Epoxy composites integrated with functionalized wet‐milled graphitic nanoparticles: Featuring enhanced mechanical performance and in‐plane fracture resistance

Abstract Composites made of epoxy‐based systems are popular in many engineering applications because of their enhanced mechanical performance, fatigue properties, and other physical and thermal properties, but their low fracture toughness can limit their usefulness in high‐performance structural applications. This study aims to enhance the fracture properties of epoxy‐based composites by adding cost‐effective ball‐milled graphitic nanoparticles. Herein, dry ball milling for 15 and 48 h is done to produce ball‐milled graphite (BMG) nanoparticles. A significant reduction in particle size is achieved after 15 h of dry milling. Interestingly, a similar reduction in particle size is achieved for BMG (~258 nm) when wet ball milling for 3 h is performed. These BMGs were silanized (SBMG@3) and incorporated into the epoxy network. We found even at a higher loading level of SBMG@3, the resulting nanocomposites exhibited a significant improvement in fracture toughness (~2.47 MPa m^1/2) and energy (~1.55 kJ/m²). This improvement was attributed to the upliftment of the in‐plane crack propagation resistance of the nanocomposites primarily offered by SBMG@3 due to coagulated interfacial interaction with the epoxy network that effectively hindered the propagation of the crack by providing numerous sites for energy dissipation, leading to improved fracture toughness. Our results demonstrate that SBMG@3 has great potential for improving the fracture toughness and energy of epoxy‐based composites, making them suitable for various industrial applications. Highlights Synthesized cost‐effective 2D carbon nanofillers via high‐energy ball milling. To overcome the re‐agglomeration effect wet ball milling is performed. Transformation of natural graphite to BMG with sizes of ~258 nm. K_IC and G_IC improve to ~2.47 MPa m^1/2 and 1.55 kJ/m², respectively, for ECSB1. FS and FM of the epoxy nanocomposites enhanced by ~43.69% and ~51.64%.