Method and system for evaluating mechanical properties of aromatic heterocyclic polymers based on molecular simulation

Abstract

The application discloses a method and system for evaluating mechanical properties of aromatic heterocyclic polymers based on molecular simulation, which comprises the following steps: constructing a first structure model of a target aromatic heterocyclic polymer based on structural characteristic parameters of the target aromatic heterocyclic polymer; performing configuration relaxation simulation of the first structure model in NPT and NVT ensembles to obtain a second structure model in a dynamically fully balanced state; applying uniaxial tensile stress to the second structure model and performing configuration relaxation simulation in the NPT ensemble to obtain a third structure model in uniaxial tensile orientation; applying increasing tensile stress to the orientation direction of the third structure model and performing uniaxial tensile mechanical property simulation calculation to obtain an evaluation result of the mechanical properties of the target aromatic heterocyclic polymer. In this way, the mechanical properties of different structural aromatic heterocyclic polymer fibers can be evaluated quickly and efficiently.

Description

Technical Field

[0001] This application relates to the field of polymer simulation technology, and in particular to a method and system for evaluating the mechanical properties of aromatic heterocyclic polymers based on molecular simulation. Background Technology

[0002] Aromatic heterocyclic polymer fibers are a class of high-performance fibers characterized by lightweight, high strength, high modulus, and high heat resistance, finding wide applications in bulletproof protection and aerospace. They include aromatic heterocyclic polyamides (heterocyclic aramids), poly(p-phenylenebenzoxadiazole) (PBO), and aromatic polyimides (PI). With the rapid development of my country's national defense and aerospace industries, there is an urgent need to synthesize and prepare new aromatic heterocyclic polymer fiber materials with higher performance. Traditional experimental methods involve a long process from polymer synthesis to fiber processing, which is susceptible to various influences such as processing conditions and temperature, resulting in poor repeatability and time consumption.

[0003] Existing techniques typically calculate mechanical property evaluation parameters such as tensile fracture strength and modulus by establishing a three-dimensional crystallographic model. However, establishing a three-dimensional crystallographic model requires first resolving the polymer's unit cell structure through experiments such as single-crystal diffraction, which is not applicable to unknown new structural systems. Therefore, existing methods are not suitable for simulating novel heterocyclic aramid fiber materials with unknown structures. Summary of the Invention

[0004] This application provides a method, system, device, and storage medium for evaluating the mechanical properties of aromatic heterocyclic polymers based on molecular simulation. This method can quickly and efficiently evaluate the mechanical properties of aromatic heterocyclic polymer fibers with different structures, without being limited by experimental conditions or affected by human factors.

[0005] To achieve the above objectives, the technical solution of this invention is as follows:

[0006] In a first aspect, embodiments of the present invention provide a method for evaluating the mechanical properties of aromatic heterocyclic polymers based on molecular simulation, comprising: constructing a first structural model of the target aromatic heterocyclic polymer based on the structural characteristic parameters of the target aromatic heterocyclic polymer; performing configurational relaxation simulations of the first structural model using NPT and NVT ensembles to obtain a second structural model in a fully kinetically balanced state; applying uniaxial tensile stress to the second structural model and performing configurational relaxation simulations of the NPT ensemble to obtain a third structural model with uniaxial tensile orientation; applying incremental tensile stress to the orientation direction of the third structural model and performing uniaxial tensile mechanical property simulation calculations to obtain the mechanical property evaluation results of the target aromatic heterocyclic polymer.

[0007] In some possible implementations, the structural characteristic parameters of the target aromatic heterocyclic polymer include at least the repeating unit, single-chain structure, structural parameters, and formulation components of the target aromatic heterocyclic polymer; based on the structural characteristic parameters of the target aromatic heterocyclic polymer, a first structural model of the target aromatic heterocyclic polymer is constructed, including: drawing a repeating unit model of the target aromatic heterocyclic polymer, and building a single-chain structure of the target aromatic heterocyclic polymer based on the repeating unit model; based on the single-chain structure, a first structural model is constructed according to the preset structural parameters and formulation components.

[0008] In some possible implementations, the temperature and time for configurational relaxation simulations of the NPT and NVT ensembles are determined based on the composition of the target aromatic heterocyclic polymer.

[0009] In some possible implementations, a uniaxial tensile stress is applied to the second structural model, and a configurational relaxation simulation of the NPT ensemble is performed to obtain a third structural model with uniaxial tensile orientation. This includes: applying compressive stress of the same magnitude to the X-axis and Y-axis of the second structural model, and performing a configurational relaxation simulation of the NPT ensemble to obtain a third structural model with uniaxial tensile orientation and Z-axis elongation.

[0010] In some possible implementations, incremental stress is applied to the orientation direction of the third structural model, and uniaxial tensile mechanical property simulation calculations are performed to obtain the mechanical property evaluation results of the target aromatic heterocyclic polymer. This includes: obtaining the critical bond-breaking length of the repeating units in the first structural model; applying incremental tensile stress to the third structural model along the Z-axis; wherein the tensile stress increases at preset time intervals; calculating the stress value and elongation rate of the third structural model at each preset time interval until the bond length in the molecular chain of the third structural model elongates to the critical bond-breaking length, and obtaining the tensile stress-strain curve of the third structural model; and determining the mechanical property evaluation results of the target aromatic heterocyclic polymer based on the stress-strain curve.

