Strong and tough octyl enamine-grafted polyvinyl alcohol with programmable shape deformation via simple soaking treatment

Abstract

Devising shape-configurable polymeric materials with high strength, large ductility, and great toughness is highly challenging and ever-increasingly desired. Here, octyl enamine-grafted polyvinyl alcohol with a sheath–core structure (AAPVA_x–OA) was prepared by soaking treatment of acetoacetylated polyvinyl alcohol (AAPVA_x) in the presence of octylamine (OA). The octyl enamine-grafted sheath is stiffer than the ungrafted core in AAPVA_x–OA possibly due to the strong hydrogen bonding. The mechanical properties of AAPVA_x–OA are superior to those of AAPVA_x–JOA, synthesized by solution casting of the blends of AAPVA_x and OA, since the hard-sheath–soft-core structure contributes to the stress transfer and energy dissipation of AAPVA_x–OA upon stretching. Moreover, AAPVA_x previously printed with octyl enamines in the predetermined areas can be programmed into the corresponding shapes in the presence of water. We believe that this work provides a new perspective for designing polymeric materials with high mechanical properties and shape-configuration ability using a simple soaking strategy, which can be implemented in other cases as well.