Toughening of Intraply Carbon/Kevlar Hybrids With Nanosilica and Nanoclay: Mode‐I and Shear Behavior

ABSTRACT This study investigates the influence of nanosilica (NS) and nanoclay (NC) additives on the Mode‐I interlaminar fracture toughness (G _IC ) and interlaminar shear strength (ILSS) of intraply woven carbon/Kevlar fiber reinforced epoxy (CKFRE) composites. The toughening mechanisms were observed using a scanning electron microscope and an optical microscope. Results show that both nanoparticle type and concentration critically affect interlaminar performance. At optimum loadings, CKFRE/NC composites exhibited up to 19.1% (2 wt%) and 17.2% (4 wt%) increases in G _IC , while CKFRE/NS achieved a 48.4% improvement at 0.5 wt%. ILSS performance followed a similar trend, with enhancements of 21.6% (2 wt% NC) and 25.7% (0.5 wt% NS). These improvements were attributed to synergistic toughening mechanisms, including crack deflection, particle‐induced crack pinning, fiber bridging, and enhanced fiber‐matrix stress transfer. However, higher nanoparticle concentrations led to agglomeration, resin‐rich zones, and a reduction in interfacial bonding efficiency, resulting in deterioration of the properties. The findings highlight optimal concentration ranges of 2–4 wt% NC and 0.5–1 wt% NS, providing valuable design guidelines for next‐generation hybrid composites with improved interlaminar properties for aerospace, defense, and automotive applications.