Simulation method of reversible addition-fragmentation chain transfer polymerization reaction, storage medium and computer program

Abstract

The invention provides a simulation method of a reversible addition-fragmentation chain transfer (RAFT) polymerization reaction, a storage medium and a computer program.The simulation method comprises the steps that modeling is carried out on the dynamic process of element reactions of all steps of the RAFT polymerization reaction, and based on the occurrence probability of the element reactions in the reaction process, the element reactions of all the steps of the RAFT polymerization reaction are obtained; the change of the molecular number and structure of reactants and products (including intermediate products and final products) along with the reaction time can be obtained, the structure information of more polymer chains can be obtained, and the method can be used for researching the influence of different reactant feeding, reaction temperature and time on the structure and distribution of the RAFT polymerization product. Moreover, in the simulation method of the reversible addition-fragmentation chain transfer polymerization reaction provided by the embodiment of the invention, each monomer unit of a long-chain molecule in the current primitive reaction is represented by an identifier; the identifiers of all the monomer units of the long-chain molecule are stored in the composite linked list structure in the form of nodes according to the molecular structure of the long-chain molecule, that is, the composite linked list structure only stores the identifiers and does not need to store each monomer unit of the long-chain molecule; the efficiency of the simulation method of the reversible addition-fragmentation chain transfer polymerization reaction is greatly improved.

Description

Technical Field

[0001] This invention relates to the field of computational simulation, and more particularly to a simulation method, storage medium, and computer program for a reversible addition-fragmentation chain transfer polymerization reaction. Background Technology

[0002] Reversible addition-fragmentation chain transfer (RAFT) polymerization is a common method for synthesizing polymers with narrow molecular weight distribution, precise molecular weight, controllable topology, and well-defined end-group functions. Its wide range of monomers, mild reaction conditions, and absence of metal catalysts have attracted widespread attention from researchers. RAFT polymerization introduces a compound called a RAFT reagent (RAFT chain transfer agent) into the traditional free radical polymerization system, achieving "active" chain growth through reversible addition / fragmentation reactions with free radicals.

[0003] The complex structures of RAFT polymerization products necessitate detailed kinetic simulations to optimize their structure. Conventional simulations based on numerical solutions of reaction kinetic differential equations only provide average information about the product structure, failing to offer a comprehensive understanding of the polymerization products. Kinetic Monte Carlo (KMC) simulations, specifically designed for simulating the long-term evolution of systems, are computer simulation methods based on random sampling. They obtain numerical results through multiple random samplings. By employing KMC simulations, the structural changes of each individual polymer chain can be obtained based on the probability of each elementary reaction during the reaction process, thus providing more structural information about the polymer chains. However, due to the diverse types of long-chain molecular structures in RAFT polymerization, while providing more structural information about the polymer chains, KMC simulations also suffer from limitations in efficient execution.

[0004] Therefore, providing an efficient Monte Carlo simulation method for the kinetics of reversible addition-fragmentation chain transfer polymerization is currently one of the research priorities. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a simulation method, storage medium and computer program for reversible addition-fragmentation chain transfer polymerization reaction, which can efficiently execute the simulation method for reversible addition-fragmentation chain transfer polymerization reaction.

[0006] To address the aforementioned problems, this invention provides a simulation method for reversible addition-fragmentation chain transfer polymerization. The reaction mechanism of the reversible addition-fragmentation chain transfer polymerization includes N elementary reactions, where N is a natural number greater than 0. The method includes a unit step of executing one of the elementary reactions. The unit step includes: calculating the tendency function of each elementary reaction based on the reaction parameters of each elementary reaction; calculating the time step of the current elementary reaction based on the sum of the tendency functions of all elementary reactions; randomly selecting one of the N elementary reactions as the current elementary reaction based on the tendency function of each elementary reaction; updating the species and the number of molecules of each species in the reaction system, updating the reaction time, and updating the complex chain list structure involved in the long-chain molecules in the current elementary reaction based on the current elementary reaction. The reaction time is the sum of the reaction time of the previous elementary reaction and the time step of the current elementary reaction. Each monomer unit of the long-chain molecule in the current elementary reaction is represented by an identifier, and the identifiers of all monomer units of the long-chain molecule are based on the molecular structure of the long-chain molecule. The nodes are stored in the composite linked list structure; the unit steps are executed cyclically until the reaction time reaches the set total reaction time or no elementary reaction can be executed; wherein, the composite linked list structure is constructed using the following method: a first molecular type linked list is constructed, the first molecular type linked list includes a first doubly linked list and a first data structure, the nodes of the first doubly linked list are composed of UniChain molecular chain structures, the UniChain molecular chain structure members include: a pointer variable mid1 pointing to the first data structure, a pointer variable prev1 pointing to the previous UniChain molecular chain structure, and a pointer variable next1 pointing to the next UniChain molecular chain structure; the first data structure includes a first singly linked list, the nodes of the first singly linked list are composed of UniUnit molecular structures, the UniUnit molecular structure members include a character variable data11 representing the identifier of the monomer unit and a pointer variable next11 pointing to another UniUnit molecular structure;Construct a second molecular type linked list, which includes a second doubly linked list and a second data structure. The nodes of the second doubly linked list are composed of BiChain molecular chain structures. Members of the BiChain molecular chain structure include: a pointer variable mid2 pointing to the second data structure, a pointer variable prev2 pointing to the previous BiChain molecular chain structure, and a pointer variable next2 pointing to the next BiChain molecular chain structure. The second data structure includes BiUnit molecular structures and a second singly linked list. Members of the BiUnit molecular structure include a character variable data21 representing the identifier of a monomer unit, a pointer variable next21 pointing to the head node of one of the second singly linked lists, and a pointer variable next2 pointing to the head node of another of the second singly linked lists. 22. The nodes of the second singly linked list are composed of UniUnit molecular structures. The UniUnit molecular structure members include a character variable `data11` representing the identifier of a monomer unit and a pointer variable `next11` pointing to another UniUnit molecular structure. A third molecular type linked list is constructed, comprising a third doubly linked list and a third data structure. The nodes of the third doubly linked list are composed of TriChain molecular chain structures. The TriChain molecular chain structure members include: a pointer variable `mid3` pointing to the third data structure, a pointer variable `prev3` pointing to the previous TriChain molecular chain structure, and a pointer variable `next3` pointing to the next TriChain molecular chain structure. The third data structure includes a TriUnit molecular structure and a third singly linked list. The TriUnit molecular structure members include: a character variable `data31` representing the identifier of a monomer unit, a pointer variable `next31` pointing to the head node of one of the third singly linked lists, a pointer variable `next32` pointing to the head node of another of the third singly linked lists, and a pointer variable `next` pointing to the head node of yet another of the third singly linked lists. 33. The nodes of the third singly linked list are composed of UniUnit molecular structures. The UniUnit molecular structure members include a character variable `data11` representing the identifier of a single unit and a pointer variable `next11` pointing to another UniUnit molecular structure.

