Application of polymer reinforced fiber material as reinforcing material in propellant to improve mechanical properties
By adding polyvinyl alcohol (PVA) fibers to the propellant to form a mechanical skeleton, the problems of solid particle agglomeration and dehydration in the propellant are solved, improving the mechanical and combustion properties of the propellant while maintaining stable energy performance.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- NANJING UNIV OF SCI & TECH
- Filing Date
- 2026-02-05
- Publication Date
- 2026-05-29
AI Technical Summary
The use of high-energy-density compounds in existing propellants leads to solid particle agglomeration and dehydration, resulting in a decline in mechanical properties. Traditional methods, such as increasing the content of plasticizers and modifying with nitrocellulose, have limited effects.
Polyvinyl alcohol (PVA) fibers are added to the propellant as a reinforcing material to form a mechanical skeleton. By uniformly dispersing and adding them in batches before plasticization, a fiber network is constructed to prevent crack initiation and propagation.
It improves the impact resistance, compressive strength and combustion performance of the propellant, while maintaining stable energy performance and combustion performance, without changing the existing production process.
Smart Images
Figure CN122102809A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of propellant technology and relates to the application of a polymer-reinforced fiber material as a reinforcing material in propellants to improve mechanical properties. Background Technology
[0002] Propellants are used in various barrel-mounted weapon systems of the land, sea, and air forces. They are a crucial energy source for the destructive power of warheads in barrel-mounted weapons (guns and cannons). Therefore, good mechanical properties play a vital role in the regular release of propellant energy. As the energy of propellants increases, more high-energy-density compounds, such as the high-energy nitramine solid explosive RDX, need to be added, while the polymer binder content needs to be reduced. The continuous increase in solid content makes it difficult for solid particles to disperse, leading to agglomeration. Agglomerated solid particles are prone to "dehydration" under external forces. Solid particles fall from the binder matrix, creating cracks. When subjected to external forces, these cracks expand, easily leading to propellant breakage and a decrease in its mechanical properties.
[0003] Reinforcing materials are used to enhance the mechanical properties of other materials and are widely used in rubber, plastics, electronics, and construction. They mainly include carbon black, silica, fibers, fabrics, and steel wire. Among these, polyvinyl alcohol (PVA) fiber reinforcement is widely used in construction and other fields. In concrete modification, PVA fiber, as a new type of synthetic fiber, has high tensile strength, high elastic modulus, good hydrophilicity, and excellent adhesion to the cement matrix. Adding PVA fiber to concrete can effectively inhibit early cracking, reduce brittleness, enhance toughness, and improve impact resistance. In the construction field, the "reinforced concrete" structure effectively improves the strength of buildings. The reinforcing steel, as a skeleton, plays a crucial role in supporting the structural strength, and constructing a mechanical framework can effectively improve various mechanical properties of the material. Traditional methods for improving the mechanical properties of propellants mainly include increasing the plasticizer content, increasing the types of plasticizers, and modifying nitrocellulose. Summary of the Invention
[0004] To achieve these objectives and other advantages of the present invention, a method for using polymer-reinforced fiber materials as reinforcing materials in propellants to improve mechanical properties is proposed.
[0005] The implementation process of this invention is as follows:
[0006] Before plasticization, PVA is uniformly dispersed in the propellant tablet, and then plasticized to obtain the propellant sample.
[0007] This invention proposes to liken reinforcing PVA fibers to "steel bars" and the propellant matrix to "concrete," using the reinforcing fibers to construct a mechanical framework and improve the mechanical properties of the propellant. Currently, there are no applications of using reinforcing fibers as a strengthening material to enhance the mechanical properties of propellants, thus utilizing the principle of enhancing the strength of concrete to improve the mechanical properties of propellants.
[0008] Preferably, the polyvinyl alcohol (PVA) monofilament fiber has a length of 3 mm, a diameter of 15 micrometers, and the average molecular weight of the raw material polyvinyl alcohol is 60,000 to 150,000.
[0009] Preferably, PVA is used as an additive material, and the mass ratio of PVA to the propellant absorber tablet is 0.005:1, 0.010:1, and 0.015:1.
[0010] Preferably, in order to ensure that the fiber is evenly dispersed in the propellant, the amount of fiber added in each batch shall not exceed 0.05% of the amount of absorbent tablet, and the fiber shall be added in at least two batches, with the stirring and dispersion time after each batch of fiber is added not less than 10 minutes.
