Study of Fire Retardant Performance of Composite Coated with Clay Containing Hybrid Carbon Nanofiber Paper

In this study, hybrid nanopapers consisting of carbon nanofiber and pristine montmorillonite clay (MMT, Cloisite Na⁺) were fabricated through the papermaking process. The as-prepared hybrid nanopapers were then coated onto the surface of glass fiber reinforced polymer matrix composites through resin transfer molding process. Characterization results using scanning electron microscopy and energy dispersion analysis of X-ray showed that the nanopapers had porous and highly entangled structures and the resin completely penetrated the nanopaper. The thermo-gravimetry analysis test results revealed that the addition of MMT clay nanoparticles significantly enhanced the thermal stability of the nanopaper. The fire retardant performance of composite samples was evaluated by cone calorimeter test under a radiating heat flux of 50 KW/m². The peak heat release rate was found to decrease dramatically for the CNF-MMT samples. For comparison with the CNF-MMT hybrid nanopaper, a sample coated with the CNF-organic MMT clay (OMT, Cloisite 20A) hybrid nanopaper was also evaluated with cone calorimeter test. The results showed that with the same weight ratio in the nanopaper, the MMT clay was more effective than the OMT in reducing the heat release rate. The combustion behaviors of these samples were examined by microscale combustion calorimetry test. The HRR obtained from the MCC test decreased with the increase of the MMT in the nanopaper, which was consistent with the cone calorimeter test results.