A graphene-doped light-controlled solid propellant formulation and its preparation method

Abstract

This invention discloses a graphene-doped light-controlled solid propellant formulation and its preparation method, belonging to the field of aerospace propulsion technology. The propellant, with a base component of 100 parts by mass, includes graphene. The base component consists of: 45-50 parts ammonium perchlorate, 25-35 parts ammonium nitrate, 15-20 parts pentaaminotetrazole, 1-5 parts poly(azide glycidyl ether), and 1-3 parts phenolic resin; the amount of graphene added is 0.4-3.0 parts. The preparation method includes: drying the raw materials, ball milling and vibrating sieve, adding acetone and ultrasonically mixing, introducing graphene and continuing ultrasonication, adding a binder and stirring, directionally freezing the slurry and then freeze-drying to obtain a precursor with a three-dimensional porous structure, and pressing to obtain the propellant grain. This invention uses graphene instead of traditional nano-carbon powder as a light absorber, and combines this with a freeze-drying process to construct a three-dimensional porous thermally conductive network, significantly improving laser energy utilization efficiency and combustion response speed.

Description

Technical Field

[0001] This invention relates to the field of aerospace propulsion technology, and in particular to a graphene-doped light-controlled solid propellant formulation and its preparation method. Background Technology

[0002] Microsatellites and nanosatellites have become an important direction for the development of modern space technology due to their advantages such as low cost, rapid networking capability, and high flexibility. In the propulsion systems of microsatellites and nanosatellites, solid chemical propulsion technology has attracted much attention due to its high thrust density and simple structure. However, traditional solid propulsion systems often struggle to achieve controllable start-stop and real-time thrust adjustment, limiting their application in complex attitude adjustment and orbit control missions. Laser-controlled chemical propulsion technology, as an emerging propulsion solution, utilizes external laser beam energy to trigger and maintain combustion, enabling on-demand ignition, extinguishing, and thrust adjustment of solid propellants, providing a new option for the attitude and orbit control propulsion systems of microsatellites and nanosatellites. Currently, mainstream laser-controlled solid propellant formulations mostly use a composite oxidant system of ammonium perchlorate and ammonium nitrate, with nano-carbon powder or carbon black as light absorbers. However, limited by the physical properties of these traditional carbon materials, the photothermal conversion efficiency of the propellant is relatively limited, making it difficult to construct an efficient microscopic heat-conducting network in the matrix. This results in significant combustion response lag in existing propellants under laser irradiation, manifested as a long ignition delay time, low combustion rate, and low energy utilization. Furthermore, traditional light-controlled solid propellants often employ solvent mixing followed by compression molding. While the process is simple, it is prone to problems such as absorber agglomeration, uneven component distribution, and discontinuous microscopic thermally conductive networks, further limiting the improvement of laser energy utilization efficiency and combustion response speed. Graphene, as a two-dimensional material with extremely high thermal conductivity and specific surface area, can play a dual role in propellants as a thermal management medium and a combustion catalyst. It can not only construct an efficient thermally conductive network at the microscale to accelerate the deep transfer and utilization of laser energy, but also promote the thermal decomposition of components due to its abundant surface active sites. However, there is currently no documented technology on the application of graphene and its derivatives as absorbers in light-controlled solid propellants, combined with freeze-drying processes to construct three-dimensional porous structures to improve the accuracy of light-controlled response.

[0003] Therefore, developing a light-controlled solid propellant formulation and its preparation method with fast response speed, short ignition delay, and high combustion controllability has become an urgent technical problem to be solved in this field. Summary of the Invention

[0004] The purpose of this invention is to provide a graphene-doped light-controlled solid propellant formulation and its preparation method. The graphene-doped light-controlled solid propellant comprises: 100 parts by weight of a base component, with added graphene. The base component consists of the following components: 45 to 50 parts of ammonium perchlorate, 25 to 35 parts of ammonium nitrate, 15 to 20 parts of pentaaminotetrazole, 1 to 5 parts of polyazoyl glycidyl ether, and 1 to 3 parts of phenolic resin; the amount of graphene added is 0.4 to 3.0 parts.

[0005] Furthermore, based on 100 parts by mass of the basic component, 2 parts of graphene are added. The basic component consists of the following components: 46.18 parts of ammonium perchlorate, 30 parts of ammonium nitrate, 18.82 parts of pentaaminotetrazole, 3 parts of polyazolidone glycidyl ether, and 2 parts of phenolic resin.

[0006] Furthermore, the graphene is a single-layer graphene powder with a sheet diameter of 0.5 to 5 μm and a thickness of 0.8 to 1.2 nm.

