BGAP-PEG400 polyurethane elastic material as well as preparation method and application thereof

Abstract

The invention discloses a BGAP-PEG400 polyurethane elastic material as well as a preparation method and application thereof, and the BGAP-PEG400 polyurethane elastic material is prepared from the following raw materials in percentage by mass: 35-38% of branched glycidyl azide polymer, 10-20% of polyisobutylene glycol, 10-20% of polyisobutylene glycol, 10-20% of polyisobutylene glycol, 10-20% of polyisobutylene glycol, 10-20% of polyisobutylene glycol, 10-20% of a The content of the n-butyl nitroxyethyl nitramine is 35%-45.6%, the content of the trimethylolpropane is 2.2%-2.4%, and the content of the polyethylene glycol is 3.5%-3.8%; the triphenyl bismuth accounts for 0.3%-0.5%, the curing agent accounts for 5%-15%, and the sum of the mass percentages of all the components is 100%; the preparation method comprises the following steps: blending branched glycidyl azide polymer (BGAP) and polyethylene glycol 400 (PEG400), and preparing the BGAP-PEG400 polyurethane elastic material with more excellent mechanical properties by taking n-butyl nitroxyethyl nitramine as a plasticizer, trimethylolpropane as a cross-linking agent and triphenyl bismuth as a catalyst and using a compound curing agent. The preparation method of the BGAP-PEG400 polyurethane elastic material disclosed by the invention is simple, chain extension does not need to be carried out on the glycidyl azide polymer, and the advantages of relatively high flexibility and small molecular weight of a PEG400 molecular chain are fully exerted.

Description

Technical Field

[0001] The present invention belongs to the field of energetic materials and relates to a BGAP-PEG400 polyurethane elastic material, a preparation method and an application thereof. Background Art

[0002] To ensure the safety of missile launch positions, the requirements for the range and concealment of missiles are getting higher and higher, and traditional propellants can no longer meet the needs. As a new type of energetic binder, glycidyl azide polymer (GAP) has broad prospects in the application of missile propellants due to its characteristics of low sensitivity, high energy and low signature.

[0003] Although GAP-based propellants have good mechanical sensitivity and high energy, and can meet the safety performance and energy requirements of propellants, the large polar azide groups on the side chains of GAP-based propellant molecules affect their mechanical properties. Therefore, the modification of GAP binders has become an important direction in the research and development of GAP-based propellants. Zhao Yu et al. studied the influencing factors of the mechanical properties of GAP-based polyurethane elastomers and found that when the mass fraction of the crosslinking agent trimethylolpropane increased from 0 to 0.5%, the maximum tensile strength of the polyurethane elastomer increased from 0.24 MPa to 0.32 MPa, and the elongation at break decreased from 558.7% to 278.5%. The insufficient mechanical properties of the propellant will cause it to separate from the coating layer during application, resulting in accidents. Therefore, how to prepare a GAP-based polyurethane elastomer with greater tensile strength and greater elongation at break has important practical significance. Summary of the Invention

[0004] Aiming at the defects and deficiencies existing in the prior art, the purpose of the present invention is to provide a BGAP-PEG400 polyurethane elastic material, a preparation method and an application thereof to further improve the mechanical properties of GAP-based propellants.

[0005] To solve the above technical problems, the present invention adopts the following technical solutions:

[0006] A preparation method of a BGAP-PEG400 polyurethane elastic material, which is prepared from the following raw materials by mass percentage to prepare the BGAP-PEG400 polyurethane elastic material:

[0007] Branched glycidyl azide polymer is 35% - 38%; n-butyl nitroxide ethyl nitramine is 35% - 45.6%, trimethylolpropane is 2.2% - 2.4%, polyethylene glycol is 3.5% - 3.8%; triphenylbismuth accounts for 0.3% - 0.5%, and the curing agent is 5% - 15%. The sum of the mass percentages of each component is 100%;

[0008] The method includes the following steps:

[0009] Step 1: Add the branched polyazidoglycidyl ether, n-butyl nitroxylethyl nitramine, trimethylolpropane, polyethylene glycol 400, and triphenylbismuth in the formula amounts into a container. After stirring and mixing and standing still, solution A is obtained.

[0010] Step 2: Place the container containing solution A into a vacuum dryer. After performing vacuum pumping at room temperature, add the curing agent in the formula amount. After stirring, solution B is obtained.

