Sustainable Polythioesters via Thio(no)lactones: Monomer Synthesis, Ring‐Opening Polymerization, End‐of‐Life Considerations, and Industrial Perspectives

Abstract

As the environmental effects of plastics are of ever greater concern, the industry is driven towards more sustainable polymers. Besides sustainability, our fast‐developing society imposes the need for highly versatile materials. Whereas aliphatic polyesters (PEs) are widely adopted and studied as next‐generation biobased and (bio)degradable materials, their sulfur‐containing analogs, polythioesters (PTEs), only recently gained attention. Nevertheless, the introduction of S atoms is known to often enhance thermal, mechanical, electrochemical, and optical properties, offering prospects for broad applicability. Furthermore, thanks to their thioester‐based backbone, PTEs are inherently susceptible to degradation, giving them a high sustainability potential. The key route to PTEs is through ring‐opening polymerization (ROP) of thio(no)lactones. This Review critically discusses the (potential) sustainability of the most relevant state‐of‐the‐art in every step from sulfur source to end‐of‐life treatment options of PTEs, obtained through ROP of thio(no)lactones. The benefits and drawbacks of PTEs versus PEs are highlighted, including their industrial perspective.

An orthogonal O,S-CKA monomer for the introduction of thioester and/or thionoester functionalities by radical polymerization

“…To examine the copolymer degradation, as thionoester groups should be hydrolyzable under alkaline conditions, 39 copolymers poly(Sty 95.6 - co-O , S -BMDO 4.4 ) and poly(Sty 82.7 - co-O , S -BMDO 17.3 ) were subjected to basic hydrolysis using KOH in EtOH/H 2 O at 80 °C. This process greatly reduced the M n values of both copolymers, thereby demonstrating successful incorporation of thionoester linkages into the copolymer backbone in a relatively randomized manner (Fig.…”

Copolymerization Involving Sulfur-Containing Monomers

“…Previously, some excellent overviews with a focus on polythioesters and polythiocarbonates were presented. 40,42,43 Herein, we offer a more critical overview of the synthesis of S-containing polymers by copolymerization and multicomponent polymerization techniques involving at least one S-containing monomer. Particularly, achievements made in addressing the stereochemistry and the topological structure control via the design of well-defined catalysts, as well as the modulation of structure− property relationships of S-containing polymers, are introduced.…”

“… The thiol-based click reactions with dienes or diynes and MCP concerning S-containing monomers afford efficient strategies for the construction of S-containing polymers with complicated structures. , In addition, precisely controlling the main chain stereochemistry facilitates the formation of isotactic polymers with enhanced thermal and mechanical properties. Previously, some excellent overviews with a focus on polythioesters and polythiocarbonates were presented. ,, Herein, we offer a more critical overview of the synthesis of S-containing polymers by copolymerization and multicomponent polymerization techniques involving at least one S-containing monomer. Particularly, achievements made in addressing the stereochemistry and the topological structure control via the design of well-defined catalysts, as well as the modulation of structure–property relationships of S-containing polymers, are introduced.…”

Triazabicyclodecene: A versatile catalyst for polymer synthesis

“…As a result, many reactions applicable to esters and carbonates can also be adapted for these sulfur and phosphoruscontaining analogs. [151][152][153] TBD has successfully facilitated the ROP of sulfur and phosphorus-containing synthetic derivatives of esters and carbonates.…”