of hydrolysis resistant agent were blended and granulated in a twin-screw extruder at a processing temperature of 145℃ (±5℃).

[0074] The blended modified particles were cast into a film at a casting temperature of 160℃ (±5℃) and a film thickness of 30μm to obtain a CO2 separation membrane with a CO2 permeability coefficient of 30250Bar, a CO2 / N2 selectivity of 14.6, and a tensile strength of 29MPa.

[0075] Example 6

[0076] 12g PPC-1, 4.6g PBAT, 0.05g compatibilizer ADR-4468, 0.08g antioxidant-168, and 0.08g anti-hydrolysis agent Stabaxol P200 were added to 95g DMF and stirred at 80℃ for 0.5h. The mixture was then heated to 140℃ and stirred for another 0.5h to obtain a homogeneous solution. After standing for 0.5h to remove bubbles, the degassed solution was poured onto a horizontal glass plate and spread evenly. The solvent was evaporated to obtain a nascent membrane. The nascent membrane was then vacuum dried at 160℃ for 20min to remove residual DMF, resulting in a 30μm thick CO2 separation membrane. The membrane permeability and selectivity were tested. The CO2 separation membrane (25℃ / 0.1MPa) had a CO2 permeability of 36100 Bar, a CO2 / N2 selectivity of 13.6, and a tensile strength of 41MPa.

[0077] Example 7

[0078] The only difference from Example 1 is that PPC-1 is replaced with PPC-2, which has a number-average molecular weight Mn of 25000 g / mol and a molecular weight distribution PDI of 5. All other aspects are the same as in Example 1.

[0079] The membrane's permeability and selectivity were tested. The CO2 separation membrane (25℃ / 0.1MPa) had a CO2 permeability of 80530 Bar, a CO2 / N2 selectivity of 5.6, and a tensile strength of 23MPa.

[0080] Example 8

[0081] The only difference from Example 2 is that the amounts of PPC-1 and PBAT used are 70g PPC-1 and 30g PBAT, respectively.

[0082] The membrane's permeability and selectivity were tested. The CO2 separation membrane (25℃ / 0.1MPa) had a CO2 permeability of 46200 Bar, a CO2 / N2 selectivity of 8.6, and a tensile strength of 40MPa.

[0083] Example 9

[0084] The only difference from Example 1 is that the amounts of PPC-1 and PBAT used are 12.5g PPC-1 and 2.5g PBAT, respectively.

[0085] The membrane's permeability and selectivity were tested. The CO2 separation membrane (25℃ / 0.1MPa) had a CO2 permeability of 32300 Bar, a CO2 / N2 selectivity of 11.8, and a tensile strength of 34MPa.

[0086] Example 10

[0087] 75 parts of PPC-3, 25 parts of PBAT, 0.3 parts of compatibilizer ADR-4468, 0.5 parts of antioxidant-168 and 0.5 parts of hydrolysis resistant agent Stabaxol P200 were blended and granulated in a twin-screw extruder at a processing temperature of 160℃ (±5℃).

[0088] The blended modified particles were blown into a film in a blown film machine at a blowing temperature of 165℃ (±5℃) and a film thickness of 30μm to obtain a CO2 separation membrane with a CO2 permeability coefficient of 47580 Bar, a CO2 / N2 selectivity of 10.2, and a tensile strength of 37MPa.

[0089] Example 11

[0090] 12g PPC-4, 3g PBAT, 0.05g compatibilizer ADR-4468, 0.08g antioxidant-168, and 0.08g anti-hydrolysis agent Stabaxol P200 were added to 95g DMF and stirred at 80℃ for 0.5h. The mixture was then heated to 140℃ and stirred for another 0.5h to obtain a homogeneous solution. After standing for 0.5h to remove bubbles, the degassed solution was poured onto a horizontal glass plate and spread evenly. The solvent was evaporated to obtain a nascent membrane. The nascent membrane was then vacuum dried at 160℃ for 20min to remove residual DMF, resulting in a 30μm thick CO2 separation membrane. The CO2 separation membrane (25℃ / 0.1MPa) had a CO2 permeability coefficient of 32200 Bar, a CO2 / N2 selectivity of 17.6, and a tensile strength of 53MPa.

