Nanoplatelet orientation and Young’s modulus of graphene/phenoxy nanocomposites

Abstract We report on the development of phenoxy-graphene nano-composite fibres for improving the toughness of thermoset composites. In this paper, a systematic experimental investigation into the underlying mechanisms of graphene nanoplatelets (GNP) reinforcement of phenoxy nanocomposite fibres prepared via melt spinning. The analysis reveals a tangential orientation of GNP in the outer layer of the fibres, while such orientation is absent in the fibre core region. We show that the relative size of the fibre sheath depends on process variables and exhibits a linear relationship with the modulus of GNP (Ef) obtained via theoretical analysis using simple rule of mixtures (RoM). This is because the area ratio (AR) is proportional to the orientation degree (η0) of GNP. This indicates that the enhancement of the Young’s modulus of fibres is mainly originated from the increased AR of the fibre sheath layer where the orientation of GNP is more regular, resulting in variations in the stress transfer efficiency between GNP and phenoxy matrix in the fibre sheath and core regions.