Surface-coated modified cooling agent and preparation method thereof
By modifying the surface of the cooling agent by organosilane to form a core-shell structure, the problems of low reaction activity and irregular morphology of the cooling agent are solved, and the mechanical properties and environmental adaptability of the solid propellant are significantly improved.
Patent Information
- Application Number
- CN202411975486.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2025-04-04
AI Technical Summary
The existing cooling agent materials have low reactivity and irregular morphology in solid propellants, resulting in insufficient mechanical properties of solid propellants, making it difficult to meet the needs of low-burning temperature solid propellants.
By using an organosilane material to coat and modify the surface of the cooling agent, a core-shell structure is formed, and the content of active groups such as amino groups and hydroxyl groups on the surface of the cooling agent is regulated, thereby enhancing the thermal stability and reactive activity of the material.
It effectively improves the reactivity and morphological regularity of the cooling agent, enhances the mechanical properties and environmental adaptability of the solid propellant, and is suitable for low-burning temperature solid propellants.
Smart Images
Figure CN119751184A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of solid propellants, and in particular to a surface-coated modified cooling agent and a preparation method thereof. Background Art
[0002] Gas generator is a special type of low combustion temperature solid propellant, which has the characteristics of low combustion temperature, "clean" gas, and large gas production. As a special power source, it has been widely used in missile starters, superchargers, gyroscopes, steering gears, gas turbine devices, liquid rocket turbine starters, and automobile airbags. In order to make the combustion temperature of the gas generator meet the operating temperature of the auxiliary power unit, a large amount of cooling agent is added to the gas generator formula. The cooling agent mainly decomposes and absorbs heat to reduce the combustion temperature of the gas generator. Common cooling agents include oxalic acid amine (AO), dihydroxyglyoxime (DHG) and ammonium sulfate (AS).
[0003] However, these commonly used cooling agent materials contain amino or hydroxyl groups with low reactivity, and are not easy to react with the isocyanate groups in the curing agent, which affects the curing effect of the gas generator, causing the solid propellant to dehumidify and have low mechanical properties. In addition, the morphology of cooling agent materials is mostly flaky, such as dihydroxyglyoxime, which is a white needle-shaped crystal. The irregular morphology makes the interface formed between it and the adhesive network easily damaged, which also leads to insufficient mechanical properties of the gas generator. In recent years, although some progress has been made in the sphericalization of cooling agents, it still cannot significantly improve the mechanical properties of gas generators. Therefore, it is urgent to explore new ways to regulate the reactivity of cooling agents, enhance the morphological regularity of cooling agents, and thus improve the mechanical properties and environmental adaptability of gas generators. Summary of the invention
[0004] In order to solve the above technical problems, the present invention discloses a surface-coated and modified cooling agent and a treatment method thereof. The present invention uses organic silane as a coating agent, and forms an inorganic shell structure on the surface of the cooling agent through the hydrolysis polymerization reaction of silane. The outer layer of silane can greatly reduce the sharp area of the cooling agent, enhance the thermal stability of the material, and control the content of active groups such as amino groups and hydroxyl groups on the surface of the cooling agent material through the ratio of single or multiple silanes, thereby controlling the reaction activity of the cooling agent material.
[0005] To achieve the purpose of the present invention, the present invention provides the following technical solutions: a surface-coated modified cooling agent, the cooling agent particles are coated with an organic silane material to form a core-shell structure, the core is the cooling agent particles, and the shell is the organic silane material;
[0006] The thickness of the shell is in the range of 50nm to 500nm, and the surface active groups of the surface-coated modified cooling agent include one or more of -NH2, -Cl, -SH, and vinyl.
[0007] Preferably, the cooling agent particles include one of dihydroxyglyoxime, ammonium sulfate and ammonium oxalate.
[0008] Preferably, the organosilane material includes one or more of tetraethyl orthosilicate, octadecyltrimethylsilane, γ-aminopropyltrimethoxysilane, vinyltriethoxysilane, mercaptotriethoxysilane and γ-chloropropyltrimethoxysilane.
