A microwave curing resin unit material selection method based on molecular dynamics simulation and quantum chemistry calculation

Abstract

The application provides a method for evaluating the response speed and reaction strength of a resin material microwave curing process, so as to select a resin base element material suitable for microwave curing. The method combines molecular dynamics simulation and quantum chemical calculation, and studies the dynamic change process of the resin under the microwave field by introducing an alternating electric field. Specifically, the reaction energy barrier under the microwave field is simulated from the transition state theory; the influence of the microwave on the chemical reaction rate is clarified from the effective collision theory; and the promotion effect of the microwave on the curing activity of the resin base element material is analyzed from different dimensions. Based on the above steps, a selection method is established with temperature, reaction energy barrier and effective collision probability as criteria. The application overcomes the limitation that traditional instruments and equipment cannot accurately in-situ characterize the microwave reaction, can pre-evaluate the design and synthesis of the microwave curing resin base element material, and thus improves the microwave curing efficiency of the resin base composite material and reduces the production cost.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of material calculation simulation and the field of composite material manufacturing, and particularly relates to the calculation simulation of resin system under microwave field. BACKGROUND

[0002] In recent years, resin-based composites have been increasingly widely used in high-end technology industries such as aviation, aerospace, and automobiles. However, traditional curing processes such as heat pressing tanks and heat ovens, due to their dependence on indirect heating methods based on heat conduction, have problems such as long curing time, low efficiency, high energy consumption, and the like, which have become the main bottleneck restricting the further development of composites. In the production cost of composites, the energy cost accounts for more than 60%, therefore, exploring efficient and low-cost curing technology has become an important direction of research in this field. Microwave curing technology uses microwave radiation to directly heat the interior of the material, and through the dielectric loss of the material itself, the microwave energy is converted into heat energy to achieve rapid and uniform heating, and has the advantages of less energy consumption and rapid curing, and is a new emerging composite material curing process. This technology not only significantly reduces energy consumption and speeds up the curing speed, but also effectively reduces the temperature gradient and residual stress inside the material, thereby improving the overall quality and performance of the material. Therefore, the research and development of microwave curing technology has important significance for improving the production efficiency of composites, reducing energy consumption, improving the quality and performance of materials, and promoting the application and development of composites in various fields.

[0003] Currently, the low microwave response and low microwave reactivity of resin matrix limit the efficiency of microwave curing process. Although previous studies have pointed out that the lack of effective theoretical guidance is a key obstacle to the preparation of high microwave response resin matrix, the existing technology still mainly relies on the addition of microwave absorbers to improve the microwave absorption capacity of the resin matrix. For example, patent CN106633649A uses carbon nanofiber, montmorillonite, carbon nanotube, graphene and other nano fillers as microwave absorbers to improve the microwave response of the resin matrix; patent CN111518368B uses nano materials to modify ionic liquid and amide ionic liquid as additives to improve the microwave curing efficiency of the epoxy system; patent CN114921148B uses carbon black in waste rubber powder and TiO2 in titanium slag to cooperatively absorb electromagnetic waves to improve the microwave curing effect; patent CN113861362B uses fly ash inorganic particles as microwave absorbers to promote the microwave absorption of the system; patent CN111484706B uses tri-substituted imidazole ionic liquid to improve the microwave response of the resin system. It can be found that the current reported microwave curing resin system research mainly focuses on carbon-based nanomaterials, ferromagnetic nanomaterials, ionic liquids and other components as additives to improve their microwave response. Although the above methods are effective to some extent, they also bring problems such as high cost, risk of overheating and explosive polymerization, too large density and viscosity, poor dispersibility and increased difficulty of subsequent finishing, which together limit the large-scale application of microwave curing resin system. In this context, how to accurately determine the microwave response and microwave curing activity of the resin is crucial for in-depth understanding of the curing mechanism and promoting theoretical research. However, existing monitoring technologies, such as infrared thermal imaging, although can provide basic temperature information, are limited by high cost and the need for additional protective measures, making it difficult to achieve accurate in-situ characterization of the curing process. Moreover, due to the high concentration of energy and the uncertainty of the reaction in the microwave curing process, most existing characterization equipment cannot be directly applied to the microwave scene. At the same time, the microwave absorption properties of the resin are determined by the dielectric constant affected by temperature, viscosity, molecular density and polarity, which increases the complexity of the design and preparation of the microwave resin system. In summary, there is currently a lack of a reliable method for selecting microwave curing resin matrix materials. In order to overcome these challenges, the present invention proposes a method for selecting microwave curing resin matrix materials based on molecular dynamics simulation and quantum chemical calculation. This method starts from the perspective of improving the intrinsic microwave response of the resin system, based on non-equilibrium molecular dynamics simulation under microwave field, realizes the quantitative analysis of the response of different matrix materials of the resin in the microwave heating dynamic process; based on the transition state theory and collision theory, the interaction between microwave and resin matrix materials at atomic and molecular levels is accurately described; multi-scale and multi-factor reveals the screening and compounding principle of microwave response and reactive resin matrix, providing important theoretical guidance for predicting the behavior of materials in the microwave field and optimizing the design of new efficient microwave response resin matrix materials. SUMMARY

