Direct Mechanochemical Aryl Amination of Polystyrene for Creep Resistant Imine Elastomers

Imine-based covalent adaptable networks (CANs) hold promise for the development of recyclable thermoset materials, but due to low barriers for dynamic exchange, such networks typically suffer from significant material creep. Incorporating linear polymers into imine CANs can improve creep resistance by introducing physical crosslinks, while reactive variants further mitigate through chemical crosslinks. Herein, we directly aminate polystyrene (up to 1.1 mol%) using ball mill grinding mechanochemistry with liquid-assisted grinding for inclusion into dynamic materials. This post-polymerization modification technique allows us to avoid excess solvent while preserving high molar mass. Incorporating aminated PS (aPS) in representative polyimine elastomers enhances creep resistance relative to unmodified PS, while generally maintaining comparable mechanical properties. These findings establish waste PS grafted with low densities of reactive primary amines as an effective additive for improving deformation resistance in polyimines, thus offering a route to give post-consumer plastic waste renewed value.