Cross-linked polymers based on B–O bonds: synthesis, structure and properties

Introducing B–O bonds into traditional polymer networks can produce polymer materials with novel structures and unique properties. In particular, the higher bond energy of B–O bonds can significantly improve the thermal stability of the polymers, meanwhile, their sensitivity to heat and media can realize the reprocessing and recycling of the polymer materials with cross-linked structures. In recent years, cross-linked polymers based on B–O bonds with different structural characteristics and functions have been developed, which has greatly enriched the field of boron-containing crosslinked polymers. Over the past decade, our research has focused on boric/boronic acid and their derivative modified phenolic resins, and a series of ablative resistant polymers and dynamic crosslinked polymers with excellent properties have been developed. In this review, the progress of research on cross-linked polymers based on B–O bonds with different structures and functions, and the synthesis, structure and properties are highlighted. The basic principles for improving the thermal stability of the polymers and achieving the regeneration of crosslinked polymers based on the B–O bonds are elaborated. Future challenges and development trends for cross-linked polymers based on B–O bonds are also critically discussed.