Photo-thermal synergistic self-repairing material for space micro-fragment protection and preparation method of photo-thermal synergistic self-repairing material

Abstract

The invention belongs to the technical field of functional materials, and relates to a photo-thermal synergistic self-repairing material for space tiny fragment protection and a preparation method of the photo-thermal synergistic self-repairing material. Through reversible covalent bonds in the self-repairing material, rapid repairing of space tiny fragment damage is realized. A traditional photo-initiation intrinsic self-repairing functional group anthracene graft and a traditional thermoplastic polymer material are compounded with photothermal effect components such as gold nanoparticles, and a photothermal effect is generated under an ultraviolet radiation condition in a space environment, so that a thermoplastic polymer is subjected to reversible phase change; the thermoplastic polymer material can be rapidly self-repaired in damage such as pits and cracks caused by high-speed impact of space tiny fragments, meanwhile, the grafted photo-initiation self-repairing functional groups can further penetrate into the chains to be subjected to cross-linking reinforcement repairing, repairing of the material is improved through double-synergistic self-repairing, and the requirement for on-orbit protection of space tiny fragment damage is met.

Description

Technical Field

[0001] This invention belongs to the field of functional materials technology and relates to a photothermal synergistic self-healing material for the protection of space micro-fragments and its preparation method. Background Technology

[0002] Space debris impacts on spacecraft surfaces generate a large number of ejecta fragments. These fragments can accumulate through secondary collisions, producing even more tiny space debris (1-1000 μm), with fragments smaller than 1 μm being countless, resulting in an enormous number in Earth orbit. The long-term cumulative impacts on operational spacecraft cannot be ignored. Hypervelocity impacts pose a serious threat to spacecraft operation. Impacts can cause erosion of critical components such as spacecraft surface materials, thermal control equipment, various sensors, solar panels, and especially optical equipment, damaging their performance and leading to complete failure. Recently, the solar panels on my country's space station have also been affected by space debris impacts, resulting in a continuous decline in performance. Therefore, the cumulative impacts of tiny space debris have a serious impact on spacecraft materials and systems, becoming a significant space environmental factor restricting the development of long-life, high-reliability spacecraft.

[0003] With the development of aerospace technology, higher demands are being placed on the long lifespan and high reliability of spacecraft. As detection technology continues to improve, various countries have gradually detected and recognized the hazards posed by micron-sized debris to spacecraft. Therefore, countries are paying increasing attention to the protection against micro-debris. Domestically and internationally, protection against large and medium-sized space debris is mainly achieved through Whipple protective structures, high-strength composite materials, or mesh protective screens. However, these methods have drawbacks such as excessive weight and complex structures. Furthermore, there is limited research on the protection against micro-debris, which is no longer sufficient to meet the needs of spacecraft space debris protection.

[0004] Therefore, the problem of on-orbit protection against micro-fragments urgently needs to be solved. With the development of smart materials, self-healing materials, as a novel type of smart structural functional material, mimic the principle of damage healing in living organisms. When a material is damaged, it mainly relies on its own internal resources to repair the damage. Self-healing can occur spontaneously after the material is damaged, or it can be induced by external stimuli such as light and heat. Intrinsic self-healing materials mainly achieve this through the molecular structure of reversible chemical reactions inherent in the polymer material itself, or through the diffusion of macromolecules. During the repair process, self-healing is achieved through external energy and stimuli such as mechanical force, light, heat, and pH changes, or it can achieve self-healing without any external conditions.

[0005] Self-healing materials offer a novel approach to protecting spacecraft from micro-fragment damage by enabling the self-healing of microcracks. Utilizing self-healing composite materials for on-orbit self-repair of micro-fragment damage can protect critical spacecraft components from impacts by sub-millimeter-sized, ultra-high-speed micro-fragments. Major spacefaring nations have begun research into space micro-fragment protection methods and materials based on self-healing materials, highlighting their immense potential and application value. Therefore, it is necessary to move beyond single-type self-healing methods and develop dual-synergistic self-healing material systems, leveraging the space's photothermal environment as repair energy. This will allow for the development of highly efficient biomimetic self-healing materials that meet the adaptability requirements of the space environment, fulfilling my country's space micro-fragment protection needs and ensuring the safe on-orbit operation of spacecraft. Summary of the Invention

[0006] This invention proposes a photothermal synergistic self-healing material for the protection of space micro-debris and its preparation method. The self-healing material described in this invention possesses the ability to rapidly repair damage from space micro-debris under the photothermal environment of space, effectively solving the problem of on-orbit protection against space micro-debris damage.

