Influence of functionalized exfoliated reduced graphene oxide nanoparticle localization on mechanical, thermal and electronic properties of nanobiocomposites

Abstract

This article reports unique microstructural development and enhanced mechanical and thermal properties of a biodegradable polylactide (PLA)/poly(ε-caprolactone) (PCL) blend through selective localization of functionalized thermally exfoliated reduced graphene oxide (f-TERGO) particles in the dispersed PCL phase. We used batch melt-blending to produce the PLA/PCL/f-TERGO composites with matrix of PLA and PCL. With the addition of 0.05 and 0.1 wt% f-TERGO to the polymers, there was no significant change in the blend morphology; however, at 0.25 wt% f-TERGO loading the size of the dispersed phase increased. The impact strength increased from 6 kJ/m2 for neat PLA to 10 kJ/m2 for the 0.1 wt% f-TERGO composite, whereas the elongation-at-break increased from 5% for neat PLA to 90% for the 0.05 wt% f-TERGO-filled composite. The thermal conductivity of the composites moderately increased with f-TERGO addition, which was associated with an increased number of nucleation sites in the f-TERGO-containing composites, homogenous spherulite growth, and increased crystallization temperature of the PCL phase. Unlike TERGO, f-TERGO addition did not increase electrical resistivity, clearly due to the surface functionalization. This study demonstrates the possibility of enhancing the toughness, melt-viscosity, and thermal conductivity of PLA by blending it with PCL and f-TERGO.