Chitosan metal MOF modified polyurethane thermal insulation material and preparation method thereof

Abstract

The invention discloses a chitosan metal MOF modified polyurethane thermal insulation material and a preparation method thereof, and belongs to the field of polyurethane material preparation. The polyurethane thermal insulation material comprises the following raw materials in percentage by mass: 8-10% of metal MOF modified carboxymethyl chitosan, and a preparation method of the metal MOF modified carboxymethyl chitosan comprises the following steps: mixing a carboxymethyl chitosan solution, an organic ligand compound and a cross-linking agent to obtain a mixed solution, and adding metal salt into the mixed solution, stirring until the solid is completely dissolved, carrying out high-temperature reaction, filtering, washing, drying, and grinding to obtain the metal MOF structure modified carboxymethyl chitosan. The carboxymethyl chitosan is used as a main body, and an MOF material with numerous special independent spaces is introduced to modify the carboxymethyl chitosan, that is, the space structure of the carboxymethyl chitosan is modified while metal is introduced, so that the prepared polyurethane thermal insulation material has excellent thermal insulation effect and flame retardant effect.

Description

Technical Field

[0001] The invention relates to the field of preparation of polyurethane thermal insulation materials, and in particular to a chitosan metal MOF-modified polyurethane thermal insulation material and a preparation method thereof. Background Art

[0002] Organic thermal insulation materials are widely used in the fields of thermal insulation and energy storage due to their advantages such as light weight, low thermal conductivity and easy molding. At present, organic thermal insulation materials mainly include high molecular foam thermal insulation materials such as polyurethane, polystyrene or phenolic resin, among which polyurethane thermal insulation materials are mainly made by foaming isocyanate and hydroxyl compounds under polymerization. However, polyurethane thermal insulation materials, as a kind of high molecular foam material, have major defects. Their thermal insulation and flame retardancy are both poor, especially the problem of poor flame retardancy is the most serious. Polyurethane thermal insulation materials without added flame retardants or unmodified will burn and decompose when exposed to fire, producing a large amount of toxic smoke, which seriously limits the widespread application of polyurethane thermal insulation materials. Therefore, the development of a green, sustainable thermal insulation and flame retardant polyurethane thermal insulation material is of great significance to the development of the polyurethane industry.

[0003] Bio-based materials have good biodegradability and biocompatibility. Using bio-based materials to prepare polyurethane insulation materials is conducive to the sustainable development of the green economy. Carboxymethyl chitosan is a derivative of chitosan, a naturally available, low-cost polysaccharide polymer with the characteristics of biodegradability, biocompatibility, environmental friendliness and non-toxicity. Secondly, its molecular skeleton is carbon-rich and contains a certain number of side chain groups hydroxyl and amino groups. These groups can be used to load some metal elements, so that it has special physical and chemical properties to meet the insulation requirements, and can also construct the required spatial structure to further improve the insulation effect.

[0004] Based on this, the present invention starts from the structural characteristics of polyurethane polymer materials, takes carboxymethyl chitosan as the main body, introduces MOF materials with many special independent spaces to modify the carboxymethyl chitosan, and prepares a polyurethane thermal insulation material with excellent flame retardant properties. Summary of the invention

[0005] In view of the deficiencies of the above prior art, the present invention provides a chitosan metal MOF-modified polyurethane thermal insulation material, which takes carboxymethyl chitosan as the main body and introduces a MOF material with many special independent spaces to modify the carboxymethyl chitosan, so that the prepared polyurethane thermal insulation material has excellent thermal insulation effect and flame retardant effect.

[0006] To achieve the above purpose, the specific technical solutions of the present invention are as follows:

[0007] On the one hand, the present invention provides a chitosan metal MOF-modified polyurethane thermal insulation material, wherein the raw materials thereof include 8 to 10% by mass of metal MOF-modified carboxymethyl chitosan; the preparation method of the metal MOF-modified carboxymethyl chitosan includes: mixing a carboxymethyl chitosan solution, an organic ligand compound, and a cross-linking agent to obtain a mixed solution, adding a metal salt to the mixed solution and stirring until the solid is completely dissolved, then reacting at high temperature, filtering, washing, drying, and grinding to obtain carboxymethyl chitosan modified with a metal MOF structure.

