Method for simulating polymer materials

Abstract

To provide a method for simulating a polymer material capable of simultaneously taking into consideration the influence of a mechanical force acting on a molecular chain and the chemical reaction between molecules.SOLUTION: Disclosed is a method for simulating a polymer material. This method performs a step S 1 of inputting a molecular chain model modeling a molecular chain of the polymer material into a computer, a step S 2 of inputting a molecular model modeling a molecule for examining reaction with the molecular chain into the computer, an application step S5 in which the computer applies strain or stress to at least the molecular chain model, and a reaction step S6 of calculating the chemical reaction between the applied molecular chain model and the molecular model based on a density functional based tight binding method.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present disclosure relates to a method for simulating polymer materials.

Background Art

[0002] In recent years, as a method for analyzing chemical reactions between molecules, for example, the density functional tight binding method is known. Related technologies include Non-Patent Document 1 and Non-Patent Document 2 below.

Prior Art Documents

Patent Documents

[0003]

Non-Patent Document 1

Non-Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, it is considered that the molecular chains constituting polymer materials such as rubber are undergoing chemical reactions between molecules while being distorted and stressed by mechanical forces. Therefore, in analyzing polymer materials, it is important to consider the influence of mechanical forces and chemical reactions simultaneously.

[0005] The present disclosure has been devised in view of the above actual situation, and the main object thereof is to provide a simulation method for polymer materials that can simultaneously consider the influence of mechanical forces acting on molecular chains and chemical reactions between molecules.

Means for Solving the Problems

[0006] The present disclosure is a simulation method for polymer materials, including a step of inputting a molecular chain model obtained by modeling the molecular chains of the polymer material into a computer, and a step of inputting a molecular model obtained by modeling molecules for examining reactions with the molecular chains into the computer. The computer executes an application step of applying strain or stress to at least the molecular chain model, and a reaction step of calculating a chemical reaction between the applied molecular chain model and the molecular model based on the density functional tight binding method.

Effects of the Invention

[0007] By adopting the above steps, the simulation method for polymer materials of the present disclosure can simultaneously consider the influence of mechanical forces acting on molecular chains and chemical reactions between molecules.

Brief Description of the Drawings

[0008]

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Embodiments for Carrying Out the Invention

[0009] Hereinafter, an embodiment of the present disclosure will be described with reference to the drawings. It should be understood that the drawings include exaggerated expressions and expressions different from the actual structural dimensional ratios in order to assist in understanding the disclosed content. Also, throughout each embodiment, the same or common elements are given the same reference numerals, and duplicate explanations are omitted. Furthermore, the specific configurations shown in the embodiments and the drawings are for understanding the content of the present disclosure, and the present disclosure is not limited to the specific configurations shown.

[0010] In the simulation method of the polymer material of the present embodiment (hereinafter, sometimes simply referred to as the "simulation method"), the chemical reaction between the molecular chain of the polymer material and the molecule is analyzed using a computer. The chemical reaction of the present embodiment is exemplified by oxidation of the molecular chain, but is not limited to such a mode, and may be, for example, vulcanization.

[0011] [Computer] FIG. 1 is a perspective view showing an example of a computer for executing the simulation method of the polymer material. The computer 1 of the present embodiment includes a main body 1a, a keyboard 1b, a mouse 1c, and a display device 1d. In the main body 1a, for example, an arithmetic processing unit (CPU), a ROM, a working memory, a storage device such as a magnetic disk, and disk drive devices 1a1 and 1a2 are provided. In the storage device, software for executing the simulation method of the present embodiment and the like are stored in advance.

[0012] [Polymer Material] The polymer material contains at least one type of molecular chain (polymer). Note that the polymer material may further contain fillers, coupling agents, etc. The molecular chain in this embodiment is exemplified as being butadiene rubber, but is not particularly limited. The molecular chain may be styrene-butadiene rubber, or a molecular chain that does not actually exist at present may be used. Furthermore, the polymer material may contain two or more types of molecular chains.