[0007] Furthermore, the polyazoyl glycidyl ether and phenolic resin are in a mass ratio of 3:2.

[0008] Furthermore, the propellant is a cylindrical propellant grain with a diameter of 6 mm, a length of 10 mm, and a density of 1.4 to 1.6 g / cm³.

[0009] Furthermore, the method for preparing the propellant includes the following steps:

[0010] Step S100: Dry the raw materials in an oven at a temperature of 50°C to 60°C for 4 to 6 hours.

[0011] Step S200: The gas-generating agent and oxidant are ball-milled and sieved. The corresponding mass of oxidant and gas-generating agent are weighed according to the ratio, placed in a beaker and mixed. Acetone is added as a dispersion medium. The amount of acetone added is enough to completely submerge the solid material. The mouth of the beaker is sealed with plastic wrap. The sealed beaker is placed in a 35°C water bath and the mixture is sonicated for 30 minutes using an ultrasonic instrument. The gas-generating agent pentaminotetrazole is sieved using a sieve frame with a mesh size greater than 300 mesh. The oxidants ammonium perchlorate and ammonium nitrate are sieved using a sieve frame with a mesh size range of 150 to 170 mesh.

[0012] Step S300: Introduce graphene into the mixture obtained in step S200 and continue ultrasonic treatment for 30 minutes;

[0013] Step S400: After ultrasonication, add the binder polyazolidone glycidyl ether and phenolic resin in sequence, transfer the beaker to a magnetic stirrer, and stir continuously at 20 rpm for 2 hours.

[0014] Step S500: Pour the stirred slurry into a mold and place it in a low temperature environment of -50°C to -20°C for directional freezing. After the slurry is completely solidified, transfer it to a freeze dryer and freeze dry it for 24 to 48 hours under a vacuum of less than 10 Pa. After removing the solvent, a propellant precursor with a three-dimensional porous structure is obtained.

[0015] Step S600: Remove the freeze-dried precursor from the mold and shape it into the required size by slight pressing;

[0016] In step S700, the shaped propellant grain is pressed using a hydraulic press at a pressure of 40 MPa to 60 MPa and a holding time of 30 to 50 seconds to obtain the final propellant grain.

[0017] Furthermore, in step S700, the pressing pressure is 50 MPa and the holding time is 40 seconds.

[0018] Furthermore, in step S500, the freeze-drying time is 36 hours.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] (1) This invention uses graphene instead of traditional nano-carbon powder as a light absorber, significantly improving the photothermal conversion efficiency and combustion response speed of the propellant. Graphene has extremely high thermal conductivity and specific surface area, constructing an efficient heat-conducting network inside the propellant to accelerate the deep transfer and utilization of laser energy. Tests showed that, under the same formulation conditions, the ignition delay time of the propellant using graphene as a light absorber was shortened by more than 60% compared to the propellant using nano-carbon powder as a light absorber. Within a laser power density range of 0.58 W / mm² to 1.11 W / mm², the ignition delay time was 75 ms to 200 ms, the extinguishing delay time was 10 ms to 20 ms, and the burning rate was 0.78 mm·s. -1 Up to 1.11 mm·s -1 .

[0021] (2) This invention uses a freeze-drying process to construct a three-dimensional porous structure. By directional freezing, graphene forms a continuous thermally conductive network inside the propellant column, allowing laser energy to penetrate deep into the propellant column along the porous channels, effectively improving the utilization efficiency of laser energy. At the same time, the freeze-drying process avoids the problems of light absorber agglomeration and uneven component distribution in traditional pressing and molding processes, ensuring batch-to-batch consistency of propellant performance.

[0022] (3) This invention uses ammonium perchlorate and ammonium nitrate as dual oxidants and pentaaminotetrazole as a gas-generating agent. By complementing the decomposition characteristics of the two oxidants, the precise control of the propellant combustion rate is achieved. Ammonium perchlorate provides rapid decomposition and excellent combustion performance, while ammonium nitrate regulates the combustion rate, making it easier for the propellant to achieve non-self-sustaining combustion, thereby improving the light control accuracy and combustion stability.

[0023] (4) The formulation of this invention has an absorption rate of 90% to 95% in the 982nm band, exhibiting excellent laser absorption performance, which can effectively utilize laser energy and improve energy utilization efficiency. The propellant is a cylindrical propellant grain with a diameter of 6mm, a length of 10mm, and a density of 1.4g / cm³ to 1.6g / cm³. It can be successfully ignited and optically controlled within a laser power range of 16.4W to 38.6W, meeting the requirements of micro-nano satellite attitude and orbit control propulsion systems for different thrust conditions.

