Compound bonding agent suitable for thermoplastic elastomer propellant, application and thermoplastic elastomer solid propellant

Abstract

The invention discloses a compound bonding agent suitable for a thermoplastic elastomer propellant, an application of the compound bonding agent and a thermoplastic elastomer solid propellant. The compound bonding agent provided by the invention comprises a polyamine boron trifluoride polymer and 2-ureido-4 [1H] pyrimidone isocyanate. By adopting a compound bonding agent of the polyamine boron trifluoride polymer and the-ureido-4 [1H] pyrimidone isocyanate, the interface interaction between a thermoplastic adhesive and a solid filler is improved, and the mechanical property of the thermoplastic elastomer propellant is improved through coordination and multiple hydrogen-bond interaction.

Description

Technical Field

[0001] The present invention relates to the technical field of solid propellants, and in particular, to a compound bonding agent applicable to thermoplastic elastomer propellants, an application thereof, and a thermoplastic elastomer solid propellant. Background Art

[0002] Solid propellants can be divided into thermosetting composite solid propellants and thermoplastic composite solid propellants according to the curing behavior of the adhesives used. Traditional thermosetting composite solid propellants have defects such as short pot life of the slurry, difficult recycling and treatment of waste propellant, and poor batch-to-batch repeatability because they need to be cured to form a chemical crosslinking network during the preparation process; while thermoplastic composite solid propellants use thermoplastic elastomers (TPEs) that are easy to process and form as the binder matrix, and do not need to be cured during the preparation process, and can be processed and formed repeatedly, which is expected to solve the problems existing in the above thermosetting propellants.

[0003] However, it is undeniable that the poor mechanical properties of thermoplastic elastomer propellants greatly limit their application and development. In the field of solid propellants, the mechanical properties of propellants are often improved by adding bonding agents. However, different from the general bonding mechanism, thermoplastic elastomer propellants are not suitable for the way of forming covalent bonds by chemical reaction between the bonding agent and the binder. Therefore, boron trifluoride triethanolamine complex, aziridine phosphine oxide, neutral macromolecular bonding agents, etc., which are commonly used in hydroxy-terminated polybutadiene, high-energy and other solid propellants, are difficult to be applied in thermoplastic elastomers. In order to improve the dehumidification phenomenon in thermoplastic propellants and improve the mechanical properties of propellants, it is urgent to develop a bonding agent suitable for thermoplastic elastomer propellants. Summary of the Invention

[0004] The purpose of the present invention is to provide a compound bonding agent applicable to thermoplastic elastomer propellants, an application thereof, and a thermoplastic elastomer solid propellant to overcome the defects existing in the above-mentioned prior art.

[0005] The present invention solves its technical problems by adopting the following technical solutions.

[0006] An embodiment of the present invention provides a compound bonding agent applicable to thermoplastic elastomer propellants, and the compound bonding agent includes a polyamine boron trifluoride polymer and 2-ureido-4[1H]pyrimidinone isocyanate.

[0007] The present invention also provides an application of the compound bonding agent applicable to thermoplastic elastomer propellants in solid propellants.

[0008] The present invention also provides a thermoplastic elastomer solid propellant, and the solid propellant includes the above compound bonding agent and other components.

[0009] The present invention has the following beneficial effects:

[0010] The present invention provides a compound bonding agent applicable to thermoplastic elastomer propellants, its application, and a thermoplastic elastomer solid propellant. The compound bonding agent of polyamine boron trifluoride polymer and 2-ureido-4[1H]pyrimidinone isocyanate provided by the present invention is used in thermoplastic elastomer propellants, which can improve the dehumidification phenomenon of AP in thermoplastic elastomer propellants and increase the tensile strength and elongation at break of the propellant at normal and low temperatures. The polyamine-BF in the compound bonding agent 3 while retaining the original high polarity of the polyamine, also introduces BF 3 coordination, thereby improving the wetting effect of the bonding agent on AP. In addition, the UPy-NCO six-membered ring is rich in hydrogen bond donors and acceptors, which can form multiple hydrogen bonds with the binder, thus enhancing the bonding effect and improving the mechanical properties of the propellant. Specific embodiments

[0011] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Those not specified in the embodiments are carried out according to conventional conditions or conditions recommended by the manufacturer. The reagents or instruments not specified by the manufacturer are all conventional products that can be obtained through commercial purchase.

