Semi-bio-based polyamide containing cross-linked structure as well as preparation method and application of semi-bio-based polyamide

Abstract

The invention relates to semi-bio-based polyamide containing a cross-linked structure as well as a preparation method and application of the semi-bio-based polyamide, and belongs to the technical field of polyamide preparation. The semi-bio-based polyamide containing the cross-linked structure contains a structure shown in a formula (I), 2, 5-furandicarboxylic acid taken from a bio-based material, a derivative monomer of the 2, 5-furandicarboxylic acid and aromatic diamine are used as raw materials for polycondensation, and aromatic triamine is used as a cross-linking agent. The semi-bio-based polyamide with the cross-linked structure provided by the invention has excellent thermal stability, excellent mechanical property, excellent wettability to electrolyte and outstanding chemical stability and electrochemical stability, can be applied to a lithium ion battery diaphragm, and can be used as a lithium ion battery diaphragm coating material with excellent performance and durability. The performance of the diaphragm is further improved, so that the battery capacity, the cycle and rate discharge performance, the safety and the like are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of polyamide preparation, and in particular relates to a semi-biobased polyamide containing a cross-linked structure and a preparation method and application thereof. Background Art

[0002] Lithium-ion battery is a sustainable energy storage system that can realize the mutual conversion of electrical energy and chemical energy. It has the advantages of high energy density and specific energy, high working voltage, long storage and cycle life, no memory effect, low self-discharge rate, safety and pollution-free. These advantages fully meet the urgent requirements for lightweight and miniaturized power supply for electrical appliances in its application. Nowadays, lithium-ion batteries have been widely used in various fields, such as various electronic appliances and electric vehicles.

[0003] Lithium-ion batteries are mainly composed of positive electrodes, negative electrodes, electrolytes and diaphragms. The diaphragm is an important component, and its main function is to separate the positive and negative electrodes of the battery to prevent the two electrodes from directly contacting and short-circuiting. In addition, it also has the function of allowing ions to pass freely. The performance of the diaphragm material determines the interface structure and internal resistance of the battery, thereby affecting the battery capacity, cycle and rate discharge performance, and safety. Polyamide is a commonly used diaphragm material. For example, the preparation method of a water-based coated diaphragm with high wettability of the electrolyte disclosed in Publication (Announcement) No. CN116315425A adds modified bio-based polyamide particles to reduce the contact angle with the electrolyte, greatly improving the wettability of the electrolyte; for example, the preparation method of a nano-scale bio-based semi-aromatic polyamide particle disclosed in Publication (Announcement) No. CN116162266A can be used in any coating with a water-based solvent system to effectively improve the heat resistance and membrane rupture temperature of the coated product.

[0004] However, the polyamide prepared by the existing polyamide preparation method still has certain problems in its dimensional stability, thermal stability, mechanical properties, wettability to electrolyte, chemical stability and electrochemical stability, and there is much room for improvement. Summary of the invention

[0005] The purpose of the present invention is to provide a semi-biobased polyamide containing a cross-linked structure and a preparation method and application thereof in order to solve the above problems.

[0006] The present invention achieves the above-mentioned purpose through the following technical solutions:

[0007] The first object of the present invention is to provide a semi-biobased polyamide containing a cross-linked structure, wherein the semi-biobased polyamide containing a cross-linked structure has the structure of the following formula (I):

[0008]

[0009] In formula (I), m>1, k>1 and m:k=(20-100):1, m+k=500-2000;

[0010] Ar1 is a residue of a divalent aromatic amine, Ar2 is a residue of a trivalent aromatic amine, and R is a linear polymer chain cross-linked by the trivalent aromatic amine.

[0011] The second object of the present invention is to provide a method for preparing the above-mentioned semi-biobased polyamide containing a cross-linked structure, comprising the following steps:

[0012] (1) mixing a diamine monomer with a first organic solvent under an inert gas atmosphere to obtain a diamine solution;

[0013] (2) taking 2,5-furandicarboxylic acid or a derivative monomer thereof, adding part of the 2,5-furandicarboxylic acid or a derivative monomer thereof to the diamine solution, reacting at a first predetermined temperature, then adding a triamine monomer, and heating to a second predetermined temperature to obtain a polyamide prepolymer solution;

[0014] (3) adding another portion of the 2,5-furandicarboxylic acid or its derivative monomer into the polyamide prepolymer solution, and then heating the solution to a third predetermined temperature to obtain a semi-biobased polyamide solution containing a cross-linked structure and having a desired apparent viscosity;

[0015] (4) mixing the semi-bio-based polyamide solution with a second organic solvent, and then adding water to obtain semi-bio-based polyamide, and then pulping, washing, filtering, and drying the semi-bio-based polyamide to obtain semi-bio-based polyamide particles containing a cross-linked structure.