[0011] Step 3: Pour solution B into a polytetrafluoroethylene mold. After standing still, performing vacuum pumping at room temperature, and curing at 45 - 55°C for 7 - 10 days, the BGAP-PEG400 polyurethane elastic material is obtained.

[0012] The present invention also has the following technical features:

[0013] Specifically, the plasticization ratio of the n-butyl nitroxylethyl nitramine to the branched polyazidoglycidyl ether is 0.9 - 1.1.

[0014] Furthermore, in step 1, the stirring and mixing temperature is 45 - 55°C, and the stirring and mixing time is 3 - 5 h; the standing still temperature is 45 - 55°C, and the standing still time is 22 - 25 h;

[0015] In step 2, the total amount of hydroxyl groups contained in the trimethylolpropane is 60% - 65% of the total amount of hydroxyl groups in solution B.

[0016] Furthermore, the curing parameters of the curing agent are 1.7 - 1.8.

[0017] Furthermore, the curing agent is compounded from 2,4-toluene diisocyanate and hexamethylene diisocyanate, and the mass ratio of the 2,4-toluene diisocyanate to the hexamethylene diisocyanate is 2:1.

[0018] Furthermore, the curing agent is compounded from 2,4-toluene diisocyanate and polyisocyanate, and the mass ratio of the 2,4-toluene diisocyanate to the polyisocyanate is 2:1.

[0019] Furthermore, it includes the following steps:

[0020] Step 1: Add 36 g of branched polyazidoglycidyl ether, 39.6 g of n-butyl nitroxylethyl nitramine, 2.1 g of trimethylolpropane, 3.6 g of polyethylene glycol 400, and 0.26 g of triphenylbismuth into a container. Stir at 50°C for 4 h, and then place at 50°C for 24 h to obtain solution A.

[0021] Step 2: Place the container holding Solution A into a vacuum dryer. After performing vacuum pumping at room temperature, add 7.5 g of 2,4-toluene diisocyanate and 3.8 g of hexamethylene diisocyanate, and stir for 30 min to obtain Solution B;

[0022] Step 3: Pour Solution B into a polytetrafluoroethylene mold, let it stand, perform vacuum pumping at room temperature, and cure at 50 °C for 7 days to obtain the product.

[0023] The present invention also protects a BGAP-PEG400 polyurethane elastic material, which is prepared by the above preparation method.

[0024] The present invention also protects the application of the BGAP-PEG400 polyurethane elastic material prepared by the above preparation method in the preparation of composite solid propellants.

[0025] The present invention also protects the application of the above BGAP-PEG400 polyurethane elastic material in the preparation of composite solid propellants. Compared with the prior art, the present invention has the following technical effects:

[0026] (1) The preparation method of the BGAP-PEG400 polyurethane elastic material disclosed in the present invention is simple. There is no need to perform chain extension on poly(glycidyl azide), reducing the material input, and giving full play to the advantages of the PEG400 molecular chain with high flexibility and relatively small molecular weight; the main components PEG400 and BGAP both belong to high molecular weight terminal hydroxyl polyethers, and they have good compatibility and will not decompose spontaneously.

[0027] (2) The polyurethane elastomer provided by the present invention has fewer impurities. While increasing the elongation at break, the maximum tensile strength has also been significantly improved. For example, the elongation at break is greater than 350%, and the maximum tensile strength is 2 MPa. Description of the Drawings

[0028] Figure 1 is the BGAP-PEG400 polyurethane elastomer prepared in Example 1;

[0029] Figure 2 is the infrared spectrum of the polyurethane elastomer prepared in Example 1;

[0030] Figure 3 is the SEM image of the fracture surface after tensile fracture of the polyurethane elastomer prepared in Example 1;

[0031] Figure 4 is the DSC diagram of the polyurethane elastomer prepared in Example 1;

[0032] The following further details the specific content of the present invention in conjunction with the drawings and examples. Detailed Embodiments

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by any ordinary person skilled in the art belong to the scope of protection of the present invention.

[0034] It should be noted that all raw materials, experimental equipment, and detection equipment in the present invention are, without special instructions, the raw materials and equipment known in the art.

