Engineering an organic-inorganic hybrid interface with abalone shell-derived aragonite platelets and PEI for enhanced carbon fiber/epoxy composites

Using PEI as a binder to stably anchor natural aragonite sheets on CFs, creating a novel organic-inorganic hybrid interface. • The composite exhibited enhancements in IFSS, ILSS, and impact strength by 42.03%, 25.73%, and 46.81%, respectively. • The fractured surface exhibited unique roughness and fragmentation, which suppressed fiber pull-out while dissipating impact energy. Carbon fiber-reinforced polymer composites (CFRPs) require effective interfacial design to achieve both high strength and toughness. Here, polyethyleneimine (PEI) was used to bridge and anchor abalone shell-derived aragonite platelets (ASP) onto polydopamine-modified carbon fibers, forming an organic-inorganic hybrid interphase. PEI facilitated ASP immobilization, while the resulting modification increased the fiber surface energy by 78.9% without compromising the intrinsic fiber strength. The interfacial shear strength (IFSS), interlaminar shear strength (ILSS), and impact strength of the resulting CFRPs reached 102.89 MPa, 101.16 MPa, and 91.52 kJ/m², respectively, all exceeding those of the unmodified and individually modified systems. SEM observations supported the improved interfacial adhesion, accompanied by a rougher and more fragmented impact-fractured morphology. The PEI-ASP hybrid interphase improves interfacial load transfer and suppresses premature debonding, while the rigid ASP platelets may impede local crack propagation, promoting more distributed damage and greater impact-energy dissipation. The direct and efficient utilization of such natural aragonite platelets on CFs provides a simple and promising strategy for enhancing the overall performance of CFRPs. Download: Download high-res image (226KB) Download: Download full-size image