[0016] As a further optimization scheme of the present invention, in step (1), the inert gas includes one or more of nitrogen, helium and argon.

[0017] In step (1), the diamine monomer includes one or more of m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenylmethane.

[0018] In step (1), the mass ratio of the diamine monomer to the first organic solvent is 1:(5-10).

[0019] As a further optimization scheme of the present invention, in step (1), after the diamine monomer is mixed with the first organic solvent, the process further comprises: heating to 60-80° C. to dissolve the diamine monomer, and then cooling to 0-10° C. to obtain the diamine solution.

[0020] As a further optimization scheme of the present invention, in step (2), the derivative monomer of 2,5-furandicarboxylic acid is 2,5-furandicarboxylic acid chloride.

[0021] In step (2), the triamine monomer includes one or more of 1,3,5-triaminobenzene, 1,1'-biphenyl-3,3',5,5'-tetramine and 3,3',5,5'-tetraaminodiphenylmethane.

[0022] As a further optimization scheme of the present invention, in step (2), the mass ratio of the part of 2,5-furandicarboxylic acid or its derivative monomer to the 2,5-furandicarboxylic acid or its derivative monomer is 95-99%.

[0023] In step (2), the first predetermined temperature is no greater than 15°C.

[0024] In step (2), the second predetermined temperature is 20-25°C.

[0025] The molar ratio of the 2,5-furandicarboxylic acid or its derivative monomer to the diamine monomer is 1:(0.8-1).

[0026] The molar ratio of the triamine monomer to the diamine monomer is (0.01-0.05):1.

[0027] As a further optimization solution of the present invention, in step (3), the third predetermined temperature is 60-70°C.

[0028] In step (3), the expected apparent viscosity is 10000-70000 mPa·s. Specifically, during the temperature rise reaction, 2,5-furandicarboxylic acid or its derivative monomer is added according to the actual apparent viscosity until a cross-linked structure semi-bio-based polyamide solution with the expected apparent viscosity is obtained. The added 2,5-furandicarboxylic acid or its derivative monomer is 0.1%-1% of the mass of the 2,5-furandicarboxylic acid or its derivative monomer taken in step (2).

[0029] In step (4), the mass of the semi-bio-based polyamide solution is 3-10 times the mass of the second organic solvent; and the mass of the water is 8-10 times the mass of the semi-bio-based polyamide solution.

[0030] The first organic solvent and the second organic solvent independently include at least one of N,N-dimethylacetamide, N-methylpyrrolidone and N,N-dimethylformamide.

[0031] The third object of the present invention is to provide a lithium-ion battery separator. The raw material components of the separator include 0.8-1.5 parts of a third organic solvent, 0.01-0.5 parts of ceramic particles, 0.01-0.5 parts of the semi-biobased polyamide prepared above, and 0.01-0.2 parts of polyvinylidene fluoride, by weight.

[0032] The fourth object of the present invention is to provide a method for preparing the above-mentioned lithium ion battery separator, comprising the following steps:

[0033] (1) mixing a third organic solvent, ceramic particles, semi-bio-based polyamide and polyvinylidene fluoride to obtain a semi-bio-based coating slurry;

[0034] (2) The semi-bio-based coating slurry is coated on at least one side of a lithium-ion battery base membrane, and then subjected to mixed solvent extraction, water extraction, and drying to obtain a semi-bio-based polyamide separator containing a cross-linked structure.

[0035] As a further optimization scheme of the present invention, the mixed solvent includes a fourth organic solvent and water, and the volume ratio of the fourth organic solvent to water is (0.1-2):1; the third organic solvent and the fourth organic solvent independently include at least one of N,N-dimethylacetamide, N-methylpyrrolidone and N,N-dimethylformamide.

[0036] The beneficial effects of the present invention are:

[0037] (1) The coated diaphragm prepared using the above-mentioned semi-bio-based polyamide material containing a cross-linked structure has a high porosity and electrolyte absorption rate, and an average tensile strength of 13.08 MPa, which can meet the requirements of the battery assembly process for the mechanical properties of the diaphragm; at the same time, the shrinkage rate is less than 2% at 150°C, and it has excellent thermal stability, ensuring the high safety of the battery under conditions such as high temperature or thermal runaway.

[0038] (2) Semi-biobased polyamide materials with cross-linked structures have good pore structure and low swelling characteristics, thus having excellent electrochemical stability. They can be prepared as lithium-ion battery separator coating materials and applied to lithium-ion batteries, which will improve battery capacity, cycle and rate discharge performance, and safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 This is the DSC curve of the semi-biobased polyamide diaphragm containing a cross-linked structure prepared in Example 4 under a nitrogen atmosphere;

[0040] Figure 2 This is an electron micrograph of the semi-biobased polyamide diaphragm with a cross-linked structure prepared in Example 3, and (b) is a partial enlarged view of (a);

[0041] Figure 3 This is an electron micrograph of the semi-bio-based polyamide diaphragm with a cross-linked structure prepared in Example 4, and (b) is a partial enlarged view of (a). DETAILED DESCRIPTION

[0042] The embodiments of the present invention are described in detail below, which are intended to explain the present invention but should not be construed as limiting the present invention.

