Optimisation of carbon fibre reinforced polymer composites with a thin embedded polyurethane film: Twenty-second International Conference on Composite Materials (ICCM22)

The aim of this work is a preliminary study of interleaved hybrid polymer composites used for impact energy absorption. The interlaminar properties of optimised pre-impregnated carbon fibre reinforced polymer (CFRP) hybrid laminated composites, containing thermoplastic polyurethane (PU) interleaves, have been measured. Two common manufacturing methods have been used to manufacture the laminates; vacuum bag consolidation (VB) and hot press consolidation (HP). The interlaminar fracture toughness (Mode I) of the optimised laminates was twice that of the reference laminate for both VB and HP, and almost 10% higher when changing the manufacturing process from VB to HP. The results indicated good bonding between the thermoplastic interleave and the epoxy. The adhesion between the CFRP epoxy and the PU film has a significant effect on the crack propagation behaviour of the structure, e.g., fibre bridging is reduced, and there is good adhesion. To study this adhesion, scanning electron microscopy (SEM) was used to observe the interface between the two phases. The preliminary quasi-static tests show that there is no significant reduction of the mechanical properties of the optimised PU laminates. For this reason, thermoplastic materials are frequently used for absorption of impact energy to improve laminate damage tolerance.