The synergistic effects of micro-and nano-fillers on the properties of polyamide 11/poly (lactic acid) blend

Abstract

This study focused on investigating the effects of micro-scale carbon fibers (CF) and nano-scale graphene nanoplatelets (GNP) on the morphological, rheological, mechanical, thermo-mechanical and thermal properties of polyamide 11/poly (lactic acid) (PA11/PLA) blend. A twin-screw extruder and an injection molding machine were utilized to produce the samples. The amount of GNPs was varied up to 5 wt% for a fixed CF fraction of 20 wt%, and the composites were characterized. SEM micrographs of hybrid composites revealed stronger interfacial interactions between the matrix and CF and improved dispersion of GNPs. The pseudo solid-like behavior transition and high modulus detected in the rheological study with the addition of GNP confirmed the strong matrix-filler interactions in hybrid composites. The synergistic effects of multi-scale fillers have been observed in mechanical and thermo-mechanical properties. In comparison to 20CF, hybrid composites’ tensile strength and modulus increased by 8%–4.8% and 4.5%–17%, respectively, by adding 0.5–5 wt% GNP. Dynamic mechanical analysis revealed that the tan δ peak shifted to higher temperatures in low GNP containing hybrid composites, indicating an increase in Tg. Also, differential scanning calorimetry confirmed the Tg increment and synergistic effect of fillers on crystallization. The thermogravimetric analysis demonstrated that hybrid composites exhibited enhanced thermal stability. As a consequence, these hybrid composites offer an inventive viewpoint for environmentally friendly composites in the automobile industry thanks to their enhanced mechanical and thermal characteristics.