Continuous emulsion copolymerization processes at mild conditions in a 3D-printed tubular bended reactor

A polylactic acid tubular bended reactor, printed by fused deposition modeling with a short and narrow residence time distribution, air-cooled, and with dead volumes below 5 vol% was integrated into a modular reaction system enabling product changes in the running system. Continuous, redox-initiated emulsion copolymerizations of styrene - butyl acrylate and of vinyl acetate - neodecanoic acid vinyl ester were successfully performed with 20 and 40 wt% monomer in the feed. Copolymerizations had an ambient starting temperature with a mean residence time of 5 and 15 min, conversions were between 81 and 99%. The resulting emulsions were stable with Zeta potential values up to –132.0 mV and no product adhesion to the reactor wall was found. A stable steady state of the reaction plant was also obvious from thermal imaging, showing an invariant temperature profile along the 3D-printed reactor. The high versatility of the reactor system was shown by a grade transition between the copolymer systems with 20 wt% monomer content.