Self-repairing HTPB composite solid propellant based on dynamic hydrogen bond and preparation method thereof

Abstract

This invention relates to the field of solid propellant technology and discloses a self-healing HTPB composite solid propellant based on dynamic hydrogen bonds. It comprises the following raw materials in parts by weight: 10-30 parts self-healing binder, 0.5-3 parts curing agent, 0.1-0.5 parts curing catalyst, 5-30 parts fuel, 50-70 parts oxidant, 1-10 parts plasticizer, and 0.1-0.5 parts combustion rate catalyst. The self-healing binder is composed of HTPB and ureidopyrimidinone-modified aminopropylene glycol in a mass ratio of 4:1. This invention, by adding a segment component containing multiple hydrogen bonds to the binder, enables the prepared HTPB composite solid propellant to possess a self-healing effect. It can autonomously heal micro-damage generated in the system, reducing propellant failure and malfunction rate caused by damage, and ensuring the safe and stable operation of hydroxyl-butyl solid propellants.

Description

Technical Field

[0001] This invention relates to the field of solid propellant technology, specifically to a self-healing HTPB composite solid propellant based on dynamic hydrogen bonds and its preparation method. Background Technology

[0002] Solid propellants are viscoelastic materials primarily composed of binders and high-energy particles that are then cured. They provide efficient and rapid propulsion for a wide range of critical equipment, including gas generators, aero engines, and rocket boosters. Hydroxybutadiene-terminated polybutadiene (HTPB) solid propellants are a type of propellant using hydroxyl-terminated polybutadiene (HTPB) as a binder. They offer advantages such as wide applicability, excellent overall performance, a wide adjustable burning rate range, and relatively low cost, making them one of the mainstream solid propellants currently available.

[0003] However, current hydroxyl-butyl solid propellants, even after curing, still suffer from micro-damage under external temperature changes, alternating wet and dry conditions, and stress stimulation. This damage can easily lead to a decline in the propellant's mechanical properties, increase the risk of hotspot concentration during combustion, and cause explosions. By endowing propellants with self-healing properties, they can autonomously repair and heal their own defects when damage occurs, effectively improving the safety and stability of the propellant during service and reducing the incidence of failures and malfunctions. Therefore, this research has significant importance and value. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a self-healing HTPB composite solid propellant based on dynamic hydrogen bonds and its preparation method. After the propellant is cured, ureidopyrimidinone molecules can form quadruple dynamic hydrogen bonds, which can autonomously associate at the damage site, thereby providing the propellant with good self-healing properties. It can repair microcracks and other small damages in the system (autonomously repairing micro-damage with a width of 0-1 mm after being kept at 30℃ for 10-60 min), reducing the failure rate and ensuring the stability and safe service of the propellant system.

[0005] To achieve the above objectives, the technical solution of the present invention is: a self-healing HTPB composite solid propellant based on dynamic hydrogen bonds, comprising the following raw materials in parts by weight: 10-30 parts of self-healing adhesive, 0.5-3 parts of curing agent, 0.1-0.5 parts of curing catalyst, 5-30 parts of fuel, 50-70 parts of oxidant, 1-10 parts of plasticizer, and 0.1-0.5 parts of burning rate catalyst, wherein the self-healing adhesive is composed of HTPB and ureidopyrimidinone modified aminopropylene glycol in a mass ratio of 4:1.

[0006] Furthermore, the general structural formula of the ureidopyrimidinone-modified aminopropylene glycol is shown in formula (1):

[0007] Equation (1) In formula (1), R is an isocyanate molecule containing difunctionality.

[0008] Further, the curing agent is selected from one or more of toluene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), isophorone diisocyanate (IPDI), 1,5-naphthalene diisocyanate (NDI), hexamethylene diisocyanate (HDI), and dicyclohexylmethane diisocyanate (HMDI). The propellant bonding system is formed by the reaction of the isocyanate groups with active groups such as hydroxyl groups in the binder.

