In Silico Screening To Achieve Fast Lab-Scale Nitroxide-Mediated Polymerization of n-Butyl Acrylate with Maximal Control over Macromolecular Properties

Abstract

Nitroxide-mediated polymerization (NMP) allows one to synthesize well-defined polymers with narrow molar mass distribution (MMD) and latent functionality. For acrylates, however, side reactions, such as backbiting and β-scission and increases in viscosity, can complicate the molecular control, affecting the MMD dispersity, the double bound content, and the degree of livingness. On top of this, acrylate polymerizations are highly exothermic and thus dedicated temperature control is recommended, even under general lab-scale NMP conditions. In the present work, we account for both side reactions, diffusional limitations and nonisothermicity, so that a detailed model-based design for NMP of n-butyl acrylate can be performed in view of a better evaluation of its commercial potential. The relevance of temperature control and semibatch feeding strategies is particularly explored, benefiting from (i) a successful benchmark to NMP lab-scale batch literature data and (ii) a previous successful benchmark under various lab-scale free radical polymerization (FRP) conditions. It is showcased that specific set points of NMP characteristics, e.g., polymerization time, number average molar mass, and unsaturation level, can be achieved for a high monomer conversion by realizing less conventional thus nonlinear number average molar mass profiles, which is highly relevant for the polymer synthesis and reaction engineering community. The current work, which puts forward a dedicated research strategy from FRP to NMP to minimize error on kinetic parameter determination steps, opens the pathway to maximize the potential of reversible deactivation radical polymerization techniques for their more elegant implementation and appreciation in the society.