[0024] The present invention will now be further described with reference to the accompanying drawings. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the production process of the propellant of the present invention. Detailed Implementation

[0026] A graphene-doped light-controlled solid propellant, comprising 100 parts by weight of a base component, with graphene added. The base component consists of the following components: 45 to 50 parts of ammonium perchlorate, 25 to 35 parts of ammonium nitrate, 15 to 20 parts of pentaaminotetrazole, 1 to 5 parts of polyazoyl glycidyl ether, and 1 to 3 parts of phenolic resin; the amount of graphene added is 0.4 to 3.0 parts.

[0027] Ammonium perchlorate, as the primary oxidizer, decomposes rapidly at high temperatures, releasing a large amount of oxygen and providing sufficient oxidizing components for the combustion reaction, thus giving the propellant excellent combustion performance and high thrust density. Ammonium nitrate, as a secondary oxidizer, has a higher decomposition temperature and slower combustion rate. It can adjust the combustion rate based on the rapid decomposition of ammonium perchlorate, making it easier for the propellant to achieve non-self-sustaining combustion, thereby improving combustion controllability and light control precision. Pentaaminotetrazole, as a gas-generating agent, has a high nitrogen content and produces a large amount of gaseous products after combustion, improving the propellant's combustion and propulsion performance. Poly(azide glycidyl ether), as an energetic binder, not only acts as a binder for the components in the formulation, giving the propellant grain good mechanical properties and overload resistance, but also participates in the exothermic reaction during combustion, increasing the propellant's energy density. Phenolic resin, as an auxiliary binder, can further improve the molding strength and structural stability of the propellant grain.

[0028] The graphene used is a single-layer graphene powder with a sheet diameter of 0.5 to 5 μm and a thickness of 0.8 to 1.2 nm. As a light absorber, graphene possesses extremely high thermal conductivity and specific surface area, enabling it to function as both a thermal management medium and a combustion catalyst in propellants. Graphene constructs a highly efficient thermally conductive network at the microscale, accelerating the deep transfer and utilization of laser energy, significantly improving laser energy utilization efficiency and combustion response speed. Simultaneously, graphene exhibits catalytic activity towards ammonium perchlorate, reducing the reaction activation energy and shortening the ignition delay time.

[0029] The optimal ratio of the basic components is: 46.18 parts ammonium perchlorate, 30 parts ammonium nitrate, 18.82 parts pentaaminotetrazole, 3 parts poly(azide glycidyl ether), and 2 parts phenolic resin; the optimal amount of graphene added is 2 parts. Tests showed that with this ratio, the propellant had an absorption rate of 90% to 95% in the 982nm wavelength band, an ignition delay time of 75ms to 200ms, a extinguishing delay time of 10ms to 20ms, and a burning rate of 0.78 mm·s. -1 Up to 1.11 mm·s -1 .

[0030] Reference Figure 1 , Figure 1 This is a schematic diagram of the production process of the graphene-doped light-controlled solid propellant of the present invention. The preparation method of this propellant includes the following steps:

[0031] Step S100: Dry the raw materials in an oven at a temperature of 50°C to 60°C for 4 to 6 hours.

[0032] Step S200 involves ball milling and vibrating sieve treatment of the gas-generating agent and oxidant. The gas-generating agent, pentaaminotetrazole, is sieved using a sieve frame with an aperture larger than 300 mesh; the oxidants, ammonium perchlorate and ammonium nitrate, are sieved using a sieve frame with an aperture range of 150 to 170 mesh. Weigh the corresponding masses of oxidant and gas-generating agent according to the formula, place them in a beaker, mix them, and add an appropriate amount of acetone as a dispersion medium. The amount of acetone added should be enough to completely submerge the solid material. Seal the beaker with plastic wrap. Place the sealed beaker in a 35°C water bath and sonicate the mixture for 30 minutes using an ultrasonic cleaner.

[0033] Step S300: Introduce graphene into the mixture obtained in step S200 and continue ultrasonic treatment for 30 minutes.

[0034] In step S400, after the ultrasound is completed, add the binder polyazoyl glycidyl ether and phenolic resin in sequence, transfer the beaker to a magnetic stirrer, and stir continuously at 20 rpm for 2 hours.

[0035] In step S500, the stirred slurry is poured into a mold and placed in a low-temperature environment of -50°C to -20°C for directional freezing. After the slurry has completely solidified, it is transferred to a freeze dryer and freeze-dried for 24 to 48 hours under a vacuum of less than 10 Pa. After removing the solvent, a propellant precursor with a three-dimensional porous structure is obtained. During the directional freezing process, the solvent grows into ice crystals in a specific direction in the mold. After freeze-drying, the ice crystals sublimate, forming directional porous channels in situ. These porous channels provide a continuously distributed spatial carrier for graphene, enabling graphene to form a continuous thermally conductive network inside the propellant grain. Laser energy can penetrate deep into the propellant grain along the porous channels, effectively improving the utilization efficiency of laser energy.