[0007] Some embodiments of the present invention also provide a computer-readable storage medium storing a control program, which, when executed by a processor, implements the simulation method for the reversible addition-fragmentation chain transfer polymerization reaction as described above.

[0008] Some embodiments of the present invention also provide a computer program product, the computer program product comprising a computer program, which, when executed by a processor, implements the simulation method for the reversible addition-fragmentation chain transfer polymerization reaction as described above.

[0009] The simulation method for reversible addition-fragmentation chain transfer polymerization provided in this invention model the kinetics of each elementary reaction in the RAFT polymerization reaction. Based on the probability of each elementary reaction occurring during the reaction, the method can obtain the changes in the number and structure of reactants and products (including intermediates and final products) with reaction time, and can obtain more structural information of the polymer chains. This method can be used to study the effects of different reactant feeds, reaction temperatures and times on the structure and distribution of RAFT polymerization products.

[0010] Furthermore, in the simulation method for reversible addition-fragmentation chain transfer polymerization provided in this embodiment of the invention, each monomer unit of the long-chain molecule in the current elementary reaction is represented by an identifier. The identifiers of all monomer units of the long-chain molecule are stored in the composite linked list structure in the form of nodes according to the molecular structure of the long-chain molecule. That is, the composite linked list structure only stores identifiers and does not need to store each monomer unit of the long-chain molecule, which greatly improves the efficiency of the simulation method for reversible addition-fragmentation chain transfer polymerization of the present invention. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0012] Figure 1 This is a schematic diagram of the unit steps of a simulation method for a reversible addition-fragmentation chain transfer polymerization reaction provided in an embodiment of the present invention;

[0013] Figure 2 This is a schematic diagram of a first molecular type linked list provided in an embodiment of the present invention;

[0014] Figure 3 This is a schematic diagram of a second molecular type linked list provided in an embodiment of the present invention;

[0015] Figure 4 This is a schematic diagram of a third molecular type linked list provided in an embodiment of the present invention;

[0016] Figure 5 This is a schematic diagram of the molecular structure of a RAFT chain transfer agent;

[0017] Figure 6This is a schematic flowchart of a simulation method for a reversible addition-fragmentation chain transfer polymerization reaction provided in an embodiment of the present invention;

[0018] Figure 7 This is a monomer conversion rate versus time curve provided in an embodiment of the present invention;

[0019] Figure 8 This is a chain length distribution curve of a long-chain molecule provided in an embodiment of the present invention. Detailed Implementation

[0020] The following detailed description, in conjunction with the accompanying drawings, outlines the specific implementation methods, storage media, and computer programs for the reversible addition-fragmentation chain transfer polymerization reaction provided by this invention.

[0021] The reaction mechanism of reversible addition-fragmentation chain transfer (RAFT) polymerization involves N elementary reactions, where N is a natural number greater than 0.

[0022] Specifically, in one embodiment, the reaction mechanism of the reversible addition-fragmentation chain transfer (RAFT) polymerization reaction includes the following 13 elementary reactions:

[0023] Classical free radical polymerization reaction steps:

[0024] (1) Initiator decomposition: I2 → 2f×I*

[0025] (2) Chain triggering: I*+A→A1*

[0026] (3) Chain growth: A i *+A→A i+1 *

[0027] (4) Chain termination: A i *+A j *→A i+j

[0028] RAFT pre-equilibrium reaction steps:

[0029] (5) Chain addition: A i *+RT→RT*A i

[0030] (6) Chain breakage: RT*A i →TA i +R*

[0031] (7) Chain initiation: R*+A→A1*

[0032] (8) Chain addition: TA i +R*→RT*A i

[0033] (9) Chain breakage: RT*Ai →A i *+RT

[0034] RAFT master equilibrium reaction steps:

[0035] (10) Chain addition: A i *+TA j →A i T*A j

[0036] (11) Chain breakage: A i T*A j →A i *+TA j

[0037] RAFT steps to terminate the reaction:

[0038] (12) Chain termination: A i *+RT*A j →RT(A i A j

[0039] (13) Chain termination: A i *+A j T*A k →A i T(A j A k

[0040] Where I2 is the initiator, f is the initiation efficiency, I* is the primary free radical of the initiator, and A is the monomer. i * represents a chain growth free radical, RT represents a RAFT chain transfer agent, and RT*A represents a chain growth free radical. i R* is a primary intermediate free radical, R* is a RAFT chain transfer agent leaving group free radical, TA i For the dormant chain, A i+j For dead polymer chains, RT(A) i A j and A i T(A j A k All of them are molecular chains containing the "T" group in the molecular structure of RAFT chain transfer agents.

[0041] The method includes a unit step of performing one of the elementary reactions, the unit step comprising:

[0042] Calculate the tendency function of each elementary reaction step based on the reaction parameters of each elementary reaction step.

[0043] The time step of the current elementary reaction is calculated based on the sum of the tendency functions of all elementary reactions.