[0009] A method for preparing a surface-coated modified cooling agent comprises the following steps:
[0010] Step 1: prepare a first solution and a second solution respectively;
[0011] The preparation method of the first solution comprises dispersing cooling agent particles into an ethanol solution and adjusting the pH value to 8 to 9 to obtain a first solution;
[0012] The preparation method of the second solution includes dispersing an organosilane material into an ethanol solution to obtain a second solution;
[0013] Step 2: adding the second solution to the first solution and reacting under the first condition;
[0014] Step three: After the reaction is completed under the first conditions, filter, wash, and dry to obtain a surface-coated modified cooling agent.
[0015] Preferably, the cooling agent material includes one of dihydroxyglyoxime, ammonium sulfate and ammonium oxalate.
[0016] Preferably, the mass concentration of the cooling agent material in the first solution is 0.1 g / mL to 2.0 g / mL.
[0017] Preferably, the organosilane material includes one or more of tetraethyl orthosilicate, octadecyltrimethylsilane, γ-aminopropyltrimethoxysilane, vinyltriethoxysilane, mercaptotriethoxysilane and γ-chloropropyltrimethoxysilane.
[0018] Preferably, the mass concentration of the organosilane material in the second solution is 0.005 mg / mL to 0.10 mg / mL.
[0019] Preferably, the first condition is stirring at 30° C. to 50° C. for 1 h to 6 h.
[0020] Beneficial effects of the above technical solution:
[0021] By using various types of silane materials to coat and modify the surface of the cooling agent, the types and contents of amino, hydroxyl and other groups on the surface of the cooling agent can be effectively adjusted, thereby controlling the reactivity of the cooling agent with the adhesive system and solving the problem of cooling agent dehumidification in solid propellants. At the same time, by introducing a silane coating layer, the shear force stability and thermal stability of the cooling agent material are effectively improved, and its adaptability in high load and complex environments is enhanced, which can be used to improve the mechanical properties of low combustion temperature solid propellants. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.
[0023] Figure 1 Schematic diagram of the surface-coated modified cooling agent provided by the present invention before and after coating and modification;
[0024] Figure 2 It is a SEM image of dihydroxyglyoxime in the prior art;
[0025] Figure 3 This is a SEM image of the surface-coated modified cooling agent provided by the present invention;
[0026] Figure 4 EDS of the surface-coated modified cooling agent provided in Example 1 of the present invention Figure 1 ;
[0027] Figure 5 EDS of the surface-coated modified cooling agent provided in Example 1 of the present invention Figure 2 ;
[0028] Figure 6 This is an infrared spectrum of the surface-coated modified cooling agent provided in Example 1 of the present invention. DETAILED DESCRIPTION
[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.
[0030] Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, and should not be construed as limiting the present invention.
[0031] Embodiment 1
[0032] Figure 1 The schematic diagram of the surface-coated modified cooling agent provided by the present invention before and after coating and modification is shown. The preparation method comprises the following steps:
[0033] Weigh 10 g of dihydroxyglyoxime (DHG) particles, preferably, SEM such as Figure 2 As shown, it was dispersed in 40 mL of ethanol solution; then 5 mL of ammonia solution was added and stirred at room temperature for 5 minutes to form a uniform suspension A (first solution).
[0034] Take 0.1 mL of tetraethyl orthosilicate and γ-aminopropyltrimethoxysilane in a mass ratio of 4:0, 3:1, 2:2, 1:3, and 4:0 and disperse them in 10 mL of ethanol solution. Ultrasonic treatment is performed for 10 minutes to uniformly disperse tetraethyl orthosilicate and γ-aminopropyltrimethoxysilane in the solvent to form solution B (second solution).
[0035] Solution B was added to solution A and reacted at 50°C for 3 h.
[0036] After the reaction was completed, the product was cooled to room temperature, filtered under reduced pressure, washed with ethanol three times and distilled water once, and then transferred to a drying oven. After vacuum drying at 50°C for 24 hours, a surface-coated modified cooling agent was obtained, which were marked as sample 1 to sample 5, respectively.
