CN108334734B - High-molecular copolymer degradation modeling and simulation method - Google Patents

High-molecular copolymer degradation modeling and simulation method Download PDF

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CN108334734B
CN108334734B CN201710785288.1A CN201710785288A CN108334734B CN 108334734 B CN108334734 B CN 108334734B CN 201710785288 A CN201710785288 A CN 201710785288A CN 108334734 B CN108334734 B CN 108334734B
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张桃红
周绍楠
金戈愉
马瑞
李存芳
张德政
孙义
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University of Science and Technology Beijing USTB
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Abstract

The invention provides a high-molecular copolymer degradation modeling and simulation method, which can realize the simulation of a degradation process from the shear fracture of a molecular chain under a microscopic level to the diffusion modeling under a macroscopic level. The method comprises the following steps: dispersing the high molecular copolymer into cells; randomly selecting molecular chains participating in shearing based on the cells obtained through dispersion; establishing a molecular chain shear fracture model of the high-molecular copolymer based on the components of the copolymer, wherein the model is used for determining the fracture position of the molecular chain participating in shearing in a probabilistic manner through roulette according to the preset fracture probability among ester bond units in the molecular chain; the molecular chains participating in shearing are subjected to fragmentation at the determined fragmentation positions; after the molecular chains participating in shearing are broken at the determined breaking positions, the oligomer diffuses outwards. The invention relates to the technical field of degradable high polymer materials.

Description

High-molecular copolymer degradation modeling and simulation method
Technical Field
The invention relates to the field of degradable high polymer materials, in particular to a high polymer copolymer degradation modeling and simulation method.
Background
In recent years, degradable high molecular copolymers have been widely used in life, for example, tissue engineering materials in medical fields, drug controlled release materials, artificial implants, drug controlled release systems, and the like. The high molecular copolymer belongs to high molecular compounds, and the high molecular compounds refer to: compounds with a relative molecular weight of more than ten thousand formed by covalent bonding of a plurality of atoms or groups of atoms.
The different copolymerization ratios of the copolymers can lead to different mechanical properties, biological properties and degradation properties, and different requirements of practical application on materials can be met by changing the copolymerization ratios of the copolymers. The success of the application of these different performance requirements depends to a large extent on whether the degradation process is controllable. The degradation process of the high molecular copolymer is complex, and the copolymerization ratio among different copolymers can change along with the time in the degradation process. The research on the degradation process of the high molecular polymer can be divided into a traditional experimental method and a new computer modeling method, and the computer modeling method just makes up for the defect of long period of the traditional experimental method. However, most of the current computer modeling methods are modeling studies on the degradation process of a high molecular monomer, and even if a copolymer is involved, two copolymerization parts are treated as a single monomer, and the modeling on the copolymer component in the degradation process and the breakage study on different copolymerization molecular chains are not involved.
Disclosure of Invention
The invention aims to solve the technical problem of providing a high-molecular copolymer degradation modeling and simulation method to solve the problem that a high-molecular copolymer degradation model in the prior art does not research the fracture of copolymer components and copolymer molecular chains.
In order to solve the above technical problems, an embodiment of the present invention provides a method for modeling and simulating degradation of a polymer copolymer, including:
dispersing the high molecular copolymer into cells;
randomly selecting molecular chains participating in shearing based on the cells obtained through dispersion;
establishing a molecular chain shear fracture model of the high-molecular copolymer based on the components of the copolymer, wherein the model is used for determining the fracture position of the molecular chain participating in shearing in a probabilistic manner through roulette according to the preset fracture probability among ester bond units in the molecular chain;
the molecular chains participating in shearing are subjected to fragmentation at the determined fragmentation positions;
after the molecular chains participating in shearing are broken at the determined breaking positions, the oligomer diffuses outwards.