[0008] The present invention first combines the hydroxyl / amino groups of the carboxymethyl chitosan side chain groups with an organic ligand compound through a cross-linking agent, and then complexes with the metal elements in the metal salt to form a stable three-dimensional network MOF structure with many special independent spaces to modify the carboxymethyl chitosan, that is, while introducing the metal, the spatial structure of the carboxymethyl chitosan is modified, so that the prepared polyurethane thermal insulation material has excellent thermal insulation effect and flame retardant effect.

[0009] Preferably, the mass ratio of the carboxymethyl chitosan, the organic ligand compound and the metal salt is (20-30):(8-15):1.

[0010] Preferably, the metal salt includes at least one of a metal copper salt and a metal iron salt.

[0011] Preferably, the metal salt is one or more of chloride salts, nitrate salts, sulfate salts and soluble organic salts of the corresponding metal.

[0012] Preferably, the organic ligand compound is selected from one or more of terephthalic acid, 2-aminoterephthalic acid, 2-hydroxyterephthalic acid, and 2,5-dihydroxyterephthalic acid.

[0013] Preferably, the cross-linking agent is at least one of 1-propylphosphoric acid cyclic anhydride, EDC (1-ethyl-(3-dimethylaminopropyl)carbodiimide), and NHS (N-hydroxysuccinimide).

[0014] Furthermore, the preparation method of the metal MOF modified carboxymethyl chitosan comprises the following steps:

[0015] S1, preparing a solution, dissolving carboxymethyl chitosan in an organic solvent to prepare a carboxymethyl chitosan solution; adding an organic ligand compound to deionized water, stirring at room temperature until dissolved, to obtain an organic ligand solution;

[0016] S2, mixing the carboxymethyl chitosan solution, the organic ligand solution, and the cross-linking agent, heating and stirring to obtain a mixed solution;

[0017] S3, adding metal salt to the mixed solution and stirring until the solid is completely dissolved, and then reacting at high temperature, cooling, filtering, washing, drying and grinding to obtain carboxymethyl chitosan modified with metal MOF structure.

[0018] Preferably, the heating temperature is 40-80°C, and the high temperature reaction temperature is 150-300°C.

[0019] Furthermore, the raw materials of the above-mentioned polyurethane thermal insulation material also include the following components in parts by weight: 25-45 parts of polyether polyol, 35-55 parts of isocyanate, 1-3 parts of catalyst, 1-2 parts of foaming agent, and 0.5-1 part of foam stabilizer.

[0020] The invention uses metal MOF-modified carboxymethyl chitosan containing metal MOF as a main raw material, adds various required additives, and prepares a chitosan-based polyurethane thermal insulation material with excellent mechanical properties, thermal insulation effect and flame retardant effect.

[0021] Another aspect of the present invention provides a method for preparing the above-mentioned polyurethane thermal insulation material, comprising the steps of:

[0022] The metal MOF-modified carboxymethyl chitosan and polyether polyol are mixed; then a foaming agent and a foam stabilizer are added and mixed; then a catalyst and isocyanate are added and mixed, and a polymerization reaction is carried out to obtain a chitosan metal MOF-modified polyurethane thermal insulation material.

[0023] Compared with the prior art, the present invention is beneficial in that:

[0024] 1. The present invention first combines the hydroxyl / amino groups of the carboxymethyl chitosan side chain groups with an organic ligand compound through a cross-linking agent, and then complexes with the metal elements in the metal salt to form a MOF material with many special independent spaces to modify the carboxymethyl chitosan, so that the prepared polyurethane thermal insulation material has excellent mechanical properties, thermal insulation effect and flame retardant effect.

[0025] 2. Carboxymethyl chitosan is naturally available, inexpensive, biodegradable, biocompatible, environmentally friendly and non-toxic. It can be used to prepare polyurethane insulation materials, which is low-cost, green, economical and environmentally friendly. DETAILED DESCRIPTION

[0026] The technical solution of the present invention will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] A chitosan metal MOF-modified polyurethane thermal insulation material, the raw materials of which include 8-10% by mass of metal MOF-modified carboxymethyl chitosan; the preparation method of the metal MOF-modified carboxymethyl chitosan includes: mixing a carboxymethyl chitosan solution, an organic ligand compound, and a cross-linking agent to obtain a mixed solution, adding a metal salt to the mixed solution and stirring until the solid is completely dissolved, then reacting at high temperature, filtering, washing, drying, and grinding to obtain carboxymethyl chitosan modified with a metal MOF structure.