[0013] [Molecule] The molecule is for examining the reaction with the molecular chain. The molecule is not particularly limited as long as it can react with the molecular chain, and is appropriately selected according to the purpose of analysis. As in this embodiment, when the oxidation of the molecular chain is analyzed, a molecule that oxidizes the molecular chain can be adopted. The molecule that oxidizes the molecular chain contains oxygen or ozone.

[0014] By the way, the molecular chains that make up the polymer material are considered to undergo chemical reactions (such as oxidation) with other molecules while being distorted and stressed by mechanical forces, unlike the molecules used in Non-Patent Document 1, etc. Therefore, when analyzing the polymer material, it is important to consider the influence of mechanical forces and chemical reactions simultaneously. In the simulation method of this embodiment, the state of the polymer material is analyzed (for example, the state of deterioration is evaluated) while considering the influence of mechanical forces acting on the molecular chain and chemical reactions between molecules.

[0015] [Density Functional Tight Binding Method] In this embodiment, the chemical reaction between the molecular chain and the molecule is calculated based on the density functional tight binding method. The density functional tight binding method is a semi-empirical method based on the density functional theory. In the molecular dynamics calculation based on this density functional tight binding method (hereinafter sometimes referred to as "QM / MD calculation"), it is possible to analyze chemical reactions based on quantum mechanics (for example, dynamics involving the generation and cleavage of bonds).

[0016] The outline, calculation conditions, calculation methods, etc. of the density functional tight binding method are known as described in, for example, Non-Patent Document 1 and Non-Patent Document 2. Further, the total number of molecular chains and molecules to be calculated by the density functional tight binding method is set according to, for example, the performance of the computer 1. Note that if the total number is large, the calculation time increases, and there is a risk that the calculation cannot be completed within a realistic time. On the other hand, if the total number is small, there is a risk that the chemical reaction between the molecular chain and the molecule cannot be calculated. From such a viewpoint, it is desirable that the total number be set to about 2 to 500 respectively.

[0017] [Simulation Method of Polymer Material (First Embodiment)] Next, the simulation method of the present embodiment will be described. FIG. 2 is a flowchart showing the processing procedure of the simulation method of the polymer material of the present embodiment. FIG. 3 is a diagram showing a cell 4 in which a molecular chain model 2 and a molecular model 3 are arranged. FIG. 4 is a partially enlarged view of the molecular chain model 2 and the molecular model 3.

[0018] [Input Molecular Chain Model] In the simulation method of the present embodiment, first, a molecular chain model 2 obtained by modeling the molecular chain of the polymer material is input to the computer 1 (step S1). In the present embodiment, as the molecular chain model 2, a butadiene model 2A obtained by modeling butadiene is input.

[0019] The molecular chain model 2 of the present embodiment is defined as an all-atom model. Such an all-atom model can analyze chemical reactions in more detail than, for example, a coarse-grained molecular model (not shown) in which a group of a plurality of atoms is replaced by one bead. As shown in FIG. 4, the molecular chain model 2 of the present embodiment includes a plurality of particle models 5 and bond models 6 that connect between the particle models 5 and 5.

[0020] The particle model 5 is treated as a mass point of the equation of motion in the molecular dynamics calculation described later. That is, parameters such as mass, diameter, charge, or initial coordinates are defined for the particle model 5. The particle model 5 of the present embodiment includes a carbon particle model 5c that models a carbon atom and a hydrogen particle model 5h that models a hydrogen atom.

[0021] The bond model 6 is for restraining between the particle models 5 and 5. The bond model 6 of the present embodiment includes a main chain 6a and a side chain 6b (shown in FIG. 4(a)). The main chain 6a includes, for example, a single bond and a double bond.

[0022] A potential (not shown) that generates an interaction (including repulsive force and attractive force) is defined between adjacent particle models 5 and 5 via the bond model 6. These potentials include, for example, a bond potential, a bond angle potential, and a dihedral angle potential. Such potentials can be appropriately defined based on the description of a patent document (Japanese Patent Laid-Open No. 2018-032077), for example. Thereby, the molecular chain model 2 (in this example, the butadiene model 2A) is defined. The molecular chain model 2 is stored in the computer 1 shown in FIG. 1.

