Effect of processing sequence on the mechanical and tribological properties of ternary nanocomposites (VGCF-X/PA6/HDPE)

Abstract

The aim of this study is to develop the new tribomaterials for mechanical sliding parts with sufficient balance of mechanical and tribological properties. The effect of processing sequence on the mechanical and tribological properties of ternary nanocomposites (VGCF-X/PA6/HDPE) was investigated: the polymer blends of polyamide 6 (PA6) and high density polyethylene (HDPE) filled with vapor grown carbon fiber (VGCF-X) which is one of the carbon nanofiber and has 15nm diameter and 3μm length. Five different processing sequences, (1) VGCF-X, PA6 and HDPE were mixed simultaneously (Process A), (2) Re-mixing (Second compounding) of the materials prepared by Process A (Process AR), (3) VGCF-X was mixed with PA6 (VGCF-X/PA6 composites) and then these composites were blended with HDPE (Process B), (4) HDPE was blended with PA6 (PA6/HDPE blends) and then these blends were mixed with VGCF-X (Process C), (5) VGCF-X were mixed with HDPE (VGCF-X/HDPE composites) and then these composites were blended with PA6 (Process D) were attempted for preparing of the ternaery nanocomposites (VGCF-X/PA6/HDPE). These ternary polymer nanocomposites were melt mixed by a twin screw extruder and injection-molded. Their mechanical properties such as tensile, Izod impact and Durometer hardness, and tribological properties were evaluated. Tribological properties were measured by a ring on plate type sliding wear tester under dry condition. The mechanical and tribological properties changed in according with the processing sequence of ternary nanocomposites (VGCF-X/PA6/HDPE). These may be attributed to the change of the internal structure formation of these ternary nanocomposites, which is dispersibility and localization of VGCF-X in these ternary nanocomposites by different processing sequences.