Macromolecular Grafting of Untreated Glass Fiber: Facile Preparation and Application in High‐Performance Polyolefin Composites

ABSTRACT Surface modification of reinforcing inorganic fillers with polymer chains has attracted great attention since it promises high‐performance polymer composites. However, the macromolecular grafting of inorganic fillers in a facile manner still remains challenging due to the low reactivity of fillers towards polymer chains, often requiring complex procedures. To address this, we developed a facile strategy to directly graft ethylene‐vinyl acetate copolymer (EVA) onto untreated glass fiber (GF) via robust and efficient transesterification between ester groups in EVA and silanols on GF. Using a one‐step reactive blending approach, we then prepared high‐density polyethylene (HDPE) composites reinforced with in situ generated EVA‐grafted GF (EVA‐g‐GF). The modification improved the dispersion of EVA‐g‐GF within the HDPE matrix, attributed to enhanced interfacial interactions. Notably, the mechanical properties of HDPE/EVA‐g‐GF composites were substantially enhanced relative to pristine HDPE. The tensile strength, elastic modulus, and impact strength increased by 13.3%, 51.9%, and 23.2%, respectively, while maintaining a high elongation at break of 1404%. In summary, this work provides a convenient route for macromolecular grafting of inorganic fillers and the preparation of high‐performance polymer composites with enhanced interfacial interactions, which feature readily available raw materials, a simple process, and excellent mechanical properties.