Method and system for measuring curing process of polymer bonded explosive

Abstract

The invention belongs to the related technical field of PBX curing degree measurement, and discloses a method and a system for measuring a curing process of a polymer bonded explosive. Comprising the following steps: acquiring a relative dielectric constant of a to-be-detected polymer-bonded explosive in a curing process, a relative dielectric constant epsilon a of an uncured area volume fraction Va and a relative dielectric constant epsilon c of a completely cured area volume fraction Vc; and obtaining the curing degree (alpha t) of the PBX by adopting the following curing degree calculation formula: # imgabs0 # on the basis of a dielectric constant mixing rule. According to the invention, in-situ and nondestructive measurement of the curing degree of the PBX can be realized, and the anti-interference capability is strong.

Description

Technical Field

[0001] The present invention belongs to the technical field related to the curing process of polymer bonded explosives (PBX), and more specifically, relates to a method and a system for measuring the curing process of polymer bonded explosives. Background Art

[0002] The curing time during the PBX curing process and the crack defects formed during the curing process play a decisive role in the product manufacturing time and service performance. Accurately measuring the curing process of PBX during the forming process and studying the evolution law of the PBX curing process under different influencing factors are of great significance for PBX forming.

[0003] Regarding the measurement of the PBX curing process, how to accurately and non-destructively measure the curing end point of PBX is still an obstacle in this field. Traditional differential scanning calorimetry (DSC), hardness method, hardness method, and rheological method, etc. The hardness method mainly measures the later stage of curing, and the rheological method can usually only measure the degree of curing in the early stage of curing. More importantly, the above methods all require destructive sample preparation and it is difficult to in-situ measure the curing process of PBX during the forming process. Summary of the Invention

[0004] In view of the above defects or improvement requirements of the prior art, the present invention provides a method and a system for measuring the curing process of PBX, which can realize the in-situ measurement of the degree of curing of PBX during the forming process and has strong adaptability.

[0005] To achieve the above object, the technical solutions adopted by the present invention include:

[0006] A method for measuring the curing process of polymer bonded explosives, comprising: obtaining the relative permittivity of the polymer bonded explosives to be measured during the curing process, the volume fraction V a of the relative permittivity ε a of the uncured region and the volume fraction V c of the relative permittivity ε c of the fully cured region;

[0007] The degree of curing α t of the polymer bonded explosives is calculated by the following formula:

[0008]

[0009] Optionally, the relative permittivity of the PBX to be measured during the curing process is obtained in real time;

[0010]

[0011] V a +V c = 1.

[0012] Optionally, the binder participating in the curing in the polymer bonded explosive to be measured is a polymer, and there is an obvious change in the dielectric constant during the curing process;

[0013] The polymers are hydroxyl-terminated polybutadiene, epoxidized hydroxyl-terminated polybutadiene, and hydroxyl-terminated liquid fluororubber.

[0014] A measurement system for the curing process of polymer bonded explosives, which implements the measurement method for the curing process of any polymer bonded explosive described in the present invention, is provided with:

[0015] At least one set of measurement devices for the curing process of PBX materials. Each set of PBX curing process measurement devices includes a pair of parallel plate electrodes, a dielectric constant measurement module, and a PBX curing degree calculation module.

[0016] Optionally, the pair of parallel plate electrodes is used to measure the dielectric constant at the point to be measured. The dielectric constant measurement module is used to transmit the dielectric constant at the point to be measured to the PBX curing degree calculation module. The PBX curing degree calculation module calculates the curing degree α of the PBX to be measured at the point to be measured based on the following curing degree calculation formula t :

[0017]

[0018] The material of the parallel plate electrodes is brass, platinum, or silver.

[0019] The present invention has the following beneficial effects:

[0020] The applicant found that the dielectric method is sensitive to the cross-linking reaction process during the curing process. Therefore, the dielectric method can measure the curing process of PBX. The measurement method has simple steps, obtains the PBX curing degree based on the dielectric constant, is accurate in measurement, is not easily affected by the external environment, has high result stability, and strong universality.

