A study on the tailoring of interfacial shear strength between graphene and polymer by addressing defects in graphene

A molecular dynamics simulation study on the interfacial strengthening between defected graphene and polypropylene matrix is implemented. As intrinsic defects in single layer graphene, oxidation, Thrower-Stone-Wales(TSW) defect, and Adatom defect are considered. On the transversely isotropic nanocomposites unit cell embedding different defected graphene, transversely isotropic stress-strain relations are predicted from quasi-static tensile and shearing simulation. At the same time, the degradation of graphene by the addressed defects is studied to elucidate the degradative feature of the defects. Since all the defects considered in this study is found to decrease tensile and shear properties of graphene, tensile behavior of graphene reinforced nanocomposites is degraded according to the density of each defect. In shearing of nanocomposites which involved face-to-face interfacial sliding of graphene and polymer, however, it is found that the defected graphenes show better interfacial load transfer,thus, enhaced shear moduli. To establish structure-to-property relationship of defected graphene reinforced composites, surface roughness induced by the addressed defect is calculated and correlated with the shear moduli of nanocomposites.