[0035] The technical concept of this application is as follows: As a polymer with a very flexible molecular chain, PEG400 has advantages such as a mature preparation process, being cheap and easily available; compared with linear poly(glycidyl azide) (GAP), branched poly(glycidyl azide) (BGAP) is more likely to form a complex polymer network. When the relative molecular mass is the same, branched poly(glycidyl azide) (BGAP) has a lower viscosity than linear poly(glycidyl azide) (GAP), and can improve the mechanical properties at the molecular level. By blending BGAP with PEG400, using n-butyl nitroxide ethyl nitramine as a plasticizer, trimethylolpropane as a crosslinking agent, triphenylbismuth as a catalyst, and using a compound curing agent, a BGAP-PEG400 polyurethane elastic material with more excellent mechanical properties can be prepared.

[0036] In the present invention, both branched poly(glycidyl azide) (BGAP) and polyethylene glycol (PEG400) are the branched poly(glycidyl azide) (BGAP) and polyethylene glycol (PEG400) known in the art. Preferably, the number average molecular weight of branched poly(glycidyl azide) (BGAP) is 2000. The degree of polymerization of polyethylene glycol 400 (PEG400) is 400.

[0037] Following the above technical solutions, the specific embodiments of the present invention are given below. It should be noted that the present invention is not limited to the following specific embodiments, and all equivalent transformations made on the basis of the technical solutions of this application fall within the scope of protection of the present invention.

[0038] Example 1

[0039] Following the above technical solutions, this example discloses a preparation method of a BGAP-PEG400 polyurethane elastic material, including the following steps:

[0040] Step 1: Add 36 g of branched poly(glycidyl azide) (BGAP), 39.6 g of n-butyl nitroxide ethyl nitramine, 2.1 g of trimethylolpropane, 3.6 g of polyethylene glycol 400 (PEG400), and 0.26 g of triphenylbismuth into a container, stir at 50 °C for 4 h, and then place it at 50 °C for 24 h to obtain solution A;

[0041] Step 2, placing the container containing solution A in a vacuum dryer, performing vacuum treatment at room temperature, adding 7.5 g of 2,4-toluene diisocyanate and 3.8 g of hexamethylene diisocyanate, and stirring for 30 min to obtain solution B;

[0042] Step 3, pour solution B into a polytetrafluoroethylene mold, and after the liquid is leveled, place the polytetrafluoroethylene mold in a vacuum dryer and perform vacuum treatment at room temperature; place the vacuum treated mold in a 50°C oven for curing for 7 days to obtain;

[0043] In this embodiment, the plasticization ratio of n-butyl nitroxyethyl nitramine to BGAP is 1.1.

[0044] Structural characterization of the BGAP-PEG400 polyurethane elastic material obtained in this example:

[0045] from Figure 2 The infrared spectrum shows that at 3331cm -1 The characteristic peak of the -NH group of polyurethane appeared; 1635cm -1 The characteristic peak of the C═O group of polyurethane appeared, indicating that the elastic material prepared in this example belongs to the category of polyurethane.

[0046] from Figure 3 It can be seen that the cross section of the BGAP-PEG400 polyurethane elastomer prepared in this embodiment is very rough and has shallow texture after being stretched to pieces, indicating that the molecular network is relatively complex and the branches are intertwined. Therefore, the molecules are tightly cross-linked and entangled during the stretching process, and stress can be quickly transmitted to the entire network of molecules when applied.

[0047] from Figure 4 It can be seen that the peak of the spectrum of the BGAP-PEG400 polyurethane elastomer prepared in this example substantially coincides with the peaks of BGAP and n-butyl nitroxyethyl nitramine, indicating that PEG400 and BGAP have good compatibility.

[0048] Performance Test:

[0049] The maximum tensile strength and elongation at break of the BGAP-PEG400 polyurethane elastomer prepared in this example were tested according to the standard of GB_T528_2005_20D-1 at 20°C and 500 mm / min. The results are shown in Table 1.

[0050] Application of BGAP-PEG400 polyurethane elastic material:

[0051] The BGAP-PEG400 polyurethane elastic material prepared in this example should be able to be used for preparing composite solid propellants or composite modified double-base propellants. Among them, the composite solid propellant is prepared by an existing method and, by mass percentage, includes the following raw material components: oxidizer component 60%, metal powder 18%, BGAP-PEG400 polyurethane elastic material 17.95% and other components 4.05%.

