Exploring the influence of graphene incorporation on the characteristics of 3D-printed PLA

Additive manufacturing has revolutionized the production of intricate components, allowing for diverse material utilization, mainly polymers. However, polymer parts typically exhibit around 85% of the mechanical strength of injection-molded parts. Fillers have the potential to improve the mechanical properties of polymer-based additively manufactured components to meet specific design requirements. However, their incorporation requires careful assessment due to potential interactions with other material properties, necessitating a comprehensive evaluation. This study aimed to investigate the influence of graphene addition on the chemical, thermal, electrical, and mechanical characteristics of polylactic acid (PLA). Chemical characterization was performed using X-ray diffraction (XRD), Raman spectroscopy, and Fourier-transform infrared spectroscopy (FTIR). Thermal properties were analyzed via thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). Electrical properties were evaluated in terms of resistance, resistivity, and conductivity. Mechanical properties were assessed through tensile, flexural, notch sensitivity, and impact tests, as well as hardness measurements. Raman spectra of PLA graphene samples exhibited characteristic D, G, and 2D bands, while FTIR spectra showed no graphene-related peaks, indicating the lack of chemical interactions between graphene and the polymer matrix. XRD analysis indicated a low level of crystallinity, while DSC measurements unveiled alterations in the thermal characteristics. Graphene addition significantly influenced the fusion, crystallization, and crystallinity of PLA. Thermogravimetric analysis demonstrated the effect of graphene on the onset of thermal decomposition. Graphene imparted electrical conductivity to PLA making it conductive. Tensile and flexural tests demonstrated substantial improvements in strength, stiffness, and deformation. Single-edge notched bend and impact tests revealed changes in crack initiation, propagation, and fracture energy. Additionally, the incorporation of graphene increased PLA hardness.