SimultaneousRegulation of Molecular Weight Distributionand Composition through RDRP in a Continuous-Flow Reactor: A KineticModeling

Regulating the molecular weight distribution (MWD) and copolymer composition is of great significance for controlling the properties of polymer materials. Combining reversible deactivation radical polymerization (RDRP) with continuous-flow synthesis techniques offers new opportunities to tailor complex MWDs. In the present work, we propose a flow-control strategy to simultaneously engineer the MWD and copolymer composition in atom transfer radical polymerization under continuous-flow conditions. A unique aspect of this approach is the intentionally designed flow rate profile, which can range from staged to quasi-continuous variations of the initiator injection flow rate. The relationship between flow rate profiles and the resulting MWD of the collected products was modeled by using Gaussian distribution mathematical equations and Monte Carlo simulations. The results show that this modeling method can not only predict the MWD from a given flow rate profile but also determine a flow rate scenario capable of producing any complex target MWD. Furthermore, we proposed a three-pump flow polymerization system capable of producing copolymers with tailored distributions and selective incorporation of comonomer units into specific product fractions. These conceptual demonstrations provide a theoretical framework for a new mode of MWD and composition regulation achieved simply by adjusting the injection flow profile of a given instrument configuration. This approach holds considerable potential for producing polymers with the desired MWDs and tailored chemical composition distributions.