[0043] In the first aspect of the present invention, the present invention provides a semi-biobased polyamide containing a cross-linked structure having the structure of the following formula (I):

[0044]

[0045] In formula (I), m>1, k>1 and m:k=(20-100):1, m+k=500-2000;

[0046] Ar1 is a residue of a divalent aromatic amine, Ar2 is a residue of a trivalent aromatic amine, and R is a linear polymer chain cross-linked by the trivalent aromatic amine.

[0047] By integrating the residues of dibasic aromatic amines, tribasic aromatic amines and linear polymer chains cross-linked by tribasic aromatic amines into semi-bio-based polyamide, the semi-bio-based polyamide has a three-dimensional network structure, thereby improving the thermal stability, solvent resistance and mechanical properties of the polyamide molecules. Coating it on the lithium battery separator can improve the performance of the separator.

[0048] In the second aspect of the present invention, the present invention proposes a method for preparing a semi-biobased polyamide material containing a cross-linked structure, which is achieved by the following technical scheme:

[0049] (1) Under an inert gas atmosphere, a diamine monomer is mixed with a first organic solvent to obtain a diamine solution.

[0050] Furthermore, the mass ratio of the diamine monomer to the first organic solvent is 1:(5-10). Thus, the diamine monomer is dissolved more fully.

[0051] Furthermore, after the diamine monomer is mixed with the first organic solvent, the process further includes: heating to 60-80° C. to dissolve the diamine monomer, and then cooling to 0-10° C. to obtain a diamine solution. Thus, the obtained diamine solution is more stable and uniform, which is helpful for subsequent polymerization reactions.

[0052] It should be noted that the inert gas includes one or more of nitrogen, helium and argon; the diamine monomer includes one or more of m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether and 4,4'-diaminodiphenylmethane.

[0053] (2) taking 2,5-furandicarboxylic acid or a derivative monomer thereof, adding part of the 2,5-furandicarboxylic acid or a derivative monomer thereof into a diamine solution, reacting at a first predetermined temperature, then adding a triamine monomer, and heating to a second predetermined temperature to obtain a polyamide prepolymer solution.

[0054] Further, the mass ratio of the part of 2,5-furandicarboxylic acid or its derivative monomer to 2,5-furandicarboxylic acid or its derivative monomer is 95-99%; the first predetermined temperature is not more than 15°C; and the second predetermined temperature is 20-25°C.

[0055] Furthermore, the molar ratio of 2,5-furandicarboxylic acid or its derivative monomer to the diamine monomer is 1:(0.8-1); the molar ratio of the triamine monomer to the diamine monomer is (0.01-0.05):1.

[0056] It should be noted that the derivative monomer of 2,5-furandicarboxylic acid is 2,5-furandicarboxylic acid chloride; the triamine monomer includes one or more of 1,3,5-triaminobenzene, 1,1'-biphenyl-3,3',5,5'-tetramine and 3,3',5,5'-tetraaminodiphenylmethane.

[0057] (3) adding another portion of 2,5-furandicarboxylic acid or a monomer derived from it into the polyamide prepolymer solution, and then heating the solution to a third predetermined temperature to obtain a semi-biobased polyamide solution containing a cross-linked structure and having a desired apparent viscosity.

[0058] Further, the third predetermined temperature is 60-70°C;

[0059] Furthermore, the expected apparent viscosity is 10000-70000 mPa·s, and during the temperature rise reaction, 2,5-furandicarboxylic acid or its derivative monomer is added according to the actual apparent viscosity until a cross-linked structure semi-bio-based polyamide solution with the expected apparent viscosity is obtained. The added 2,5-furandicarboxylic acid or its derivative monomer is 0.1%-1% of the mass of the 2,5-furandicarboxylic acid or its derivative monomer taken in step (2).

[0060] By adding 2,5-furandicarboxylic acid or its derivative monomers in batches for multiple times, the polymerization reaction can be made more complete, which is more conducive to obtaining a semi-bio-based polyamide solution with a desired viscosity and molecular weight.

[0061] (4) mixing the semi-bio-based polyamide solution with a second organic solvent, and then adding water to obtain semi-bio-based polyamide, and then pulping, washing, filtering, and drying the semi-bio-based polyamide to obtain semi-bio-based polyamide particles containing a cross-linked structure.