[0052] Example 2

[0053] In this example, a preparation method of BGAP-PEG400 polyurethane elastic material is disclosed. The raw material components and steps used in the preparation are the same as those in Example 1, except that the addition amount of n-butyl nitroxide ethyl nitramine is different. In this example, the addition amount of n-butyl nitroxide ethyl nitramine is 36 g, and the plasticization ratio of n-butyl nitroxide ethyl nitramine to BGAP is 1. In this example, the BGAP-PEG400 polyurethane elastic material is finally prepared.

[0054] Performance test:

[0055] The maximum tensile strength and elongation at break of the BGAP-PEG400 polyurethane elastomer prepared in this example were tested according to the standard of GB_T528_2005_20D-1 at 20 °C and 500 mm / min, and the results are shown in Table 1.

[0056] Example 3

[0057] In this example, a preparation method of BGAP-PEG400 polyurethane elastic material is disclosed. The raw material components and steps used in the preparation are the same as those in Example 1, except that the addition amount of n-butyl nitroxide ethyl nitramine is different. In this example, the addition amount of n-butyl nitroxide ethyl nitramine is 32.4 g, that is, the plasticization ratio of n-butyl nitroxide ethyl nitramine to BGAP is 0.9. In this example, the BGAP-PEG400 polyurethane elastic material is finally prepared.

[0058] Performance test:

[0059] The maximum tensile strength and elongation at break of the BGAP-PEG400 polyurethane elastomer prepared in this example were tested according to the standard of GB_T528_2005_20D-1 at 20 °C and 500 mm / min, and the results are shown in Table 1.

[0060] Example 4

[0061] In this example, a preparation method of BGAP-PEG400 polyurethane elastic material is disclosed. The raw material components and steps used in the preparation are the same as those in Example 1, except that the addition amount of n-butyl nitroxide ethyl nitramine is different. In this example, the addition amount of n-butyl nitroxide ethyl nitramine is 28.8 g, that is, the plasticization ratio of n-butyl nitroxide ethyl nitramine to BGAP is 0.8. In this example, BGAP-PEG400 polyurethane elastic material is finally prepared.

[0062] Performance test:

[0063] The maximum tensile strength and elongation at break of the BGAP-PEG400 polyurethane elastomer prepared in this example were tested according to the standard of GB_T528_2005_20D-1 at 20 °C and 500 mm / min, and the results are shown in Table 1.

[0064] Example 5

[0065] In this example, a preparation method of BGAP-PEG400 polyurethane elastic material is disclosed. The raw material components and steps used in the preparation are the same as those in Example 1, except that the addition amount of n-butyl nitroxide ethyl nitramine is different. In this example, the addition amount of n-butyl nitroxide ethyl nitramine is 54 g, that is, the plasticization ratio of n-butyl nitroxide ethyl nitramine to BGAP is 1.5. In this example, BGAP-PEG400 polyurethane elastic material is finally prepared.

[0066] Performance test:

[0067] The maximum tensile strength and elongation at break of the BGAP-PEG400 polyurethane elastomer prepared in this example were tested according to the standard of GB_T528_2005_20D-1 at 20 °C and 500 mm / min, and the results are shown in Table 1.

[0068] Example 6

[0069] In this example, a preparation method of BGAP-PEG400 polyurethane elastic material is disclosed. The raw material components and steps used in the preparation are the same as those in Example 1, except that in this example, the curing agent is composed of a mixture of 2,4-toluene diisocyanate and polyisocyanate. In this example, BGAP-PEG400 polyurethane elastic material is finally prepared.

[0070] Comparative Example 1

[0071] In this comparative example, linear polyglycidyl azide ether (GAP) was used to replace branched polyglycidyl azide ether, and the preparation method of GAP-based polyurethane elastic material disclosed in Example 1 was used for preparation. Finally, GAP-based polyurethane elastic material was not obtained.

[0072] Comparative Example 2

[0073] This example discloses a preparation method of GAP-based polyurethane elastic material, and the preparation steps are as follows:

[0074] Step 1: Add 36 g of linear polyglycidyl azide, 18 g of n-butyl nitroxylethyl nitramine, 3.22 g of trimethylolpropane, 3.6 g of polyethylene glycol 400 and 0.26 g of triphenylbismuth into a container, stir at 50 °C for 4 h, and then place it at 50 °C for 24 h to obtain Solution A;

[0075] Step 2: Put the container containing Solution A into a vacuum dryer, carry out vacuum treatment at room temperature, and then add 11.6 g of 2,4-toluene diisocyanate and 5.2 g of hexamethylene diisocyanate, and stir for 30 min to obtain Solution B;

[0076] Step 3: Pour Solution B into a polytetrafluoroethylene mold. After the liquid levels off, put the polytetrafluoroethylene mold into a vacuum dryer and carry out vacuum treatment at room temperature; put the vacuum-treated mold into an oven at 50 °C for curing for 7 days to obtain the product.