[0023] [Input molecular model] Next, in the simulation method of the present embodiment, a molecular model 3 that models a molecule for examining the reaction with the molecular chain is input to the computer 1 (step S2). In step S2 of the present embodiment, a molecule that oxidizes the molecular chain is modeled. In the present embodiment, an oxygen molecule model 3A that models an oxygen molecule is input, but for example, an ozone molecule model that models ozone may be input.

[0024] The molecular model 3 of the present embodiment is defined as an all-atom model, similar to the molecular chain model 2. Therefore, as shown in FIG. 4, the molecular model 3 includes a plurality of particle models 5 and bond models 6 that connect between the particle models 5, 5. The details of the particle model 5 and the bond model 6 are as described above. In the molecular model 3 (oxygen molecule model 3A) of the present embodiment, the particle model 5 includes an oxygen particle model 5o that models an oxygen atom. The molecular model 3 is stored in the computer 1 shown in FIG. 1.

[0025] [Model Definition Step] Next, in the simulation method of the present embodiment, a polymer material model that models a polymer material is defined (model definition step S3). FIG. 5 is a flowchart showing the processing procedure of the model definition step S3 of the present embodiment.

[0026] [Input Cell] In the model definition step S3 of the present embodiment, first, as shown in FIG. 3, a cell 4, which is a virtual space corresponding to a part of the polymer material, is input to the computer 1 (step S31). The cell 4 of the present embodiment has at least a pair of mutually facing surfaces 7, 7 (in the present embodiment, three pairs of mutually facing surfaces 7, 7). The cell 4 of the present embodiment is defined as a rectangular parallelepiped or a cube (a cube in the present embodiment).

[0027] Periodic boundary conditions are defined for each surface 7, 7 of the cell 4. Thereby, in the molecular dynamics calculation described later, for example, it is possible to perform calculations such that a part of the molecular chain model 2 or the molecular model 3 that has exited from one side surface 7a enters from the other side surface 7b. In FIG. 3, the molecular chain model 2 and the molecular model 3 are shown in a state of protruding from each surface 7, 7. The size of the cell 4 can be appropriately set according to, for example, the total number of the molecular chain model 2 and the molecular model 3 arranged inside the cell 4. The cell 4 is stored in the computer 1 shown in FIG. 1.

[0028] [Arrangement of Molecular Chain Model and Molecular Model] Next, in the model definition step S3 of the present embodiment, the molecular chain model 2 and the molecular model 3 are arranged inside the cell 4 (step S32). In the present embodiment, the molecular chain model 2 and the molecular model 3 are randomly arranged inside the cell 4 so as to be within the above-mentioned total number range (in this example, 2 to 500). The arrangement of the molecular chain model 2 and the molecular model 3 may be performed by the computer 1 or may be implemented by an operator. The cell 4 in which the molecular chain model 2 and the molecular model 3 are arranged is stored in the computer 1 shown in FIG. 1.

[0029] [Definition of Potential] Next, in the model definition step S3 of the present embodiment, as shown in FIG. 4, a potential P1 is defined between adjacent particle models 5, 5 without passing through the bond model 6 (step S33). In the present embodiment, the potential P1 is defined between adjacent particle models 5, 5 without passing through the bond model 6 between adjacent molecular chain models 2, 2, between adjacent molecular models 3, 3, and between adjacent molecular chain models 2 and molecular model 3.

[0030] The LJ potential is adopted for the potential P1 of the present embodiment. With such a potential P1, attractive and repulsive forces can be defined between adjacent particle models 5, 5 without passing through the bond model 6. The LJ potential can be appropriately defined, for example, based on the description in Patent Document (Japanese Unexamined Patent Application Publication No. 2020-086773). The potential P1 is stored in the computer 1 shown in FIG. 1.

[0031] [Calculate Structural Relaxation] Next, in the model definition step S3 of the present embodiment, the initial arrangement of the molecular chain model 2 and the molecular model 3 is relaxed (step S34). In step S34 of the present embodiment, molecular dynamics calculation is performed on the molecular chain model 2 and the molecular model 3 arranged in the cell 4 shown in FIG. 3.