[0011] In some possible implementations, the mechanical property evaluation results of the target aromatic heterocyclic polymer are determined based on the stress-strain curve, including: taking the maximum stress value in the stress-strain curve as the tensile fracture strength of the target aromatic heterocyclic polymer; and calculating the initial modulus of the target aromatic heterocyclic polymer using a preset strain function based on the tensile stress-strain curve.

[0012] In some possible implementations, the preset strain function is expressed as:

[0013]

[0014] Where E is the initial modulus of the target aromatic heterocyclic polymer, σ 1％ The stress corresponding to 1% strain is expressed in GPa.

[0015] Secondly, embodiments of the present invention provide a molecular simulation-based mechanical property evaluation system for aromatic heterocyclic polymers, comprising: a model building module for constructing a first structural model of the target aromatic heterocyclic polymer based on its structural characteristic parameters; a configuration relaxation module for performing configuration relaxation simulations of the first structural model using NPT and NVT ensembles to obtain a second structural model in a fully kinetically balanced state; a kinetic equilibrium module under uniaxial tensile stress for applying uniaxial tensile stress to the second structural model and performing configuration relaxation simulations of the NPT ensemble to obtain a third structural model with uniaxial tensile orientation; and a calculation and analysis module for applying incremental tensile stress to the orientation direction of the third structural model and performing uniaxial tensile mechanical property simulation calculations to obtain the mechanical property evaluation results of the target aromatic heterocyclic polymer.

[0016] Thirdly, embodiments of the present invention provide an electronic device, including: a memory for storing executable instructions; and a processor for implementing the method provided in the first aspect of the present invention when executing the executable instructions or computer program stored in the memory.

[0017] Fourthly, the present invention provides a computer-readable storage medium storing executable instructions for implementing the method provided in the first aspect of the present invention when executed by a processor.

[0018] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0019] In this embodiment of the invention, a first structural model of the target aromatic heterocyclic polymer is constructed based on its structural characteristic parameters. Configurational relaxation simulations using NPT and NVT ensembles are performed on the first structural model to obtain a second structural model in a fully kinetically balanced state. Uniaxial tensile stress is applied to the second structural model, and configurational relaxation simulations using the NPT ensemble are performed to obtain a third structural model with uniaxial tensile orientation. Increasing tensile stress is applied to the orientation direction of the third structural model, and uniaxial tensile mechanical property simulation calculations are performed to obtain the mechanical property evaluation results of the target aromatic heterocyclic polymer. Thus, without being limited by experimental conditions or influenced by human factors, the mechanical properties of aromatic heterocyclic polymer fibers with different structures can be evaluated quickly and efficiently. Compared with other models, the calculated tensile strength and initial modulus are closer to the experimental values. Attached Figure Description

[0020] To more clearly illustrate the embodiments of the present invention, the accompanying drawings used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 A schematic flowchart of an embodiment of a method for evaluating the mechanical properties of aromatic heterocyclic polymers based on molecular simulation, provided for the implementation of this invention;

[0022] Figure 2 This is a schematic diagram of the third structural model in an embodiment of the present invention;

[0023] Figure 3 This is a schematic diagram of the simulation results of the critical bond-breaking length of the repeating unit model of the target aromatic heterocyclic polymer in the embodiments of the present invention;

[0024] Figure 4 This is a schematic diagram of the tensile stress-strain curve in an embodiment of the present invention;

[0025] Figure 5 This is a schematic diagram of the structure of a molecular simulation-based mechanical property evaluation system for aromatic heterocyclic polymers in an embodiment of the present invention;

[0026] Figure 6 This is a schematic diagram of an electronic device structure according to an embodiment of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0028] In the relevant descriptions of this embodiment, the terms "including," "containing," and "possessing" are all open terms and are generally understood to include but not be limited to; the term "at least one" is generally understood to mean one or more, where "multiple" refers to two or more; the term "at least one of the following" or similar expressions refer to any combination of these items, including any combination of single or multiple items, for example, "at least one of a, b, or c", or "at least one of a, b, and c", which can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple; the symbol "A / B" is used to describe the selection relationship of associated objects, generally indicating an "or" relationship.

[0029] In the following description of the embodiments, the terminology used in the embodiments of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms "a" and "the" as used in the embodiments of this application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0030] Those skilled in the art should understand that, in the following description of the embodiments of this application, the sequence of numbers does not imply the order of execution. Some or all steps may be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0031] Those skilled in the art will understand that the numerical ranges in the embodiments of this application should be understood to specifically disclose each intermediate value between the upper and lower limits of the range. Any stated value or intermediate value within a stated range, as well as any other stated value or each smaller range between intermediate values ​​within a range, are also included within this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0032] Unless otherwise stated, the technical / scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. While this application describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this application. All references to this specification are incorporated by way of citation to disclose and describe the methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0033] To illustrate the technical solution of the present invention, specific embodiments are described below.

