Modeling, processing, and characterization of exfoliated graphite nanoplatelet-nylon 6 composite fibers

We present theoretical and experimental studies on the effects of platelet-like filler orientation on the mechanical properties of melt-spun exfoliated graphite nanoplatelet(xGnP)-nylon 6(PA6) composite fibers. In numerical studies, the Mori-Tanaka micromechanics model was employed to formulate analytical models to predict the mechanical properties of xGnP-PA6 composite fibers with varying xGnP orientations in a three-dimensional spatial domain. Simulation results showed that the predicted properties of xGnP-PA6 composite fibers were highly affected by xGnP orientation and were correlated with the measured properties of composite fibers treated with varying draw ratios. The tensile moduli of composite fibers at varying xGnP contents showed significant improvements, which is attributed to the drawing-induced alignment of PA6 molecular chains as well as the alignment of xGnPs. Both as-received and acid-treated xGnPs were incorporated in PA6, and mechanical test results suggested that acid-treated xGnPs provide stronger interfacial bonding with PA6.