[0032] In molecular dynamics calculations, for example, for cell 4, the Newtonian equations of motion are applied assuming that the molecular chain model 2 follows classical mechanics for a predetermined time. Then, the movement of the particle model 5 at each time is tracked every unit time. Such a calculation of structural relaxation can be processed using, for example, COGNAC included in the Soft Material Comprehensive Simulator (J-OCTA) manufactured by JSOL Corporation.

[0033] In the molecular dynamics calculation of this embodiment, in cell 4, the pressure (for example, 1 atm) and the temperature (for example, 290 K to 305 K) are kept constant (NPT constant). As a result, in step S34, the initial arrangements of the molecular chain model 2 and the molecular model 3 can be relaxed accurately by approximating the molecular motion of the actual polymer material.

[0034] In step S34 of this embodiment, it is desirable to perform molecular dynamics calculations every unit time until the artificial initial arrangements of the molecular chain model 2 and the molecular model 3 are considered to be eliminated. The determination of whether the artificial initial arrangements have been eliminated can be carried out in the same manner as in the prior art. By such relaxation of the initial arrangements, a polymer material model 8 modeling the polymer material can be defined. The polymer material model 8 is stored in the computer 1 shown in FIG. 1.

[0035] [Define calculation conditions] Next, in the simulation method of this embodiment, calculation conditions for performing QM / MD calculations based on the density functional tight binding method are defined in the computer 1 (step S4). The calculation conditions include energy, temperature, volume, pressure, the initial velocity of atoms, and the time step width of MD calculations based on the density functional tight binding method. These calculation conditions are appropriately defined according to the purpose of the analysis. The calculation conditions are stored in the computer 1.

[0036] [Application step] Next, in the simulation method of this embodiment, the computer 1 applies strain or stress to at least the molecular chain model 2 (application step S5). FIG. 6 is a diagram showing the molecular chain model 2 to which strain is applied.

[0037] In the application step S5, if strain or stress is applied to at least the molecular chain model 2, it can be appropriately implemented. In the application step S5 of this embodiment, a uniaxial tensile test for pulling the polymer material model 8 in a predetermined direction (for example, the x-axis direction) is calculated. Such deformation calculation of the polymer material model 8 is based on, for example, the procedure described in Patent Document (Japanese Patent Application Laid-Open No. 2016-081297), and the elongation of the polymer material model 8 is calculated so that one surface 7a and the other surface 7b of the polymer material model 8 are separated from each other.

[0038] The elongation calculation of the polymer material model 8 in this embodiment is calculated based on molecular dynamics calculation, similar to conventional simulations. In this embodiment, the elongation of the polymer material model 8 is calculated until the strain of the polymer material model 8 reaches a predetermined threshold value. The threshold value can be appropriately set (for example, 0.2 to 0.6) according to the purpose of the analysis.

[0039] Due to the elongation of the polymer material model 8 as described above, the molecular chain model 2 disposed therein is elongated in a predetermined direction. Thereby, in the application step S5, strain is applied to the molecular chain model 2 by mechanical force (elongation of the polymer material model 8). The applied molecular chain model 2 (polymer material model 8) is stored in the computer 1.

[0040] In this embodiment, strain is applied to the molecular chain model 2 by calculating the elongation of the polymer material model 8, but it is not limited to such a mode. For example, the contraction of the polymer material model 8 may be calculated so that one surface 7a and the other surface 7b of the polymer material model 8 approach each other. Due to such contraction of the polymer material model 8, stress can be applied to the molecular chain model 2 disposed therein.

[0041] In the application step S5, without performing elongation calculation or shrinkage calculation on the polymer material model 8, for example, the elongation of the molecular chain model 2 may be calculated by directly separating one end and the other end of the molecular chain model 2. Further, the shrinkage of the molecular chain model 2 may be calculated by directly approaching one end and the other end of the molecular chain model 2. Note that for the oxygen molecule model 3A, elongation may or may not be calculated.

