Study of fire retardant behavior of carbon nanotube membranes and carbon nanofiber paper in carbon fiber reinforced epoxy composites

Single-walled carbon nanotube (SWCNT) and multi-walled carbon nanotube (MWCNT) membranes (buckypaper) and carbon nanofiber (CNF) paper were incorporated onto the surface of epoxy carbon fiber composites, as proposed fire shields. Their flammability behaviors were investigated by a cone calorimeter. SWCNT buckypaper and CNF paper did not show notable improvement on fire retardancy. However, MWCNT buckypaper acted as an effective flame-retardant shield, reducing the peak heat release rate by more than 60% and reducing smoke generation by 50% during combustion. The pore structures of buckypapers and CNF paper were characterized by scanning electron microscopy (SEM), mercury intrusion porosimetry, and N2 adsorption isotherms. Gas permeability of buckypaper and carbon nanofiber paper was measured. The correlation between buckypaper and CNF paper properties and their fire retardancy was discussed.