[0004] In order to solve the above-mentioned deficiencies and bottlenecks in the prior art, the present application is based on the effective collision theory and the transition state theory, and proposes a microwave curing resin matrix material selection method based on molecular dynamics simulation and quantum chemical calculation, which analyzes the effect of microwave on resin system heating and the change of reaction energy barrier under microwave, and provides a thought for the design and synthesis of high microwave responsive resin matrix materials.

[0005] In order to achieve the above purpose, a microwave curing resin matrix material selection method based on molecular dynamics simulation and quantum chemical calculation, the specific technical scheme includes the following steps:

[0006] Step 1. Structure optimization of resin system molecular monomer: (1) starting from the molecular structure of the matrix material to be analyzed, using modeling software to establish the monomer molecular structure model of each component in the resin system, (2) using quantum chemical calculation software to optimize the structure of the monomer molecular structure model to obtain its lowest energy configuration.

[0007] Step 2. Construction of all-atom molecular dynamics model of epoxy resin system: (1) use wave function processing software to obtain the charge of the molecular monomer and correct the charge of the constructed molecular model to construct an accurate and reasonable molecular dynamics monomer model. (2) Use modeling software to construct the box for molecular dynamics simulation of the resin system, the number relationship of resin molecules and curing agent molecules in the box can be represented by the proportion k, where N epoxy is the number of resin molecules, N amine is the number of curing agent molecules, f epoxy is the number of reaction sites on a single resin molecule, f amine is the number of reaction sites on a single curing agent molecule, and the proportion k is set to 0.6-1.5. For a single component simulation system, the box is filled with molecules of the component. (3) Optimize the structure of the box and perform 0.1-5 ns energy minimization, 0.1-10 ns temperature bath and 0.1-10 ns pressure bath to mix the resin system uniformly to meet the needs of subsequent molecular dynamics simulation.

[0008] Step 3. Non-equilibrium kinetic simulation under microwave field: (1) Simulate the effect of microwave on the resin system by applying an alternating electric field of a specified frequency in a specified direction of the model, where the box temperature is set to 273-600 K, the pressure is set to 0-10 atm, and the time step is set to 0.5-5 fs. In order to maintain the stability of the box and the molecular structure, the hydrogen bond length is constrained during the simulation, and these constraints are maintained by the LINCS algorithm. The microwave intensity is set to 0-10 V / nm, the microwave frequency is set to any heating frequency in the range of 300 MHz-300 GHz, and the simulation time is set to where f is the microwave heating frequency. (2) Numerical analysis of the simulation results, including the energy and temperature changes of single-component systems, and the effective collision probability (P) of mixed-component systems.

[0009] Step 4. Quantum chemical calculation under microwave field: (1) Perform structure optimization and single-point calculation on the optimized monomer molecular structure of each component in the system under microwave field, to simulate the transient effect of microwave field on the molecular structure. (2) Align the resin and curing agent molecules in the microwave direction and apply a microwave field to calculate the transition state, to simulate the effect of microwave field on chemical reactions. (3) Statistics on the calculation results, including changes in monomer structure, electronic distribution, band gap (E gap ), dipole moment (Dipole Moment) change, molecular polarity index (MPI), reaction energy barrier (ΔE) change, etc., to evaluate the microwave responsiveness and reactivity of different molecules in the microwave curing process.

