Preparation of Plant Polyphenols Nanoparticle Decorated <scp>MXene</scp> for High‐Performance Polyvinyl Alcohol Composites

ABSTRACT Developing high‐performance, multifunctional, and eco‐friendly polymer materials remains a huge challenge. In this work, through the oxidative self‐polymerization and self‐assembly of plant polyphenols gallic acid (GA) on MXene surface, GA nanoparticle decorated MXene (MX‐PGA) was synthesized and subsequently incorporated into poly(vinyl alcohol)/starch (PVA/ST) blend to fabricate PVA/ST/MX‐PGA composite. The abundant phenolic hydroxyl groups on MX‐PGA surface were capable of forming high‐density hydrogen bonds with PVA/ST chains, thereby constructing a dynamic crosslinking network. Under external tensile stress, the hydrogen bonds within this network underwent rupture and reformation. Consequently, at a MX‐PGA loading of 5 wt%, the tensile strength of PVA/ST/MX‐PGA composite reaches 160% of that of the unfilled PVA/ST blend. Notably, compared to unmodified MXene, MX‐PGA enabled the composite to exhibit simultaneously enhanced strength and toughness, significantly overcoming the traditional trade‐off between strength and toughness. Moreover, PVA/ST/MX‐PGA composite demonstrated enhanced antioxidant activity, UV‐blocking performance, and thermal stability. In summary, through the polyphenol nanoparticle modification of MXene, this work provides an effective strategy for the design and preparation of high‐performance and multifunctional PVA/ST composites, which holds promise for practical applications.