[0044] Based on the tendency function of each elementary reaction step, one of the N elementary reactions is randomly selected as the current elementary reaction.

[0045] Based on the current elementary reaction, update the species and the number of molecules of each species in the reaction system, update the reaction time, and update the complex linked list structure involved in the long-chain molecules in the current elementary reaction. The reaction time is the sum of the reaction time of the previous elementary reaction and the time step of the current elementary reaction. Each monomer unit of the long-chain molecule in the current elementary reaction is represented by an identifier. The identifiers of all monomer units of the long-chain molecule are stored in the complex linked list structure in the form of nodes according to the molecular structure of the long-chain molecule.

[0046] The unit steps are executed repeatedly until the reaction time reaches the set total reaction time or no elementary reaction can be executed.

[0047] The simulation method for reversible addition-fragmentation chain transfer polymerization (RAFT) provided in this invention is a kinetic Monte Carlo simulation method. This method models the kinetics of each elementary reaction step in the RAFT polymerization reaction. Based on the probability of each elementary reaction occurring during the reaction, it can obtain the changes in the number and structure of reactants and products (including intermediates and final products) with reaction time, providing more structural information about the polymer chains. This can be used to study the effects of different reactant feeds, reaction temperatures, and times on the structure and distribution of RAFT polymerization products. Furthermore, each monomer unit of the long-chain molecule in the current elementary reaction is represented by an identifier. The identifiers of all monomer units of the long-chain molecule are stored in the composite linked list structure in the form of nodes according to the molecular structure of the long-chain molecule. That is, the composite linked list structure only stores identifiers and does not need to store the individual monomer units of the long-chain molecule, greatly improving the efficiency of the simulation method for reversible addition-fragmentation chain transfer polymerization of this invention.

[0048] Specifically, Figure 1 This is a schematic diagram of the unit steps of a simulation method for a reversible addition-fragmentation chain transfer polymerization reaction provided in an embodiment of the present invention, in conjunction with... Figure 1 The above-mentioned elementary reactions (1) to (13) provide a detailed description of the simulation method for the reversible addition-fragmentation chain transfer polymerization reaction provided by the present invention.

[0049] An embodiment of the present invention provides a simulation method for reversible addition-fragmentation chain transfer polymerization, comprising unit steps, each unit step performing an elementary reaction, wherein the unit steps include:

[0050] Step S10: Calculate the propensity function of each elementary reaction based on the reaction parameters of each elementary reaction. The propensity function is determined by the reaction rate constant and the state of the system, and is related to the probability of reactant molecule collisions and the probability of a reaction occurring during a collision. In this step, the propensity functions of all elementary reactions involved in the reversible addition-fragmentation chain transfer polymerization are calculated; for example, the propensity functions of elementary reactions (1) to (13) are calculated.

[0051] In some embodiments, the tendency function of each elementary reaction step is calculated based on the rate constant of each elementary reaction step, the number of reactant molecules, and the current volume of the reaction system.

[0052] In some embodiments, the method for calculating the tendency function includes:

[0053] For unimolecular elementary reactions, such as elementary reaction (1), elementary reaction (6), elementary reaction (9), and elementary reaction (11), the tendency function is calculated using the following formula (1):

[0054] a j =k j n i Formula (1)

[0055] Among them, a j Let k be the tendency function of the j-th elementary reaction. j Let n be the rate constant of the j-th elementary reaction, j≤N, n i denoted as the number of molecules of the i-th reactant. The j-th elementary reaction is the elementary reaction carried out in the current unit step, and the i-th reactant is the reactant participating in the current elementary reaction.

[0056] For bimolecular elementary reactions where the reactants are different types of molecules, such as elementary reaction (2), elementary reaction (5), elementary reaction (7), elementary reaction (8), elementary reaction (10), elementary reaction (12), and elementary reaction (13), the tendency function is calculated using the following formula (2):

[0057]

[0058] Among them, a j Let k be the tendency function of the j-th elementary reaction. j Let N be the rate constant of the j-th elementary reaction, j≤N, N A Let n be Avogadro's constant, V be the current volume of the reaction system, and n be the volume of the reaction system. i1 and n i2These represent the number of molecules of reactant i1 and reactant i2, respectively. The j-th elementary reaction is the elementary reaction carried out in the current unit step, and reactants i1 and i2 are the reactants participating in the current elementary reaction.

[0059] For bimolecular elementary reactions where the reactants are the same type of molecules, such as elementary reaction (3) and elementary reaction (4), the tendency function is calculated using the following formula (3):

[0060]

[0061] Among them, a j Let k be the tendency function of the j-th elementary reaction. j Let N be the rate constant of the j-th elementary reaction, j≤N, N A Let n be Avogadro's constant, V be the current volume of the reaction system, and n be the volume of the reaction system. i denoted as the number of molecules of the i-th reactant. The j-th elementary reaction is the elementary reaction carried out in the current unit step, and the i-th reactant is the reactant participating in the current elementary reaction.

[0062] In step S10, when calculating the tendency function of an elementary reaction, if the number of reactant molecules in an elementary reaction is zero, the tendency function of that elementary reaction is zero.

[0063] Step S11: Calculate the time step of the current elementary reaction based on the sum of the tendency functions of all elementary reactions. This step yields the time required to complete the elementary reaction performed in this unit step.

[0064] In some embodiments, the time step of the current elementary reaction is calculated using the following formula (4):

[0065]

[0066] Where τ is the time step of the current elementary reaction, a tot The sum of the tendency functions of all elementary reactions is given by r1, which is a random number between 0 and 1. The sum of the tendency functions of all elementary reactions can be obtained by summing the tendency functions obtained in step S10.

[0067] Step S12: Randomly select one of the N elementary reactions as the current elementary reaction based on the tendency function of each elementary reaction. The tendency function of the elementary reaction reflects the probability of the elementary reaction occurring. In this step, the elementary reaction to be executed in the current unit step is randomly selected based on the tendency function of the elementary reaction.