[0034] Aromatic heterocyclic polymer fibers are a class of high-performance fibers characterized by lightweight, high strength, high modulus, and high heat resistance, finding wide applications in bulletproof protection and aerospace. They include aromatic heterocyclic polyamides (heterocyclic aramids), poly(p-phenylenebenzoxadiazole) (PBO), and aromatic polyimides (PI). With the rapid development of my country's national defense and aerospace industries, there is an urgent need to synthesize and prepare new aromatic heterocyclic polymer fiber materials with higher performance. Traditional experimental methods involve a long process from polymer synthesis to fiber processing, which is susceptible to various influences such as processing conditions and temperature, resulting in poor repeatability and time consumption.

[0035] Existing techniques typically calculate mechanical property evaluation parameters such as tensile fracture strength and modulus by establishing a three-dimensional crystallographic model. However, establishing a three-dimensional crystallographic model requires first resolving the polymer's unit cell structure through experiments such as single-crystal diffraction, which is not applicable to unknown new structural systems. Therefore, existing methods are not suitable for simulating novel heterocyclic aramid fiber materials with unknown structures.

[0036] Based on this, embodiments of the present invention provide a method for evaluating the mechanical properties of aromatic heterocyclic polymers based on molecular simulation, which can quickly and efficiently evaluate the mechanical properties of aromatic heterocyclic polymer fibers with different structures without being limited by experimental conditions or affected by human factors.

[0037] Figure 1 A schematic flowchart illustrating an embodiment of a molecular simulation-based method for evaluating the mechanical properties of aromatic heterocyclic polymers provided for the implementation of this invention is shown below. Figure 1 As shown, the above-mentioned method for evaluating the mechanical properties of aromatic heterocyclic polymers based on molecular simulation may include:

[0038] S101, Based on the structural characteristic parameters of the target aromatic heterocyclic polymer, the first structural model of the target aromatic heterocyclic polymer is constructed;

[0039] The target aromatic heterocyclic polymers may include, but are not limited to, 4,4'-diphenyl ether diamine (4,4'-ODA), p-phenylenediamine (PDA), o-chloro-p-phenylenediamine (PDA-Cl), 2-(4-aminophenyl)-5-aminobenzoxazole (BOA), and 2-(4-aminophenyl)-5-aminobenzimidazole (PABZ), as well as combinations of pyromellitic dianhydride (PMDA), 3,3,4,4-biphenyltetracarboxylic dianhydride (BPDA), terephthaloyl chloride (TPC), and biphenyl dicarboxylic chloride (BPC).

[0040] In some embodiments, the structural characteristic parameters of the target aromatic heterocyclic polymer may include at least the repeating units, single-chain structure, structural parameters, and formulation components of the target aromatic heterocyclic polymer. Step S101 specifically may include:

[0041] The repeating unit model of the target aromatic heterocyclic polymer is drawn using dedicated modeling software, such as Materials Studio (MS). Then, based on the repeating unit model, a linear polymer is constructed using tools provided by the modeling software, such as `build`, by inputting the number of repeating units to obtain the single-chain structure of the target aromatic heterocyclic polymer. The constructed single-chain structure can then be further optimized using the Forcite molecular dynamics calculation module to obtain the minimum energy conformation of the polymer molecular chain. Finally, based on the optimized single-chain structure, a model box containing a certain number of aromatic heterocyclic polymer single-chain structures can be built using model building tools; this is the first structural model described above.

[0042] The number and quantity of repeating units in the target aromatic heterocyclic polymer molecular chain can be selected based on the needs of the actual application, and this embodiment of the invention does not impose specific limitations on this. Any existing modeling tool can be used, such as the Amorphous Cell module. The Amorphous Cell module is a tool for building amorphous models using the Monte Carlo method. It can be used to build polymer blend models, solution models, composite material models, solid-liquid / solid-gas interface models, pore-filling models, nematic liquid crystal models, etc., with multiple components and different ratios, and plays an important auxiliary role in simulation work in the fields of plastics, glass, food, chemicals, and composite materials.

[0043] S102, Perform configuration relaxation simulations of the first structural model using NPT and NVT ensembles to obtain the second structural model in a fully dynamic equilibrium state;

[0044] In some embodiments, before performing step S102 above, the first structural model may be further optimized.

[0045] For example, taking the Amorphous Cell module as the model building tool, after obtaining the first structural model, the model box built by the Amorphous Cell module can be structurally optimized through the molecular dynamics calculation module Forcite.

[0046] In some embodiments, the temperature and time for configurational relaxation simulations of the NPT and NVT ensembles can be determined based on the composition of the target aromatic heterocyclic polymer.

[0047] It should be noted that the specific temperature and time during the relaxation process can be determined based on the conditions required for the system to reach kinetic equilibrium during the relaxation process. Different target aromatic heterocyclic polymers have different compositions, formulations, and other parameters, and therefore the required temperature and time for the relaxation process can also vary. In this embodiment of the invention, the temperature for each relaxation process can be set between 300K and 800K, and the time can be set between 0.5 and 2 ns.

[0048] For example, configurational relaxation simulations of the NPT and NVT ensembles for the first structural model can be performed by first performing NRT relaxation calculations at 300K for 0.5 to 2 ns, and then performing NVT relaxation calculations at 300K for 0.5 to 2 ns.

[0049] In some embodiments, during the relaxation process, the system may reach a certain local equilibrium state, but this is not necessarily a globally optimal structure. Therefore, in some embodiments, the above method may further include performing configurational relaxation simulations of the first structural model using NPT and NVT ensembles, followed by an annealing process, and then performing configurational relaxation simulations of the NPT and NVT ensembles again.