[0011] Preferably, in order to ensure that the fiber is evenly dispersed in the propellant, PVA is added to the tablet in batches before plasticizing and the mixture is stirred and dispersed evenly before plasticizing.
[0012] Preferably, the propellant is NC-NG-RDX nitrate propellant.
[0013] This invention innovatively uses reinforcing fibers in propellants, thereby improving the mechanical properties of the propellants.
[0014] This invention utilizes polyvinyl alcohol (PVA), which has excellent dispersibility. When distributed in the propellant, the fibers form a dense and robust mechanical skeleton, improving the propellant's load-bearing capacity under external forces. Simultaneously, the fibers are in close contact with the propellant matrix, and through the tensile action of the fibers, the generation and propagation of internal cracks in the propellant can be effectively prevented. After adding PVA, the mechanical properties of the propellant are improved.
[0015] Compared with the prior art, the present invention has the following characteristics:
[0016] (1) The present invention uses low-cost polyvinyl alcohol (PVA) fiber as a reinforcing material. Thanks to the good mechanical properties of PVA fiber and the skeleton network formed inside the propellant, it prevents the generation and expansion of cracks when the propellant is subjected to external impact, thus improving the mechanical properties of the propellant to a limited extent.
[0017] (2) This material can be added to the propellant formulation system as an external material, with little impact on the energy performance and combustion performance of the propellant; at the same time, PVA fiber has good compatibility with each component in the propellant and good storage safety.
[0018] (3) This material is easy to use. The finished material can be used directly without any processing. It can be added in batches before plasticization. No extra steps are required, and the original production process is not changed. The material does not contain energy, which can ensure that no additional risk factors are introduced during the production process. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of fiber distribution and reinforcement mechanism within the propellant.
[0020] Figure 2 The Pt curves are for GX, GX-1, GX-2, and GX-3.
[0021] Figure 3 The uP curves are for GX, GX-1, GX-2, and GX-3.
[0022] Figure 4 This is an image of the fracture point of the GX chip.
[0023] Figure 5 This is an image of the fracture site of the GX-1.
[0024] Figure 6 This is an image of the fracture site of the GX-2.
[0025] Figure 7 This is an image of the fracture site of the GX-3. Detailed Implementation
[0026] To better understand the technical content of this invention, specific embodiments are provided below in conjunction with the accompanying drawings:
[0027] This invention is illustrated by the following examples, but these examples are for illustrative purposes only and should not be construed as limiting the scope or application of the invention. Unless otherwise specified, all materials used in this invention are commercially available.
[0028] Example 1: Preparation of a comparative blank propellant
[0029] 1 kg of weighed propellant absorber tablets were added to a kneader for plasticization. After plasticization, a blank propellant sample was obtained by molding using a mold, denoted as GX.
[0030] Example 2: Preparation of a propellant with added 0.05% PVA
[0031] 1 kg of weighed propellant absorber tablets were added to a kneader, and 5.0 g of PVA fiber was added in two batches (0.025% of the mass of the absorber tablets per batch) for dispersion. After each batch of fiber was added, the mixture was stirred and dispersed for 10 minutes. Once the dispersion was uniform, plasticization began. After plasticization, the propellant sample was formed using a mold and designated as GX-1.
[0032] Example 3: Preparation of a propellant with added 0.10% PVA
[0033] 1 kg of weighed propellant absorber tablets were added to a kneader, and 10.0 g of PVA fiber was added in two batches (0.05% of the weight of the absorber tablets per batch) for dispersion. After each batch of fiber was added, the mixture was stirred and dispersed for 10 minutes. Once the dispersion was uniform, plasticization began. After plasticization, the propellant sample was formed using a mold and designated as GX-2.
[0034] Example 4: Preparation of a propellant with added 0.15% PVA
[0035] 1 kg of weighed propellant absorber tablets were added to a kneader, and 15.0 g of PVA fiber was added in three batches (0.05% of the weight of the absorber tablets per batch) for dispersion. After each batch of fiber was added, the mixture was stirred and dispersed for 10 minutes. After uniform dispersion, plasticization was started. After plasticization, the propellant sample was formed using a mold and designated as GX-3.
[0036] Characterization and testing
[0037] (I) Impact strength analysis of PVA propellants with different addition ratios
[0038] Impact strength is used to measure the toughness or resistance to fracture of propellants under high-speed impact, and is a key data point for evaluating the mechanical properties of propellants. The impact strength of four propellants was tested using the simply supported beam method under low-temperature (-40℃), normal-temperature (20℃), and high-temperature (50℃) conditions. Before the low-temperature test, all propellant samples were stored at -40℃ for at least 2 hours, and before the high-temperature test, all propellant samples were stored at 50℃ for at least 2 hours. The test results are shown in Table 1.
