Microscopic Fracture Behavior and Thermal-Mechanical Properties of Biowaste-Modified CaCO3/rGO-Carbon Fiber Epoxy Composites for Structural Applications

Carbon fiber-reinforced polymer (CFRP) composites have gained significant attention for their lightweight and excellent mechanical properties; however, pure epoxy resins alone cannot meet the demands of high-performance composites. The influence of (CaCO₃/rGO) CACG-based hybrid filler on CFRP composites' thermal and mechanical properties was systematically investigated. Fracture analysis was performed using an in situ notch tensile test in a field emission scanning electron microscope. At the same time, finite element analysis was employed to predict the stress distribution in each ply. The CACG3/CFRP (1 wt% loading of GO) composite showed higher mechanical, viscoelastic, and thermal properties compared to other composites, with tensile and flexural strength enhancements of ~45.33% and 76.17%, respectively. Incorporating the hybrid nanofiller significantly improved the composites' glass transition temperature (T_g) and thermal stability. This study provided valuable insights into the design and development of structural-functional CFRP composites, paving the way for their potential applications in aerospace and other high-performance engineering fields.