[0068] In some embodiments, the numbering of the selected elementary reactions satisfies the following formula (5):

[0069]

[0070] Where μ is the number of the selected elementary reaction, μ≤N, a j Let r2 be the tendency function of the j-th elementary reaction, j≤N, and r2 be a random number between 0 and 1. tot It is the sum of the tendency functions of all elementary reactions. For example, the reaction mechanism of reversible addition-fragmentation chain transfer (RAFT) polymerization includes the following 13 elementary reactions, then μ can take any natural number from 1 to 13.

[0071] In step S12, one of the elementary reactions that satisfy the above formula (5) is selected as the elementary reaction to be performed in the current unit step.

[0072] Step S13: Based on the current elementary reaction, update the species in the reaction system and the number of molecules of each species, update the reaction time, and update the complex linked list structure involved in the long-chain molecules in the current elementary reaction. The reaction time is the sum of the reaction time of the previous elementary reaction and the time step of the current elementary reaction. Each monomer unit of the long-chain molecule in the current elementary reaction is represented by an identifier. The identifiers of all monomer units of the long-chain molecule are stored in the complex linked list structure in the form of nodes according to the molecular structure of the long-chain molecule.

[0073] After the current elementary reaction is completed, the types and number of molecules of substances in the reaction system will change. In this step, the types of substances in the reaction system and the number of molecules of each species are updated.

[0074] The reaction time is the sum of the reaction time of the previous elementary reaction and the time step of the current elementary reaction. That is, in step S13, the reaction time is the sum of the reaction time obtained in the previous unit step and the time step obtained in this unit step. In other words, the reaction time accumulates as the simulation method progresses.

[0075] The composite linked list structure is associated with long-chain molecules. If long-chain molecules are present in the reactants and products of the current elementary reaction, the composite linked list structure is updated. Each monomer unit of the long-chain molecule in the current elementary reaction is represented by an identifier. The identifiers of all monomer units of the long-chain molecule are stored in the composite linked list structure as nodes according to the molecular structure of the long-chain molecule. That is, the composite linked list structure only stores identifiers and does not need to store the individual monomer units of the long-chain molecule, which greatly improves the efficiency of the simulation method for reversible addition-fragmentation chain transfer polymerization of the present invention.

[0076] Each monomer unit of the long-chain molecule in the current elementary reaction is represented by a character type in the composite linked list structure. The composite linked list structure can be output to an external text file. The identifiers of all monomer units of the long-chain molecule are stored in the composite linked list structure in the form of nodes according to the molecular structure of the long-chain molecule. The text file can then be used to analyze the detailed structural characteristics of the polymerization product, and further used to study the effects of different reactant feeds, reaction temperatures and times on the structure and distribution of RAFT polymerization products.

[0077] In some embodiments, different types of monomer units in the composite linked list structure are represented by different identifiers. By analyzing the order of the identifiers, the order of monomer units in the formed long-chain molecule can be analyzed, so that the structure of the long-chain molecule can be further clarified in subsequent analysis.

[0078] Some embodiments of the present invention also provide a method for constructing a composite linked list structure. In one embodiment, the method includes constructing a first molecular type linked list, constructing a second molecular type linked list, and constructing a third molecular type linked list.

[0079] Please see Figure 2 , Figure 2 This is a schematic diagram of a first molecular type linked list. The first molecular type linked list includes a first doubly linked list 20 and a first data structure. The nodes of the first doubly linked list 20 are composed of UniChain molecular chain structures 201. Members of the UniChain molecular chain structure 201 include: a pointer variable mid1 pointing to the first data structure, a pointer variable prev1 pointing to the previous UniChain molecular chain structure 201, and a pointer variable next1 pointing to the next UniChain molecular chain structure 201. The first data structure includes a first singly linked list 211. The nodes of the first singly linked list 211 are composed of UniUnit molecular structures 2110. Members of the UniUnit molecular structure include a character variable data11 representing the identifier of a monomer unit and a pointer variable next11 pointing to another UniUnit molecular structure.

[0080] The first type of molecular linked list refers to a linked list corresponding to a long-chain molecule with one chain. Figure 2 In the schematic diagram shown, a node of the first singly linked list 211 is used to represent a single unit, and the character variable data11 of the node is assigned the identifier of the single unit.

[0081] In some embodiments, the chain-growing free radical A involved in the elementary reaction i*Stored in the first molecule type linked list, the pointer variable mid1 of the first doubly linked list 20 points to the head node of the first singly linked list 211, and the character variable data11 of each node of the first singly linked list 211 is assigned the value of the chain-growing free radical A. i The identifier of the monomer unit in *. For example, if the monomer unit is identified by the letter "A", then the character variable data11 of the UniUnit molecular structure of the corresponding node in the first unidirectional linked list 211 is assigned the value "A". If the initiator unit is identified by the letter "I", then the character variable data11 of the UniUnit molecular structure of the corresponding node in the first unidirectional linked list 211 is assigned the value "I". If the RAFT chain transfer agent leaving group unit is identified by the letter "R", then the character variable data11 of the UniUnit molecular structure of the corresponding node in the first unidirectional linked list 211 is assigned the value "R". If the chain growth free radical A i If other single-units exist, the corresponding node of the first singly linked list 211 is assigned the identifier of that single-unit.

[0082] Please see Figure 3 , Figure 3 This is a schematic diagram of a second molecular type linked list. The second molecular type linked list is constructed, comprising a second doubly linked list 30 and a second data structure 31. The nodes of the second doubly linked list 30 are composed of BiChain molecular chain structures 301. Members of the BiChain molecular chain structure 301 include: a pointer variable mid2 pointing to the second data structure 31, a pointer variable prev2 pointing to the previous BiChain molecular chain structure, and a pointer variable next2 pointing to the next BiChain molecular chain structure. The second data structure 31 includes a BiUnit molecular structure 310 and a second singly linked list 311. Members of the BiUnit molecular structure 310 include a character variable data21 representing the identifier of a monomer unit, a pointer variable next21 pointing to the head node of one of the second singly linked lists 311, and a pointer variable next22 pointing to the head node of another of the second singly linked lists 311. The nodes of the second singly linked list 311 are composed of UniUnit molecular structures 3110. The members of UniUnit molecular structure 3110 include a character variable data11 representing the identifier of a single unit and a pointer variable next11 pointing to another UniUnit molecular structure.