[0009] Furthermore, the curing catalyst is selected from one or more of 1,4-diazabicyclo[2,2,2]octane, dibutyltin laurylate, iron acetylacetonate, and triphenylbismuth (TPB), and is used to accelerate the reaction rate between the curing agent and the binder.

[0010] Furthermore, the fuel particle size is 1-100μm, and the fuel is selected from one or more of aluminum powder, magnesium powder, aluminum-magnesium alloy powder, aluminum-lithium alloy powder, and boron-magnesium alloy powder.

[0011] Furthermore, the oxidant has a particle size of 5-200 μm, and the oxidant is selected from one or more of ammonium perchlorate (AP), potassium perchlorate (KP), RDX, and octogen. The oxidant is used to improve combustion efficiency.

[0012] Furthermore, the plasticizer is dioctyl sebacate.

[0013] Furthermore, the combustion rate catalyst is selected from one or more of dioctyl azide (DOZ), catoxine, octylferrocene, and tert-butylferrocene.

[0014] Another technical solution of the present invention is: a method for preparing the self-healing HTPB composite solid propellant, comprising the following steps: (1) Add 10-30 parts of self-healing adhesive, 1-10 parts of plasticizer, and 0.1-0.5 parts of combustion rate catalyst to a container by weight, mix thoroughly, then add 5-30 parts of fuel and 50-70 parts of oxidant, and mix again until uniform; (2) Then add 0.5-3 parts of curing agent and 0.1-0.5 parts of curing catalyst to the mixture, mix evenly, and place in a vacuum environment to remove air bubbles for 30 min to obtain uncured self-healing propellant; (3) Then the uncured self-healing propellant is cast into the target cavity and kept at 30-70℃ for 0.5-7 days to obtain the self-healing HTPB composite solid propellant.

[0015] The beneficial effects of this invention are: (1) By adding a segment component containing multiple hydrogen bonds to the adhesive, the prepared HTPB composite solid propellant has a self-healing effect, which can self-heal the micro-damage generated in the system, reduce the propellant failure and failure rate caused by damage, and ensure the safe and stable operation of hydroxyl-butyl solid propellant.

[0016] (2) The hydrogen bond-based self-healing system of the present invention provides self-healing performance for HTPB composite solid propellant through the dissociation and association of hydrogen bonds when damage occurs. The hydrogen bond energy is low, so the triggering threshold for repair behavior is low. It can be carried out at or below the curing temperature without the need for external high temperature activation, thus avoiding the safety hazards caused by the increase in propellant activity due to excessively high repair temperature. The repair process is safe and reliable and has wide application value. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating the preparation process of the self-healing HTPB composite solid propellant based on dynamic hydrogen bonds, as described in this invention. Figure 2 It is the structural formula of ureidopyrimidinone-modified aminopropylene glycol in Example 1; Figure 3 These are SEM images of the self-healing HTPB composite solid propellant prepared in Example 1 before and after repair; Figure 4 It is the structural formula of ureidopyrimidinone-modified aminopropylene glycol in Example 2; Figure 5 These are SEM images of the self-healing HTPB composite solid propellant prepared in Example 2 before and after repair; Figure 6 It is the structural formula of ureidopyrimidinone-modified aminopropylene glycol in Example 3; Figure 7 These are SEM images of the self-healing HTPB composite solid propellant prepared in Example 3 before and after repair; Figure 8 This is a flowchart illustrating the preparation process of the HTPB composite solid propellant in Comparative Example 1. Figure 9 These are optical photographs of the HTPB composite solid propellant prepared in Comparative Example 1 before and after damage. Detailed Implementation

[0018] Example 1:

[0019] A method for preparing a self-healing HTPB composite solid propellant based on dynamic hydrogen bonds includes the following steps: (1) Weigh each raw material according to the weight parts, weigh 24 parts of HTPB prepolymer with a molecular weight of approximately 3000 Da, 6 parts of ureidopyrimidinone modified aminopropylene glycol, 5 parts of plasticizer dioctyl sebacate and 0.1 parts of octylferrocene and put them into a volume container, mix them evenly, wherein the structure of ureidopyrimidinone modified aminopropylene glycol is as follows Figure 2 As shown; (2) Then add 20 parts of aluminum powder with a particle size of about 100 μm and 60 parts of AP with a particle size of about 100 μm to the above mixture and mix evenly; (3) Continue to add 2 parts of IPDI curing agent and 0.1 parts of dibutyltin laurate, mix evenly, and place in a vacuum environment to remove air bubbles for 30 min to obtain uncured HTPB composite propellant; (4) Cast the uncured HTPB composite propellant into the target cavity and keep it at 40°C for 5 days to obtain the self-healing HTPB composite solid propellant.

