Method for predicting working life of binder system and curing time required by specified curing degree
The curing kinetics of the binder system were studied by non-isothermal DSC method, and a functional model of curing degree and curing time was calculated, which solved the problem of difficult to predict the application period and curing time of the binder system in the prior art, and achieved the optimization of the fluidity of the slurry and the performance of the curing product.
Patent Information
- Application Number
- CN202411489317.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-10-24
- Publication Date
- 2025-03-07
AI Technical Summary
The prior art is difficult to accurately predict the applicable period of the binder system and the curing time required for specified curing degrees, which affects the fluidity, processability and later performance of the cured product.
The curing kinetics of the binder system were studied by non-isothermal DSC method, and the activation energy E, pre-reference factor A and reaction rate constant were calculated, and the functional model of curing degree and curing time was derived, and the curing degree of curing time was calculated at different curing temperatures.
Accurate prediction of the applicable period of the binder system and the curing time required for the specified curing degree is achieved, the fluidity and processability of the slurry are improved, and the later performance of the cured product is optimized.
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Figure CN119580859A_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of solid propellants for cast explosives, and specifically relates to a method for predicting the applicable period of a binder system and the curing time required for a specified curing degree. The present invention experimentally calculates the activation energy E, pre-exponential factor A, and reaction rate constant of the binder system, and derives the functional relationship between the curing degree and the curing time of the binder system at different curing temperatures, in order to achieve the calculation and derivation of the curing degree of the binder system at different curing times at different curing temperatures by establishing a model equation of the curing degree and the curing time. Background Art
[0002] Pot life is one of the most important process parameters in the processing of solid rocket propellants and PBX cast explosives. The pot life of the binder system has a significant impact on the fluidity, processability and later performance of the cured product. Adding different curing agents and catalysts to the binder system will change the reaction rate and thus change the pot life of the system. Therefore, the method of calculating the pot life of the binder system and the curing time required for a specified degree of cure is particularly important.
[0003] In recent years, the multi-scan rate non-isothermal method has become an important research method for thermal analysis kinetics and has been paid attention to by researchers from all over the world. Because differential scanning calorimetry directly measures the change in thermal enthalpy during the curing process, it is easy and fast to operate, has high resolution, and is convenient for quantitative analysis, it has been widely used in the research of thermosetting resin curing. The curing reaction of the HTPB binder system is a continuous exothermic reaction. Therefore, the multi-scan rate non-isothermal method can be used to study the curing process of the system, obtain the curing reaction kinetic equation, and then deduce the curing degree and curing time model equation, so as to realize the calculation of the applicable period of the binder system and the curing time required for a specified curing degree. Summary of the invention
[0004] The present invention provides a method for predicting the applicable period of an adhesive system and the curing time required for a specified degree of curing, which aims to establish a functional relationship between the curing time and the degree of curing during the curing process of the adhesive system, and then calculate the degree of curing of the system at different times, while predicting the applicable period of the adhesive system and the curing time required for a specified degree of curing.
[0005] The present invention is realized by the following technical scheme: a method for predicting the applicable period of an adhesive system and the curing time required for a specified curing degree, using a non-isothermal DSC method to study the curing kinetics of the adhesive system, obtaining the activation energy E, pre-exponential factor A and reaction rate constant of the system through experimental calculation, calculating and deriving a functional model of the curing degree and the curing time, and using the model to calculate the curing degree of the adhesive system at different curing temperatures and different curing times. The specific method is: (1) Conduct non-isothermal DSC experiments on the binder system to obtain the activation energy E and pre-exponential factor A of the binder system; (2) Substitute the activation energy E and pre-exponential factor A of the binder system into the empirical relationship between the Arrhenius rate constant and temperature: , where: k is the rate constant; A is the pre-exponential factor; E is the activation energy; R is the molar gas constant; T is the temperature; According to the above formula, the functional relationship between the system reaction rate constant and the reaction temperature is obtained: a: Rate constant of HTPB / IPDI binder system with TECH as catalyst k The equation for temperature T (K) is: ; Where: k is the rate constant; R is the molar gas constant; T is the temperature; b: Rate constant of HTPB / IPDI binder system with DBTDL as catalyst k The equation for temperature T (K) is: ; Where: k is the rate constant; R is the molar gas constant; T is the temperature; (3) Substitute the reaction rate constant calculated in step (2) into k And the reaction order n is brought into the curing reaction kinetic equation, the differential expression and integral expression of the curing reaction kinetic equation of the binder system are as follows: , the functional relationship between the curing degree and curing time of the binder system is calculated by the above equation: A: The curing reaction kinetic model of HTPB / IPDI binder system with TECH as catalyst is: ; B: The curing reaction kinetic model of HTPB / IPDI binder system with DBTDL as catalyst is: ; Where: a is the degree of curing, t is the curing time, R is the molar gas constant, T is the curing reaction temperature (K).
[0006] In the present invention, when the curing temperature of the binder system is determined, when IPDI is used as a catalyst in TECH or DBTDL, the curing degree at different times can be calculated and estimated by the equation of the curing reaction kinetic model. BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Figure 1 This is the viscosity change curve of IPDI-DBTDL / TECH system (35℃). DETAILED DESCRIPTION
[0008] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments; based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0009] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the disclosure and materials cited therein are hereby incorporated by reference.
[0010] The equivalent techniques of the specific embodiments described that can be understood by routine experiments by those skilled in the art are all included in this application. The experimental methods in the following examples are conventional methods unless otherwise specified. The instruments and equipment used in the following examples are conventional laboratory instruments and equipment unless otherwise specified.
