Homogenizing Blends of Cross-linked Polymers by Interfacial Exchange Reactions.

Obtaining homogeneous blends of two covalently cross-linked polymers by mechanical mixing is not possible due to their permanent network topologies. Here, we demonstrate an effective route to prepare polymer blends from the common cross-linked epoxidized natural rubber (ENR) and epoxy resin vitrimer (EV) by mechanical mixing. Interfacial exchange reactions between these two networks occur by a dynamic transesterification. The as-prepared ENR-EV blends show excellent mechanical strength, extensibility, and thermal stability. Moreover, they also show typical vitrimeric properties, including self-healing, welding, and reprocessability. This work demonstrates a large-scale preparation of vitrimeric materials with high performance and versatility from commercially available polymers and affords a promising strategy to recycle both waste rubbers and resins.