Chopped carbon fiber burning rate catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of solid propellants and particularly discloses a chopped carbon fiber burning rate catalyst as well as a preparation method and application thereof. The invention relates to a preparation method of a short carbon fiber burning rate catalyst, which comprises the following steps: 1, soaking short carbon fibers in an organic solvent to form a suspension, and carrying out ultrasonic stirring; the ratio of the short carbon fiber to the organic solvent is 1 g: 10 ml-100 ml; 2, separating the short carbon fibers in the suspension after ultrasonic stirring, dispersing the separated short carbon fibers in deionized water, adjusting the pH value, and removing the deionized water; and 3, washing with an organic solvent, filtering, and drying to obtain the chopped carbon fiber burning rate catalyst. The development requirements of high-performance propellants can be met, the burning rate and the pressure index of the propellants can be remarkably improved under the condition of low addition amount (such as five thousandths of dosage), and meanwhile, the modulus is greatly improved. The production cost is effectively reduced, and the overall efficiency of the propulsion system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of solid propellants, and particularly to a chopped carbon fiber burning rate catalyst, a preparation method thereof, and an application thereof. Background Art

[0002] In today's propellant technology field, especially in the research and development and application of solid rocket propellants, solid fuel propellants, and various high-performance propellants, increasing the burning rate and pressure exponent is the key to improving the performance of the propulsion system and achieving more efficient energy conversion and utilization. In the prior art, various means such as adding high-energy additives, optimizing the formulation composition, and improving the manufacturing process are usually adopted. However, these methods are often accompanied by increased costs, increased process complexity, and possible environmental and safety risks.

[0003] Carbon fiber is a fibrous material with a carbon content of more than 90%, and has characteristics such as heat resistance, chemical stability, electrothermal conductivity, low thermal expansion, and good mechanical properties. It has been widely used in fields such as composite materials, structural reinforcement, and conductive materials. As a burning rate catalyst, carbon fiber can reduce the peak temperature of thermal decomposition of propellant components and increase the initial heat release of the propellant, thereby resulting in an increase in the burning rate of the propellant. In recent years, the research on introducing carbon fiber into the propellant as a performance enhancer has gradually emerged, but most of them focus on the form of long fibers or continuous fibers, and there are certain limitations in the dispersibility, processability, and ultimately the improvement effect on the burning rate and pressure exponent in the propellant. It has been found during use that longer carbon fibers are more likely to form a heat conduction network in the propellant, and the burning rate catalytic effect is better. However, the mixing uniformity of longer carbon fibers in the propellant slurry is poor, seriously affecting the compactness of the propellant.

[0004] In particular, while pursuing higher performance, how to effectively control the dosage of additives to reduce the negative impact on the overall composition and cost of the propellant has become an urgent problem to be solved. Summary of the Invention

[0005] In view of the above problems, the first object of the present invention is to provide a preparation method of a chopped carbon fiber burning rate catalyst.

[0006] The second object of the present invention is to provide a chopped carbon fiber burning rate catalyst.

[0007] The third object of the present invention is to provide an application of a chopped carbon fiber burning rate catalyst.

[0008] It can meet the development requirements of high-performance propellants, significantly increase the burning rate and pressure exponent of propellants at a low addition amount (such as 0.5‰ dosage), and at the same time greatly improve the modulus. It effectively reduces the production cost and improves the overall efficiency of the propulsion system, which is of great significance for promoting technological progress in the fields of aerospace, aviation, military and other related fields.

[0009] To achieve the first object, the first technical solution of the present invention is: a preparation method of a chopped carbon fiber burning rate catalyst, comprising the following steps:

[0010] Step 1: Immerse the chopped carbon fiber in an organic solvent to form a suspension, and perform ultrasonic stirring; the ratio of the chopped carbon fiber to the organic solvent is 1 g: 10 ml to 100 ml;

[0011] Step 2: Separate the chopped carbon fiber in the suspension after ultrasonic stirring, then disperse the separated chopped carbon fiber in deionized water and adjust the pH value, and remove the deionized water;

[0012] Step 3: Wash with an organic solvent, filter, and dry to obtain a chopped carbon fiber burning rate catalyst.

[0013] Preferably, the length of the chopped carbon fiber is 3 mm to 12 mm.

[0014] Preferably, the organic solvent includes one or more of methanol, toluene, acetonitrile, ethanol, ether, ethyl acetate, dichloromethane, dimethyl sulfoxide, acetone, isopropanol, tetrahydrofuran, cyclohexane, petroleum ether, N,N-dimethylformamide.

[0015] Preferably, the method for adjusting the pH value includes: using sodium bicarbonate or dilute hydrochloric acid to adjust the pH value = 7.

[0016] Preferably, the conditions for ultrasonic stirring are: ultrasonic stirring at room temperature ≥ 10 hours.

