Synthesis of block copolymers using RAFT miniemulsion polymerization in a train of CSTRs

Continuous reversible addition fragmentation transfer (RAFT) miniemulsion block copolymerization of styrene and n-butyl acrylate (BA) in a train of continuous stirred tank reactors (CSTRs) is described. It is shown that a train of CSTRs can effectively be used to produce unique (multi)block copolymers. Comparison of gel permeation chromatography (GPC) refractive index (RI) traces and GPC UV traces revealed that the polymer formed has a very high percentage of living chains. The process variables such as flow rate, temperature, and injection point of the second monomer can easily be changed to obtain different block copolymers. The average composition and length of the individual blocks have been determined using H-1 NMR, GPC, and mass balances. The advantages and disadvantages of the continuous process for the production of block copolymers are discussed.