Study of thermal, flammability and mechanical properties of intumescent flame retardant PP/kenaf nanocomposites

Detrimental physical and mechanical properties are common pro-blems for composites when their flame retardancy is improved through filler additions.An increased interest of the synergistic nanoparticle addition to improve the flame retardancy of natural fiber composites is the aim of this work.The paper investigates the synergistic effect of two different nanoparticles(halloysite nano-tubes(HNTs)and montmorillonite(MMT)nanoclay)on the flame and mechanical properties in an intumescent ammonium poly-phosphate(APP)-based polypropylene(PP)/kenaf composite sys-tem.First,the nature of nanoparticle dispersion in PP through X-ray diffraction(XRD)and transmission electron microscopy(TEM)reveals that under twin screw compounding process,the partial exfoliation and intercalation have taken place within the nano-composites.An increase in the decomposition temperature was observed under thermogravimetric analysis(TGA),with the pre-sence of HNT.However,MMT tends to lower the maximum decomposition temperature under inert atmosphere.The flamm-ability analysis in an intumescent flame retardant(IFR)system shows that the suitable amount of high aspect ratio nanoparticles with their exfoliation characteristics effectively helps to reduce the sustained combustion.Even though,improved stiffness properties can be observed with the presence of increased filler content,particle agglomeration tends to reduce the mechanical strengths of these composites due to low compatibilization and crack propagation.