[0039] Table 1 Impact resistance test results
[0040]
[0041] Depend on Figure 1 As shown in the schematic diagram, the fibers are distributed along the axial direction of the tubular drug, resulting in a significant improvement in the impact strength test of a simply supported beam subjected to radial impact. At a low temperature of -40℃, the impact strengths of GX-1, GX-2, and GX-3 are 11.85 kJ / m². 2 12.56 kJ / m 2 and 10.81 kJ / m 2 With the addition of PVA fibers, the impact strength first increased and then decreased, with the largest increase observed when the PVA content was 1.0%, representing a 21.47% improvement compared to the blank sample. At room temperature of 20℃, the impact strengths of GX-1, GX-2, and GX-3 were 34.86 kJ / m².2 37.02 kJ / m 2 and 39.78 kJ / m 2 With the addition of PVA fibers, the impact strength increased sequentially, with the largest increase observed when the PVA content was 1.5%, representing a 22.29% improvement compared to the blank sample. None of the samples broke at high temperatures.
[0042] (II) Compressive strength analysis of PVA propellants with different addition ratios
[0043] The compressive strength of four propellants was tested under low temperature (-40℃), normal temperature (20℃), and high temperature (50℃) conditions. The test results are shown in Table 2.
[0044] Table 2 Results of Compression Test
[0045]
[0046] Under the three temperature conditions, the compressive strength of GX-1 and GX-2 was higher than that of GX, and increased sequentially. The compressive strength of GX-3 was lower than that of GX. GX-3 exhibited the largest maximum compressive strain under all three temperature conditions. Overall, GX-2 had the highest compressive strength, at 187.197 MPa, 65.057 MPa, and 29.911 MPa at the three temperatures, representing increases of 2.06%, 3.13%, and 20.25% compared to GX, respectively.
[0047] (III) Combustion performance analysis of PVA propellants with different addition ratios
[0048] The effect of adding PVA fiber on the combustion performance of propellant was studied using a closed-circuit test. Figure 2 The Pt curve of the propellant combustion is given, from Figure 2 It can be seen that the Pt curves of GX-1, GX-2 and GX-3 propellants are all below GX, Pm decreases and tm (the time corresponding to Pm) increases, indicating that the addition of PVA can reduce the maximum combustion pressure.
[0049] Figure 3 The uP curve of the propellant combustion is given, by Figure 3 It can be seen that the uP curves of GX-1, GX-2 and GX-3 propellants are all above GX, indicating that the addition of PVA has increased the burning rate of the propellant to a certain extent and has a certain combustion-supporting effect.
[0050] The combustion curves were all smooth, with no abnormal fluctuations.
[0051] (iv) Analysis of fiber distribution in PVA propellants with different addition ratios
[0052] The broken surface of the propellant was magnified to obtain... Figure 4 , Figure 5 , Figure 6 , Figure 7 As can be seen, the fibers are indeed distributed axially, and can act as a skeleton inside the propellant, connecting the cracks in the propellant and improving the mechanical properties of the propellant.
Claims
1. The application of a polymer-reinforced fiber as a reinforcing material in propellants to improve mechanical properties, characterized in that, The application method is as follows: The polymer reinforcing fiber is polyvinyl alcohol (PVA); Before plasticizing, PVA is uniformly dispersed in the propellant tablet, and then plasticized to obtain the propellant.
2. The application as described in claim 1, characterized in that, The polymer-reinforced fiber is polyvinyl alcohol (PVA), with a single filament length of 3 mm and a single filament diameter of 15 micrometers. The average molecular weight of the raw material, polyvinyl alcohol, is 60,000 to 150,000.
3. The application as described in claim 1, characterized in that, The mass ratio of PVA to the propellant absorber tablet is 0.005:1, 0.010:1, or 0.015:
1.
4. The application as described in claim 1, characterized in that, PVA is added to the tablets in batches before plasticizing and is stirred and dispersed evenly before plasticizing.
5. The application as described in claim 4, characterized in that, The amount of fiber added in each batch shall not exceed 0.05% of the amount of absorbable tablets, and shall be added in at least two batches. The stirring and dispersion time after each batch of fiber is added shall not be less than 10 minutes.
6. The application as described in claim 1, characterized in that, The propellant tablets are NC-NG-RDX nitrate propellant.