Virtual Free-Radical Polymerization of Vinyl Monomers in View of Digital Twins

Abstract

The first case of virtual polymerization based on the concept of digital twins (DTs) is presented. The free-radical polymerization of vinyl monomers is considered to be a chain reaction consisting of a set of elementary ones. Those three types, related to the polymerization initiation and propagation as well as to the termination of polymer chain growth, are discussed. Special sets of DTs, whose total number approaches 60, distinguish each reaction type. The calculations are carried out using a semi-empirical version of the unrestricted Hartree–Fock approximation. The main energy and spin-density parameters of the ground state of the DTs are determined. The barrier profiles of two pairs of DTs are calculated, based on which two Evans–Polanyi–Semenov relations, attributed to elementary reactions of type (1) and (2), are constructed. These provide a quite reliable evaluation of the activation energy for the initiation and propagation of the free-radical polymerization of vinyl monomers in all the cases. The decisive role of spins in the formation of the elementary reaction transition states is established.

The Triumph of the Spin Chemistry of Fullerene C60 in the Light of Its Free Radical Copolymerization with Vinyl Monomers

“…In this paper, it will be shown that the spin theory not only perfectly senses and responds to the slightest changes occurring in RSs, but also makes it possible to predict the results of behaviors of such media that have not yet been studied. Our consideration is based on the Digital Twins (DTs) concept [70], which allows one to play a virtual game with numerous event participants [71], providing the detection of trends characteristic of these radical events.…”

“…Sci. 2024, 25, x FOR PEER REVIEW 3 of 23 merous event participants [71], providing the detection of trends characteristic of these radical events.…”

“…One more uniqueness of the C60 molecule concerns its donor and/or acceptor (DA) abilities, both of which are strong [5,76]. This feature greatly influences the intermolecular interaction that accompanies molecule polymerization [77], controlling the height of barriers on the standard energy graphs that are characteristic for any chemical reaction [71]. For the first time, this was manifested in the course of the C60 fullerene virtual di- Lilac balls of different size on the FR image mark the first five atoms from the top of the ACS Z → A list of the N DA values of the fullerenyl, from 0.55 to 0.29 e. These atoms form a set of targets for the next addition, being located at a one-, two-, three-, and four-bond distance from atom A.…”

“…One more uniqueness of the C 60 molecule concerns its donor and/or acceptor (DA) abilities, both of which are strong [5,76]. This feature greatly influences the intermolecular interaction that accompanies molecule polymerization [77], controlling the height of barriers on the standard energy graphs that are characteristic for any chemical reaction [71]. For the first time, this was manifested in the course of the C 60 fullerene virtual dimerization [76], thus including reaction kinetics in the area of responsibility of the spin theory of the molecule.…”

“…Over the thirty-year history of C 60 fullerene polymerization, the spin theory of molecules was used twice to explain the features of this process: firstly, in the case of a dry all-carbon homogeneous oligomerization of C 60 fullerene from a dimer to tetramers [76,77], and, secondly, in the case of wet FRP of vinyl monomers [88][89][90][91]. In the first case, a computational technique was used for the first time to determine not only the coupling energy E cpl of the final reaction product, but also the activation energy E ad of its decomposition.…”