A novel microfluidic enzyme-organocatalysis combination strategy for ring-opening copolymerizations of lactone, lactide and cyclic carbonate

Abstract

A novel microreactor-based enzyme-organocatalysis combination strategy was developed for ring-opening copolymerizations of varied types of cyclic monomers. Commercial Novozyme 435 (N435) and 1,5,7-triazabicyclo [4.4.0] dec-5-ene (TBD) were chosen as the model enzyme and organocatalyst for evaluating the polymerizations of ε-caprolactone (CL), δ-valerolactone (VL), l-lactide (LLA) and trimethylene carbonate (TMC) in the batch and microreactor respectively. Due to the catalytic selectivity, enzymatic polymerization cannot yield block copolymers containing PLA segment and organocatalysis showed poor activity toward CL polymerization. To address these challenges, enzyme and organocatalysis were combined based on microflow technology. In the assembled tandem microreactor system, series of well-defined triblock copolymers, such as PCL-b-PTMC-b-PVL, PCL-b-PTMC-b-PLLA and PTMC-b-PCL-b-PLLA, were efficiently prepared in the flow mode. The convenience of handling the copolymerization conditions and processes, reduced overall reaction time, well-controlled molecular weights and distributions were achieved by employing this microfluidic enzyme-organocatalysis combination strategy.