Terpolymerization of Epoxide with Carbon Dioxide and 1,8-Naphthalic Anhydride Enabling Improved Performance of CO ₂ -Polymeric Materials

Poly(propylene carbonate) (PPC), synthesized via copolymerization of carbon dioxide (CO 2 ) and propylene oxide (PO), exhibits exceptional biodegradability, barrier properties, and biocompatibility, making it suitable for industrial applications such as food packaging and agricultural mulch films. However, its broader utilization is limited by a low glass transition temperature and low tensile strength. In this study, 1,8-naphthalic anhydride (NA) is introduced as a rigid monomer into the polycarbonate backbone, aiming to enhance the performance of CO 2 -polymers. The random terpolymerization of PO, NA, and CO 2 can be achieved using a binary catalyst system comprising triethyl borane (TEB) and bis(triphenylphosphine)iminium chloride (PPNCl), producing statistical CO 2 -polymers with variable components. Notably, CO 2 -polymers with high molecular weights can be obtained via an extra chain extension procedure using diisocyanate. Particularly, these CO 2 -polymers demonstrated superior properties, achieving a glass transition temperature of 109.9 °C and a tensile strength of 104.4 MPa. Interestingly, molecular dynamics simulations revealed that the π–π stacking interaction between naphthalene rings is the primary factor contributing to the enhanced performances of CO 2 -polymers.