[0062] Further, the mass of the semi-bio-based polyamide solution is 3-10 times the mass of the second organic solvent; the mass of water is 8-10 times the mass of the semi-bio-based polyamide solution;

[0063] It should be noted that the first organic solvent and the second organic solvent independently include at least one of N,N-dimethylacetamide, N-methylpyrrolidone and N,N-dimethylformamide.

[0064] By polymerizing diamine with 2,5-furandicarboxylic acid or its derivative monomers and adding triamine during the polymerization process, the performance of the final semi-biobased polyamide particles can be improved. During the polymerization reaction, the selection of the crosslinking agent, the amount of the crosslinking agent, the time of adding the crosslinking agent, etc. are all crucial. If it cannot be precisely controlled, low crosslinking density will lead to the failure to form a crosslinked structure, and high crosslinking density will cause the viscosity and molecular weight of the polymer to surge, making it impossible to obtain a suitable product.

[0065] In the third aspect of the present invention, the present invention provides a lithium-ion battery separator. The raw material components of the separator include 0.8-1.5 parts of a third organic solvent, 0.01-0.5 parts of ceramic particles, 0.01-0.5 parts of the semi-biobased polyamide prepared above, and 0.01-0.2 parts of polyvinylidene fluoride, by weight.

[0066] In a fourth aspect of the present invention, the present invention provides a method for preparing a lithium ion battery separator, comprising the following steps:

[0067] (1) mixing a third organic solvent, ceramic particles, semi-bio-based polyamide and polyvinylidene fluoride to obtain a semi-bio-based coating slurry;

[0068] (2) The semi-bio-based coating slurry is coated on at least one side of a lithium-ion battery base membrane, and then subjected to mixed solvent extraction, water extraction, and drying to obtain a semi-bio-based polyamide separator containing a cross-linked structure.

[0069] Further, the mixed solvent includes a fourth organic solvent and water, the volume ratio of the fourth organic solvent to water is (0.1-2):1; the third organic solvent and the fourth organic solvent independently include at least one of N,N-dimethylacetamide, N-methylpyrrolidone and N,N-dimethylformamide. The drying temperature is set to 60-150°C.

[0070] The present invention is further explained below by specific examples. The methods used in the present invention are conventional methods known to those skilled in the art unless otherwise specified, and the reagents and other materials used are commercially available products unless otherwise specified.

[0071] Example 1

[0072] Heat the 100L reactor to 80℃ to completely dry the water, and use argon to replace the air in the reactor, which takes 2h. After completion, add 46.825kg of N,N-dimethylacetamide and 6.284kg of 4,4'-diaminodiphenyl ether into the reactor under the protection of argon, heat and stir to completely dissolve them; after dissolution, cool to 0℃ to obtain a clear diamine solution. Take 5kg of 2,5-furandicarboxylic acid, first add 4.9g of 2,5-furandicarboxylic acid chloride to the reactor, control the addition rate to keep the temperature below 15℃, then quickly add 0.05kg of 1,3,5-triaminobenzene, and heat to 20-25℃ and stir for 2h to obtain a polyamide prepolymer solution. The remaining 0.1g of 2,5-furandicarboxylic acid was added to the polyamide prepolymer solution, and the temperature was raised to 60-70°C for reaction for 6h. During this period, 0.025kg of 2,5-furandicarboxylic acid was added according to the apparent viscosity until a semi-bio-based polyamide solution with a cross-linked structure and a viscosity of 43400mPa·s was obtained. Then, 200kg of N,N-dimethylacetamide was added to the semi-bio-based polyamide solution, and then 400kg of water was added thereto to stir and precipitate the semi-bio-based polyamide, and then the semi-bio-based polyamide particles with a cross-linked structure were obtained after pulping, washing, filtration and drying.

[0073] Into a stirring tank, 81.2 kg of N,N-dimethylacetamide, 10.3 kg of ceramic particles, 5.4 kg of the semi-bio-based polyamide prepared above, and 1.8 kg of polyvinylidene fluoride were added in sequence, and stirred for 2 hours to obtain a coating slurry; the coating slurry was applied to both sides of the lithium-ion battery base membrane, and after solvent extraction, water extraction, and drying at 75°C, a semi-bio-based polyamide membrane diaphragm with a cross-linked structure was prepared.

