Mini-Pilot Scale Production of Homopolymer and Block Copolymer by Anionic Polymerization

Abstract

In order to obtain a large amount of polymer samples with a well-controlled molecular weight and polydispersity index, a bench scale reactor system for anionic polymerization was built instead of the traditional break-seal method. Homopolymers were successfully prepared from non-polar monomers in amounts of 40 similar to 350 g with well-defined structures. The major process variables were found to be the type of initiator, monomer concentration. and the volume of the reaction mixture. When a higher monomer concentration or larger reaction mixture volume was used, the removal of reaction heat became critical. In the case of a polar monomer, close control of the anionic polymerization was required to obtain a lower PDI. In the preparation of a diene-acryl block copolymer, it was found that the thorough removal of any impurities from the second monomer was critical for suppressing the generation of a homopolymer.