[0010] Step 5. Evaluation of resin system microwave responsiveness: (1) By comparing the changes in band gap, dipole moment, and polarity index of resin monomers under different microwave intensities, determine the speed of the monomer's intrinsic response to microwave, with faster changes representing better microwave response. (2) By comparing the changes in temperature and energy after non-equilibrium kinetic simulation under microwave field, determine the strength of the resin system's response to microwave, with faster temperature and energy rises representing better microwave responsiveness.

[0011] Step 6. Evaluation of resin system reactivity under microwave field: (1) By comparing the energy barriers of the transition state of the resin curing agent under microwave field, determine the difficulty of the resin curing agent system's reaction under microwave, with a greater reduction in reaction energy barrier representing a lower difficulty of reaction under microwave, and a higher microwave reactivity. (2) By comparing the effective collision probability between reaction sites during non-equilibrium kinetic simulation under microwave field, determine the difficulty of the reaction of the resin curing agent system under microwave field, with a higher effective collision probability representing a higher probability of reaction under microwave field, and a higher microwave reactivity.

[0012] The modeling software described in step 1 (1) refers to the software for constructing the structure model of a monomer molecule, including but not limited to Gauss View, Materials Studio, Chem 3D, Packmol, etc.

[0013] The quantum chemistry calculation software described in step 1 (2) refers to the software for calculating the electronic structure and energy of a molecule, including but not limited to Gaussian, ORCA, Materials Studio DMol3, etc.

[0014] The structure optimization program in the quantum chemistry calculation described in step 1 (2) uses a basis set and a functional suitable for organic molecule calculation, the functional of the calculation process is selected from but not limited to one of wB97M-V, wB97XD, B3LYP, B3LYP-D3(BJ), M06-2x, PBE0, and the basis set of the calculation process is selected from but not limited to one of 6-31G**, 6-311G**, def-TZVP, def2-TZVP, def2-TZVPD, def2-QZVP.

[0015] The wave function analysis software described in step 2 (1) refers to the software for analyzing the optimized results in step 1 (2), including but not limited to Multiwfn, TopMoD, and the charge correction described here includes but is not limited to Mullikin, RESP, RESP2, etc.

[0016] The molecular dynamics simulation software described in step 2 (2) refers to the software for simulating the evolution of a system over time, including but not limited to Gromacs, Lammps, Amber, NAMD, Materials Studio Forcite, etc.

[0017] The temperature and pressure bath described in step 2 (3) refers to the pretreatment of the resin system model, specifically by adjusting the temperature and pressure of the system, the temperature bath methods used here include but are not limited to V-rescale, Berendsen, Nose-Hoover, Anderson, the pressure bath methods used here include but are not limited to Berendsen, Nose-Hoover, Parrinello-Rahman, and the force field used here includes but is not limited to GAFF, AMBER, DREIDINGlNG, COMPASS, CVFF.

[0018] The introduction of the microwave field described in step 3 (1) is specifically a method of setting an alternating electric field with a cosine waveform in one or more directions along the X, Y, and Z axes, and the formula of the external electric field model is as follows:

[0019]

[0020] where E (0) is the applied electric field strength (ranging from 0 to 10 V / nm), t0is the time of the maximum point of the pulse, s is the pulse width (ranging from 3.33 ns to 3.33 ps), w is the angular frequency of the pulse (ranging from 1.88 x 10 9 rad / s to 1.88 x 10 12 rad / s), t is the simulation time (ranging from 20 to 100 ns), E (t) is the electric field strength at t.

[0021] The temperature and energy change of the single component described in step 3(2) refers to the temperature and energy of the single resin or curing agent component under the microwave field, and the specific method is as follows: the modeling software is used to insert a specified number of monomer molecules in the simulation box to construct the simulation system. Then, the system is subjected to energy minimization, bath, and pressure bath operations in sequence to obtain the initial equilibrium configuration. On this basis, the simulation pressure is kept unchanged, and the aforementioned simulation microwave field is applied, and the corresponding trajectory file is generated. By traversing the trajectory file, the system energy and temperature in each frame are analyzed, and the energy and temperature change curves with time are finally output, so as to obtain the energy and temperature change of the system under the microwave heating simulation condition.