[0037] from Figure 2 SEM images of dihydroxyglyoxime raw materials and Figure 3 The SEM image of sample 2 shows that the surface of DHG that has not been surface treated is smooth, and the particles have more sharp edges and corners. The surface roughness of the particles of the surface-coated modified cooling agent sample 1 provided by the present invention is increased, and the angular areas are smooth.
[0038] The surface-coated modified cooling agent sample 2 was characterized by elemental analysis. Its main surface elements are composed of Si, N, etc. Figure 4 and Figure 5 EDS of surface-coated modified cooling agent Figure 1 and Figure 2 As shown, it is shown that after the surface treatment, the silane coating material chemically reacts with the surface layer of the cooling agent raw material, and an inorganic compound layer is formed on the surface of the cooling agent raw material dihydroxyglyoxime.
[0039] The functional group content of the surface-coated modified cooling agent was characterized by infrared spectroscopy. -1 The Si-O stretching vibration peak is normalized to 3377 cm-1 as the reference point. -1 The absorption peak intensity at , thus qualitatively determining the content of amino groups in the coating layer. Figure 6As shown in the infrared spectrum of the surface-coated modified cooling agent, the surface amino group content of the surface-coated modified cooling agent provided by the present invention is positively correlated with the γ-aminopropyltrimethoxysilane content, and the type and content of the surface functional groups of the cooling agent can be controlled by adjusting the type and ratio of silane.
[0040] Embodiment 2
[0041] (1) Weigh 10 g of ammonium sulfate (AS) particles and disperse them in 80 mL of ethanol solution; then add 5 mL of ammonia solution to adjust the pH value of the solution to a range of 8 to 9, and stir at room temperature for 5 min to form a uniform suspension A.
[0042] (2) 1 mg of octadecyltrimethylsilane, γ-chloropropyltrimethoxysilane, and mercaptotriethoxysilane were dispersed in 10 mL of ethanol solution in a ratio of 1:1:1, and ultrasonically treated for 10 min to uniformly disperse the silane reagent in the solvent to form solution B.
[0043] (3) Solution B was added to solution A and reacted at 30°C for 6 h.
[0044] (4) After the reaction is completed, the product is cooled to room temperature, filtered under reduced pressure, washed with ethanol three times and distilled water once, and then transferred to a drying oven. After vacuum drying at 50° C. for 24 h, a surface-coated modified cooling agent is obtained.
[0045] The performance of the surface-coated modified cooling agent of Example 2 was characterized. The thickness of the shell ranged from 200 nm to 250 nm. The surface of the coated modified cooling agent had -NH 2、 -SH active group.
[0046] Embodiment 3
[0047] (1) Weigh 10 g of ammonium oxalate (AO) particles and disperse them in 20 mL of toluene solution; then add 1 mL of ammonia solution to adjust the pH value of the solution to a range of 8 to 9, and stir at room temperature for 5 min to form a uniform suspension A.
[0048] (2) 0.1 mg of tetraethyl orthosilicate and vinyl triethoxysilane were dispersed in 10 mL of ethanol solution in a 1:1 ratio and ultrasonically treated for 10 min to uniformly disperse the silane reagent in the solvent to form solution B.
[0049] (3) Solution B was added to solution A and reacted at 50°C for 4 h.
[0050] (4) After the reaction is completed, the product is cooled to room temperature, filtered under reduced pressure, washed with ethanol three times and distilled water once, and then transferred to a drying oven. After vacuum drying at 50° C. for 24 h, a surface-coated modified cooling agent is obtained.
[0051] The performance of the surface-coated modified cooling agent of Example 3 was characterized. The thickness of the outer shell ranged from 350 nm to 400 nm, and the surface of the coated modified cooling agent had vinyl active groups.
[0052] Embodiment 4
[0053] (1) Weigh 10 g of ammonium oxalate (AO) particles and disperse them in 40 mL of toluene solution; then add 1 mL of ammonia solution to adjust the pH value of the solution to a range of 8 to 9, and stir at room temperature for 5 minutes to form a uniform suspension A.
[0054] (2) 0.08 mg of tetraethyl orthosilicate and mercaptotriethoxysilane were dispersed in 10 mL of ethanol solution in a ratio of 3:1, and ultrasonically treated for 10 min to uniformly disperse the silane reagent in the solvent to form solution B.