[0042] [Reaction step] Next, in the simulation method of the present embodiment, the computer 1 calculates the chemical reaction between the applied molecular chain model 2 and the molecular model 3 based on the density functional tight binding method (reaction step S6). In the reaction step S6 of the present embodiment, QM / MD calculation based on the density functional tight binding method is performed on the molecular chain model 2 and the molecular model 3 included in the elongated polymer material model 8 based on the above calculation conditions.

[0043] In the reaction step S6 of the present embodiment, software capable of performing QM / MD calculation based on the density functional tight binding method is used. The software is, for example, "BIOVIA Materials Studio DFTB+" manufactured by Dassault Systèmes, "DCDFTBMD" manufactured by Cross Ability Co., Ltd., and "DFTB+" of an open source program. At least one of such software is stored in the computer 1.

[0044] Fig. 7(a) is a diagram showing a state in which the molecular chain model 2 is cleaved. Fig. 7(b) is a diagram showing a state in which the cleaved molecular chain model 2 is oxidized.

[0045] As shown in Fig. 7(a), in the QM / MD calculation based on the density functional tight binding method of the present embodiment, a state in which the bond model 6 is cleaved (opened) is calculated between the particle models 5, 5 of the molecular chain model 2 to which stress or strain is applied. In Fig. 7(a), a state in which the main chain 6a of the molecular chain model 2 is cleaved (opened) is shown.

[0046] As shown in FIG. 7(b), in the cleaved molecular chain models 2, 2, oxygen particle models 5o that constitute the oxygen molecule model 3A are respectively bonded. Thereby, in the reaction step S6, the oxidized state (chemical reaction) of the applied molecular chain model 2 is calculated. Such a chemical reaction (oxidation) is promoted by the cleavage of the molecular chain model 2.

[0047] The QM / MD calculation based on the density functional tight binding method may be performed, for example, until the cleavage of the molecular chain model 2 and the chemical reaction between the molecular chain model 2 and the molecular model 3 reach a predetermined state, or until a predetermined calculation time elapses. The calculation results of the chemical reaction are stored in the computer 1.

[0048] Thus, the simulation method of the present embodiment can calculate the state in which the polymer material oxidizes while simultaneously considering the influence of the mechanical force acting on the molecular chain and the chemical reaction between molecules. Thereby, in the present embodiment, unlike the conventional method that cannot consider the influence of the mechanical force, it is possible to simulate the dynamics including the chemical reaction of the polymer material (for example, oxidation promoted by the cleavage of the molecular chain) under the action of the mechanical force. In the present embodiment, as shown in FIGS. 7(a) and (b), it was reproduced that the chemical reaction (oxidation) is promoted by the cleavage of the molecular chain model 2.

[0049] In the reaction step S6, the chemically reacted molecular chain model 2 and the molecular model 3 may be recorded in the computer 1 at predetermined time intervals (for example, the time steps of the MD calculation). Thereby, in the simulation method, it becomes possible to analyze in detail the process (dynamics) of the chemical change between the molecular chain model 2 and the molecular model 3 under the action of the mechanical force.

[0050] [Evaluate the state of deterioration] Next, in the simulation method of the present embodiment, based on the molecular chain model 2 after the reaction step S6, the degradation state of the polymer material is evaluated (step S7). Generally, it is considered that the degradation of the polymer material is caused by the cleavage (cutting) of the molecular chain and the oxidation of the molecular chain. Therefore, in step S7, the degradation state of the polymer material is evaluated based on the total number of cleaved and oxidized portions (hereinafter sometimes simply referred to as "degraded portions") of the molecular chain model 2.

[0051] In step S7 of the present embodiment, when the total value of the degraded portions is smaller than a predetermined threshold value, it is determined that the degradation state of the polymer material is good (difficult to degrade). The threshold value is appropriately set according to, for example, the performance required for the polymer material (such as durability performance, etc.).

[0052] In step S7, when the total value of the degraded portions is smaller than the threshold value, it is determined that the degradation state of the polymer material is good (difficult to degrade) (in step S7, "Yes"). In this case, a product (for example, a tire) including the evaluated polymer material (molecular chain) is manufactured (step S8).

