Scale Synthesis of Poly(butylene carbonate-co-terephthalate) and Its Depolymerization–Repolymerization Recycling Process

Development of biodegradable aliphatic–aromatic copolyesters has been widely accepted by society as a promising strategy to solve plastic pollution. Here, a kilogram-scale aliphatic–aromatic copolyester, poly(butylene carbonate-co-terephthalate) (PBCT), has been successfully synthesized using a 5 L steel reactor. The physical–chemical properties, including composition, microstructure, thermal properties, crystal structure, rheology behavior, mechanical properties, and water barrier property, were systematically investigated. The results illustrated that PBCT could be used as an ideal barrier packaging film material. In addition, the closed-loop recycling property of PBCT was preliminarily explored. The aromatic units of PBCT copolyesters were able to be recycled using the esterification byproduct, which consisted of methanol and dimethyl carbonate. The evolution of molar weights during the alcoholysis process indicated that PBCT could be completely converted to dimethyl terephthalate (DMT). The repolymerized PBCT prepared with the recycled DMT showed no significant property loss compared with the initial PBCT. This work provides a novel insight and direction for treating waste biodegradable polyesters, which could overcome the post-consumer plastic waste accumulation in the environment.