How nano-fillers affect thermal stability and flame retardancy of intumescent flame retarded polypropylene

Recent advances in flame retardant polymers have centered on the flame retardancy of nano‐fillers contained polymer nanocomposites. Among which, organo‐clay (OMMT), layered double hydroxides (LDHs), polyhedral oligomeric silsesquioxane (POSS), and carbon nanotubes (CNTs) have been reported and proved to be effective flame retardants for variable polymers. In this paper, a systematical study was executed on flame retarded polypropylene (PP) composites containing intumescent flame retardant (IFR) and the most popular nano‐fillers. Dispersion of the nano‐fillers was characterized by using transmission electron microscopy (TEM), the results revealed that all nano‐fillers dispersed homogeneously in PP matrix. The effects of nano‐fillers on thermal stability and flammable of PP were investigated by thermogravimetry (TG) and cone calorimetry tests, respectively. The results indicated that different nano‐fillers played different roles in thermal and flammability properties of composites. PP composites with OMMT gave the best reductions in heat release rate (PHRR) and endowed PP with relatively better flame retardancy. Copyright © 2011 John Wiley & Sons, Ltd.