[0077] In this comparative example, the plasticization ratio (mass ratio) of n-butyl nitroxylethyl nitramine to linear polyglycidyl azide is 0.5.

[0078] Performance test:

[0079] The maximum tensile strength and elongation at break of the BGAP-PEG400 polyurethane elastomer prepared in this comparative example were tested, and the results are shown in Table 1.

[0080]

[0081] Table 1. Performance test results of Examples 1-4 and Comparative Example 2

[0082] It can be seen from Examples 1-6 and Comparative Example 2 that: compared with linear polyglycidyl azide, the mechanical properties of the elastic material prepared by using branched polyglycidyl azide have been significantly improved.

[0083] In Examples 1 to 3, n-butyl nitroxide ethyl nitramine was used as a plasticizer, and the range of the plasticization ratio was 0.9 to 1.1 (the plasticization ratio was reflected by the mass ratio of n-butyl nitroxide ethyl nitramine and BGAP. When the mass of the added n-butyl nitroxide ethyl nitramine was 1.1 times that of BGAP, the plasticization ratio was 1.1). The increase in the plasticization ratio would increase the elongation at break and slightly decrease the maximum tensile strength. However, the elongation at break of the BGAP-PEG400 polyurethane elastomer prepared by the method of the present invention was greater than 350%, and the maximum tensile strength was above 2 MPa, which was significantly higher than that of the GAP-based polyurethane elastic material prepared from linear polyglycidyl azide ether in Comparative Example 2.

[0084] In Examples 4 and 5, although elastic materials were also prepared, the mechanical properties of the prepared elastic materials were significantly inferior to those in Examples 1 to 3, indicating that the plasticization ratio had a significant impact on the properties of the elastic materials.

[0085] The plasticizer used in the present invention is a small molecule substance, which can play a lubricating role in the polymer chain, greatly reduce the viscosity of the polymer solution, improve the mechanical properties of the cured elastomer, reduce the tensile strength and increase the elongation at break. Moreover, the degree of change in mechanical properties is not linear with the change in the plasticization ratio. When the plasticization ratio exceeds a certain range, the proportion of the polymer chain in the elastomer is too small, which will make the elastomer too soft, resulting in a decrease in the tensile strength of the elastomer and a small change in the elongation at break.

[0086] Although the BGAP-PEG400 polyurethane elastic material was also prepared in Example 6, since the curing agent component contained polyisocyanate and the molecular structure of polyisocyanate had poor regularity, the mechanical properties of the elastomer prepared in Example 4 decreased compared with those in Examples 1 to 3.

[0087] It can be seen from Examples 1, Comparative Example 1 and Comparative Example 2 that in Comparative Example 1, linear polyglycidyl azide ether (GAP) was used to replace branched polyglycidyl azide ether. Although other raw material components and reaction conditions were the same, no polyurethane elastic material was prepared. Compared with Comparative Example 1, an elastic material was prepared in Comparative Example 2. This was because although the plasticizer (n-butyl nitroxide ethyl nitramine) could increase the fluidity of the liquid, it would also reduce the concentration of the reaction components. In Comparative Example 2, due to the small addition amount of the plasticizer (the plasticization ratio was 0.5), the degree of reduction in the concentration of the reaction components by the plasticizer was limited, and an elastic material was prepared. However, from the performance test results of Example 1 and Comparative Example 2, it can be seen that the elastic material prepared from branched polyglycidyl azide ether had more excellent mechanical properties than the elastic material prepared from linear polyglycidyl azide ether.

[0088] The preferred embodiments of the present disclosure have been described in detail above in conjunction with the accompanying drawings. However, the present disclosure is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present disclosure, various simple modifications can be made to the technical solutions of the present disclosure, and these simple modifications all fall within the protection scope of the present disclosure.

