Stiffness of In-Situ Formed Interleaving Polymeric Nanofiber-Epoxy Nanocomposites

This study proposes a facile, but precise method to back-calculate the effective
modulus of nanocomposite interleaving plies. Adaptation of a conventional dry reinforcement resin film infusion (RFI) approach allows interleaving neat epoxy layers (NE) with the epoxy-infused nanofibrous plies (XE) of constant thickness.
The final cured nanocomposite laminate thus has the form (NE/XE)n, where “n”
denotes the number of the repeats and enables clear distinction of the nanocomposite interlayers through the thickness. Mechanical testing of neat epoxy and laminated nanocomposite specimens can be coupled with the classical lamination theory for back-calculating in-plane elastic modulus of the individual epoxy infused nanofibrous plies (EXE). Finite element analysis (FEA) and testing the laminated nanocomposite subject to flexural loading (3-point bending) are proposed to validate the analytically back-calculated EXE. It is shown that the FEA prediction incorporating EXE and testing for flexural modulus of (NE/XE)20 laminated nanocomposites correlate well and the results are within 5%. This finding suggests that the back-calculation scheme reported herein would be attractive for accurately determining the properties of an individual nanocomposite building block layer. The proposed framework is beneficial for modelling laminated structural composites incorporating XE-like nanocomposite interlayers.