Fully Chemical Recyclable Poly(γ-butyrolactone)-based Copolymers with Tunable Structures and Properties

The emerging chemical recyclable polymers, such as poly(γ-butyrolactone) (PGBL) and poly((R)-3,4-trans six-membered ring-fused GBL) (P((R)-M)), provide a good solution to the plastic pollution. However, these homopolymers suffer from limited structures and properties. Herein, we reported a fully chemical recyclable copolymer P(GBL-co-((R)-M)) through ring-opening copolymerization (ROCOP) of GBL and (R)-M. By employing organomagnesium as the catalyst and regulating the reaction conditions, the chemical structures of copolymers were well-controlled (GBL content=13%–78%, M_n=6560–15600 g/mol, Ð_M=1.08–1.59). The resultant P(GBL-co-((R)-M)) exhibited fully chemical recyclability, which rapidly and quantitatively depolymerized into initial GBL and (R)-M monomer through chemolysis. By varying GBL content, tunable thermal properties were achieved for P(GBL-co-((R)-M)). The onset decomposition temperatures of copolymers varied from 193 °C to 234 °C. A linear evolution of glass transition temperature (T_g) of P(GBL-co-((R)-M)) versus GBL content was obtained as following equation of T_g = −1.06 × GBL mol% × 100 + 39.6. We hope that the reported fully chemical recyclable copolymers with tunable structures and properties would serve as the candidate material for sustainable applications.