Recyclable, malleable, tunable cross-linked elastomers based on boroxines and acetoacetyl

A variety of dynamic covalent bonds have been exploited to build covalent adaptable networks (CANs), which is considered to be an effective approach to recycle thermosets and has gained widespread attention. However, how to prepare CANs with tunable properties via an effective strategy is still unsatisfactory and challenging. Here, acetoacetyl was grafted into commercial polybutadiene and utilized as a platform to tune the properties of boroxine-based CANs. The chemical structures were characterized clearly. The obtained CANs named as PBKB-x was demonstrated not only to be recyclable through multiple routes, but also to exhibit malleability and shape memory effect. Compared with other CANs, the performances of PBKB-x were tunable based on the versatile acetoacetyl, including mechanical properties, light irradiation behaviors, and surface properties, which was important for improving the practical application value of CANs.