[0050] For example, firstly, NPT relaxation calculations are performed at 300K for 0.5-2 ns; then, NVT relaxation calculations are performed at 300K for 0.5-2 ns; next, the temperature is increased to 600K-1000K for annealing. Finally, the temperature is lowered to 300K for structural relaxation, using both NPT and NVT at 300K for 0.5-2 ns, thus obtaining a second structural model that is in full dynamic equilibrium. The density of the structural model can be 1.2-1.4 g / m³. 3 .

[0051] Understandably, annealing is a simulation technique that uses a gradual decrease in system temperature to find the optimal structure. During relaxation, the system reaches a local equilibrium state, but this is not necessarily the globally optimal structure. Annealing introduces temperature changes, disrupting this local equilibrium and allowing the system to explore more configuration space, thus finding a structure closer to the global optimum. During relaxation, stress and energy high points may arise due to intermolecular interactions and system constraints. Annealing, by increasing the temperature and then slowly cooling it, promotes molecular motion and rearrangement, leading the system to a more stable, lower-energy state. By introducing the annealing step, the temperature changes that may occur in real physical systems can be better simulated, making the simulation results closer to reality. Furthermore, annealing helps improve the convergence speed and stability of the simulation, allowing the system to reach dynamic equilibrium more quickly.

[0052] S103, apply uniaxial tensile stress to the second structural model and perform configurational relaxation simulation of the NPT ensemble to obtain the third structural model with uniaxial tensile orientation.

[0053] In some embodiments, applying uniaxial tensile stress to the second structural model can be achieved by applying compressive stress of the same magnitude to the X and Y axes of the second structural model, while no stress is applied to the Z axis. In this case, the second structural model under compressive stress is equivalent to being subjected to tensile stress oriented along the Z axis. Then, by performing NPT relaxation on the second structural model under stress, a third structural model with uniaxial tensile orientation and corresponding Z-axis elongation can be obtained.

[0054] For example, the compressive stress can be taken as 1 to 4 GPa, with the same compressive stress applied to the X and Y axes, while no stress is applied to the Z axis. NPT simulations are performed at a temperature of 673 K for a time ranging from 100 to 500 ps.

[0055] In some embodiments, after obtaining the third structural model through step S103, the method may further perform NPT and configurational relaxation simulations of the NVT ensemble on the third structural model, thereby enabling the third structural model to achieve full dynamic equilibrium.

[0056] Understandably, after obtaining the third structural model through step S103, this model may be in a higher energy state, meaning that the interactions between molecules or atoms in the system may not be at their most stable state. Therefore, by performing NPT and NVT relaxation simulations, the system can gradually reach a lower energy, more stable state. NPT relaxation simulations can be performed under constant temperature and pressure conditions, allowing the system to reach equilibrium by adjusting the interactions and positions of molecules. This helps eliminate residual stress in the model, making the molecular arrangement more reasonable and thus closer to the configuration of the real system. Subsequent NVT relaxation simulations can be performed under constant temperature and volume conditions, further adjusting the molecular velocities and positions to achieve kinetic equilibrium while maintaining a constant volume. This helps stabilize the energy state of the system, ensuring that the physical properties tend to stabilize during the simulation process.

[0057] For example, Figure 2 This is a schematic diagram of the third structural model in an embodiment of the present invention. After obtaining the third structural model, NPT relaxation calculations are performed on the third structural model at 300K, with a time of 0.5-2 ns; subsequently, NVT relaxation calculations are performed at 300K, also with a time of 0.5-2 ns. This yields a third structural model that is in full dynamic equilibrium. In this embodiment of the present invention, the density of the structural model is 1.4-1.5 g / m³. 3 .

[0058] S104. Increasing tensile stress is applied to the orientation direction of the third structural model and uniaxial tensile mechanical property simulation calculation is performed to obtain the mechanical property evaluation results of the target aromatic heterocyclic polymer.

[0059] In some embodiments, step S104 above may include:

[0060] S1041, obtain the critical bond-breaking length for breaking the chemical bonds of repeating units in the first structural model;

[0061] The critical bond-breaking length can be calculated using density functional theory. For example, it can be calculated using the flexible sweep function in Gaussian software, where the functional parameter can be B3LYP and the unit can be DNP4.4. (See also...) Figure 3 As shown, Figure 3 This is a schematic diagram illustrating the simulation results of the critical bond-breaking length of the repeating unit model of the target aromatic heterocyclic polymer in an embodiment of the present invention. Figure 3 The target aromatic heterocyclic polymer is the TPC / PABZ polymer of terephthaloyl chloride (TPC) and 5-aminobenzimidazole (PABZ). The critical bond lengths for breaking the chemical bonds of the repeating units can be obtained through flexible sweep simulation calculations using Gaussian software.

[0062] S1042, apply incremental tensile stress to the third structural model along the Z-axis; wherein the tensile stress increases at preset time intervals;

[0063] For example, the tensile stress increases in increments of 0.5 GPa, with an increase of 0.5 GPa every preset time interval. Of course, the magnitude of the tensile stress increase can be any other arbitrary value, determined based on the needs of the actual application. The preset time can be an empirical value, and its specific value is not strictly limited.

