Three-roll milling exfoliated graphite nanoplatelets enhanced epoxy resin matrix-octahedral spinel modified carbon fiber composites: Preparation, microstructure, and mechanical properties

This study aims to enhance the mechanical properties of epoxy resin (EP)-based carbon fiber (CF) composites. Graphite nanoplatelets (GNPs) obtained from the exfoliation of expanded graphite (EG) were uniformly dispersed in EP using three-roll milling (TRM) technology, ensuring the GNPs were well integrated with the EP matrix. Additionally, the surface modification of CF with octahedral magnesium-aluminum (MA) spinel was investigated to improve the adhesion between EP and CF. The results showed that when GNPs were incorporated at 1 wt% of EP, the resulting GNPs reinforced EP matrix CF composites (GNPs-EP/CF) exhibited enhancements of 26% and 12% in flexural and tensile strengths, respectively, compared to EP/CF composites. Furthermore, CF modified with a 1.5 wt% of MA solution produced octahedral MA-spinel-modified CF bonded to the epoxy resin matrix reinforced with TRM-exfoliated GNPs, resulting in composites (GNPs-EP/MA-CF), which demonstrated a 20.2% and 14.6% increase in flexural and tensile strengths, respectively, over GNPs-EP/CF composites. This research expands the scope of carbon fiber by functional oxides with special structures and provides a theoretical foundation for developing advanced materials and technologies for aviation applications.