[0021] The parallel plate electrode has a simple structure and is suitable for in-situ and real-time measurement of the PBX curing degree. The melting point of the material of the parallel plate electrode is significantly higher than the PBX curing temperature, and the structure is stable, and it can maintain uniform stability for a long time. Description of the Drawings

[0022] The drawings are used to provide a further understanding of the present disclosure, and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present disclosure, but do not constitute a limitation to the present disclosure. In the drawings:

[0023] Figure 1 is a schematic structural diagram of the PBX curing degree measurement system according to the embodiment of the present application;

[0024] Figure 2 is a schematic diagram of the application scenario of the parallel plate electrode according to the embodiment of the present application;

[0025] Figure 3 are the capacitance measurement results of the first embodiment of this application;

[0026] In all the drawings, the same reference numerals are used to represent the same elements or structures, where:

[0027] 100 - parallel plate electrode; 200 - dielectric constant measurement module; 300 - PBX curing degree calculation module; 400 - PBX charge; 500 - mold. Detailed implementation manners

[0028] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0029] The present invention provides a method for measuring the curing process of PBX, including: obtaining the relative dielectric constant of the polymer bonded explosive to be measured during the curing process, the relative dielectric constant ε of the volume fraction V of the uncured region a and the relative dielectric constant ε of the volume fraction V of the fully cured region a and V of the fully cured region c After measuring the relative dielectric constant of the polymer, the curing degree α can be calculated according to the curing degree calculation formula c : After measuring the relative dielectric constant of the polymer, the curing degree α can be calculated according to the curing degree calculation formula t :

[0030]

[0031] Obtain the relative dielectric constant of the PBX to be measured in real time during the curing process;

[0032]

[0033] V a +V c = 1;

[0034] The polymer in the PBX to be measured is a polar polymer, such as hydroxyl-terminated polybutadiene (HTPB), epoxidized hydroxyl-terminated polybutadiene (EHTPB), and hydroxyl-terminated liquid fluororubber (HTHF-800).

[0035] Combined with Figure 1, the present invention also provides a measurement system for implementing the above-mentioned PBX curing process measurement method, including: at least one set of PBX degree of cure measurement devices, each set of PBX degree of cure measurement devices including a pair of parallel plate electrodes 100, a relative permittivity measurement module 200, and a PBX degree of cure calculation module 300; wherein, the pair of parallel plate electrodes 100 is used to measure the relative permittivity at the measurement point, the relative permittivity measurement module 200 is used to transmit the relative permittivity at the measurement point to the PBX degree of cure calculation module 300, and the PBX degree of cure calculation module 300 is used to calculate the degree of cure α of the PBX at the measurement point based on the following degree of cure calculation formula t .

[0036] The relative permittivity of PBX during the curing process is composed of the relative permittivity ε of the cured area c and the relative permittivity ε of the uncured area a together. After measuring the relative permittivity of the polymer , the degree of cure α can be calculated according to the degree of cure calculation formula t :

[0037]

[0038] The PBX degree of cure measurement device further includes the pole piece material. The material of the parallel plate electrodes is a conductive material, such as brass, platinum or silver. When selecting the pole piece material, a compatibility test with PBX needs to be carried out. As Figure 1 shown, since the parallel plate electrodes 100 used in the PBX degree of cure measurement device need to be in contact with PBX, it is necessary to select a material with good compatibility with PBX to make the parallel plate electrodes.

[0039] Example 1:

[0040] The PBX curing process measurement method of the present invention includes: obtaining the relative permittivity of PBX during the curing process the relative permittivity ε of the cured area c and the relative permittivity ε of the uncured area a . The relative permittivity of PBX is composed of the relative permittivity ε of the cured area c and the relative permittivity ε of the uncured area a together. After measuring the relative permittivity of the polymer , the degree of cure α can be calculated according to the degree of cure calculation formula t :

[0041]

[0042] Measure the crosslinking and curing reaction process of the polymer in PBX. The polymer in this embodiment is HTPB.

