Organocatalyzed Synthesis and Degradation of Functionalized Poly(4-allyloxymethyl-β-propiolactone)s

The chemical synthesis of degradable poly(β-hydroxyalkanoate) (PHA) produced by microorganisms allows the control of the solubility, crystallinity, hydrophobicity, degradability, thermal, and mechanical properties by introducing functionality on the side chain. Herein, we synthesized a PHA derivative containing a pendant allyl group via the anionic ring-opening polymerization of a 4-allyloxymethyl-β-propiolactone (AMPL) monomer, which was prepared via the carbonylation of allyl glycidyl ether. The AMPL monomer was subjected to various organocatalysts in bulk to yield poly(4-allyloxymethyl-β-propiolactone) (PAMPL) with controllable molecular weight and dispersity. The prepared PAMPL polymers were characterized via 1H and 13C NMR, gel permeation chromatography (GPC), differential scanning calorimetry (DSC), and matrix-assisted laser desorption/ionization-time-of-flight (MALDI-TOF) analyses. A photoactivated thiol-ene reaction allowed the postpolymerization modification of PAMPLs with varying substituents. Functionalized PAMPL polymers degraded under chemical and thermal conditions, and importantly, cross-linked PAMPL films degraded during exposure to soil and seawater under a wide range of degradation kinetics. This study provides the future potentials of the chemically synthesized and functionalized PHA for replacing conventional petroleum-derived polymers.