[0012] One objective of the present invention is to provide a compound bonding agent applicable to thermoplastic elastomer propellants and its preparation method. Another objective of the present invention is to provide the application of the compound bonding agent in the thermoplastic elastomer propellant system. In view of the fact that the existing bonding agent system is difficult to be applicable to thermoplastic elastomer propellants, the polyamine boron trifluoride polymer and 2-ureido-4[1H]pyrimidinone isocyanate are synthesized and compounded as a bonding agent for use in thermoplastic elastomer propellants, which greatly improves the dehumidification phenomenon of the propellants and significantly enhances the mechanical properties of the propellants at normal and low temperatures, and is of great significance to the engineering application of thermoplastic elastomer propellants.

[0013] The above objectives of the present invention are mainly achieved through the following technical solutions:

[0014] In the first aspect, an embodiment of the present invention provides a compound bonding agent applicable to thermoplastic elastomer propellants, and the compound bonding agent includes a polyamine boron trifluoride polymer and 2-ureido-4[1H]pyrimidinone isocyanate.

[0015] In some optional embodiments, the structural formula of the polyamine boron trifluoride polymer is shown as the following formula I:

[0016]

[0017] wherein, n is 10 to 4000.

[0018] In some alternative embodiments, the polyamine includes one or more of triethylenediamine, tetraethylenepentamine, or pentaethylenehexamine.

[0019] In some alternative embodiments, the structural formula of the 2-ureido-4[1H]pyrimidinone isocyanate is as shown in Formula II below:

[0020]

[0021] In some alternative embodiments, polyamine-BF 3 The preparation method includes: dissolving the polyamine in an appropriate amount of anhydrous tetrahydrofuran, slowly dropping the ethereal solution of boron trifluoride into the reaction system, stirring the reaction, and then obtaining the product by rotary evaporation to remove the excess volume.

[0022] Preferably, the stirring reaction conditions are ice bath with nitrogen passing through, and the stirring time is 1-2 hours.

[0023] Preferably, the molar ratio of the polyamine to boron trifluoride is 1:1.

[0024] In some alternative embodiments, the preparation method of UPy-NCO includes: putting an appropriate amount of UPy into a reaction vessel, adding an excess of isocyanate into the system in an anhydrous environment, carrying out condensation reflux, filtering to obtain a white solid after the reaction is completed, and washing three times with anhydrous n-hexane to remove the unreacted NCO to obtain the target product.

[0025] Preferably, the stirring reaction conditions are 60-90 °C, and the reaction time is 24 hours.

[0026] Preferably, the molar ratio of the so-called Upy to NCO is 8:1.

[0027] The present invention can achieve the preparation of polyamine-BF 3 with different molecular weights by adjusting different feeding ratios, and can achieve different mechanical properties of the thermoplastic elastomer propellant by regulating the mass ratio of polyamine-BF 3 and UPy-NCO. The preparation method of the polyamine-BF 3 / UPy-NCO compound bonding agent provided by the present invention is simple, the preparation conditions are mild, and the preparation efficiency is high.

[0028] Second, the embodiments of the present invention provide an application of a compound bonding agent suitable for a thermoplastic elastomer propellant in a solid propellant.

[0029] In some alternative embodiments, the percentage contents of the polyamine boron trifluoride polymer and the 2-ureido-4[1H]pyrimidinone isocyanate in the thermoplastic elastomer solid propellant are 0.01% - 0.1% and 0.01% - 0.4% respectively.

[0030] In a third aspect, an embodiment of the present invention provides a thermoplastic elastomer solid propellant, and the solid propellant includes the above-mentioned compound bonding agent and other components.

[0031] In some alternative embodiments, the other components include: a thermoplastic elastomer binder, a plasticizer, an oxidizer, a metal fuel, and other functional aids.

[0032] In some alternative embodiments, the thermoplastic elastomer binder includes one or a combination of thermoplastic polyurethane (TPU), styrene-butadiene-styrene block copolymer (SBS), thermoplastic polyvinyl chloride (TPVC), ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylic acid copolymer (EMAA), and ethylene-methyl methacrylate copolymer (EMMA).

[0033] In some alternative embodiments, the plasticizer includes one or more of dioctyl sebacate (DOS), dioctyl phthalate (DOP), and tributyl citrate (TBC).

[0034] In some alternative embodiments, the oxidizer includes ammonium perchlorate or potassium perchlorate.

[0035] In some alternative embodiments, the metal fuel includes one or a combination of aluminum powder, aluminum trihydride, and aluminum-lithium alloy.