[0020] A 1 mm wide scratch was introduced onto the surface of the self-healing HTPB composite solid propellant. After standing at room temperature for 60 minutes, the scratch essentially disappeared, demonstrating the self-healing effect. Figure 3 As shown.

[0021] Example 2:

[0022] A method for preparing a self-healing HTPB composite solid propellant based on dynamic hydrogen bonds includes the following steps: (1) Weigh each raw material according to the weight parts, weigh 24 parts of HTPB prepolymer with a molecular weight of approximately 4000 Da, 6 parts of ureidopyrimidinone modified aminopropylene glycol, 5 parts of plasticizer dioctyl sebacate and 0.1 parts of octylferrocene and put them into a volume container, mix them evenly, wherein the structure of ureidopyrimidinone modified aminopropylene glycol is as follows Figure 4 As shown; (2) Then add 20 parts of aluminum powder with a particle size of about 100 μm and 60 parts of AP with a particle size of about 100 μm to the above mixture and mix evenly; (3) Continue to add 2 parts of HDI curing agent and 0.1 parts of dibutyltin laurate, mix evenly, and place in a vacuum environment to remove air bubbles for 30 min to obtain uncured HTPB composite propellant; (4) Cast the uncured HTPB composite propellant into the target cavity and keep it at 40°C for 5 days to obtain the self-healing HTPB composite solid propellant.

[0023] A 500 μm wide scratch was introduced onto the surface of the self-healing HTPB composite solid propellant. After standing at room temperature for 30 minutes, the scratch essentially disappeared, demonstrating the self-healing effect. Figure 5 As shown.

[0024] Example 3:

[0025] A method for preparing a self-healing HTPB composite solid propellant based on dynamic hydrogen bonds includes the following steps: (1) Weigh each raw material according to the weight parts, weigh 24 parts of HTPB prepolymer with a molecular weight of approximately 4000 Da, 6 parts of ureidopyrimidinone modified aminopropylene glycol, 5 parts of plasticizer dioctyl sebacate and 0.1 parts of octylferrocene and put them into a volume container, mix them evenly, wherein the structure of ureidopyrimidinone modified aminopropylene glycol is as follows Figure 6 As shown; (2) Then add 20 parts of aluminum powder with a particle size of about 100 μm and 60 parts of AP with a particle size of about 100 μm to the above mixture and mix evenly; (3) Continue to add 2 parts of TDI curing agent and 0.1 parts of dibutyltin laurate, mix evenly, and place in a vacuum environment to remove air bubbles for 30 min to obtain uncured HTPB composite propellant; (4) The above-mentioned uncured HTPB composite propellant is cast into the target cavity and kept at 40°C for 2 days to obtain the self-healing HTPB composite solid propellant.

[0026] A 100 μm wide scratch was introduced onto the surface of a self-healing HTPB composite solid propellant. After standing at room temperature for 10 minutes, the scratch essentially disappeared, demonstrating the self-healing effect. Figure 7 As shown.

[0027] Comparative Example 1: A method for preparing an HTPB composite solid propellant includes the following steps: (1) Weigh each raw material according to the weight parts, weigh 30 parts of HTPB prepolymer with a molecular weight of about 3000 Da, 5 parts of plasticizer dioctyl sebacate and 0.1 parts of octyl ferrocene into an appropriate volume container and mix them evenly; (2) Then add 20 parts of aluminum powder with a particle size of about 100 μm and 60 parts of AP with a particle size of about 100 μm to the above mixture and mix evenly; (3) Continue to add 2 parts of IPDI curing agent and 0.1 parts of dibutyltin laurate, mix evenly, and place in a vacuum environment to remove air bubbles for 30 min to obtain uncured HTPB composite propellant; (4) The above-mentioned uncured HTPB propellant is cast into the target cavity and kept at 40°C for 5 days to obtain HTPB composite solid propellant.