Further, the randomly selecting molecular chains participating in the shearing based on the discretely obtained unit cells includes:
and based on the cells obtained through dispersion, randomly selecting molecular chains participating in shearing and a shearing and breaking reaction time interval through a Monte Carlo algorithm.
Further, the probabilistically determining the cleavage site of the molecular chain participating in the cleavage by roulette according to the preset cleavage probability between ester bond units in the molecular chain includes:
and randomly selecting the breaking positions of the molecular chains participating in the shearing in a probability manner by roulette according to preset breaking probabilities among ester bond units in the molecular chains.
Further, the randomly selecting the cleavage positions of the molecular chains participating in the cleavage by roulette in a probabilistic manner according to the preset cleavage probability between ester bond units in the molecular chains includes:
a random number R is generated, wherein,
Figure BDA0001397871420000021
qiindicates the cleavage site between ester bond units,
Figure BDA0001397871420000022
represents an ester bond unit in qiThe probability of cleavage, M representing the number of cleavable positions in the molecular chain;
judging whether the random number R satisfies
Figure BDA0001397871420000023
Wherein q is0、
Figure BDA0001397871420000024
At a predetermined value, j ∈ [1, M]；
If so, the cleavage position of the molecular chain participating in the shearing is qj。
Further, the cleavage of the molecular chain participating in the cleavage at the determined cleavage position and the recording of the new number of chains comprises:
the participationThe scissored molecular chains being in cleavage position qjStrand breaks were performed, yielding two new strands, and the position of each ester linkage unit of the two new strands was recorded.
Further, the diffusion of the oligomer is calculated using a macroscopic diffusion equation expressed as:
Figure BDA0001397871420000031
wherein, CeIs the ester bond concentration of the high molecular copolymer, ColIs oligomer concentration, k1For hydrolysis reaction rate constant, k, without catalysis2In order to have the catalytic action condition, the hydrolysis reaction rate constant, D is a diffusion coefficient, grad represents a gradient, and div represents a divergence.
Further, the diffusion coefficient D is expressed as:
D＝D0+(1.32-0.33)(D1-D0)
wherein D is0Diffusion coefficient of oligomer in polymer, D1The diffusion coefficient of the oligomer in the pores is the porosity.
Further, the porosity is expressed as:
Figure BDA0001397871420000032
among them, CellsliquidTotal number of liquid Cells at time t, CellssumIs the total number of copolymer cells.
Further, after the cleavage of the molecular chain participating in the cleavage at the determined cleavage position and the diffusion of the oligomer to the outside, the method further comprises:
counting and recording the physical attributes of the cells and the proportion of the copolymerization components, and updating the state of the cells, wherein the physical attributes comprise: number of chains, molecular weight, mass;
and feeding back the counted chain number to the corresponding unit cell so as to carry out the shearing and breaking reaction of the copolymer molecular chain in the next round.
Further, after traversing all the cells, counting the number of chains, and feeding back the counted number of chains to the corresponding cells for the next round of the shear cleavage reaction of the copolymer molecular chain, the method further comprises:
and (3) calculating the variable quantity of the high-molecular copolymer in the degradation process according to the recorded physical properties, and simultaneously predicting the influence of different copolymerization components of molecular chains in the unit cells on the copolymerization ratio.
The technical scheme of the invention has the following beneficial effects:
in the scheme, the high molecular copolymer is dispersed into cells; randomly selecting molecular chains participating in shearing based on the cells obtained through dispersion; establishing a molecular chain shear fracture model of the high-molecular copolymer based on the components of the copolymer, wherein the model is used for determining the fracture position of the molecular chain participating in shearing in a probabilistic manner through roulette according to the preset fracture probability among ester bond units in the molecular chain; the molecular chains participating in shearing are subjected to fragmentation at the determined fragmentation positions; after the molecular chain participating in shearing is fractured at the determined fracture position, the oligomer diffuses outwards, so that the simulation of the degradation process from the shearing fracture of the molecular chain under the micro scale to the diffusion modeling under the macro scale is realized.