[0053] On the other hand, when the total value of the degraded portions is equal to or greater than the threshold value, it is determined that the degradation state of the polymer material is not good (easy to degrade) (in step S7, "No"). In this case, the structure of the molecular chain is changed (step S9), and steps S1 to S7 are performed again. Thereby, in the simulation method of the present embodiment, it is possible to optimize the polymer material (molecular chain) that is difficult to degrade, and for example, it is possible to reliably manufacture a product with high durability.

[0054] [Simulation Method of Polymer Material (Second Embodiment)] By the way, when strain or stress is applied to the molecular chain model 2, it may be calculated as a molecular chain model 2 having an unstable structure (unstable energy). If such a molecular chain model 2 having an unstable structure is directly used in the reaction step S6, it may take a long time until the calculation converges.

[0055] FIG. 8 is a flowchart showing the processing procedure of the simulation method of the polymer material according to another embodiment of the present disclosure. In this embodiment, for the same configuration as in the previous embodiments, the same reference numerals may be given and the description may be omitted.

[0056] In the simulation method of this embodiment, prior to the reaction step S6, the computer 1 optimizes the structure of the applied molecular chain model 2 based on the molecular orbital method (step S10). In step S10 of this embodiment, based on a known molecular orbital method, the structure of the applied molecular chain model 2 is optimized into a molecular structure having the most stable energy. By using the molecular chain model 2 having such a stable structure in the reaction step S6, it becomes possible to converge the chemical reaction calculation with the molecular model 3 at an early stage. For the optimization calculation based on the molecular orbital method, for example, the quantum chemistry calculation program Gaussian03 manufactured by Gaussian is used. Note that the optimization of the structure of the molecular chain model 2 is not limited to that based on the molecular orbital method, and may be, for example, based on a non-empirical or empirical quantum chemical method.

[0057] [Simulation Method of Polymer Material (Third Embodiment)] Incidentally, it is known that when a polymer material is heated, cleavage (cutting) of molecular chains is promoted and the material is liable to deteriorate. In order to evaluate the state of deterioration of the polymer material due to such heating, the reaction step S6 may further include a step of heating the applied molecular chain model 2. In this embodiment, for the same configuration as in the previous embodiments, the same reference numerals may be given and the description may be omitted.

[0058] In the reaction step S6 of this embodiment, among the calculation conditions set in step S4, heating of the applied molecular chain model 2 is calculated by setting a large value for the temperature. The timing for increasing the value of the temperature can be appropriately set according to the purpose of the analysis. For example, the temperature may be set large at the start of the chemical reaction calculation, or the temperature may be set large during the chemical reaction calculation.

[0059] In the reaction step S6 of this embodiment, compared with the previous examples in which the molecular chain model 2 was not heated, the cleavage of the molecular chain model 2 shown in FIG. 7(a) is promoted, and further, the binding (chemical reaction) of the oxygen particle model 5o to the cleaved molecular chain model 2 shown in FIG. 7(b) can be promoted. Thereby, in the reaction step S6 of this embodiment, it becomes possible to evaluate the state of deterioration of the polymer material due to heating.

[0060] As described above, the particularly preferred embodiments of the present disclosure have been described in detail. However, the present disclosure is not limited to the illustrated embodiments and can be implemented in various forms.

Example

[0061] Based on the processing procedure shown in FIG. 2, the chemical reaction between the molecular chain and the molecule was calculated (Example 1 and Example 2). In Example 1 and Example 2, distortion was applied to the molecular chain model, and a reaction step of calculating the chemical reaction between the applied molecular chain model and the molecular model was carried out based on the density functional tight binding method. In Example 2, unlike Example 1, the applied molecular chain model was heated.

[0062] Based on the processing procedure shown in FIG. 7, the chemical reaction between the molecular chain and the molecule was calculated (Example 3). In Example 3, unlike Example 1 and Example 2, prior to the reaction step, a step of optimizing the structure of the applied molecular chain model based on the molecular orbital method was carried out.