[0007] The technical solution adopted in this invention is as follows: A photothermal synergistic self-healing material for space debris protection grafted with anthracene, a traditional photo-initiated intrinsic self-healing functional group, is developed. This material is grafted onto traditional thermoplastic polymers (polyurethane resin PU, polyacrylic acid resin PAA). Through the inclusion of photothermal effect components such as gold nanoparticles (Au NPs), a photothermal effect is generated under ultraviolet irradiation in a space environment, causing a reversible phase transition in the thermoplastic polymer. This enables rapid self-repair of craters and cracks caused by high-speed impacts from space debris. Simultaneously, the grafted photo-initiated self-healing functional groups can further penetrate and cross-link between chains, strengthening the repair process. This dual synergistic self-healing effect enhances the material's repair capabilities, meeting the requirements for on-orbit protection against space debris damage and ensuring the normal on-orbit operation of spacecraft. The synthesis route of this novel photothermal synergistic self-healing polymer-based composite material is as follows:

[0008] The technical solution of this invention is: A photothermal synergistic self-healing material for the protection of space micro-fragments, the raw materials of which include 1-hydroxybenzotriazole (HOBt), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCl), polyacrylic acid, dichloromethane (DCM), anthracene-9-ylmethylamine, triethylamine, and N,N-dimethylacetamide (DMAc). A method for preparing a photothermal synergistic self-healing material for protection against space debris, the method comprising the following steps: The first step is to mix polyacrylic acid and dichloromethane to obtain a polyacrylic acid solution in dichloromethane; In the second step, 1-hydroxybenzotriazole (HOBt) and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCl) were added to the polyacrylic acid dichloromethane solution obtained in the first step. The mixture was stirred under ice-water bath conditions, and anthracene-9-ylmethylamine and triethylamine were added. The mixture was stirred at room temperature to obtain mixture A. The third step is to wash the mixture A obtained in the second step with a saturated NaHCO3 aqueous solution, and then wash it with saturated saline solution to obtain mixture B. Fourth step: Add anhydrous sodium sulfate to mixture B obtained in the third step, dry and filter to remove anhydrous sodium sulfate, remove organic solvent using a rotary evaporator to obtain solid; Fifth step: Add dichloromethane to the solid obtained in the fourth step until it is just completely dissolved, then add n-hexane, precipitate the solid, filter and collect it to obtain the raw material for the self-healing material; The sixth step involves dissolving the self-healing material raw material obtained in the fifth step in N,N-dimethylacetamide (DMAc), stirring until homogeneous to obtain a slightly viscous solution, and then drop-coating the slightly viscous solution onto a clean ITO glass. After uniform coating, the solution is placed in an oven to dry, resulting in a photothermal synergistic self-healing material film for the protection of space micro-fragments.

[0009] In the first step, the mass ratio of polyacrylic acid to dichloromethane is 5:1; In the second step, the mass ratio of 1-hydroxybenzotriazole (HOBt): 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCl): dichloromethane (DCM) solution of polyacrylic acid is 2:4:1; the mixture is stirred in an ice-water bath for 30 min, and then mixed with anthracene-9-ylmethylamine and triethylamine in a mass ratio of 1:3:7 and stirred at room temperature for another 5 h. In the sixth step, the mass ratio of the self-healing material raw material to N,N-dimethylacetamide (DMAc) is 1:6.