[0064] S1043, calculate the stress value and elongation deformation rate of the third structural model at each preset time until the bond length in the molecular chain of the third structural model elongates to the critical bond breaking length, and obtain the tensile stress-strain curve of the third structural model.

[0065] For example, the tensile stress application time can be 3 ps. During this time, within a preset time period, the stress value and elongation rate of the oriented structural model within 3 ps are calculated using the stress-strain calculation script in MS. At the next preset time period, the tensile stress is increased, and the stress value and elongation rate of the oriented structural model within 3 ps are calculated again. This process is repeated until the bond length in the molecular chains of the third structural model elongates to the critical bond breaking length, thereby obtaining the tensile stress-strain curve of the third structural model. See [link to relevant documentation] Figure 4 As shown, Figure 4This is a schematic diagram of the tensile stress-strain curve in an embodiment of the present invention. Figure 4 The target aromatic heterocyclic polymer is a polymer of terephthaloyl chloride (TPC) and 5-aminobenzimidazole (PABZ), namely TPC / PABZ.

[0066] S1044, the mechanical property evaluation results of the target aromatic heterocyclic polymer are determined based on the stress-strain curve.

[0067] Specifically, the maximum stress value in the stress-strain curve is taken as the tensile fracture strength of the target aromatic heterocyclic polymer; based on the tensile stress-strain curve, the initial modulus of the target aromatic heterocyclic polymer is calculated using the strain function.

[0068] The preset strain function can be expressed by the following formula (1):

[0069]

[0070] Where E is the initial modulus of the target aromatic heterocyclic polymer, σ 1％ The stress corresponding to 1% strain is expressed in GPa.

[0071] Thus, through the above step S1044, the tensile fracture strength and initial modulus of the target aromatic heterocyclic polymer can be determined, thereby enabling the evaluation of the mechanical properties of the target aromatic heterocyclic polymer through these parameter values.

[0072] The following specific embodiments illustrate the method for evaluating the mechanical properties of aromatic heterocyclic polymers based on molecular simulation of the present invention.

[0073] Example 1:

[0074] S11. A repeating unit model of TPC / PABZ was drawn using MS software. A linear aromatic heterocyclic polyamide was constructed using the build tool, with 40 repeating units input. The TPC / PABZ molecular chain was established, and structural optimization was performed to obtain the minimum energy conformation of the polymer molecule. Subsequently, an initial structural model box was constructed using the Amorphous Cell module, with 15 polymer molecular chains. A COMPASSII force field was used, and the initial structure density was set to 1.0 g / cm³. 3 .

[0075] S12. The model box built in the Amorphous Cell module was structurally optimized using the Forcite molecular dynamics calculation module. Specifically, NPT relaxation calculations were performed at 300K for 0.5 ns; followed by NVT relaxation calculations at 300K for 1 ns; then annealing was performed at 600K, with NPT and NVT relaxation calculations each taking 2 ns. Finally, the temperature was lowered to 300K for structural relaxation, with both NPT and NVT calculations performed at 300K for 0.5 ns, resulting in a dynamically fully balanced structural model with a density of 1.36 g / cm³. 3 .

[0076] S13. The Barostat module within the Forcite molecular dynamics calculation module was used to perform NPT ensemble simulations on the final L2 structural model under stress. The stress was set to -2 GPa on the X and Y axes, 0 on the Z axis, and the temperature was set to 673 K with an NPT relaxation time of 200 ps. Subsequently, structural relaxation was further performed at 300 K using both NPT and NVT for 1.5 ns, resulting in a uniaxially oriented structural model with fully balanced dynamics and a density of 1.46 g / cm³. 3 .

[0077] S14, using Gaussian software's flexible scanning simulation, the repeating aromatic heterocyclic polymer unit constructed in L1 was calculated, yielding the critical bond length (Lcr) for chemical bond breaking. Then, tensile calculations were performed using the final structural model from MS's stress-strain calculation script L3, with the length of the chemical bond breakage set as... The tensile stress-strain curve of the highly oriented structural model was thus obtained. The tensile fracture strength and initial modulus were then calculated. The tensile fracture strength was determined to be 6.22 GPa, and the initial modulus to be 105.6 GPa.

[0078] Example 2:

[0079] S21. Repeating unit models of TPC / PABZ and TPC / PDA were drawn using MS software. Linear block copolymers were constructed using the build tool, with a repeating unit ratio of TPC / PDA to TPC / PABZ of 1:1 and a total of 45 repeating units. The TPC / PABZ / PDA block copolymer molecular chain was established and its structure optimized to obtain the minimum energy conformation of the polymer molecule. Subsequently, an initial structural model box was constructed using the Amorphous Cell module, with 18 polymer molecular chains. A COMPASS force field was used, and the initial structure density was set to 1.0 g / cm³. 3 .

[0080] S22. The model box built in the Amorphous Cell module was structurally optimized using the Forcite molecular dynamics calculation module. Specifically, NPT relaxation calculations were performed at 300K for 1 ns; followed by NVT relaxation calculations at 300K for 0.5 ns; then annealing was performed at 600K, with NPT and NVT relaxation calculations each taking 1.5 ns. Finally, the temperature was lowered to 300K for structural relaxation, with both NPT and NVT calculations performed at 300K for 1 ns, resulting in a dynamically fully balanced structural model with a density of 1.38 g / cm³. 3 .