[0022] The effective collision probability of the mixed component system described in step 3(2) refers to the probability that the distance and angle between the reaction sites meet the chemical reaction collision theory to generate new bonds within the simulation time length, and the specific method is as follows: first, the reactive sites on the resin molecules are marked as A, the reactive sites on the curing agent molecules are marked as B, and the distance between A and B is marked as r. The angle between the vector direction of A and B and the adjacent carbon atom is , and the transverse direction is When the distance between A and B is less than r, and the angle is within the range of Figure 1 , the collision is defined as an effective collision as shown in the attached figure, wherein the purple projected area represents the state of effective collision. Then, the trajectory analysis is performed on the system that has been subjected to non-equilibrium dynamics simulation, the trajectory file is traversed by script, the number of all collisions is N total , and the number of effective collisions is N effective , so as to calculate the probability of effective collision The distance and angle here can be set based on literature experience or calculated by quantum chemistry software.

[0023] The way of applying electric field to realize the transient state of the molecule under the simulated microwave field described in step 4 (1) and (2) is that the direction of the electric field is set along / against the direction of the dipole moment to simulate the transient state of the molecule moving with the microwave, and the specific method is as follows: first, the monomer molecule is optimized (opt) and frequency calculated (freq) by using a low-level basis set and a functional, and a stable and non-false frequency configuration is obtained as an initial guess configuration, and the structure coordinates are converted by using Multiwfn software, so that the direction of the dipole moment is aligned along the x axis and saved. Then, the electric field is applied from the positive and negative axes of the x axis by using the field tool, and the geometry optimization and frequency calculation are performed again to obtain the transient state structure optimization and single-point calculation results under the microwave field. Further, in the transition state calculation process, first, the optimized initial guess configuration is analyzed by electrostatic potential (ESP), and the reaction site is determined, and the monomer molecule structure is adjusted to the direction of the dipole moment by using the Multiwfn software. Subsequently, the resin and the curing agent monomer are arranged along the direction of the dipole moment, and the reaction sites are close to The TS method is used for structure optimization to generate an initial guess structure. The TS method is used again for optimization, and the electric field is applied to the initial guess structure from the positive and negative axes of the x axis to obtain a transition state model with a unique false frequency. Finally, the structures of the reactants and products are determined by setting maxpoints to be greater than 100 and executing the IRC command, and the total energy E reactants of the reactants and the total energy E TS of the transition state are calculated by optimizing the structure of the transition state and the reactants and performing single-point calculation, and the difference between the two is the reaction energy barrier (ΔE), so as to determine the reactivity between the resin and the curing agent molecules under the microwave field. The specific method is shown in the accompanying drawings. Figure 2 Electric Field+ and Electric Field- represent that the electric field is set along / against the direction of the dipole moment to simulate the transient change of the molecule moving with the alternating microwave field.

[0024] In the present application, the change of energy and temperature in the single-component non-equilibrium kinetic microwave model in step 3 is used to compare the responsiveness of different systems to microwave heating; the band gap, dipole moment change and molecular polarity index change obtained by quantum chemical calculation of the single molecule under the simulated microwave field in step 4 are used to judge the intrinsic response of the molecule to the microwave; the effective collision probability obtained by the non-equilibrium kinetic microwave simulation of the resin system in step 3 is used to judge the influence of microwave on the probability of chemical reaction; and the change of the transition state reaction level obtained by quantum chemical calculation of the resin system under the simulated microwave field in step 4 is used to compare the influence of microwave on the difficulty of chemical reaction.