[0055] (3) Solution B was added to solution A and reacted at 50°C for 2 h.
[0056] (4) After the reaction is completed, the product is cooled to room temperature, filtered under reduced pressure, washed with ethanol three times and distilled water once, and then transferred to a drying oven. After vacuum drying at 50° C. for 24 h, a surface-coated modified cooling agent is obtained.
[0057] The performance of the surface-coated modified cooling agent of Example 4 was characterized. The thickness of the outer shell ranged from 150 nm to 180 nm, and the surface of the coated modified cooling agent had -SH active groups.
[0058] As can be seen from the above embodiments, the preparation method of the surface-coated cooling agent provided by the present invention controls the type and content of the surface functional groups of the surface-coated cooling agent by regulating the type and ratio of silane. The structure of the surface-coated cooling agent includes a core and a shell, wherein the core is a cooling agent material, and the shell is an organic silane material. The thickness range of the shell is 50nm to 500nm, and the surface active groups include any one or a combination of -NH2, -Cl, -SH, and vinyl. The thermal stability of the enhanced material is controlled by regulating the content of active groups such as amino groups and hydroxyl groups on the surface of the cooling agent material by a single or multiple silane ratio, thereby controlling the reaction activity of the cooling agent material. The problem of dehumidification of the cooling agent in the solid propellant is solved. At the same time, by introducing a silane coating layer, the shear force stability and thermal stability of the cooling agent material are effectively improved, and its adaptability under high load and complex environment is enhanced, which is very promising for improving the mechanical properties of low combustion temperature solid propellants.
[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit it. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims
1. A surface-coated modified cooling agent, characterized in that: The cooling agent particles are coated with the organosilane material to form a core-shell structure, wherein the core is the cooling agent particles and the shell is the organosilane material; The thickness of the shell is in the range of 50nm to 500nm, and the surface active groups of the surface-coated modified cooling agent include one or more of -NH2, -Cl, -SH, and vinyl.
2. The surface-coated modified cooling agent according to claim 1, characterized in that: The cooling agent particles include one of dihydroxyglyoxime, ammonium sulfate and ammonium oxalate.
3. The surface-coated modified cooling agent according to claim 1, characterized in that: The organic silane material includes one or more of tetraethyl orthosilicate, octadecyltrimethylsilane, γ-aminopropyltrimethoxysilane, vinyltriethoxysilane, mercaptotriethoxysilane and γ-chloropropyltrimethoxysilane.
4. A method for preparing the surface-coated modified cooling agent according to any one of claims 1 to 3, characterized in that: The following steps are involved: Step 1: prepare a first solution and a second solution respectively; The preparation method of the first solution comprises dispersing cooling agent particles into an ethanol solution and adjusting the pH value to 8 to 9 to obtain a first solution; The preparation method of the second solution includes dispersing an organosilane material into an ethanol solution to obtain a second solution; Step 2: adding the second solution to the first solution and reacting under the first condition; Step three: After the reaction is completed under the first conditions, filter, wash, and dry to obtain a surface-coated modified cooling agent.
5. The method for preparing the surface-coated modified cooling agent according to claim 4, characterized in that: The cooling agent material includes one of dihydroxyglyoxime, ammonium sulfate and ammonium oxalate.
6. The method for preparing the surface-coated modified cooling agent according to claim 4, characterized in that: The mass concentration of the cooling agent material in the first solution is 0.1 g / mL to 2.0 g / mL.
7. The method for preparing the surface-coated modified cooling agent according to claim 4, characterized in that: The organic silane material includes one or more of tetraethyl orthosilicate, octadecyltrimethylsilane, γ-aminopropyltrimethoxysilane, vinyltriethoxysilane, mercaptotriethoxysilane and γ-chloropropyltrimethoxysilane.
8. The method for preparing the surface-coated modified cooling agent according to claim 4, characterized in that: The mass concentration of the organosilane material in the second solution is 0.005 mg / mL to 0.10 mg / mL.
9. The method for preparing the surface-coated modified cooling agent according to claim 4, characterized in that: The first condition is stirring at 30° C. to 50° C. for 1 h to 6 h.