[0036] In some alternative embodiments, the other functional aids include one or a combination of octyldicyclopentadienyliron, iron(III) oxide, aniline, and N,N-dimethylaniline.

[0037] In some alternative embodiments, the propellant includes components in the following mass fractions: thermoplastic elastomer binder: 5% - 8%; plasticizer: 5% - 8%; oxidizer: 65% - 70%; metal fuel: 15% - 18%; polyamine-BF 3 : 0.01% - 0.1%; UPy-NCO: 0.01% - 0.4%; other functional aids: 0.5% - 2%.

[0038] The present invention will be further described below in conjunction with embodiments.

[0039] In the following Examples 1 - 4, the specific preparation method of the polyamine-BF 3 / UPy-NCO compound bonding agent is as follows:

[0040] The synthesis route of polyamine-BF 3 is as follows:

[0041]

[0042] Dissolve triethylenediamine in an appropriate amount of anhydrous tetrahydrofuran, and then slowly drop an equimolar ratio of boron trifluoride ether solution into the reaction system. Pass nitrogen through the ice bath and stir the reaction for 1 - 2 h. Then remove the excess solvent by rotary evaporation and dry it in a vacuum oven at 40 °C for 6 - 10 h to obtain triethylenediamine - BF 3 .

[0043] The synthetic route of UPy - NCO is as follows:

[0044]

[0045] Put an appropriate amount of UPy into the reaction vessel, take an excess of isocyanate in an anhydrous environment and add it to the reaction vessel (the molar ratio of Upy to NCO is 8:1), carry out condensation reflux at 60 - 90 °C for 24 h. After the reaction is completed, filter to obtain a white solid, wash it three times with anhydrous n - hexane to remove the unreacted NCO, and dry it in an oven at 60 °C for 8 - 10 h to obtain UPy - NCO.

[0046] Example 1

[0047] Table 1 shows the composition (mass percentage) of the TPU - based thermoplastic elastomer propellant, where the polyamine - BF 3 has a weight - average molecular weight Mw of 1200. Except for the blank group, the total amount of the polyamine - BF 3 / UPy - NCO composite bonding agent is 0.1%.

[0048] Table 1

[0049]

[0050]

[0051] Table 2 shows the mechanical properties of the TPU - based thermoplastic elastomer propellant with different mass ratios of the polyamine - BF 3 / UPy - NCO composite bonding agent.

[0052] Table 2

[0053]

[0054] Example 2

[0055] Table 3 shows the composition (mass percentage) of the EEA - based thermoplastic elastomer propellant, where the polyamine - BF 3 has a weight - average molecular weight Mw of 1200. Except for the blank group, the total amount of the polyamine - BF 3 / UPy - NCO composite bonding agent is 0.1%.

[0056] Table 3

[0057]

[0058] Table 4 shows the mechanical properties of the EEA-based thermoplastic elastomer propellant with polyamine-BF 3 / UPy-NCO complex bonding agent at different mass ratios.

[0059] Table 4

[0060]

[0061] Example 3

[0062] Table 5 shows the composition (mass percentage) of the EEA-based thermoplastic elastomer propellant with different contents of the complex bonding agent, where the weight-average molecular weight Mw of polyamine-BF 3 is 1200.

[0063] Table 5

[0064]

[0065] Table 6 shows the mechanical properties of the EEA-based thermoplastic elastomer propellant with different contents of the complex bonding agent.

[0066] Table 6

[0067]

[0068] Example 4

[0069] Table 7 shows the mechanical properties of the EEA-based thermoplastic elastomer propellant containing polyamine-BF 3 (300, 1200, 4000, 10000), and the other components of the propellant are the same as those in the 9# formulation.

[0070] Table 7

[0071]

[0072] Comparative Examples 1 - 3

[0073] Table 8 shows the composition (mass percentage) of the TPU-based thermoplastic elastomer propellant.

[0074] Table 8

[0075]

[0076] Table 9 shows the mechanical properties of the TPU-based thermoplastic elastomer propellants numbered 19# - 21#.