[0025] Effects of the present application

[0026] The application provides a microwave curing resin element material selection method based on molecular dynamics simulation and quantum chemistry calculation, the algorithm of simulating a microwave by introducing an alternating electric field is used to study a dynamic change process instead of a static physical quantity, and a transition state theory is supplemented in combination with an effective collision theory to reveal the promotion of the microwave from different dimensions. In addition, the quantum chemistry calculation under the microwave field includes single-point calculation on the optimized molecular structure of each component in the system and transition state calculation on the resin and curing agent molecular system, and the influence of the microwave field on the molecular structure and the reaction path is deeply understood through the calculation, so that solid theoretical support is provided for the experimental results. Compared with the traditional method, the application has the following advantages: (1) high efficiency and accuracy: the method uses cross-scale modeling and calculation software from the molecular scale to the micro-nano scale to accurately simulate the reaction behavior of the material in the microwave curing process, can accurately reflect the influence of the microwave field on the resin material, and improves the screening and evaluation efficiency of the microwave curing resin element material. (2) Cost saving: the method reduces the number of actual experiments and avoids a large number of trial and error processes, thereby saving experimental costs. Efficient simulation and calculation accelerate the material research and development process and improve the research and development efficiency. (3) Performance optimization: quantitative analysis of the microwave responsiveness and reactivity of different resin element materials in the microwave curing process provides detailed data support, which is helpful to optimize the material performance and improve the consistency and reliability of the material performance. (4) Wide applicability: not only suitable for the selection of microwave curing resin element materials, but also suitable for the judgment of the heating performance and reaction activity of small molecules under other microwave fields, and has wide applicability. (5) Theoretical and practical value: the method of the application provides a new idea and tool for the development of microwave curing technology, and has important theoretical and practical application value. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 Schematic diagram of molecular effective collision under a microwave field

[0028] Figure 2 Transition state schematic diagram of quantum chemistry calculation under a microwave field

[0029] Figure 3 Temperature and energy changes of different resin systems simulated under a microwave field for 20 ns

[0030] Figure 4 Quantum chemistry calculation results of different resin molecules under a simulated microwave field: (a) band gap, (b) dipole moment, (c) polarity index DETAILED DESCRIPTION

[0031] The application provides a microwave curing resin element material selection method based on molecular dynamics simulation and quantum chemistry calculation, and the features and performance of the application are further described in detail in combination with the embodiments. Embodiment:

[0032] The selected research objects are as follows: bisphenol A diglycidyl ether (DGEBA) is the most widely used bisphenol A type epoxy resin; hydrogenated bisphenol A diglycidyl ether (H-DGEBA) has no steric hindrance effect of benzene ring compared with DGEBA; triglycidyl p-aminophenol (TGPAP) is an amino three-functional epoxy resin, and 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester is an alicyclic three-functional epoxy resin, which is a representative of structural asymmetry.

[0033] Firstly, the above research objects are modeled by using modeling software Gauss View, and then the model is optimized and single-point calculated at the level of B3LYP / def2-TZVPD by using quantum chemistry calculation software Gaussian.

[0034] Further, the results of single-point calculation are calculated by using wave function processing software RESP2 charge calculation, and the obtained charge value is assigned to the original file as correction. Then, the modeling software Packmol is used to construct the simulation box of the system according to the molar equivalent ratio in the resin system. Here, TGPAP and DETDA are taken as examples, 1 TGPAP has three epoxy group reaction sites, and 1 DETDA has four active hydrogen as reaction sites, so the simulation box with a side length of 1 nm is filled according to the number ratio of 4:3.

[0035] Further, the simulation box is pretreated before microwave simulation by using molecular dynamics simulation software Gromacs, the bath method used here is V-rescale, the pressure bath method used is Parrinello-Rahman, and the force field used is GAFF, and the pretreated system is obtained by successively performing 1 ns of energy minimization, 5 ns of bath, and 5 ns of pressure bath.

[0036] Further, the simulation box of the pretreated system is subjected to non-equilibrium dynamics simulation with an external microwave, the pressure is set to 1 atm, the temperature is set to 300 K, 2.45 GHz is selected as the frequency of the alternating pulse electric field, i.e., the frequency of the simulated microwave field, the direction of the alternating electric field is set to the positive direction along the X axis, the electric field strength of 0.001-1 V / nm is selected as the strength of the microwave heating power, and 20 ns is selected as the microwave simulation time length. The trajectory file obtained by the molecular dynamics simulation is processed, and the temperature and energy of the system within the simulation time length are counted to compare the responsiveness of different resin monomers to microwave heating as shown in the accompanying Figure 3 .

