Papers by Author: Jun Yang

Abstract: Polyamide 6-polyurethane (PA6-PU) block copolymers filled with graphite particles were prepared by anionic polymerization process. The friction and wear experiments were conducted using a UMT-3 machine with the chromium steel ball sliding on surface of the composites at high sliding speeds of 500rpm, 1000rpm and 1500rpm and loads of 78.5N and 157N. With adding of graphite, coefficient of friction and wear rate values of the composites decreased firstly, and then increased. And the influence of the applied load and sliding speed on tribological properties of the composites was explored in this study. The results showed coefficient of friction and wear rate values increased with the increasing of load. Coefficient of friction decreased and wear rate values increased with increasing of sliding speed. Microstructure of wear surface of the tested composites was inspected by scanning electronic microscope(SEM) and wear mechanism of the composites was studied.

Abstract: Polyamide 6/polyurethane/graphite composites have been prepared by anionic polymerization process. The effect of graphite concentration on mechanical properties of the composites was investigated. The test results show that with increment of graphite content, tensile strength of the composites increases firstly, and then decreases, while notch impact strength decreases. The change of mechanical properties of the composites is attributed to the dispersion of graphite, the interfacial properties between the matrix and graphite and the nucleation effect of graphite. In addition, the relationships between loss factor(Tan δ), storage module(E’) and temperature were investigated using Dynamic Mechanical Analysis(DMTA), and the morphological characteristic of the composites were studied using Scanning Electronic Microscope (SEM).