[0010] Beneficial effects This invention relates to a photothermal synergistic self-healing material for space debris protection and its preparation method. Based on intrinsic biomimetic self-healing materials, it utilizes external energy and stimulation from space light and heat to achieve rapid repair of space debris damage through reversible covalent bonds within the self-healing material. The invention involves grafting anthracene, a traditional photo-initiated intrinsic self-healing functional group, onto traditional thermoplastic polymer materials (polyurethane resin PU, polyacrylic acid resin PAA). By incorporating photothermal effect components such as composite gold nanoparticles (Au NPs), a photothermal effect is generated under ultraviolet irradiation in a space environment, causing a reversible phase transition in the thermoplastic polymer. This enables rapid self-repair of craters and cracks caused by high-speed impacts of space debris. Simultaneously, the grafted photo-initiated self-healing functional groups can further penetrate into the inter-chain crosslinking to enhance repair, achieving a dual synergistic self-healing effect to improve the material's repair capabilities and meet the requirements for on-orbit protection against space debris damage. The advantages of this invention are: by grafting the traditional photo-initiated intrinsic self-healing functional group anthracene onto traditional thermoplastic polymer materials, photonic repair function is achieved, and thermal self-repair is achieved through photothermal effect components such as composite gold nanoparticles (Au NPs). Thus, by utilizing the special photothermal environment of space, photothermal synergistic self-repair function is achieved, which meets the requirements for rapid on-orbit self-repair of space micro-fragment damage. Attached Figure Description

[0011] Figure 1 A schematic diagram of the repair mechanism of polyacrylic acid resin photothermal synergistic self-healing material; Figure 2 This is a schematic diagram of the original morphology of the thin film. Figure 3 This is a schematic diagram of the morphology of the film after cutting; Figure 4 This is a schematic diagram of the film morphology after 10 minutes of repair under heating conditions only; Figure 5 This is a schematic diagram of the film morphology after 10 minutes of repair under light-only conditions. Figure 6 This is a schematic diagram of the film morphology after 10 minutes of repair under heating and light conditions. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of the present invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0013] The first step involved determining the preparation scheme for photothermal synergistic self-healing materials based on the synthesis route for such materials used in the protection of space micro-fragmentation. The main materials used in the preparation included 1-hydroxybenzotriazole (HOBt), 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCl), polyacrylic acid, dichloromethane (DCM) solution, anthracene-9-ylmethylamine, triethylamine, anhydrous sodium sulfate, hexane, and N,N-dimethylacetamide (DMAc).

[0014] In the second step, 486 mg of 3.6 mmol of 1-hydroxybenzotriazole (HOBt) and 864 mg of 4.5 mmol of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDCl) were added to a solution of 216 mg of polyacrylic acid in dichloromethane (DCM), and the mixture was stirred in an ice-water bath for 30 minutes. Then, 3 mmol of 621 mg of anthracene-9-ylmethylamine and 6 mL of triethylamine were added, and the mixture was stirred at room temperature for another 5 hours. After the reaction was complete, the reaction solution was washed three times with 30 mL of saturated NaHCO3 aqueous solution, and then three times with 30 mL of saturated saline solution. Anhydrous sodium sulfate was added for drying, and the anhydrous sodium sulfate was removed by filtration. The organic solvent was removed using a rotary evaporator. Dichloromethane was added to the resulting solid until it was just completely dissolved, then n-hexane was added, and the precipitated solid was collected by filtration. This solid is the raw material for the self-healing material.

[0015] The third step involves preparing the self-healing material raw material. 270 mg of the raw material was weighed and dissolved in 1.8 mL of dichloromethane (DCM), and stirred until a slightly viscous solution was obtained. The solution was then drop-coated onto a clean ITO glass plate measuring 6 cm × 6 cm. After even coating, the plate was placed in an oven and dried at 60°C for 6 hours to obtain a photothermal synergistic self-healing film sample with a thickness of approximately 40 μm. This yields the self-healing material film.