[0028] In some examples, the mass ratio of the carboxymethyl chitosan, the organic ligand compound, and the metal salt is (20-30):(8-15):1.

[0029] In some examples, the metal salt includes at least one of a metal copper salt and a metal iron salt.

[0030] In some examples, the metal salt is one or more of chloride salts, nitrate salts, sulfate salts and soluble organic salts of the corresponding metal.

[0031] In some examples, the organic ligand compound is selected from one or more of terephthalic acid, 2-aminoterephthalic acid, 2-hydroxyterephthalic acid, and 2,5-dihydroxyterephthalic acid.

[0032] In some examples, the cross-linking agent may be at least one of 1-propylphosphonic acid cyclic anhydride, EDC, and NHS.

[0033] In some examples, the preparation method of the metal MOF modified carboxymethyl chitosan comprises the following steps:

[0034] S1, preparing a solution, dissolving carboxymethyl chitosan in an organic solvent to prepare a carboxymethyl chitosan solution; adding an organic ligand compound to deionized water, stirring at room temperature until dissolved, to obtain an organic ligand solution;

[0035] S2, mixing the carboxymethyl chitosan solution, the organic ligand solution, and the cross-linking agent, heating and stirring to obtain a mixed solution;

[0036] S3, adding metal salt to the mixed solution and stirring until the solid is completely dissolved, and then reacting at high temperature, cooling, filtering, washing, drying and grinding to obtain carboxymethyl chitosan modified with metal MOF structure.

[0037] In some examples, the heating temperature is 40-80°C, and the high temperature reaction temperature is 150-300°C.

[0038] In some examples, in addition to metal MOF-modified carboxymethyl chitosan, the polyurethane thermal insulation material also includes conventional raw materials commonly used or known in the art. For example, in a specific example, the polyurethane thermal insulation material also includes the following components by weight: 25-45 parts of polyether polyol, 35-55 parts of isocyanate, 1-3 parts of catalyst, 1-2 parts of foaming agent, and 0.5-1 part of foam stabilizer. These components can be selected from existing conventional raw materials.

[0039] In the following specific embodiments and comparative examples, unless otherwise specified, the metal iron salt is ferric nitrate, the metal copper salt is copper nitrate, the organic ligand compound is 2-aminoterephthalic acid, the cross-linking agent is 1-propyl phosphoric acid cyclic anhydride, the organic solvent is ethanol, the polyether polyol is polyether polyol DL-1000 (number average molecular weight of 1000, functionality of 2) and polyether polyol MN-700 (number average molecular weight of 1000, functionality of 3) with a mass ratio of 2.5:1, the isocyanate is hexamethylene diisocyanate, the catalyst is dibutyltin dilaurate, the foaming agent is n-pentane, and the foam stabilizer is silicone foam stabilizer AK-8805.

[0040] Example 1

[0041] A chitosan metal MOF-modified polyurethane thermal insulation material comprises the following components in parts by weight: 8 parts of metal MOF-modified carboxymethyl chitosan, 35 parts of polyether polyol, 52 parts of isocyanate, 2 parts of catalyst, 2 parts of foaming agent and 1 part of foam stabilizer.

[0042] The preparation method of metal MOF modified carboxymethyl chitosan comprises the following steps:

[0043] S1, preparing a solution, dissolving carboxymethyl chitosan in an organic solvent to prepare a carboxymethyl chitosan solution; adding an organic ligand compound to deionized water, stirring at room temperature until dissolved, to obtain an organic ligand solution;

[0044] S2, mixing the carboxymethyl chitosan solution, the organic ligand solution, and the cross-linking agent at 45° C. and stirring to obtain a mixed solution;

[0045] S3. Add metal salt to the mixed solution, stir until the solid is completely dissolved, react at 200° C. for 10 hours, cool, filter, wash, dry, grind, and pass through a 200-mesh sieve to obtain carboxymethyl chitosan modified with a metal MOF structure.

[0046] The mass ratio of the carboxymethyl chitosan, the organic ligand compound and the metal salt is 25:10:1. The metal salt is composed of iron nitrate and copper nitrate in a molar ratio of 2:3.

