Bio-inspired fabrication of “brick-and-mortar” interphase in carbon fiber/epoxy composites with significantly improved high-temperature durability

The application of carbon fiber–reinforced polymer (CFRP) composites in high-temperature environments was hindered by the bottleneck of poor interfacial performance between carbon fiber and epoxy resin at elevated temperatures. In this work, a sophisticated “brick-and-mortar” interphase, inspired by the structure of nacre, was produced through an industrialized roll-to-roll process. The resulting interphase comprised both inorganic and organic components, namely graphene oxide (GO) and amino-functionalized polyetherimide (APEI), respectively. At 180 ℃, the APEI-GO@carbon fiber (CF)/epoxy (EP) composite showed significant improvements in both interfacial shear strength (IFSS) and transverse fiber bundle tensile (TFBT) strength, with increases of 91.2% and 144.4%, respectively, compared to desized CF/EP composites. These enhancements were attributed to synergistic reinforcement facilitated by strengthened interaction and interphase. Furthermore, the “brick-and-mortar” interphase demonstrated a strong moisture barrier effect, enabling the composite to retain good ILSS (92.8%) after 70 days of hydrothermal aging. The proposed bio-inspired strategy for constructing “brick-and-mortar” interphase with excellent thermostability shed fresh insights into the industrialized design and fabrication of CFRP composite with outstanding high-temperature durability. Graphical Abstract