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FIG. 1 is a schematic flow chart of a polymer degradation modeling and simulation method according to an embodiment of the present invention;
FIG. 2 is a schematic diagram of a roulette wheel provided in accordance with an embodiment of the present invention;
FIG. 3 is a schematic view of a molecular chain of a copolymer provided in an embodiment of the present invention;
FIG. 4 is a schematic diagram of a roulette wheel with a probability of breaking an ester linkage unit according to an embodiment of the present invention;
FIG. 5 is a schematic diagram illustrating chain scission of a high molecular weight copolymer according to an embodiment of the present invention;
FIG. 6(a) is a graph showing the change of the molecular weight of PLGA (53:47) with degradation time according to the present invention;
FIG. 6(b) is a graph showing the mass loss of PLGA (53:47) over time, provided by an example of the present invention;
FIG. 7(a) is a graph showing the change of the molecular weight of PLGA (75:25) with degradation time according to the present invention;
FIG. 7(b) is a graph showing the mass loss of PLGA (75:25) over time, provided by an example of the present invention;
FIG. 8 is a G% comparison of different fracture probabilities provided by embodiments of the present invention.
Detailed Description
In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.
The invention provides a high-molecular copolymer degradation modeling and simulation method aiming at the problem that the existing high-molecular copolymer degradation model does not research the fracture of copolymer components and copolymer molecular chains.
As shown in fig. 1, the method for modeling and simulating degradation of a high molecular copolymer provided in the embodiment of the present invention includes:
s101, dispersing the high-molecular copolymer into cells;
s102, randomly selecting molecular chains participating in shearing based on the cells obtained through dispersion;
s103, establishing a molecular chain shear fracture model of the high-molecular copolymer based on the components of the copolymer, wherein the model is used for determining the fracture position of the molecular chain participating in shearing in a probability manner through roulette according to the preset fracture probability among ester bond units in the molecular chain;
s104, the molecular chains participating in shearing are subjected to fragmentation at the determined fragmentation positions;
and S105, after the molecular chain participating in shearing is broken at the determined breaking position, the oligomer diffuses outwards.
The polymer copolymer degradation modeling and simulation method provided by the embodiment of the invention disperses polymer copolymers into cells; randomly selecting molecular chains participating in shearing based on the cells obtained through dispersion; establishing a molecular chain shear fracture model of the high-molecular copolymer based on the components of the copolymer, wherein the model is used for determining the fracture position of the molecular chain participating in shearing in a probabilistic manner through roulette according to the preset fracture probability among ester bond units in the molecular chain; the molecular chains participating in shearing are subjected to fragmentation at the determined fragmentation positions; after the molecular chain participating in shearing is fractured at the determined fracture position, the oligomer diffuses outwards, so that the simulation of the degradation process from the shearing fracture of the molecular chain under the micro scale to the diffusion modeling under the macro scale is realized.
In this embodiment, a roulette diagram is shown in FIG. 2, wherein q isxThe position is indicated by a position indication,
Figure BDA0001397871420000051
represents the position qxThe fragmentation probability of (a), x 1,2, a.
In a specific embodiment of the foregoing method for modeling and simulating degradation of a polymer copolymer, further, the randomly selecting a molecular chain participating in shearing based on the discretely obtained unit cells includes:
and based on the cells obtained through dispersion, randomly selecting molecular chains participating in shearing and a shearing and breaking reaction time interval through a Monte Carlo algorithm.
In this embodiment, in order to determine the cleavage position of the molecular chain participating in the cleavage, a molecular chain cleavage model of the high molecular copolymer needs to be established. Because ester bond units in the molecular chain have different hydrophilicities, the probability of ester bond breakage caused by the connection of the ester bond units is different, and a molecular chain shearing breakage model of the high-molecular copolymer can be established based on the components of the copolymer. Assume that the molecular chain of the copolymer is as shown in FIG. 3, wherein Δ and. smallcircle indicate two different copolymers, respectively.
