Flammability of carbon nanofiber–clay nanopaper based polymer composites

In this study, a hybrid nanopaper consisting of carbon nanofiber (CNF), and pristine montmorillonite clay (MMT, Cloisite Na⁺) was fabricated through a paper‐making process. The hybrid nanopaper was coated onto the surface of glass fiber (GF) reinforced polymer matrix composites through resin transfer molding process. The characterization results using scanning electron microscopy (SEM) and energy dispersion analysis of X‐ray (EDAX) show that the nanopaper had a porous structure and the polymer resin completely penetrated the hybrid nanopaper. The thermogravimetric analysis (TGA) test results revealed that the addition of MMT clay nanoparticles significantly enhanced the thermal stability of the nanopaper. The flammability of composite samples was evaluated by cone calorimeter test under a radiant heat flux of 50 kW/m². The peak heat release rate (PHRR) was dramatically reduced for the composites coated with the CNF–MMT nanopaper. For comparison, the composites coated with the CNF–organic MMT clay (OMT, Cloisite 20A) nanopaper were also evaluated with cone calorimeter test. The test results showed that the MMT clay was more effective than the OMT in the reduction of the PHRR. The combustion behavior of these samples was also examined by microscale combustion calorimetry (MCC) test. The PHRR obtained from the MCC test decreased with the MMT content in the nanopaper, which was in good agreement with cone calorimeter test results. Copyright © 2010 John Wiley & Sons, Ltd.