Preparation and Performances of Degradable Polybenzoxazine by Ring-Opening Metathesis Polymerization

Due to its outstanding properties, benzoxazine resin is widely used in the manufacturing of machinery, aerospace, and electrical products. However, once polybenzoxazine and its composites reach the end of their useful lives, their three-dimensional network structure and persistent cross-linking after curing pose challenges for degrading. To address this issue, our study focuses on incorporating 2,3-dihydrofuran (DHF)-containing cleavable bonds into the cross-linked network of benzoxazine (PH-5n2m) containing the structure of norbornene by ring-opening metathesis polymerization (ROMP). Due to the unique chemical structure of norbornene and the flexibility of the DHF chain segment, poly(PH-5n2m/DHF-x) exhibits remarkable thermal stability and improved toughness compared to poly(PH-5n2m). Additionally, under weak acid conditions, the PH-5n2m/DHF-50/CF composite can degrade fully in less than 10 h, facilitating the nondestructive recycling of the carbon fiber. This work presents a novel approach to the development of thermosetting resins with high thermal stability, improved toughness properties, and degradability, offering promising prospects for sustainable materials in various industries.