[0047] The preparation method of polyurethane thermal insulation material comprises the following steps: mixing metal MOF-modified carboxymethyl chitosan and polyether polyol; then adding a foaming agent and a foam stabilizer and mixing them; then adding a catalyst and an isocyanate and mixing them evenly, performing a polymerization reaction at 60°C for 25-30 minutes, and curing and forming to obtain a chitosan metal MOF-modified polyurethane thermal insulation material.

[0048] Example 2

[0049] A chitosan metal MOF-modified polyurethane thermal insulation material comprises the following components in parts by weight: 8 parts of metal MOF-modified carboxymethyl chitosan, 35 parts of polyether polyol, 52 parts of isocyanate, 2 parts of catalyst, 2 parts of foaming agent and 1 part of foam stabilizer.

[0050] The preparation method of metal MOF modified carboxymethyl chitosan comprises the following steps:

[0051] S1, preparing a solution, dissolving carboxymethyl chitosan in an organic solvent to prepare a carboxymethyl chitosan solution; adding an organic ligand compound to deionized water, stirring at room temperature until dissolved, to obtain an organic ligand solution;

[0052] S2, mixing the carboxymethyl chitosan solution, the organic ligand solution, and the cross-linking agent at 55° C. and stirring to obtain a mixed solution;

[0053] S3. Add metal salt to the mixed solution, stir until the solid is completely dissolved, react at 150° C. for 15 h, cool, filter, wash, dry, grind, and pass through a 200-mesh sieve to obtain carboxymethyl chitosan modified with a metal MOF structure.

[0054] The mass ratio of the carboxymethyl chitosan, the organic ligand compound and the metal salt is 30:15:1. The metal salt is ferric nitrate.

[0055] The preparation method of polyurethane thermal insulation material comprises the following steps: mixing metal MOF-modified carboxymethyl chitosan and polyether polyol; then adding a catalyst, a foaming agent and a foam stabilizer and mixing; then adding isocyanate and mixing, performing polymerization reaction at 60°C for 25-30 minutes, and curing and forming to obtain chitosan metal MOF-modified polyurethane thermal insulation material.

[0056] Example 3

[0057] A chitosan metal MOF-modified polyurethane thermal insulation material comprises the following components in parts by weight: 10 parts of metal MOF-modified carboxymethyl chitosan, 35 parts of polyether polyol, 50 parts of isocyanate, 2 parts of catalyst, 2 parts of foaming agent and 1 part of foam stabilizer.

[0058] The preparation method of metal MOF modified carboxymethyl chitosan comprises the following steps:

[0059] S1, preparing a solution, dissolving carboxymethyl chitosan in an organic solvent to prepare a carboxymethyl chitosan solution; adding an organic ligand compound to deionized water, stirring at room temperature until dissolved, to obtain an organic ligand solution;

[0060] S2, mixing the carboxymethyl chitosan solution, the organic ligand solution, and the cross-linking agent at 65° C. and stirring to obtain a mixed solution;

[0061] S3. Add metal salt to the mixed solution, stir until the solid is completely dissolved, react at 150° C. for 15 h, cool, filter, wash, dry, grind, and pass through a 200-mesh sieve to obtain carboxymethyl chitosan modified with a metal MOF structure.

[0062] The mass ratio of the carboxymethyl chitosan, the organic ligand compound and the metal salt is 20:8:1. The metal salt is copper nitrate.

[0063] The preparation method of polyurethane thermal insulation material comprises the following steps: mixing metal MOF-modified carboxymethyl chitosan and polyether polyol; then adding a catalyst, a foaming agent and a foam stabilizer and mixing; then adding isocyanate and mixing, performing polymerization reaction at 60°C for 25-30 minutes, and curing and forming to obtain chitosan metal MOF-modified polyurethane thermal insulation material.

[0064] Comparative Example 1

[0065] A polyurethane thermal insulation material, the preparation method is basically the same as that of Example 1, except that the raw material does not contain metal MOF-modified carboxymethyl chitosan, and the specific raw materials include the following components in parts by weight: 35 parts of polyether polyol, 52 parts of isocyanate, 2 parts of catalyst, 2 parts of foaming agent, and 1 part of foam stabilizer.

