Upcycling of waste polycarbonate to recyclable Poly(carbonate-imines) with exceptional thermal properties and unprecedented flame retardancy.

Upcycling of Waste Polycarbonate to Recyclable Poly(carbonate-imines) with Exceptional Thermal Properties and Unprecedented Flame Retardancy. [Display omitted] • Waste polycarbonate (WPC) was converted into a WPC-derived amine (WPC-NH 2) • Poly(carbonate-imines) (PCIs) were prepared based on WPC-NH 2 and dialdehydes. • The PCIs demonstrate exceptional thermal and unprecedented flame-retardant properties. • The PCIs exhibited stress relaxation and reprocessability. • The structure-hydrolytic stability relationship of PCIs was discussed. This study introduces an innovative method for upcycling waste polycarbonate (WPC) into poly(carbonate-imines) (PCIs), which exhibit exceptional thermal properties and unprecedented flame retardancy. Utilizing a novel insertion reaction of 2-((4-nitrophenoxy)methyl)oxirane with WPC, followed by hydrogenation, we have synthesized WPC-derived amine (WPC-NH 2). This amine is further reacted with bifunctional aldehydes to form PCIs that not only meet vitrimer criteria (characterized by stress relaxation and thermal reprocessability through imine metathesis) but also demonstrate superior thermal stability (T g up to 228 °C) and low thermal expansion (42 ppm/°C). Importantly, these PCIs achieve a UL-94 V-0 rating and exhibit significantly reduced total heat release (11.8 KJ/g), positioning them as prime candidates for sustainable, high-performance materials. The synthesis process supports recycling, showcasing a practical approach to the degradation of PCI-based CFRPs and recovery of intact carbon fibers, underscoring the environmental benefits of this method. [ABSTRACT FROM AUTHOR]