The effects of crystallinity on the mechanical properties and the limiting PV (pressure×velocity) value of PTFE

In this work, the effects of crystallinity on the LPV (short for the limiting PV) value and tribological behaviors were investigated under different surface roughness and velocities. The experiment results revealed that the one which had a higher degree of crystallinity exhibited higher mechanical and thermal properties, lower friction coefficient and higher LPV value. The wear resistance was enhanced with the increase of crystallinity in rubbery state, since larger energy was needed to break the links between crystallites. In the present study, LPV value of PTFE reached to 2.5 Mpa m/s under 2 m/s. Surface roughness of 0.5 µm was the very profile in this work, which exhibited the best performance with the lowest friction coefficient and highest LPV value under 1 m/s.