Continuous free-radical polymerization with long-chain branching and scission in a tanks-in-series model

Abstract

Free-radical polymerization that involves the polymer transfer reactions, leading to both long-chain branching and scission, as in the cases of high-pressure ethylene polymerization, is considered for a tanks-in-series model. In a tanks-in-series model, the residence time distribution (RTD) becomes narrower to approach that for a plug flow reactor (PFR), as the number of tanks, N increases. The molecular weight distribution approaches rather quickly to that for a PFR, as the N-value increases. On the other hand, the branching density and the radius of gyration of highly branched polymers may show clear differences from that for a PFR, even when N-value is as large as 20. The present theoretical approach would provide great insight into the continuous production processes having complex RTDs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.