Effect of functionalized graphene on mechanical and rheological properties of melt processed polyamide 6 nanocomposites

Abstract Nanocomposites of functionalized graphene (FG) and polyamide 6 (PA6) were prepared through the twin‐screw extrusion method by the routes of solution‐assisted masterbatch technique and dry mixing of nanomaterials with the virgin polymer. Scanning electron microscopy (SEM), X‐ray diffractometry (XRD), Raman spectroscopy, Rheological analysis, and tensile tests were performed to determine the best nanocomposite manufacturing route. The dispersion state proved to be the best for the 1 wt% FG/PA6 nanocomposite (1‐FG) prepared by the dry mixing method based on the characterization and analysis methods performed. Tensile properties were noticeably improved for the 1‐FG nanocomposite by 32.7% and 8.7% for Young's modulus and tensile strength, respectively. The presence of a network of nanomaterials was also spotted in SEM and rheological analysis. It was also found that the presence of trapped solvent molecules for the masterbatch solution method resulted in altered tensile properties and lowered rheological enhancements compared with its dry‐mixed counterparts. Raman spectroscopy was also proven capable of analyzing the degree of dispersion analogous to XRD or rheological analysis for the first time. Furthermore, the presence of vacuum degassing during the melt processing of nanocomposites was experimentally proven to be a must since FG particles get in‐situ reduced by the high temperature of the melt processing, resulting in the generation of gaseous species that critically sabotage melt processing in the absence of vacuum. Highlights Reduction of graphene in the melt processing sabotages the process. Vacuum degassing controls gaseous species generated due to graphene reduction. Dry mixing of materials proved to be better than the solution masterbatch method. Raman is capable of analyzing dispersion quality analogous to rheometric mechanical spectrometer (RMS) and XRD. In the solution masterbatch path, graphene retards solvent removal in degassing.