Relationships between Sequential Strcture and Physicochemistry Performance for CO2-derived Semi-aromatic Poly(carbonate-ester) Terpolymers

Poly(propylene carbonate) (PPC), the alternating copolymers o f carbon dioxide (CO 2 ) and propylene oxide (PO), is a commercialized biodegradable plastic with excellent transparency, low cost and full biodegradability. Its flexible, dense chains provide outstanding gas-barrier performance for food and pharmaceutical packaging. In order to further enhance the application potential of PPC in terms of thermal stability and gas barrier performance, terpolymerization of CO 2 /PO/phthalic anhydride is conducted via both one-pot/two-step and one-pot/one-step methods using a metal-free catalytic system. Polycarbonate-polyester terpolymers (PPC-P) with different sequence structures but similar molecular weight and approximately 43% polyester content were successfully synthesized by adjusting catalyst ratios, reaction temperature, and monomer feed ratios. The thermal degradation behavior of PPC-P was investigated using TG/IR and Py-GC/MS techniques. Furthermore, a comprehensive study was conducted to examine the influence of sequence structures on the thermal stability, mechanical properties, oxygen/water barrier performance, and alcoholysis behavior of PPC-P materials. The results demonstrates that the sequence structure of polymer significantly influences on its thermal stability, gas barrier properties and alcoholysis behavior. This work not only elucidates the relationship between polymer sequential structure and performance, but also provides the foundation for the development of biodegradable materials in food and pharmaceutical applications.