[0074] Example 2

[0075] Heat the 50L reactor to 80°C to completely dry the water, and use nitrogen to replace the air in the reactor for 2 hours. After completion, add 23.41kg of N,N-dimethylacetamide and 2.52kg of 4,4'-diaminodiphenyl ether to the reactor under the protection of argon, heat and stir to completely dissolve; after dissolution, cool to 0°C to obtain a clear diamine solution. Take 2.5kg of 2,5-furandicarboxylic acid chloride, first add 2.425g of 2,5-furandicarboxylic acid chloride to the reactor, control the addition rate to keep the temperature below 15°C, then quickly add 0.055kg of 1,1'-biphenyl-3,3',5,5'-tetramine, and heat to 20-25°C and stir for 2h to obtain a polyamide prepolymer solution. Then, the remaining 2,5-furandicarboxylic acid chloride is added to the polyamide prepolymer solution, and the temperature is raised to 60-70°C for reaction for 6 hours. During this period, 0.025 kg of 2,5-furandicarboxylic acid chloride is added according to the apparent viscosity until a semi-bio-based polyamide solution with a viscosity of 62010 mPa·s and a cross-linked structure is obtained; then, 120 kg of N,N-dimethylacetamide and 200 kg of water are added to the semi-bio-based polyamide solution, and the semi-bio-based polyamide particles with a cross-linked structure are obtained after pulping, washing, filtering and drying.

[0076] Into a stirring tank, 81.2 kg of N,N-dimethylacetamide, 10.3 kg of ceramic particles, 5.4 kg of the semi-bio-based polyamide prepared above, and 1.8 kg of polyvinylidene fluoride were added in sequence, and stirred for 2 hours to obtain a coating slurry; the coating slurry was applied to both sides of the lithium-ion battery base membrane, and after solvent extraction, water extraction, and drying at 75°C, a semi-bio-based polyamide membrane diaphragm with a cross-linked structure was prepared.

[0077] Example 3

[0078] Heat the 50L reactor to 80°C to completely dry the water, and use argon to replace the air in the reactor for 2 hours. After completion, add 28.44kg of N,N-dimethylformamide and 3.73kg of 4,4'-diaminodiphenyl ether into the reactor under the protection of argon, heat and stir to completely dissolve them; after dissolution, cool to 0°C to obtain a clear diamine solution. Take 3kg of 2,5-furandicarboxylic acid, first add 2.88g of 2,5-furandicarboxylic acid chloride to the reactor, control the addition rate to keep the temperature below 15°C, then quickly add 0.047kg of 1,3,5-triaminobenzene, and heat to 20-25°C and stir for 1h to obtain a polyamide prepolymer solution. The remaining 0.12g of 2,5-furandicarboxylic acid was added to the polyamide prepolymer solution, and the temperature was raised to 60-70°C for reaction for 5h. During this period, 0.031kg of 2,5-furandicarboxylic acid was added according to the apparent viscosity until a semi-bio-based polyamide solution with a cross-linked structure and a viscosity of 57790mPa·s was obtained. Then, 150kg of N,N-dimethylformamide and 300kg of water were added to the semi-bio-based polyamide solution to stir and precipitate the semi-bio-based polyamide, and then the semi-bio-based polyamide particles with a cross-linked structure were obtained after pulping, washing, filtration and drying.

[0079] 81.2 kg of N,N-dimethylacetamide, 10.3 kg of ceramic particles, 5.4 kg of the semi-bio-based polyamide prepared above, and 1.8 kg of polyvinylidene fluoride were added to the stirring tank in sequence, and the coating slurry was obtained after stirring for 2 hours; the coating slurry was applied to both sides of the lithium-ion battery base membrane, and after solvent extraction, water extraction, and drying at 75°C in sequence, a semi-bio-based polyamide membrane diaphragm with a cross-linked structure was obtained. The electron microscope image of the prepared semi-bio-based polyamide membrane diaphragm is shown in Figure 2 .

[0080] Example 4

[0081] Heat the 100L reactor to 85°C to completely dry the water, and use argon to replace the air in the reactor for 2 hours. After completion, add 46.825kg of N,N-dimethylacetamide and 4.99kg of 4,4'-diaminodiphenylmethane to the reactor under the protection of argon, heat and stir to completely dissolve them; after dissolution, cool to 0°C to obtain a clear diamine solution. Take 5kg of 2,5-furan dicarboxylic acid chloride, first add 4.75g of 2,5-furan dicarboxylic acid chloride to the reactor, control the addition rate to keep the temperature below 15°C, then quickly add 0.63kg of 1,3,5-triaminobenzene, and heat to 20-25°C and stir for 2h to obtain a polyamide prepolymer solution. The remaining 0.25g of 2,5-furandicarboxylic acid chloride was added to the polyamide prepolymer solution, and the temperature was raised to 60-70°C for reaction for 5.5h. During this period, 0.06kg of 2,5-furandicarboxylic acid chloride was added according to the apparent viscosity until a semi-bio-based polyamide solution with a cross-linked structure and a viscosity of 36300mPa·s was obtained. Then 200kg of N,N-dimethylacetamide was added to the semi-bio-based polyamide solution, and then 400kg of water was added thereto to stir and precipitate the semi-bio-based polyamide, and then the semi-bio-based polyamide particles with a cross-linked structure were obtained after pulping, water washing, suction filtration and drying.