[0011] A method for predicting the pot life of an adhesive system and the curing time required for a specified degree of curing, studying the curing kinetics of the adhesive system using a non-isothermal DSC method, obtaining the activation energy E, pre-exponential factor A and reaction rate constant k of the system through experimental calculation, and calculating and deriving a functional model of the degree of curing and curing time of the system. The degree of curing of the adhesive system at different curing times at different curing temperatures is calculated using the functional model of the degree of curing and curing time.
[0012] The specific method is: (1) Conduct non-isothermal DSC experiments on the binder system to obtain the activation energy E and pre-exponential factor A of the binder system; (2) Substitute the activation energy E and pre-exponential factor A of the binder system into the empirical relationship between the Arrhenius rate constant and temperature [1-4]: , where: k is the rate constant; A is the pre-exponential factor; E is the activation energy; R is the molar gas constant; T is the temperature; According to the above formula, the functional relationship between the system reaction rate constant and the reaction temperature is obtained: a: Rate constant of IPDI system with TECH as catalyst k The equation for temperature T (K) is: ; b: Rate constant of IPDI system with DBTDL as catalyst k The equation for temperature T (K) is: ; (3) Substitute the reaction rate constant calculated in step (2) into kand reaction order n are substituted into the curing reaction kinetic equation. The differential expression and integral expression of the curing reaction kinetic equation of the binder system [5] are as follows: , the functional relationship between the curing degree and curing time of the binder system is calculated by the above equation: A: The curing reaction kinetic model of IPDI system with TECH as catalyst is: ; B: The curing reaction kinetic model of IPDI system with DBTDL as catalyst is: ; Where: a is the degree of curing, t is the curing time, R is the universal gas constant, T is the curing reaction temperature (K).
[0013] Example 1: When the curing temperature of the binder system is determined, the curing degree at different times is calculated and estimated by the curing kinetic equation when IPDI is used as a catalyst with TECH or DBTDL.
[0014] When the curing temperature is 25℃ and 35℃, the estimated values of the curing reaction time t required for different curing degrees a are shown in Table 1 when the IPDI system uses TECH or DBTDL as the catalyst.
[0015] Table 1: Estimated values of curing degree and curing time of IPDI-TECH / DBTDL system From the data in Table 1, we can see that at a certain curing temperature, the degree of curing achieved by the adhesive system after a certain curing reaction time can be clearly estimated. The establishment of this curing reaction model is of great significance for the formulation design of the adhesive system.
[0016] Example 2: Viscosity change of IPDI-DBTDL / TECH binder system under 35°C curing condition: Under the curing temperature of 35°C, the viscosity change of IPDI system with no catalyst and with DBTDL and TECH as catalysts over time was tested. Figure 1 It can be found that after adding catalysts DBTDL and TECH, the viscosity growth of the system is significantly accelerated, and the catalytic effect of DTBDL is more obvious, which is consistent with the test results and estimated results of DSC.
[0017] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
[0018] References: [1] Hu Rongzu, Gao Shengli, Zhao Fengqi, et al. Thermal Analysis Kinetics (Second Edition) [M]. Beijing: Science Press, 2008. [2]Vyazovkin S. Kinetic concepts of thermally stimulated reactions insolids: a view from a historical perspective[J]. International Reviews inPhysical Chemistry, 2000, 19(1): 45-60. [3] Arrhenius S. Über die Reaktionsgeschwindigkeit bei der Inversionvon Rohrzucker durch Säuren[J]. Zeitschrift für physikalische Chemie, 1889,4: 226-248. [4] Flynn JH. The 'temperature integral'-its use and abuse[J]. Thermochimica Acta, 1997, 300(1): 83-92. [5] Liu Zhenhai, Lu Liming, Tang Yuanwang. A Brief Tutorial on Thermal Analysis[M]. Beijing: Science Press, 2012.
Claims
1. A method for predicting the pot life of an adhesive system and the curing time required for a specified degree of curing, characterized in that: The non-isothermal DSC method was used to study the curing kinetics of the binder system. The activation energy E, pre-exponential factor A and system reaction rate constant were obtained through experimental calculation. A curing kinetic model was established, and the model equation of curing degree and curing time was derived. The curing degree of the binder system at different curing temperatures and different curing times was calculated and derived through the model equation of curing degree and curing time.
2. The method for predicting the pot life of an adhesive system and the curing time required for a specified degree of curing according to claim 1, characterized in that: The specific method is: (1) Conduct non-isothermal DSC experiments on the binder system to obtain the activation energy E and pre-exponential factor A of the binder system; (2) Substitute the activation energy E and pre-exponential factor A of the binder system into the empirical relationship between the Arrhenius rate constant and temperature: , where: k is the rate constant; A is the pre-exponential factor; E is the activation energy; R is the molar gas constant; T is the temperature; According to the above formula, the functional relationship between the system reaction rate constant and the reaction temperature is obtained: a: Rate constant of HTPB / IPDI binder system with TECH as catalyst k The equation for temperature T (K) is: ; Where: k is the rate constant; R is the molar gas constant; T is the temperature; b: Rate constant of HTPB / IPDI binder system with DBTDL as catalyst k The equation for temperature T (K) is: ; Where: k is the rate constant; R is the molar gas constant; T is the temperature; (3) Substitute the reaction rate constant calculated in step (2) into k And the reaction order n is brought into the curing reaction kinetic equation, the differential expression and integral expression of the curing reaction kinetic equation of the binder system are as follows: , the functional relationship between the curing degree and curing time of the binder system is calculated by the above equation: A: Function model of curing degree, curing time and curing temperature of HTPB / IPDI adhesive with TECH as catalyst: ; B: Function model of curing degree, curing time and curing temperature of HTPB / IPDI adhesive with DBTDL as catalyst: ; Where: a is the degree of curing, t is the curing time, R is the universal gas constant, T is the curing reaction temperature (K).