In the present example, it is assumed that △ represents polylactic acid (PLA) and ○ represents polyglycolic acid (PGA), and PLA and PGA are taken as examples, and q is taken as an exampleiRepresenting the position of the cleavage between ester bond units, and storing records in an array, wherein, i is 1, 2.... multidot.M; m, s and n respectively represent the fracture probability of preset different chain joints (among ester bond units) (the probability is simplified in the example, the fracture probability among the ester bonds is only divided into three types,i.e., P (PLA-PLA): p (PLA-PGA): p (PGA-PGA) ═ m: s: n). When the chain is cut and broken, the broken position can be randomly selected by roulette in a probabilistic manner.
In this embodiment, the step of randomly selecting the cleavage site of the molecular chain participating in cleavage by roulette in a probabilistic manner may include:
as shown in fig. 4, from q1The positions are respectively represented by q in the Chain Chain _ c of FIG. 3 in the counterclockwise direction from the beginning1To qx+y-1The probability of fracture.
Fracture position qjThe selection idea is as follows:
a random number R is generated, wherein,
Figure BDA0001397871420000061
the value of i is 1,2, wherein M represents the number of positions which can be broken in a molecular chain, and M is an integer which is more than or equal to 1;
increasing the constant q0、
Figure BDA0001397871420000062
Wherein q is0＝0，
Figure BDA0001397871420000063
Judging whether the random number R satisfies the formula (1):
Figure BDA0001397871420000064
if the random number R satisfies formula (1), the cleavage site of the molecular chain participating in cleavage is qjWherein, j ∈ [1, M]。
In this example, the molecular chain participating in the cleavage is at the cleavage site qjStrand breaks were performed, yielding two new strands, and the position of each ester linkage unit of the two new strands was recorded.
In a specific embodiment of the foregoing method for modeling and simulating the degradation of a high molecular copolymer, further, the diffusion of the oligomer is calculated by using a macroscopic diffusion equation, where the macroscopic diffusion equation is expressed as:
Figure BDA0001397871420000065
wherein, CeIs the ester bond concentration of the high molecular copolymer, ColIs oligomer concentration, k1For hydrolysis reaction rate constant, k, without catalysis2In order to have the catalytic action condition, the hydrolysis reaction rate constant, D is a diffusion coefficient, grad represents a gradient, and div represents a divergence.
In a specific embodiment of the foregoing method for modeling and simulating degradation of a polymer copolymer, further, the diffusion coefficient D is represented as:
D＝D0+(1.32-0.33)(D1-D0)
wherein D is0Diffusion coefficient of oligomer in polymer, D1The diffusion coefficient of the oligomer in the pores is the porosity.
In a specific embodiment of the foregoing method for modeling and simulating degradation of a polymer copolymer, further, the porosity is expressed as:
Figure BDA0001397871420000071
among them, CellsliquidTotal number of liquid Cells at time t, CellssumIs the total number of copolymer cells.
In a specific embodiment of the foregoing method for modeling and simulating degradation of a high molecular copolymer, further, after the molecular chains participating in shearing are cleaved at the determined cleavage positions, and the oligomer diffuses outward, the method further includes:
counting and recording the physical attributes of the cells and the proportion of the copolymerization components, and updating the state of the cells, wherein the physical attributes comprise: number of chains, molecular weight, mass;
and feeding back the counted chain number to the corresponding unit cell so as to carry out the shearing and breaking reaction of the copolymer molecular chain in the next round.
In a specific embodiment of the foregoing method for modeling and simulating degradation of a high molecular copolymer, further, after traversing all the cells, counting the number of chains, and feeding back the counted number of chains to the corresponding cells for the next round of shear cleavage reaction of the molecular chain of the copolymer, the method further includes:
and (3) calculating the variable quantity of the high-molecular copolymer in the degradation process according to the recorded physical properties, and simultaneously predicting the influence of different copolymerization components of molecular chains in the unit cells on the copolymerization ratio.