[0083] The second type of molecular chain list refers to the chain list corresponding to long-chain molecules with two chains. Figure 3 In the schematic diagram shown, a node of the second singly linked list 311 is used to represent a single unit, and the character variable data11 of the node is assigned the identifier of the single unit.

[0084] In some embodiments, the dead polymer chain A involved in the elementary reaction i+j Stored in the second type of molecular linked list, the pointer variable mid2 of the second doubly linked list 30 points to the BiUnit molecular structure 310. The character variable in the BiUnit molecular structure 310 is assigned the value "X" to mark the connection site when the free radical coupling of the two chains terminates. The character variable data11 of each node in the second unidirectional linked list 311 is assigned the value of dead polymer chain A. i+j The identifier of the monomer unit in the second unidirectional linked list 311. For example, if the monomer unit is identified by the letter "A", then the character variable data11 of the UniUnit molecular structure 3110 at the corresponding node of the second unidirectional linked list 311 is assigned the value "A". If the initiator unit is identified by the letter "I", then the character variable data11 of the UniUnit molecular structure 3110 at the corresponding node of the second unidirectional linked list 311 is assigned the value "I". If the dead polymer chain A i+j If other single-unit units exist, the corresponding node of the second singly linked list 311 is assigned the identifier of that single-unit unit.

[0085] Please see Figure 4 , Figure 4This is a schematic diagram of a third molecular type linked list. The third molecular type linked list is constructed by including a third doubly linked list 40 and a third data structure 41. The nodes of the third doubly linked list 40 are composed of TriChain molecular chain structures 401. Members of the TriChain molecular chain structure 401 include: a pointer variable mid3 pointing to the third data structure 41, a pointer variable prev3 pointing to the previous TriChain molecular chain structure, and a pointer variable next3 pointing to the next TriChain molecular chain structure. The third data structure 41 includes a TriUnit molecular structure 410 and a third singly linked list 411. Members of the TriUnit molecular structure 410 include: a character variable data31 representing the identifier of a monomer unit, a pointer variable next31 pointing to the head node of one of the third singly linked lists 411, a pointer variable next32 pointing to the head node of another of the third singly linked lists 411, and a pointer variable next33 pointing to the head node of yet another of the third singly linked lists 411. The nodes of the third singly linked list 411 are composed of UniUnit molecular structures 4110. The members of the UniUnit molecular structure 4110 include a character variable data11 representing the identifier of a single unit and a pointer variable next11 pointing to another UniUnit molecular structure.

[0086] The third type of molecular chain list refers to the chain list corresponding to long-chain molecules with three chains. Figure 4 In the schematic diagram shown, a node of the third singly linked list 411 is used to represent a single unit, and the character variable data11 of the node is assigned the identifier of the single unit.

[0087] In some embodiments, the molecular chain containing the "T" group in the RAFT chain transfer agent molecular structure involved in the elementary reaction is stored in the third molecular type list. The "T" group in the RAFT chain transfer agent molecular structure is a transfer group; for example, in one embodiment, the RAFT chain transfer agent molecular structure is as follows: Figure 5 As shown, it is a schematic diagram of the molecular structure of a RAFT chain transfer agent, where R is a free radical leaving group and the "T" group is the group circled by the dashed box in the figure.

[0088] Molecular chains containing "T" groups in the molecular structure of RAFT chain transfer agents, such as the primary intermediate free radical RT*A. i intermediate free radical A i T*A j TA hibernation chain i Dead polymer chain RT(A) i A j and A i T(A jA k The pointer variable mid3 of the third doubly linked list 40 points to the TriUnit molecular structure 410. The character variable in the TriUnit molecular structure 410 is assigned the value "T" to represent the RAFT chain transfer agent molecular structure. The character variable data11 of each node in the third unidirectional linked list 411 is assigned the identifier of the monomer unit in the molecular chain containing the "T" group in the RAFT chain transfer agent molecular structure. For example, if the monomer unit is identified by the letter "A", then the character variable data11 of the UniUnit molecular structure 4110 of the corresponding node in the third unidirectional linked list 411 is assigned the value "A"; if the initiator unit is identified by the letter "I", then the character variable data11 of the UniUnit molecular structure 4110 of the corresponding node in the third unidirectional linked list 411 is assigned the value "I"; if the RAFT chain transfer agent leaving group unit is identified by the letter "R", then the character variable data11 of the UniUnit molecular structure 4110 of the corresponding node in the third unidirectional linked list 411 is assigned the value "R". If the molecular chain containing the "T" group in the RAFT chain transfer agent molecular structure also contains other monomer units, then the corresponding node of the third unidirectional linked list 411 is assigned the identifier of that monomer unit.

[0089] If the elementary reaction involves long-chain molecules with three or more chains, a linked list corresponding to the number of chains can be constructed. The construction method can refer to the method for constructing a linked list of third molecular types.

[0090] The above is one method for constructing a composite linked list structure. In other embodiments, other methods can also be used to construct the composite linked list structure, as long as the nodes of the composite linked list structure can be used to store the identifiers of individual units.

[0091] In some embodiments, step S13 further includes: if the reactants of the current elementary reaction have long-chain molecules, then selecting long-chain molecules participating in the reaction from the composite linked list structure corresponding to the molecular type of the long-chain molecule using uniformly distributed random integers. Specifically, if the reactants of the current elementary reaction are long-chain molecules with one chain, then selecting long-chain molecules participating in the elementary reaction from the first molecular type linked list using uniformly distributed random integers.