[0037] Further, the distance r between the epoxy group and the amine group reaction site is set to and The setting is 0-20°, and the effective collision is defined within this range. Traverse the length of the non-equilibrium dynamics simulation, and count the proportion of effective collisions in the total number to compare the effects of microwaves on the reactivity of different resin mixture systems, as shown in Table 1.

[0038] Further, according to the previously statistically obtained dipole moment direction, an electric field is applied along / against the dipole moment direction of the epoxy resin monomer, and here 0.0001, 0.0002, 0.0005, 0.001, 0.002, 0.005 a.u. are selected as the point electric field strength, and the energy gap, dipole moment, and polarity index of different monomers are calculated after optimization, as shown in Table 2. Figure 4

[0039] Further, the transition state of the resin and the curing agent monomer under the microwave field is selected for calculation. First, the resin monomer and the curing agent monomer are aligned along the dipole moment direction, and then 0.001 is selected as the electric field strength, and the energy barrier of different monomers under the microwave is calculated, as shown in Table 2.

[0040] In order to verify that this method can well show the responsiveness and reactivity of resin base element materials in the microwave curing process, the research objects are as follows: bisphenol A diglycidyl ether (DGEBA), hydrogenated bisphenol A diglycidyl ether (H-DGEBA), trisglycidyl p-aminophenol (TGPAP), and 4,5-epoxycyclohexane-1,2-dicarboxylic acid diglycidyl ester. In order to determine the influence of different resin systems on microwave responsiveness, an infrared thermal imager is used to collect the temperature changes during microwave heating, and a broadband liquid dielectric spectrum is used for characterization, as shown in Table 3. The measured and theoretical calculation trends are consistent, and under the same microwave heating power, TGPAP heats up the fastest and has the largest dielectric loss, which is the best sample in the microwave-responsive resin system. In order to determine the influence of microwaves on the reactivity of the resin system, the mixed system of the resin sample and the curing agent is tested, and the liquid nitrogen quenching off-line sampling method is used to sample the resin curing process, and the infrared spectrum is characterized, and the comparison results of different samples are shown in Table 4. The measured and theoretical calculation results are consistent, and under the same reaction time length, the microwave curing process as a whole presents higher curing activity, and TGPAP has the fastest reaction, which is the best sample in the microwave-reactive resin system.

[0041] ​In conclusion, compared with the conventional scheme, the embodiment of the present application can accurately reflect the responsiveness of various types of resin base materials to microwave heating without the need for expensive equipment and complex experiments, can accurately reflect the reaction activity of resin base materials under microwave, and can more clearly explain the structure-activity relationship between microwave heating responsiveness and microwave reaction activity and resin base materials. Therefore, the present application can be used to guide the selection of resin base materials for microwave curing process, can be used to guide the formula design of microwave curing resin system, and can be used to provide a theoretical basis for the design, synthesis and preparation of resin base materials for microwave curing process.

[0042] The above merely illustrates the preferred embodiments of the present application and is not intended to limit the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

[0043] Table 1. Effective collision probability of different resin systems

[0044]

[0045]

[0046] Table 2. Reaction energy barrier difference of different resin systems

[0047] Resin Grade ΔE (kcal / mol) DGEBA -3.67 DGEAC -4.36 TGPAP -7.97 HDGEBA -2.52

[0048] Table 3. Dielectric constant of glue solution (2.45 GHz) of different resin systems

[0049] Resin Grade Dielectric Constant Dielectric Loss DGEBA 3.67 0.65 DGEAC 4.36 0.76 TGPAP 4.51 0.84 HDGEBA 3.72 0.67

[0050] Table 4. Curing reaction activity of different resin systems

[0051]

[0052]