[0091] Comparative Example 1

[0092] When pure PPC-1 particles were blown into film in a blown film machine, it was found that pure PPC was difficult to blow into film, and the film was brittle and easy to break. Similar problems also existed when other methods were used.

[0093] Comparative Example 2

[0094] The only difference from Example 1 is that PPC-1 is replaced with an equal amount of PBS (homemade).

[0095] The membrane's permeability and selectivity were tested. The CO2 separation membrane (25℃ / 0.1MPa) had a CO2 permeability of 12350 Bar, a CO2 / N2 selectivity of 12, and a tensile strength of 26MPa.

[0096] Comparative Example 3

[0097] The only difference from Example 1 is that PPC-1 is replaced with an equal amount of polyvinyl carbonate (as described above).

[0098] The membrane's permeability and selectivity were tested. The CO2 separation membrane (25℃ / 0.1MPa) had a CO2 permeability of 15320 Bar, a CO2 / N2 selectivity of 14, and a tensile strength of 22MPa.

[0099] Comparative Example 4

[0100] The only difference from Example 2 is that the amount of PPC and PBAT used is 60 parts PPC and 40 parts PBAT, respectively.

[0101] The membrane's permeability and selectivity were tested. The CO2 separation membrane (25℃ / 0.1MPa) had a CO2 permeability of 65850 Bar, a CO2 / N2 selectivity of 6.8, and a tensile strength of 42MPa.

[0102] Example 7 illustrates that when the molecular weight is below 30,000 g / mol, the separation membrane is difficult to form, and even if it is formed, the strength is significantly weak. Example 8 illustrates that a PPC to PBAT mass ratio of 2.3:1 significantly reduces the selectivity of the separation membrane. Example 9 illustrates that a PPC to PBAT mass ratio of 5:1 reduces the membrane strength.

[0103] Both PBS and polyvinyl carbonate used in Comparative Examples 2 and 3 exhibited crystallization, which inhibited the carbon dioxide permeation rate. In addition, polyvinyl carbonate also had problems such as insufficient strength.

[0104] In Comparative Example 4, the PPC content was less than 70%, resulting in a significant decrease in separation selectivity.

[0105] The applicant declares that this invention illustrates the high-permeability CO2 separation membrane, its preparation method, and its application through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A CO2 separation membrane with a high permeability coefficient, characterized in that, The raw materials for preparing the CO2 separation membrane include polypropylene carbonate and polybutylene adipate / terephthalate. Based on the total weight of the raw materials for preparing the CO2 separation membrane as 100%, the content of polypropylene carbonate is 70~95wt%, and the content of polybutylene adipate / terephthalate is 4~30wt%. The components of the prepared CO2 separation membrane include polypropylene carbonate and polybutylene adipate / terephthalate.

2. The high-permeability CO2 separation membrane according to claim 1, characterized in that, The number-average molecular weight (Mn) of the polypropylene carbonate is 30,000 to 200,000 g / mol.

3. The high-permeability CO2 separation membrane according to claim 1, characterized in that, The molecular weight distribution (PDI) of the polypropylene carbonate is 2-6.

4. The high-permeability CO2 separation membrane according to claim 1, characterized in that, The polypropylene carbonate contains less than 2 wt% propylene carbonate.

5. The high-permeability CO2 separation membrane according to claim 1, characterized in that, The glass transition temperature of the polypropylene carbonate is 24~36℃.

6. The high-permeability CO2 separation membrane according to claim 1, characterized in that, The poly(butylene adipate) / terephthalate has a melt index of 3~5 g / 10 min at 190℃ and 2.16 kg.

7. The high-permeability CO2 separation membrane according to claim 1, characterized in that, The end carboxyl group content of the poly(adipic acid / butyl terephthalate) does not exceed 25 mol / t.

