Fire performance of composite laminates embedded with multi-ply carbon nanofiber sheets

In this study, free-standing carbon nanofiber sheets (CNS) were incorporated into glass fiber reinforced polyester composites through resin transfer molding (RTM) process. These sheets were made of vapor grown carbon nanofibers. The composite laminates consisted of eight plies of CNS and eight plies of glass fiber mats. The fire retarding performance of the laminates was evaluated with cone calorimeter tests with an external radiated heat flux of 50kW/m2. The test results indicated that there was significant improvement in the fire retardancy of composite laminates due to the incorporation of CNS. It was found that the CNS plies survived the test except the one on the top surface of the laminates. The formation of compact char materials was observed on the surface of the CNS residues. The improvement in fire retarding performance was achieved through the barrier and insulator effects of the CNS and charred materials by restricting the migration of flammable products to the top surface of the laminates and preventing the transmission of external heat to the underlying polyester resin.