Poly(imine-amide) Hybrid Covalent Adaptable Networks via in situ Oxidation Polymerization

Polyimine represents a rapidly emerging class of readily accessible and affordable covalent adaptable networks (CANs) that have been extensively studied in the past few years. While being highly malleable and recyclable, the pioneering polyimine materials are relatively soft and not suitable for certain applications that require high mechanical performance. Recent studies have demonstrated the possibility of significantly improving polyimine properties by varying its monomer building blocks, but such component variations are usually not straightforward and can be potentially challenging and costly. Herein, we report an in situ oxidation polymerization strategy for preparation of mechanically strong poly(imine-amide) (PIA) hybrid CANs from simple amine and aldehyde monomers. By converting a portion of reversible imine bonds into high-strength amide linkages in situ , the obtained hybrid materials exhibit gradually improved Young’s modulus and ultimate tensile strength as the oxidation level increased. Meanwhile, the PIAs remain reprocessable and can be depolymerized into small molecules and oligomers similar as polyimine. This work demonstrates the great potential of the in situ transformation strategy as a new approach for development of various mechanically tunable CANs from the same starting building blocks.