Method for determining gel content of four-component composite solid propellant

Abstract

The invention discloses a method for determining the gel content of a four-component composite solid propellant, and belongs to the technical field of chemical analysis, and the method comprises the following steps: preparing a sample; weighing the sample, adding solvent benzene, sealing and storing at normal temperature; standing, taking out for suction filtration, and ventilating to volatilize the solvent; drying and weighing the sample; and calculating to obtain the gel content of the sample. The required experimental equipment is simple, and the operation process is simple, convenient and rapid; the calculated gel content has the advantages of directness and high accuracy. According to the method, the content of the long-term storage four-component composite solid propellant gel is measured by utilizing a normal-temperature balance method, the result error is small, the test cost is low, and the requirement for detecting the content of the long-term storage four-component composite solid propellant gel can be completely met.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical analysis, and particularly relates to a method for determining the gel content of a four-component composite solid propellant. Background Art

[0002] Four-component composite solid propellant (i.e. HTPB propellant) is mainly used as a power source for rocket engines. It is a type of propellant composed of a mixture of polymer binder, solid powder oxidizer, powder metal fuel and other additional components. Chemical reactions will occur in the engine to release energy and provide thrust for the engine. Therefore, the quality stability of the four-component composite solid propellant during storage is crucial. The gel content in the four-component composite solid propellant is not only an important indicator of the quality of a constant propellant, but also the basis for studying its storage aging performance and formulating chemical defense measures. It can provide a basis for predicting the storage life of the propellant and optimizing the formulation. The change in gel content reflects the chemical and physical changes in the storage process of the solid propellant, which is crucial to understanding the propellant aging process and is of great significance for estimating the storage life of the propellant.

[0003] At present, the commonly used gel testing methods are mainly mechanical properties method, activation energy method, Fourier spectroscopy analysis method, and dynamic viscoelastic analysis method. These methods are all indirect methods and require other performance characterizations to understand the existing gel content. The testing process lacks intuitiveness and requires corresponding experimental equipment, and the experimental investment is large. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for determining the gel content of a four-component composite solid propellant.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] A method for determining the gel content of a four-component composite solid propellant comprises the following steps:

[0007] S1. Sample preparation: Cut the long-term stored four-component composite solid propellant into several small tablets for use as samples;

[0008] S2. Weigh 1.5-2.5g of sample into a container, record the mass as m0, add 45-55ml of solvent, seal and store at room temperature;

[0009] S3, after the sample in step S2 is left to stand for 3 to 4 days, it is taken out for suction filtration and ventilated to allow the solvent to evaporate naturally;

[0010] S4, drying the sample in step S3 at 80°C to 85°C, and recording the mass m2 after drying for 2h to 2.5h;

[0011] S5. Calculate the gel content of the sample using the following formula:

[0012]

[0013] m0-sample mass;

[0014] m2-mass after drying;

[0015] η-solid content.

[0016] Preferably, in step S1, the four-component composite solid propellant is cut by a sample making machine, and the size of the small tablets is 10mm*10mm*2mm.

[0017] Preferably, in step S2, the sample is placed in a conical flask, and the solvent is benzene.

[0018] Preferably, in step S3, the solution and the sample are poured into a filtration cup for filtration, and the filtered sample is placed in a fume hood for ventilation.

[0019] Preferably, in step S4, the sample is placed in an oven for drying.

[0020] Compared with the prior art, the present invention has the following technical advances:

[0021] The present invention prepares several small tablets as samples in advance, weighs the samples and places them in solvent benzene for static storage; then takes them out for suction filtration and ventilation to volatilize the benzene, then dries and weighs them; finally, the gel content of the samples is calculated. The content of the long-term storage four-component composite solid propellant gel is determined by the normal temperature equilibrium method, which has the advantages of direct results and high accuracy. The present invention requires simple experimental equipment, simple and fast sample processing technology, small result error, and low testing cost, which can fully meet the needs of long-term storage four-component composite solid propellant gel content detection. DETAILED DESCRIPTION

[0022] The technical solutions in the embodiments of the present invention are clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The present invention provides a method for determining the gel content of a four-component composite solid propellant, comprising the following steps:

[0024] S1. Sample preparation: The four-component composite solid propellant stored for a long time is cut into small tablets by a sample making machine for standby use. The size of the small tablets is 10mm*10mm*2mm. Among them, the sample making machine for making small tablets can be equipped with square billet splitters, peeling machines, slicers and other equipment, and can be completed through remote isolation operation.

[0025] S2. Weigh 1.5-2.5g of sample into a conical flask, record the mass as m0, add 45-55ml of benzene, seal and store at room temperature;

[0026] S3, after the sample in step S2 is left to stand for 3-4 days, it is taken out and poured into a suction filter cup for suction filtration, and then placed in a fume hood for ventilation to allow the benzene to volatilize naturally. The suction filter cup and the fume hood are both prior art and will not be described in detail here.