In summary, in this embodiment, a high molecular copolymer is discretized in a cellular manner, based on the cells obtained by discretization, molecular chains participating in shearing in a microscopic manner are randomly selected on different cells through a monte carlo algorithm, a shear fracture model of the molecular chains of the high molecular copolymer established based on the components of the copolymer is a fracture position of the molecular chains participating in shearing is randomly selected in a probabilistic manner through roulette, then diffusion of oligomers is calculated by using a macroscopic diffusion equation coupling, physical properties such as the number of chains, the molecular weight, the mass and the like of each cell are counted and recorded, and the variation of the high molecular copolymer in a degradation process is calculated according to the recorded physical properties; meanwhile, the influence of different copolymerization components of the molecular chain in the cellular on the copolymerization proportion is predicted, the simulation of the degradation process of the high-molecular copolymer from the shear fracture of the molecular chain under the microscopic condition to the macroscopic diffusion modeling is disclosed, and a data basis is provided for the optimized design of precise medical clinical equipment of the high-molecular copolymer. The invention is suitable for various application fields of degradable high molecular devices. In order to better understand the method for modeling and simulating the degradation of the polymer copolymer provided in this embodiment, the method for modeling and simulating the degradation of the polymer copolymer provided in this embodiment is described in detail by taking polylactic-co-glycolic acid (PLGA) as an example:
in this example, the polymer degradation was calculated based on two sets of experimental data of PLGA (53:47) and PLGA (75:25) with different copolymerization ratios; the parameters of the calculation model are set as: beta is 1000, beta represents the size of the dispersed equal cell of the high molecular copolymer, the fracture probability between ester bond units is set as m: s: n is 11:12:13, and other parameters are shown in table 1, wherein Mn represents the molecular weight.
TABLE 1 parameters of calculation models for different copolymerization ratios
Case Mn(g mol-1) D0(m2day-1) D1(m2day-1) k1 k2
PLGA(53:47) 1.4×104 4×10-10 1000×D0 12.9×10-3 0.001
PLGA(75:25) 1.3×104 1.2×10-10 1000×D0 10.3×10-3 0.005
The method comprises the following specific steps:
(1) as shown in FIG. 5, the high molecular copolymer PLGA was dispersed into β×β equal parts of cells (mesoscopic size cells), the cells were initialized, and the two-dimensional array Cell [ 2 ]][]Storage, cell (a, b) is written as: cell [ a ]][b]. At t1The molecular chain at the time point was: chain _ c (c is 0,1, 2.. said., H), contains X PLA ester linkage units and Y PGA ester linkage units, H represents the number of molecular chains in the unit cell, the middle part Chain corresponds to the position of the unit cell, and the one-dimensional array Temp [ C ], [ C ] is]And (4) storing.
(2) Setting the Cell state Cell [ a ] [ b ] _ state, and dividing the Cell [ a ] [ b ] _ state into three types:
Figure BDA0001397871420000081
neighbor cells may employ the von Neumann 4 neighbor model.
(3) As shown in FIG. 5, the chain number C is counted across all cellsI(I ═ 0,1, 2.., L), specifically: the number of chains containing different repeating units (C) is countedIThe chain representing the repeating unit I having CIStrip), using one-dimensional array ChainNumber [ 2 ]]And (5) storing.
(4) As shown in fig. 5, the molecular chain u participating in the shear (selecting the cleaved chain) and the shear cleavage reaction time interval Δ t are randomly determined according to the monte carlo algorithm; wherein the Monte Carlo algorithm comprises:
αv＝πvxAxB
Figure BDA0001397871420000082
Figure BDA0001397871420000083
wherein, pivDenotes the reaction constant, x, of the v-th shear cleavage reactionA、xBIndicating the number of reactant molecules participating in the v-th shear cleavage reaction, αvDenotes the reaction probability of shear fracture reaction, r1、r2Indicative of birth△ t is the time interval of two shearing and breaking reactions, u is the u th shearing and breaking reaction or the molecular chain participating in shearing at the next moment, and N is the number of shearing and breaking reactions.
