Tailoring Polymer Molecular Weight Distribution and Multimodality in RAFT Polymerization Using Tube Reactor with Recycle

Abstract Solution reversible addition fragmentation chain transfer (RAFT) polymerization of butyl acrylate in 50 wt% toluene, initiated with 2,2′‐azobisisobutyronitrile and mediated with 3‐benzyltrithiocarbonyl propionic acid, is carried out in a tube reactor of 1.65 mm inner diameter. The tube reactor is operated in three modes: batch tube reactor (inlet and outlet closed, recycle open), continuous tube reactor (inlet and outlet open, recycle closed), and loop tube reactor (inlet, outlet, and recycle all open). The effects of inlet and outlet flow rates, residence time, and recycle ratio on the polymerization rate and polymer molecular weight distribution (MWD) are systematically investigated. The dynamic and steady state kinetics of the three modes of operation are analyzed and compared. Polymer samples having multimodal MWD are generated using the loop reactor. It is found that the MWD and multimodality can be readily controlled by residence time (τ) and recycle ratio.