[0028] A 1 mm wide scratch was introduced onto the surface of the HTPB composite solid propellant. After standing at room temperature for 60 minutes, the scratch remained essentially unchanged, showing no obvious self-healing effect. Optical photographs are shown below. Figure 9 As shown.

[0029] While the present invention has described the preferred embodiments and comparative examples above, these embodiments should not be construed as limiting the scope of protection of the present invention. Those skilled in the art should understand that the embodiments and comparative examples described herein are merely for the purpose of aiding in understanding the essence of the present invention. Therefore, any other modifications or improvements made by those skilled in the art based on the concept of the present invention still fall within the scope of protection of the present invention.

Claims

1. A self-healing HTPB composite solid propellant based on dynamic hydrogen bonds, characterized in that, It is composed of the following raw materials in parts by weight: 10-30 parts self-healing adhesive, 0.5-3 parts curing agent, 0.1-0.5 parts curing catalyst, 5-30 parts fuel, 50-70 parts oxidant, 1-10 parts plasticizer, and 0.1-0.5 parts combustion rate catalyst. The self-healing adhesive is composed of HTPB and ureidopyrimidinone modified aminopropylene glycol in a mass ratio of 4:

1.

2. The self-healing HTPB composite solid propellant based on dynamic hydrogen bonds according to claim 1, characterized in that, The general structural formula of the ureidopyrimidinone-modified aminopropylene glycol is shown in formula (1): Equation (1) In formula (1), R is an isocyanate molecule containing difunctionality.

3. The self-healing HTPB composite solid propellant based on dynamic hydrogen bonds according to claim 1, characterized in that: The curing agent is selected from one or more of TDI, MDI, IPDI, NDI, HDI and HMDI.

4. The self-healing HTPB composite solid propellant based on dynamic hydrogen bonds according to claim 1, characterized in that: The curing catalyst is selected from one or more of 1,4-diazabicyclo[2,2,2]octane, dibutyltin laurylate, iron acetylacetone, and triphenylbismuth.

5. The self-healing HTPB composite solid propellant based on dynamic hydrogen bonds according to claim 1, characterized in that: The fuel particle size is 1-100μm, and the fuel is selected from one or more of aluminum powder, magnesium powder, aluminum-magnesium alloy powder, aluminum-lithium alloy powder, and boron-magnesium alloy powder.

6. The self-healing HTPB composite solid propellant based on dynamic hydrogen bonds according to claim 1, characterized in that: The oxidant has a particle size of 5-200 μm and is selected from one or more of AP, KP, RDX and Octogen.

7. The self-healing HTPB composite solid propellant based on dynamic hydrogen bonds according to claim 1, characterized in that: The plasticizer is dioctyl sebacate.

8. The self-healing HTPB composite solid propellant based on dynamic hydrogen bonds according to claim 1, characterized in that: The combustion rate catalyst is selected from one or more of dioctyl azide, catoxine, octyl ferrocene, and tert-butyl ferrocene.

9. The method for preparing the self-healing HTPB composite solid propellant as described in any one of claims 1-8, characterized in that, Includes the following steps: (1) Add 10-30 parts of self-healing adhesive, 1-10 parts of plasticizer, and 0.1-0.5 parts of combustion rate catalyst to a container by weight, mix thoroughly, then add 5-30 parts of fuel and 50-70 parts of oxidant, and mix again until uniform; (2) Then add 0.5-3 parts of curing agent and 0.1-0.5 parts of curing catalyst to the mixture, mix evenly, and place in a vacuum environment to remove air bubbles for 30 min to obtain uncured self-healing propellant; (3) Then the uncured self-healing propellant is cast into the target cavity and kept at 30-70℃ for 0.5-7 days to obtain the self-healing HTPB composite solid propellant.

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