[0036] In step S600, the freeze-dried precursor is removed from the mold and slightly pressed and shaped to the required size.

[0037] In step S700, the shaped propellant grains are pressed using a hydraulic press at a pressure of 40 MPa to 60 MPa for a holding time of 30 to 50 seconds, yielding the final propellant grains. This step, performed at relatively low pressure, preserves the porous thermally conductive network formed by freeze-drying while ensuring the mechanical strength and dimensional accuracy of the propellant grains, enabling them to meet the overload resistance requirements during loading and use.

[0038] The technical effects of the present invention will be further explained below with reference to specific embodiments and comparative examples.

[0039] Example 1: Based on 100 parts by mass of the basic components, the following components were weighed: ammonium perchlorate 46.18 parts, ammonium nitrate 30 parts, pentaaminotetrazole 18.82 parts, polyazolidone glycidyl ether 3 parts, phenolic resin 2 parts, and graphene 2 parts. Propellant grains were prepared according to steps S100 to S700 described above. The propellant grains had a diameter of 6 mm and a length of 10 mm. Testing was conducted under conditions of 16.4 W laser power and a spot diameter of 6 mm, corresponding to a laser power density of 0.58 W / mm². The propellant successfully ignited and achieved optical control, with an ignition delay time of 200 ms, a quenching delay time of 9 ms, and a burning rate of 0.81 mm / s.

[0040] Example 2 is the same as Example 1, except that the laser power density is changed to 0.72 W / mm². The propellant can be successfully ignited and optically controlled, with an ignition delay time of 157 ms, a quenching delay time of 11 ms, and a burning rate of 0.88 mm / s.

[0041] Example 3 is the same as Example 1, except that the laser power density is changed to 0.85 W / mm². The propellant can be successfully ignited and optically controlled, with an ignition delay time of 119.3 ms, a quenching delay time of 13.3 ms, and a burning rate of 0.96 mm / s.

[0042] Example 4 is the same as Example 1, except that the laser power density is changed to 0.98 W / mm². The propellant can be successfully ignited and optically controlled, with an ignition delay time of 92 ms, a quenching delay time of 17 ms, and a burning rate of 1.04 mm / s.

[0043] Example 5 is the same as Example 1, except that the laser power density is changed to 1.11 W / mm². The propellant can be successfully ignited and optically controlled, with an ignition delay time of 74 ms, a quenching delay time of 19 ms, and a burning rate of 1.11 mm / s.

[0044] Comparative Example 1, based on 100 parts by weight of the basic components, replaced 46.18 parts of ammonium perchlorate and 30 parts of ammonium nitrate in the basic components with 80 parts of nitroguanidine as the oxidant, and replaced 3 parts of poly(azide glycidyl ether) and 2 parts of phenolic resin as the binder with 2 parts of a mixture of HTPB and PF. The remaining components were the same as in Example 1. Tests were conducted under conditions of a laser power density of 0.35 W / mm² and a spot diameter of 6 mm. This comparative example successfully ignited and achieved photocontrol, with an ignition delay time of 110 ms.

[0045] Comparative Example 2, based on 100 parts by mass of the base component, replaced 46.18 parts of ammonium perchlorate and 30 parts of ammonium nitrate in the base component with 72.3 parts of ADN as the oxidant, and used 2 parts of a mixture of GAP and NC as the binder. The remaining components were the same as in Example 1. Tests were conducted under conditions of a laser power density of 0.90 W / mm² and a spot diameter of 6 mm. This comparative example successfully ignited and achieved optical control, with an ignition delay time of 100 ms.

[0046] Comparative Example 3, based on 100 parts by mass of the basic components, used 46.18 parts of ammonium perchlorate and 30 parts of ammonium nitrate, the same as in Example 1, as the oxidant, and 2 parts of nano-carbon powder instead of graphene as the light absorber. The remaining components were the same as in Example 1. Tests were conducted under conditions of a laser power density of 1.059 W / mm² and a spot diameter of 6 mm. This comparative example successfully ignited and achieved light control, with an ignition delay time of 234 ms. Comparative Example 3 differs from Example 1 only in the type of light absorber. Under the same laser power density conditions, the ignition delay time of Example 1 was shortened by more than 60% compared to Comparative Example 3, indicating that replacing nano-carbon powder with graphene as the light absorber significantly improved the photothermal conversion efficiency and combustion response speed of the propellant.

