Radical ring-opening polymerization of sustainably-derived thionoisochromanone.

We present the synthesis, characterization and radical ring-opening polymerization (rROP) capabilities of thionoisochromanone (TIC), a fungi-derivable thionolactone. TIC is the first reported six-membered thionolactone to readily homopolymerize under free radical conditions without the presence of a dormant comonomer or repeated initiation. Even more, the resulting polymer is fully degradable under mild, basic conditions. Computations providing molecular-level insights into the mechanistic and energetic details of polymerization identified a unique S,S,O-orthoester intermediate that leads to a sustained chain-end. This sustained chain-end allowed for the synthesis of a block copolymer of TIC and styrene under entirely free radical conditions without explicit radical control methods such as reversible addition-fragmentation chain transfer polymerization (RAFT). We also report the statistical copolymerization of ring-retained TIC and styrene, confirmed by elemental analysis and energy-dispersive X-ray spectroscopy (EDX). Computations into the energetic details of copolymerization indicate kinetic drivers for ring-retaining behavior. This work provides the first example of a sustainable feedstock for rROP and provides the field with the first six-membered monomer susceptible to rROP, expanding the monomer scope to aid our fundamental understanding of thionolactone rROP behavior.

Correction: Radical ring-opening polymerization of sustainably-derived thionoisochromanone.

[This corrects the article DOI: 10.1039/D2SC06040J.].

Rapid Synthesis of Chemically Recyclable Polycarbonates from Renewable Feedstocks.

We report the rapid, one-pot synthesis of functional polycarbonates derived from renewable alcohols (i.e., glucose tetraacetate, acetyl isosorbide, lauryl alcohol, and ethanol) and a cyclic carbonate bearing an imidazolecarboxylate. This tandem functionalization/ring-opening polymerization strategy can be performed on multigram scale and eliminates the need for rigorous purification and specialized equipment. A wide range of glass transition temperatures (Tg) was accessible from these renewable pendant groups (>75 °C Tg window). We also synthesized several statistical copolycarbonates to show the thermal properties can be tailored with this tandem method. Additionally, we demonstrate a circular polymer economy via chemical recycling to a cyclic carbonate precursor. This work may facilitate development of sustainable polycarbonates with tailored properties that work toward eliminating plastic waste streams.