[0082] 81.2 kg of N,N-dimethylacetamide, 10.3 kg of ceramic particles, 5.4 kg of the semi-bio-based polyamide prepared above, and 1.8 kg of polyvinylidene fluoride were added to the stirring tank in sequence, and the coating slurry was obtained after stirring for 2 hours; the coating slurry was applied to both sides of the lithium-ion battery base membrane, and after solvent extraction, water extraction, and drying at 75°C, a semi-bio-based polyamide membrane diaphragm with a cross-linked structure was obtained. After testing, the DSC curve of the prepared semi-bio-based polyamide membrane diaphragm in a nitrogen atmosphere is as follows Figure 1 The electron microscope image of the prepared semi-biobased polyamide membrane is shown in Figure 3 .

[0083] Example 5

[0084] Heat the 100L reactor to 80°C to completely dry the water, and use argon to replace the air in the reactor, which takes 2 hours. After completion, add 48.7kg of N,N-dimethylacetamide and 2.857kg of p-phenylenediamine to the reactor under the protection of argon, and stir to completely dissolve them; after dissolution, cool to 0°C to obtain a clear diamine solution. Take 5.2kg of 2,5-furandicarboxylic acid chloride, first add 5.096g of 2,5-furandicarboxylic acid chloride to the reactor, control the addition rate to keep the temperature below 10°C, then quickly add 0.122kg of 3,3',5,5'-tetraaminodiphenylmethane, and heat to 20-25°C and stir for 2h to obtain a polyamide prepolymer solution. The remaining 0.104g of 2,5-furandicarboxylic acid chloride was added to the polyamide prepolymer solution, and the temperature was raised to 60-70°C for reaction for 6h. During this period, 0.04kg of 2,5-furandicarboxylic acid chloride was added according to the apparent viscosity until a semi-bio-based polyamide solution with a cross-linked structure and a viscosity of 24090mPa·s was obtained. Then, 230kg of N,N-dimethylacetamide was added to the semi-bio-based polyamide solution, and 400kg of water was added thereto to stir and precipitate the semi-bio-based polyamide, and then the semi-bio-based polyamide particles with a cross-linked structure were obtained after pulping, washing, filtration and drying.

[0085] Into a stirring tank, 81.2 kg of N,N-dimethylacetamide, 10.3 kg of ceramic particles, 5.4 kg of the semi-bio-based polyamide prepared above, and 1.8 kg of polyvinylidene fluoride were added in sequence, and stirred for 2 hours to obtain a coating slurry; the coating slurry was applied to both sides of the lithium-ion battery base membrane, and after solvent extraction, water extraction, and drying at 75°C, a semi-bio-based polyamide membrane diaphragm with a cross-linked structure was prepared.

[0086] Example 6

[0087] Heat the 100L reactor to 80°C to completely dry the water, and use argon to replace the air in the reactor, which takes 2 hours. After completion, add 53.456kg of N-methylpyrrolidone and 2.857kg of m-phenylenediamine to the reactor under the protection of argon, heat and stir to completely dissolve them; after dissolution, cool to 0°C to obtain a clear diamine solution. Take 5.2kg of 2,5-furandicarboxylic acid chloride, first add 4.94g of 2,5-furandicarboxylic acid chloride to the reactor, control the addition rate to keep the temperature below 15°C, then quickly add 0.05kg of 1,3,5-triaminobenzene, and heat to 20-25°C and stir for 2h to obtain a polyamide prepolymer solution. The remaining 0.26g of 2,5-furandicarboxylic acid chloride was added to the polyamide prepolymer solution, and the temperature was raised to 60-70°C for reaction for 6h. During this period, 0.025kg of 2,5-furandicarboxylic acid chloride was added according to the apparent viscosity until a semi-bio-based polyamide solution with a cross-linked structure and a viscosity of 36900mPa·s was obtained. Then 200kg of N,N-dimethylacetamide was added to the semi-bio-based polyamide solution, and then 400kg of water was added thereto to stir and precipitate the semi-bio-based polyamide, and then the semi-bio-based polyamide particles with a cross-linked structure were obtained after pulping, washing, filtration and drying.

[0088] Into a stirring tank, 81.2 kg of N,N-dimethylacetamide, 10.3 kg of ceramic particles, 5.4 kg of the semi-bio-based polyamide prepared above, and 1.8 kg of polyvinylidene fluoride were added in sequence, and stirred for 2 hours to obtain a coating slurry; the coating slurry was applied to both sides of the lithium-ion battery base membrane, and after solvent extraction, water extraction, and drying at 75°C, a semi-bio-based polyamide membrane diaphragm with a cross-linked structure was prepared.

