The evolution of the filament morphology resulting from isothermal curing of the resin is studied next and both TP and NF concentration profiles evaluated by Raman spectroscopy are presented. Subsequently, blend microstructures resulting from RIPS, involving the nanofillers, are discussed and correlated with the composition profiles. Finally, the proposed concept is transposed to the RTM of composites containing phenoxy nanocomposite films. The interlaminar energy release rate (GIc) of composite panels based on phenoxy with or without the nanofillers are measured and compared to the TP/NF-free reference.