[0017] Preferably, the drying conditions are: 50 °C to 70 °C, vacuum drying, and the drying duration ≥ 12 hours.

[0018] To achieve the second object, the second technical solution of the present invention is: a chopped carbon fiber burning rate catalyst prepared by using the preparation method of a chopped carbon fiber burning rate catalyst.

[0019] To achieve the third object, the third technical solution of the present invention is: an application of a chopped carbon fiber burning rate catalyst, and the application of the chopped carbon fiber burning rate catalyst in a solid propellant.

[0020] Preferably, the dosage of the chopped carbon fiber burning rate catalyst in the solid propellant is 0.50% to 4.00%.

[0021] Preferably, the amount of the chopped carbon fiber burning rate catalyst in the solid propellant is 0.50% - 2.00%.

[0022] Advantages of the above technical solution:

[0023] Compared with the burning rate catalysts in the prior art, the chopped carbon fiber burning rate catalyst provided by the present invention has greatly improved dispersibility and mixing uniformity in the propellant, and its performance is further improved when applied in the solid propellant.

[0024] The chopped carbon fiber burning rate catalyst prepared by the preparation method of the chopped carbon fiber burning rate catalyst provided by the present invention can improve the catalytic effect of the chopped carbon fiber. The amount of the burning rate catalyst used is less, which helps to reduce the energy loss of the propellant and simultaneously improve the burning rate and pressure index of the propellant.

[0025] The chopped carbon fiber burning rate catalyst provided by the present invention can greatly increase the modulus of the propellant while increasing the burning rate, and has a wide application prospect in solid propellants. Specific embodiments

[0026] The following further describes in detail the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than an exhaustive list of all embodiments. It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments can be combined with each other.

[0027] The terms "first", "second", etc. (if any) in the specification and claims are used to distinguish similar objects, and do not necessarily have to be used to describe a specific order or sequence. It should be understood that such used data can be interchanged under appropriate circumstances so that the embodiments described herein can be implemented in an order different from that described herein. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products or devices.

[0028] It should be understood that the term " / and" used herein is only a description of the association relationship of associated objects, indicating that three relationships may exist. For example, A / and B may represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " herein generally represents an "or" relationship between the associated objects before and after.

[0029] (1) Preparation method of the chopped carbon fiber burning rate catalyst provided by the present invention

[0030] It includes the following steps:

[0031] Soak the short carbon fiber (with a length of 3 mm to 12 mm) in an organic solvent, and the ratio of the short carbon fiber to the organic solvent is 1 g: 10 ml to 100 ml. Place the container containing the soaked short carbon fiber in an ultrasonic stirring device and stir ultrasonically at room temperature for ≥ 10 h. Filter to remove the organic solvent, separate the short carbon fiber and disperse it in deionized water, and adjust the pH value to 7 using sodium bicarbonate or dilute hydrochloric acid. Filter to remove the deionized water, wash it several times with an organic solvent, filter, and vacuum dry at 50 °C to 70 °C for ≥ 12 h to obtain the short carbon fiber burning rate catalyst.

[0032] The organic solvent includes one or more of methanol, toluene, acetonitrile, ethanol, ether, ethyl acetate, dichloromethane, dimethyl sulfoxide, acetone, isopropanol, tetrahydrofuran, cyclohexane, petroleum ether, and N, N-dimethylformamide.

[0033] (2) Application of the short carbon fiber burning rate catalyst provided by the present invention

[0034] The percentage of the short carbon fiber burning rate catalyst in the total mass of the solid propellant is 0.50% to 4.00%, preferably 0.50% to 2.00%.

[0035] The specific composition of the solid propellant includes: 5 - 15 parts of polyurethane binder, 2 - 40 parts of plasticizer, 0 - 60 parts of ammonium perchlorate AP, 0 - 60 parts of cyclotrimethylenetrinitramine RDX or cyclotetramethylene tetranitramine HMX or hexanitrohexaazaisowurtzitane, 0 - 20 parts of aluminum powder Al, 0.3 - 2.0 parts of curing agent, and 1 - 5 parts of functional additive.

[0036] The polyurethane binder includes one or a combination of hydroxyl-terminated polybutadiene HTPB, glycidyl azide polymer GAP, ethylene oxide-tetrahydrofuran copolymer ether PET, or polyethylene glycol PEG.

[0037] The plasticizer includes one or a combination of dioctyl sebacate DOS, nitroglycerin (NG), butanetriol trinitrate (BTTN), diethylene glycol dinitrate (TEGDN), and diethylene glycol dinitrate (DEGDN).

[0038] The curing agent is one or a combination of isophorone diisocyanate IPDI, toluene diisocyanate TDI, 1,6-hexamethylene diisocyanate HDI, or polyfunctional isocyanate N-100.