[0092] In some embodiments, for long-chain molecular reactants with reactive ends, long-chain molecular reactants with the same terminal monomer unit are considered as the same reactant, and are accumulated when calculating the number of reactant molecules.

[0093] The above is a unit step. The simulation method for reversible addition-fragmentation chain transfer polymerization reaction includes cyclically executing the unit step (steps S10 to S13) until the reaction time reaches the set total reaction time or no elementary reaction can be executed, at which point the reaction terminates.

[0094] In some embodiments, before cyclically executing the unit steps, the method further includes setting reaction parameters, which include: the volume of the reaction system, the reaction kinetic parameters of the elementary reaction, the concentration of reactants, the initial number of molecules of at least one reactant, and the total reaction time. That is, in the initial stage of the simulation method for reversible addition-fragmentation chain transfer polymerization, reaction parameters are set to provide data for subsequent simulation processes.

[0095] In some embodiments, the volume of the reaction system can be obtained based on the pre-set density and concentration of the reactants. For example, referring to elementary reactions (1) to (13), in the initial stage of the reaction, the reactants are I2, A, and RT. The density and concentration of one of the reactants (e.g., reactant A) can be set, and the volume of the reaction system can be obtained based on the density and concentration of the reactant. The volume of the reaction system remains unchanged throughout the simulation.

[0096] If the ratio of reactant molecule numbers to reactant concentrations is equal, then in some embodiments of this application, the initial molecule numbers of other reactants can be obtained based on the initial molecule number of one reactant and the concentrations of other reactants. For example, referring to elementary reactions (1) to (13), in the initial stage of the reaction, the reactants are I2, A, and RT. The initial molecule number of one reactant (e.g., reactant A) and the concentration of another reactant (e.g., reactant I2) can be set, and then the initial molecule number of reactant I2 can be obtained based on the initial molecule number of reactant A and the concentration of reactant I2, or the initial molecule number of reactant RT can be obtained based on the initial molecule number of reactant A and the concentration of reactant RT.

[0097] The number of reactant molecules involved in the elementary reaction during the simulation can be increased or decreased based on the initial number of molecules and the number of molecules participating in the reaction during the simulation steps.

[0098] In one embodiment, the reaction kinetic parameters of the elementary reaction include the initiator efficiency f and the reaction rate constant k of each elementary reaction step.

[0099] The present invention also provides a computer-readable storage medium storing a control program, which, when executed by a processor, implements a simulation method for the reversible addition-fragmentation chain transfer polymerization reaction as described above.

[0100] The present invention also provides a computer program product comprising a computer program that, when executed by a processor, implements the simulation method for the reversible addition-fragmentation chain transfer polymerization reaction as described above.

[0101] The following is combined Figure 6 And elementary reactions (1) to (13), further describing the simulation method for reversible addition-fragmentation chain transfer polymerization provided in an embodiment of the present invention, Figure 6 This is a schematic flowchart of a simulation method for a reversible addition-fragmentation chain transfer polymerization reaction provided in an embodiment of the present invention.

[0102] Please see Figure 6 At the beginning of the simulation, reaction parameters are input, including: reaction system volume V, initiator efficiency f, and reaction rate constants k1 to k2. 13 The initial number of molecules of each reactant n(I2), n(A), n(RT), and the total reaction time t. tot The initial reaction time t is zero.

[0103] Execution unit steps:

[0104] Calculate the tendency function a for each elementary reaction step based on the reaction parameters of each elementary reaction step. j And the sum of the tendency functions of all elementary reactions, a tot In this step, the tendency functions of the elementary reactions are calculated based on unimolecular reactions, bimolecular reactions with the same type of reactants, and bimolecular reactions with different types of reactants. The sum of the tendency functions of all elementary reactions is obtained by summing all the tendency functions.

[0105] The time step τ of the current elementary reaction is calculated based on the sum of the tendency functions of all elementary reactions. Specifically, the time step τ of the current elementary reaction is calculated according to formula (4) above.

[0106] Based on the tendency function of each elementary reaction step, one of the N elementary reactions is randomly selected as the current elementary reaction (i.e., a random number r2 between 0 and 1 is generated, and the reaction channel is randomly selected). The number of the selected elementary reaction satisfies formula (5).

[0107] Based on the current elementary reaction, update the species in the reaction system and the number of molecules of each species, update the reaction time, and update the complex chain list structure involved in the long-chain molecules in the current elementary reaction. The species involved in the reaction system include: I2, I*, A, and A. i *、RT、RT*A i R*, RAFT, TA i A i+j RT(A) i Aj and A i T(A j A k The reaction time is the sum of the reaction time of the previous elementary reaction and the time step of the current elementary reaction, that is, the sum of the reaction time in the previous unit step and the time step of the current elementary reaction.

[0108] After this unit step is executed, determine whether the reaction time is greater than or equal to the total reaction time t. tot If yes, then the simulation process ends; otherwise, the unit step is executed again, that is, the tendency function 'a' of each elementary reaction is calculated based on the reaction parameters of each elementary reaction. j The steps are repeated multiple times until the reaction time is greater than or equal to the total reaction time.

[0109] In some embodiments, the end of the simulation process may not be controlled by the total reaction time, but by whether there are reactants in the reaction system that can react. For example, it may be determined whether there are still reactants that can react. If there are, the unit step is executed again; if not, the simulation process is terminated.

[0110] The following example uses the RAFT polymerization of methyl acrylate (MA) as an example, with azobisisobutyronitrile (AIBN) as the initiator and cumyl dithiobenzoate (CDB) as the chain transfer agent. The specific implementation steps of the simulation method for the reversible addition-fragmentation chain transfer polymerization reaction are as follows:

[0111] (1) Define the volume of the simulation system as 10. -18 The number of AIBN molecules is 6022, the number of CDB molecules is 30110, and the number of MA monomer molecules is 6202804. At this time, the concentration of AIBN is 0.02 mol / L, the concentration of CDB is 0.05 mol / L, and the concentration of MA is 10.3 mol / L.