[0027] S4, putting the sample in step S3 into an oven, drying it at 80°C to 85°C, and recording the mass m2 after drying for 2h to 2.5h;

[0028] S5. Calculate the gel content of the sample using the following formula:

[0029]

[0030] m0-sample mass;

[0031] m2-mass after drying;

[0032] η-solid content.

[0033] The present invention is explained below by means of two specific embodiments.

[0034] Example 1: The solid content of the four-component composite solid propellant to be tested is 87.5% (Formula 1)

[0035] The gel content of the four-component composite solid propellant stored for a long time is determined by the room temperature equilibrium method, which includes the following steps:

[0036] S1. Cut the long-term stored four-component composite solid propellant into standard small blocks of 10mm*10mm*2mm for standby use;

[0037] S2. Weigh 2.0505 g of sample into a conical flask, add 50 ml of benzene, seal and store at room temperature;

[0038] S3. After the sample has been left to stand for 3 days, pour the sample into a filter cup for extraction and wait for the solvent to evaporate naturally;

[0039] S4. Place the sample in an oven for drying at 80°C. After 2 hours of drying, record the mass as 1.8500 g.

[0040] S5. Calculate the gel content of the sample using the formula. The calculation formula is as follows:

[0041]

[0042] 2.0505g-sample mass;

[0043] 1.8500g-mass of sample after drying;

[0044] Solid content - 0.875.

[0045] The above experimental process was repeated five times, and the results obtained are shown in Table 1 below:

[0046] Table 1 Gel content of formula 1 measured by equilibrium method at room temperature

[0047]

[0048] Example 2: The solid content of the four-component composite solid propellant to be tested is 80.5% (Formula 2)

[0049] The gel content of the four-component composite solid propellant stored for a long time is determined by the room temperature equilibrium method, which includes the following steps:

[0050] S1. Cut the long-term stored four-component composite solid propellant into standard small blocks of 10mm*10mm*2mm for standby use;

[0051] S2. Weigh 2.5349 g of sample into a conical flask, add 50 ml of benzene, seal and store at room temperature;

[0052] S3. After the sample has been left to stand for 3 days, pour the sample into a filter cup for extraction and wait for the solvent to evaporate naturally;

[0053] S4. Place the sample in an oven for drying at 80°C. After 2 hours of drying, record the mass as 2.1252 g.

[0054] S5. Calculate the gel content of the sample using the formula. The calculation formula is as follows:

[0055]

[0056] 2.5349 g - sample mass;

[0057] 2.1252g-mass after drying;

[0058] Solid content -0.805.

[0059] The above test was repeated 5 times, and the results are shown in Table 2 below:

[0060] Table 2 Gel content of formula 2 measured by equilibrium method at room temperature

[0061]

[0062] The present invention adopts the principle of similar solvents dissolving each other, selects a suitable solvent benzene, and adopts a normal temperature equilibrium method to soak the sample to be tested. The sample is treated by a single soaking, and after theoretical deduction, a new test method for the gel content of a four-component composite solid propellant stored for a long time is established. The present invention has a simple process, convenient operation, low test cost, simple experimental equipment, can improve the precision and accuracy of the sample gel content, shorten the analysis cycle, and is suitable for large-scale sample testing.

[0063] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of protection of the claims of the present invention.

Claims

1. A method for determining the gel content of a four-component composite solid propellant, characterized in that: The following steps are involved: S1. Sample preparation: Cut the long-term stored four-component composite solid propellant into several small tablets for use as samples; S2. Weigh 1.5-2.5g of sample into a container, record the mass as m0, add 45-55ml of solvent, seal and store at room temperature; S3, after the sample in step S2 is left to stand for 3 to 4 days, it is taken out for suction filtration and ventilated to allow the solvent to evaporate naturally; S4, drying the sample in step S3 at 80°C to 85°C, and recording the mass m2 after drying for 2h to 2.5h; S5. Calculate the gel content of the sample using the following formula: m0-sample mass; m2-mass after drying; η-solid content.

2. The method for determining the gel content of a four-component composite solid propellant according to claim 1, characterized in that: In step S1, a four-component composite solid propellant is cut into small tablets with a size of 10 mm*10 mm*2 mm using a sample making machine.

3. The method for determining the gel content of a four-component composite solid propellant according to claim 2, characterized in that: In step S2, a sample is placed in a conical flask, and the solvent is benzene.

4. The method for determining the gel content of a four-component composite solid propellant according to claim 3, characterized in that: In step S3, the solution and the sample are poured into a filtration cup for filtration, and the filtered sample is placed in a fume hood for ventilation.

5. The method for determining the gel content of a four-component composite solid propellant according to claim 4, characterized in that: In step S4, the sample is placed in an oven for drying.

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