[0039] The functional additive includes a curing catalyst, an antioxidant, and a burning rate catalyst; the curing catalyst is triphenylbismuth TPB, the antioxidant is N-methyl-p-nitroaniline MNA and 2-nitrodiphenylamine 2-NDPA; the burning rate catalyst is the short carbon fiber burning rate catalyst provided by the present invention.

[0040] Example 1

[0041] This example provides a chopped carbon fiber burning rate catalyst, denoted as BRC-1, and the preparation method is as follows:

[0042] Soak 10 g of chopped carbon fibers with a length of 3 mm in 100 mL of organic solvent. Preferred organic solvents are ethanol, ethyl acetate, isopropanol, and tetrahydrofuran. Stir ultrasonically at room temperature for 10 h; filter to remove the solvent, disperse the chopped carbon fibers in deionized water, and adjust the pH = 7; filter to remove deionized water, wash several times with organic solvent, filter, and dry in vacuum at 50 °C to 70 °C for 12 h to obtain the treated chopped carbon fibers, thus obtaining BRC-1.

[0043] Example 2

[0044] This example provides a chopped carbon fiber burning rate catalyst, denoted as BRC-2. The difference in the preparation method from Example 1 is that the length of the chopped carbon fibers is 6 mm, and the preferred organic solvents are methanol, toluene, ether, dichloromethane, and acetone.

[0045] Example 3

[0046] This example provides a chopped carbon fiber burning rate catalyst, denoted as BRC-3. The difference in the preparation method from Example 1 is that the length of the chopped carbon fibers is 12 mm, and the preferred organic solvents are acetonitrile, dimethyl sulfoxide, cyclohexane, and N,N-dimethylformamide.

[0047] Comparative Example 1

[0048] This comparative example provides a chopped carbon fiber burning rate catalyst with a length of 3 mm that has not been treated by the method provided in the present invention, that is, the raw material chopped carbon fiber burning rate catalyst, denoted as BRC-4.

[0049] Comparative Example 2

[0050] This comparative example provides an untreated chopped carbon fiber burning rate catalyst BRC-5 with a length of 6 mm. Application and performance of chopped carbon fiber burning rate catalyst in GAP propellant

[0051] The short-cut carbon fiber burning rate catalyst provided by the present invention is applied to a solid propellant. The specific composition of the solid propellant includes: 5-15 parts of polyurethane binder, 2-40 parts of plasticizer, 0-60 parts of ammonium perchlorate (AP), 0-60 parts of cyclotrimethylenetrinitramine (RDX) or cyclotetramethylenetetranitramine (HMX) or hexanitrohexaazaisowurtzitane, 0-20 parts of aluminum powder (Al), 0.3-2.0 parts of curing agent, and 1-5 parts of functional additives. The polyurethane binder includes one or a combination of hydroxyl-terminated polybutadiene (HTPB), glycidyl azide polymer (GAP), ethylene oxide-tetrahydrofuran copolymer ether (PET), or polyethylene glycol (PEG). The plasticizer includes one or a combination of dioctyl sebacate (DOS), nitroglycerin (NG), butanetriol trinitrate (BTTN), diethylene glycol dinitrate (TEGDN), or diethylene glycol dinitrate (DEGDN). The curing agent is one or a combination of isophorone diisocyanate (IPDI), toluene diisocyanate (TDI), 1,6-hexamethylene diisocyanate (HDI), or polyfunctional isocyanate N-100. The functional additives include a curing catalyst, an antioxidant, and a burning rate catalyst; the curing catalyst is triphenyl bismuth (TPB), the antioxidant is N-methyl-p-nitroaniline (MNA) and 2-nitrodiphenylamine (2-NDPA); the burning rate catalyst is the short-cut carbon fiber burning rate catalyst provided by the present invention.

[0052] The specific components of the GAP propellant are shown in Table 1 below, and the burning rate catalysts used are those provided in Examples 1-3 and Comparative Examples 1-2.

[0053] Table 1 GAP propellant formulation

[0054]

[0055] The test results of the burning rate and pressure exponent of the solid propellant grain are shown in Table 2, where the blank group is the GAP propellant formulation shown in Table 1 without adding a burning rate catalyst.

[0056] Table 2 Burning rate and pressure exponent of solid propellants with different burning rate catalysts

[0057]

[0058]

[0059] The maximum tensile strength σ m 、maximum elongation ε m and initial modulus E 0 of the solid propellant grain at 20 °C and a pulling speed of 100 mm / min are shown in Table 3, where the blank group did not add a burning rate catalyst.

