Quantum‐Chemical Modeling of Free‐Radical Polymerization

Abstract

This article reviews recent progress in the application of quantum chemistry to radical polymerization processes, with a principle focus on establishing the current ‘best‐practice’ methodology for obtaining chemically accurate calculations. The scope and limitations of computational chemistry for this field are also discussed, and some of its leading applications in the areas of ab initio kinetic modeling and computer‐aided reagent design are highlighted.magnified image

First Principles Prediction of the Copolymerization Process of 1,3-Butadiene and Vinyl Chloride

“…A similar expression can be obtained for r 2 . Although accurate ab initio predictions of rate constants are difficult, we expect the reactivity ratio, r, to be more accurate because Equation 3 depends on the difference in G + + ∆ values.…”

“…This is necessary because computational costs increase dramatically with increasing chain-length [12]. The literature suggests that a backbone of four atoms is the minimum for convergence to the true polymer limit [2]. For this reason, in this work we have used a four atom chain-length as the minimum surrogate polymer size.…”

“…An alternative approach that has gained much attention in the last decade is known as ab initio kinetic modeling [2]. Rather than taking a top-down approach, this method starts at the molecular level without relying on any experimental data.…”

On the Use of Quantum Chemistry for the Determination of Propagation, Copolymerization, and Secondary Reaction Kinetics in Free Radical Polymerization

“…Computational approaches were first applied to the kinetic characterization of propagation reactions of small radicals, and then progressively moved towards the investigation of larger molecules [71,72]. The development of cost-effective methods, such as those based on the DFT, in combination with the increasing power of the calculators has made possible of scale-up, which was required to investigate chain-length dependency of rate coefficients and lately the reactivity of MCRs.…”

“…From the computational point of view, the solvent effect can be modeled considering explicit solvent molecules and characterizing the specific interactions, or using continuum models [71]. The former approach is clearly more effective, while it is often coupled with a prohibitive computational cost.…”