CO 2 -Based Polyalkenamer- g -Polycarbonate Graft Copolymers: One-Step Synthesis and Application as Highly Effective Polyolefin/Polycarbonate Compatibilizers

Integrating emerging biodegradable CO2-based poly(propylene carbonate) (PPC) with commodity polyolefins, the most widely used traditional plastics, to explore their mechanical recycling is highly significant as it not only promotes the circular economy but also fuels the large-scale development of PPC itself. However, their inherent thermodynamic incompatibility, stemming from distinct chemical structures and polarities, remains a critical barrier. Herein, we introduce a potent compatibilizer, which is a polyalkenamer-g-polycarbonate graft copolymer synthesized through a facile and efficient one-step polymerization to effectively bridge this immiscible interface between PPC with polyolefins including high-density polyethylene (HDPE) and isotactic polypropylene (iPP). This one-step strategy allows a diverse design of polyalkenamer backbones and polycarbonate side chains, with adjustable lengths and a maximum molecular weight of 480 kg mol–1. Adding 2 wt % of this graft copolymer to HDPE/PPC or iPP/PPC blends simultaneously enhances both elongation at break and tensile strength, boosting tensile toughness to 18-fold and 23-fold, respectively.