[0016] By inducing a photothermal effect under ultraviolet irradiation in a space environment, self-healing material films undergo a reversible phase transition in thermoplastic polymers. This enables rapid self-repair of damage such as craters and cracks caused by high-speed impacts from tiny debris in space. Simultaneously, the grafted photo-initiated self-healing functional groups further enhance the repair through inter-chain cross-linking, achieving a dual synergistic self-healing effect that improves the material's overall repair capabilities. The repair mechanism based on polyacrylic acid resin materials is as follows... Figure 1 As shown. The self-healing performance of the three prepared self-healing material films was tested by scratching, as shown... Figure 2-6 As shown, when the repair conditions are limited to 365 nm ultraviolet light irradiation or 100 °C heating, the film is partially repaired but not completely repaired. After being simultaneously heated at 100 °C and irradiated with 365 nm ultraviolet light for 10 minutes, the fracture point of the film is almost invisible, achieving damage repair.

[0017] The accompanying drawings and embodiments described herein are only for explaining the technical solutions of the present invention and are not intended to limit the present invention. Those skilled in the art should understand this. Furthermore, the technical features involved in the various embodiments of the present invention described above can be combined with each other as long as they do not conflict with each other, without departing from the spirit of the present invention. They should all be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A photothermal synergistic self-healing material for the protection of space micro-fragments, characterized in that: The raw materials for this self-healing material include 1-hydroxybenzotriazole, 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride, polyacrylic acid, dichloromethane, anthracene-9-ylmethylamine, triethylamine, and N,N-dimethylacetamide.

2. A method for preparing a photothermal synergistic self-healing material for the protection of space micro-fragments, characterized in that... The steps of this method include: The first step is to mix polyacrylic acid and dichloromethane to obtain a polyacrylic acid solution in dichloromethane; In the second step, 1-hydroxybenzotriazole and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride were added to the dichloromethane solution of polyacrylic acid obtained in the first step, and stirred in an ice-water bath to obtain a mixture. Then, anthracene-9-ylmethylamine and triethylamine were added and stirred at room temperature to obtain mixture A. The third step is to wash the mixture A obtained in the second step with a saturated NaHCO3 aqueous solution, and then wash it with saturated saline solution to obtain mixture B. Fourth step: Add anhydrous sodium sulfate to mixture B obtained in the third step, dry and filter to remove anhydrous sodium sulfate, remove organic solvent using a rotary evaporator to obtain solid; Fifth step: Add dichloromethane to the solid obtained in the fourth step until it is just completely dissolved, then add n-hexane, precipitate the solid, filter and collect it to obtain the raw material for the self-healing material.

3. The method for preparing a photothermal synergistic self-healing material for the protection of space micro-fragments according to claim 2, characterized in that: In the first step, the mass ratio of polyacrylic acid to dichloromethane is 5:

1.

4. The method for preparing a photothermal synergistic self-healing material for the protection of space micro-fragments according to claim 2, characterized in that: In the second step, the mass ratio of 1-hydroxybenzotriazole: 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride: polyacrylic acid in dichloromethane solution is 2:4:

1.

5. The method for preparing a photothermal synergistic self-healing material for the protection of space micro-fragments according to claim 2, characterized in that: In step two, the mixture is stirred in an ice-water bath for 30 minutes.

6. The method for preparing a photothermal synergistic self-healing material for the protection of space micro-fragmentation according to claim 2, characterized in that: In the second step, the mass ratio of the mixture to anthracene-9-ylmethylamine and triethylamine is 1:3:

7.

7. The method for preparing a photothermal synergistic self-healing material for the protection of space micro-fragments according to claim 2, characterized in that: In the second step, the mixture is stirred at room temperature for 5 hours.

8. The method for preparing a photothermal synergistic self-healing material for the protection of space micro-fragments according to claim 2, characterized in that: The self-healing material raw material obtained in step 5 is dissolved in N,N-dimethylacetamide and stirred evenly to obtain a slightly viscous solution. The slightly viscous solution is drop-coated onto a clean ITO glass, and after being evenly coated, it is placed in an oven to dry, thus obtaining a photothermal synergistic self-healing material film for the protection of space micro-fragments.

9. A method for preparing a photothermal synergistic self-healing material for the protection of space micro-fragmentation according to claim 8, characterized in that: The mass ratio of the self-healing material raw material to N,N-dimethylacetamide is 1:6.

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