8. The high-permeability CO2 separation membrane according to claim 1, characterized in that, The water content of the poly(butylene adipate / terephthalate) does not exceed 500 ppm.

9. The high-permeability CO2 separation membrane according to claim 1, characterized in that, The weight ratio of polypropylene carbonate to poly(butylene adipate / terephthalate) is 2.5 to 4:

1.

10. The high-permeability CO2 separation membrane according to claim 1, characterized in that, The raw materials for preparing the CO2 separation membrane also include at least one of a compatibilizer, an antioxidant, or an anti-hydrolysis agent.

11. The high-permeability CO2 separation membrane according to claim 10, characterized in that, The compatibilizer includes one or a combination of at least two of ADR-4468, ADR-4368, or ADR-4385.

12. The high-permeability CO2 separation membrane according to claim 10, characterized in that, The antioxidants include one or a combination of at least two of antioxidant-1010, antioxidant-1076, antioxidant-168, antioxidant-B215, or antioxidant-B245.

13. The high-permeability CO2 separation membrane according to claim 10, characterized in that, The anti-hydrolysis agent includes one or a combination of at least two of Stabaxol I, Stabaxol P100, or Stabaxol P200.

14. The high-permeability CO2 separation membrane according to claim 1, characterized in that, The raw materials for preparing the high-permeability CO2 separation membrane include the following components by weight percentage: 70-95 wt% polypropylene carbonate, 4-30 wt% polybutylene adipate / terephthalate, 0.1-2 wt% compatibilizer, 0.1-1.5 wt% antioxidant, and 0.1-1 wt% hydrolysis inhibitor.

15. The high-permeability CO2 separation membrane according to any one of claims 1 to 14, characterized in that, The thickness of the high-permeability CO2 separation membrane is 30~100μm.

16. The method for preparing a high-permeability CO2 separation membrane according to any one of claims 1 to 15, characterized in that, The preparation method includes the following steps: Polypropylene carbonate, polybutylene adipate / terephthalate, optional compatibilizer, optional antioxidant, and optional anti-hydrolysis agent are dissolved in a solvent to obtain a solution. The solution is then coated to form a membrane to obtain the CO2 separation membrane with high permeability.

17. The preparation method according to claim 16, characterized in that, The concentration of the solution is 5-15 wt%.

18. The preparation method according to claim 16, characterized in that, The solvent is selected from any one or a combination of at least two of N,N-dimethylformamide, dichloromethane, acetone, toluene, or dimethyl sulfoxide.

19. The method for preparing a high-permeability CO2 separation membrane according to any one of claims 1 to 15, characterized in that, The preparation method includes the following steps: Polypropylene carbonate, polybutylene adipate / terephthalate, optional compatibilizer, optional antioxidant and optional anti-hydrolysis agent are mixed, melt-extruded and granulated, and then blown into a membrane to obtain the CO2 separation membrane with high permeability.

20. The preparation method according to claim 19, characterized in that, The processing temperature for melt extrusion is 135~170℃.

21. The preparation method according to claim 19, characterized in that, The temperature of the blown film is 130~170℃.

22. The method for preparing a high-permeability CO2 separation membrane according to any one of claims 1 to 15, characterized in that, The preparation method includes the following steps: Polypropylene carbonate, polybutylene adipate / terephthalate, optional compatibilizer, optional antioxidant and optional anti-hydrolysis agent are mixed, melt-extruded and granulated, and then cast or stretched into a film to obtain the CO2 separation membrane with high permeability.

23. The preparation method according to claim 22, characterized in that, The processing temperature for melt extrusion is 135~170℃.

24. The preparation method according to claim 22, characterized in that, The film casting process is carried out in a casting machine.

25. The preparation method according to claim 22, characterized in that, The casting temperature is 150~180℃.

26. The application of the high-permeability CO2 separation membrane according to any one of claims 1 to 15 in CO2 capture and recovery.