Graphene oxide/ polylactic acid composites with enhanced electrical and mechanical properties for 3D-printing materials

Abstract

Polymeric materials have gained significant attention as a captivating class of materials in the realm of additive manufacturing. Nevertheless, their extensive use remains constrained due to inherent limitations of low mechanical strength, thermal and electrical properties. Consequently, polymer composites are attaining consideration of the researchers for the development of customized materials with specific applications. In the present work, graphene oxide (GO) was synthesized using pencil lead as a precursor via modified Hummer's method and used for the fabrication of GO-based polylactic acid (PLA) composites with GO concentration variation from 0.25 wt% to 1.25 wt% with a step size of 0.25. The molecular conformation and characteristics of synthesized GO were analysed by X-ray diffraction (XRD), Energy dispersive X-ray spectroscopy (EDX), Raman spectroscopy, and Fourier transform infrared spectroscopy (FTIR). For mechanical and electrical properties evaluations, the required specimens were fabricated by direct ink writing through syringe extrusion method. It was observed that the 0.5 wt% loading graphene oxide showed the maximum value of tensile strength; however, 1.25 wt% GO content resulted in highest young's modulus. In contrast, at 1.25 wt% GO loading, compressive strength and microhardness exhibited the highest value among all the composites. The highest value of electrical conductivity of 58.91 µS/m was observed at 1.25 wt% GO content. However, maximum dielectric constant value of 307.69 was obtained at 1 wt% GO loading at100 Hz frequency. Thus, in our findings, the inclusion of a small amount of GO in PLA matrix enhanced the mechanical as well as electrical properties. © 2025 Elsevier B.V.