1. Thermal aspects of polymer wear

Friction dissipates a mechanical power equal to : $\dot{W}=\mu P\mathrm{\Delta }u$

An increase in normal force P (or contact pressure p at a fixed contact area) and/or sliding speed Δu increases this power dissipation and the temperature of the parts, particularly in the contact zones. The mechanical properties of polymers are highly sensitive to temperature, and some, such as the elastic modulus and, even more so, the yield strength, drop sharply in the vicinity of certain temperatures, leading to structural transitions (melting of the crystalline phase, glass transition of the amorphous phase (table 1 to be consulted in the comparative report ); chemical...