Synergistic effect of decabromodiphenyl ethane and montmorillonite on flame retardancy of polypropylene

Polypropylene (PP) is melt-compounded in a twin-screw extruder with surface-modified decabromodiphenyl ethane/antimony trioxide (DBDPE/Sb2O3) and organically modified montmorillonite (OMMT). The intercalation and dispersion microstructure of OMMT in the nanocomposites are investigated by X-ray diffraction, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Thermal stability and char residue are characterized by thermogravimetric and differential thermal analysis (TGA-DTA). Flame retardant properties are evaluated by limited oxygen index (LOI) and UL-94 vertical burning test.The results indicate that better flame retardancy can be achieved for the composite containing a modified mixture DBDPE/Sb2O3. The presence of DBDPE/Sb2O3 could improve the dispersion of OMMT in polypropylene, leading to higher thermal stability and more char residue. A synergistic effect between OMMT and DBDPE/Sb2O3 has been observed and discussed.