Comparison of mechanical properties and thermal stability of graphene-based materials and halloysite nanotubes reinforced maleated polymer compatibilized polypropylene nanocomposites

Abstract

This study compares the reinforcing effects of graphene nanoplatelets (GNP), graphene oxide (GO), and halloysite nanotubes (HNTs) in polypropylene (PP) based nanocomposites with PP-g-maleic anhydride (MAPP) as compatibilizer. PP/GNP/MAPP, PP/GO/MAPP, and PP/HNTs/MAPP nanocomposites were fabricated at nanofillers contents 1, 2, 3, 4 parts per hundred (phr) and MAPP at 4 phr, to PP matrix, using melt extrusion and injection molding techniques. Results show that at nanofillers optimum content, PP/GNP3/MAPP nanocomposite increased in tensile strength and modulus by 8% and 96%, respectively, compared to pure PP (p ˂ 0.05). PP/GNP3/MAPP nanocomposite also increased in tensile strength and modulus by 2% and 4% respectively, compared to PP/GO2/MAPP (p ˂ 0.05) and 2% and 15% compared to PP/HNTs2/MAPP (p ˂ 0.05) nanocomposites. For impact strength performance, PP/GNP2/MAPP nanocomposite increased in impact strength (notched) by 104% compared to pure PP (p ˂ 0.05). Also, PP/GNP2/MAPP nanocomposite increased in impact strength by 23% compared to PP/GO1/MAPP (p ˂ 0.05) and 13% compared to PP/HNTs1/MAPP (p ˂ 0.05), nanocomposites. In flexural properties, PP/GO4/MAPP nanocomposite increased in flexural strength and modulus by 24% and 28%, respectively, compared to pure PP (p ˂ 0.05). Also, PP/GO4/MAPP nanocomposite increased in flexural strength and modulus by 4% and 9%, respectively, compared to PP/GNP2/MAPP nanocomposite, and 9% and 21% respectively compared to PP/HNTs2/MAPP nanocomposite. PP/GNP2/MAPP nanocomposite increased in thermal stability by 12°C compared to pure PP; 29°C compared to PP/GO2/MAPP; and 15°C compared to PP/HNTs2/MAPP nanocomposites. Overall, PP/GNP/MAPP nanocomposite exhibited superior mechanical properties and thermal stability compared to PP/GO/MAPP and PP/HNTs/MAPP nanocomposites. PP/GO/MAPP was superior for bending properties while PP/HNTs/MAPP was best for ductility.