Modeling of “Living” Free-Radical Polymerization with RAFT Chemistry

A mathematical model is developed by combining living RAFT polymerization chemistry with a tank reactor model to analyze process development and design issues. Experimental data from MMA solution polymerization in a batch reactor are compared with the model to estimate the reversible reaction rate constants in the presence of the RAFT agent. Examples of a batch reactor, a single continuous stirred tank, a series of continuous stirred tank reactors, and a semibatch reactor are presented. Simulations show that a series of continuous stirred tanks might be appropriate for controlling polymer chain architecture as well as for achieving large-scale production of polymer products of interest. Semibatch reactors have the flexibility to prepare well-controlled polymers using RAFT chemistry. Selection of an initiator with an appropriate half-life and of the initiator concentration is important for good polymer properties and negligible initiator in the final product.