Improved flame retardancy and thermal stability of polymer/clay nanocomposites, with the incorporation of multiwalled carbon nanotube as secondary filler

Abstract

In the present study, the combined effect of multiwalled carbon nanotube (MWNT) and organoclay in improving the flame retardancy and thermal stability was evaluated. A novel ternary nanocomposite (polymer/organoclay/MWNT) material based on polypropylene, organoclay and MWNTs has been developed. Higher degree of delamination of clay layers in ternary nanocomposites as compared to polymer/clay nanocomposites via x-ray diffraction and transmission electron microscopy analyses was evident, and also the network structure of MWNT and clay was evident. In ternary nanocomposites, the more intact network structure was also evident from the rheological assessment. Improved thermal stability and flame-retardancy characteristics were evident from thermogravimetric and cone calorimeter analyses. Also the scanning electron microscopic micrographs of char residue revealed a correlation with the cone calorimeter. The role of degree of graphitization of MWNTs on the flammability of nanocomposites was also confirmed from the analysis.