Improving Physical Properties of Polypropylene Nanocomposites by a Natural Resource-Based Bottom-up Graphene Oxide Filler

Polypropylene (PP) nanocomposites were prepared using bottom-up graphene oxide (BGO) functionalized with cardanol having a long alkyl group as a filler. BGO was prepared from citric acid and tannic acid, and then further functionalized with cardanol glycidyl ether (CGE), where CGE was synthesized by reacting cardanol with epichlorohydrin to produce cardanol functionalized BGO (CBGO). PP nanocomposites were fabricated by mixing PP and CBGO using twin-screw extruder, where the content of CBGO ranged from 0.5 to 5.0 wt%. PP nanocomposite containing 2.0 wt% of CBGO (PP/CBGO-2.0) showed the maximum mechanical properties. The effect of the alkyl group in CBGO on the mechanical properties was investigated by comparing the mechanical properties of PP/CBGO-2.0 with those of PP nanocomposite with 2.0 wt% BGO (PP/BGO-2.0). For example, the tensile strength and Young’s modulus of PP/CBGO-2.0 increased by 20.1% and 30.6%, respectively, compared to neat PP, while those of PP/BGO-2.0 increased by 14.7% and 25.0%, respectively.