Effect of tensile and compressive properties on the scratch behavior of injection-molded polycarbonate model systems

The scratch behavior of injection-molded model polycarbonate (PC) systems was investigated according to the ASTM scratch test methodology. Four model PC systems with different tensile and compressive yield stresses were investigated to determine what are the governing parameters determining the scratch visibility and scratch cracking resistance. Coefficient of friction (COF) measurements, uniaxial tensile and compressive true stress- strain curves, and dynamic mechanical analyses were conducted to correlate the intrinsic material properties to the observed scratch-induced deformation of the model PC systems. Special attention is given to how the geometric scratch parameters, such as scratch depth and shoulder height, correlate with the mechanical properties and the scratch visibility of the model PC systems. It is found that the tensile yield and compressive yield stresses and surface characteristics and the COF dominate the scratch deformation process, thus the scratch performance of PC.