[0060] Table 3 Room temperature mechanical properties of solid propellants with different burning rate catalysts at different aging times

[0061]

[0062] As can be seen from the above embodiments, in the GAP propellant formulation, the use effect of the treated chopped carbon fiber burning rate catalyst is better than that of the untreated carbon fiber, the burning rate and pressure exponent of the propellant both increase, and at the same time, the room temperature modulus of the propellant is greatly improved.

[0063] The specific components of the HTPB propellant are shown in Table 4 below, and the burning rate catalysts used are those provided in Examples 1 to 3 and Comparative Examples 1 to 2.

[0064] Table 4 HTPB Propellant Formulation

[0065]

[0066]

[0067] The test results of the burning rate and pressure exponent of the solid propellant grain are shown in Table 5, where the blank group is the propellant formulation shown in Table 4 without adding a burning rate catalyst.

[0068] Table 5 Burning Rate and Pressure Exponent of Solid Propellants with Different Burning Rate Catalysts

[0069]

[0070] The maximum tensile strength σ m , maximum elongation ε m and initial modulus E 0 of the solid propellant grain at 20 °C and a pulling speed of 100 mm / min are shown in Table 6, where the blank is the HTPB propellant formulation shown in Table 4 without adding a burning rate catalyst.

[0071] Table 6 Room Temperature Mechanical Properties of Solid Propellants with Different Burning Rate Catalysts at Different Aging Times

[0072]

[0073] As can be seen from the above embodiments, in the HTPB propellant formulation, the use effect of the treated chopped carbon fiber burning rate catalyst is better than that of the untreated carbon fiber, which can increase both the burning rate and pressure exponent of the propellant, and at the same time, greatly improve the room temperature modulus of the propellant.

[0074] As can be seen from the above embodiments, in the propellant formulation, the use effect of the treated chopped carbon fiber burning rate catalyst is better than that of the untreated carbon fiber. Among them, BRC-3 has the best use effect. A dosage of 0.5% can increase both the burning rate and pressure exponent of the propellant, and at the same time, greatly improve the room temperature modulus of the propellant, and can be promoted as a solid propellant burning rate catalyst.

[0075] Obviously, the above-mentioned embodiments of the present invention are merely examples for clearly illustrating the present invention, rather than limitations on the implementation manners of the present invention. For those of ordinary skill in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation manners here. Any obvious changes or modifications derived from the technical solutions of the present invention still fall within the protection scope of the present invention.

Claims

1. A method for preparing a chopped carbon fiber combustion rate catalyst, characterized in that: The steps include: Step 1: Soaking the chopped carbon fiber in an organic solvent to form a suspension, and performing ultrasonic stirring; the ratio of the chopped carbon fiber to the organic solvent is 1g:10ml-100ml; Step 2: separating the chopped carbon fibers in the suspension after ultrasonic stirring, dispersing the separated chopped carbon fibers in deionized water, adjusting the pH value, and removing the deionized water; Step three: washing with an organic solvent, filtering, and drying to obtain a chopped carbon fiber combustion rate catalyst.

2. The method for preparing the chopped carbon fiber combustion rate catalyst according to claim 1, characterized in that: The length of the chopped carbon fiber is 3 mm to 12 mm.

3. The method for preparing the chopped carbon fiber combustion rate catalyst according to claim 1, characterized in that: The organic solvent includes one or more of methanol, toluene, acetonitrile, ethanol, ether, ethyl acetate, dichloromethane, dimethyl sulfoxide, acetone, isopropanol, tetrahydrofuran, cyclohexane, petroleum ether, and N,N-dimethylformamide.

4. The method for preparing the chopped carbon fiber combustion rate catalyst according to claim 1, characterized in that: The method for adjusting the pH value includes: using sodium bicarbonate or dilute hydrochloric acid to adjust the pH value to 7.

5. The method for preparing the chopped carbon fiber combustion rate catalyst according to claim 1, characterized in that: The ultrasonic stirring condition is: ultrasonic stirring at room temperature for ≥ 10 hours.

6. The method for preparing the chopped carbon fiber combustion rate catalyst according to claim 1, characterized in that: The drying conditions are: 50° C. to 70° C., vacuum drying, and drying time ≥ 12 hours.

7. A chopped carbon fiber combustion rate catalyst prepared by the method for preparing a chopped carbon fiber combustion rate catalyst according to any one of claims 1 to 6.

8. An application of the chopped carbon fiber combustion rate catalyst as claimed in claim 7, characterized in that: Application of the chopped carbon fiber burning rate catalyst in solid propellant.

9. The use of the chopped carbon fiber combustion rate catalyst according to claim 8, characterized in that: The usage of the chopped carbon fiber burning rate catalyst in the solid propellant is 0.50% to 4.00%.

10. The use of the chopped carbon fiber combustion rate catalyst according to claim 8, characterized in that: The usage of the chopped carbon fiber burning rate catalyst in the solid propellant is 0.50% to 2.00%.

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