Reinforcement of Polyimine Covalent Adaptable Networks with Mechanically Interlocked Derivatives of SWNTs

There is an urgent need for new approaches to reduce the environmental impact of plastics. One approach is to enhance recyclability. Covalent adaptable networks (CANs), where crosslinks are chemically reversible, offer an attractive alternative to thermoset materials. Another option is to strengthen polymers using nanofillers, to reduce the amount of material needed. In this regard, single‐walled carbon nanotubes (SWNTs) are excellent candidates as fillers due to their extreme strength‐to‐weight ratio and dimensionality. Here, SWNTs functionalized as mechanically‐interlocked derivatives (MINTs) are shown to significantly improve the mechanical properties of polyimine (PI) CANs, with close to optimal efficiency. Enhancements in both stiffness and ultimate strength, approaching 100% load transfer considering the SWNT loading, are observed for PI MINT, while composites made with pristine SWNTs exhibit poor improvement. The PI MINT CANs can be recycled both thermally and chemically without compromising their mechanical properties. Finally, prototype carbon fiber PI MINT laminar composites are also fabricated and characterized, demonstrating a significant increase in their mechanical properties. Polyimine covalent adaptable networks (PI CANs) are reinforced with mechanically interlocked derivatives of SWNTs (MINTs). The covalent linkage of the macrocycles to the PI CAN allows close to optimal load transfer to the SWNTs. The nanocomposites are recyclable both thermally and chemically. Carbon fiber PI MINT laminar composites also show very significant enhancement of their mechanical properties.