Influences of organic montmorillonite on the combustion behaviors and thermal stability of polyamide 6/polystyrene blends

Abstract

The nanocomposites of polyamide 6/polystyrene (PA6/PS) with different contents of organic montmorillonite (OMMT) have been obtained by melt blending. The combustion behaviors, morphology of char residues, and thermal stability of nanocomposites have been characterized by cone calorimeter tests (CCT), electron probe microanalysis, scanning electron microscopy (SEM), and thermogravimetric analysis (TGA). The CCT results indicated that the OMMT was an efficient flame retardant (FR) in the FR-PA6/PS blends. The heat release rates, the total heat release, and carbon monoxide and carbon dioxide production of the FR nanocomposites decreased in comparison with PA6/PS blends. The SEM photographs showed that the “spongy” structure on the surface of char residues increased. In addition, the thickness and strength of char residues enhanced with the increase of OMMT content. The tight multilayer carbon silicate layer structure was formed which was conducive to FR. The TGA data indicated that OMMT greatly enhanced the thermal stability, and char residues of PA6/PS/OMMT nanocomposites gradually increased with increasing the OMMT content.