Effect of graphene nanoplatelets (GNPs) incorporation on the mechanical and thermal properties of polyamide 6

The automotive industry increasingly demands lightweight, strong materials capable of large-scale production. Therefore, the objective of this work is to develop polyamide 6 (PA6) composites reinforced with graphene nanoplatelets (GNPs) that can be processed by injection molding. This study evaluates the effect of incorporation the GNPs reinforcement on the performance of PA6. The one-way ANOVA statistical analysis was used to evaluate the mechanical properties as a function of the composition of the composites obtained. A co-rotating twin-screw extruder was used to prepare the set of PA6/GNPs composites, followed by the injection molding process. Conventional characterization techniques were used to determine the properties of the composites, such as thermogravimetrical analysis (TGA), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), Field Emission Gun-Scanning Electron Microscopy (FEG-SEM), X-ray diffraction (XRD), tensile, flexural and impact strength tests. The GNPs were characterized using Raman spectroscopy, the Brunauer-Emmett-Teller (BET) method, field emission gun-scanning electron microscopy (FEG-SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and thermogravimetrical analysis (TGA). The results suggest that the graphene used has a sparse number of stacked layers and defects, classifying it as a better-quality material. The composites showed the best tensile and flexural properties. The addition of 5.25 wt% GNPs to PA6 resulted in a 22% improvement in Young´s modulus and a 10% improvement in tensile strength compared to neat PA6. Regarding flexural properties, the incorporation of 7 wt% GNPs into PA6 generated a 34% increase in flexural modulus of elasticity and a 17% increase in flexural strength. On the other hand, GNPs reinforced PA6 composites exhibited brittle material behavior, identified by low notch impact strength compared to neat PA6.