(5) At t1At time + Δ t, the cleavage site q of the molecular chain involved in cleavage, determined according to formula (1)jAnd (3) performing chain breakage (ester bond breakage) to generate two new chains, updating the current cellular, specifically: the position of each ester linkage unit of the two new strands is recorded. (6) Recording the product of the step (5) and mesoscopic cells, counting physical attributes of the cells and updating the state of the cells, wherein the physical attributes comprise: number of chains, molecular weight, mass.
(7) Update time t1＝t1+Δt1When t is1<Δt2Time (Δ t)2: step of time), go back to step (3), otherwise, execute step (8).
(8) The diffusion of the oligomers was calculated using the macroscopic diffusion equation, where the copolymerization ratio would be varied by the number of diffused various ester bond units.
(9) Outputting a calculation result, counting and recording physical attributes of the cells and the proportion of the copolymerization components, and updating the state of the cells, wherein the physical attributes comprise: number of chains, molecular weight, mass;
(10) update time t2＝t2+Δt2Returning to the step (3) to carry out the next round of shear cleavage reaction of the copolymer molecular chain until t2And if the value is larger than the preset value, stopping iteration.
In this example, the comparison between the calculated values of PLGA (53:47) and PLGA (75:25) and the experimental data is shown in fig. 6(a), 6(b), and fig. 7(a) and 7(b), respectively, and the comparison between the calculated values of 6(a), 6(b), and fig. 7(a) and 7(b) and the experimental data verifies the correctness of the method for modeling and simulating the degradation of the polymer copolymer.
To investigate the influence of different probabilities on the degradation process, another set of fragmentation probability parameters m: s: n of 10:5:1 between ester linkage units was set, and the results of the ratio of PGA in copolymerization were calculated and compared with those in the previous case, and a comparison graph is shown in fig. 8. From FIG. 8, it can be found that the cleavage probability of the ester bond unit causes the change in the copolymerization ratio (G%) with time. It is known from the knowledge of polymer degradation that the ester linkage units of PGA are more hydrophilic than those of PLA, i.e. the proportion of PGA should be less and less, and the calculated value with the probability of m: s: n: 11:12:13 in fig. 8 is consistent with the actual value, and the calculated value with the probability of inter-ester linkage unit breakage of m: s: n: 10:5:1 is inconsistent with the actual value, which indicates that the method for modeling and simulating polymer copolymer degradation described in this embodiment is accurate in calculating different copolymerization ratios in the degradation of the copolymer. The influence of the fracture probability among ester bond units on the degradation process can be obtained by the method for modeling and simulating the degradation of the high molecular copolymer.
In this example, the influence of the fracture of the molecular chain of the copolymer on the degradation of the copolymer was studied based on the established shear fracture model of the molecular chain of the high molecular copolymer. The method comprises the following specific steps: by dispersing the high molecular copolymer device into mesoscopic sized cells; determining when a certain molecular chain is broken at any moment through a Monte Carlo algorithm; different breaking probabilities are set among ester bond units in the molecular chain, and the position of the ester bond unit is determined to be broken according to the probability; and counting the number of chains, the molecular weight, the state of the cells and the like of the cells, coupling and calculating the oligomer and a macroscopic diffusion equation, feeding back the new number of chains to the cells, carrying out the next round of shear fracture reaction of the molecular chain of the copolymer, and iterating in a multi-scale coupling manner to calculate the degradation process of the copolymer.
It is noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions.
While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.