[0089] Example 7

[0090] Heat the 100L reactor to 80℃ to completely dry the water, and use argon to replace the air in the reactor, which takes 2h. After completion, add 46.825kg of N,N-dimethylacetamide and 5.036kg of 4,4'-diaminodiphenylmethane into the reactor under the protection of argon, heat and stir to completely dissolve them; after dissolution, cool to 0℃ to obtain a clear diamine solution. Take 5kg of 2,5-furandicarboxylic acid chloride, first add 4.9g of 2,5-furandicarboxylic acid chloride to the reactor, control the addition rate to keep the temperature below 15℃, then quickly add 0.117kg of 3,3',5,5'-tetraaminodiphenylmethane, and heat to 20-25℃ and stir for 2h to obtain a polyamide prepolymer solution. The remaining 0.1 g of 2,5-furandicarboxylic acid chloride was added to the polyamide prepolymer solution, and the temperature was raised to 60-70° C. to react for 6 hours. During this period, 0.029 kg of 2,5-furandicarboxylic acid chloride was added according to the apparent viscosity until a semi-bio-based polyamide solution containing a cross-linked structure with a viscosity of 50894 mPa·s was obtained; then 200 kg of N,N-dimethylacetamide was added to the semi-bio-based polyamide solution, and then 400 kg of water was added thereto to stir and precipitate the semi-bio-based polyamide, and then the semi-bio-based polyamide particles containing a cross-linked structure were obtained after pulping, washing, filtering and drying.

[0091] Into a stirring tank, 81.2 kg of N,N-dimethylacetamide, 10.3 kg of ceramic particles, 5.4 kg of the semi-bio-based polyamide prepared above, and 1.8 kg of polyvinylidene fluoride were added in sequence, and stirred for 2 hours to obtain a coating slurry; the coating slurry was applied to both sides of the lithium-ion battery base membrane, and after solvent extraction, water extraction, and drying at 75°C, a semi-bio-based polyamide membrane diaphragm with a cross-linked structure was prepared.

[0092] Example 8

[0093] Heat the 100L reactor to 80℃ to completely dry the water, and use argon to replace the air in the reactor, which takes 2h. After completion, add 46.825kg of N,N-dimethylacetamide and 5.032kg of 4,4'-diaminodiphenyl ether into the reactor under the protection of argon, heat and stir to completely dissolve them; after dissolution, cool to 0℃ to obtain a clear diamine solution. Take 5kg of 2,5-furan dicarboxylic acid chloride, first add 4.9g of 2,5-furan dicarboxylic acid chloride to the reactor, control the addition rate to keep the reaction temperature below 15℃, then quickly add 0.117kg of 3,3',5,5'-tetraaminodiphenylmethane, and heat to 20-25℃ and stir for 2h to obtain a polyamide prepolymer solution. The remaining 0.1 g of 2,5-furandicarboxylic acid chloride is added to the polyamide prepolymer solution, and the temperature is raised to 60-70° C. to react for 6 hours. During this period, 0.028 kg of 2,5-furandicarboxylic acid chloride is added according to the apparent viscosity until a semi-bio-based polyamide solution containing a cross-linked structure with a viscosity of mPa·s is obtained; then 200 kg of N,N-dimethylacetamide is added to the semi-bio-based polyamide solution, and then 420 kg of water is added thereto to stir and precipitate the semi-bio-based polyamide, and then the semi-bio-based polyamide particles containing a cross-linked structure are obtained after pulping, washing, filtering and drying.

[0094] Into a stirring tank, 81.2 kg of N,N-dimethylacetamide, 10.3 kg of ceramic particles, 5.4 kg of the semi-bio-based polyamide prepared above, and 1.8 kg of polyvinylidene fluoride were added in sequence, and stirred for 2 hours to obtain a coating slurry; the coating slurry was applied to both sides of the lithium-ion battery base membrane, and after solvent extraction, water extraction, and drying at 75°C, a semi-bio-based polyamide membrane diaphragm with a cross-linked structure was prepared.

[0095] Effect verification:

[0096] The performance of the semi-biobased polyamide diaphragm with a cross-linked structure prepared in Examples 1-8 was tested according to the existing testing technology in the art. The results are shown in Table 1 below:

[0097] Table 1 Performance test data of semi-biobased polyamide membrane containing cross-linked structure

[0098]

[0099] As shown in Table 1, the performance test data of the semi-bio-based polyamide membrane diaphragm prepared according to Examples 1 to 8, including air permeability, electrolyte absorption rate, tensile strength, and thermal shrinkage rate, fully demonstrate the excellent performance of the diaphragm material.

[0100] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A semi-biobased polyamide containing a cross-linked structure, characterized in that: The semi-biobased polyamide containing a cross-linked structure has the structure of the following formula (I): In formula (I), m>1, k>1 and m:k=(20-100):1, m+k=500-2000; Ar1 is a residue of a divalent aromatic amine, Ar2 is a residue of a trivalent aromatic amine, and R is a linear polymer chain cross-linked by the trivalent aromatic amine.