[0047] As can be seen from the above embodiments and comparative examples, this invention uses ammonium perchlorate and ammonium nitrate as oxidizing agents, pentaaminotetrazole as a gas-generating agent, and graphene instead of traditional nano-carbon powder as a light absorber. Combined with a freeze-drying process to construct a three-dimensional porous structure, a continuous heat-conducting network is formed inside the propellant column, significantly improving laser energy utilization efficiency and combustion response speed. The catalytic activity of graphene on ammonium perchlorate can reduce the reaction activation energy, further shortening the ignition delay time. The propellant has an absorption rate of 90% to 95% in the 982nm band, an ignition delay time of 75ms to 200ms, a quenching delay time of 10ms to 20ms, and a burning rate of 0.78mm·s. -1 Up to 1.11 mm·s -1 It has good light control response characteristics and promising prospects for engineering applications.

Claims

1. A graphene-doped light-controlled solid propellant, characterized in that, Based on 100 parts by mass of the base component, with the addition of graphene, The basic components consist of the following: 45 to 50 parts of ammonium perchlorate, 25 to 35 parts of ammonium nitrate, 15 to 20 parts of pentaaminotetrazole, 1 to 5 parts of polyazoyl glycidyl ether, and 1 to 3 parts of phenolic resin; the amount of graphene added is 0.4 to 3.0 parts.

2. The graphene-doped light-controlled solid propellant according to claim 1, characterized in that, Based on 100 parts by mass of the basic component, 2 parts of graphene are added. The basic components consist of the following: 46.18 parts ammonium perchlorate, 30 parts ammonium nitrate, 18.82 parts pentaaminotetrazole, 3 parts polyazoyl glycidyl ether, and 2 parts phenolic resin.

3. The graphene-doped light-controlled solid propellant according to claim 1, characterized in that, Graphene is a single-layer graphene powder with a sheet diameter of 0.5 to 5 μm and a thickness of 0.8 to 1.2 nm.

4. The graphene-doped light-controlled solid propellant according to claim 1, characterized in that, The mass ratio of polyazidoglycidyl ether to phenolic resin is 3:

2.

5. The graphene-doped light-controlled solid propellant according to claim 1, characterized in that, The propellant is a cylindrical propellant grain with a diameter of 6 mm, a length of 10 mm, and a density of 1.4 to 1.6 g / cm³.

6. The method for preparing the light-controlled solid propellant doped with graphene according to any one of claims 1 to 5, characterized in that, Includes the following steps: Step S100: Dry the raw materials in an oven at a temperature of 50°C to 60°C for 4 to 6 hours. Step S200: The gas-generating agent and oxidant are ball-milled and sieved. The corresponding mass of oxidant and gas-generating agent are weighed according to the ratio, placed in a beaker and mixed. Acetone is added as a dispersion medium. The amount of acetone added is enough to completely submerge the solid material. The mouth of the beaker is sealed with plastic wrap. The sealed beaker is placed in a 35°C water bath and the mixture is sonicated for 30 minutes using an ultrasonic instrument. The gas-generating agent pentaminotetrazole is sieved using a sieve frame with a mesh size greater than 300 mesh. The oxidants ammonium perchlorate and ammonium nitrate are sieved using a sieve frame with a mesh size range of 150 to 170 mesh. Step S300: Introduce graphene into the mixture obtained in step S200 and continue ultrasonic treatment for 30 minutes; Step S400: After ultrasonication, add the binder polyazolidone glycidyl ether and phenolic resin in sequence, transfer the beaker to a magnetic stirrer, and stir continuously at 20 rpm for 2 hours. Step S500: Pour the stirred slurry into a mold and place it in a low temperature environment of -50°C to -20°C for directional freezing. After the slurry is completely solidified, transfer it to a freeze dryer and freeze dry it for 24 to 48 hours under a vacuum of less than 10 Pa. After removing the solvent, a propellant precursor with a three-dimensional porous structure is obtained. Step S600: Remove the freeze-dried precursor from the mold and shape it into the required size by slight pressing; In step S700, the shaped propellant grain is pressed using a hydraulic press at a pressure of 40 MPa to 60 MPa and a holding time of 30 to 50 seconds to obtain the final propellant grain.

7. The method for preparing the graphene-doped light-controlled solid propellant according to claim 6, characterized in that, In step S700, the pressing pressure is 50 MPa and the holding time is 40 seconds.

8. The method for preparing the graphene-doped light-controlled solid propellant according to claim 6, characterized in that, In step S500, the freeze-drying time is 36 hours.

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