Claims (8)

1. A method for modeling and simulating degradation of a high molecular copolymer is characterized by comprising the following steps:
dispersing the high molecular copolymer into cells;
randomly selecting molecular chains participating in shearing based on the cells obtained through dispersion;
establishing a molecular chain shear fracture model of the high-molecular copolymer based on the components of the copolymer, wherein the model is used for determining the fracture position of the molecular chain participating in shearing in a probabilistic manner through roulette according to the preset fracture probability among ester bond units in the molecular chain;
the molecular chains participating in shearing are subjected to fragmentation at the determined fragmentation positions;
after the molecular chains participating in shearing are broken at the determined breaking positions, the oligomer diffuses outwards;
the determining the cleavage positions of the molecular chains participating in the cleavage in a probabilistic manner by roulette based on the preset cleavage probability between ester bond units in the molecular chains includes:
and randomly selecting the breaking positions of the molecular chains participating in the shearing in a probability manner by roulette according to preset breaking probabilities among ester bond units in the molecular chains.
2. The method for modeling and simulating polymer copolymer degradation according to claim 1, wherein the randomly selecting molecular chains participating in shearing based on the discretely obtained unit cells comprises:
and based on the cells obtained through dispersion, randomly selecting molecular chains participating in shearing and a shearing and breaking reaction time interval through a Monte Carlo algorithm.
3. The method for modeling and simulating degradation of a polymer copolymer according to claim 1, wherein the randomly selecting the cleavage site of the molecular chain participating in the cleavage by roulette in a probabilistic manner according to the preset cleavage probability between ester bond units in the molecular chain comprises:
a random number R is generated, wherein,
Figure FDA0002605394270000011
i＝1,2,......,M，qiindicates the cleavage site between ester bond units,
Figure FDA0002605394270000012
represents an ester bond unit in qiThe probability of cleavage, M representing the number of cleavable positions in the molecular chain;
judging whether the random number R satisfies
Figure FDA0002605394270000013
Wherein q is0、
Figure FDA0002605394270000014
At a predetermined value, j ∈ [1, M]；
If so, the cleavage position of the molecular chain participating in the shearing is qj。
4. The method for modeling and simulating polymer copolymer degradation according to claim 3, wherein the cleaving the molecular chains participating in the shearing at the determined cleavage sites and recording the new number of chains comprises:
the molecular chain participating in shearing is at a cleavage position qjStrand breaks were performed, yielding two new strands, and the position of each ester linkage unit of the two new strands was recorded.
5. The method for modeling and simulating the degradation of a high molecular copolymer according to claim 1, wherein the diffusion of the oligomer is calculated using a macroscopic diffusion equation expressed as:
Figure FDA0002605394270000021
wherein, CeIs the ester bond concentration of the high molecular copolymer, ColIs oligomer concentration, k1For hydrolysis reaction rate constant, k, without catalysis2In order to have the catalytic action condition, the hydrolysis reaction rate constant, D is a diffusion coefficient, grad represents a gradient, and div represents a divergence.
6. The method for modeling and simulating the degradation of a high molecular copolymer according to claim 5, wherein the diffusion coefficient D is expressed as:
D＝D0+(1.32-0.33)(D1-D0)
wherein D is0Diffusion coefficient of oligomer in polymer, D1The diffusion coefficient of the oligomer in the pores is the porosity.
7. The method for modeling and simulating the degradation of a polymer copolymer according to claim 6, wherein the porosity is expressed as:
Figure FDA0002605394270000022
among them, CellsliquidTotal number of liquid Cells at time t, CellssumIs the total number of copolymer cells.
8. The method for modeling and simulating degradation of polymer copolymer according to claim 1, wherein after the molecular chains participating in shearing are cleaved at the determined cleavage sites and then the oligomer is diffused outward, the method further comprises:
counting and recording the physical attributes of the cells and the proportion of the copolymerization components, and updating the state of the cells, wherein the physical attributes comprise: number of chains, molecular weight, mass;
and feeding back the counted chain number to the corresponding unit cell so as to carry out the shearing and breaking reaction of the copolymer molecular chain in the next round.
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