[0089] In addition, it should be noted that, in the various specific technical features described in the above specific embodiments, they can be combined in any appropriate manner without conflict. To avoid unnecessary repetition, the present disclosure will not separately describe various possible combination manners.

[0090] Furthermore, any combination can be made between various different embodiments of the present disclosure, as long as it does not violate the idea of the present disclosure, and it should also be regarded as the content disclosed by the present disclosure.

Claims

1. A method for preparing a BGAP-PEG400 polyurethane elastic material, characterized in that: The method prepares BGAP-PEG400 polyurethane elastic material from the following raw materials in terms of mass percentage: The branched polyazide glycidyl ether is 35% to 38%; the n-butyl nitroxyethyl nitramine is 35% to 45.6%, the trimethylolpropane is 2.2% to 2.4%, the polyethylene glycol is 3.5% to 3.8%; the triphenyl bismuth is 0.3% to 0.5%, the curing agent is 5% to 15%, and the sum of the mass percentages of each component is 100%; The method comprises the following steps: Step 1, adding a formulated amount of branched polyazide glycidyl ether, n-butyl nitroxyethyl nitramine, trimethylolpropane, polyethylene glycol 400 and triphenyl bismuth into a container, stirring and mixing, and standing to obtain a solution A; Step 2, placing the container containing solution A into a vacuum dryer, performing vacuum treatment at room temperature, adding a formulated amount of curing agent, and stirring to obtain solution B; Step 3: Pour solution B into a polytetrafluoroethylene mold, let it stand, evacuate at room temperature, and cure it at 45-55° C. for 7-10 days to obtain BGAP-PEG400 polyurethane elastic material.

2. The method for preparing the BGAP-PEG400 polyurethane elastic material according to claim 1, characterized in that: The plasticizing ratio of the n-butyl nitroxyethyl nitramine to the branched polyazide glycidyl ether is 0.9 to 1.

1.

3. The method for preparing the BGAP-PEG400 polyurethane elastic material according to claim 1, characterized in that: In the step 1, the stirring and mixing temperature is 45-55°C, and the stirring and mixing time is 3-5h; the standing temperature is 45-55°C, and the standing time is 22-25h; In step 2, the total amount of hydroxyl groups contained in the trimethylolpropane is 60% to 65% of the total amount of hydroxyl groups in solution B.

4. The method for preparing the BGAP-PEG400 polyurethane elastic material according to claim 1, characterized in that: The curing parameter of the curing agent is 1.7 to 1.

8.

5. The method for preparing the BGAP-PEG400 polyurethane elastic material according to claim 4, characterized in that: The curing agent is compounded by 2,4-toluene diisocyanate and hexamethylene diisocyanate, and the mass ratio of the 2,4-toluene diisocyanate to the hexamethylene diisocyanate is 2:

1.

6. The method for preparing the BGAP-PEG400 polyurethane elastic material according to claim 4, characterized in that: The curing agent is compounded by 2,4-toluene diisocyanate and polyisocyanate, and the mass ratio of the 2,4-toluene diisocyanate to the polyisocyanate is 2:

1.

7. The method for preparing the BGAP-PEG400 polyurethane elastic material according to claim 1, characterized in that: The following steps are involved: Step 1, 36 g of branched polyazide glycidyl ether, 39.6 g of n-butyl nitroxyethyl nitramine, 2.1 g of trimethylolpropane, 3.6 g of polyethylene glycol 400 and 0.26 g of triphenyl bismuth were added into a container, stirred at 50° C. for 4 h, and then placed at 50° C. for 24 h to obtain solution A; Step 2, placing the container containing solution A in a vacuum dryer, vacuumizing at room temperature, adding 7.5 g of 2,4-toluene diisocyanate and 3.8 g of hexamethylene diisocyanate, and stirring for 30 min to obtain solution B; Step 3: Pour solution B into a polytetrafluoroethylene mold, let it stand, evacuate at room temperature, and cure at 50° C. for 7 days to obtain the product.

8. A BGAP-PEG400 polyurethane elastic material, characterized in that: The BGAP-PEG400 polyurethane elastic material is prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the BGAP-PEG400 polyurethane elastic material prepared by the method for preparing the BGAP-PEG400 polyurethane elastic material according to any one of claims 1 to 7 in preparing a composite solid propellant.

10. Use of the BGAP-PEG400 polyurethane elastic material according to claim 8 for preparing composite solid propellant.

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