Can a polymer be reinforced without loss of its toughness? Are there any modifiers or approaches that not only reinforce but also toughen a polymer? Can the stiffness and toughness of a polymer be simultaneously improved? These have been a major challenge in modification of polymeric materials. Here we present our recent work on reinforcing polyvinyl alcohol (PVA) with improved toughness via a bioinspired strategy. Melamine was employed to reinforce PVA through hydrogen bond assembly. It has been shown that addition of small amount (1.0 wt%) of melamine significantly improves its Young’s modulus (i.e. stiffness), yield strength, tensile toughness and extensibility. The presence of melamine increases its glass transition temperature (Tg) and especially thermal stability. Our findings have shown that small organic molecules can simultaneously reinforce and toughen polymers effectively through hydrogen bond assembly. It will bring about a general methodology enabling reinforcement of polymers with both improved stiffness and toughness for the first time.
