Effects of ammonium polyphosphate content on mechanical, thermal and flammability properties of kenaf/polypropylene and rice husk/polypropylene composites

This study investigated the effects of ammonium polyphosphate (APP) content on the mechanical, thermal and flammability properties of kenaf/polypropylene (KF/PP) and rice husk/polypropylene (RH/PP) composites prepared by melt mixing technique. Polyethyleneoctene grafted maleic anhydride (POE-g-MAH) has been used as compatibilizer. The PP/KF/APP and PP/RH/APP composites were investigated using flexural and impact tests, scanning electron microscope, thermogravimetric analysis (TGA), differential scanning calorimeter and limiting oxygen index (LOI) test. Flexural modulus of PP/KF/APP and PP/RH/APP composites significantly improved from approximately 1.1-2.5 and 0.9-2.1 GPa, respectively, by the addition of 10 phr APP. The flexural strength of the composites also increased by the incorporation of 10 phr APP. In addition, the impact strength of the PP/RH/APP composites increased above 10 phr APP content. From the TGA results, incorporation of APP into PP/RH and PP/KF composites increased the char residue and thermal stability of the composites. Furthermore, the addition of APP increased the flame retardancy of the PP/ICF/APP and PP/RH/APP composites with a significant increase of LOI at 10 phr. (C) 2017 Elsevier Ltd. All rights reserved.