Claims

1. A method for selecting a microwave-cured resin building block material based on molecular dynamics simulation and quantum chemistry calculation, characterized in that, The method comprises the following steps: (1) structure optimization of resin system molecular monomer: using modeling software to construct the monomer molecular structure model of each component in the resin system, using quantum chemistry calculation software to optimize the molecular structure model, and obtaining the stable configuration with minimum energy; (2) Construction of the full-atom molecular dynamics model of the epoxy resin system: the molecular monomer charge was obtained by using the wave function processing software and was brought into the constructed molecular model for charge correction; the processed resin and curing agent molecular models were placed in a simulation box; then the simulation box was subjected to energy minimization for 0.1-5 ns, warm bath for 0.1-10 ns and pressure bath for 0.1-10 ns in sequence to mix the resin system uniformly; the number ratio of the resin molecules to the curing agent molecules in the box can be represented by a proportion k, wherein N epoxy is the number of resin molecules, N amine is the number of curing agent molecules, f epoxy is the number of reaction sites on a single resin molecule, f amine is the number of reaction sites on a single curing agent molecule, and the proportion k is set in the range of 0.6-1.5; (3) Non-equilibrium dynamics simulation under microwave field: First, the initial temperature of the simulation box of the epoxy system constructed in step (2) is set and the pressure is kept unchanged, then an alternating electric field is applied to the box to simulate the microwave; during the simulation process, the length of the hydrogen bond is constrained, and these constraints are maintained by the LINCS algorithm; the initial temperature of the simulation box is set to 273-600 K, the pressure range is 0-10 atm, and the time step is selected to be 0.1-5 fs; the power of the microwave is set to 0-1000 KW, the direction can be selected along the x, y or z axis or a combination thereof, the microwave frequency is in the range of 300 MHz-300 GHz, and the simulation time is set to (4) quantum chemistry calculation under microwave field: including structure optimization and single-point energy calculation of the molecular monomer of each component in the system, and transition state calculation of the resin and curing agent molecular binary system under microwave field; (5) Resin system microwave response evaluation: by comparing the difference of LUMO and HOMO orbital, i.e. band gap E gap , dipole moment Dipole Moment, and polarity index EPI of different resin monomers under different microwave intensity, and comparing the temperature and energy improvement rate of different resin systems under the same microwave simulation conditions, the response of the resin to microwave is judged. (6) reactivity evaluation of resin system under microwave field: by comparing the high and low of the effective collision probability P of the reaction sites in the resin and curing agent molecules of different resin systems in the same time under microwave simulation, and comparing the high and low of the transition state reaction energy barrier DE of the resin system under microwave field, the reactivity of the resin system under microwave field is judged.

2. The method of claim 1, wherein the method is characterized by, The resin system is composed of a plurality of resins and curing agents, the resins include but are not limited to any one of epoxy resin, acrylic resin, cyanate ester resin, bismaleimide resin, and the curing agents include any one of amine curing agent, acid anhydride curing agent and imidazole curing agent.

3. The method of claim 1, wherein the method is characterized by, The modeling software includes but is not limited to Gauss View, Materials Studio, Chem 3D and Packmol, the wave function processing software includes but is not limited to Multiwfn and TopMoD, the molecular dynamics simulation software includes but is not limited to Gromacs, Lammps, Amber, NAMD and Materials Studio Forcite, and the quantum chemistry calculation software includes but is not limited to Gaussian, ORCA and Materials Studio DMol3.

4. The method of claim 1, wherein the method is characterized by, The force field used in the molecular dynamics simulation of the resin system is selected from but not limited to one of GAFF, AMBER, DREIDINGlNG, COMPASS and CVFF; characterized in that the temperature bath method used in the molecular dynamics simulation includes but is not limited to one of V-rescale, Berendsen, Nose-Hoover and Anderson, and the pressure bath method includes but is not limited to one of Berendsen, Nose-Hoover and Parrinello-Rahman.

5. The method of claim 1, wherein the method is characterized by: The functional of the quantum chemistry calculation process is selected from but not limited to one of wB97M-V, wB97XD, B3LYP, B3LYP-D3(BJ), M06-2x and PBE0, and the basis set of the calculation process includes but is not limited to 6-31G**, 6-311G**, def-TZVP, def2-TZVP, def2-TZVPD and def2-QZVP.