[0077] Table 9

[0078]

[0079] As can be seen from the above results: Examples 1-4 above contain polyamine-BF 3 / UPy-NCO compound bonding agent in thermoplastic elastomer solid propellants, mechanical properties, and the dosage of polyamine-BF 3 / UPy-NCO in solid propellants and the molecular weight of polyamine-BF 3 It can be known that the polyamine-BF 3 / UPy-NCO compound bonding agent provided by the present invention can significantly improve the mechanical properties of thermoplastic elastomer propellants at normal and low temperatures and improve the dehumidification phenomenon. After adding the polyamine-BF 3 / UPy-NCO compound bonding agent, through the coordination effect of polyamine-BF 3 and the multiple hydrogen bond sites of UPy-NCO, the surface wettability of the bonding agent to ammonium perchlorate can be improved, and the interaction between the thermoplastic binder, the bonding agent, and the solid filler can be enhanced. It can be seen from the data in Examples 1-4 that only using 0.1% of the polyamine-BF 3 / UPy-NCO compound bonding agent can simultaneously improve the tensile strength and elongation at break of TPU-based and EEA-based thermoplastic elastomer propellants. Further, by controlling the mass ratio of polyamine-BF 3 to UPy-NCO, the molecular weight of polyamine-BF 3 and the total content of polyamine-BF 3 to UPy-NCO, the mechanical properties of the EEA-based thermoplastic elastomer propellant at normal and low temperatures can reach 0.66 MPa / 25.1% and 3.94 MPa / 20.8%. Compared with the blank group, the tensile strength is increased by more than 30%, and the elongation at break is increased by more than 150%.

[0080] In Comparative Examples 1-3, the compound bonding agent MAPO / T313 applicable to hydroxyl-terminated polybutadiene propellants was used in the thermoplastic propellants of the present invention, and its mechanical properties were poor, indicating that the MAPO / T313 compound bonding agent is not applicable to the thermoplastic propellants of the present invention. Using the polyamine-BF 3 / UPy-NCO compound bonding agent in the present invention can significantly improve the mechanical properties of the propellant.

[0081] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A compound bonding agent suitable for thermoplastic elastomer propellants, characterized in that: The composite bonding agent comprises polyamine boron trifluoride polymer and 2-urea-4[1H]pyrimidinone isocyanate.

2. The composite bonding agent according to claim 1, characterized in that: The structural formula of the polyamine boron trifluoride polymer is shown in the following formula I: Among them, n is 10 to 4000.

3. The composite bonding agent according to claim 2, characterized in that: The polyamine includes one or more of triethylenediamine, tetraethylenetriamine or pentaethylenetetramine.

4. The composite bonding agent according to claim 1, characterized in that: The structural formula of the 2-ureido-4[1H]pyrimidinone isocyanate is shown in Formula II below:

5. Use of the composite bonding agent according to any one of claims 1 to 4 in thermoplastic elastomer solid propellant.

6. The use according to claim 5, characterized in that: The percentage contents of the polyamine boron trifluoride polymer and the 2-urea-4[1H]pyrimidinone isocyanate in the thermoplastic elastomer solid propellant are 0.01% to 0.1% and 0.01% to 0.4% respectively.

7. A thermoplastic elastomer solid propellant, characterized in that: include: The composite bonding agent and other auxiliary agents according to any one of claims 1 to 4.

8. The thermoplastic elastomer solid propellant according to claim 7, characterized in that: The other additives include: thermoplastic elastomer adhesive, plasticizer, oxidant, metal fuel and other functional additives.

9. The thermoplastic elastomer solid propellant according to claim 8, characterized in that: The thermoplastic elastomer adhesive includes one or more of thermoplastic polyurethane (TPU), styrene-butadiene-styrene block copolymer (SBS), thermoplastic polyvinyl chloride (TPVC), ethylene-vinyl acetate copolymer (EVA), ethylene-methacrylic acid copolymer (EMAA), and ethylene-methyl methacrylate copolymer (EMMA); The plasticizer includes one or more of dioctyl sebacate (DOS), dioctyl phthalate (DOP), and tributyl citrate (TBC); The oxidant is ammonium perchlorate or potassium perchlorate; The metal fuel includes one or more of aluminum powder, aluminum hydride, and aluminum-lithium alloy; The other functional additives include one or more of octylferrocene, ferric oxide, aniline, and N,N-dimethylaniline.

10. The thermoplastic elastomer solid propellant according to claim 7, characterized in that: The propellant comprises the following components in mass fraction: thermoplastic elastomer adhesive: 5% to 8%; plasticizer: 5% to 8%; oxidant: 65% to 70%; metal fuel: 15% to 18%; polyamine-BF3: 0.01% to 0.1%; UPy-NCO: 0.01% to 0.4%; and other functional additives: 0.5% to 2%.

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