[0081] S23. The Barostat module within the Forcite molecular dynamics calculation module was used to perform NPT ensemble simulations on the final L2 structural model under stress. The stress was set to -4 GPa on the X and Y axes, 0 on the Z axis, and the temperature was set to 673 K with an NPT relaxation time of 500 ps. Subsequently, structural relaxation was further performed at 300 K using both NPT and NVT for 2 ns, resulting in a uniaxially oriented structural model with fully balanced dynamics and a density of 1.44 g / cm³. 3 .

[0082] S24, using Gaussian software's flexible scanning simulation, the repeating aromatic heterocyclic polymer unit constructed in L1 was calculated, yielding the critical bond length (Lcr) for chemical bond breaking. Then, tensile calculations were performed using the final structural model from MS's stress-strain calculation script L3, with the length of the chemical bond breakage set as... The tensile stress-strain curve of the highly oriented structural model was thus obtained. The tensile fracture strength and initial modulus were then calculated. The tensile fracture strength was determined to be 7.8 GPa, and the initial modulus to be 158.7 GPa.

[0083] Comparative Example 1:

[0084] The repeating unit model of TPC / PABZ was drawn using MS software. A linear aromatic heterocyclic polyamide was constructed using the build tool, with 40 repeating units input. The TPC / PABZ molecular chain was established, and structural optimization was performed to obtain the minimum energy conformation of the polymer molecule. Subsequently, the initial structural model box was constructed using the Amorphous Cell module, with 15 polymer molecular chains. A COMPASSII force field was used, and the initial structure density was set to 1.0 g / cm³. 3 .

[0085] The model box built in the Amorphous Cell module was structurally optimized using the Forcite molecular dynamics calculation module. Specifically, NPT relaxation calculations were performed at 300 K for 0.5 ns; followed by NVT relaxation calculations at 300 K for 1 ns; then annealing was performed at 600 K, with NPT and NVT relaxation calculations each taking 2 ns. Finally, the temperature was lowered to 300 K for structural relaxation, with both NPT and NVT calculations performed at 300 K for 0.5 ns, resulting in a dynamically fully balanced structural model with a density of 1.36 g / cm³. 3 .

[0086] Using Gaussian software's flexible scanning simulation, the repeating aromatic heterocyclic polymer unit constructed in L1 was calculated, and the critical bond length (Lcr) for chemical bond breaking was obtained as follows: Then, tensile calculations were performed using the final structural model from MS's stress-strain calculation script L3, with the length of the chemical bond breakage set as... The tensile stress-strain curves of the highly oriented structural model were thus obtained. The tensile fracture strength and initial modulus were calculated. The tensile fracture strength was determined to be 2.8 GPa, and the initial modulus to be 32.7 GPa.

[0087] Comparative Example 2:

[0088] A three-dimensional crystallographic model of the TPC / PABZ repeating unit cell was established based on the unit cell parameters. The number of repeating units in the unit cell was 40. The unit cell structure was optimized using the Forcite molecular dynamics calculation module. Using the COMPASSII force field, NPT relaxation calculations were performed at 300 K for 0.5 ns; followed by NVT relaxation calculations at 300 K for 1 ns; then annealing was performed at 600 K, with NPT and NVT relaxation calculations each taking 2 ns. Finally, the temperature was lowered to 300 K for structural relaxation, with both NPT and NVT relaxations performed at 300 K for 0.5 ns, thus obtaining a dynamically balanced structural model with a density of 1.48 g / cm³. 3 .

[0089] Using Gaussian software's flexible scanning simulation, the repeating aromatic heterocyclic polymer unit constructed in L1 was calculated, and the critical bond length (Lcr) for chemical bond breaking was obtained as follows: Then, tensile calculations were performed using the final structural model from MS's stress-strain calculation script L3, with the length of the chemical bond breakage set as... The tensile stress-strain curve of the three-dimensional crystalline structure model was thus obtained. The tensile fracture strength and initial modulus were calculated. The tensile fracture strength was determined to be 43.4 GPa, and the initial modulus to be 263.7 GPa.

[0090] The specific results of Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1 below:

[0091] Table 1:

[0092]

[0093] As shown in Figure 1, the polymer obtained by the present invention has a density of 1.4-1.5 g / m³. 3 The density is close to the actual density of the experimentally prepared fiber (~1.45 g / m³). 3 The simulated mechanical properties, such as tensile breaking strength, range from 3.3 to 7.8 GPa, which is closer to the actual breaking strength of the fiber. Therefore, simulation calculations can guide the development of lightweight, high-strength aromatic heterocyclic polymer fiber materials. Furthermore, the tensile breaking strength determined by existing technologies has a large error compared to the actual value (as shown in Comparative Examples 1 and 2 in Table 1). In this embodiment of the invention, based on the structural characteristic parameters of the target aromatic heterocyclic polymer, a first structural model of the target aromatic heterocyclic polymer is constructed; configurational relaxation simulations of the first structural model using NPT and NVT ensembles are performed to obtain a second structural model in a fully dynamically balanced state; uniaxial tensile stress is applied to the second structural model, and configurational relaxation simulations of the NPT ensemble are performed to obtain a third structural model with uniaxial tensile orientation; incremental tensile stress is applied to the orientation direction of the third structural model, and uniaxial tensile mechanical property simulation calculations are performed to obtain the mechanical property evaluation results of the target aromatic heterocyclic polymer. Thus, without being limited by experimental conditions or affected by human factors, the mechanical properties of aromatic heterocyclic polymer fibers with different structures can be evaluated quickly and efficiently. Compared with other models, the calculated tensile strength and initial modulus are closer to the experimental values.

