Organocatalyzed continuous flow ring-opening polymerizations to homo- and block-polylactones

- Organocatalyzed continuous flow polymerization was developed to metal-free polylactones.
- Precise regulations of Mn and ÐM were achieved by adjusting the flow rates.
- Apparent polymerization rate constants were eminently accelerated.
- Block copolymers were easy to be synthesized via modulating the monomer introduction sequence.

TBD catalyzed continuous flow ring-opening polymerizations of ε-caprolactone and δ-valerolactone were exemplified as the model investigation system of organocatalytic synthesis of polyesters in the simple PTFE tubular microreactor (MR). In contrast to the batch reactor (BR), significant benefits of utilizing continuous flow strategy were achieved including higher level control of molecular weights and molecular weight distributions as well as faster polymerizations (kapp(CL) = 0.00602 (MR) vs 0.00286 min−1 (BR); kapp(VL) = 0.159 (MR) vs 0.079 min−1 (BR)). Furthermore, more easily and efficiently block copolymerizations were conducted in the integrated-microreactor by sequential introduction of monomers to well-defined poly(δ-valerolactone)-block-poly(ε-caprolactone) and poly(ε-caprolactone)-block-poly(δ-valerolactone).

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