Scale-Up synthesis of thermoresponsive polymer particles from poly(N;N-dimethylacrylamide-co-N-isopropylacrylamide)-b-polystyrene via RAFT emulsion polymerization

Abstract

In this work, the reversible addition-fragmentation chain transfer (RAFT) emulsion polymerization of poly(N,N-dimethylacrylamide-co-N-isopropylacrylamide)-b-polystyrene is developed with the aim of scale-up of the polymer synthesis. Influences on the stability of the emulsion, reaction kinetics, and product quality are examined, compared between small-scale and bench-scale syntheses, and discussed in detail. The block copolymer lattices are studied via temperature-dependent dynamic light scattering measurements in order to investigate the effects of the scale-up on the thermosensitive behavior of the block copolymer and on emulsion stability. Conversion determination and polymer characterization are attained through 1H nuclear magnetic resonance (NMR) spectroscopy and gel permeation chromatography, respectively. The emulsion polymerization is successfully scaled up after several changes in the reaction composition and shows promising results regarding desired properties of the polymer.