[0066] Comparative Example 2

[0067] A polyurethane thermal insulation material, the preparation method is basically the same as that of Example 1, except that an equal amount of carboxymethyl chitosan is used to replace the metal MOF-modified carboxymethyl chitosan, and the specific raw materials include the following components in parts by weight: 8 parts of carboxymethyl chitosan, 35 parts of polyether polyol, 52 parts of isocyanate, 2 parts of catalyst, 2 parts of foaming agent, and 1 part of foam stabilizer.

[0068] Comparative Example 3

[0069] A polyurethane thermal insulation material, the preparation method is basically the same as that of Example 1, except that an equal amount of metal frame material is used to replace the metal MOF-modified carboxymethyl chitosan, and the specific raw materials include the following components in parts by weight: 8 parts of metal frame material, 35 parts of polyether polyol, 52 parts of isocyanate, 2 parts of catalyst, 2 parts of foaming agent, and 1 part of foam stabilizer.

[0070] Preparation method of metal frame material:

[0071] S1. Adding the organic ligand compound into deionized water, stirring at room temperature until dissolved, to obtain an organic ligand solution;

[0072] S2. Add metal salt to the organic ligand solution, stir until the solid is completely dissolved, react at 200° C. for 10 hours, cool, filter, wash, dry, grind, and pass through a 200-mesh sieve to obtain a metal MOF framework material.

[0073] Comparative Example 4

[0074] A polyurethane thermal insulation material, the preparation method is basically the same as that of Example 1, except that an equal amount of the following modified substance is used to replace the metal MOF-modified carboxymethyl chitosan in Example 1, and the specific raw materials include the following components in parts by weight: 8 parts of modified substance, 35 parts of polyether polyol, 52 parts of isocyanate, 2 parts of catalyst, 2 parts of foaming agent, and 1 part of foam stabilizer.

[0075] Preparation method of modified substance:

[0076] S1, preparing a solution, dissolving carboxymethyl chitosan in an organic solvent to prepare a carboxymethyl chitosan solution; adding an organic ligand compound to deionized water, stirring at room temperature until dissolved, to obtain an organic ligand solution;

[0077] S2, adding metal salt to the organic ligand solution and stirring until the solid is completely dissolved, reacting at 200°C for 10 hours, cooling, filtering, and grinding to 200 mesh to obtain a metal MOF framework material;

[0078] S3. Mix the carboxymethyl chitosan solution, the crosslinking agent and the metal MOF framework material, stir evenly at 65° C., cool, filter, wash, dry, grind and pass through a 200-mesh sieve to obtain a modified substance.

[0079] Application test

[0080] 1. Limiting oxygen index test

[0081] The polyurethane thermal insulation materials in Examples 1-3 and Comparative Examples 1-4 were processed into standard test specimens (width b is about 10 mm, height h is about 3 mm, and length l is about 125 mm). The LOI value of the specimen was measured by an oxygen index measuring instrument. The specimen to be tested was fixed on a combustion rack, and the flow rates of N2 and O2 were adjusted to a certain fixed value. The specimen to be tested was ignited to observe whether the specimen to be tested could self-extinguish within 3 minutes. If it could not self-extinguish, the flow rate of N2 was increased. If it could not ignite, the flow rate of O2 was increased. Repeat the test until it self-extinguished to determine the limiting oxygen index of the specimen. The test results are shown in Table 1.

[0082] 2. Thermal conductivity test

[0083] The polyurethane thermal insulation materials of Examples 1-3 and Comparative Examples 1-4 were tested for thermal conductivity according to GB / T 10294-2008. The test results are shown in Table 1.

[0084] Table 1 Test results of Examples 1-3 and Comparative Examples 1-4:

[0085]

[0086] It can be seen from Table 1 that the limiting oxygen index of Examples 1-3 is 38.4% or above, and the thermal conductivity is as low as below 0.0145 W / (m·K), which indicates that the polyurethane foam material to which the metal MOF-modified carboxymethyl chitosan of the present invention is added has excellent thermal insulation and flame retardant properties.

