Microreactor-Based Green Synthetic Platform for Flow Synthesis of Biodegradable Polymers

Green synthetic strategies to biodegradable polymers have been paid much attention in the background of global attention to sustainable development. Bio- and organocatalyses for ring-opening polymerizations of cyclic monomers offer metal-free biodegradable polymers under mild conditions. With the benefits of a huge surface-to-volume ratio and flow characteristic, a microreactor exhibits unique advantages that cannot be had in a traditional batch reactor. The combination of flow chemistry and bio/organocatalysis provides a green synthetic platform for fast, efficient, and scalable generation of biodegradable polyesters and polycarbonates. This review summarizes ring-opening polymerizations of lactones, lactides, and carbonates by continuous flow biocatalysis, organocatalysis, and biochemical catalysis. Accelerated apparent polymerization rates, improved control of molecular weights and polydispersities, higher end group fidelities, and novel degradable polymeric materials with tunable properties were achieved by using a microreactor-based green synthetic platform. The challenges and opportunities are proposed with the aim to advance the development of the green synthesis and application of sustainable polymers.