A Digitally Controlled Flow–Batch Platform for Reproducible Radical Copolymerization with Reduced Composition Drift

Free-radical copolymerization is widely used industrially, but scale transfer can alter polymer properties through changes in mixing and heat transfer. We developed a digitally controlled flow–batch platform integrating a micromixer, heated tubular reactor, and batch reactors. The flow stage provided reproducible mixing and rapid thermal preconditioning at low conversion, whereas the batch stage completed polymerization at high conversion and enabled programmed monomer dosing. Heating the shared upstream stage suppressed early formation of a high-molecular-weight fraction. A feed-rate function whose time dependence reflects superposed, time-shifted initiator-decay contributions was empirically calibrated from residual-monomer data and implemented through 1 min Pump C set-point updates, reducing composition drift. Timed valve switching enabled sequential use of four batch reactors under the same local flow conditions, yielding 1.97 kg of dry copolymer in 8 h. By separating thermal preconditioning from composition control, the platform provides a reproducible small-lot production strategy within the tested operating window.