[0087] Compared with Example 1, Comparative Example 1 does not contain the metal MOF modified carboxymethyl chitosan of the present invention, Comparative Example 2 uses unmodified carboxymethyl chitosan, Comparative Example 3 uses only a single metal MOF framework material, and Comparative Example 4 directly uses a substance obtained by mixing carboxymethyl chitosan and a metal MOF framework material, and the carboxymethyl chitosan does not preferentially combine with an organic ligand, so that the limiting oxygen index of the prepared polyurethane thermal insulation material is significantly reduced, and the thermal conductivity is significantly higher than that of Example 1. This is mainly because the present invention first combines the hydroxyl / amino group of the carboxymethyl chitosan side chain with an organic ligand compound through a cross-linking agent, and then complexes with the metal element in the metal salt to form a MOF material with many special independent spaces to modify the carboxymethyl chitosan, so that the prepared polyurethane thermal insulation material has a better thermal insulation effect and flame retardant effect.

[0088] The above specific embodiments describe the implementation of the present invention in detail, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the claims and technical concept of the present invention, the technical solution of the present invention can be modified and changed in many simple ways, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A chitosan metal MOF modified polyurethane thermal insulation material, characterized in that: The raw materials include 8-10% by mass of metal MOF-modified carboxymethyl chitosan; the preparation method of the metal MOF-modified carboxymethyl chitosan includes: mixing a carboxymethyl chitosan solution, an organic ligand compound, and a cross-linking agent to obtain a mixed solution, adding a metal salt to the mixed solution and stirring until the solid is completely dissolved, then reacting at high temperature, filtering, washing, drying, and grinding to obtain the metal MOF-modified carboxymethyl chitosan.

2. The chitosan metal MOF-modified polyurethane thermal insulation material according to claim 1, characterized in that: The mass ratio of the carboxymethyl chitosan, the organic ligand compound and the metal salt is (20-30):(8-15):

1.

3. The chitosan metal MOF-modified polyurethane thermal insulation material according to claim 1, characterized in that: The metal salt includes at least one of a metal copper salt and a metal iron salt.

4. The chitosan metal MOF-modified polyurethane thermal insulation material according to claim 3, characterized in that: The metal salt is one or more of chloride salts, nitrate salts, sulfate salts and soluble organic salts of the corresponding metal.

5. The chitosan metal MOF modified polyurethane thermal insulation material according to claim 1, characterized in that: The organic ligand compound is selected from one or more of terephthalic acid, 2-aminoterephthalic acid, 2-hydroxyterephthalic acid, and 2,5-dihydroxyterephthalic acid.

6. The chitosan metal MOF modified polyurethane thermal insulation material according to claim 1, characterized in that: The cross-linking agent is at least one of 1-propylphosphoric acid cyclic anhydride, EDC and NHS.

7. The chitosan metal MOF-modified polyurethane thermal insulation material according to claim 1, characterized in that: The preparation method of the metal MOF modified carboxymethyl chitosan comprises the following steps: S1, preparing a solution, dissolving carboxymethyl chitosan in an organic solvent to prepare a carboxymethyl chitosan solution; adding an organic ligand compound to deionized water, stirring at room temperature until dissolved, to obtain an organic ligand solution; S2, mixing the carboxymethyl chitosan solution, the organic ligand solution, and the cross-linking agent, heating and stirring to obtain a mixed solution; S3, adding metal salt to the mixed solution and stirring until the solid is completely dissolved, and then reacting at high temperature, cooling, filtering, washing, drying and grinding to obtain carboxymethyl chitosan modified with metal MOF structure.

8. The chitosan metal MOF-modified polyurethane thermal insulation material according to claim 7, characterized in that: The heating temperature is 40-80°C, and the high temperature reaction temperature is 150-300°C.

9. The chitosan metal MOF-modified polyurethane thermal insulation material according to claim 1, characterized in that: The raw materials also include the following components in parts by weight: 25-45 parts of polyether polyol, 35-55 parts of isocyanate, 1-3 parts of catalyst, 1-2 parts of foaming agent and 0.5-1 part of foam stabilizer.

10. The method for preparing the polyurethane thermal insulation material according to any one of claims 1 to 9, characterized in that: Includes steps: The metal MOF-modified carboxymethyl chitosan and polyether polyol are mixed; then a foaming agent and a foam stabilizer are added and mixed; then a catalyst and isocyanate are added and mixed, and a polymerization reaction is carried out to obtain a chitosan metal MOF-modified polyurethane thermal insulation material.

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