Facile Interface Incorporation of Trace Amounts of Short‐Cut Aramid Fibers for Enhanced Laminated Composites

ABSTRACT The inherent poor interlaminar toughness of glass fiber‐reinforced polymer (GFRP) composites severely limits their application reliability in structural engineering. Particularly under interlaminar stress or impact loads, delamination damage becomes the primary failure mode. To address this critical issue, this study developed a synergistic toughening strategy, which involves introducing an ultra‐low content of aramid fiber/polyphenylene sulfide (AF/PPS) composite paper as an interlayer and combining it with the KH560 silane coupling agent to enhance the interface performance. The AF/PPS paper prepared by the wet‐lay process has good compatibility with the resin prepreg and can be seamlessly embedded as an interlayer in the conventional hot‐press molding process without significantly increasing the manufacturing complexity. The results show that adding only 2% AF can significantly improve both the strength and toughness of the GFRP composites: the flexural strength and tensile strength are 500 MPa and 394 MPa respectively. The flexural fracture displacement and tensile fracture elongation increase by 25.7% and 34.6% respectively, while the energy absorption capacity increases by 59.3%. Meanwhile, it exhibits excellent performance in impact resistance and shear resistance, reaching 117 KJ/m 2 and 20 MPa respectively, with increases of 37.6% and 47.8% respectively. Experiments indicate that precisely customizing the interlaminar structure with an ultra‐low content of short fibers can effectively improve the mechanical properties of GFRP, providing an industrially feasible technical approach to overcome the common trade‐off between strength and toughness in GFRP.