[0112] (2) Define the kinetic parameters in the RAFT polymerization mechanism, where the initiator efficiency f is 0.64 and the initiator decomposition rate constant k1 is 1.5 × 10⁻⁶. -4 s -1 The rate constants k2, k3, and k7 for chain initiation and chain propagation reactions are all set to 3.18 × 10⁻⁶. 4 L / (mol·s), the chain termination reaction rate constant k4 is 3×10 8 The rate constant for the chain addition reaction is 3.06 × 10 L / (mol·s). 8 The rate constant for the chain scission reaction is k6, with a flow rate of L / (mol·s) and a s-value of 20.9 s. -1 The rate constant of chain addition reaction, k 10It is 9.36×10 6 L / (mol·s), chain scission reaction rate constant k 11 784s -1 The rate constant k for the coupling termination reaction between intermediate free radicals 12 and k 13 All are set to 4.5×10 7 L / (mol·s).

[0113] (3) Define the total reaction time as 1 hour.

[0114] (4) Start the simulation. (a) Calculate the tendency function of the elementary reaction based on the rate constant, reactant molecules, and current volume of the reaction system for each elementary reaction step. (b) Calculate the time step of the current Monte Carlo simulation unit step based on the overall tendency function. (c) Randomly select a reaction channel using the tendency function of each elementary reaction step as the probability distribution. (d) Update the number of reactant species and molecules based on the selected reaction channel, i.e., the reaction occurring in the current Monte Carlo simulation unit step, and simultaneously update the current reaction time. If the current elementary reaction contains long-chain molecules, update the complex chain list structure involved in the long-chain molecule.

[0115] (5) Repeat steps (a) to (d) until the reaction time reaches the set total reaction time of 1 hour.

[0116] (6) Export the text file recording the changes in reactant concentrations, and analyze the monomer conversion rate of long-chain molecules over time, such as... Figure 7 It is a curve showing the change in monomer conversion rate of long-chain molecules over time. Figure 7 Analysis shows that the monomer conversion rate of monomer A in the long-chain molecule is 32.8% after 1 hour of reaction.

[0117] (6) Export the text file recording the structural changes of long-chain molecules. Analysis can yield the chain length distribution curves of the long-chain molecules, such as... Figure 8 It is the chain length distribution curve of long-chain molecules, from Figure 8 Analysis shows that the weight-average molecular weight of the polymerized long-chain molecules after 1 hour of reaction is 6801, and the polydispersity index (PDI) is 1.12.

[0118] It should be noted that the terms "comprising" and "having," and their variations, used in this invention document are intended to cover non-exclusive inclusion. The terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence, unless explicitly indicated by the context; it should be understood that such use of data can be interchanged where appropriate. The term "one or more" depends at least in part on the context and can be used to describe features, structures, or characteristics in a singular sense, or in a plural sense to describe combinations of features, structures, or characteristics. The term "based on" can be understood as not necessarily intended to express an exclusive set of factors, but can instead, also at least in part on the context, allow for the presence of other factors that are not necessarily explicitly described. Furthermore, embodiments and features in embodiments of this invention can be combined with each other without conflict. In addition, descriptions of well-known components and technologies have been omitted in the above description to avoid unnecessarily obscuring the concepts of this invention. In the various embodiments described above, each embodiment focuses on its differences from other embodiments; similar / identical parts between embodiments can be referred to mutually.

[0119] The above description is only a preferred embodiment of the present invention. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for simulating reversible addition-fragmentation chain transfer polymerization, characterized in that, The reaction mechanism of the reversible addition-fragmentation chain transfer polymerization reaction includes N elementary reactions, where N is a natural number greater than 0. The method includes a unit step of performing one of the elementary reactions, the unit step including: Calculate the tendency function of each elementary reaction step based on the reaction parameters of each elementary reaction step; The time step of the current elementary reaction is calculated based on the sum of the tendency functions of all elementary reactions; Based on the tendency function of each elementary reaction, one of the N elementary reactions is randomly selected as the current elementary reaction; Based on the current elementary reaction, update the species and the number of molecules of each species in the reaction system, update the reaction time, and update the complex linked list structure involved in the long-chain molecules in the current elementary reaction. The reaction time is the sum of the reaction time of the previous elementary reaction and the time step of the current elementary reaction. Each monomer unit of the long-chain molecule in the current elementary reaction is represented by an identifier. The identifiers of all monomer units of the long-chain molecule are stored in the complex linked list structure in the form of nodes according to the molecular structure of the long-chain molecule. The unit steps are executed repeatedly until the reaction time reaches the set total reaction time or no elementary reaction can be executed. The composite linked list structure is constructed using the following method: Construct a first molecular type linked list, which includes a first doubly linked list and a first data structure. The nodes of the first doubly linked list are composed of UniChain molecular chain structures. The UniChain molecular chain structure members include: a pointer variable mid1 pointing to the first data structure, a pointer variable prev1 pointing to the previous UniChain molecular chain structure, and a pointer variable next1 pointing to the next UniChain molecular chain structure. The first data structure includes a first singly linked list, the nodes of which are composed of UniUnit molecular structures. The UniUnit molecular structure members include a character variable data11 representing the identifier of a monomer unit and a pointer variable next11 pointing to another UniUnit molecular structure. Construct a second molecular type linked list, which includes a second doubly linked list and a second data structure. The nodes of the second doubly linked list are composed of BiChain molecular chain structures. The members of the BiChain molecular chain structure include: a pointer variable mid2 pointing to the second data structure, a pointer variable prev2 pointing to the previous BiChain molecular chain structure, and a pointer variable next2 pointing to the next BiChain molecular chain structure. The second data structure includes a BiUnit molecular structure and a second singly linked list. The members of the BiUnit molecular structure include a character variable data21 representing the identifier of a monomer unit, a pointer variable next21 pointing to the head node of one of the second singly linked lists, and a pointer variable next22 pointing to the head node of another of the second singly linked lists. The nodes of the second singly linked list are composed of UniUnit molecular structures. The members of the UniUnit molecular structure include a character variable data11 representing the identifier of a monomer unit and a pointer variable next11 pointing to another UniUnit molecular structure. A third molecular type linked list is constructed, comprising a third doubly linked list and a third data structure. The nodes of the third doubly linked list are composed of TriChain molecular chain structures. Members of the TriChain molecular chain structure include: a pointer variable mid3 pointing to the third data structure, a pointer variable prev3 pointing to the previous TriChain molecular chain structure, and a pointer variable next3 pointing to the next TriChain molecular chain structure. The third data structure comprises TriUnit molecular structures and a third singly linked list. Members of the TriUnit molecular structure include: a character variable data31 representing the identifier of a monomer unit, a pointer variable next31 pointing to the head node of one of the third singly linked lists, a pointer variable next32 pointing to the head node of another of the third singly linked lists, and a pointer variable next33 pointing to the head node of yet another of the third singly linked lists. The nodes of the third singly linked list are composed of UniUnit molecular structures. Members of the UniUnit molecular structure include a character variable data11 representing the identifier of a monomer unit and a pointer variable next11 pointing to another UniUnit molecular structure.