[0043] The measurement system of this embodiment is as Figure 1 shown. Each set of PBX degree of cure measurement devices includes a pair of parallel plate electrodes 100, a dielectric constant measurement module 200, and a PBX degree of cure calculation module 300. Among them, the pair of parallel plate electrodes 100 is used to measure the dielectric constant at the measurement point, the dielectric constant measurement module 200 is used to transmit the dielectric constant at the measurement point to the PBX degree of cure calculation module 300, and the degree of cure calculation module 300 is used to calculate the degree of cure (α t ) of the PBX to be measured at the measurement point based on the following degree of cure calculation formula:

[0044]

[0045] As Figure 2 shown, this embodiment uses the forming process of the PBX charge 400 in the mold 500 to measure the degree of cure of PBX.

[0046] S1: Arrange the parallel plate electrodes 100 on the inner wall of the mold 500 and make the parallel plate electrodes 100 protrude from the inner wall of the mold; install the parallel plate electrodes on the inner wall of the mold 500 and make the parallel plate electrodes 100 protrude from the inner wall of the mold 500. Specifically, use brass electrodes so that the surface of the parallel plate electrodes 100 slightly protrudes from the mold plane. Specifically, install a pair of parallel plate electrodes on the inner wall of the mold 500, which can ensure the contact between the parallel plate electrodes and the PBX material. The PBX cures in the mold, and the measured dielectric constant value also changes accordingly. Collect the output dielectric value of the dielectric constant measurement module 200 at regular intervals according to the preset sampling period to obtain the dielectric constant of PBX at the measurement point.

[0047] S2: Use the PBX degree of cure calculation module 300 to calculate the degree of cure at the corresponding point based on the dielectric constant collected by the parallel plate electrodes.

[0048] In summary, the PBX degree of cure measurement method and measurement system provided by the present invention can realize the measurement of the degree of cure of PBX in the plane and thickness directions, with strong anti-interference ability, and is very suitable for industrial preparation and application.

[0049] Repeat the above embodiment four times in parallel, and the capacitance measurement results are as shown in the appendix Figure 3 shown. The results show that when the test time is the same, the deviation of the capacitance values between different repeated batches is less than 5%. In addition, convert the measurement results of this embodiment into the degree of cure. The degree of cure of this embodiment at 150,000 seconds is about 88%, which is relatively close to 90% measured by the DSC method, proving the reliability of the method.

[0050] Those skilled in the art can easily understand that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A method for measuring the curing process of polymer bonded explosives, characterized in that: include: Obtain the relative dielectric constant and the volume fraction V of the uncured area of ​​the polymer bonded explosive to be tested during the curing process a The relative dielectric constant ε a and the volume fraction of the fully solidified area V c The relative dielectric constant ε c ; Degree of curing of polymer bonded explosives α t Calculated by the following formula:

2. The method for measuring the curing process of polymer bonded explosive according to claim 1, characterized in that: Real-time acquisition of the relative dielectric constant of the PBX under test during the curing process; V a +V c =1。 3. The method for measuring the curing process of polymer bonded explosive according to claim 1 or 2, characterized in that: The binder involved in the curing of the polymer bonded explosive to be tested is a polymer, and there is an obvious change in dielectric constant during the curing process; The polymer is hydroxyl-terminated polybutadiene, epoxidized hydroxyl-terminated polybutadiene and hydroxyl-terminated liquid fluororubber.

4. A polymer bonded explosive solidification process measurement system, characterized in that: To implement the method for measuring the curing process of polymer bonded explosives as described in any one of claims 1 to 3, the following steps are provided: At least one set of PBX material curing process measuring devices, each set of PBX curing process measuring devices comprising a pair of parallel plate electrodes (100), a dielectric constant measuring module (200) and a PBX curing degree calculating module (300).

5. The polymer bonded explosive solidification process measurement system according to claim 4, characterized in that: The pair of parallel plate electrodes (100) is used to measure the dielectric constant at the point to be measured, and the dielectric constant measurement module (200) is used to transmit the dielectric constant at the point to be measured to the PBX curing degree calculation module (300), and the PBX curing degree calculation module (300) calculates the curing degree α of the PBX to be measured at the point to be measured based on the following curing degree calculation formula: t :

6. The polymer bonded explosive curing process according to claim 4, characterized in that: The material of the parallel plate electrode (100) is brass, platinum or silver.

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