[0094] Based on the same inventive concept, embodiments of this application also provide a molecular simulation-based mechanical property evaluation system for aromatic heterocyclic polymers. Figure 5 This is a schematic diagram of a molecular simulation-based mechanical property evaluation system for aromatic heterocyclic polymers, as described in an embodiment of the present invention. (See also...) Figure 5 As shown, the molecular simulation-based mechanical property evaluation system 500 for aromatic heterocyclic polymers may include:

[0095] Model building module 501 is used to build a first structural model of the target aromatic heterocyclic polymer based on the structural property parameters of the target aromatic heterocyclic polymer.

[0096] Configuration relaxation module 502 is used to perform configuration relaxation simulations of the first structural model using NPT and NVT ensembles to obtain a second structural model in a fully dynamic equilibrium state.

[0097] The dynamic equilibrium module 503 under uniaxial tensile stress is used to apply uniaxial tensile stress to the second structural model and perform configuration relaxation simulation of the NPT ensemble to obtain the third structural model with uniaxial tensile orientation.

[0098] The calculation and analysis module 504 is used to apply incremental tensile stress to the orientation direction of the third structural model and perform uniaxial tensile mechanical property simulation calculations to obtain the mechanical property evaluation results of the target aromatic heterocyclic polymer.

[0099] In some possible implementations, the structural characteristic parameters of the target aromatic heterocyclic polymer include at least the repeating unit, single-chain structure, structural parameters, and formulation components of the target aromatic heterocyclic polymer; the model building module 501 is also used to draw the repeating unit model of the target aromatic heterocyclic polymer and build the single-chain structure of the target aromatic heterocyclic polymer based on the repeating unit model; based on the single-chain structure, a first structural model is built according to the preset structural parameters and formulation components.

[0100] In some possible implementations, the temperature and time for configurational relaxation simulations of the NPT and NVT ensembles are determined based on the composition of the target aromatic heterocyclic polymer.

[0101] In some possible implementations, the dynamic equilibrium module 503 under uniaxial tensile stress is also used to apply compressive stress of the same magnitude to the X and Y axes of the second structural model and perform configuration relaxation simulation of the NPT ensemble to obtain a third structural model with uniaxial tensile orientation and Z-axis elongation.

[0102] In some possible implementations, the calculation and analysis module 504 is also used to obtain the critical bond-breaking length of the repeating units in the first structural model; apply incremental tensile stress to the third structural model along the Z-axis; wherein the tensile stress increases every preset time interval; calculate the stress value and elongation rate of the third structural model at each preset time interval until the bond length in the molecular chain of the third structural model elongates to the critical bond-breaking length, and obtain the tensile stress-strain curve of the third structural model; and determine the mechanical property evaluation results of the target aromatic heterocyclic polymer based on the stress-strain curve.

[0103] In some possible implementations, the calculation and analysis module 504 is also used to take the maximum stress value in the stress-strain curve as the tensile fracture strength of the target aromatic heterocyclic polymer; and to calculate the initial modulus of the target aromatic heterocyclic polymer by means of a preset strain function based on the tensile stress-strain curve.

[0104] In some possible implementations, the preset strain function is expressed as:

[0105]

[0106] Where E is the initial modulus of the target aromatic heterocyclic polymer, and σ 1％ This represents the stress corresponding to 1% strain, expressed in GPa.

[0107] Based on the same inventive concept, this application provides an electronic device that can be consistent with the molecular simulation-based mechanical property evaluation method for aromatic heterocyclic polymers in one or more of the above embodiments. Figure 6 This is a schematic diagram of an electronic device structure according to an embodiment of the present invention. See also... Figure 6 As shown, the electronic device 600 can use general computer hardware, including a processor 601 and a memory 602.

[0108] In some possible implementations, at least one processor can constitute any physical device having circuitry that performs logical operations on one or more inputs. For example, at least one processor may include one or more integrated circuits, including application-specific integrated circuits, microchips, microcontrollers, microprocessors, all or part of a central processing unit, graphics processing unit, digital signal processor, field-programmable gate array, or other circuitry suitable for executing instructions or performing logical operations. Instructions executed by at least one processor may, for example, be preloaded into memory integrated with or embedded in the controller, or may be stored in separate memory. Memory may include random access memory, read-only memory, hard disk, optical disk, magnetic media, flash memory, other permanent, fixed, or volatile memory, or any other mechanism capable of storing instructions. In some embodiments, at least one processor may include more than one processor. Each processor may have a similar architecture, or processors may have different configurations that are electrically connected or disconnected from each other. For example, processors may be separate circuits or integrated into a single circuit. When more than one processor is used, the processors may be configured to operate independently or collaboratively. Processors may be coupled electrically, magnetically, optically, acoustically, mechanically, or by other means that allow them to interact.

