A Combined Computational and Experimental Study of Copolymerization Propagation Kinetics for 1‐Ethylcyclopentyl methacrylate and Methyl methacrylate

Abstract

The crosspropagation of 1-ethylcyclopentyl methacrylate (ECPMA) and methyl methacrylate (MMA) has been studied using a combination of quantum chemistry calculations and experiment. Our computational work utilizes a trimer-to-tetramer reaction model, coupled with an ONIOM (B3LYP/6-31G(2df,p): B3LYP/6-31G(d)) method for geometry optimization and an M06-2X/6-311+G(2df,p) method plus SMD solvation model for single point energy calculations. The results show several trends: the identity of the ultimate unit of a trimer radical affects not only the preferred conformation of the region where the reaction takes place, but also the reactivity of the radical; the addition of an ECPMA monomer to the radicals is generally favored compared to an MMA monomer; the pen-penultimate unit of a trimer radical shows a nonnegligible entropic effect; the penultimate unit effect is implicit for the ECPMA-MMA copolymer system. Finally, terminal model reactivity ratios fi tted based on the explicit rate coeffi cients calculated from the quantum chemical results are compared with those from experimental measurements. The computations not only agree qualitatively with experimentally derived results in terms of the selectivity of ECPMA-MMA crosspropagation, but also give reasonable quantitative predictions of reactivity ratios.

Computational Package for Copolymerization Reactivity Ratio Estimation: Improved Access to the Error-in-Variables-Model

“…Hence, the cumulative and instantaneous mole fractions in the copolymer are about the same. This experimental fact (and subsequent analysis) is considered "best practice," and is used throughout the reactivity ratio estimation literature (see, for example, [10,[12][13][14]16,17]). …”

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].…”

Monomer Structure and Solvent Effects on Copolymer Composition in (Meth)acrylate Radical Copolymerization

“…The reactivity ratios that characterize x MA/ x MA copolymerizations are typically near unity meaning that both x MA react with equal addition probabilities. This is true for simple systems like MMA/DMA, but also for x MA bearing diverse functional groups in their ester side chains such as 2-(2-bromopropionyloxy) propyl methacrylate, AAEMA, or 1-ethylcyclopentyl methacrylate . Furthermore, a variety of x MA/ n -alkyl acrylate ( x A) pairs consistently produce methacrylate-rich copolymers. ,,, For such x MA/ x MA and x MA/ x A copolymerization systems, it is found that the effect of solvent choice on copolymer composition is small as long as the difference in monomer and solvent polarities is not large. ,− As summarized by Figure , the H-bonding capabilities of the HEMA/BMA and HEMA/BA systems cause copolymer composition to deviate from their respective expected behaviors.…”