Theoretical study of the free‐radical copolymerization of styrene with methyl methacrylate: Comparative study to the styrene–acrylonitrile monomer system

Abstract

Enthalpic and electronic terminal and penultimate unit effects in the free-radical copolymerization of styrene (S) with methyl methacrylate (M) were investigated by quantum mechanical calculations at 0 and 298 K. Total energies, zero-point energies scaled by a 0.96 factor, and thermal enthalpy corrections for all optimized structures were computed at the B3-LYP/6-31G(d) level of theory. Differences in enthalpies for elementary propagation reactions at 0 and 298 K did not exceed 0.6 kcal/mol. Enthalpic effects of the replacement of S by M in the penultimate position of the growing radicals in elementary copolymerization propagation reactions (enthalpic penultimate unit effects) were always positive, ranging from 1.2 to 3.3 kcal/mol at 298 K. The values suggested that the elementary propagation reactions involving more S units in the growing polymer chain ends should be slightly thermodynamically preferred. A comparison of these results with those for the S-acrylonitrile monomer system showed that the most crucial feature differentiating enthalpic effects for the two monomer systems is the replacement of M by acrylonitrile in the reaction pair CH 3 -S-M ⅐ ϩ M 3 CH 3 -S-M-M ⅐ and CH 3 -M-M ⅐ ϩ M 3 CH 3 -M-M-M ⅐ .

DFT Modeling of the Alternating Radical Copolymerization and Alder-Ene Reaction between Maleic Anhydride and Olefins

“…The reasons of the formation of alternate polymers by MA and olefins are still unclear in detail. The methods of quantum chemistry based on the density functional theory were successfully used for the analysis of different radical polymerization processes [50][51][52], including homo-and copolymerization of acrylates [53][54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71], acrylamides [70,72,73], and acrylonitrile [74]. However, as far as we know, DFT-based methods have not been extensively used for visualization and comprehensive analysis of the free radical alternating copolymerization of donor and cyclic acceptor monomers, except the publications of Matsumoto et al, devoted to the copolymerization of N-methylmaleimide (MMI) with olefins [75], and MA with 2,4-dimethylpenta-1,3-diene [76].…”

Solvent effects on free-radical copolymerization of styrene and 2-hydroxyethyl methacrylate: a DFT study

“…It is important to note that there have been several studies [41][42][43][44][45] including our recent work [46][47][48][49] on the theoretical modeling of free-radical polymerization and copolymerization kinetics by means of quantum-chemical approaches; however, the vast majority of these theoretical studies focus on the evaluation of kinetic parameters without incorporating solvent effects. Among few theoretical studies including solvent effects is the work by Thickett and Gilbert 50 where a simple Polarizable Continuum Model (PCM) 51,52 was used to model the AA propagation kinetics; though, the method used in this study turned out to be insufficient for a quantitative description of the reaction rate.…”

Atom transfer radical copolymerizationof acrylonitrile/n‐butyl acrylate: Microstructure determination by two‐dimensional nuclearmagnetic resonance spectroscopy

“…In many cases, the utility of these copolymers in a specific industrial application depends on the molecular weight and structural properties. In the past, the synthesis of acrylonitrile copolymers4–7 has been accomplished with conventional free‐radical procedures, which lack the ability to control the macromolecular structure and molecular weight.…”