Bioinspired Strategy to Reinforce PVA with Improved Toughness and Thermal Properties via Hydrogen-Bond Self-Assembly.

Despite the high strength and stiffness of polymer nanocomposites, they usually display lower deformability and toughness relative to their matrices. Spider silk features exceptionally high stiffness and toughness via the hierarchical architecture based on hydrogen-bond (H-bond) assembly. Inspired by this intriguing phenomenon, we here exploit melamine (MA) to reinforce poly(vinyl alcohol) (PVA) via H-bond self-assembly at a molecular level. Our results have shown that due to the formation of physical cross-link network based on H-bond assembly between MA and PVA, yield strength, Young's modulus, extensibility, and toughness of PVA are improved by 22, 25, 144, and 200% with 1.0 wt % MA, respectively. Moreover, presence of MA can enhance the thermal stability of PVA to a great extent, even exceeding some nanofillers (e.g., graphene). This work provides a facile method to improve the mechanical properties of polymers via H-bond self-assembly.