Polypropylene-graft-maleic anhydride-nanocomposites: II - fire behaviour of nanocomposites produced under nitrogen and in air

The characterization and thermal stability of polypropylene-graft-maleic anhydride-clay blends were described in the first paper of this series. In the present article, fire performance studies, supplemented by thermogravimetric/Fourier transform infrared (TGA/FTIR) analysis and permeability to gases of the blends were performed. There was a dramatic reduction in peak heat release rate for the nanocomposites compared to pure polypropylene-graft-maleic anhydride and its hybrid. It was shown that the improved flammability happened in the condensed phase and is not likely to be due to a higher thermal stability of the nanocomposite. The impermeability of the silicate layers in the polymer, which reduced the diffusion of gases in the nanocomposites may participate in the reduction of the flammability. TGA/FTIR analysis in the presence or absence of air gave some clues to the chemistry of reactions during the combustion.