[0063] For comparison, among the processing procedures shown in FIG. 2, by omitting the application step, the chemical reaction between the unapplied molecular chain model and the molecular model was calculated (Comparative Example). The common specifications are as follows. Molecular chain: Butadiene rubber Molecule: Oxygen Threshold value of distortion of polymer material model: 0.3 Temperatures of Example 1, Example 3 and Comparative Example: 400 K Temperature of Example 2: 450 K

[0064] As a result of the tests, in Examples 1 to 3, as shown in FIGS. 7(a) to (b), the state in which the molecular chain model was cleaved (cracked) and the state in which the chemical reaction (oxidation) was promoted by the cleavage of the molecular chain model were calculated. On the other hand, in the comparative example, although the chemical reaction of the molecular chain model was calculated, the state in which the molecular chain model was cleaved and the state in which the chemical reaction was promoted by the cleavage could not be calculated. Thus, Examples 1 to 3, unlike the comparative example, were able to simultaneously consider the influence of the mechanical force acting on the molecular chain and the chemical reaction between molecules.

[0065] In Example 2, as the molecular chain model was heated, the state in which the cleavage of the molecular chain model was promoted and the state in which the chemical reaction was promoted were calculated. Therefore, in Example 2, the state of deterioration of the polymer material due to heating could be evaluated.

[0066] In Example 3, prior to the reaction step, the structure of the applied molecular chain model was optimized based on the molecular orbital method, so that the chemical reaction calculation could be converged earlier than in Examples 1 and 2.

[0067] [Appendix] The present disclosure includes the following aspects.

[0068] [Disclosure 1] A method for simulating a polymer material, comprising: inputting into a computer a molecular chain model that models the molecular chain of the polymer material; inputting into the computer a molecular model that models a molecule for examining a reaction with the molecular chain, wherein the computer performs an application step of applying strain or stress to at least the molecular chain model; and performs a reaction step of calculating a chemical reaction between the applied molecular chain model and the molecular model based on the density functional tight binding method. A method for simulating a polymer material. [Disclosure 2] The printing step includes a step of stretching the molecular chain model in a predetermined direction, and is a method for simulating a polymer material according to Disclosure 1. [Disclosure 3] Before the reaction step, the method for simulating a polymer material according to Disclosure 1 or 2 includes a step of optimizing the structure of the applied molecular chain model based on the molecular orbital method. [Disclosure 4] The molecular model models a molecule that oxidizes the molecular chain. The reaction step is a method for simulating a polymer material according to any one of Disclosures 1 to 3, and calculates the oxidized state of the applied molecular chain model. [Disclosure 5] The reaction step further includes a step of heating the applied molecular chain model, and is a method for simulating a polymer material according to any one of Disclosures 1 to 4. [Disclosure 6] The method for simulating a polymer material according to any one of Disclosures 1 to 5 includes a step of evaluating the degradation state of the polymer material based on the molecular chain model after the reaction step.

Explanation of Reference Signs

[0069] S1 Step of inputting a molecular chain model S2 Step of inputting a molecular model S5 Printing step S6 Reaction step

Claims

1. A method for simulating a polymer material, comprising: inputting a molecular chain model obtained by modeling the molecular chains of the polymer material into a computer; inputting a molecular model obtained by modeling a molecule for examining the reaction with the molecular chain into the computer, wherein the computer performs an application step of applying strain or stress to at least the molecular chain model; and performs a reaction step of calculating a chemical reaction between the applied molecular chain model and the molecular model based on the density functional tight binding method. A method for simulating a polymer material.

2. The method for simulating a polymer material according to claim 1, wherein the application step includes a step of stretching the molecular chain model in a predetermined direction.

3. The method for simulating a polymer material according to claim 1 or 2, further including a step of optimizing the structure of the applied molecular chain model based on the molecular orbital method prior to the reaction step.

4. The molecular model is obtained by modeling a molecule that oxidizes the molecular chain, and the reaction step calculates a state in which the applied molecular chain model is oxidized. The method for simulating a polymer material according to any one of claims 1 to 3.

5. The method for simulating a polymer material according to any one of claims 1 to 4, wherein the reaction step further includes a step of heating the applied molecular chain model.

6. The method for simulating a polymer material according to any one of claims 1 to 5, further including a step of evaluating a degradation state of the polymer material based on the molecular chain model after the reaction step.

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