[0109] Based on the same inventive concept, this application provides a computer storage medium storing computer-executable instructions. After being executed by a processor, the computer-executable instructions can realize the molecular simulation-based mechanical property evaluation method for aromatic heterocyclic polymers as described in one or more of the above embodiments.

[0110] The various embodiments in this specification are described in a progressive manner. For the same or similar parts between the various embodiments, please refer to each other. Each embodiment focuses on describing the differences from other embodiments.

[0111] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of this application.

Claims

1. A method for evaluating the mechanical properties of aromatic heterocyclic polymers based on molecular simulation, characterized in that, include: Based on the structural characteristic parameters of the target aromatic heterocyclic polymer, a first structural model of the target aromatic heterocyclic polymer is constructed, including: drawing a repeating unit model of the target aromatic heterocyclic polymer, and building a single-chain structure of the target aromatic heterocyclic polymer based on the repeating unit model; and building the first structural model based on the single-chain structure according to preset structural parameters and formulation components. The first structural model is subjected to configurational relaxation simulations using NPT and NVT ensembles to obtain a second structural model in a fully dynamic equilibrium state. Apply uniaxial tensile stress to the second structural model and perform configurational relaxation simulation of the NPT ensemble to obtain a third structural model with uniaxial tensile orientation; including applying compressive stress of the same magnitude to the X-axis and Y-axis of the second structural model and performing configurational relaxation simulation of the NPT ensemble to obtain a third structural model with uniaxial tensile orientation and Z-axis elongation. Increasing tensile stress is applied to the orientation direction of the third structural model, and uniaxial tensile mechanical property simulation calculations are performed to obtain the mechanical property evaluation results of the target aromatic heterocyclic polymer; including: Obtain the critical bond-breaking length for breaking the chemical bonds of the repeating units in the first structural model; An increasing tensile stress is applied to the third structural model along the Z-axis; wherein the tensile stress increases at preset time intervals. The stress value and elongation deformation rate of the third structural model are calculated within each preset time period until the bond length in the molecular chain of the third structural model is elongated to the critical bond breaking length, and the tensile stress-strain curve of the third structural model is obtained. The mechanical property evaluation results of the target aromatic heterocyclic polymer are determined based on the stress-strain curve.

2. The method according to claim 1, characterized in that, The structural characteristic parameters of the target aromatic heterocyclic polymer include at least the repeating unit, single-chain structure, structural parameters, and formulation components of the target aromatic heterocyclic polymer.

3. The method according to claim 2, characterized in that, The temperature and time for the configurational relaxation simulation of the NPT and the NVT ensemble are determined based on the composition of the target aromatic heterocyclic polymer.

4. The method according to claim 3, characterized in that, The determination of the mechanical property evaluation results of the target aromatic heterocyclic polymer based on the stress-strain curve includes: The maximum stress value in the stress-strain curve is taken as the tensile fracture strength of the target aromatic heterocyclic polymer; Based on the tensile stress-strain curve, the initial modulus of the target aromatic heterocyclic polymer is calculated using a preset strain function.

5. The method according to claim 4, characterized in that, The preset strain function is expressed as follows: in, The initial modulus of the target aromatic heterocyclic polymer. The stress corresponding to 1% strain is expressed in GPa.

6. A system for evaluating the mechanical properties of aromatic heterocyclic polymers based on molecular simulation, characterized in that, include: The model building module is used to construct a first structural model of the target aromatic heterocyclic polymer based on the structural characteristic parameters of the target aromatic heterocyclic polymer; including: drawing a repeating unit model of the target aromatic heterocyclic polymer, and building a single-chain structure of the target aromatic heterocyclic polymer based on the repeating unit model; and building the first structural model based on the single-chain structure according to preset structural parameters and formulation components. The configuration relaxation module is used to perform configuration relaxation simulations of the first structural model using NPT and NVT ensembles to obtain a second structural model in a fully dynamic equilibrium state. The dynamic equilibrium module under uniaxial tensile stress is used to apply uniaxial tensile stress to the second structural model and perform configurational relaxation simulation of the NPT ensemble to obtain a third structural model with uniaxial tensile orientation; including applying compressive stress of the same magnitude to the X-axis and Y-axis of the second structural model and performing configurational relaxation simulation of the NPT ensemble to obtain a third structural model with uniaxial tensile orientation and Z-axis elongation. The calculation and analysis module is used to apply incremental tensile stress to the orientation direction of the third structural model and perform uniaxial tensile mechanical property simulation calculations to obtain the mechanical property evaluation results of the target aromatic heterocyclic polymer; including: obtaining the critical bond-breaking length of the repeating unit in the first structural model; applying incremental tensile stress to the third structural model along the Z-axis; wherein the tensile stress increases at preset time intervals; calculating the stress value and elongation rate of the third structural model at each preset time interval until the bond length in the molecular chain of the third structural model elongates to the critical bond-breaking length, obtaining the tensile stress-strain curve of the third structural model; and determining the mechanical property evaluation results of the target aromatic heterocyclic polymer based on the stress-strain curve.

7. An electronic device, characterized in that, The electronic device includes: Memory, used to store executable instructions; A processor, when executing executable instructions or computer programs stored in the memory, implements the method as described in any one of claims 1 to 5.

8. A computer-readable storage medium storing executable instructions or a computer program, characterized in that, When the executable instructions are executed by the processor, they implement the method as described in any one of claims 1 to 5.

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