An investigation on the reinforcement mechanism of the nano‐sized carbonaceous filled epoxy‐glass fiber hybrid‐composites through analysis of fracture surfaces

The objective of this work was to investigate the influence of delamination degree of the graphite on the mechanical properties of glass fiber/epoxy composite. To aim this, graphene and highly expanded graphite (HEG) nanofillers were synthesized using intensive ultrasonic method and were added to the epoxy and also glass fiber/epoxy composite, separately. Subsequently, tensile, flexural and impact strength of prepared samples were studied. Furthermore, the lateral size and dispersion quality of synthesized fillers in the epoxy matrix was inspected through using field emission scanning electron microscopy. Mechanical results demonstrated an enhancement by addition of both synthesized nanofillers to both nanocomposites and hybrid‐composites. Highest increment rate of tensile strength was related to the nanocomposites containing 0.5 wt% nanofillers in which 61 and 51% enhancement for graphene nanoplate and highly expanded graphite loaded samples, respectively, was observed compared with the neat epoxy. It was found that, degree of delamination and dispersion of graphite platelets has a fundamental influence on the mechanical properties. In addition, fracture surface of epoxy nanocomposites and hybrid‐composites were inspected to study the toughening mechanism. POLYM. COMPOS., 39:E2460–E2471, 2018. © 2018 Society of Plastics Engineers