2. The simulation method for reversible addition-fragmentation chain transfer polymerization according to claim 1, characterized in that, The step of calculating the tendency function of each elementary reaction step based on the reaction parameters of each elementary reaction step further includes: calculating the tendency function of each elementary reaction step based on the rate constant of each elementary reaction step, the number of reactant molecules, and the current volume of the reaction system, wherein the method for calculating the tendency function includes: For unimolecular elementary reactions, the tendency function is calculated using the following formula (1): a j =k j n i Formula (1) Among them, a j Let k be the tendency function of the j-th elementary reaction. j Let n be the rate constant of the j-th elementary reaction, j≤N, n i Let i be the number of molecules of the i-th reactant; For bimolecular elementary reactions where the reactants are different types of molecules, the tendency function is calculated using the following formula (2): Among them, a j Let k be the tendency function of the j-th elementary reaction. j Let N be the rate constant of the j-th elementary reaction, j≤N, N A Let n be Avogadro's constant, v be the current volume of the reaction system, and n be the volume of the system. i1 and n i2 These are the number of molecules of the i1th and i2th reactants, respectively; For bimolecular elementary reactions where the reactants are the same type of molecule, the tendency function is calculated using the following formula (3): Among them, a j Let k be the tendency function of the j-th elementary reaction. j Let N be the rate constant of the j-th elementary reaction, j≤N, N A Let n be Avogadro's constant, V be the current volume of the reaction system, and n be the volume of the reaction system. i denoted as the number of molecules of the i-th reactant.

3. The simulation method for reversible addition-fragmentation chain transfer polymerization according to claim 1, characterized in that, The step of calculating the time step of the current elementary reaction based on the sum of the tendency functions of all elementary reactions further includes: calculating the time step of the current elementary reaction using the following formula (4): Where τ is the time step of the current elementary reaction, a tot R1 is the sum of the tendency functions of all elementary reactions, and r1 is a random number between 0 and 1.

4. The simulation method for reversible addition-fragmentation chain transfer polymerization according to claim 1, characterized in that, The step of randomly selecting one of the N elementary reactions as the current elementary reaction based on the tendency function of each elementary reaction further includes: the numbering of the selected elementary reaction satisfies the following formula (5): Where μ is the number of the selected elementary reaction, μ≤N, a j Let r2 be the tendency function of the j-th elementary reaction, j≤N, and r2 be a random number between 0 and 1. tot It is the sum of the tendency functions of all elementary reactions.

5. The simulation method for reversible addition-fragmentation chain transfer polymerization according to claim 1, characterized in that, In the composite linked list structure, different types of individual units are represented by different identifiers.

6. The simulation method for reversible addition-fragmentation chain transfer polymerization according to claim 1, characterized in that, The long-chain molecule includes chain-growing free radicals, dead polymer chains, and molecular chains containing "T" groups in the RAFT chain transfer agent molecular structure. The chain-growing free radicals are stored in the first molecular type list, the dead polymer chains are stored in the second molecular type list, and the molecular chains containing "T" groups in the RAFT chain transfer agent molecular structure are stored in the third molecular type list.

7. The simulation method for reversible addition-fragmentation chain transfer polymerization according to claim 1, characterized in that, The steps of updating the species and the number of molecules of each species in the reaction system, updating the reaction time, and updating the complex linked list structure involved in the long-chain molecules in the current elementary reaction, based on the current elementary reaction, further include: if the reactants of the current elementary reaction have long-chain molecules, then the long-chain molecules participating in the reaction are selected by uniformly distributed random integers in the complex linked list structure corresponding to the molecular type of the long-chain molecules.

8. The simulation method for reversible addition-fragmentation chain transfer polymerization according to claim 1, characterized in that, For long-chain molecular reactants with reactive ends, long-chain molecular reactants with the same terminal monomer unit are considered as the same reactant.

9. The simulation method for reversible addition-fragmentation chain transfer polymerization according to claim 1, characterized in that, Before the unit steps are executed in a loop, the method further includes setting reaction parameters, which include: the volume of the reaction system, the reaction kinetic parameters of the elementary reaction, the concentration of the reactants, the initial number of molecules of at least one reactant, and the total reaction time.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a control program that, when executed by a processor, implements a simulation method for the reversible addition-fragmentation chain transfer polymerization reaction as described in any one of claims 1-9.

11. A computer program product, the computer program product comprising a computer program, characterized in that, When the computer program is executed by a processor, it implements a simulation method for the reversible addition-fragmentation chain transfer polymerization reaction as described in any one of claims 1-9.

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