2. A method for preparing the semi-biobased polyamide containing a cross-linked structure according to claim 1, characterized in that: The following steps are involved: (1) mixing a diamine monomer with a first organic solvent under an inert gas atmosphere to obtain a diamine solution; (2) taking 2,5-furandicarboxylic acid or a derivative monomer thereof, adding part of the 2,5-furandicarboxylic acid or a derivative monomer thereof to the diamine solution, reacting at a first predetermined temperature, then adding a triamine monomer, and heating to a second predetermined temperature to obtain a polyamide prepolymer solution; (3) adding another portion of the 2,5-furandicarboxylic acid or its derivative monomer into the polyamide prepolymer solution, and then heating the solution to a third predetermined temperature to obtain a semi-biobased polyamide solution containing a cross-linked structure and having a desired apparent viscosity; (4) mixing the semi-bio-based polyamide solution with a second organic solvent, and then adding water to obtain semi-bio-based polyamide, and then pulping, washing, filtering, and drying the semi-bio-based polyamide to obtain semi-bio-based polyamide particles containing a cross-linked structure.

3. The method for preparing a semi-biobased polyamide containing a cross-linked structure according to claim 2, characterized in that: In step (1), the inert gas includes one or more of nitrogen, helium and argon; In step (1), the diamine monomer includes one or more of m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether, and 4,4'-diaminodiphenylmethane. In step (1), the mass ratio of the diamine monomer to the first organic solvent is 1:(5-10).

4. The method for preparing a semi-biobased polyamide containing a cross-linked structure according to claim 2, characterized in that: In step (1), after the diamine monomer is mixed with the first organic solvent, the method further comprises: heating to 60-80° C. to dissolve the diamine monomer, and then cooling to 0-10° C. to obtain the diamine solution.

5. The method for preparing a semi-biobased polyamide containing a cross-linked structure according to claim 2, characterized in that: In step (2), the derivative monomer of 2,5-furandicarboxylic acid is 2,5-furandicarboxylic acid chloride; In step (2), the triamine monomer includes one or more of 1,3,5-triaminobenzene, 1,1'-biphenyl-3,3',5,5'-tetramine and 3,3',5,5'-tetraaminodiphenylmethane.

6. The method for preparing a semi-biobased polyamide containing a cross-linked structure according to claim 2, characterized in that: In step (2), the mass ratio of the portion of 2,5-furandicarboxylic acid or a derivative monomer thereof to the 2,5-furandicarboxylic acid or a derivative monomer thereof is 95-99%; In step (2), the first predetermined temperature is no greater than 15°C; In step (2), the second predetermined temperature is 20-25°C; The molar ratio of the 2,5-furandicarboxylic acid or its derivative monomer to the diamine monomer is 1:(0.8-1); The molar ratio of the triamine monomer to the diamine monomer is (0.01-0.05):

1.

7. The method for preparing a semi-biobased polyamide containing a cross-linked structure according to claim 2, characterized in that: In step (3), the third predetermined temperature is 60-70°C; In step (3), the expected apparent viscosity is 10000-70000 mPa·s; In step (4), the mass of the semi-bio-based polyamide solution is 3-10 times the mass of the second organic solvent; the mass of the water is 8-10 times the mass of the semi-bio-based polyamide solution; The first organic solvent and the second organic solvent independently include at least one of N,N-dimethylacetamide, N-methylpyrrolidone and N,N-dimethylformamide.

8. A lithium ion battery separator, characterized in that: The raw material components of the diaphragm include, by weight: 0.8-1.5 parts of a third organic solvent, 0.01-0.5 parts of ceramic particles, 0.01-0.5 parts of semi-biobased polyamide, and 0.01-0.2 parts of polyvinylidene fluoride; Wherein, the semi-biobased polyamide is prepared by using the semi-biobased polyamide containing a cross-linked structure as claimed in claim 1 or by using the method as described in any one of claims 2-7.

9. A method for preparing the lithium ion battery separator according to claim 8, characterized in that: The following steps are involved: (1) mixing a third organic solvent, ceramic particles, semi-bio-based polyamide and polyvinylidene fluoride to obtain a semi-bio-based coating slurry; (2) The semi-bio-based coating slurry is coated on at least one side of a lithium-ion battery base membrane, and then subjected to mixed solvent extraction, water extraction, and drying to obtain a semi-bio-based polyamide separator containing a cross-linked structure.

10. The method for preparing a lithium ion battery separator according to claim 9, characterized in that: In step (2), the mixed solvent includes a fourth organic solvent and water, and the volume ratio of the fourth organic solvent to water is (0.1-2):1; The third organic solvent and the fourth organic solvent independently include at least one of N,N-dimethylacetamide, N-methylpyrrolidone and N,N-dimethylformamide.

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