6. The method of claim 1, wherein the method is characterized by: The non-equilibrium dynamics simulation is simulated by applying an alternating electric field of corresponding frequency to simulate microwave, and the applied cosine type alternating electric field is determined by formula wherein E (0) is the applied electric field intensity, the range is set to 0-10 V / nm, t0 is the time of the maximum point of the pulse, σ is the pulse width, the range is set to 3.33 ns-3.33 ps, ω is the pulse angular frequency, the range is set to 1.88×10 9 rad / s-1.88×10 12 rad / s, t is the simulation time, the range is set to 20-100 ns, E (t) is the electric field intensity at t.

7. The method of claim 1, wherein the method is characterized by, The process of energy and temperature change calculation is as follows: first, a specified number of monomer molecules are inserted into the simulation box by using modeling software to construct the simulation system; then, energy minimization, temperature bath and pressure bath operations are sequentially performed on the system to obtain the balanced initial configuration; On this basis, under the condition of keeping the simulated pressure unchanged, the aforementioned simulated microwave field is applied, and a corresponding trajectory file is generated; by traversing the trajectory file, the energy and temperature of the system in each frame are analyzed, and finally the curves of energy and temperature changing with time are output, so that the energy and temperature changes of the system under the microwave heating simulation condition are obtained.

8. The method of claim 1, wherein the method is characterized by: The process of calculating the effective collision probability of the mixed component system is as follows: first, mark the reactive sites on the resin molecules as A, mark the reactive sites on the curing agent molecules as B, and mark the distance between A and B as r; the included angle between the vector direction of A and B and the adjacent carbon atom is θ, the transverse direction is The longitudinal direction is θ; when the distance between A and B is less than r, and the included angle is within the range of θ and , the collision is defined as an effective collision; then, the trajectory analysis is performed on the system which has been subjected to non-equilibrium dynamics simulation, the trajectory file is traversed through script, the number of all collisions is N total , the number of effective collisions is N effective , and thus the probability of effective collision 9. The method of claim 1, wherein the method is characterized by, The process of structure optimization and single-point calculation is as follows: first, the monomer molecule is subjected to geometry optimization opt and frequency calculation freq using a low-level basis set and a functional to obtain a stable and non-virtual frequency configuration as an initial guess configuration for structure optimization; then, the Multiwfn software is used to convert the structure coordinates, align the dipole moment direction of the initial guess structure along the x-axis, and save it as a new structure; then, the field tool is used to apply an electric field to the monomer molecule from the positive and negative directions of the x-axis, and the high-level basis set and the functional are used to perform geometry optimization and frequency calculation on the initial guess structure again, so as to obtain the transient structure optimization and single-point calculation results under the microwave field.

10. The method of claim 1, wherein the method is characterized by: The process of the transition state calculation is as follows: first, the optimized initial guess structure is analyzed by electrostatic potential (ESP), and the functional group with the largest absolute value of electrostatic potential is determined as the reaction site; then, the structure coordinates are converted using Multiwfn software to align the dipole moment direction of the initial guess structure along the x-axis, and saved as a new structure; next, the resin and curing agent monomers are arranged along the dipole moment alignment direction, and the reaction sites determined are brought close to each other Then, the TS method is used to optimize the structure of the arrangement, generating the initial guess structure of the transition state of the reaction between the resin and the curing agent molecules; the field tool is used to apply an electric field to the initial guess structure from the positive and negative axes of the x-axis, and the TS method is used again to optimize the structure, obtaining a transition state model that simultaneously satisfies the conversion conditions between the reactants and products and has a unique imaginary frequency under the microwave field; finally, maxpoints is set to be greater than 100, the IRC command is executed to determine the structures of the reactants and products, and the transition state and the structure of the reactants are optimized and single-point calculated to obtain the total energy E reactants and the total energy E TS of the transition state, and the difference between the two is the reaction energy barrier ΔE, thereby determining the reactivity between the resin and the curing agent molecules under the microwave field.

11. The method of claim 1, wherein the method is characterized by: The statistical analysis of the quantum chemical calculation under the microwave field includes but is not limited to the monomer structure change, electron distribution change, band gap, dipole moment change, molecular polarity index change of the monomer molecule with the change of the microwave field, and the reaction energy barrier change of the reactant molecule with the change of the microwave field; and the statistical analysis of the molecular dynamics simulation under the microwave field includes but is not limited to the energy and temperature change of a single component system and the effective collision probability of a mixed component system.

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