Collaborative improvement of interfacial properties of carbon fiber/epoxy resin composites through modulus/toughness matching and gradient interface

Abstract

The interface is crucial for the mechanical properties of composite which is tightly linked to the microstructure of CF surface and resin matrix. However, the modulus mismatch between CF and resin leads to stress concentration and poor interfacial performance. This study proposes a bidirectional structural design strategy aimed at optimizing the interfacial performance of CF/epoxy composites from the perspective of interfacial construction and modulus matching. An organic-inorganic three-dimensional hybrid particle <PDI,GO> (the notation <PDI,GO> indicates a composite formed between PDI and GO through both chemical and physical interactions) was synthesized to enhance the modulus and toughness of resin, as well as the chemical bonding, mechanical entanglement and wettability with resin of CF surface. Compared to the original and single pathway (either the CF or resin), the transverse tensile strength of the bidirectionally modified composites increased by 68.4%, 31.2% and 18.0%, and the interlaminar shear strength increased by 23.6%, 8.5%, 18.6%, respectively. Furthermore, a comprehensive exploration of synergistic reinforcement mechanisms and stress dispersion patterns at the composites was conducted. This bidirectional structural design strategy provides a new avenue for the next-generation high-performance composites in the fields of aerospace, rail transit and so on.