During the initial resin injection phase, the TP should remain insoluble. After complete mold filling and as a result of the temperature program applied to the system, the (amorphous) TP progressively dissolves into the epoxy resin precursor prior to substantial curing and gelling. Finally, the RIPS mechanism generates a morphology gradient that is a function of the local blend composition resulting from the interdiffusion between the TP and the resin precursors [36]. This approach can lead to a significant improvement of the composite performance in terms of mode I crack propagation resistance which is the dominant failure mode in compression after impact (CAI) [24], [27], [28], [34] and [37]. Among others, TP phenoxy has already demonstrated its remarkable ability to improve the fracture toughness of RIPS phase-separated systems without significant reduction of other properties of the epoxy network [24], [25] and [26]